Microbial Treatment and Utilization of Waste

Abstract

Waste treatment and utilization presents a particular challenge to the biotechnologist. Wastes are highly diversified and have time variable compositions. Waste treatment processes are frequently run in a nonaseptic environment and with mixed cultures of microorganisms. The challenge is to stabilize the system and design a process that will assure the needed degree of reliability and product specification. The products of a waste treatment process can be a liquid or gaseous fuel, an animal or human feed or food, chemicals, fertilizer or drinkable water. Every waste is unique in character and amount with each location. Consequently, there is a unique optimal solution for the handling of each waste which may depend not only on the economics, but upon local needs and attitudes. It is becoming clear that future populations must view wastes not as a troublesome problem, but as a recycleable resource in which the nutrients or the chemicals from that waste are economically returned to the community. This paper will briefly review the various waste treatment and utilization alternatives and then focus in on the treatment of human sewage. It will specifically examine the problems of optimal removal of BOD, nitrates and nitrites and phosphate plus the utilization of the microbial sludge and other products derived from the treatment processes.