The Roanoke times. [volume] (Roanoke, Va.) 1890-1895, 1892-09-29
SEWAGE OF LONDON.
1T is TAKEN OUT TO SEA AND SCAT
TERED OVER THE WAVES.

Method OF Separating the SIudge from
tho Emuont-Clean Ships.
"Oh. how unpleasant The idea of go
ing to sea with sludgel" On the con-
trary. you know nothing of it. The
deck Of the sludge ship is broad and
clean; the deck house or saloon" small
but comfortable; on the bridge q fresh
breeze Is blowing; the sunlight sparkles
brightly on the rufiied surface of the
river, and you scarce can realize that
this fine steamer is carrying thousand
tons Of London sludge out to sea. Yet
such Is the fact The idea that the
mud barges" of the county council,
which take out tho precipitated portion
of London sewage to the Barrow deep,
are simply dirty dredges is quite mis-
take. They are powerful twin screw
steamships. worked by two sets of triple
expansion engines and fitted with three
large tanks, kept covered. and abso-
lutely free from nuisance to anybody,
even to the sesmen on board. They can
make two triHs out to SEQ In every
twenty-five hours, steaming about ten
knots, and, as 9 matter Of fact, they
thus dispose Of ii 900 IONS Of sludge in
q week.
The sludge Is precipitated by treat
Ing the sewage with lime and sulphate
OF iron. First, six huge cages catch
debris, such as sticks and dead rats and
cells. ETC., in the great rushing sewers
which drain London. This rubbish is
burned in destructors ut the rate OF
something Ike hundred tons week;
then the black river Of sewage is stirred
In tanks with ltme-or, more correctly.
lime water-in the proportion Of about
815 grains to the gallon. The effect Of
the lime is to precipitate matter in sus-
pension and solution and also to deodor-
lie. You may take smelling bottle
with you If you like, but with plenty OF
hme about you will hardly need it. But
walking on along tho top Of the twenty
seven feet wide sewer, which ia probably
TO become beautiful boulevard for
Barking. one comes to tho sulphate of
iron shop" where 800 tons at a time
are received, and where. after being dis
solved in the proper proportion as di-
reoted by the chemist In charge, it, too,
finds Its way to the swift river Of sew
age.
But then comes pause in the rivor's
mad career. 1t is admitted through the
Penstock chalnber-that is, building
with number of iron gates-to set OF
covered preciptating channels, whore it
can leisurely mediate after Its wild
rushings from London. Here in its
quiet bed the limo aud iron, in casting
down the solid portions, can take full
eject. and the clear portion Of the liquid
at the top-now called the eff1uent-
Is let oH over the head OF wall at the
end Of the chamber to channel at tho
other side; whence, gathering speed
again 1T PUSHES 30 reservoir, from
which ut ebb tide 1t joins the Thames.
The siudge passes through pipes from
the bottoms OF the precipitating cham
bers to another reservoir, whence 1t is
pumped to the tanks in the sludge
ships and conveyed 30 SEQ.
The effect ON the river Is most satis-
factory. On the testimony of the har-
Dor master it is cleaner now than it has
been for some years. while Mr.. Thudi-
chuln. the chemist at the Barking 'out-
fall' works, joyfully maintains it hos
% per cent. Of oxygen, which it has not
ze5ojoed in for some summers past. But
the clean foreshore and the scent of sea-
weed at Barking, and tho much purer
looking water In tho Thames itself. are
proofs to the uninitiated Of the success
Of the new" system.
That system Is only now getting into
full working order. The county coun-
cdl have added two moro ships to the
fleet; making now five in all; and they
are conveying some 40 900 tons Of sludge
out to sea every week. Four ships are
constantly at work day and night, and
one takes its turn Of q rest week for
painting, repairs, etc., and affording a
lighter time for the men. These arc
sailors, and sleep on board, regular
watches being kept. except one twenty
four hours in every seven days, when
they are allowed of duty.
The discharging ground Of the Steam
ers Is the Barrow deep, como miles be-
yond the More light The deep is an
unused channel. the north bound vessels
taking course considerably to the left
and southward ships far to the right.
The channel has been buoyed by the
council. and NO captain may commence
discharging until he has passed the
North Knot buoy. The discharge Is
quickly effected by opening valves in the
vessels bottom; the principle being
much the same as that used on the self
emptying lifeboat-which, indeed, is bat
en- adaptation of the law that water finds
its own level. the bottom of the tanks
being built ON level with the sea. The
valves are easily opened from the deck,
and 30 quick is their action that the
whole Thousand tons can be discharged
IN seven minutes Generally the time
occupied. however, Is longer, the vessel
perhaps steaming ten miles while empty