Asbestos-containing materials removal assembly

An ACM removal assembly is disclosed, including: a nozzle for directing a pressurized fluid against ACM for dislodging the ACM; a fluid supply reservoir connected to the nozzle; a housing which supports the nozzle and capturingly receives spent fluid and dislodged ACM; and a material handing and separating system which includes coarse separating apparatus for coarsely separating the spent fluid from the dislodged ACM and fluid return conduit for returning coarsely separated fluid to the fluid supply reservoir. Also disclosed is a method for removing ACM from a building structure, including: sealingly circumscribing a small-area building region having exposed ACM with an ACM containment apparatus; removing ACM from the circumscribed building region with a fluid spray blast; combiningly capturing dislodged ACM and spent fluid from the spray blast in the containment apparatus; coarsely separating a portion of the ACM from the combined ACM and spent fluid; and reusing the coarsely separated fluid to remove ACM from the building.

BACKGROUND OF THE INVENTION 
The present invention relates to a system for removing asbestos-containing 
materials (ACM) from buildings. 
Since before the second World War through the early 1970's, as much as 300 
million tons of asbestos mineral had been used in building construction in 
the United States. By the early 1970's, medical evidence began to 
establish that asbestos exposure can cause severe and irreversible lung 
damage and various forms of cancer. By the early 1980's, public concern 
over the hazards associated with asbestos became manifest in legislation 
which (1) limited the use of asbestos in new construction; (2) specified 
procedures for asbestos removal in buildings; (3) required removal of 
asbestos-containing materials prior to building remodeling or demolition; 
(4) required management of asbestos in schools. 
The U.S. Environmental Protection Agency has estimated that about 45,000 
schools and 73,000 public and commercial buildings contain some form of 
asbestos-containing materials (ACM). These ACMs are typically (1) 
surfacing materials sprayed or troweled onto ceilings and walls; (2) 
thermal insulation on pipes, ducts, boilers and tanks; (3) miscellaneous 
materials such as ceiling and floor tile and wallboards. 
ACM removal is currently a heavily labor-intensive industry. Typically, 
surface ACM is removed by laborers using paint scrapers. The ACM is 
initially hand-wetted using sponges, low pressure water spray or the like, 
in order to reduce the amount of asbestos dust created during scraping. 
Thereafter, the ACM is scraped from its location in the building and 
allowed to fall to the building floor. Next, the dislodged ACM is shoveled 
up manually and placed in plastic bags. After the initial scraping of 
building surfaces with paint scrapers and the like, a final cleanup 
process is initiated to remove ACM from joints, crevices, beams, and other 
hard-to-reach areas in which large paint scrapers and the like are 
unsuitable. This cleanup process sometimes includes using pressurized 
water to blast the remaining ACM from its location on the building 
structure. Thereafter, all ACM, water, and other debris on the floor of 
the building is removed, typically by wet/dry vacuum units such as the 
type used in most shop and maintenance areas. As a final step, all 
surfaces of the building and enclosure are wiped down to remove any 
remaining ACM dust, etc. 
Although regulations for asbestos removal vary from state to state, 
typically the area from which ACM is to be abated is required to be sealed 
off from the surrounding environment to prevent discharge of airborne 
asbestos fibers into the surrounding environment. During any period in 
which ACM removal is taking place, the sealed-off area within the building 
enclosure is required to remain at a negative air pressure with respect to 
the surrounding environment. The negative air pressure is typically 
provided by a "hepafiltered" vacuum source. "Hepafilter" refers to a 
filter which removes substantially all airborne particles having a 
particle diameter of greater than 0.3 microns. During asbestos removal, 
the air within the sealed enclosure is sampled on a regular basis to 
determine the density of airborne particles within predetermined ranges. 
Workers within the enclosure are required to wear approved protection gear 
having a hierarchy based upon the airborne particles within the building 
enclosure. In order to reduce costs associated with the more expensive 
protection gear, most contractors attempt to reduce airborne particle 
concentrations within the enclosed ACM removal area to a minimum, 
typically by providing a replenishing air flow which replaces the air 
within the enclosure on the order of four times per hour. 
