Improvements in the Disinfection of Sewage, Waste Liquors, and the like.
Year: 1886

page_text: Date of Application, 31st Mar., 1886
Complete Left, 30th Dec., 1886.
Complete Accepted, 29th Mar., 1887
Improvements in the Disinfection of Sewage, Waste Liquors,
and the like.
I, FRIEDRICH PETRI of 70 Alexander Strasse, Berlin, in the Empire of Germany
Professor of Chemistry, do hereby declare the nature of this invention to be as
follows:-
The sewage or liquor to be treated is first led into a suitable channel for being
purified, at the beginning of which lime is added, and as the other end, that is, when
the lime has acted sufficiently magnesium sulphate is also added. From the latter
magnesia is precipitated by the action of the superfluous lime, which magnesia carries
down the solid matter suspended in the liquid.
In lieu of sulphate of magnesia, oxide of barium may be employed in the same
manner, this combines with the carbonic acid contained in the liquid and also with the
sulpuric acid of the sames to form a precipitate. Or peroxide of baryta may be
employed with still greater success, thereby also oxidising the organic substances in
the water. The Baryta may also be replaced by the slag of baryta produced by
calcining heavy spar, with chalk and pitch, this slag being lixiviated and the lye used as
addition to the liquid. Or the above may be combined as follows The liquid or sewage
is first mixed with caustic lime in the channel, and flows along the same until most of
the solid substances are precipitated, magnesium sulphate is then added, forming
precipitated hydrate of magnesia with the excess of lime, sulphuric acid being left in
solution. This reaction being complete, caustic baryta is added forming with the
sulphuric acid a heavy precipitate quickly carrying down all lighter suspended.
substances.
The liquid purified in this manner runs from the channel into a basin, in which the
precipitate is allowed to settle the same being subsequently removed and used for the
production of manure.
The liquid from the first basin is led into a second channel, and is first mixed with
chloride of magnesium, and also with the lixiviate obtained from a calcined mixture of
Wawellite, Amblygonite or other phosphate of alumina, with soda this forms with the

page_text: ammonia and ammonia-salts an insoluble precipitate which contains a great part of the
nitrogen from the liquid. The liquid containing the precipitate is led into a second
basin in which it is allowed to settle.
The liquid freed from the second precipitate is perfectly clear and almost inoderous,
but still contains traces of albuminates and is therefore led into a filter consisting of
gravel, coal, charcoal or other filtering material, mixed with crushed organic matter
containing containing tannic acid-such as saw-dust, dried and pulverised leaves, bark,
or the like. The substances containing tannin retain the albuminates in the water,
which latter after having gradually passed the filter, is free from organic impurities
and has the character of pure river water.
Dated this 31st dor of Morab 1000
COMPLETE SPECIFICATION.
Improvements in the Disinfection of Sewage, Waste Liquors,
and the like.
I, FRIEDRICH PETRI, of 70 Alexander Strasse, Berlin in the Empire of Germany,
Professor of Chemistry, do hereby declare the nature of this invention, and in what 2
manner the same is to be performed to be particularly. described and ascertained in
and by the following statement :-
The process of disinfection, forming the object of this invention is characterised by
the combined application of two or three processes, which take place in separate basins
and the result of which is the deliverance of the water from all putrifying and noxious 2
substances of these; two processes suffice for the disinfection the intermediate process
being a preparation for the second process.
According to my invention lime is first allowed to act on the sewage or other waste
water, magnesium or barium salts being subsequently added for the purpose of
precipitating the suspended substances such as soaps and fatty substances.
The final process consists in passing the liquid through an organic filter impregnated
with substances containing tannic acid (wood, hark etc) and has for its purpose the
deposit of the albuminates and also the general filtration of the liquid,

