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6. Permanganate of potassium is a crystalline salt-like substance of a purple colour, in the preparation of which only mineral substances are employed.

FIG. 4.

Well Top

FIG. 5.

FIG. 6.

7. Put one or two ounces of the solid substance into a dol, or bucket, which has been filled with water drawn from the well about to be treated. Stir it up, and pour the red solution thus produced into the well, leaving the portion of permanganate that is not yet dissolved at the bottom of the dol. Lower the dol into the well, fill it with water, draw it up, pour back the water as before, and repeat the process till all the permanganate has been dissolved. In all cases enough permanganate should be added to produce a faint red colour lasting for 24 hours.

8. If the water in the well is bad, more permanganate will be necessary. In such a case it will be found that the strong red colour at first produced quickly changes to brown, and then fades away. This is because the permanganate destroys dirt and is destroyed by it. Therefore, if the water in the well is clean, a smaller quantity of permanganate will be necessary. From one to four ounces of permanganate will be found to be enough for ordinary wells. If more permanganate is added than is enough to produce a faint permanent red colour, it is likely that frogs, that may be in the well, will be killed. This will, in a few days, give the water a putrid taste. If the quantity of permanganate is not enough to produce a faint permanent red colour, it is unlikely to do good. If possible, the permanganate should be added at night, in order to leave the wells undisturbed as long as possible. The water will be fit to drink on the following morning. If then a red colour is still present, the water may have an unpleasant taste, but it is perfectly harmless.

Figure 4 is an illustration of the latest pattern of well adopted.

New Wells.

When a new well is proposed, and local conditions are suitable, a safe form is that designed by Dr. Cameron of Wigton, N. B. This arrangement is shown in Fig. 5. The well should be in the centre of a reserved area of at least 20 yards in diameter, and the lead pipe leading from it to the pump must be fitted by brass screw joinings. This is a suitable design for the vicinity of cutcherries, where an open space for a reserved area is generally available.

Another excellent design for a new well, and one more generally suitable, is shown in Fig. 6. This prevents any danger of the water being contaminated by dirty vessels being lowered into it for the purpose of drawing water.

FIG. 7.

Tube Wells.

Tube wells answer admirably in many localities; it is, however, always essential to have a bore hole made first to determine the stratum which has to be tapped, as the point of the tube may be easily driven through this. An improved form of pump is shown in Fig. 7; this obviates the danger of impure water being put in the mouth of the pitcher spout pump in order to make it draw.

The great advantage of tube wells is that they enable a stratum, underlying that of impermeable stiff clay which exists in many cases, to be tapped, thus avoiding the danger of contamination by subsoil water. The supply from a tube well is, however, limited in quantity.

Where wells are founded on a clay stratum their efficiency can generally be largely increased at a trifling cost, by driving a pipe lined boring down until water-borne sand is met. Great care must, however, be taken that, when the boring is going on, this stratum be not passed through, and constant tests of the discharge obtained at the various depths are therefore necessary.

Water drawing utensils.

In all cases it is advisable either to provide a pump on a public well, or iron buckets with light chains and wooden pullies, so that private water drawing vessels be not lowered into the water. The pump should be fixed on the platform surrounding the well, and not on the top. A light corrugated iron roof over the mouth of a well is also useful in preventing leaves, and other impurities falling in, and also in affording shelter to the water-drawers.

PLAN OF DOME FOR WELL

FIG. 8.

An effective and economical well cover designed for Ranchi is shown in Fig. 8, page 11. This, for a 8′ diameter well, costs about Rs. 90.

Tanks.

A large proportion of the water-supply of a Municipality is usually taken from tanks, into most of which the drainage water from the neighbouring vicinity is washed during the rainy season. This can be prevented by raising the banks. The sullage water of a bazaar is indescribably filthy, and if in-drainage is prevented the tanks will fill up by percolation as the level of the subsoil water rises—a bad enough source of supply, but infinitely purer than the surface water combined with filth from a crowded area. The excavation of new tanks in a Municipality should be discouraged as much as possible, and attention paid to conserving the existing ones. Small pumps and masonry platforms for washing purposes draining away from the tanks will improve matters. In the late Mr. A. E. Silk’s book on “Municipal Engineering in Bengal” the following classification of comparative purity of water-supply is adopted:—

1. Deep spring water.

2. Subterranean or deep well water.

3. Upland surface water.

4. Subsoil water. (If distant from any collection of houses).

5. Land springs.

6. River water.

7. Surface water from cultivated land.

8. Subsoil water under villages or towns.

Surface water from a bazaar is classified as sullage.

FIG. 9.

