Energy conservation in waste water treatment through value engineering

Overall, energy consumed by municipal wastewater treatment facilities is a relatively minor amount (less than one percent of the national total); however, energy required to treat sewage is increasing at a much faster rate than the national average. It is estimated that between 1977 and 1990, energy consumption by wastewater treatment facilities will increase by 109% while that for the nation will rise 44%. Design of treatment processes in the sanitary engineering field is energy intensive, based on the concept of abundant supply, low cost, and perpetual duration. The Federal Water Pollution Control Act amendments of 1972 (Public Law 92500) and the Clean Water Act of 1977 (Public Law 95-217) required a significant increase in the number of publicly owned wastewater treatment facilities and in the level of treatment provided. This mandate is backed by billions of dollars to achieve the goals quickly. The rush to design and construct the necessary facilities in order to meet the intent of the law has not overlooked the need for a cost-effective analysis of alternatives; however, energy is generally not a primary consideration. As a result, even though the facilities may be designed on an overall cost-effective basis, energy consumption per gallon ofmore » treated waste steadily rises. The commitment to improve water quality is being realized, but the consequences have not been adequately addressed.« less