page_text: The second or preparatory process is added in order to preserve the filter containing
tannic acid for its special use in the final process, and consists in producing a separa-
tion of alumina from the phosphoric acid by melting Wawellite or Amblygonite or
any other phosphate of alumina with soda and subsequent lixiviation and obtaining
thereby an alcaline liquor which is added with chloride of magnesium to the waters
already purified by the first process.
The process is as follows:
I. The first stage of the disinfection is performed by-
a) The addition of lime and sulphate of magnesium which has for its purpose the
precipitation of the suspended substances contained in the sewage and of the fatty
matters, the addition of lime must be limited to prevent too much ammonia contained
in the suspended substances from being expelled which would impair the quality of the
manure to be obtained from the precipitate. The sewage or liquor to be treated is
first led into a suitable channel, at the beginning of which lime-water is added. At
the end of the channel, that is, when the lime has acted sufficiently, magnesium
sulphate is also added. From the latter, magnesia is precipated by the action of the
superfluous lime, and this magnesia carries down with it the solid matter suspended in
the liquid.
In lieu of sulphate of magnesium, oxide of barium may be employed in the same
manner, which combines with the carbonic acid contained in the lye and also with the
sulphuric acid of the same to form a precipitate which tends considerably to the
clarification of the liquid. Or peroxide of baryta may be employed with still greater
success thereby also oxidising the organic substances in the water. Commercial baryta
may also be replaced by the cheaper slag of baryta, produced by calcining heavy spar
with chalk and pitch, this slag being lixiviated and the lye added to the liquid. Or
the above reagents may be combined as follows: The liquid is first mixed with caustic
lime in the channels, flows along the same until most of the solid substances are
precipitated, sulphate of magnesium is then added, whereby, owing to the excess of
lime, hydrate of magnesium is formed and precipitated sulphuric acid being left in the
liquid. This reaction being complete when the liquid has advanced further down the
channel, caustic baryta is added, forming with the sulphuric acid a heavy precipitate
quickly carrying down all lighter suspended substances.
The liquid purified in this manner runs from the channel into a basin in which the
liquid is allowed to stand and the chemical action completed. The precipitate being
allowed to settle therein is subsequently removed and used in manure.
The liquid from the first basin is led into a second channel of further disinfection
from the ammonia still contained therein, the ammonium salts, and the albuminates of
albumino-ammonia etc. In this channel the liquid is mixed with chloride of magnesium
and also with the lixiviate obtained from a calcined mixture of soda with Wawellite,
Amblygonite or any other phosphate of aluminium. These minerals may be finely
ground and mixed with soda and heated in a lime furnace and lixiviated. The lye
and chloride of magnesium form with the ammonia and the ammonia-salts in the
liquid an insoluble precipitate which contains a great part of the nitrogen from the
liquid. The liquid containing this precipitate the production of which is considerably
accelerated by the alcaline nature of the liquids is led into a second basin in which the
precipitate is allowed to settle when it may be removed when required for manure.
The liquid freed from the second precipitate is perfectly clear and almost quite
inodorous but still contains traces of albuminates and is therefore subjected to a third
process of purification.
The liquid is led into a filter consisting of gravel, crushed charcoal, coal, or other
mechanically filtering material, mixed with crushed organic matter containing tannic
acid such as saw-dust, dried and powdered leaves, bark or the like. The filter acts
without the said organic and tannic additions, but not continuously; it can be
always regenerated by these substances. The substances containing tannin retain the
albuininates dissolved in the water which latter after having gradually passed the filter
is free from organic impurities and has the character of pure river-water,

page_text: The following table may be used as an indication of the quantities of the various
purifying agents employed in the foregoing process, for the disinfection. of 2000 parts
of sewage.
1 part of caustic lime suspended in 20 parts of water-(This quantity however
should be varied according to the nature of the sewage, so that 5 parts of solid matter
precipitated thereby may contain about 1 part of lime).
Sulphate of magnesia equal to 15th of the lime added.
Oxyide of Barium equal to 4th of the lime added.
Peroxyde of Baryta 14th part of the lime or of Lye from Baryta slag an amount
containing an equivalent quantity of Barium salts (to be found by analysis of
the lye).
Chloride of Magnesium th of lime before added Lye of Phosphate a quantity
sufficient to give 1 part of soluble phosphoric acid to every three parts of chloride of
magnesium added.
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed, I declare that what I claim is :-
For purifying sewage and other liquid waste:
1. The process consisting in treating the waste with lime and subsequently with
magnesium or harium salts, or with both, the liquid being afterwards passed through a
filter containing tannic matter, substantially. as illustrated and described.
2. The process consisting in treating the waste with lime; secondly, with magnesium
or barium salts or both; with phosphate of an alkali and chloride of magnesium ; and
passing the resulting liquid through a filter containing tannic matter, all substantially
as illustrated and described.
1000