In order to prevent asbestos particles contained on the workers clothing 
and body from entering the atmosphere outside of the enclosed area, a 
triple air lock is typically provided at the entrance to the enclosed 
area. In the first area of the triple air lock positioned adjacent to the 
enclosed area, workers remove their protective gear and clothing, 
generally depositing it in sealed receptacles which are later removed from 
the area and cleaned or destroyed. After disrobing, a worker enters an 
intermediate area of the triple air lock which contains a shower. Each 
worker showers in this area and then progresses to the third area of the 
triple air lock in which clean clothes, etc., are provided. The water from 
the intermediate air lock shower is filtered to a particle size 
permissible for discharge into the surrounding sewer system, or ground 
water environment, typically 5 microns. In some cases, water which has 
been vacuumed from the floor of the enclosed ACM removal area by 
wet-vacuum in the final stages of cleanup is dumped into the worker's 
shower for filtering by the shower filter system. However, in most cases, 
the wet-vacuum container contains enough large ACM particles to prevent 
use of the shower as a filtering system, in which case all of the water 
and particles contained in the wet-vacuum are transferred to a barrel or 
other sealed receptacle for removal to an approved disposal site or for 
subsequent filtering. Due to the labor, dump fees, and inconvenience 
associated with removing large quantities of contaminated water to an 
asbestos disposal site, the use of water in ACM removal is minimized. 
Generally, blast spray water, when used at all, is applied at relatively 
high pressures, e.g. 5,000 psig or more, to decrease the total volume of 
water needed in any blast spray removal operations. The use of large 
amounts of water also damages underlying building structure such as floors 
and ceilings and has thus also been minimized to prevent unnecessary 
damage to the building. 
OBJECTS OF THE INVENTION 
It is an object of the present invention to provide an ACM removal system 
which eliminates much of the hand labor associated with ACM removal. 
It is another object of the present invention to provide an ACM removal 
system which is more cost-efficient than current ACM removal methods. 
It is another object of the present invention to provide an ACM removal 
system which is relatively faster than current ACM removal methods. 
It is another object of the present invention to provide an ACM removal 
system which enables the use of relatively lower blast water pressure than 
that currently used in the industry. 
It is another object of the present invention to provide an ACM removal 
system which utilizes a relatively large volume of water flow for the 
removal and handling of ACM. 
It is another object of the present invention to provide an ACM removal 
system which reduces the density of airborne particles created during ACM 
removal as compared to current methods. 
It is another object of the present invention to provide an ACM removal 
system which eliminates the need for a negative pressure environment in 
the building enclosure in which ACM removal is taking place. 
It is another object of the present invention to provide an ACM removal 
system which provides a continuous process in which ACM is removed from a 
building in slurry form and in which blast water is coarsely removed from 
the ACM slurry and reused for further ACM removal and in which the blast 
water is more finely removed from the ACM slurry and discharged into the 
local municipal sewer at the completion of ACM removal whereby the 
necessity of disposing of large quantities of waste water at an approved 
ACM dump site is eliminated. 
It is another object of the present invention to provide an ACM removal 
system which utilizes a mobile housing unit which encloses a blast spray 
and which serves as an initial collection area for ACM and waste blast 
spray. 
It is another object of the present invention to provide an ACM removal 
system which utilizes a mobile housing unit which provides a localized 
enclosure in an specific region of a building in which ACM removal is 
taking place to prevent propagation of water overspray and ACM particles 
into the surrounding environment. 
SUMMARY OF THE INVENTION 
The present invention may include an ACM removal assembly comprising: 
nozzle means for directing a pressurized fluid against ACM which is 
supported on a building structure for dislodging the ACM; pressurized 
fluid supply means operably connected to said nozzle means for supplying 
fluid under pressure thereto; and housing means for supporting said nozzle 
means therein and for capturingly receiving spent fluid and dislodged ACM. 
The present invention may also include a method for removing ACM from a 
building structure comprising: sealingly circumscribing a first building 
region having exposed ACM with an ACM containment apparatus; removing ACM 
from the circumscribed building region with a fluid spray blast; 
combiningly capturing dislodged ACM and spent fluid from the spray blast 
in the containment apparatus; separating a portion of the ACM from the 
combined ACM and spent fluid; and reusing the coarsely separated fluid to 
remove ACM from a second building region. 
