Study On Emission Standards For Water Pollutant Of Vanadium Industry

Vanadium products industry is one of the high-polluting industries in non-ferrous metal. Since the beginning of the 21st century, China's vanadium industry has been developing rapidly, but the relative pollutant discharge standards can't match this raqpid development. Until now, the pollutant discharge standards of vanadium industry have not yet been introduced. Wastewater Discharge Standards and Water Pollutant Discharge Standards for Iron and Steel Industry are two pollutant discharge sandards that regulate vanadium industry today; however, the biggest problem is that the existing standards'regulations for the emission limit are not apropriate, and it also fails to cover certain needed regulative standards. Thus, being entrusted by the former State Environmental Protection Administration, SEPA Key Laboratory on Eco-industrial of Northeastern University begins to constitute the Non-ferrous Metals Industry Pollutant Discharge Standards for vanadium and its compounds. Under this background, this paper investigates the related water pollutant discharge standards of vanadium industry.There are two methods in the setting of emission limits (the core contents of emission standards):First, it may be set based on pollution control technology; Second, it may be set based on human health and environmental risks. The first one is the commonly used methods at home and abroad, while the second one is only experimented in developed countries as the first one's supplementation. In china, there haven't been any reports yet about the second method. First, the paper sets the pollutant discharge limits using the first method. On this basis, it establishes the water pollutant discharge model of vanadium industry. Then, the second method is adopted to set the the chemical oxygen demand (COD) and NH3-N value in the water pollution emission limits. Finally, a comparative analysis are conducted between the the values of COD and NH3-N got by the two methods.(1) Based on pollution control technology, the identified limits of water pollution emission standards in vanadium industry are:The respective emission limit values for the existing enterprises, new enterprises, and advanced control technology are, COD:100mg/L,80 mg/L,50 mg/L; NH3-N:40 mg/L, 25mg/L,15mg/L;pH:6～9,6～9,6～9;SS:70mg/L,50mg/L,30mg/L;TN:45mg /L,30mg/L,20mg/L;TP:1.5mg/L,1.0mg/L,0.5mg/L;S2-:1.0mg/L,1.0mg/L 1.0mg/L;Cl-:600mg/L,400mg/L,300mg/L;V:2.0mg/L,1.0mg/L,1.0mg/L; Cr6+:0.5mg/L,0.5mg/L,0.5mg/L;TCr:1.5mg/L,1.5mg/L,1.5mg/L;TCd:0.1mg/ L,0.1mg/L,0.1mg/L;The water emission limits for products unit are:50t/t,30t/t,10t/t.(2)The emission limits values based on human health and enviroment are,COD:60 mg/L;NH3-N:26mg/L.The result of the comparitive analysis indicates that the emission limits values based on human health and environmental risks are stricter than that based on pollution control technology.Therefore,China should combine the two methods of emission limits setting,and make stricter emission standards.Thus,it can gradually meet enviromental protection requirements.