Impacts of waste water from main factories on water quality of Tolich river, Hanoi

Abstract

Waste water from industrial sites amount to one third of total waste water discharged into Tolich river and may have serious effects on the river water quality. With the total amount of waste water of factories (Hanoi beer alcohol and beverage joint stock corporation - HABECO, Trang An JSC and Thuong Dinh industrial park) of 45000 m3/day, these factories account for more than a half of total industrial waste water released into Tolich river. The analytic results of waste water from the main factories (HABECO, Trang An JSC, Thuong Dinh industrial park, Hanoi Soap JSC, Sao Vang Rubber JSC, Tool No.1 JSC) show that the parameters of TSS, BOD5, COD, total of nitrogen, total of phosphorus are higher than the Vietnamese standards for industrial waste water QCVN 24:2009/MONRE, column B, because the factory has an effective wastewater treatment system. The heavy metals parameters of waste water from all factories without treatment: HABECO releases 1974 tons of BOD, 766 tons of TSS, 8,4 tons of phosphorus and 52,5 tons of nitrogen annually; Trang An JSC releases 64,8 tons of BOD, 48,6 tons of TSS, 0,6 tons of phosphorus, 1,6 ton of nitrogen and 25 tons of oil and grease; HASO releases 30 tons of BOD, 33 tons of TSS and 5 tons of oil and grease. Thus, if the waste water is not treated, it can lead to a very seriously pollution of Tolich river.