Method and apparatus for filtration with plural ultraviolet treatment stages

An improved filtration system involving the use of ultraviolet irradiation, ozonation, chlorination, reactive filtration media, chemical treatment, compressed air aeration, air emission control, and central flow control is described. The process system and apparatus of the present invention mainly include a liquid pump, an ultraviolet pretreatment means, a central flow control, an air emission control means, a reactive pressure filter, a process tank, at least one chemical feeder means, an ultraviolet post-treatment means, and an aeration means. The filter media are of reactive type, including diatomaceous earth, granular activated carbon, fibrous activated carbon, granular metal medium, greensand, neutralizing sand, silica sand, activated alumina, ion exchange resins, polymeric adsorbents, chemical treated adsorbents, manganese oxide, coal, porous plastic medium, porous stainless steel medium, porous ceramic medium, bacteriostatic filter medium, porous paper filter medium, porous carbon filter medium, coalescing filter medium, fiberglass filter medium, or combinations thereof. The process tank contains and handles regenerating chemicals, flocculating chemicals, filter aids, or recirculating water. The reactive filter media of this invention are regenerated by either chemical reactions or aeration for reuse to prolong the filter media's service life and to reduce the operation and maintenance costs. Said air emission control means is provided when compressed air aeration is applied to said pressure filter for regeneration of said reactive filter media. The apparatus of this invention is compact and simple, and can cost-effectively remove suspended, dissolved, volatile, radioactive and living contaminants from a contaminated liquid.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a reactive filtration apparatus and 
process for removal of living, suspended, soluble, volatile and 
radioactive contaminants from a contaminated liquid. Specifically, the 
filtration apparatus and process of this invention involves mainly the use 
of reactive filtration media, an ultraviolet irradiation means, chemical 
treatment means, pump means, an aeration means, an air emission control 
means, a central flow control, a pressure filter and a process tank. 
2. Description of the Prior Art 
There are two types of conventional granular media filters: slow sand 
filters and rapid sand filters. Neither conventional filter can remove any 
radioactive radon, volatile trihalomethane, living pathogenic bacteria, or 
soluble hardness and metals. A typical conventional slow sand filter is 
commonly operated at below 0.16 gpm per square foot, using unstratified 
non-reactive sands with an effective size of 0.3 mm to 0.35 mm and a 
uniformity coefficient of 2 to 3. Aside from the low hydraulic load, 
conventional slow sand filters appear to lack the technological 
sophistication of their successors, conventional rapid sand filters which 
are operated at 2 gpm per square foot or higher, using stratified 
non-reactive sands with an effective size of 0.45 mm and higher and an 
uniformity coefficient of 1.5 or lower. Both types of conventional filters 
have operation and maintenance problems. Ordinarily the surface of a 
partially dewatered slow sand filter bed is raked after about 2 weeks of 
filter run, and again a week or so later to break through the surface 
accumulations. At the end of a month, the top portion up to 2 inches of 
the slow sand bed and the surface accumulations must be scraped off for 
disposal. Conventional rapid sand filters are superior to conventional 
slow sand filters for water filtration, but are comparatively more 
complicate, and can only be operated by experienced operators. 
Furthermore, both conventional slow sand filters and conventional rapid 
sand filters remove only suspended particulates from water. Radioactive 
contaminants, such as radon gas, and soluble contaminants, such as iron, 
manganese heavy metals, volatile organic compounds, and hardness can not 
be removed by any conventional sand filters. 
Recently, the design of granular media filters has been advanced to include 
granular activated carbons, activated alumina, anion exchange resins and 
cation ion exchange resins for removal of soluble contaminants. Other 
state-of-the-art processes for water purification include reverse osmosis, 
electrodialysis, packed column, ultrafiltration, microfiltration, 
diatomaceous earth filtration, flotation-filtration, etc. The common 
problems for the state-of-the-art as well as conventional filters are 
their high cost and time-consuming procedures for operation and 
regeneration. 
There has been no ideal process or apparatus developed for removal of 
radioactive radon gas from a contaminated liquid. 
The present invention adopts both reactive filter media and non-reactive 
filter media for specific chemical reaction and liquid-solid separation, 
and adopts at least one central flow control means for the ease of routine 
water treatment. The present invention's apparatus is compact, and its 
process is simple and cost-effective, and removes suspended, dissolved, 
volatile, radioactive, and living contaminants from a contaminated liquid, 
such as surface water or groundwater. The reactive filter media of this 
invention are regenerated by liquid chemical solutions or compressed air 
aeration depending upon the liquid purification applications. 
None of the prior arts including Barrows (U.S. Pat. No. 103,280; 5/1870), 
Potter (U.S. Pat. No. 619,838, 2/1899), Moon et al (U.S. Pat. No. 
2,993,599, 7/1961), Griswold (U.S. Pat. No. 3,064,816, 11/1962), Lindstol 
(U.S. Pat. No. 4,082,664, 4/1978), Litzenburger (U.S. Pat. No. 4,430,220, 
2/1984), Hall et al (U.S. Pat. No. 4,626,346, 12/1986), Heskett (U.S. Pat. 
No. 4,642,192, 2/1987), Swinney et al (U.S. Pat. No. 4,673,498, 6/1987), 
Krofta (U.S. Pat. No. 4,377,485, 3/1983; No. 4,626,345, 12/1986; 
4,673,494, 6/1987), Weber et al (U.S. Pat. No. 4,973,404, 11/1990), and 
Wand et al (U.S. Pat. No. 5,064,531, 11/91; No. 5,069,783, 12/91) relate 
to the use of ultraviolet light, reactive granular filter media, chemical 
regeneration, aeration regeneration, central flow control, and special 
hydraulic flow pattern in combination for water purification and air 
emission control as in the case of this present invention. 
None of the aforementioned prior arts can remove radon form a contaminated 
liquid. Conventional crossflow separation processes include reverse 
osmosis, ultrafiltration, microfiltration and gas permeation which are all 
membrane processes, and cannot remove radioactive contaminants. The 
present invention relates to a central controlled crossflow reactive water 
filtration process in which the filter media are regenerative with 
ultraviolet, ozone, hydrogen peroxide, hypochlorite, permanganate, and by 
which radioactive, living and non-living contaminants are efficiently 
removed under a pressurized hydraulic condition for a prolonged filter 
run. 
All conventional granular media filtration processes adapt either an upflow 
or a down-flow hydraulic operation during which the direction of influent 
flow is parallel with the flow path of granular media filtration. In the 
case of the present invention's crossflow reactive filtration process, the 
direction of influent flow is perpendicular to the flow path of granular 
media filtration. 
Non-reactive filtration processes remove mainly suspended particulates from 
water. A reactive filtration process, as in the case of the present 
invention removes dissolved, volatile, radioactive and living contaminants 
in addition to its capability for suspended particulates removal. 
The major advantages of the present invention over conventional filtration 
processes include: (a) pretreatment and/or post-treatment of reactive 
filtration with ultraviolet, ozonation, hydrogen peroxide, permanganate, 
and dry hypochlorite for total destruction of living contaminants; (b) 
adoption of a central flow control for the ease of nine water filtration 
operations: normal filtration, backwash, bypass, flushing, chemical 
preparation, recirculation, rinse, precoat, and desorption; (c) adoption 
of both reactive and non-reactive filter media for removal of suspended, 
dissolved, volatile, radioactive and/or living contaminants; and (d) 
adoption of an aeration means for the in-apparatus regeneration of 
reactive filter media. Both total removal of volatile, radioactive and 
living contaminants and simple central control operation make the present 
invention extremely attractive to the single families and small 
institutions for their point-of-entry (POE) in-house operations. 
The similarities and dissimilarities between the present invention and the 
selected important prior arts are further described below. 
British Patent No. 842, issued to Chemesha et al in March, 1870 is of 
interest in citing "safety valves", which are now required for any 
pressure systems including the present invention. While the safety valves 
and pipes are the required parts of the present invention, they are not 
considered to be major components of the present invention which places 
emphasis on a central controlled reactive and regenerative filtration 
process. 
All Krofta processes (U.S. Pat. Nos. 4,377,485, 4,626,345 and 4,673,494) 
are similar to a flotation-filtration system described by Wang (U.S. Dept. 
of Commerce, NTIS Report PB89-158398/AS, October, 1988; Water Treatment, 
p. 127-146, 1991; Water Treatment, p. 1-16, 1992). While the 
flotation-filtration process is feasible for removal of color, 
trihalomethane precursors and Giardia Cysts, the flotation-filtration 
process system involves the use of too many valves and treatment steps, 
and thus can only be adopted by municipalities which have skilled 
operators. The treatment steps of a flotation-filtration system include: 
chemical mixing, chemical flocculation, dissolved air flotation, 
non-reactive sand filtration, and chlorination, which are different from 
the present invention. 
Advanced Wang process (U.S. Pat. Nos. 5,064,531 and 5,069,783, issued to 
Lawrence K. Wang et al in 1991) which are specifically developed for large 
municipalities, do not relate to air emission control and radon removal. 
Filtration apparatus which adopt multi-port control values for feeding 
filter aids are shown in U.S. Pat. No. 3,064,816 issued Nov. 20, 1962 to 
David E. Griswold and in U.S. Pat. No. 4,973,404 issued Nov. 27, 1990 to 
Roland E. Weber, John J. Pavlovich and Lawrence K. Wang. Both filtration 
apparatus (U.S. Pat. Nos. 3,064,816 and 4,973,404) involve the use of too 
many valves and non-reactive and non-regenerative granular filter media, 
for removal of suspended contaminants. The present invention involves the 
use of only one or two central flow controls (depending upon the hydraulic 
capacities) and reactive/regenerative filter media in conjunction with 
ultraviolet irradiation and air emission control means for removing 
suspended, dissolved, volatile, radioactive and living contaminants. 
