A report to the Chicago Real Estate Board on the disposal of the sewage and protection of the water supply of Chicago, Illinois / by Messrs. George A. Soper, John D. Watson, Arthur J. Martin.

  • George A. Soper
Date:
1915
Catalogue details

Licence: In copyright

Credit: A report to the Chicago Real Estate Board on the disposal of the sewage and protection of the water supply of Chicago, Illinois / by Messrs. George A. Soper, John D. Watson, Arthur J. Martin. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    it can be made profitable in some instances by converting it into sulphate of ammonia. In winter it is difficult to dry septic sludge, but at Bir- mingham the drying area, which is 50 acres in extent, is gradual])- tilled up during winter as the sludge ripens in the tanks. Still the cost of providing additional capacity to tide over this season has to be taken into account, and for this reason the denser the sludge obtained the less storage is needed, and in this respect the deeper the diges- tion tank (within limits, of course) the better. 8.—FINAL DISPOSAL OF SLUDGE. The problem of how to get rid of fresh unsepticised sludge without creating a nuisance is not easy, and it is not less expensive as a rule where the quantity to be dis- posed of is large. Where the city is small and surrounded by arable land, the sludge may be got rid of in its semi-dry state by selling it or giving it to farmers, but on large works it is found that sludge accumulates to such an ex- tent when the season is unsuitable for farmers to lift it that they refuse to remove it unless well paid for so doing. Artificial and generally proprietory processes have succeeded in overcoming this to some extent by drying the sludge to a powder and storing it in bags until the farmer either has need for it or time to cart it away. Other methods of getting rid of sludge may be enu- merated as follows: 1. Spreading it on land, and digging it in as soon as it be- comes spadeable; 2. Trenching it, or running it into long trenches about 3 feet wide and 1 foot deep; 3. Lagooning, or simply filling up depressions, and allowing it to remain until it becomes, by thorough fermenta- tion, an inert mass; 4. Filter pressing; 5. Manufacturing into manure. Spreading sludge over land.—Where this has been done, the sludge has generally not been over 9 inches in depth. When allowed to remain until it has become suf-