Rainwater Treatment and Reuse in Harbor Yard

Abstract

Coagulation-sedimentation and Filtration by fibre-ball were applied to treat rainwater collected in Harbor Yard. The optimum parameters of coagulation-sedimentation process were determined through experiment. The dosage of Polymeric aluminum chloride (PAC) was 35 mg/L, settling time was 30min, the mixtures were stirred for 1min under the rotational speed of 200~400 r/min, then stirred for 10 min at 90~120 r/min, and10 min at 40~60 r/min. While the optimum parameters of filtration by fibre-ball were also found, including filter speed of 15-30 m/h, Filtration clcle 60-100h, Pollutant Capacity of 9.5-18.3 kg/m3, combine washing by fresh water (flow of 25L/ (m2∙s)) and gas (flow of 40 L/ (m2∙s)) with washing time of 20min. All those parameters were utilized in a rainwater treatment project of coal container yard in Tianjin Harbor. The effluent quality could satisfy the demand of Water quality standard for urban miscellaneous water consumption, and the clear water after treatment was used for spraying coal and removing dust.