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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    Effluent from Filter receiving Hotted Liquor. [Parts per 100,000.) Ammonia. Nitrogen as — Oxygen Consumed. Free. Albuminoid. Chlorine. Nitrates. Nitrites. .0694 .1134 7.30 3.75 .0075 1.66 Sedimentation. When wool-scouring liquors are allowed to run into settling tanks, a considerable portion of the matter in suspension, such as sand, mineral matter, etc., washed from the wool, settles out. It is probably true, judging from our experiments, that in no case will more than 30 per cent, of the organic matter in suspension settle out within any reasonable length of time. Generally the percentage is not as ]arge as this, inas- much as the soapy and fatty matters present have a tendency to float and to hold up other matters in suspension. Chemical Precipitation. In the experimental treatment of these wool wastes about all the common precipitants were used, such as lime, ferric sulphate, ferric sulphate and lime, iron alum, aluminum sulphate, ferrous sulphate, ferric chloride, calcium chloride, etc. In all these experiments it was shown that a large amount of precipitant was needed to cause any coagulation whatever. Varying amounts of alum up to 30,000 pounds per million gallons often had little effect, and the same can be said of the addition of ferric sulphate. When ferric sulphate and lime were both added the amount necessary to cause a fair coagulation and pre- cipitation was somewhat less. Treatment of some of these wastes with sulphate of alumina, at the rate of 50,000 pounds per million gallons, caused no precipitation beyond that given by sedimentation alone. With ferrous sulphate and ferric chloride some precipitation could be obtained by using 15,000 pounds per million gallons. Calcium chloride was more efficient than any of the other precipitants, but at least from 10,000 to 20,000 pounds per million gallons had to be used with a strong liquor. In the use of this precipitant the filtrate after precipitation was generally almost odorless. The failure of precipitants to cause any satisfactory coagulation and precipitation of wool-scouring liquor, except when added in excessive amounts, is due to a number of causes. Inasmuch as the amount of
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