The present invention may also include an ACM removal assembly comprising: 
nozzle means for directing a pressurized fluid against ACM which is 
supported on a building structure for dislodging the ACM; pressurized 
fluid supply means operably connected to said nozzle means for supplying 
fluid under pressure thereto; housing means for supporting said nozzle 
means therein and for capturingly receiving spent fluid and dislodged ACM; 
and material handing and separating means operably connected to said 
housing means for receiving combined spent fluid and dislodged ACM from 
said housing means for separating said spent fluid from said dislodged 
ACM; said material handling and separating means comprising coarse 
separating means for coarsely separating said spent fluid from said 
dislodged ACM and fluid return means for returning coarsely separated 
fluid to said pressurized fluid supply means; said material handling and 
separating means comprising fine separating means for receiving coarsely 
separated fluid from said coarse separating means and for finely 
separating ACM therefrom.

DETAILED DESCRIPTION OF THE INVENTION 
FIG. 1 schematically illustrates an ACM (asbestos-containing material) 
removal assembly 10 which is adapted to remove ACM 12 from supporting 
building structure 14. The ACM removal assembly in general comprises 
nozzle means 16, 18, 20, FIGS. 3 and 4, for directing a spray of 
pressurized fluid 15 such as water against ACM 12 for dislodging it. The 
nozzle means 16, 18, 20 are operably connected to pressurized fluid supply 
means 25, FIG. 1, which supplies fluid under pressure thereto. The nozzle 
means 16, 18, 20 are supported within housing means 30 which is adapted 
for capturingly receiving spent fluid 21 and dislodged ACM 13, FIG. 4. 
Material handling and separating means 84, 124, 130, 146, 158, 162, etc., 
are operably connected to the housing means 30 for receiving combined 
spent fluid and dislodged ACM from the housing means 30 for separating the 
spent fluid 21 from the dislodged ACM 13. The material handling and 
separating means includes coarse separating means 130, 146, etc., for 
coarsely separating the spent fluid from the dislodged ACM, and fluid 
return means 150, 152, etc., for returning coarsely separated fluid to the 
pressurized fluid supply means 25. The material handling and separating 
means also comprises fine separating means 158, 162, etc., which is 
typically used only at the end of an ACM removal job. The fine separating 
means is adapted for receiving coarsely separated fluid from the coarse 
separating means 130, 146, etc., for finely separating ACM from the 
coarsely separated fluid to provide a finely filtered fluid which is 
sufficiently filtered to be discharged into the local sewage system or 
local earth/water environment. A negative air pressure may be provided 
within the housing means 30 and sealing devices, e.g. 46, 52, 62, may be 
provided in associated with the housing to prevent fluid overspray and 
contamination of the air within the building enclosure with ACM airborne 
particles. The housing assembly 30 may be mounted on a wheeled carriage 94 
or the like to facilitate movement of the housing assembly 30 and 
associated spray nozzle 16, 18, 20 to selected areas within the building 
from which ACM is to be removed. Having thus described the ACM removal 
assembly 10 in general, various specific features of the assembly will now 
be described in further detail. 
As illustrated in FIGS. 3 and 4, a plurality of spray nozzles (e.g. three 
spray nozzles, 16, 18, 20, which may be conventional washjet cleaning 
nozzles such as that sold under model designation 6504 1/4 MEG by Spraying 
Systems Company of North Avenue, Wheaton, Ill., 60188) are mounted on a 
spray nozzle conduit 22 which may be, e.g., a 3/4-inch circular pipe. 
Spray nozzle conduit 22 is capped at one end thereof and is connected at 
the other end thereof to a water line 24 which is connected to a water 
supply reservoir 25. Reservoir 25 may be, e.g., a 50-gallon supply 
reservoir. A water pump 26 is operably mounted in water line 24. The pump 
power rating, e.g. 15 h.p., is matched to the water requirements of the 
spray nozzle. In a preferred embodiment, the nozzles are adapted to apply 
water at a pressure up to 5000 psi and preferably are operated in a range 
from 1000-2000 psi. The flow rate requirements of the nozzles are 
typically up to 10 gallons per minute each and are preferably operated in 
a range of 2-5 gallons per minute each. As illustrated in FIG. 1, a 
signal-actuated control valve 28 may be provided in the water line 24 for 
shutting off the supply of water from the water supply reservoir 25 in 
response to a control signal, as further described below. A branch line 29 
connected to line 24 is adapted for use in removing water from reservoir 
25 at the completion of an ACM removal job is also described below. Flow 
of water into line 29 may be controlled by operation of conventional 
control values 31 and 33 located in lines 29 and 24, respectively. 