A prior filtration apparatus using multiport valves for cleaning of filters 
and delivering adequate pressure is described in U.S. Pat. No. 103,280, 
issued May 24, 1870 to Thomas Barrows. Barrows' patent is particularly 
directed to a non-reactive, non-regenerative pressure filter using several 
three-way valves. Although Barrows' apparatus can be operated horizontally 
or vertically, it is not a crossflow separation process in accordance with 
the state-of-the-art engineering definition. Currently only the membrane 
processes (reverse osmosis, microfiltration, ultrafiltration, and gas 
permeation) are designed and classified as crossflow separation processes 
in which the influent water (Qi) is fed to an inlet of said apparatus at 
one end traveling in parallel with the membrane filtration medium; its 
concentrate (Qc) is discharged in small volume at the opposite end; and 
the filter effluent (Qe=Qi-Qc) passing through the membrane filter medium 
is discharged from the second outlet also at the opposite end of said 
apparatus. The present invention partially relates to a crossflow granular 
filtration process and apparatus in which the filter media (instead of 
membrane filter medium) is reactive/regenerative (instead of 
non-reactive/non-regenerative), and one central flow control means has 
nine operational modes (instead of several three-way valves). 
Still another apparatus for filtering water through porous media is shown 
in U.S. Pat. No. 619,838, issued Feb. 21, 1899, to Zoroaster F. Potter. 
Specifically, Potter's patent relates to a filtration apparatus comprising 
a chemical process tank coupled to a chemical feed system, an old central 
flow control valve with a handle for dialing and handling limited water 
flows only, a pressure filter containing non-reactive/non-regenerative 
granular filter media, an influent inlet, product liquid discharge pipe, 
waste drain, many multiple on-off ports, all connected with a piping 
system which contains a plurality of safety valves. The process of the 
present invention relates to a pressurized crossflow filtration using 
reactive/regenerative filter media, and using ultraviolet, ozone, hydrogen 
peroxide, permanganate, flocculants and hypochlorite as pretreatment 
chemical and/or post-treatment chemical. The apparatus of the present 
invention comprises a process tank coupled to a chemical feed system for 
liquid pretreatment and filter media regeneration (instead of feeding 
chemical only as in the case of Potter's patent), a modern central flow 
control means with nine process operational modes to handle water flows, 
desorption gas, and filter media slurry (instead of limited operational 
modes and handling only water flows), a pressure filter containing 
reactive/regenerative filter media (instead of 
non-reactive/non-regenerative granular filter media), an air emission 
control means (instead of no air emission control), an influent liquid 
pipe, effluent discharge pipes and a waste drain, all connected to the 
modern central flow control means (instead of all connected with a piping 
system). Besides, simplicity in operation is the major improvement of the 
present invention, because multiple on-off valves are grouped together and 
there is an aeration means for in-apparatus regeneration of reactive 
filter media for reuse. 
Still another prior filtration apparatus for automatic flow control is 
shown in U.S. Pat. No. 2,993,599 issued Jul. 25, 1961 to John J. Moon and 
Harold M. Hawkins. Their patent discloses a new control technology for 
automation of a precoat filtration process involving the use of a cycle 
timer, air inlets, air vents, wash solvent lines, sluice solvent lines, a 
precoat mix tank, a pressure filter, a filter feed line, an effluent line, 
a wash recycle line, a wash vapor receiver, drains, a filter cake 
discharge line, a pressure pump, safety valves, pressure gauges, flow 
meters, over 20 flow control valves, and a turbidity monitor. The 
apparatus of the present invention also comprises a pressure filter, a 
filter feed line, an effluent line, a recycle line, drains, a pressure 
pump, pressure gauges, a flow meter, a safety valve, and a tank. However, 
in the case of the present invention, the major improvements are: one 
central flow control means (instead of over 20 valves), one multi-purpose 
process tank (instead of one single-purpose tank just for precoating), one 
pressure filter containing reactive/regenerative filter media (instead of 
non-reactive/non-regenerative granular filter media), being operated as 
rotating crossflow hydraulic pattern horizontally or vertically (instead 
of non-crossflow hydraulic pattern), and having adequate pretreatment and 
post-treatment for removal of living, non-living, radioactive, suspended 
and dissolved contaminants (instead of having no pretreatment and no 
post-treatment for removal of mainly non-living suspended contaminants), 
all aiming at simplicity in operation and high efficiency in water 
purification. In addition, the present invention's apparatus does not 
require complicated automation when applied to single families and small 
institutions because of its one central flow control operation. For 
municipal applications, the present invention is automated mechanically 
and electrically (instead of electronically as in the case of Moon et al) 
again because of its simple central flow control operation. 
A method for treating fluid to remove undesirable constituents contained 
therein such as chlorine and nitrate constituents is disclosed in the U.S. 
Pat. No. 4,642,192, issued Feb. 10, 1987 to Don E. Heskett. Heskett's 
method includes passing fluid containing chlorine and nitrate through a 
bed of granular metal particulate matter, having favorable redox 
potentials relative to the redox potentials of the undesirable 
constituents so as to establish conditions for spontaneous oxidation and 
reduction reactions between the undesirable constituents and the metal 
particles. Heskett's method relates to water treatment using only the 
metal particles. The present invention relates to a central controlled 
filtration system with pretreatment and post-treatment, and the metal 
septum (instead of metal particles) is one of eleven filter media adapted 
by the newly improved pressure filter. The Heskett's method cannot remove 
volatile, radioactive and living contaminants, but the present invention's 
method can. 
Prior art concerning treatment of gas effluent from multistep liquid 
treatment systems has also been reviewed. Carnahan et al merely treat a 
gas effluent in a reactor tank with chlorine, in accordance with their 
U.S. Pat. No. 4,919,814. Irvine et al suggests such gas effluent being 
treated by carbon adsorption followed by membrane separation in accordance 
with their U.S. Pat. No. 5,126,050. (Col. 11, lines 36-41.) U.S. Pat. No. 
4,894,162, awarded to Cournoyer et al in January 1990, suggests such gas 
effluent being treated by venturi dilution and collection in a tank where 
microorganism action purifies the gas. Anderson's U.S. Pat. No. 4,391,704 
suggests venturi dilution, treatment with chlorine or ozone and 
adsorption. Meidl's U.S. Pat. No. 4,857,198 suggests initial adsorption 
followed by recycling of such gas effluent back to the treatment system. A 
publication by Waltrip et al (Journal WPCF, Vol. 57, No. 10, 1985) 
suggests primarily treatment of such gas effluent in a scrubber. The 
method and apparatus of this invention, however, relates to an air 
emission control means comprising a tank, at least one prescreen, a gas 
mover, a venturi dilution means, a demister, an adsorber, valves, and 
pipes. Said prescreen of this invention further comprises a coalescing 
filter screen, a fiberglass filter screen, a fibrous activated carbon 
filter screen, or combinations thereof. Said adsorber of this invention is 
packed with virgin granular activated carbon, virgin fibrous activated 
carbon, ion exchange resins, polymeric adsorbent, base treated activated 
carbon, aluminate treated activated carbon, base treated polymeric 
adsorbent, aluminate treated polymeric adsorbent, reticulated foam, 
fiberglass screen, fibrous activated carbon screen, coalescing filter 
screen, or combinations thereof for removal of radioactive and volatile 
contaminants from a gas effluent which will not be recycled. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, an improved method and apparatus 
for removing suspended particulates, volatile organic compounds, heavy 
metals, iron, manganese, hardness, oil and grease, bacteria, radioactive 
gas, and odor from a contaminated liquid comprises the following steps, 
facilities and alterations: 
(a) packing a pressure filter of said apparatus with a septum (i.e. filter 
element) and filter media which are selected from a group including 
diatomaceous earth, granular activated carbon, granular metal medium, 
chemical treated adsorbents, fibrous activated carbon, greensand, silica 
sand, neutralizing sand, activated alumina, ion exchange resins, polymeric 
adsorbents, coal, porous plastic medium, porous paper medium, porous 
carbon medium, coalescing filter medium, porous stainless steel medium, 
porous mild steel medium, porous ceramic medium, porous alloy medium, 
bacteriostatic filter medium, or combinations thereof, 
(b) loading a process tank of said apparatus with the regenerating 
chemicals, or flocculating chemicals, or filter aids or said granular 
filter media, 
(c) discharging the contaminated liquid to an influent pipe of said 
apparatus comprising an ultraviolet pretreatment means, a pressure pump, a 
central flow control means, said pressure filter, said process tank, a 
chemical feeder means, a piping system, an ultraviolet post-treatment 
means, compressed air aeration means, air emission control means, flow 
meters, pressure gauges and safety valves, 
(d) selecting either manual operation or automatic operation, 
(e) deciding a desired mode of operation (filtration, backwash, bypass, 
flushing, chemical preparation, recirculation, precoat, rinse, or 
desorption) by dialing either manually or automatically the selected 
operational mode marked on the center flow control which consists of a 
wide-open inlet port, an on-off port to said pressure filter, an on-off 
port from said pressure filter, an on-off outlet port to an effluent 
discharge pipe, an on-off outlet port to said process tank, and an on-off 
outlet port to said waste drain, 
(f) operating said apparatus at the filtration mode by pumping said liquid 
and (dialing the central flow control to "filtration") allowing the on-off 
ports to said process tank and said waste drain to be closed, and all 
other ports of said central flow control means to be open, when the 
ultraviolet pretreatment means and said chemical feeder means are on for 
liquid pretreatment and normal filtration operation, 
(g) or operating said apparatus at the backwash mode by pumping and 
(dialing the central flow control to "backwash") allowing the on-off ports 
to said process tank and said effluent discharge pipe to be closed, and 
all other ports of said central flow control means to be open for 
backwashing said pressure filter, 
(h) or operating said apparatus at the bypass mode by pumping said liquid 
and (dialing the central flow control to "bypass") allowing the on-off 
ports to and from said pressure filter, and to said process tank and said 
waste drain to be closed, and all remaining ports of said central flow 
control means to be open for said liquid to bypass both said pressure 
filter and said process tank and to be discharged by said pump through 
said central flow control means, 
(i) or operating said apparatus at the flushing mode by pumping said liquid 
and (dialing the control flow control to "flushing") allowing the on-off 
ports connecting to said pressure filter, process tank and effluent 
discharge pipe to be all closed, and the remaining ports to be open for 
flushing said central flow control means by said liquid, 
(j) or operating said apparatus at the chemical preparation mode by pumping 
said liquid and (dialing the central flow control to "preparation") 
allowing the on-off ports connecting to said pressure filter, effluent 
discharge pipe and waste drain to be closed, and the remaining ports of 
said control flow control means to be open, for mixing chemical(s) or 
filter aids, or granular filter media, with the influent contaminated 
liquid in said process tank, 
(k) or operating said apparatus at recirculation mode for liquid 
recirculation or media regeneration by pumping said liquid and (dialing 
the central flow control means to "recirculation/precoat" without pushing 
a "precoat" button) allowing the on-off ports connecting to said effluent 
discharge pipe and waste drain to be closed, and the remaining ports to be 
open, 
(l) or operating said apparatus at precoat mode by pumping said liquid, 
(pushing the precoat button and dialing the central flow control means to 
"recirculation/precoat") allowing the on-off ports connecting to said 
effluent discharge pipe and waste drain to be closed, when a filter media 
slurry is being recirculated through said pump, central flow control 
means, pressure filter, central flow control means and process tank for 
precoating said filter media onto a filter septum of said pressure filter, 
(m) or operating said apparatus at special desorption mode by not pumping 
said liquid (pushing the desorption button, and dialing the central flow 
control means to "rinse/desorption") allowing the on-off ports connecting 
to said effluent discharge pipe and said process tank to be closed, the 
on-off ports connecting to said pump and said pressure filter entrance to 
be idled, and all remaining ports of said central flow control means to be 
open, for initially discharging the residual water inside said pressure 
filter, subsequently desorbing (regenerating) the reactive filter media 
inside said pressure filter using compressed air, and finally treating the 
emitted gas from said pressure filter using an air emission control means, 
(n) or operating said apparatus at rinse (purging) mode by pumping said 
liquid and (dialing the central flow control to "rinse/desorption", 
without pushing the "desorption" button) allowing the on-off ports 
connecting to said effluent discharge pipe and said process tank to be 
closed, and all remaining ports of said central flow control means to be 
open, when the chemical feeder means is closed, 
(o) post-treating the filter effluent along said effluent discharge pipe, 
with ultraviolet, ozone, hydrogen peroxide, or hypochlorite, during the 
filtration mode, and 
(q) discharging the post-treated product liquid from the end of said 
effluent discharge pipe. 
