THE EFFECTS OF ADVANCED WASTEWATER TREATMENT ON THE WEST FORK, WHITE RIVER (WATER QUALITY MODELING, INDIANA)
Abstract
The West Fork, White River has had a long history of poor water quality, with severe violations of established water quality criteria. A study of the White River was undertaken in order to evaluate the effects of Advanced Wastewater Treatment (AWT) implementation at the City of Indianapolis' two wastewater treatment plants. The major components of AWT included oxygen activated sludge with nitrification, multi-media filtration and ozonation. This investigation of river conditions before and after AWT addition included water quality surveys, dissolved oxygen (DO) profile analysis and nitrifier enumerations, conducted during the summer and fall of 1982 and 1983. Water quality survey results indicated that a shift in the pattern of river nitrification occurred after AWT addition, with substantial decreases in NH(,3)-N concentrations and increases in NO(,3)-N concentrations. DO and chlorophyll a levels were also significantly higher in 1983 than in 1982. Although an increase in biodegradability was observed for Indianapolis' treated effluent as a result of ozonation, a change in the White River could not be shown. With AWT addition, the ratio of photosynthesis to total community respiration increased, indicating a heterotrophic to autotrophic ecosystem shift. Simulation of White River DO profiles with the DOSAG-I model suggested that a change in nitrification kinetics (zero to first order) occurred from 1982 to 1983 as a result of decreased NH(,3)-N levels. DO profile analysis also indicated that benthic demand, which represented the most significant DO sink for the White River was substantially reduced in 1983. Enumeration of suspended and periphyton associated Nitrosomonas and Nitrobacter revealed that nitrifier populations decreased from 1982 to 1983. Because this drop in nitrifying bacteria numbers was greater than the decrease observed in nitrification rates, it was concluded that nitrifiers remaining in 1983 exhibited more nitrifying activity than those found in 1982. As a result of overall water quality improvements concomitant with AWT addition, established water quality criterium for the White River were generally met in the 1983 sampling season.
Degree
Ph.D.
Subject Area
Sanitation
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