Housing 30, as best illustrated by FIGS. 2-4, comprises an enlarged upper 
end portion 32 terminating in a square, upper opening 34, which may have 
an open area of, e.g., 1 square foot. The enlarged upper end portion may 
have an inverted, irregular pyramid-type shape. The spray nozzle conduit 
22 is supported on two sidewalls of the enlarged upper end portion 32 
through appropriately-sized bores therein. The spray nozzle conduit 22 may 
be positioned, e.g., 2-4 inches below the upper edge of opening 34. The 
centerline of each spray blast from nozzle 16, 18, 20 may be adjustable 
and may be inclined, e.g., 45.degree. with respect to the upper periphery 
of opening 34. The housing 30 also comprises a restricted lower end 
portion 36 which is integrally formed with the upper end portion 32 and 
which terminates in a lower opening 38 which may be circular in shape and 
which may have an opening area of, e.g., 0.02 square feet. In one 
embodiment of the invention, dislodged ACM and spent fluid 13 is 
capturingly received in the housing upper end portion 32 and is discharged 
by gravity through the restricted lower end portion 36. In another 
embodiment of the invention, as illustrated in FIG. 4, conveying means 
such as an auger 40 are provided in the lower end portion 36 to facilitate 
removal of ACM and spent fluid from the housing 30. The auger 40 may be 
conventionally mounted within the housing and may be powered by a 
conventional auger motor 41, FIG. 2. 
As illustrated in FIGS. 3 and 4, a vacuum monitoring gauge 42 is provided 
in the housing for monitoring the pressure therein. The vacuum monitoring 
gauge 42 may be operably connected with water line shutoff valve 28 for 
terminating the supply of water to spray nozzle 22 in the event that the 
pressure within the housing 30 rises above a predetermined negative air 
pressure value, e.g. above -0.5 psig. 
A conventional blowoff valve 44 provided with a hepafilter, which may be 
set at, e.g., 1.0 psig, is provided as a safety device for relieving 
positive pressure within housing 30 in the event of system malfunction. 
A bristle brush-type seal 46 is provided about the periphery of opening 34 
by a plurality of closely-spaced brush bristles which may each have a 
length of, e.g., 1.0 inches. The bristle seal is adapted to allow inflow 
of air therethrough while restricting nozzle overspray and restricting 
discharge of ACM particles into the surrounding atmosphere. 
A pressure ring 52 which circumscribes the upper housing opening 34 may be 
fixedly mounted on the housing 30, as illustrated in FIGS. 3 and 4. 
Pressure ring 52 may have an annular opening 54 at an upper end. 
Pressurized air is sent to pressure ring 52 through at least one inlet 
opening 55 which may be provided in a lower portion thereof. The inlet 
opening is placed in fluid communication with a pressurized air source 
such as air compressor 58 through a pressure hose 56. Compressor 58 may be 
located inside or outside of the building enclosure 11. A conventional 
shutoff valve 60 may be provided in the pressure hose 56 for terminating 
air flow from the air source 58. The pressurized air source may provided 
air at a pressure of, e.g., 2.0 psig to pressure ring 52 at a flow rate 
of, e.g., 50 cfm. 
As best illustrated by FIGS. 2-4, a vacuum ring 62 may be mounted on the 
pressure ring 52 in circumscribing relationship therewith. The vacuum ring 
62 comprises an annular opening 64 in an upper end portion thereof. Vacuum 
ring 62 is placed under negative pressure, e.g. -0.9 psig, by a vacuum 
source 68 which communicates with the vacuum ring 62 through vacuum hose 
66 and vacuum ring inlet opening 65. A vacuum shutoff valve 72 may be 
provided in association with the vacuum source 68 to terminate air flow 
thereto. The vacuum source 68 may be a conventional vacuum pump provided 
with hepafilters for filtering the air discharged therefrom down to a 
particle size of less than 0.3 microns in diameter. The airflow rate 
through vacuum ring 62 may be, e.g., 50 cfm. Alternatively, vacuum ring 62 
may be placed under vacuum by the vacuum pump associated with the wet/dry 
vacuum assembly 84 described below. 