While the primary object of this invention is to provide a new and improved 
filtration method, another object of this invention is for the provision 
of a new and improved liquid and gas filtration apparatus comprising the 
following: 
(a) an influent liquid pipe leading a contaminated liquid into an 
ultraviolet pretreatment means of said apparatus, 
(b) said ultraviolet pretreatment means connected to said both influent 
liquid pipe and a process tank for receiving and treating the contaminated 
liquid with ultraviolet and thereby producing an ultraviolet pretreated 
liquid, 
(c) a chemical feeder means connected to said ultraviolet pretreatment 
means and said process tank for feeding chemical, further treating of the 
ultraviolet pretreated liquid, and producing a chemical pretreated liquid, 
or for feeding regenerating chemical, filter aids, or granular filter 
media in slurry form, 
(d) a pump connected to said chemical feeder means and a central flow 
control means for providing energy to move the ultraviolet and/or chemical 
pretreated liquid throughout entire apparatus, 
(e) said central flow control means connected to said pump, said process 
tank, a pressure filter, an effluent discharge pipe and a waste drain, and 
having a handle for manual or automatic dialing, a wide-open influent port 
and multiple on-off ports, for directing a body of liquid from the pump to 
proper flow direction, 
(f) said pressure filter connected to said central flow control means and 
comprising a liquid inlet, a liquid outlet, said filter media for 
purifying the liquid from said central flow control means, a filter septum 
for supporting said filter media, a compressed gas inlet for desorbing and 
regenerating said filter media, a condensate outlet, and a gas outlet, 
(g) said process tank connected to said central flow control means and said 
chemical feeder means for preparing and storing chemicals and filter aids, 
and for pretreating the contaminated liquid, 
(h) said effluent discharge pipe connected to said central flow control 
means for discharging the liquid from said central flow control means, 
(i) said waste drain connected to said central flow control means for 
discharging wastes, 
(j) said ultraviolet post-treatment means connected to said effluent 
discharge pipe for post-treating the liquid from said central flow control 
means, and thereby producing an apparatus effluent (product liquid), 
(k) a final effluent discharge pipe connected to said ultraviolet 
post-treatment means for discharging the apparatus effluent, 
(l) an internal process piping system connecting the influent liquid pipe, 
said ultraviolet pretreatment means, said chemical feeder means, said 
pump, said central flow control means, said pressure filter, said process 
tank, said ultraviolet post-treatment means, said effluent discharge pipe, 
said final effluent discharge pipe, and said waste drain and equipped with 
flow meters, pressure gauges and safety valves, and 
(m) an air emission control means connected to said waste drain and 
comprising an inlet pipe, a tank, a gas inlet, a gas outlet, liquid 
valves, gas valves, a demister pad, a gas mower, prescreens, gas sampling 
ports, liquid outlets, an adsorber, a pressure vacuum gauge, and a venturi 
gas dilution means, for collecting residual liquid and a gas effluent from 
said pressure filter and said central flow control means, and for 
purifying and/or diluting said gas effluent. 
Specifically the air emission control means of this invention is a gas 
filtration apparatus comprising: 
(a) an inlet pipe and a gas inlet for introducing a contaminated gas into 
said apparatus, 
(b) a tank connected to said inlet pipe and having a bottom, side walls, 
and a top thereof as an outside wall of said apparatus, 
(c) liquid valves for discharging accumulated liquid inside said apparatus, 
(d) a prescreen means for preliminary filtering said contaminated gas, 
thereby producing a prescreened gas; said prescreen means further 
comprising a coalescing filter screen, a fiberglass filter screen, a 
fibrous filter screen, or combinations thereof, 
(e) a gas mover connected to said tank for moving said prescreened gas, 
(f) a gas valve and a venturi gas dilution means connected to said gas 
mover for diluting said prescreened gas, thereby producing a diluted gas 
to be discharged into ambient air, 
(g) a gas sampling point connected to said gas mover for collecting said 
prescreened gas for analysis, 
(h) a demister connected to said gas mover for removing moisture from said 
prescreened gas, 
(i) an adsorber connected to said demister for removing volatile and 
radioactive contaminants from said prescreened gas and thereby producing 
an adsorber effluent; said adsorber further comprising an adsorption tank, 
a gas inlet, a gas outlet, adsorbent (virgin granular activated carbon, 
virgin fibrous activated carbon, ion exchange resins, polymeric adsorbent, 
base treated activated carbon, aluminate treated activated carbon, base 
treated polymeric adsorbent, aluminate treated polymeric adsorbent, 
reticulated foam, fiberglass screen, fibrous activated carbon screen, 
coalescing filter screen, or combinations thereof), valves, and pipes, and 
(j) said gas outlet connected to said adsorber for discharging said 
adsorber effluent to the ambient air environment. 
It is yet another object of the subject invention for the provision of a 
new and improved filtration system with ozonation, chlorination, and 
ultraviolet irradiation treating means either upstream or downstream of a 
pressure filter for water purification. The present invention is used for 
removal of not only suspended particles, but also living microorganisms, 
soluble iron, manganese, heavy metals, hardness, volatile organic 
compounds, radioactive gas, odor, and colloidal solids from contaminated 
river water, lake water, groundwater, domestic sewage, industrial process 
liquid, storm run-off, and swimming pool water.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention, as shown in FIGS. 1 to 11, relates to a central 
controlled reactive/regenerative filtration process and apparatus by which 
the water is pretreated or post-treated with ultraviolet, ozone, hydrogen 
peroxide, flocculating chemical, permanganate, and hypochlorite, and by 
which living, non-living, suspended, volatile, radioactive, and dissolved 
contaminants are efficiently removed from water under one of pressurized 
innovative hydraulic patterns shown in FIGS. 1A to 1H. 
Ozonation, ultraviolet, peroxide oxidation, permanganate oxidation, and 
chlorination are the processes involving the use of ozone, ultraviolet, 
hydrogen peroxide, potassium permanganate and sodium (or calcium) 
hypochlorite, respectively. 
The major components of the present invention include an ultraviolet 
pretreatment means 5, a pressure pump 2, a central flow control means 3, a 
pressure filter 4, an ultraviolet post-treatment means 6, a process tank 
11, a chemical feed system (chemical feeder means) 7, an operating valve 
8, a check valve 40, an air emission control means 14, and a pipe line 
system comprising pipes 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L and 11L, 
all shown in FIGS. 2 to 10. 
FIG. 11 illustrates said air emission control means 14 (also see FIG. 10) 
in accordance with the present invention. 
Both said ultraviolet pretreatment means 1 and said ultraviolet 
post-treatment means 5 kill pathogenic legionella as well as other 
pathogenic microorganisms by ultraviolet irradiation which has emerged as 
the best disinfection technology especially suitable for use with 
point-of-entry (POE) devices. 
The multi-purpose chemical feed system (chemical feeder means) 7 with its 
control valve 8 provide additional pretreatment to the contaminated liquid 
Q1 using ozone, hypochlorite (a free chlorine), hydrogen peroxide, 
potassium permanganate, or combinations thereof. With 0.2 mg/l of residual 
ozone, and 0.3 minute of contact time, over 99% of Legionella pneumophila 
was killed. With 0.5 mg/l (in terms of free chlorine) of calcium 
hypochlorite and 1 minute of contact time, again over 99% of Legionella 
pneumophila reduction was achieved. In the case of the present invention, 
calcium hypochlorite in dry tablet form is used for small POE disinfection 
operations and ozone and hydrogen peroxide are used for institutional 
operations. 
