CONSERVANCY METHODS.
The refuse to be removed from a house consists of fouled water, which
is at least equal in quantity to the water-supply of the house; the
excreta of the inhabitants; and “dust,” which contains, besides ashes,
considerable kitchen refuse; consisting of both vegetable and animal
matters.
In dry methods of removing refuse, the “dust” is often added to the
excreta, and the two removed together; or the “dust” may be separately
removed. In either case the foul water, and to a large extent the
urine, remain to be dealt with, and require special drains for their
removal. Thus in large towns, whether dry or wet methods of removing
sewage are adopted, drains for the removal of foul-water and rain-water
will be required, and it is found that they are practically as foul as
if they contained the solid excreta.
The dry methods of removing sewage involve a certain amount of
retention about the house; hence the general name of =conservancy
methods=. Of these the most important are—
1. The pail system.
2. The dry-earth system.
3. The midden or privy system.
=The Pail System= implies in reality the use of a movable cesspool.
The pail may be used alone, or may contain ashes and house refuse, or
some deodorant. Where the pail is used without any admixture of foreign
matter, it should be emptied daily, and care should be taken that the
pails for different houses are not exchanged.
In the =Goux System= the tubs are lined with a composition containing
clay and furnished at the lowest part with some absorbent material such
as chaff, straw, or hay, which serves to absorb the urine and retard
putrefaction. This is, when well managed, somewhat less offensive than
the ordinary pail system.
The pails may be supplied with a deodorant, such as sulphate of iron,
as at Birmingham, Leeds, etc.; they may be packed with absorbent
material, as in the Goux system (Halifax); the ashes and house-refuse
may be deposited in the same pail (Edinburgh, Nottingham); or coal
ashes may be scattered over the excreta (Manchester, Salford); but all
these systems are rapidly being superseded.
Although the pail or tub system is an improvement on the midden
system, it is necessarily a cause of considerable nuisance, and
its replacement by water-closets should be recommended in towns. In
detached country houses it may be retained without nuisance, if the
pail or tub is emptied daily, and its contents at once placed in the
garden beneath a shallow layer of earth. The pails in large towns are
usually collected in specially-constructed closed wagons. In some towns
the pail contents have been burnt in a “Destructor” (page 200) after
having been mixed with ashes. In other towns attempts have been made
to utilise the excreta, either by selling in their crude condition or
after drying and deodorising them by heat. None of these methods repays
the cost of collection. Mixing ashes with the excreta diminishes any
possible value they may possess as a manure.
=The Dry-earth System= is an important modification of the pail system.
In it dry earth or some other material is added to the excreta, thus
converting them immediately into an inodorous mass. Probably the best
contrivances for thus deodorising the excreta, as soon as they fall
into the receptacle, are =Moule’s or Moser’s Earth-Closets=.
It is found that 1½ lbs. of dry earth completely deodorise the
closet each time it is used. Loamy earth is the most valuable material;
a mixture of peat and earth or ashes is very good; sand, gravel, and
chalk are practically useless. It is necessary that the earth should be
very dry, and that it should be finely sifted. If the earth is damp,
decomposition of the excreta speedily occurs. The act of sitting and
rising works a hopper which scatters a supply of earth.
Charcoal and sawdust have also been used in connection with Moule’s
or Moser’s closet, and with good results. Charcoal has been obtained
cheaply for the purpose from street sweepings, and from seaweed,
as in Stanford’s closet, in which 1∕2 lb. of charcoal from seaweed
is used each time. Mr. Stanford found that while dry clay absorbs
only 4 to 5 per cent. of water, dry charcoal prepared from seaweed
absorbs 14·7 per cent. The best material, however, is dry earth, but
it must be thoroughly dry. The microbes in the earth disintegrate the
excreta, converting them into mineral compounds, such as nitrates.
Even the paper used disappears. Hence the same earth may be used over
again after being stored dry for six weeks. Whether the excreta of
an infectious patient are freed from infection by this process is
doubtful; if not, the infection might be scattered by means of dust.