Second and third annular bristle seals 53, 63 similar in construction and 
use to annular bristle seal 46 may be provided in association with annular 
pressure ring 52 and annular vacuum ring 62, respectively, as shown 
partially in FIG. 3. As best illustrated by FIG. 2, the lower opening 38 
of housing 30 communicates with a wet/dry hepavacuum assembly 84 through a 
flexible conduit 82 which is connected to housing 30 and to the vacuum 
pump 86 by appropriate adapters. In one embodiment of the invention, the 
flexible conduit comprises a diameter of approximately 2.0 inches an the 
wet/dry vacuum assembly comprises a tank 88 having a capacity of 30 
gallons. The wet/dry vacuum assembly may have a vacuum pump 86 capable of 
providing a negative pressure of approximately -3.6 psig within housing 
30. The wet/dry vacuum assembly 84 may be a conventional wet/dry vacuum 
assembly such as are used at most construction sites and maintenance 
shops, e.g. that manufactured under the product designation 2HP Wet/Dry 
Hepavac by Control Resource Systems, Inc., 670 Mariner Drive, Michigan 
City, Ind., 46360. The wet/dry vacuum assembly is adapted to collect an 
unprocessed slurry of water and ACM in tank 88 thereof. A second flexible 
conduit 92 is connected to tank 88 at an opening in the bottom thereof and 
is connected at an opposite end to material handling and separating means 
as described in further detail below. 
In one preferred embodiment of the invention, the wet/dry vacuum assembly 
84 is mounted on a wheeled carriage assembly 94 and the housing 30 is 
mounted on a pivot assembly 96 which is, in turn, supported on the wet/dry 
vacuum assembly and wheeled carriage assembly. The pivot assembly 96 may 
comprise a first pivot arm 98 mounted on top of tank 88 and having a 
counterweight 102 supported at one end thereof and a second pivot assembly 
104 mounted at the other end thereof. A second pivot arm 106 is mounted on 
the second pivot assembly at one end thereof and a third pivot arm 
assembly 108 is mounted at the other end of the second pivot arm 106. A 
biasing spring 110 is mounted in circumscribing relationship about the 
third pivot arm assembly 108 between the second pivot arm 106 and a collar 
assembly 112. The collar assembly 112, in turn, supports the housing 30 
thereon. Biasing spring 110 is adapted to urge the collar assembly 112 and 
housing 30 upwardly so as to urge bristle seal 46 against a building 
region from which ACM is to be removed. 
As illustrated by FIG. 1, flexible conduit 92 places wet/dry vacuum tank 88 
in fluid communication with a slurry holding tank 124. A pump 122, which 
may be located inside or outside of enclosure 11, having a capacity at 
least as great, and preferably about twice as great, as the capacity of 
blast water supply pump 26 is adapted to pump slurry from tank 88 to 
slurry holding tank 124. Slurry holding tank 124 may have a capacity of 
200 gallons. 
A pump 126 operably mounted in a slurry line 128 is adapted to pump slurry 
from slurry holding tank 124 to a first separator device 130 such as a 
conventional dewatering separator, which may be a Lakos AXL series 
AXL-0100-B dewatering separator manufactured by Lakos Separators U.S.A (a 
division of Claude Laval Corp.), 1911 North Helm Avenue, P.O. Box 6119, 
Fresno, Calif., 93703-0119. Such a separator deVice 130 typically removes 
ACM particles having a diameter of greater than 74 microns. The separator 
device 130 discharges separated ACM particles 134 to an ACM collection 
tank 136 and discharges initially separated slurry through slurry line 
144. The discharged ACM particles 134 may be further dewatered to remove 
fluid bulk therefrom as by a dewatering screen 132 which may be a 
conventional dewatering screen such as that sold under model designation 
Hydroscreen model HS-18 by Hycor Corp., 29850 North Hwy. 41, Lake Bluff, 
Ill., 60044. Fluid from the dewatering screen may be discharged through 
fluid line 138 back into slurry holding tank 124. As further illustrated 
by FIG. 1, slurry line 128 may be connected to a feedback line 140 
controlled by a control valve 142. A control valve 143 may also be 
proVided in line 128 at the inlet to separator 130. Valves 142 and 143 may 
be selectively operated to control the flow rate of slurry to separator 
device 130. 