Ozone (O.sub.3), potassium permanganate (KMnO.sub.4) or hydrogen peroxide 
(H.sub.2 O.sub.2) is fed through the chemical feed system 7 for removal of 
iron and manganese by conversion of soluble iron and manganese in the 
contaminated liquid Q1 into their insoluble forms, so they can be 
effectively filtered out by the pressure filter 4 in accordance with the 
following chemical reactions: 
EQU soluble divalent ferrous ions+O.sub.3 (or KMnO.sub.4 or H.sub.2 
O.sub.2)=insoluble ferric oxide or soluble ferric ions 
EQU soluble ferric ions+hydroxide ions=insoluble ferric hydroxide 
EQU soluble divalent manganese ions+O.sub.3 (or KMnO.sub.4 or H.sub.2 
O.sub.2)=insoluble manganese oxide 
For a prolonged filtration operation, the pressure filter 4 is completely 
sealed and normally operated under one of three crossflow hydraulic 
conditions: an upward-crossflow (FIGS. 1A and 1B), a downward-crossflow 
(FIG. 1C), or a horizontal crossflow (not shown). The same pressure filter 
4 is technically called a horizontal crossflow filter under horizontal 
crossflow condition, a downward crossflow filter under downward crossflow 
condition, or an upward crossflow filter under upward crossflow condition. 
During normal upward crossflow filtration operation shown in FIGS. 1A, 1B, 
and 2, the filter influent Qi enters said pressure filter 4 at inlet 4A, 
filter effluent Qe exits at filter outlet 4C, and a small volume of 
concentrate Qc exits at another filter outlet 4B. In case the filter 
outlet 4B in FIG. 2 is shut off, the pressure filter 4 is then operated 
under conventional upflow filtration condition. 
The pressure filter 4 of the present invention, shown in FIGS. 1A, 1B, 1C, 
1G and 1I, normally comprises both the granular filter media 4F and at 
least one filter septum (filter element) 4S. In a preferred embodiment, 
porous stainless steel medium, porous ceramic medium, porous plastic 
medium or porous alloy medium is placed inside said pressure filter 4 as 
the filter septum (filter element) 4S for supporting the granular filter 
media 4F which are selected from a group including granular activated 
carbon, chemical treated adsorbent, polymeric adsorbent, granular 
activated alumina, granular metal medium, greensand, neutralizing sand, 
silica sand, coal, diatomaceous earth, manganese dioxide, ion exchange 
resins (cation exchange resins, anion exchange resins), bacteriostatic 
filter medium (silver impregnated granular activated carbon, iodinated 
resin), or combinations thereof. Several selected examples are given below 
for illustration of the treatment efficiency of said pressure filter 4 
when reactive filter media are used. The porous plastic medium is selected 
from a group including polyethylene, nylon, PVC, or combinations thereof. 
Inside said pressure filter 4, the filter element 4S accepts both reactive 
and non-reactive granular filter media either as a precoat media (FIGS. 
1A, 1B, 1C, 1D, and 1G) or fixed filter bed media (FIG. 1I). Inside said 
pressure filter 4, the reactive granular filter media 4F are precoated on 
the surface of said filter element (filter septum) 4S with more than one 
layer of media and with coarser media to be coated on the outside layer. 
Besides, the filter element (filter septum) 4S is wrapped up with an 
optional porous expandable elastic sleeve 4SF before being precoated for 
enhancement of precoat filtration operation (FIGS. 1A and 1B). 
The reactive granular filter media 4F adapted by the present invention are 
packed in the pressure filter 4 either as a fixed filtration bed (FIGS. 1G 
and 1I) or as a precoat filtration bed (FIGS. 1A, 1B, and 1C). The fixed 
bed filtration is operated either in the presence or in the absence of 
reactive granular filter media. 
The first example of reactive granular filter media to be used in said 
pressure filter 4 is the silver impregnated granular activated carbon 
(GAC), which is designed to slowly release biocide (i.e. low concentration 
of silver ions) into the pathogen-carrying water. The silver impregnated 
GAC maintains a constant residual concentration of silver ions regardless 
of the presence of microorganisms; therefore it is called constant-release 
disinfectant/adsorbent. The silver impregnated GAC not only destroys 
pathogenic microorganisms, but also removes toxic dissolved organics (such 
as trihalomethanes, phenols, formaldehydes, etc.), toxic dissolved 
inorganics (such as lead, excessive chlorine, hydrogen sulfide, etc.) and 
insoluble suspended solids. Under normal tap water supply conditions that 
trihalomethanes, coliform bacteria, and lead concentrations in the tap 
water (i.e. influent liquid to said apparatus) will not be as high as 200 
ppb, 135 coliform colonies/100 ml, and 150 ppb, respectively. The pressure 
filter 4 containing the silver impregnated GAC reduces trihalomethanes, 
coliform bacteria and lead to 6 ppb, 0 colonies/100 ml and 17 ppb, 
respectively. The silver impregnated GAC also removes bad taste, odor, 
hydrogen sulfide from water. The virgin GAC can also be adapted for 
removal of toxic organics, heavy metals, bad taste, odor and hydrogen 
sulfide, but not for disinfection. 
Any granular activated carbons (virgin GAC and the silver impregnated GAC) 
as well as fibrous activated carbons (FAC) adopted by the present 
invention also remove toxic radioactive radon gas from a contaminated 
liquid, such as groundwater. 
The following are physical-chemical reactions of the present invention for 
removal of volatile organic compounds (VOCs) and radioactive radon gas 
from a contaminated liquid, and for regeneration of the spent GAC (either 
a virgin GAC or a silver impregnated GAC or a base-treated GAC) for reuse, 
all using the present invention's apparatus: 
EQU GAC+contaminated liquid containing VOCs and radon=VOCs and radon 
impregnated spent GAC+purified liquid 
EQU VOCs and radon impregnated spent GAC+compressed gas=regenerated GAC+gas 
effluent containing VOCs and radon 
EQU regenerated GAC+contaminated liquid containing VOCs and radon=VOCs and 
radon impregnated GAC+purified liquid 
The second reactive granular filter media to be used in the pressure filter 
4 are the iodinated, strong-base resins that release iodine upon demand to 
microorganisms in water. Bacteria including Staphylococcus aureus, E. 
Coli, Pseudomonas aeruginosa, Salmonella pullorum each at the 
concentration of 2.3.times.10.sup.4 colonies/ml, and viruses including 
Polyoma, Newcastle Disease, Poliovirus, each the concentration of 
2.0.times.10.sup.4 plaque forming units per milliliter (pfu/ml) are 
totally disinfected after the pathogen-carrying water is contacted with 
the iodinated strong base resins. 
The third reactive granular filter media to be used in the pressure filter 
4 is similar to the medium described in the U.S. Pat. No. 4,642,192, 
issued Feb. 10, 1987 to Don E. Heskett, and called brass KDF. Heskett's 
filter medium works on the redox principle of dissimilar metals and lasts 
from ten to twenty times longer than GAC for removal of excessive amount 
of chlorine from tap water, or for removal of algae from reservoir water 
or swimming pool water. The brass making up the KDF medium contains 
approximately: 59.2% copper, 35.2% zinc, 2.5% lead and 0.2% iron by 
weight. The brass KDF is commonly used in solid granular form as the 
filter medium in conventional filters, but it is used in porous cartridge 
form as one of the septums in the pressure filter 4 of the present 
invention. 
The fourth reactive granular filter medium suitable for use in the pressure 
filter 4 is the manganese greensand from the mineral glauconite, also 
known as Ferrosand, which operates on the chemical principle of oxidation 
and reduction and the catalytic effect of manganese oxides, for removal of 
excessive soluble iron and manganese from water, without the need for long 
reaction times and/or high pH levels. The pressure filter 4 is installed 
either vertically or horizontally. The greensand is not only reactive, but 
also regenerative. About 2 oz. of potassium permanganate is required for 
regeneration of 1 cubic foot of greensand for its reuse. Like other 
granular filter media, greensand also removes insoluble suspended 
contaminants. In addition, it removes hydrogen sulfide up to 5 mg/l. 
Assuming Z represents the black manganese greensand granules, the 
following two chemical reactions show how the soluble manganese Mn.sup.+2 
and soluble iron Fe.sup.+2 are removed by the pressure filter 4: 
EQU Z*MnO.sub.2 +Mn.sup.+2 +Fe.sup.+2 =Z*Mn.sub.2 O.sub.2 O.sub.3 +MnO.sub.2 
+Fe.sup.+3 
EQU Fe.sup.+3 +3OH (hydroxide ions)=Fe(OH).sub.3 
Both MnO.sub.2 and Fe(OH).sub.3 with underlines are insoluble precipitates 
which are removed by filtration and backwash. The following is the 
chemical reaction showing how the spent manganese greensand is regenerated 
with potassium permanganate KMnO.sub.4 solution: 
EQU Z*Mn.sub.2 O.sub.3 +KMnO.sub.4 =Z*MnO.sub.2 +K.sup.+ 
The regenerated greensand Z*MnO.sub.2 can then be reused. 
Manganese dioxide is a reactive granular filter medium similar to 
greensand, and is the fifth filter medium for use in the pressure filter 4 
as the filter media 4F. Adsorption of many toxic soluble heavy metals 
(nickel, cadmium, zinc, lead, copper, silver, and selenium) onto manganese 
has been scientifically established. 
Activated alumina having a formula of (Al.sub.2 O.sub.3)n*H.sub.2 SO.sub.4 
contains mainly aluminum oxides and is the sixth reactive granular filter 
medium adopted by the pressure filter 4 of the present invention. 
Activated alumina when packed in said pressure filter 4 as the filter 
media 4F is very effective for controlling fluoride (F) in drinking water. 
