The underground industry of wastewater adulteration: how to trick legal testing with COD removers

Adulteration is an illegal practice often committed in food and cosmetic industries, yet rarely environmental regulation compliance. The Chinese Ministry of Ecology Environment recently issued a law prohibiting any intentional use ‘interfering agents’ during wastewater compliance testing. For the first time, such practices are brought to public attention, though they have been barely discussed previously scientific literature. fraudulent method involves addition into sodium chlorate-based compound, named 'COD remover,' which artificially decreases chemical oxygen demand (COD) measured legal testing using dichromate method. Such can decrease COD from 214 mg/L below 100 mg/L. removers designed work under conditions, do not effectively purify wastewater. has created underground industry, where users anonymously purchase those products 25-kg packages all major domestic online retailers China. A notable case was publicized after new legislation, 131 tons remover had used municipal treatment plant. Nonetheless, very little known about other possible cases China elsewhere, whether sole target instance, nitrites could be as interfering agents iodometric for measuring dissolved water There also reports adulteration monitoring gas emissions. Since targeted based on knowledge reactions mechanisms methods, there need develop more robust adulteration-proof methods