Investigation and assessment of wastewater outlets into main branch of Haihe River

The wastewater outlets at the main branch of the Haihe River were investigated and evaluated in 2007.The results showed that the discharged wastewater in the eight wastewater outlets at the main branch of the Haihe River all exceeded the pollution discharge standard of China.The types of discharged wastewater were industrial wastewater and mixed wastewater,and the main manifestations of pollution were organic pollution,eutrophication,and chemical industry pollution.The equivalent pollution load method was applied to the assessment of the wastewater outlets.The results showed that the Tianjian Pump Station,Tianjin Dagu Chemical Plant outlets,and Tianjian outlet gates were the main wastewater outlets to the main branch of Haihe River,and accounted for 27%,26%,and 17.4% of the wastewater,respectively.The total equivalent pollution load of eight wastewater outlets was 1.68×109t/a,which meant that 1.68×109tons of clear water were needed to dilute the wastewater in order to meet the discharge requirements.