Energy Conservation And Consumption Reduction In Wastewater Treatment System Based On Cleaner Production Theory

Energy and resources used in wastewater treatment systems (WTSs) account for acertain proportion of total amount of consumption in China. However, many technicaldifficulties remain in terms of engineering and management for energy and resourcesconservation in WTS, particularly, the lack of sustainable management systems andfeasible engineering measures. Cleaner production theory, as a new strategy, provides asystemic solution for WTS to save energy and to lower resource consumption.Through field investigation, experiment, and practical demonstrations, this study isdevoted towards the analysis of energy conservation and consumption reduction inWTSs based on cleaner production theory, especially the sound evaluation indicators,the technologies for efficient use of influent carbon source, and aeration control. Anadaptive management approach is then applied to promote sustainable implementationof cleaner production in WTSs.Comprehensive reviews were conducted regarding the development of sewagetreatment systems and cleaner production. The properties of the production process andthe significance of cleaner production for WTS were also investigated. A systemicframework for energy and resources conservation in WTSs in the context of evaluationsystems, engineering technologies, and management programs was developed. On thebasis of the review above and through field studies of11municipal WTSs, this studyestablishes a model that directly reflects energy consumption and operating cost for thetotal emission load reduction of COD, NH4+-N, TN, and TP. The model results showthat the key technical measure for Gaobeidian WTS is an efficient use of influent carbonsource to reduce consumption, whereas the Qinghe WTS utilizes aeration systemoptimization control to save energy.The pilot plant testing and demonstration in the Gaobeidian WTS showed that theactivated primary sedimentation tank possesses both utilization of influent carbonsource and removal of influent pollutants. When the conventional primarysedimentation tank and activated primary sedimentation tank was used in combinationaccording to the actual situation, biological nutrient removal without carbon source andenergy conservation was achieved simultaneously. In the demonstration of the QinghePhase II WTS, adjustable weir was used to regulate water balance of every unit, whereas nitrification aeration control was used to allocate the airflow distribution in theaerobic zone to reduce aeration system pressure and excessive aeration. Finally thisstudy establishes an adaptive framework for the sustainable implementation of cleanerproduction for the Gaobeidian and Qinghe WTSs, thereby ensuring that the proposedtechnical measures for energy conservation and consumption reduction are sustainable.