In general, it is necessary to control and maintain the concentration of 
fluoride below 1 mg/l. The following is the chemical reaction for fluoride 
removal: 
EQU (Al.sub.2 O.sub.3)n*H.sub.2 SO.sub.4 +2F.sup.- =(Al.sub.2 
O.sub.3)n*2HF+SO.sub.4.sup.-2 
This filter medium, activated alumina, is also of a regenerative type. The 
spent activated alumina is regenerated with sulfuric acid H.sub.2 SO.sub.4 
or aluminum sulfate Al.sub.2 (SO.sub.4).sub.3 for reuse: 
EQU (Al.sub.2 O.sub.3)n*2HF+SO.sub.4.sup.-2 =(Al.sub.2 O.sub.3)n*H.sub.2 
SO.sub.4 +2F.sup.- 
Between 1 to 2 mg F.sup.- are removed per each gram of activated alumina, 
depending the particle size of the filter medium in the range of 0.6 to 5 
mm at pH=8. Soluble cations that can be removed by activated alumina 
include uranium, zirconium, cerium, iron, titanium, mercury, lead, copper, 
silver, zinc, cobalt, nickel, thallium, and manganese. Soluble anions that 
can be removed by activated alumina include AsO.sub.4.sup.-3, 
PO.sub.4.sup.-3, C.sub.2 O.sub.4.sup.-2, F.sup.-, SO.sub.3.sup.-2, 
Fe(CN).sub.6.sup.-4, CrO.sub.4.sup.-2, S.sub.2 O.sub.3.sup.-2, 
Fe(CN).sub.6.sup.-3, Cr.sub.2 O.sub.7.sup.-2, NO.sub.2.sup.-, CNS.sup.-, 
I.sup.-, Br.sup.-, Cl.sup.-, NO.sub.3.sup.-, MnO.sub.4.sup.-, 
CIO.sub.4.sup.-, CH.sub.3 COO.sup.- and S.sup.-2. Removal of dissolved 
organics by activated alumina is improved by preoxidation with ozone or 
hydrogen peroxide, of this invention. 
The neutralizing sands including Calcite and magnesium oxide (known as 
Corosex) are the seventh and the eighth type of reactive granular filter 
media to be packed in said pressure filter 4 for the purpose of filtration 
as well as neutralization. Calcite is a crushed and screened white marble 
sand which is inexpensively used to neutralize acidic or low pH waters to 
produce a neutral non-corrosive product water. In theory, acidic water on 
contact with Calcite slowly dissolves the calcium carbonate filter media 
thus raises the pH. Calcite contains 95% of CaCO.sub.3 and 3% of 
MgCO.sub.3. The service flow rate is about 3 to 6 gpm/ft.sup.2. 
Another neutralizing sand, magnesium oxide, contains about 97% MgO, and is 
grayish white. Magnesium oxide, or Corosex, is specially processed hard, 
beadlike filter media adapted for use in said pressure filter 4 to 
neutralize extremely high acidity by chemical reaction, in turn, 
increasing the pH value of water. Downflow filtration operation is 
satisfactory on waters with a hardness of less than 5 gpg, or where it is 
combined with Calcite at a ratio of 50%--50%. Upflow filtration operation 
is generally recommended with hardness exceeding 5 gpg to prevent 
cementing of the filtration bed inside said pressure filter 4. The service 
rate of this reactive granular filter medium can be as high as 5 
gpm/ft.sup.2. 
High capacity cation exchange resins are the ninth type of reactive 
granular filter media which are used as the filter media 4F inside said 
pressure filter 4 for removal of cationic soluble metals, calcium 
hardness, magnesium hardness, and cationic organic surfactants. Assuming E 
represents the fixed portion of the cation exchange resin granules, 
M1.sup.+, M2.sup.+2 & M3.sup.+3 represent monovalent, divalent and 
trivalent, respectively, of soluble heavy metals (Zn.sup.+2, Cu.sup.+2, 
Ag.sup.+, Ni.sup.+2, Se.sup.+2, Cr.sup.+3, Pb.sup.+2, Fe.sup.+3, 
Fe.sup.+2, Mn.sup.+2, etc.), Ca.sup.+2 represents calcium hardness, 
Mg.sup.+2 represents magnesium hardness, H.sup.+ represents hydrogen ion, 
and T.sup.+ represents soluble cationic toxic organics, the removal 
reactions are as follows: 
EQU E*H (cation exchange resin)+M1.sup.+ =E*M1 (spent cation exchange 
resin)+H.sup.+ 
EQU 2E*H (cation exchange resin)+M2.sup.+2 =2E*0.5M2 (spent cation exchange 
resin)+2H.sup.+ 
EQU 3E*H (cation exchange resin)+M3.sup.+3 =3E*0.333M3 (spent cation exchange 
resin)+3H.sup.+ 
EQU 4E*H (cation exchange resin)+Ca.sup.+2 +Mg.sup.+2 
=2E*0.5Ca+2E*0.5Mg+4H.sup.+ 
EQU E*H (cation exchange resin)+T.sup.+ =E*T (spent cation exchange 
resin)+H.sup.+ 
E*H in the above equations represents the cation exchange resin in hydrogen 
form; so E*H releases H.sup.+ in low concentration after reaction. In case 
the cation exchange resin in sodium form E*Na is used in replacement of 
E*H, Na.sup.+ (instead of H.sup.+) will be released to water in the above 
equations; the spent cation exchange resins will be the same, however. 
All spent cation exchange resins designated above can be effectively 
regenerated by using highly concentrated acid or brine (sodium chloride; 
NaCl) solutions as follows: 
EQU E*M1+H.sup.+ (regenerant) =E*H (regenerated cation exchange resin)+M1.sup.+ 
EQU 2E*0.5M2+2H.sup.+ (regenerant) =2E*H (regenerated cation exchange 
resin)+M2.sup.+2 
EQU 3E*0.333M3+3H.sup.+ (regenerant) =3E*H (regenerated cation exchange 
resin)+M3.sup.+3 
EQU 2E*0.5Ca+2E*0.5Mg+4H.sup.+ (regenerant) =4E*H (regenerated cation exchange 
resin)+Ca.sup.+2 +Mg.sup.+2 
EQU E*T+H.sup.+ (regenerant) =E*H (regenerated cation exchange resin)+T.sup.+ 
where H.sup.+ ions are supplied by highly concentrated acid. All E*H on the 
right-hand side of equations are regenerated cation exchange resins in 
hydrogen form, and ready for reuse in said pressure filter 4; and 
M1.sup.+, M2.sup.+2, M3.sup.+3, Ca.sup.+2, Mg.sup.+2 and T.sup.+ are 
highly concentrated rejects ready to be discharged for waste disposal. 
In case highly concentrated brine NaCl is used for regeneration of spent 
cation exchange resins, NaCl will provide Na.sup.+ ions (instead of 
H.sup.+ ions) for regeneration. The regenerated cation exchange resins 
will be in sodium form E*Na (instead of E*H) and M1.sup.+, M2.sup.+2, 
M3.sup.+3, Ca.sup.+2, Mg.sup.+2 and T.sup.+ are also produced in the 
reject solutions. Accordingly, the cation exchange resins are reactive as 
well as regenerative granular filter media. 
High capacity anion exchange resins belong to the tenth type of reactive 
granular filter media which are used inside said pressure filter 4 aiming 
at removal of anionic soluble impurities and toxics, including but not 
being limited to: AsO.sub.4.sup.-3, PO.sub.4.sup.-3, C.sub.2 
O.sub.4.sup.-2, F, SO.sub.3.sup.-2, Fe(CN).sub.6.sup.-4, CrO.sub.4.sup.-2, 
S.sub.2 O.sub.3.sup.-2, SO.sub.4.sup.-2, Fe(CN).sub.6.sup.-3, Cr.sub.2 
O.sub.7.sup.-2, NO.sub.2.sup.-1, CNS.sup.-, I.sup.-, Br.sup.-, Cl.sup.-, 
NO.sub.3.sup.-, MnO.sub.4.sup.-, CIO.sub.4.sup.-, CH.sub.3 COO.sup.-, and 
S.sup.-2. The above are the most common impurities in tap water. Examples 
are presented below showing how they are removed by anion exchange resin 
in hydroxide form E*OH, and how the spent anion exchange resins are 
regenerated by strong alkaline solution such as sodium hydroxide NaOH. 
A1.sup.-, A2.sup.-2 and A3.sup.-3 now represent soluble monovalent, 
divalent, and trivalent, respectively, of the above anionic 
impurities/toxics. E represents the fixed portion of the anion exchange 
resin granules, and E*OH is the anion exchange resin in hydroxide form. 
EQU E*OH (anion exchange resin)+A1.sup.- =E*A1 (spent anion exchange 
resin)+OH.sup.- 
EQU 2E*OH (anion exchange resin)+A2.sup.-2 =2E*0.5A2 (spent anion exchange 
resin)+20H.sup.- 
EQU 3E*OH (anion exchange resin)+A3.sup.-3 =3E*0.333A3 (spent anion exchange 
resin)+30H.sup.- 
As shown in the above three equations, hydroxide ions OH.sup.- are released 
in low concentration to the treated water after anionic impurities/toxics 
are removed by the anion exchange resins. 
When the anion exchange resins are exhausted and spent, they are due for 
regeneration with highly concentrated sodium hydroxide NaOH solution (or 
other concentrated base solution, such as potassium hydroxide KOH) so the 
above three chemical equations can be forced to reverse: 
EQU E*A1+OH.sup.- (regenerant) =E*OH (regenerated anion exchange 
resin)+A1.sup.- 
EQU 2E*0.5A2+20H.sup.- (regenerant) =2E*OH (regenerated anion exchange 
resin)+A2.sup.-2 
EQU 3E*0.333A3+30H.sup.- (regenerant) =3E*OH (regenerated anion exchange 
resin)+A3.sup.-3 
where A1.sup.-, A2.sup.-2 and A3.sup.-3 are the rejects in high 
concentration but low volume, ready to be discharged for waste disposal. 
Diatomaceous earth (DE) is the non-reactive granular filter media commonly 
used in all conventional precoat filters for removal of non-living, 
insoluble, suspended contaminants from water. The process and apparatus of 
this invention involves the use of reactive granular filter media for 
removal of living, non-living, dissolved and suspended contaminants from 
water; besides, most of reactive granular filter media are regenerative. 
DE is adapted as the filter aid or filler in the present invention for 
filtration operation and cost-saving. 
