The development of process kinetics for a waste treatment system utilizing filamentous microorganisms

Abstract

The capabilities of a biological waste treatment system designed to utilize filamentous microorganisms were defined in this study. Various chemical and physical tests such as pH, suspended solids, COD, BOD, sludge production, and oxygen utilization were used to determine the effects of parameters like flow rate, support media area, organic loading, pH, and the BOD-to-nitrogen ratio.

Findings of the study indicated that the removal rate, suspended solids concentration in the effluent, and percent COD remaining in the final growth cell of the growth chamber increase as the dilution rate or flow rate increase.

The study also showed that an organic waste can be effectively treated by a filamentous system over an influent pH range of 2.65 to 7.45 with an oxygen requirement similar to that found in other biological treatment systems. An increase in organic loading caused an increase in the suspended solids of the effluent with a decrease in COD removal efficiency. The removal rate was found to be directly proportional in influent COD concentration from a concentration of approximately zero to a concentration equal to 1200 milligrams per liter.

A nitrogen deficient waste at both neutral and acid pH's was treated effectively by this system. For a pH range of 2.65 to 2.85, the critical BOD:N ratio was found to be greater than 45:1. A BOD:N ratio in excess of 90:1 was found to be critical for a waste with a pH range of 6. 6 to 7. 45.

Recirculation of biological solids was not needed to retain sufficient culture in the growth chamber for efficient treatment of the waste. Sludge production values were found to be close to values for the activated sludge process treating organic wastes. The average value for "a" on a COD and total solids basis was found to equal 0.48 for most of the conditions studied. However, a tendency for sludge to build up for a period of time and then slough off was noted. The average value for "a" decreased significantly to 0.18 when the pH was lowered to a pH of 2.60 and increased significantly for BOD:N ratios above the critical ratios.