The initially separated slurry discharged from separator 130 may be further 
refined as by a coarse filter device 146. Coarse filter device 146 may 
comprise a device which filters the slurry down to a maximum particle size 
which is acceptable for use in blast spray water, e.g. a size of 
approximately 300 microns in diameter and may comprise an automatic 
backflush-type strainer such as that sold under the product designation 
model type WJR filter 15 manufactured by R. P. Adams Co., 225 East Park 
Drive, Buffalo, N.Y., 14240-0963. Such a filter device includes a 
backflush assembly 147 which enables backflush cleaning of filter 146 and 
discharge of the backflush material through backflush line 148 into slurry 
holding tank 124. Coarse filter device 146 discharges coarsely refined 
slurry through lines 150 and 152 to water supply reservoir 125 in one 
operating state of the ACM removal assembly 10 in which a control valve 
156 in a connected branch line 154 is closed and a control valve 155 in 
line 152 is open. In a second operating state of the ACM removal assembly, 
control valve 15 in branch line 154 is opened and control valve 155 in 
branch line 152 is closed. In this second operating state, the coarsely 
separated slurry is directed through first fine filter unit 158, line 160, 
and second fine filter unit 162 to provide a finely separated slurry which 
is discharged through line 164 into local municipal sewer drain 166 or the 
local earth/water environment. Fine filter units 158 and 162 are adapted 
to filter out particles down to a size which are suitable for discharge 
into the environment. Current regulations typically specify this particle 
size to be on the order of 5 microns. In one specific embodiment of the 
invention, filter 158 comprises a Stranrite UF-180 filter unit 
manufactured by Stranrite Company of 190 Wallace Street, New Haven, Conn., 
06513. Unit 158 is equipped with a 100-micron filter screen. Unit 162 may 
be identical to unit 158 except that it is equipped with a 5-micron filter 
screen. 
In one preferred embodiment of the invention, slurry pump 122, slurry 
holding tank 124, slurry pump 126, separator device 130, dewatering device 
132, asbestos holding tank 136, coarse filter device 146, fine filter 
units 158, 162, reservoir 25, spray water pump 26, air compressor 58, and 
vacuum pump 68 are all positioned externally of a building enclosure 11 
from which asbestos-containing material is to be removed. Each of these 
components may be mounted in a unitary transport device 170 such as, for 
example, a truck trailer or the like, which may be conveniently pulled 
alongside a building from which ACM is to be removed. 
In operation, carriage 94 which supports housing assembly 30 and wet/dry 
vacuum unit 84 is moved to a selected building region, e.g. 180, from 
which exposed ACM is to be removed. An operator appropriately adjusts the 
position and elevation of pivot assemblies 96, 104, 110, etc., so as to 
urge the upper housing opening into sealing relationship with the selected 
building region. This is typically accomplished by compressing the 
bristles in bristle seal ring 46 slightly, e.g. 20%, against the exposed 
ACM 12. Next, a fluid spray blast from nozzles 16, 18, 20 is directed 
against the circumscribed ACM as the housing assembly 30 is slowly moved 
across the ceiling, preferably in a straight-line path in a series of 
sweeps in much the same manner, for example, that one would mow a lawn. 
The spray blast is provided through actuation of pump 26 such as by 
actuation of an electric motor associated therewith (not shown) or 
appropriate valves (not shown) associated therewith. As ACM is dislodged 
by the spray blast, it falls into housing 30 which is positioned 
immediately therebelow and is channeled downwardly therethrough by gravity 
and/or associated conveying device 40. Spent fluid from nozzles 16, 18, 20 
is also captured in housing 30 and flows downwardly therethrough. 
Before or simultaneously with the discharge of spray through nozzles 16, 
18, 20, wet/dry vacuum assembly 84 is actuated to draw dislodged ACM and 
spent fluid from nozzles 16, 18, 20 into tank 88. An ACM slurry 90 is thus 
collected in tank 88 which is preferably removed therefrom in periodic 
intervals through use of pump 122. Pump 122 may be actuated manually or 
may be actuated automatically as by float valves or the like (not shown) 
provided in tank 88. Slurry 90 is pumped to holding tank 124 which is 
preferably located outside of building enclosure 11. Pump motor 126, which 
may also be operated either manually or through appropriate float valves 
or the like within tank 124, pumps slurry from tank 124 to separator 
device 130. Separator device 130 initially separates relatively large ACM 
particles 134 from a slurry which is discharged therefrom through line 
144. Particles 134 are further separated from fluid clinging thereto by a 
dewatering unit 132 which returns the fluid thus separated from the 
particles to tank 124. The inflow of slurry to separator 130 may be 
controlled through control of valves 142 and 143 to enable continuous 
operation of pump 126 rather than intermittant operation thereof. 
