IMPROVEMENTS IN TREATING SEWAGE
Year: 1876

page_text: LETTERS PATENT to Fritz Hille, of Chiswick, in the County of Middlesex,
Engineer, for the Invention of "IMPROVEMENTS IN TREATING SEWAGE."
the 26th May 1876, and dated the 29th March 1876.
PROVISIONAL SPECIFICATION left by the said Fritz Hille at the Office of
the Commissioners of Patents on the 29th March 1876.
FRITZ HILLE, of Chiswick, in the County of Middlesex, Engineer.
MENTS IN TREATING SEWAGE."
" IMPROVE-
This Invention has for its object improvements in treating sewage.
The sewage of sea coast towns or other places may advantageously be treated by
chemical means before being discharged into the sea or rivers, so as to remove foecal
matters, excreta, or other refuse, and prevent the pollution of the otherwise pure
waters in rivers or sea.
For the purification of sewage to be generally carried out the process resorted to
must not only be simple but also cheap and practical for every day work. For
places near the sea I use the following materials for precipitation, and defecation,
and deodorization of sewage, namely:-Lime and tar, and sea water if possible
from the in-coming tide. These ingredients are mixed in the following manner :-
The lime is slacked with a sufficient quantity of sea water so as to produce the
greatest possible heat, when so heated and in the form of a paste the tar is added
to the slacked lime, and both are worked together until they are intimately mixed
and the mass is all through of the same color. When this composition has been
obtained the paste is dissolved or diluted with sea water, and the disinfecting milk
thus obtained may be used for the treatment of the sewage. By preference I
prepare this disinfecting milk in the following way, and in the following propor-
tions For every 100 lbs. of lime I take the necessary quantity or weight of pure
sea water, if possible from the incoming tide, for slacking the lime, and add 5 lbs. of
tar to the lime when hottest; when a paste as above described has been formed one
pound in weight of the paste may be dissolved in from 15 to 20 lbs. of pure sea
water. The disinfecting milk so obtained should be used for the purification and
deodorization of sewage in the proportion of from lb. to 1 lb. for every 100
gallons of sewage, or more or less, according to local circumstances. The effluent
water from sewage thus treated and allowed to subside, may be without offence or
nuisance discharged into the sea or into a river.
:-
[Price 4d.]

page_text: Great difficulty has always heretofore been experienced in the efficient disposal
of sewage deposits on account of its watery condition, and the foul smell emanating
from it particularly in hot weather. It becomes therefore, for efficient disposal of
the sewage deposit, an absolute necessity to produce a sludge which will dry quickly
solely by the influence of atmospheric air, and which at the same time is, as far as
odour is concerned, harmless and inoffensive. Further, it is necessary to create the
smallest possible quantity of sewage deposit. Now, the disinfecting compound
which I use is in so far peculiar that the sludge produced is perfectly harmless as
regards noxious or offensive gases, even if exposed to the hottest sun, and it dries
very rapidly without employing artificial heat. Besides this the sludge produced
by precipitating the sewage inatters may be used again for the samo purpose.
I make my arrangements for sludge disposal in this way-Tanks are required for
the precipitation and purification of sewage and land for filtering the effluent water
afterwards, or for irrigation purposes. Now, after treating the sewage one day
with the disinfecting compound, the deposit produced during that day I use the
next day for what I call the irrigation mixture, in distinction from the precipitation
mixture. This irrigation mixture is formed in this way I mix a pound weight
of the precipitation mixture to every 5 lbs. in weight of the deposit produced by
precipitation, and I dilute the mixture in the ordinary way with water, and apply
it as my irrigation mixture to sewage for disposal on land. By this means the
great objection to irrigation with raw sewage is overcome, as my irrigation mixture
prevents all smell arising from sewage, the cost for treating sewage is enormously
reduced, and the quantity of sewage deposit is reduced by these means to a mini-
mum, in fact by judicious arrangements of tanks and land no sewage deposit need
accrue on sewage works, carried out according to my plan, and the great difliculty
of disposing of sewage refuse is thus entirely overcome.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Fritz Hille in the Great Seal Patent Office on the 29th September
1876.
FRITZ HILLE, of Chiswick, in the County of Middlesex, Engineer. " IMPROVE-
MENTS IN TREATING SEWAGE."
This Invention has for its object improvements in treating sewage.
For the treatment of sewage according to my plan, no specially designed tanks
are necessary, as any deposit tank or reservoir may be used for the clarification.
deodorization, and purification of sewage according to this method. However in
arranging sewage works either inland or on or near the sea coast, it is desirable
that a reservoir should be provided of sufficient storage capacity to hold the
ordinary night and Sunday flow of sewage, so as to do away with night and Sunday
work, which arrangeinent from the beginning will allow of reducing the working
expenses. Before the sewage reaches this reservoir a screen ought to be provided
in a penstock or chamber, easily to be emptied and changed so as to prevent any
heavy substances contained in the sewage from reaching the works, and further at
the inlet into the reservoir ought to be an iron cage or grating, to be used for the
storage of the disinfecting compound in paste form (before it is diluted with water,
and formed into the disinfecting fluid), which the sewage when flowing into the
reservoir gradually dissolves and so purifies itself. This arrangement prevents any
smell arising from the reservoir.
With regard to the arrangements of tanks, filtering beds, and outlet chambers,
particularly where sewage reaches the outfall works by gravitation provisiou ought
to be made, by preference, by means of a distinct storm outlet or outlets, or other-
wise that storm or rain water in excess of the ordinary flow of sewage (where there
is no separate system of drainage for such waters) may be discharged direct from

