Greywater treatment using a moving bed biofilm reactor at a university campus in Brazil

Abstract

Water reuse can contribute as an important approach and practice to the reduction of the pressures on water resources lowering the demand for potable water for purposes that do not require water's high quality. However the greywater reuse has been rarely applied in Brazil. Therefore, the main objective of this study was to evaluate a greywater collection and treatment system from lavatories, showers and washing machine aiming the non-potable reuse. The objectives were to characterize the quality and quantity of greywater from different sources, to monitor a pilot system for synthetic greywater treatment and to analyze the quality of the effluent after treatment. The pilot system implemented in a building at University of Sao Paulo allowed to segregate greywater collection and characterization. To evaluate the greywater production water flow meters were installed in the water inlet of each greywater source. The treatment system included a moving bed biofilm reactor and a settling tank at pilot scale. The evaluation of greywater treatment was conducted based on the monitoring of physicochemical and microbiological water quality parameters during the operation of the experimental system. Based on the results, amongst the three greywater sources, the water from showers had the highest E. coli concentration while the lavatories water had the highest total coliforms concentration. The removal efficiencies of BOD and COD were 59% e 70% respectively. The phosphorus removal during the experimental period was low. Nevertheless the water quality produced is viable to be applied for outdoor purposes - landscape and garden irrigation in household, commercial and institutional buildings and the results were satisfactory according to Brazilian standard. The treatment showed stability and reliability ensuring the potential for a safe reuse if appropriate operation and monitoring of the treatment system is performed.