Full-scale integrated skid-mounted plug flow photocatalytic reactor: Treatment of hospital wastewater

Abstract

A full scale treatment of hospital wastewater (60 m3/day), was newly developed, combining many processes including activated sludge, coagulation-flocculation, and skid-mounted photocatalysis. The tested raw hospital wastewater had the following characteristics: biochemical oxygen demand (BOD): 250–400 mg/L, chemical oxygen demand (COD): 800–1000 mg/L, ammonia nitrogen (NH3-N): 70–100 mg/L, total phosphorus (TP): 3.0–5.0 mg/L, suspended solids (SS): 200–300 mg/L and fecal coliform (FC): 9.2 × 104–1 × 105 MON/L. During more than 3 years the in-situ operation of the average removal efficiency of COD was 90–95% with an effluent value in the range of 35–48 mg/L. The average removal efficiency of BOD, FC, TP, NH3-N, SS, color, and turbidity was in the range of 85–90%, 95–97%, 75–80%, 50–55%, 89–92%, and 95–97%, respectively. The overall operating cost was determined as 3.5 RMB /m3. This innovative technology was evaluated at a full-scale plant, demonstrating that its application was feasible and addressed many environmental concerns. This reactor has the following advantages: modular design, low infrastructure investment and simple operation. More importantly, this could be one of the first commercial photocatalytic reactors.