GB191418564A - Improved Process of and Apparatus for Treating Sewage or other Putrescible Matter. - Google Patents

Abstract

18,564. Landreth, C. P. June 9, [Convention date]. Liquids, treating; treating surfaces.-Sewage, effluents from tanneries or slaughter-houses, and other putrescible liquids to be electrolyzed are treated with a hydrate such as lime, soda, or potash, in sufficient quantity to ensure alkalinity after the electrolysis. This alkalinity should be at least great enough to be indicated by phenolphthalein. Parallel electrode plates E of carbon or iron or other metal may be used. Iron electrodes are not attacked provided that sufficient alkali is present; the amount of alkali required for this purpose increases with the current density. High current densities may however be used so that hydroxide acting as a precipitant is formed from the anodes. The alkali, preferably milk of lime, is pumped or run from a tank 10 into a preliminary settling-tank 2 or a pipe 7 through which the liquid to be treated passes to the electrolytic vat, or the alkali may be run directly into this vat above the bottom set of electrodes by a pipe 22. In the last case, the lowest electrodes may be of carbon and serve for preliminary electrolysis to produce nascent oxygen or hypochlorites, chlorides being added if required. Sewage may be broken up by a rotary pump, and by paddles p, p', Figs. 1, 2, and 4, between the electrodes. The paddles may be mounted on shafts s made up from short pieces coupled together. Each paddle may have a boss extending through an electrode into a countersink in the next paddle. After electrolysis, further settling takes place in a tank 9, the effluent from which can be run into a water course, while the sludge, together with solids from the preliminary settling-tank if desired, is pumped into a filter press 17. The filtrate can be either returned to the preliminary tank 18, or mixed with the effluent in a pipe 14. Solids from the preliminary tank may alternatively be disposed of by usual methods. The sludge may be treated with sulphuric acid and used as a manure, or may be burnt for recovery of lime.