Where tanks are used as a source of drinking water-supply, they should be properly fenced and conserved, and the water drawn by a pump. Recent researches have proved that polluted water, if stored in a tank or reservoir where it can be preserved from subsequent contamination, rapidly becomes pure. The Type plan, approved by the Sanitary Board of Behar and Orissa, is shown in Fig. 9, page 13. This for an existing tank of 100 yards square area is estimated to cost Rs. 2,700. The pumps, provided in duplicate, are Kite double action pattern and cost about Rs. 425 each. The fencing provided is the Ideal Woven wire fence, 10 strands, 48″ high, and can be fixed at about 12 annas per yard.

Another and a cheaper method is shown in Fig. 10, page 15. Here the tank is completely fenced in with the exception of an entrance to a platform which extends towards the centre of the tank from which the water can be drawn by hand. Model rules for clearing out and re-excavating tanks are as follows:—

Excavation.

1. Tanks should be cleared out and re-excavated during the dry weather months when the level of the subsoil water is at its lowest. Work should be commenced in January or February and completed before the middle of May, but these dates must depend more or less on the locality, as in some parts of the Province the prevalence of heavy thunderstorms in May might make it advisable to complete the work before then.

2. The re-excavation, until water-level is reached, should be carried out in regular layers of 1 foot in depth, an offset of 1 foot being left on the bank side for each layer. This, when dressed off, will give a regular side slope of 1 to 1 to the tank. When water-level is reached, if it be considered necessary to excavate below this, and if pumping machinery to dewater the tank is unavailable, the area must be divided up into compartments of suitable size, separated by bunds, one, or more of which, can be dewatered by bailing into the adjacent ones, when the excavation can be continued to the required depth, the other compartments being similarly treated in turn.

TYPE DESIGN FOR FENCING IN TANKS

FIG. 10.

Disposal of Spoil.

3. The spoil from the excavations should be placed on the outside of the embankment formed round the tank when originally made, and should be deposited in such a position to preclude, as far as possible, its being washed back again by rain water.

Dressing and Turfing.

The crest of the embankment should be dressed off to a slope of 1 in 12 away from the tank, with side slopes on the outside of 2 to 1. This will prevent direct contamination of the tank by spill water from the crest, where persons or carts, may have encamped.

All slopes should be neatly dressed off; all those above highest water-level being turfed during the commencement of the ensuing rainy season. This is very important as it prevents the chance of a considerable quantity of the excavated earth being washed back into the tank.

Water-supply for Municipal and Rural areas is a subject which is, at the present day, receiving much attention. It is being encouraged by contributions from Government and from Local Authorities, by gifts from wealthy Indian gentlemen, and by loans from Government redeemable in a fixed period. For rules for the preparation of projects in the Province of Behar and Orissa see Appendix F, page 69, and for the table of instalments for the repayment of loans, Appendix E, page 68. The comparative death-rate from Cholera and Intestinal diseases in Municipalities which possess a pipe water-supply, and those without, need only be glanced at to prove the vital importance of a pure water-supply, and even these figures do not adequately indicate the true position, as further loss of life due to water-borne diseases, cannot be traced out from the statistics published. Major S. A. Harris, I.M.S., Sanitary Commissioner, United Provinces, in his paper on the effect of a pipe water-supply on the reduction of Cholera in urban areas, read at the Second All-India Sanitary Conference at Madras, in November 1912, quotes the reduction of death-rate per mille before and after the provision of a pipe water-supply for the following places:—

	Before.	After.
Dehra Dun	10·19	2·25
Meerut	7·49	3·02
Naini Tâl	10·19	2·86

and stated that the number of years in which the Cholera death-rate rose above 1 per mille is seen to have been reduced by the filtered water-supply to about ½ in Dehra Dun, Meerut, Benares, Lucknow and Naini Tâl.

The cost of Water Works must vary considerably according to local conditions. Where the supply is derived from a source not liable to contamination, from spring wells, tube wells and infiltration galleries, where subsequent filtration is unnecessary, the capital expenditure may vary from Rs. 3 per head for a tube well, Rs. 4–8 from an infiltration gallery supply, such as Congeeveram (Madras), to Rs. 10 and over for a filtered water-supply derived from a river. The cost of the distribution system must necessarily vary according to its size, and the density of population in the area served, but this, under normal circumstances, may be assumed at 50 per cent. of that of the Water Works. As each Province in India has a Sanitary Engineer, and as the subject of the preparation of a Water Works project is a highly technical one, it is beyond the scope of this work to go further than to impress its importance. Any efficient Water Works started means a large saving of human life and of much misery.