page_text: the sowers or from the reservoir above named into river or sea, without passing
through the tanks and filters, there being no necessity for purifying ordinary rain or
storm water.
Before reaching and flowing into the deposit tanks the sewage and disinfecting
liquid are to be thoroughly mixed. The greater the amount of amalgamation and
mixing, between the sewage and disinfecting compound, the greater is the effect
produced as regards clarification, deodorization, and purification, and the sinuller
comparatively is the quantity of chemicals required for efficient treatment, and con-
sequently the smaller is the cost. This thorough mixing and amalgamation of
sewage and disinfecting agent may be effected by preference, by means of revolving
agitating wheels in a mixing chamber constructed for that purpose, or by letting
sewage and disinfecting liquid run together a sufficient distance in the sewer to
produce the same effect, or by pumping sewage mixed with the disinfectant direct
from a mixing well into the tanks, or by means of other mechanical contrivances,
for instance, by means of channels or culverts leading along or round the deposit
tanks, such conduits having bricks or wooden partitions inserted at certain distances
on their walls, so as to create an often broken current, by the mixed liquid winding
and forcing its way along these troughs, before entering the tanks, or by similar
contrivances.
A set of three deposit tanks will generally be found sufficient; more or less may
have to be provided according to the quantity of sewage to be treated. The width
of the tanks should not be more than one-third to one-fifth of their length, and tho
depth should not exceed from four to five feet, so as to facilitate casy cleaning out.
The bottom of the tanks ought to be slightly sloped, and to have an incline towards
the sludge outlet.
Having particularly in view the daily emptying and cleaning of the tanks, sluices,
or valves or syphons should be provided to facilitate the drawing off of the purified
water. Of the three tanks two may be used together, when the third tank has to
be cleaned out, and provision is to be made that each tank may be filled separately,
so that when filled the purified fluid may have time to rest and to settle, thereby
producing a higher degree of clarification, deodorization, and purification, or the
purified water may pass after filling one tank into another tank, and may be
discharged direct from the second tank into the river, or sea, or on to land or filtering
beds, thus using two tanks only simultaneously, or the purified water may pass after
filling two tanks into the third tank, so that all three tanks or more, according to tho
number may be used at the same time, having thus a continuous flow from one tank
into another; the sewage and disinfecting compound flowing into the first tank and
after clarification, deodorization, and purification, the purified water flows from the
third or from the last tank, by means of floating self acting outlets, which may be
filled with coke or other filtering material, or over an ordinary overflow or otherwise
on to the artificial filters or on to the land to be used for filtration or irrigation, or
the purified water is discharged direct into the river or sea.
The manipulation of daily cleaning out the deposit tanks and the daily removal
of the deposit enables me to use the precipitate resulting from the addition of the
precipitation mixture, as described underneath, to the sewage a second time for the
same purpose, and thereby,-
1. I effect a considerable saving of chemicals for the efficient, clarification,
deodorization, and purification of sewage.
2. The precipitate ultimately produced is much richer in fertilizing ingredients,
and constitutes a good manure, which quickly dries in the air.
3. Where land can be had for filtration or for irrigation my arrangements solve
the most difficult part of the sewage question, namely, the disposal of raw sewage
and the disposal of the sludge resulting from precipitation, as described later on.
I will now give a description of my chemical treatment of sewage, and of the
combination of chemicals used for the clarification, deodorization, and purification
of the same.
Dealing with places near the sea I use the following materials for the clarification,

