Overview of Discharges from Pumping Stations and the Consequent Water Pollution Characteristics in Central Shanghai, China

Abstract

Discharges from pumping stations to rivers have become an important issue in central Shanghai. Based on the analysis of the contaminant concentrations and the volume of discharged water in central Shanghai over the past five years, this research has identified that the discharges from pumping stations to watercourse were composed of DWDs and WWDs. The total annual discharges were approximately 155 to 202 million cubic meters. The contaminant concentrations in the DWDs were close to those in the local domestic wastewater (DW), while the WWDs usually had higher concentrations of the contaminants than the local DW. In central Shanghai, the total contaminant discharges (2008 to 2012) from pumping stations were 72,900-95,700 t·a-1 for suspended solids (SS), 67,300-88,100 t·a-1 for chemical oxygen demand (COD), 20,200-27,100 t·a-1 for biochemical oxygen demand (BOD5), 2,000-3,000 t·a-1 for ammonia-nitrogen (NH3-N), 4,100-5,900 t·a-1 for total nitrogen (TN), and 800-1,300 t·a-1 for total phosphate (TP).