A Study of Possible Toxic Effects of Chili- Processing Waste Water on Activated Sludge Process

An investigation of the possible effects of chili-processing waste water on microbial populations instrumental in biological waste treatment was conducted. Batch reactors were used to conduct experiments which compared the treatability of chili-processing waste waters to the treatability of municipal sewage. Experiments were also conducted to determine the effect of acclimation of biological solids on treatability. Using low initial solids concentrations in some experiments, values of constants in Monod kinetics were determined for the chili-processing waste waters.

It was concluded that chili-processing waste waters are amenable to biological treatment and exhibit no gross toxic effects on the biological solids. However, the soluble chemical oxygen demand (COD) is removed at rates slower than the rate at which the soluble COD in municipal sewage is removed. Also, the chili-processing waste waters have a higher level of refractory COD than does the municipal sewage. It was demonstrated that the difference in rates of removal of soluble COD from chili-processing wastes and from municipal sewage was due to acclimation of biological solids to a particular substrate.

Monod-predicted rate constants differed significantly from experimentally-determined ones. This was concluded to result from an inability to precisely and accurately determine viable initial organism concentration from suspended solids measurements.

Project No. 3109-214, 1345629