page_text: deodorization, and purification of sewage, namely, lime and common gas tar, and
sea water from the incoming tide. These ingredients are mixed in the following
manner The lime is slaked with a sufficient quantity of sea water so as to
produce the greatest possible amount of heat. When that heat has been obtained,
and lime and sea water are in the form of a paste, the tar is added to the slaked
lime, and both are worked together until they are intimately mixed, and the pasto
is all through of the same greyish color.
I proceed in the following way -For every one hundred pounds of weight of
lime take the necessary quantity in weight of pure sea water, if possible, from
the incoming tide for slaking the lime, and add 5 lbs. in weight of tar, or
more or less, to the lime when hottest. When a paste as above described has been
formed one pound in weight of the paste may be dissolved in or diluted with from
10 to 15 or 20 pounds, or more or less, in weight of the pure sea water. The
paste of lime and tar and sea water should be used for the clarification, deodoriza-
tion, and purification of sewage in the proportion of from half a pound to one
pound, or more or less, for every 100 gallons of sewage, according to local circum-
stances. The effluent water from sewage thus treated in the way as before
described, and having sufficient time allowed to subside and to settle, may be, after
filtering, or without being filtered, according to locality, without causing any
offence or nuisance, discharge into the sea or into a river.
Where there is no available space for artificial downward or upward filtration
for filtration through land or for irrigation, there advantageously may be constructed
at the overflow from the deposit tanks an outlet chamber or outlet basin, and in
this chamber or basin may be added to the effluent for further purification a small
quantity of a solution of perchloride of iron, or carbonic acid gas may be forced
into the purified water. This carbonic acid gas produces extraordinary purification,
and any excess of lime in the effluent will be precipitated as carbonate of lime so
that alkaline reaction is avoided.
Finally a small vertical filter composed of burnt ballast, or of any of the
materials previously named, may be constructed, through which the effluent water
may pass into river or sea.
Where sea water is not obtainable, I use instead of sea water a combination of
salts of magnesium, by preference calcined chloride of magnesium, with or without
chloride of calcium, or the refuse liquor from salt works dried and calcined and
redissolved in water.
As already mentioned, great difliculty has always heretofore been experienced in
the easy, quick, and efficient disposal of the sewage deposit resulting from chemical
treatment and from precipitation, on account of its watery condition and the foul
smell emanating from it, particularly in hot weather. Now the disinfecting com-
pound which I use is in so far peculiar that the sludge produced is quite harmless as
regards the developement of noxious or offensive gases therefrom, if exposed even to
a hot sun, and it dries very rapidly, without employing artificial heat; besides this,
the sludge obtained from precipitation of the sewage matters may be used again for
the same purpose, with almost equal effect as when applied first.
I make my arrangements for disposal of the sewage deposit in this way-After
treating the sewage one day with the disinfecting compound, which I call the
precipitation mixture, I use the deposit produced during that day, or part of it, the
next day, for what I call the irrigation mixture in distinction from the precipitation
mixture. The irrigation mixture I make up in this way and proportion:-To one
pound in weight of the precipitation mixture are put 5 lbs. in weight, or more or
less of the deposit produced by precipitation, and when well mixed together I
dissolve or dilute every one pound of the whole mixture with about 5 lbs. or more
or less in weight of water, by preference sea water, if it can be had. This fluid I
apply as my irrigation mixture to sewage for disposal on land, whether for irrigation
or for filtering purposes.
It is desirable that the sewage and irrigation mixture should be thoroughly and
well mixed together, and when this has been effected in the mixing chambers or

page_text: otherwise, the sewage and irrigation mixture together may be sent direct on to the
land without passing the deposit tanks or filters, and thereby I effect a very
considerable saving in chemicals, in labor, and in cost; by this means the great
objection to irrigation with raw sewage is overcome, as my irrigation mixture
prevents any smell arising from sewage; the cost of treating sewage is enormously
reduced, the condition of the sewage deposit is rendered quite inoffensive, very
compact, and it can be easily handled and removed. The quantity of the sewage
deposit is by this arrangement reduced to a minimum; in fact, by judicious
management and arrangements of tanks and land no sewage deposit need accrue or
accumulate on sewage works carried out according to my plan, and the great
difficulty of disposing of sewage refuse is thus entirely overcome.
The effluent water produced by my process is pure enough to be used advantageously,
and especially for road watering, as it keeps the road longer in a moist state than
ordinary water and it lays the dust well; it may also be used for boilers and for
condensing purposes, and for various manufacturing purposes.
Having thus described the nature of my Invention, and the manner of carrying
out the same, I would have it understood that I claim,-
The composition of my precipitation mixture and my irrigation mixture, sub-
stantially as described.
And I also claim the disposal in an easy and inoffensive yet useful way of
the sewage deposit, substantially in the manner described.
In witness whereof, I, the said Fritz Hille, have hereunto set my hand and
seal, this Twenty-eighth day of September, in the year of our Lord One
thousand eight hundred and seventy-six.
F. HILLE. (L.S.)