The dry earth system is more expensive in use than the pail system, and
although applicable to villages and isolated houses, is quite unsuited
to large towns, owing to the practical difficulties connected with
the procuring and storing of dry earth. The dry earth closet requires
frequent attention, in addition to not being so convenient as the pail
closet; and there is much less manurial value in the contents of earth
closets than in those of pail closets.
The advantages of the earth-closet as compared with the water-closet
have been thus summarised by the late Sir Geo. Buchanan. “It is
cheaper in the original cost, it is not injured by frost, it is not
damaged by improper substances driven down it, and it very greatly
diminishes the quantity of water required by each household.” These
advantages only accrue when the system is perfectly worked, and do
not counterbalance the immense advantage and greater safety of the
water-carriage system in towns.
=The Privy or Midden System=, involving the use of a fixed receptacle,
is still prevalent in many towns as well as in innumerable villages.
In its worst form, the receptacle consists of a pit with sides of
porous materials, allowing percolation of filth in every direction;
and in this pit the excreta of whole households are allowed to collect
for months. It has been improved by providing a cover to keep out
the rain, and thus retard decomposition; still more by providing a
drain for the excess of liquid; and by making the sides and bottom
of the pit impervious to moisture. The addition of dry ashes to the
excreta tends still further to prevent any smell; and the greatest
improvement of all consists in raising the receptacle above the ground
level, and providing for easy cleaning from the back. The raising of
the receptacle involves a diminution in its size, and so prevents the
retention of putrefying matters near a house for a long time.
The model Bye-laws of the Local Government Board recommend a capacity
for the privy not exceeding 8 cubic-feet, the provision of means for
the frequent application of ashes, dust, or dry refuse; they forbid
any connection between the privy and the drain; insist on its being
at least 6 feet from a dwelling-house (too low a limit); and require
a flagged or asphalted floor at least 3 inches above the level of the
surrounding ground.
The _Nottingham tub-closet_ forms a link between the pail and midden
system. It is really a small movable middenstead, used for receiving
excreta, vegetables and ashes.
Even when carefully supervised, middens are almost certain to be
productive of evil. They possess two great disadvantages as compared
with pails or dry closets. (1) The time between collections of excreta
by the scavengers is much longer; and (2) the receptacle for the refuse
is part of the structure of the building, and cannot easily be renewed
when it has become saturated with excreta.
The use of pails or dry-earth closets is a great improvement on the old
middens, but even these compare very unfavourably with water-closets
in two respects. (1) The excreta require to be retained about the
house for a longer or shorter period, whereas with an efficient
water-carriage system, they are at once projected into the sewer. (2)
In removing the excreta, the weight of the receptacle has to be added
to that of the excreta, while in the water-carriage system, the water
serves as the means of transport.
In villages and isolated houses, where no drains are provided for waste
water, and the dry system of closets is adopted, the =disposal of waste
water= requires special provision. Very commonly the slops are thrown
out of the door, and soak into the ground about the house. They should
be carried by means of a waste-pipe into a water-tight cesspool, remote
from the house, whence they can be pumped into a field, or carried
away by special conduits.
=Relative Merits of Dry and Wet Methods.= No absolute answer can be
given in exclusive favour of either plan. Each is the best under
different circumstances; the dry method being chiefly suitable for
small villages, and for temporary collections of people, as in camps;
and the wet method for towns. The question of value of manure does not
enter into the problem, as it seldom repays for carriage.
The =objections to the water-carriage system= are really due to its
not being carried out in an efficient manner. When sewers are properly
laid; when they, as well as house-drains, are freely ventilated; when
house-drains are efficiently trapped and ventilated near their junction
with the sewer; when the drains are efficiently flushed, and the
outflow from the sewer is unimpeded, the objections disappear.
These objections are that—(1) the sewers, as underground channels,
transfer effluvia and the germs of disease from one place to another;
(2) pipes become disjointed owing to being badly laid, and the ground
is contaminated; (3) the water supply is in danger of receiving
impurities from the sewers. These objections do not hold good in
practice. The contamination of water-mains or of wells from sewers
implies gross carelessness in the method of laying of sewers or pipes.
