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Kinetic aspects of the treatment of phenolic wastes
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Waste Water Treatment
7. Activated sludge treatment gives satisfactory results at short aeration time,s, for partial treatment of the wastes. 8. Phenol in the waste water is completely removed by this method. 9. The sludge formed in the aeration tank has satisfactory settling characteristics--even for short aeration periods, and it is easily decomposable.
Kinetic aspects of the treatment of phenolic wastes. P. W. GRAHAM, L o n d o n , E n g l a n d It is now well established that strong phenolic wastes are amenable to biological oxidation, but the effects of the concentration of the waste on the dynamics of the process have not hithero received a great deal of attention. This paper described work on the kinetics of the treatment of such effluents derived from gas manufacture. Chromatographic and other analytical procedures have been used to follow the rate of oxidation of the phenolic material contained therein, and the information has been supplemented by bacterial counts. In high dilutions of the effluents, the kinetics of mixed cultures approximate to those of a simple continuous culture. Thus the percentage removal of oxidizable matter remains effectively constant at retention times down to a critical value below which the efficiencydecreases rapidly. This effect is not observed when higher concentrations of the effluents arc employed; under these conditions the efficiency of removal decreases progressively with decreasing retention time over a wide range of hydraulic and substrate loadings. Estimates of the specific growth of the organisms indicate that these effects are partially accounted for by dilution of non-phenolic inhibitory constituents of the effluents. Data are provided on the relationships between the weight of oxidizable matter removed, the yield of solids, and the uptake of dissolved oxygen. The advantages to the process of the recirculation of solids is demonstrated, and the influence of such recirculation and of the dilution effects on the design of treatment plants is discussed. The results are compared with those obtained in earlier work using full-scale modules of aeration tanks and packed towers.
Present-day aspects of effluent treatment and re-use in the U.S.S.R. metal-working industry. TH. L. BROOK-LEVrNSON, M i n s k , U.S.S.R. Modern metal-working plants consume great quantities of fresh water which have to be disposed of and this waste water should be taken into account in water resource conservation. Hitherto the use of either a closed or open circuit system was dictated only by constructional and maintenance costs. However, the need to consider water conservation alters the situation. Suspended matter, active chemical compounds (acid, alkali, salts), oil-products and other ingredients which pollute natural water and upset the oxygen conditions and change the pH-reaction, depress or alter the fauna and flora. To keep to the regulations concerning water pre~rvation policy would require a high degree of effluent purification (up to 95-99 per cent) that may not be practicable and would be expensive. The problem is best solved by preventing the discharge of effluents into rivers or at least achieving a big reduction. This may be achieved by re-use of effluents in closed-circuit systems that allow a reduction in the effluent to be purified and disposed of to rivers. At metal-working plants both mechanical and chemical methods of effluent treatment are used. When effluents in a closed-circuit system arc used the properties of water are affected not only by the influence of the manufacturing process but also by the reagent chemicals used in treatment. Thus effluent treatment by coagulation with FeSO4 and Al2(SO4)a results in progressive depletion of alkalinity, with the possibility of acidic reaction and corrosive properties. On the other hand application of alkali reagents, e.g. lime, may result in an increase pH and might result in conditions for deposition of scale. Thus, the introduction of a closed-circuit system with re-use of effluent may introduce the important
Waste Water Treatment
7. Activated sludge treatment gives satisfactory results at short aeration time,s, for partial treatment of the wastes. 8. Phenol in the waste water is completely removed by this method. 9. The sludge formed in the aeration tank has satisfactory settling characteristics--even for short aeration periods, and it is easily decomposable.
Kinetic aspects of the treatment of phenolic wastes. P. W. GRAHAM, L o n d o n , E n g l a n d It is now well established that strong phenolic wastes are amenable to biological oxidation, but the effects of the concentration of the waste on the dynamics of the process have not hithero received a great deal of attention. This paper described work on the kinetics of the treatment of such effluents derived from gas manufacture. Chromatographic and other analytical procedures have been used to follow the rate of oxidation of the phenolic material contained therein, and the information has been supplemented by bacterial counts. In high dilutions of the effluents, the kinetics of mixed cultures approximate to those of a simple continuous culture. Thus the percentage removal of oxidizable matter remains effectively constant at retention times down to a critical value below which the efficiencydecreases rapidly. This effect is not observed when higher concentrations of the effluents arc employed; under these conditions the efficiency of removal decreases progressively with decreasing retention time over a wide range of hydraulic and substrate loadings. Estimates of the specific growth of the organisms indicate that these effects are partially accounted for by dilution of non-phenolic inhibitory constituents of the effluents. Data are provided on the relationships between the weight of oxidizable matter removed, the yield of solids, and the uptake of dissolved oxygen. The advantages to the process of the recirculation of solids is demonstrated, and the influence of such recirculation and of the dilution effects on the design of treatment plants is discussed. The results are compared with those obtained in earlier work using full-scale modules of aeration tanks and packed towers.
Present-day aspects of effluent treatment and re-use in the U.S.S.R. metal-working industry. TH. L. BROOK-LEVrNSON, M i n s k , U.S.S.R. Modern metal-working plants consume great quantities of fresh water which have to be disposed of and this waste water should be taken into account in water resource conservation. Hitherto the use of either a closed or open circuit system was dictated only by constructional and maintenance costs. However, the need to consider water conservation alters the situation. Suspended matter, active chemical compounds (acid, alkali, salts), oil-products and other ingredients which pollute natural water and upset the oxygen conditions and change the pH-reaction, depress or alter the fauna and flora. To keep to the regulations concerning water pre~rvation policy would require a high degree of effluent purification (up to 95-99 per cent) that may not be practicable and would be expensive. The problem is best solved by preventing the discharge of effluents into rivers or at least achieving a big reduction. This may be achieved by re-use of effluents in closed-circuit systems that allow a reduction in the effluent to be purified and disposed of to rivers. At metal-working plants both mechanical and chemical methods of effluent treatment are used. When effluents in a closed-circuit system arc used the properties of water are affected not only by the influence of the manufacturing process but also by the reagent chemicals used in treatment. Thus effluent treatment by coagulation with FeSO4 and Al2(SO4)a results in progressive depletion of alkalinity, with the possibility of acidic reaction and corrosive properties. On the other hand application of alkali reagents, e.g. lime, may result in an increase pH and might result in conditions for deposition of scale. Thus, the introduction of a closed-circuit system with re-use of effluent may introduce the important