Selection of sewage treatment systems based on Multicriteria Analysis - Evaluation of different preference structures

ABSTRACT The main perspective of this work is the selection of sewage treatment systems for the Pardo river hydrographic basin, a watercourse located in the southern region of the state of Espírito Santo, Brazil, by using a Multicriteria Analysis, considering two different preference structures. Minimum Biochemical Oxygen Demand removal efficiencies were used as pre-selection criteria. The treatment systems hierarchy involved a set of environmental, technological, operational and social criteria. To conduct the Multicriteria Analysis, the ELECTRE II method was used. The results indicated that the imposition of standards for effluents led to the selection of activated sludge treatment systems variations, mainly for denser population centers. The incorporation of the watercourses self-purification capacities reduced the treatment effort within the basin, leading, for different urban centers, to the selection of stabilization ponds or Upflow Anaerobic Sludge Blanket reactors treatment systems variations. The preference structures analyzed, however, led to the selection of different treatment systems for different urban centers and sewage discharge conditions, with more pronounced variations for localities presenting smaller populations.

摘要 本研究的核心视角为：采用多准则分析方法，针对位于巴西圣埃斯皮里图州南部的帕尔多河（Pardo river）水文流域，选取适配的污水处理系统，研究中考虑了两种不同的偏好结构。以最低生化需氧量（Biochemical Oxygen Demand）去除效率作为预筛选准则。污水处理系统的层级评价体系涵盖环境、技术、运行及社会四类准则。本次多准则分析采用ELECTRE II法。研究结果表明：污水排放标准的实施会导向活性污泥处理系统变体的选取，该情况在人口更为密集的城镇中心尤为突出。纳入河流水体自净化能力的考量后，流域内所需的处理负荷有所降低，进而针对不同城镇中心，可选取稳定塘或上流式厌氧污泥床（Upflow Anaerobic Sludge Blanket）反应器处理系统变体。然而，所分析的两类偏好结构会针对不同城镇中心及污水排放条件选取差异化的处理系统，在人口规模较小的区域，这种系统选择的差异更为显著。