The only objections which are of any force, are (4) that water-closets
require a large amount of water, and the sewage obtained is greatly
diluted, and consequently diminished in value; while (5) the disposal
of such an amount of water, in the case of a large inland town, is a
problem of the utmost difficulty. Modern engineering enterprise by
bringing water from a greater distance, and by aiding the discharge of
sewage when necessary by pumping, has overcome these difficulties.
There are many =objections to the dry methods= of removing excreta. (1)
Whatever dry method be adopted, the excreta are retained for some time
in or about the house, instead of being immediately removed.
(2) Although the initial outlay in closets and sewers is less than with
the water-carriage system, there is the constantly recurring expense of
removing the excreta, as well as of cleansing the pails, etc.
(3) In the dry-earth closets, the provision of dry earth or other
material involves some expense.
(4) Whatever dry method be adopted, sewers are always required to carry
off the foul water, as well as liquid trade products, and a certain
proportion at least of the urine. It is impossible to supply sufficient
dry earth to absorb all the urine and slops of the population.
Thus, as the Indian Army Sanitary Commission said, speaking of
barracks, “to have two systems of cleansing stations—a foul-water
system, and a dry-earth system—would simply be paying double where
one payment would answer; or, if all the excreta, solid and liquid,
are to be carried away, this must be done at a cost ten times greater
than that which would be necessary, if all the excreta were removed by
drains.”
With some of the dry methods, as where middens or cesspits are drained
into the sewers, the sewer-water is more offensive than in towns
supplied with water-closets. When a midden or cesspool is drained, the
principle of conservation, which distinguishes the dry system from the
wet, is practically abandoned; and not only so, but the solid matters
still remain to be disposed of, by a tedious process.
(5) The dry systems, involving the retention of excreta about the
house, poison the atmosphere. In all towns where the refuse matters are
not removed immediately, there is a high mortality, especially among
children.
On the other hand, the introduction of the water-carriage system into
large towns, with the abolition of midden-heaps and cesspools, has
been followed in nearly every case by a diminution in the death-rate,
and especially a considerable diminution in that from such diseases
as enteric fever. It has furthermore increased the comfort of life,
and removed those serious nuisances which are inevitably associated
with privies and pail closets, and to a less extent, when care is not
exercised, with earth closets.
HOUSE REFUSE.
In an ordinary household the disposal of ashes from fires, of broken
pots and cans, of waste-paper, and of vegetable and animal debris form
a serious difficulty. The difficulty is one that can be minimised by
the careful housekeeper. Old newspapers, etc., may be sold, though
their value is very small; other waste-paper should be burnt. All
vegetable and animal debris should be burnt. This may be effected
without nuisance if coal-fires are in use, by placing potato-peelings,
cabbage leaves and similar substances under the fire until thoroughly
dried, and then burning them. The careful housewife will not waste
bones, but utilise them for soup. After being boiled they are much less
liable to putrefy in the dust-bin; but should even now be burnt in
the fire. If this plan be pursued, the contents of the dust-bin will
be simply ashes, broken pots and cans, and a few cinders—here again
a sifter is desirable—and no nuisance can arise. _It is only organic
refuse that smells._ If only gas or paraffin stoves are in use, as
during the summer months, any possible nuisance in connection with
the dust-bin is minimised by allowing all refuse to dry before it is
placed in the dust-bin, or by wrapping all putrefiable substance inside
several layers of newspaper.
In _emptying the dust-bin or ash pit_, care must be taken that the
bottom is thoroughly scraped out. It is well to keep some quicklime
(thoroughly dry) for sprinkling on the bottom and sides of the
receptacle each time after it is emptied. This greatly helps in keeping
it dry and diminishing nuisance during summer.
In many households a separate receptacle is kept for what is known
as “hog-wash,” containing waste-food, often in a foul and putrefying
condition. In well-ordered households, except in hotels and similar
establishments, there is no necessity for a “hog-wash” tub, and its
presence argues wastefulness and carelessness. Food which cannot be
eaten because it has “gone bad” should be burnt.
