Trinity River Basin Water Quality Management Plan: I. Degradation Rates of Advanced Treatment Effluents Anticipated in the Trinity River Basin, Texas. II. Oxygen Uptake of Organic Bottom Sludges from the Trinity River, Texas - Methods and Preliminary Results.

Abstract I: The aerobic degradation rates of advanced treated effluents were studied, and a kinetic model is proposed. Both the carbonaceous and nitrogenous deoxygenation rates followed pseudo first order, or monomolecular, kinetics, and the observed velocity constants were found to be lower than those reported in the literature for primary and secondary effluents. Mixing, temperature, and dilution effects on kinetic behavior were also studied. Given only the BOD5 and NH3N concentrations of an advanced treated effluent, an equation can be written to describe its rate of degradation.

Abstract II: The objective of this research was to determine the benthic oxygen demands of some sediment deposits in the Trinity River System in the Dallas-Fort Worth area. The reduced data will provide parameters to be used in modeling the river for dissolved oxygen and give an indication of the quality of the sediments. During the low flow periods, discharges from some of the major sewage treatement plants greatly affect the dissolved oxygen levels in the river. The dissolved oxygen in this area is often zero in some reaches of the river. This is partly due to the oxygen demand of the organic sediments in the river system. The samples were collected below the outfalls of the White Rock, Central and Riverside Sewage Treatment Plants. The oxygen demands were measured by galvanic oxygen cells. The sediments were in a quiescent state in some tests and completely suspended in other tests. The benthic demands of the quiescent samples at 20oC varied from 0.028 to 0.128 gm/hr-m2 and the higher values were of the same magnitude as found in the upper Houston Ship Channel at the time of the greatest BOD load to the channel, which was during 1965 through 1970. The demands of the suspended samples were much greater than the quiescent samples and were of the same order of magnitude as those from the Houston Ship Channel under the above heavily-loaded conditions.