Evaluation Method of Best Available Technologies for Rural Domestic Wastewater Treatment and Case Study

A comprehensive evaluation method was developed for screening rural domestic wastewater treatment technologies, taking per unit occupied area as the restricted factor, and adopting the cost-benefit analysis for the core factors and analytic hierarchy process (AHP) with grey relational degree method for secondary factors. The development process of mathematical models was provided with a case study. Six rural domestic sewage treatment technologies, including A/O, A²/O, hydrolytic acidification-biological contact oxidation process, anaerobic-constructed wetland (CW), anaerobic-ecological gully, and anaerobic-oxidation pond, were screened out as typical technologies based on literature review, on-site survey and questionnaire. The three single factors evaluations were performed individually and then the comprehensive evaluation conducted. The results of single factor evaluation showed that the hydrolytic acidification-biological contact oxidation process was the best available technology (BAT) in restricted factors evaluation and secondary factors evaluation, while the anaerobic-CW was the BAT in core factors evaluation. The results of comprehensive evaluation showed that the hydrolytic acidification-biological contact oxidation process was the BAT for rural domestic wastewater in the area in lack of land, and that the anaerobic-constructed wetland was the BAT in the area with more lands.