The present invention also relates to the adoption of polymeric adsorbents 
as the filter media 4F in the pressure filter 4 for removal of volatile 
organic compounds (VOCs) and radioactive radon gas from a contaminated 
liquid. Polymeric adsorbents are the man-made products with many 
micropores. The following are physical-chemical reactions for the present 
invention to remove both volatile and radioactive contaminants from a 
contaminated liquid using polymeric adsorbents (PA) and to regenerate the 
spent polymeric adsorbents for reuse: 
EQU PA+contaminated liquid containing VOCs and radon =VOCs and radon 
impregnated spent PA+purified liquid 
EQU VOCs and radon impregnated spent PA+compressed gas =regenerated PA+gas 
effluent containing VOCs and radon 
EQU regenerated PA+contaminated liquid containing VOCs and radon =VOCs and 
radon impregnated PA+purified liquid 
The adsorber 25 of this invention shown in FIG. 11 contains adsorbent and 
is used for purification of said gas effluent containing VOCs and radon 
gas which is released during the process of GAC regeneration or the 
process of PA regeneration in a desorption mode (FIG. 10), in accordance 
with the following physical-chemical reactions: 
EQU adsorbent+gas effluent containing VOCs and radon =VOCs and radon 
impregnated spent adsorbent+purified gas effluent 
Said purified gas effluent 12A shown in FIG. 11 can then be directly 
discharged into ambient air environment. The VOCs and radon impregnated 
spent adsorbent is solidified by cement and/or polymeric solidifying agent 
for final disposal in a sanitary landfill. Alternatively, said gas 
effluent containing VOCs and radon can be released without hazard into the 
ambient air environment if diluted by a venturi dilution means 40 (FIG. 
11) to a concentration deemed safe by regulating agencies, so said 
adsorbent in said adsorber 25 is not needed. Still alternatively said 
adsorber 25 containing said adsorbent is adopted for gas purification, and 
the spent adsorbent is collected for commercial regeneration or commercial 
disposal by a licensed environment firm. 
Said adsorbent in said adsorber 25 is chosen from a group comprising 
fibrous activated carbon (FAC), granular activated carbon (GAC), polymeric 
adsorbent (PA), chemical treated adsorbent, base treated GAC, base treated 
FAC, coalescing filter medium, porous paper filter medium, porous carbon 
filter medium, porous fiber glass filter medium, or combinations thereof. 
Said base is sodium hydroxide, potassium hydroxide, calcium hydroxide, 
sodium aluminate, or combinations thereof. 
The reactive granular filter media 4F adapted by the present invention are 
packed in the pressure filter 4 either as a fixed filtration bed or as a 
precoat filtration bed, as shown in FIGS. 1A-1I either in the presence or 
in the absence of diatomaceous earth (DE). 
The central controlled filtration system with pretreatment and 
post-treatment, as in the case of the present invention, has nine 
operational modes: filtration (FIG. 2), backwash (FIG. 3), bypass (FIG. 
4), flushing (FIG. 5), chemical preparation (FIG. 6), recirculation (FIG. 
7), precoat (FIG. 8), rinse (FIG. 9) and desorption (FIG. 10), which each 
is chosen by manually or automatically dialing the operational mode marked 
on the central flow control means 3. 
The central flow control 3 consists of a wide-open inlet port 4P, an on-off 
port 5P to said pressure filter 4, an on-off port 6P from said pressure 
filter 4, an on-off port 8P to said process tank 11, and an on-off outlet 
port 7P to said waste drain 7L & 10L, and is clearly marked for the modes 
of operation including at least filtration, backwash, bypass, flushing, 
preparation, recirculation/precoat, and rinse/desorption. 
More than one chemical feeder means 7 and valves 8 can be provided to the 
apparatus of the present invention. 
The entire apparatus of the present invention is of modular design, each 
comprising a piping system 1L-10L, a chemical feed system 7, a pump 2, a 
central flow control means 3, a pretreatment means 5 and a post-treatment 
means 6. One or more than one modules (each having different reactive 
granular filter media) is installed together for a specific water 
treatment application. Since there is only one central flow control means 
for each module, the automation is accomplished mechanically and 
electrically, although manual operation is also very simple and 
satisfactory. 
The chemical feed system 7 and the process tank 11 feeds and mixes, 
respectively, reactive granular filter media during precoat operation, 
shown in FIG. 8; while the same chemical feed system 7 and the process 
tank 11, feeds and mixes, respectively, the chemicals for regeneration of 
filter media inside said pressure filter 4 during chemical preparation 
operation shown in FIG. 6. The chemical for regeneration of cation 
exchange resins is sodium chloride (or an acid) which is fed and processed 
by said chemical feed system 7 and said process tank 11, respectively; 
while the chemical for regeneration of anion exchange resins is sodium 
chloride (or a base) which is also fed and processed by said chemical feed 
system 7 and said process tank 11, respectively. 
The simplicity of the improved liquid filtration is fully illustrated in 
FIG. 1A to 11 by its minimum number of required valves (one central flow 
control means and a few chemical feed calibration valves as the minimum) 
although addition of more valves will not hinder the filtration operation 
of the present invention. 
Detailed description of operational features of the preferred embodiment is 
illustrated in FIGS. 2 to 10 inclusive which are a set of schematic 
diagrams of the present invention when applied to liquid filtration under 
different modes of operations. 
FIGS. 1A through 1I inclusive illustrate various designs of said pressure 
filter 4 in accordance with this invention. 
FIG. 1A presents the flow pattern and inside structure of said pressure 
filter 4 which is assembled and operated as an upward crossflow filter 
with an elastic monofilament sleeve 4SF covering the outside of said 
filter septum 4S. The filter media 4F is precoated on said sleeve 4SF, by 
said precoat mode shown in FIG. 8. During said filtration mode of 
operation shown in FIGS. 1A and 2, the rotating flow pattern 75 inside 
said pressure filter 4 allows a longer filtration run in comparison with a 
similar filtration operation (FIG. 1B) without said rotating flow pattern 
75. 
FIG. 1B represents another flow pattern and inside structure of said 
pressure filter 4 which is also assembled and operated as an upward 
crossflow filter with an elastic monofilament sleeve 4SF covering the 
outside of said filter septum 4S to support said filter media 4F, but 
without a rotating flow pattern inside said pressure filter 4. 
FIG. 1C illustrates a situation when said pressure filter 4 is operated as 
a downward crossflow filter without an elastic monofilament sleeve and 
rotating flow pattern. The filter media 4F is precoated onto said filter 
septum 4S directly for the purpose of liquid filtration. 
FIG. 1D illustrates an alternative of said pressure filter 4 comprising 
multiple cells of filter cartridges 61 and a filter bag 62 containing 
reactive filter media, such as granular activated carbon, polymeric 
adsorbent, reticulated foam, neutralizing sand, manganese oxides, ion 
exchange resin, or combinations thereof. The pressure filter 4 shown in 
FIG. 1D is designed for fast and easy replacement of filter cartridges 61 
and said filter bag 62. The entire pressure filter 4 can be disassembled 
and reassembled in minutes. Chambers 68, 69, and 70 are empty spaces for 
uniform fluid distribution. Although the pressure filter 4 shown in FIG. 
1D is a downflow filter, it can also be operated as an upflow filter if 
the direction of liquid flow is reversed. Said filter cartridges 61 can be 
of prefabricated disposal type requiring no precoating and backwashing, or 
of reusable type comprising a filter septum, an optional monofilament 
sleeve, and filter media, and requiring precoating and backwashing. 
FIG. 1E is a downflow modular pressure filter 4 comprising multiple filter 
modules 58, 59 and 60, packed with reactive and non-reactive filter media. 
Again, the entire pressure filter 4 can be disassembled and reassembled in 
minutes because each module can be taken apart individually and easily for 
replacement or regeneration. Chambers 68 and 69 are empty spaces for 
uniform liquid distribution. Said pressure filter 4 can be operated as an 
upflow filter if the liquid flow is reversed, and requires no precoating 
or backwashing. 
FIG. 1F features easy drop-in filter bag 56 to be mounted inside said 
pressure filter 4, and supported by a filter septum 4S. Said drop-in 
filter bag 56 can be used alone for filtration, or be filled with reactive 
and non-reactive filter media 57 described previously. As a typical 
example, when said drop-in filter bag 56 is packed with hydrophobic 
reticulated foam as said filter media 57, the pressure filter 4 becomes 
effective for removal of oil and grease from water. Although FIG. 1F shows 
only one drop-in filter bag 56 in said pressure filter 4, there can be 
more tan one drop-in filter bags installed in said pressure filter 4. 
FIG. 1G is an alternative upflow pressure filter 4 comprising filter septum 
4S, filter media 4F, fluid distribution chamber 68 and 69, and filter bags 
66 and 67. Said filter bags 66 and 67 further contain reactive and 
non-reactive filter media described previously. Said filter media 4F can 
be precoated and backwashed. Said pressure filter 4 shown in FIG. 1G can 
be a downflow filter if it is positioned upside down. 
FIG. 1H is another alternative pressure filter 4 comprising a filter bag 63 
connected to a filter entrance 4A and said pipe 5L, a second filter bag 
64, a filter septum 4S, a fluid distribution chamber 68, and a filter exit 
4C. Other components of said pressure filter 4 have been defined 
previously. A quick disconnect coupling at said filter entrance 4A is 
featured for removing and attaching said filter bag 63. 
All bag filters, including drop-in filter bags can have a choice of 
different micron bags ranging from 1 to 1000 microns. 
FIG. 1I is an improved downflown pressure filter 4 comprising a filter 
entrance 4A, fluid distribution chambers 68 and 69, filter media 4F, a 
filter septum 4S, a concentrate outlet 4B, and a filter exit 4C. Said 
filter media 4F can be of permanent type requiring periodical backwashing 
or precoat type requiring both periodical backwashing and precoating. 
Accordingly, said pressure filter 4 is completely sealed and has means for 
packaging said pressure filter 4 with disposable filter cartridges, 
replaceable filter bags, modular filters, drop-in filter bags, permanent 
filter septum, elastic monofilament sleeve, filter media, means for 
receiving and existing liquid, means for desorption, means for liquid 
distribution, means for concentrate discharge, or combinations thereof. 
