Disposal and purification of factory wastes or manufacturing sewage / by H. W. Clark.

Date:
1910
Catalogue details

Licence: In copyright

Credit: Disposal and purification of factory wastes or manufacturing sewage / by H. W. Clark. 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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    fifteen to twenty minutes in a machine like a paper-machine washer, and carbonate of soda was stated to be added in quantities sufficient to neutralize the acid. Other rags were treated by a process in which a warm ammonium chloride bath was used instead of a bath of sulphuric acid. The rest of this second process was practically the same as that just described, except that the washing was done without the addition of sodium carbonate. Only a small amount of the stock underwent this second treatment, however, when it was desired to keep a black color. The wastes were supposed to be neutral or slightly alkaline on ac- count of the addition of sodium carbonate, but it was soon evident that the waste when discharged was still generally acid. The waste as it came from the mill contained a small amount of matter in suspension, which settled very rapidly, leaving a clear liquor. This clear liquor was passed through a sand filter at the experiment station, first at the rate of 100,000 gallons per acre daily and later at a rate of 150,000 gallons per acre daily, with a satisfactory, well-nitrified effluent as a result. Before application to the filter the acid wastes were neutralized by the addition of lime in order to ensure good purification. The following table presents the average analysis of the waste as it came from the works, after clarification by sedimentation, and of the effluent from the filter: — Average Analysis of Raw Waste, Waste applied to and Effluent from Filter. [Parts per 100,000.] Color. Ammonia. Chlorine. Nitrogen as — Oxygen Con- sumed. Hard- ness. Free. Albumi- noid. Nitrates. Nitrites. Raw waste, - .9483 .4087 - - - 3.05 - Applied waste, . - .8000 .1280 3.15 - - 1.02 12.95 Effluent, 0.23 .0836 .0592 3.93 1.28 .0022 0.79 1.45 Glue Wastes. Experiments were made during 1908 and 1909 upon the wastes from a glue factory. The stock used at this plant was of three kinds, consist- ing of two grades of salt stock (fish skins, heads and bones) and fresh fish heads. All three grades were washed before use. After being washed, the best grade of salt stock was cooked in open kettles, while the poorer grade of salt stock and the fresh stock was heated with live steam in closed iron digesters. The results of the cooking in each case consisted of glue liquor and a solid residue. The glue liquor was evaporated and treated in various ways to form the finished product, while the solid