GB847640A - Improvements relating to the treatment of industrial effluents - Google Patents

Abstract

847,640. Treating waste effluents. SIMONCARVES Ltd. July 25, 1958 [July 31, 1957], No. 24244/57. Class 111. Industrial waste effluents, e.g. coal carbonisation liquors, containing as toxic constituents (a) phenols and (b) thiosulphates, thiocyanates, cyanides and (c) ammonia (fixed or free) are treated with bacteria capable of destroying the toxic constituents while maintaining the pH and temperature of the effluents between limits at which the bacteria are active, and continuously introducing nutrients and oxygen for the bacteria, the bacteria for treating (a), (b) and (c) being respectively Vibrio Cyclosites, Vibrio O1, Pseudomonas S7 and Actinomycetaceae S2; Thiobacillus thiocyanoxidans, Thiobacillus S3, S4 and S5 ; and Nitrobacteraceae S6 to S11. The bacteria may be employed together in a single step treatment of effluents containing the toxic constituents using either percolating filters or sludge tanks inoculated with appropriate bacteria. Preferably the treatment is effected in stages with successive removal of (a), (b) and (c) in that order,, the toxic constituents of each group being reduced to a low concentration before subjecting the effluent to the next stage. Fig. 2 shows a plant for the treatment of coal carbonisation effluents. Effluent from a pipe 1 is passed through a hydraulic cyclone or settling tank 2 for removal of solid material, principally lime, is cooled by heat exchanger 3 and has its pH adjusted at 4 by addition of hydrochloric or sulphuric acid or waste pickle liquor from a tank 5. Nutrient solution for phenol destroying bacteria is added from tank 8. The liquor is pumped into activated sludge tanks 6 and 7 connected in series (as shown), or in parallel, where the concentration of phenols is substantially reduced by phenol-oxidising bacteria with which the tanks have been inoculated, air being introduced into tanks 6 and 7 by devices 24 and 25. The phenolfree liquor passes to a settling tank 9 where activated sludge separates at 11 and is recycled by pump 12. In the second stage, thiosulphates, thiocyanates, and cyanides are removed by passing liquor from 9, via heat exchanger 13, into an inoculated percolating filter 14. In the third stage, effluent now free of phenols, thiosulphates, thiocyanates, and cyanides are passed to sludge tanks 16 and 17 inoculated with ammonia-destroying bacteria. Nutrient solution from tank 19, calcium carbonate (to neutralize acids) from a hopper 20, and air from devices 26 and 27 are also added. Effluent is passed to a settling tank 18 from which it is discharged to waste through line 22 or recycled as dilution water through a pipe 23. One form of sludge tank for phenol and ammonia destruction consists, Fig. 3, of a turbine-type agitator 31 fitted with spaced beades 35 carried on a disc 36, the agitator operating in a tank 32 fitted with baffles. 33 Air is admitted through a sparger 34.