The operation of three storm standby tanks contiguous to an intercepting sewer which serves both combined sewers and sanitary sewers was investigated to determine the effectiveness of the tanks in improving the quality of the waste water prior to its discharge into the river. Based on influent and effluent sampling data collected during the study period, storm standby tank facilities reduce significantly concentration of the solids and B.O.D. in the waste water in storm runoff periods. The extent of reduction is dependent to a major degree on the detention time of flow passing through the tanks. Improvement of dissolved oxygen resulting from passage of waste water through the tanks is very substantial, especially during periods when the dissolved oxygen content of the influent is low.

To determine the feasibility of eutrophication control by controlling carbon, three major areas were studied: the steady state, in which the growth rates of algae at various constant, maintained dissolved carbon dioxide concentrations were determined; the non-equilibrium, where natural atmospheric replenishment was the sole carbon source; and algal growth with inorganic bicarbonate as the sole carbon source. In studying growth rates of Chlorella, Microcystis, and Anabaena with respect to carbon availability, it was found that algae can utilize dissolved concentrations of carbon dioxide much lower than those from atmospheric equilibria.

Of a number of methods available for phosphate removal from waste water, chemical precipitation (often called coagulation) using aluminum, ferric iron, ferrous iron and lime is considered to be the most economical. The objective of the present study has been two-fold: To evaluate the effects of pH and reactant concentration on the rate and efficiency of phosphate removal from synthetic and secondary effluent wastewaters and on the nature of the precipitates formed; and to compare the data on the Fe(II)-phosphate precipitation system with the available data for Fe(III)- and Al(III)-phosphate systems. Most of the experiments in the study were conducted on pure orthophosphate solutions and in the absence of dissolved oxygen. Only a limited number of tests were made of the use of ferrous iron for orthophosphate removal from wastewaters containing dissolved oxygen.

Predictions of the complex annual cycle of temperature changes in a lake or reservoir are necessary if proper water quality control is to be achieved. Many lakes and reservoirs exhibit horizontal homogeneity and thus a time-dependent, one-dimensional model describing the temperature variation in the vertical direction is adequate. A discretized mathematical model was developed based on the absorption and transmission of solar radiation, convection due to surface cooling and advection due to inflows and outflows. The model contains provision for simultaneous or intermittent withdrawal from multi-level outlets and time of travel for inflows within the reservoir.