Two forms of receptacle are used for house-refuse, an ash-pit or a
dust-bin. An =ash-pit= is a fixed receptacle for the reception of
house-refuse. In many towns the same receptacle is used for excreta.
Then we have a privy or privy midden, according to size (see page 196).
Ash-pits for household refuse alone should be small, so as not to hold
more than a week’s refuse. No part should be below the ground level.
The floor and walls should be lined with impervious smooth cement, and
the ash-pit should have a hinged cover to keep out rain, and a door on
one side to facilitate emptying. The ash-pit should be at least six
feet distant from any wall of the house. Even the best constructed
ash-pit is as much worse than a dust-bin, as a privy is worse than a
pail closet. A fixed is always less easily cleansed than a movable
receptacle.
A =dust-bin= is usually made of galvanized iron with a tight-fitting
lid. This receptacle can be kept clean, and can be carried without any
transference to another tub direct to the cart.
The =removal of house refuse= constitutes an important part of
municipal work. In most towns it is carried out weekly, sometimes less
frequently, while in some towns removal twice or three times a week is
secured. A daily removal is carried out in a few towns, and this is by
far the best plan, as decomposition and the dangers associated with it
have then no chance of becoming serious. The house refuse should always
be conveyed through the streets in covered carts.
The =disposal of house refuse= constitutes a problem of increasing
difficulty. Unfortunately in the suburbs of many towns it is deposited
on low-lying land in disused quarries and brickfields. When land has
been thus levelled, it often next appears as “an eligible building
site.” A very common practice has been to excavate gravel and sand upon
the site of proposed dwellings, and allow the excavation to be filled
with dust-bin refuse. Before building on such a soil it is necessary
to excavate down to the virgin earth, and to render it impervious by a
layer of cement concrete.
A second method is to _sift and sort the refuse_, separating by
means of sieves the finer ash and dust from the coarser parts. This
is usually carried out in a large dust-yard adjoining a river or
railway-siding. The “breeze,” consisting of cinders and coals, along
with the fine ash, are sold to brickmakers; the “hard core,” consisting
of clinkers, broken crockery, etc., is used for road making; and the
“soft core,” consisting of animal and vegetable refuse, to which is
often added stable manure, is sold for manure. Iron, tin, paper, rags,
bottles, and corks are separately collected and sold. This disgusting
process, often carried on by women, is now gradually being disused.
A third method is to _cremate the house refuse_. This has been done
to a large extent by burning the house refuse for making bricks
(page 124). This method of slow and imperfect combustion necessarily
involves a nuisance. A more elaborate means of securing the same
end is by the modern =Destructor=, which has been gradually brought
towards perfection. A destructor is a large furnace, in which, after
the fire has been first lit, the combustible matter in the house
refuse suffices to keep it alight. Various mechanical devices are in
use for emptying the trucks of house refuse on to the fires without
handling it, for clearing out of the fire the inorganic refuse, and for
ensuring sufficiency of draught. The amount of draught has in the older
destructors been dependent upon the height of the chimney. In some
more recent destructors the same end has been more efficiently secured
by injecting a steam blast into the furnaces. A temperature of about
2,000° F. is reached in certain parts of the destructor, the rapid
draught ensuring enormous heat. In view of the possibility of a portion
of the smoke not being completely burnt, a second “fume cremator” is
often provided, through which the products of combustion in the furnace
are passed. The fuel in the “fume cremator” is coke. Besides incomplete
combustion of combustible material, which is rare when the fume
cremator is provided, the escape of fine dust up the chimney requires
to be guarded against. This is partially prevented by ledges near the
bottom of the chimney. In a destructor the house refuse is reduced
to about one-third of its original bulk, the residue being innocuous
clinker, metallic refuse, and dust. This material can be utilised for
making roads, and in the manufacture of mortar. The waste heat of the
destructor has been partially utilised for various purposes. This
method of disposal of house refuse is usually the best available for
large towns, and offers the additional advantage that no nuisance is
caused by the deposit of offensive material in neighbouring districts.