Said pressure filter 4 also has means for operating said pressure filter 
means as a crossflow filter (with or without rotating flow; with or 
without elastic monofilament sleeve; downflow, upflow or horizontal flow; 
with or without precoat), or a conventional filter (upflow or downflow). 
Said filter septum 4S (FIGS. 1A-1I) is made of porous stainless steel, mild 
steel, plated steel, alloy, ceramic, glass, fiberglass, or plastic 
(polyethylene, nylon, CPVC, PVC, polypropylene) medium, or combinations 
thereof. 
As a brief summary, the reactive and non-reactive filter media 4F (FIGS. 
1A-1I) of this invention is selected from a group including granular metal 
medium, manganese dioxide, diatomaceous earth, regular granular activated 
carbons, bacteriostatic filter medium (silver impregnated granular 
activated carbon or iodinated resin), granular activated alumina, ion 
exchange resins (cation exchange resins, or anion exchange resins), green 
sand, neutralizing sand, silica sand, coal, polymeric adsorbent, 
reticulated foam, fibrous activated carbon, coalescing filter medium, or 
combinations thereof. The chemical to be adopted by this invention is a 
regenerating chemical (potassium permanganate, sodium chloride, sodium 
iodide), an acid, a base, a disinfectant (ozone, hypochlorite, chlorine), 
a filter aid, a precoat chemical (reactive granular filter media, 
diatomaceous earth), a flocculating chemical (aluminum sulfate, aluminum 
chloride, ferric sulfate, ferric chloride, poly aluminum chloride, poly 
ferric chloride, sodium aluminate, calcium hydroxide, calcium oxide, 
polyelectrolyte), or combinations thereof. 
The process tank 11 of this invention is operated as a sequencing batch 
sedimentation reactor, a sequencing batch flotation reactor, a continuous 
flocculation-sedimentation clarifier, or a continuous 
flocculation-flotation clarifier. 
Referring to FIG. 2 for said filtration mode of operation, the influent 
liquid Q1 with ultraviolet pretreatment means 5 and chemical pretreatment 
is pumped by a pump 2, through an influent pipe 1L, 2L, 3L and 4L to a 
central flow control means 3, from which the pretreated influent liquid Qi 
goes to a pressure filter 4 through pipe 5L for treatment during the 
filtration mode. When operating said apparatus at the filtration mode by 
dialing the central flow control means 3 to "filtration" (not shown), the 
on-off ports 8P and 9P to said process tank 7 and said waste drain 9L, 
respectively, are to be closed, and all other ports 4P, 5P, 6P and 7P of 
said central flow control means 3 are open. The pressure filter 4 which is 
completely sealed during filtration operation, purifies said pretreated 
influent liquid Qi and returns the filter effluent Qe to said central flow 
control means 3 through pipe 6L before its being discharged to pipe 7L for 
the ultraviolet post-treatment means 6. The post-treated liquid is the 
product liquid 10 from the effluent pipe 10L. The on-off valve 4B of said 
pressure filter 4 is on for discharge of concentrate Qc in small 
volumetric rate for the crossflow operation, and is off for the 
non-crossflow operation. 
Referring FIG. 3 for said backwash mode of operation, the pressure filter 4 
which is completely sealed during filter backwash, receives reversed 
influent liquid Q1 flow from said pump 2 and said central flow control 
means 3, through pipes 1L, 2L, 3L, 4L and 6L, self-cleans the granular 
filter media inside of said pressure filter 4 and returns the backwash 
wastewater Qb to said central flow control means 3 before its being 
discharged to a waste drain 9L as the waste 9. When operating said 
apparatus at the backwash mode by pumping and dialing the central flow 
controls to "backwash" (not shown), the on-off ports 8P and 7P to said 
process tank 11 and said discharge pipe 7L, respectively, are closed, and 
all other ports 4P, 5P, 6P and 9P of said central flow control means 3 are 
open. The on-off valves 4B and 8 are closed. 
Referring to FIG. 4 for said bypass mode of operation, the central flow 
control means 3 receives said influent liquid Q1 from said pump 2 and 
discharges said influent liquid Q1 as the product liquid 10 directly 
during the bypass mode of operation. When operating said apparatus at the 
bypass mode by pumping and dialing the central flow control to "bypass" 
(not shown), the on-off ports 5P and 6P to and from said pressure filter 
4, and the on-off ports 8P and 9P to said process tank 11 and said waste 
drain 9L are closed, and all remaining ports 4P and 7P of said central 
flow control means 3 are open. It is a direct bypass if the influent 
liquid Q1 is not pretreated by ultraviolet pretreatment unit 5, and 
chemical feed system 7 and not post treated by ultraviolet post-treatment 
means 6. It is a bypass of filtration if the influent liquid Q1 is 
pretreated and/or post-treated, except not filtered. 
Referring to FIG. 5, the central flow control means 3 receives said 
influent liquid Q1 from said pump 2 and wastes said influent liquid Q1 
immediately to said waste drain 9L during the flushing mode of operation. 
The influent Q1 is not pretreated. When operating said apparatus at the 
flushing mode by pumping and dialing the control flow control means 3 to 
"flushing" (not shown), the on-off ports 5P, 6P, 7P, and 8P connecting to 
said pressure filter 4, process tank 11 and discharge pipe 7L are all 
closed, and the remaining ports 4P and 9P are open. 
Referring to FIG. 6, the central flow control means 3 receives said 
influent liquid Q1 containing chemical from chemical feed system 7 and 
from said pump 2, discharges said influent liquid Q1 containing chemical 
to said process tank 11 for chemical preparation during the preparation 
mode of operation. The chemical is fed to the influent liquid Q1 through 
the chemical feed system 7 and valve 8. The source of influent liquid Q1 
is discontinued when there is enough liquid, and the valve 8 is closed 
when there is enough chemical for chemical preparation. When operating 
said apparatus at the chemical preparation mode by pumping and dialing the 
central flow control means 3 to "preparation" (not shown), the on-off 
ports 5P, 6P, 7P and 9P connecting to said pressure filter 4, liquid 
discharge pipe 7L and waste drain 9L are closed and the remaining ports 4P 
and 8P of said control flow control means 3 are open. 
Referring to FIG. 7, the central flow control means 3 receives the effluent 
Q11 from process tank 11, through pipes 11L, 2L, 3L, 4L and pump 2, 
discharges said process tank effluent Q11 to said pressure filter 4 
through normal filter inlet 4A for regeneration of filter medium, and then 
receives the pressure filter effluent Q4 for recirculation to said process 
tank 11 during the recirculation mode of operation. When operating said 
apparatus at recirculation mode by pumping and dialing the central flow 
control means 3 to "recirculation/precoat I," (not shown) but not pushing 
the precoat I button (not shown), the on-off ports 7P and 9P connecting to 
said liquid discharge pipe 7L and waste drain 9L, respectively, are 
closed, and the remaining ports 4P, 5P, 6P and 8P are open. 
Referring to FIG. 8, when applicable, the central flow control means 3 
receives both said process tank effluent Q11 and the precoat slurry Q7 for 
precoating said pressure filter 4 during the precoat mode of operation. 
The pressure filter effluent Q4 returns to said process tank 11 through 
said central flow control means 3. Both the influent liquid Q1 and the 
precoat slurry Q7, will be shut-off when there are enough liquid and 
precoat for the precoating operation. When operating said apparatus at 
said precoat mode by pumping, pushing the precoat button (not shown), and 
dialing the central flow control means 3 to "recirculation/precoat" (not 
shown), the on-off ports 7P and 9P connecting to said liquid discharge 
pipe 7L and said waste drain 9L, respectively, are closed, and the 
remaining on-off ports 4P, 5P, 6P and 8P are open, when the filter media 
slurry is being recirculated through said pump 2, central flow control 
means 3, pressure filter 4, central flow control means 3, and process tank 
11, for precoating said filter media onto said pressure filter 4. 
Referring to FIG. 9, when applicable, the central flow control means 3 
receives said influent liquid Q1, discharges it to said pressure filter 4 
for rinsing its filter media and wasting the rinse water Q4 from said 
pressure filter 4 to said waste drain 9L, during the rinse mode of 
operation. When operating said apparatus at rinse (purging) mode by 
pumping and dialing the central flow control to "rinse/desorption" (not 
shown), but not pushing the desorption button (not shown), the on-off 
ports 7P and 8P connecting to said liquid discharge pipe 7L and process 
tank 11, respectively, are closed, and all remaining ports 4P, 5P, 6P and 
9P of said central flow control means 3 are open, when the on-off valve 8 
of chemical feeder means 7 is closed. 
Referring to FIG. 10 for said desorption mode of operation, when 
applicable, the pump 2 stops pumping and the central flow control means 3 
is dialed to "rinse/desorption" mode (not shown), and a desorption button 
(not shown) is pushed, allowing the on-off ports 7P, 8P, 5P, and 4P, 
connecting to said second effluent discharge pipe 7L, said process tank 
11, said pressure filter 4 entrance, and said pump 2, respectively, to be 
closed, and the remaining ports 6P and 9P of said central flow control 
means 3 to be open, for initially discharging the residual water inside 
said pressure filter 4, subsequently desorbing (regenerating) the reactive 
filter media 4F using compressed gas 12 and finally purifying the emitted 
gas from said pressure filter 4 using an air emission control means 14 
(FIG. 10). Said air emission control means 14 in FIG. 10 is a tank 14 
shown in FIG. 11 and comprises said waste drain pipe 9L leading said 
residual water and said emitted gas into said air emission control means: 
three prescreens 45, 46, and 47 for preliminary gas purification, a 
demister pad 22 for removal of moisture from said emitted gas 9G, a 
venturi gas dilution means 4D for diluting said emitted gas 9G, a gas 
mover 23 for moving said emitted gas 9G, an inlet gas sampling port 24 for 
sampling and analysis, an adsorber 25 for gas purification, an outlet gas 
sampling port 26 for sampling and analysis, and two liquid outlets 29A and 
29B. In desorption operation, initially, the residual water inside said 
pressure filter 4 is discharged to said air emission control means 14 via 
said waste drain 9L by compressed gas 12 (FIG. 10), and can be collected 
as a wastewater 9 (FIG. 11). Subsequently compressed gas 12 desorbs 
volatile organic compounds (VOCs) and radioactive radon from the VOCs and 
radon impregnated spent adsorbent (GAC, PA etc.) inside said pressure 
filter 4, and flows to said air emission control means 14, where a valve 
41 is open, a valve 42 is closed, and the emitted gas 9G containing VOCs 
and radon passes through said prescreens 45, 46, and 47, said gas outlet 
21, said valve 41, and said demister pad 22 for reduction of humidity, and 
through said adsorber 25 for reduction of VOCs and radon. The inlet gas 
sampling port 24 and the outlet gas sampling port 26 are for gas sampling, 
in turn, for determining the gas purification efficiency of said adsorber 
25. If the purified gas effluent 12A from said adsorber 25 meets the air 
quality standards, the purified gas effluent 12A is discharged to ambient 
air. 
