River Pollution

River Pollution

An interesting lecture was recently given at the Manchester (England) Technical Laboratory by G. E. Davis, upon the above subject. According to an English contemporary the chair was taken by F. H. Walinsley, chairman of the rivers committee of the Salford corporation, who, in his opening remarks, said that though the state of the Irwell was bad now it would have been worse if the act of 1876 had not been passed.

Mr. Davis commenced by showing samples of neighboring streams which fed the Irwell—the colors varying from black to red—and said that the pollution had been increasing for over a quarter of a century, but the approaching completion of the Manchester Ship Canal made it imperative that something should be done to cleanse the river. Reviewing the act of 1876, he characterized it as a worthless measure, in that it made no, restrictions as regarded suspended matter or color. The clause providing for the discharge of chemical works etlluents into sewers was, in his opinion, a bad one. Treating with the various sources of pollution, sewage, he said, came first in point of magnitude. In Salford they had to deal with 10,OOJ.OOO gallons of sewage per day, and he showed by an experiment that to destroy the albumenoid ammonia chemicals would be required at the rate of 35 cwt. of alummo-ferric cake, or two tons of lime, per 1,000,000 gallons. Referring to the waste water from, the factories, he mentioned specially paper works, woolen mills, bleach, dye and chemical works, and stated that it was the users of the chemicals rather than the manufacturers who caused the pollution. The etlluents from chemical works consisted largely of calcium chloride, a salt in itself harmless to fish, but precipitation took place when this salt mixed with bleachers’ liquors in the bed of the river. There was no doubt that paper makers profited largely by the recovery of their soda, and he could instance works in the South of England where .£2000 a year was thus saved. No effort, however, had yet been made to deal with the acid sulphite liquors from the wood-boiling process.