Control of Pollution Load from Industrial Wastewaters and Their Appropriate Treatments

Abstract

Concept and procedures to minimize pollutants discharge from industries into the water environment are discussed in this paper, as well as the improvement of performance and energy conservation in wastewater treatments. The first priority should be the reduction or elimination of wastewater discharge from the production process before considering the treatments. Material balance in the production process can clarify the composition of wastewater, and thus the source of pollutants discharge. A flowchart to characterize the wastewater in terms of coagulation, biological and chemical degradation, and activated carbon adsorption of pollutants in the wastewater is introduced and discussed. Microbial quinone profile is successfully introduced to clarify the acclimatization of microbes to refractory chemicals such as dimethyl sulfoxide (DMSO). Various wastewater treatments are categorized for organic wastewater treatment on the basis of biodegradability of organic pollutants defined as BOD and the theoretical oxygen demand (ThOD) ratio and their molecular size. Major biological treatment processes are characterized from viewpoints of the power economy, which is defined as the mass of BOD removed per unit energy consumption, and the rate of BOD removal per unit floor area of each process. The effect of air diffuser arrangement on the energy consumption for oxygen supply is quantitatively evaluated and discussed because the aeration takes major part of the total energy consumption in the activated sludge process.