Alternatively, said valve 41 and said valve 42 shown in FIG. 12 are closed 
and open, respectively, and the emitted gas 9G passes through said 
prescreens 45, 46, and 47, said gas outlet 21, said gas mover 23 and said 
venturi dilution means 40 for the purpose of dilution, so the purified gas 
effluent 44 will meet the air quality standards. A set of said prescreens 
45, 46, and 47 placed before said gas mover 23 is optional. Said prescreen 
45 comprises coalescing filter modules. Said prescreens 46 and 47 comprise 
fiberglass filter, fibrous activated carbon filter, hydrophobic reticulate 
foam, hydrophilic reticulate foam, or combinations thereof. The air 
emission control means 14 of this invention is also effectively applied to 
other air pollution control applications, such as purification of 
contaminated air stream from a commercial kitchen. 
Still alternatively, said venturi dilution means 40 and said valve 42 can 
be installed at a valve 4E of said pressure filter 4 (FIGS. 1A, 1B, 1C, 
1D, 1G, and 1l, for example) for a simplified desorption operation, so the 
air emission control means 14 may be idled. 
Still alternatively, said venturi dilution means 40 may be installed after 
said adsorber 25 for dilution of said purified gas effluent 12A shown in 
FIG. 11. 
In the case of the present invention, many conventional flow control valves 
for operation of said pressure filter 4 and said process tank 11 are 
eliminated and replaced by one central flow control means 3, while at the 
same time, various modes of filtration operation are easily controlled by 
dialing. Various liquid filtration applications are achieved by proper 
selection of reactive/regenerative filter media and regeneration 
chemicals. 
The simplification of the improved liquid filtration operation is 
accomplished by taking advantage of multiple on-off ports (not shown) 
inside of said central flow control means 3. By dialing a selected mode of 
operation which is marked on said central flow control means 3, only the 
applicable ports will be open, and the remaining non-applicable ports will 
be blocked simultaneously, thus directing the liquid to a proper treatment 
unit or pipe for treatment, processing or discharge. 
More than one said central flow control means 3 can be adapted if multiple 
modules of said apparatus together with pretreatment means 5 and 7 or 
post-treatment means 6 are required. 
The improvement of liquid treatment efficiency is accomplished by taking 
advantage of multiple reactive granular filter media 4F inside of said 
pressure filter 4. By choosing one or more feasible filter media and 
feasible filter aids, only the target contaminants are to be efficiently 
and selectively removed from said influent liquid Q1. Thus, the liquid 
treatment goal can be achieved at an affordable cost. 
The present invention provided by the inventors is designed to maximize the 
treatment efficiency while to minimize the operation effort, so the small 
municipalities, institutions, single families, or even individuals adopt 
said apparatus for water purification, effluent treatment, or special 
liquid purification. 
In most applications of the apparatus, the influent liquid Q1 is pumped to 
the apparatus at a velocity sufficient to ensure that liquid entering the 
apparatus system will flow through the center flow control means 3 and 
other treatment units or pipes as described. Thus, it is intended that the 
apparatus will ordinarily take advantage of the relatively high energy 
level imported to the liquid by pumping equipment from a pump 2. 
Also, it should be noted that the process tank 11 is essential only if the 
filter media regeneration (including filter precoat) or chemical 
flocculation is intended. In the event that filter media regeneration or 
chemical flocculation is not intended, the process tank 11 is idled. 
For a simplified liquid filtration operation in a residential building, the 
filter septum (filter element) 4S as well as the reactive filter media 4F 
in said pressure filter 4 can be of disposal type for the ease of 
operation and management. Normally, the filter septum 4S of this invention 
is porous plastic medium, porous stainless steel medium, or porous ceramic 
medium. The disposal type of the filter septum used in the present 
invention is of porous fiberglass medium, porous paper medium, porous 
carbon medium, or combinations thereof. The filter septum 4S can also be 
operated alone for filtration without any reactive or non-reactive 
granular filter media 4F. 
For continuous filtration service, multiple pressure filters 4 may be 
adopted in the present invention. When one of the pressure filters is to 
be operated at an operational mode other than the filtration mode, the 
remaining pressure filter(s) can be operated in filtration mode for 
continuous service. 
The apparatus of this invention is operated either manually using said 
central flow control means 3 or automatically using said same central flow 
control means 3. 
Alternatively said central flow control means 3 is replaced by a group of 
solenoid valves or automatic control valves which receive the programmed 
electronic/electrical signals and are open or closed in accordance with 
the operator's instruction as follows: 
Filtration Mode (FIG. 2) 
Valve 4P-5P and valve 6P-7P are open. All other valves are closed. 
Backwash Mode (FIG. 3) 
Valve 4P-6P and valve 5P-9P are open. All other valves of said group are 
closed. 
Bypass Mode (FIG. 4) 
Valve 4P-7P is open. All other valves of said group are closed. 
Flushing Mode (FIG. 5) 
Valve 4P-9P is open. All other valves of said group are closed. 
Preparation Mode (FIG. 6) 
Valve 4P-8P is open. All other valves of said group are closed. 
Recirculation Mode (FIG. 7) 
Valve 4P-5P and valve 6P-8P are open. All other valves of said group are 
closed. 
Precoat Mode (FIG. 8) 
Valve 4P-5P and valve 6P-8P are open. All other valves of said group are 
closed. 
Rinse Mode (FIG. 9) 
Valve 4P-5P and valve 6P-9P are open. All other valves of said group are 
closed. 
Desorption Mode (FIG. 10) 
Valve 6P-9P is open. All other valves of said group are closed. 
Finally, it should be noted that the process and apparatus provided by the 
present invention are used for removal of not only suspended particles, 
but also living microorganisms and soluble iron, manganese, heavy metals, 
hardness, volatile organic compounds, radioactive radon, and colloidal 
solids from contaminated river water, lake water, groundwater, domestic 
sewage, industrial process liquid, storm run-off and swimming pool water. 
For various specific applications, certain means of this invention will be 
emphasized, and the remaining means of this invention may be 
de-emphasized, idled, or disconnected for cost savings. 
For instance, for treatment of a highly contaminated water containing high 
concentrations of living, non-living, and radioactive contaminants, the 
apparatus of this invention comprising an ultraviolet pretreatment means, 
pump means, a chemical feed system, a process tank, a central flow control 
means, a pressure filter means, an ultraviolet post-treatment means, an 
air emission control means, and a piping system will be the most ideal 
filtration apparatus. 
When treating a groundwater contaminated by pathogenic bacteria, soluble 
metals and low concentrations of radioactive radon gas, all water treating 
means identified in the above paragraph will still be needed; however, the 
process tank can be simply a tank (without mixing, flocculating and 
solid-water separating means), and the air emission control means can 
comprise simply a tank, a gas mover and a venturi gas dilution means 
(without prescreens and/or an adsorber). 
If a heavily contaminated water contains no radioactive radon gas and 
volatile organic compounds, entire air emission control means of this 
invention can be idled or disconnected for cost saving although all other 
water treating means are still required. 
In case the apparatus and the process of this invention are to be applied 
to further purification of tap water in a single family home, many water 
treating means, such as said chemical feed system, control means, process 
tank, and pump means are already provided by a municipal water treatment 
plant, thus are not needed again. A standby pump, however, is installed as 
a part of the present invention's apparatus in case the water pressure in 
said influent liquid pipe occasionally is not sufficiently high to move 
said liquid throughout entire apparatus. The remaining water treating 
means (such as said piping system, said ultraviolet pretreatment and/or 
post-treatment means, and at least one pressure filter means) are 
essential for household water treatment applications. The membrane filter 
media can also be adopted as one of filter media to be used in said 
pressure filter means. 
The present invention is also very suitable for purifying process water in 
small commercial and industrial operations, such as automobile washing and 
glass cutting. Under such condition, special emphasis is placed on 
application of said chemical feed system, complete process tank 
(comprising means for chemical mixing, water flocculation, solid-water 
separation, and waste sludge discharge), said pump means, at least one 
pressure filter means, said ultraviolet post-treatment means, and the 
piping system. Besides, the filter media or filter cartridges inside said 
pressure filter means are either disposal type, requiring no backwash and 
regeneration, or permanent type, requiring off-site regeneration. As 
discussed previously, said process tank is to be operated as a sequencing 
batch sedimentation reactor, or a sequencing batch flotation reactor, or a 
sequencing batch exchanger reactor (U.S. Pat. application Ser. No. 
07/871041; filed Apr. 20, 1992 by Wang et al), or as a conventional 
flocculation-sedimentation reactor. The present invention described here 
for small commercial and industrial operations treats the contaminated 
process water for reuse, and produces no wastewater, except a small 
quantity of solid waste, such as the disposal type of filter cartridge or 
filter media. 
When treating contaminated water from large commercial and industrial 
installations, a complete process and apparatus of this invention will be 
required. The filter media will be backwashed and regenerated 
periodically. The wastewater and waste sludges produced from the present 
invention are to be discharged into a municipal sewer system for disposal.