Operation of control valves 142, 143 may be performed manually or through 
the use of float gauges (not shown) associated with tank 124, etc. 
Asbestos particles 134 are collected in container 136 which may be 
periodically sealed and removed from below units 134 and 132 or discharge 
to another sealable container. The initially refined slurry discharged 
from separator device 130 is filtered in coarse filter device 146 which 
discharges a coarsely filtered slurry into line 150. Line 150 communicates 
with branch lines 152 and 154. During normal operation of the spray blast 
for removal of ACM, control valve 155 in line 152 is open and control 
valve 156 in line 154 is closed. Thus, the coarsely separated slurry from 
line 150 passes through line 152 and returns to fluid reservoir 25 and is 
thus reused by the system to removingly blast ACM 12 from supporting 
building structure 14, for example, at a second building location 182. At 
the completion of the ACM spray blasting removal operation, the flow of 
water to nozzles 16, 18, 20 is terminated by closing control valve 33, and 
control valve 31 is simultaneously opened to enable pumping of water from 
reservoir 25 directly into slurry holding tank 124. After fluid flow to 
nozzles 16, 18, 20 has been terminated, motor 122 continues to operate 
until all of the slurry 90 in wet/dry vacuum tank 88 has been pumped to 
slurry holding tank 124. Approximately simultaneously with the closure of 
valve 33, valve 155 is closed and valve 156 is opened, thus allowing all 
of the coarsely separated slurry in line 150 to be directed through filter 
units 158, 162. The finely separated slurry discharged from fine filter 
162 is typically discharged into a municipal sewer system. The collected 
ACM particles in collection tank 136 are appropriately sealingly enclosed, 
for example, in plastic bags, sealed containers or the like, and removed 
to appropriate ACM disposal sites. 
During operation of spray nozzles 16, 18, 22, air provided under pressure 
to pressure ring 52 is discharged through outlet 54 to provide an 
encompassing inward air flow through bristle ring 46 which acts to prevent 
discharge of overspray or ACM particles through bristle seal 46. At the 
same time, a vacuum is also applied to vacuum ring 62 which provides a 
flow of air from pressure ring opening 54 to vacuum ring opening 64 which 
tends to capture any overspray or particles which may have initially 
escaped through bristle seal 46. Thus, the inward air flow through bristle 
seal 46 which is provided by the vacuum developed by wet/dry vacuum 
assembly 84 is further enhanced by pressurized air flow from pressure ring 
52, and any escaping particles from the bristle seal which are not 
redirected through the bristle seal back into housing 30 are carried by 
the air flow from pressure ring 52 into outer vacuum ring 62. Further 
pressure rings (not shown) and further vacuum rings (not shown) may also 
be provided in alternating concentric relationship with rings 52 and 62 to 
provide further annular air seals to further prevent overspray and 
particle discharge into the atmosphere surrounding housing 30. 
Although a housing having a horizontally disposed top opening with 
square-shaped opening configuration has been described for removal of ACM 
from a ceiling region of a building, it will be appreciated that housing 
openings having various other configurations may be provided for engaging 
different ACM-covered surfaces of a building. For example, an arcuate, 
vertically disposed housing opening (not shown) could be provided for 
removing ACM from cylindrical pipes, wedge-shaped housing openings (not 
shown) could be provided for removing ACM from corner regions of walls and 
ceilings, etc. It will also be appreciated that multiple housing units 
might be employed and associated with a single or multiple collection 
vacuum sources, and such housing units might be mounted on various 
different types of portable assemblies which may be hand-carried 
assemblies as well as carriage-type assemblies, etc. 
Thus, while an illustrative and presently preferred embodiment of the 
invention has been described in detail herein, it is to be understood that 
the inventive concepts may be otherwise variously embodied and employed 
and that the appended claims are intended to be construed to include such 
variations except insofar as limited by the prior art.