Wastewater treatment performance of a vermifilter enhancement by a converter slag-coal cinder filter

The study aimed at investigating rural domestic wastewater treatment performance through vermifilter enhancement by a converter slag-coal cinder filter. The research was carried out by column experiments in a lab scale. Results showed the average removal rate of TCOD, BOD, ammonia nitrogen (NH4+-N) and phosphorus removal by the system were 78.0%, 98.4%, 90.3%, 62.4%, respectively at a hydraulic loading rate of 4 m3 m−2 day−1. Vermifiltration was effective for insoluble organic matter and suspended solid removal, and the converter slag-coal cinder filter played an important role in phosphorus removal. The molecular weight of particles in the influent and effluents from every unit of the system were distributed in a wide range between 0.1 kDa and 10,000 kDa with predominance of values between 10 kDa and 300 kDa; the major portion of soluble material are high MW compounds. In addition, the optimal design parameters for vermifiltration and converter slag and coal cinder filters, respectively, were studied in the experiments.