Because coke sewage contains lots of hard-biodegraded and toxicant substances, it is considered one of the industrial waste water which is difficult to purify.
焦化废水由于含有大量的难生物降解与有毒物质，因而成为公认难处理工业废水之一。
2
Because coke sewage contains lots of hard-biodegraded and toxicant substances, It is considered to be one of the most difficult industrial wastewater to purify.