Evening star. [volume] (Washington, D.C.) 1854-1972, 1893-01-13
HOW TO DISPOSE OF SEWAGE.
An Interesting Lecture by . Civil Engineer
Before the Brooklyn Institute.

From the Brooklyn Eagle January 10
Mr.. J. Foster Flagg. a member Of the Ameri-
can Society of Civil Engineers, delivered an in
teresting lecture before the engineering depart
ment of the Brooklyn Institution Of Arts and
Sciences, in the large lecture room Of the
Y. N. c. A. building, last night, on "Ths Dis
posal of Sewage by European SYSTEMS" The
lecture was illustrated by lantern photographs,
specially prepared by Mr.. Flagg
The lecturer has recently spent year IN Eu-
rope and has taken the opportunity to visit num-
Der Of noted works for the disposal of city sew
age, both in England and on the continent In
his lecture he first gave = general account Of
the different modes of removal Of household
sewage from the centers of population and Of
the leading methods pursued in its publication
and disposal and then gave some notes of the
| working of these methods at some of the places
he visited He said in part:
The water carriage system of transportation
| OF household sewage, which has not been used
| to any great extent until within a comparati lively
recent period, is certainly the cleanest and most
convenient Of any. In the United States II is
! practically the universal method Is the prin-
| cipal one in England and its use 10 being largely
extended on the continent especially in Ger
many. An interesting modification Of this sys-
| tenn, where pumping is necessary, IL the Shore
! Hydro Pneumatic system, by which the pump
ing can be done from number Of stations,
! eCattcIcO over u CbN, Oy selI-HCtlng electors,
located in chambers beneath the streets and
worked from a single power station by COM
| pressed air. This system has been adopted for
the Columbian exposition IN Chicago. where the
ELECTORS will have a combined pumping cap &C.
ity of 1000. 900 gallons in twenty-four hours
The different methods Of disposal Of sewage are
as follows: l. Discharging the crude sewage into
a neighboring water course, lake or harbor-
still much the most common method in Amer
lea. H. Chemical precipitation Of the insolu-
bic and also some percentage OF the soluble
constituents OF the sewage. I'LL Publication
| by broad irrigation on neighboring FARMS w.
| Publication by intermittent downward filtra-
| ton, requiring a sandy soil. This method has
| generally been preceded by natural or chemical
/ precipitation. but recent experiments made In
| England and on a more extended scale at Law
renee, Mass, show that with properly con-
| structed beds previous precipitation is unneces-
| sary. The eiuent from either of the last three
methods of treatment flows to the nearest water
course. The first method has caused such a
fouling Of streams in the densely populated
country OF England, with its small water
courses. as to compel some treatment of the
town sewage before discharging il into them a
notable example OF which is at Coventry where
| the dry weather flow of the only available
stream is sometimes only one-half that of the
sewage discharged from the town. As the con-
sumption OF water in English towns is much
less than in this country the sewage of
Coventry. after being mixed with the low
water flow OF the river, is still fonl as ordi-
nary American sewage. The same necessity
for publication, though in a less degree is being
felt III Massachusetts, and some other parts
OF our country. Chemical precipitation is
sometimes effected by lime, in the form of milk
OF lime alone, but preferably bv some salt Of
alumina or ferrous salt used in conjunction
with much smaller amount of milk Of lime.
Works using the B C process (clay, charcoal
and alumino ferric) and the recent ferrozone
and polarite process. which were visited as
well as the more ordinary methods. In the
latter process the ferrozone. which is used as a
precipitant Is composed principally of ferrous
sulphate and magnetic oxide of iron: after pre-
ciptation the effiuent from the settling tanks is
cleared by passing it through a filter of COM
parativelv exceedingly small dimensions one Of
the ingredients of which is polarite more than
half composed of insoIuble porous msonetic
oxide of iron, which deodorizes and nurifes the !
efiuent without becoming oxidized itself. The
most important example of broad irrigation is !
at Berlin Here the sewage of GOO 600 persons
is constantly pumped I'D and delivered To farms
six and twelve miles from the CITY. having an |
area of nearly - 500 acres where il il used for |
irrigation. Large crops of varied character
are raised from these farms The sewage ia |
pumped from twelve pumping stations in the |
twelve different districts into which the citv ia
divided. These pumping stations are well de- |
signed and exceedingly well managed. and |
although many of them are in the heart of the |
city quite free from any cause of offense to |
the nelgnOOrnOOd. IL Is not generally cOnsld- |
cred that the sewage Of more than one hundred |
persons per acre can be treated by this method |
The process Of intermittent filtration the heat |
methods of working which have been SO care |
fully and thoroughly investigated at the Law
renee experimental station, requires much less |
area than broad irrigation. the most suitable |
soils being capable of purifying the sewage of |
1000 persons or more per acre. This mode of |
treatment is not, correctly speaking one of FL |
tration but is biological process, the purifi- |
cation being accomplished by organisms known |
as nitrifying bacteria. The sewage is applied to |
the filter beds at such intervals and in such |
quantities will allow it to sink thoroughly |
into the material of the bed and also allow to |
enter its pores a fresh supply of air. the oxygen
Of which is so necessary for the offensive de- !
composition of the organic compounds by BAG
terial action. The publication by this method |
is decidedly the most perfect of any, with fl
ter of fine sand five feet in depth, the efiuept |
being as free from organic matter and bacteria
-. "eo " ohenio1i Pfecipitauon