At Meerut for the year 1911–12 the sale-proceeds of night-soil and city sweepings amounted to Rs. 12,871, and at Furrakhabad cum Fatehgarh to Rs. 18,317.
Allahabad Shallow Trench System.
The area required for the contents of a 60–gallon conservancy cart is 80 sq. ft., the most suitable dimensions being 16 feet long by 5 feet wide; 3 inches of the top surface of this space is removed and placed on the embankments of the plot near which the first line of trenches is dug; the subsoil thus exposed is then well cultivated and pulverized to a depth of 9 inches, when the contents of the cart are tipped into the centre of the trench; the liquid matter rapidly sinking into the loosened soil, while the solid excreta remains on the top in a layer less than ⅛ inch in thickness; 3 inches of earth are then similarly removed from the next trench which is parallel to the first, no intervening space being left, and thrown over the night-soil in the latter. The practical working is very simple, as all that has to be done, is to see that a sufficient number of trenches for the daily supply are dug the day before and the earth from them placed over the filled ones. It has been found from experience that night-soil, thus treated, decomposes in less than a week and, if dug then, no trace is observable; the effluvium disappears after three days, and crops are successfully grown immediately after trenching. The Shallow Trench System is by far the most scientific one, but requires a large area of land, working out to 545 sixty-gallon carts per acre. At Muzaffarpur during 1912–13, part of the night-soil was sold for Rs. 1,200, and part of it trenched in the municipal trenching ground, which was leased out for Rs. 1,045. The practical objection to this system is the fly pest. It is therefore only applicable where the trenching grounds are remote, and to the leeward side of the town. Sprinkling chloride of lime or quicklime on the top of the trenches prevents the breeding of flies. The researches of Majors Firth and Horrocks, R.A.M.C., published in the British Medical Journal, however, show that the enteric bacilli is capable of surviving in soil for much longer periods than has been believed possible. These can exist apparently in ordinary soil for 65 days, in sewage-polluted soil for at least 53 days, while in soil sufficiently dry to be blown about in dust for 25 days, and for about a similar period when exposed to a hot summer’s sun. The authors of this note have also proved experimentally the translation of infective material from sun-dried and dusty soil by means of wind, as also by flies which have walked over or fed on polluted earth, indicating the advisability of treating night-soil, especially from Military Cantonments, in septic tanks and filter beds before applying it to soil—vide Chapter IX, page [50].
Area of Trenching Ground.
In order to arrive at the area necessary for a deep trenching ground for a bazaar of 10,000 inhabitants, and assuming that not more than ⅛th of a gallon of night-soil per head per diem is removed, provision will have to be made for 1,250 gallons or, say, 200 cub. ft. If the trenches are made 1 foot wide, 1 foot deep, and 1 foot apart, and are filled with 6 inches of night-soil, 400 cub. ft. will be required daily, or allowing for roads and divisions between the plots, say 12 acres, for a year’s work, or, in other words, the area required is, one acre for 833 persons. The trenches should be divided up into plots or sections for each latrine circle, excavated, when weather permits, at least a week before they are used so as to aërate the earth; the bottom of the trench should also be dug up to a depth of 9 inches for the same reason.
The following extract describes somewhat forcibly what may, and undoubtedly does frequently occur in many instances:—
“Trenching again is a success in dry soils, but a good deal of ground is required, and sufficient trenching ground is not always available within practically workable distances of the night-soil producing areas (public and private latrines), and often enough, whereas it may be quite successful in a given ground in the hot weather, it will, in the same ground, however fresh, prove an absolute failure in the rains, when, owing to the high water-level in the subsoil, everything trenched is brought to the surface by the gases of putrefaction, and the entire area trenched becomes a pestilential bog, crawling with maggots, bubbling with the foulest odours and swarming with blue-bottle flies, whose chief delight is to frequent the houses in the neighbourhood and infect both food and drink.”
CHAPTER VIII.
Collection and Disposal of Refuse.
The scavenging of a town and the disposal of the refuse has probably more effect on its sanitary state than anything else; dirty rags, dead grass and other refuse lying about, are ideal homes for germs of disease to live and flourish in, and these, when a shower of rain falls, very frequently get washed into the water-supply. The modern system of cremation in specially constructed incinerators is the only safe method of disposal of town sweepings. Even in England, where the water-supply is, in the majority of cases, not affected, careful observations have proved that there is an increased liability to enteric fever in the localities of refuse heaps. In an Indian bazaar dependent on wells and tanks for its water-supply, anything more barbarously insanitary than the filling up of deep tanks with town refuse is hard to imagine. Deep burial keeps the germs of disease alive, probably for years, in the very stratum the drinking water is frequently taken from.
Dust-bins.