After wastewater is pretreated by iron scrap method, the ratio of COD/N lowers, nitritation process will be carried out much earlier, which is beneficial to shortening the total aeration time.

• 焦化废水经铁碳电池预处理后，COD/N比值降低，亚硝化反应可以较早进行，有利于缩短系统的总曝气时间。