Treatment of high nitrogen wastewater by coagulation－iron carbon microelectrolysis－sodium hypochlorite oxidation process; [混 凝 — 铁 碳 微 电 解 — 次 氯 酸 钠 氧 化 处 理 高 氮 废 水]

作者：Huang Lei; Liu Yefang; Le Xiaonan; Huang Ruimin^*

来源：工业水处理, 2022, 42(4): 125-131.

DOI：10.19965/j.cnki.iwt.2021-1039

• coagulation
• iron carbon microelectrolysis
• printing wastewater
• sodium hypochlorite

In order to solve the problem of high nitrogen load caused by large fluctuation of wastewater in a printing and dyeing industrial park，a combined coagulation－iron carbon microelectrolysis－sodium hypochlorite oxidation process was used to treat the high nitrogen wastewater. The experimental results showed that the COD removal rate in coagulation stage reached 83.12% under the conditions of no adjustment of initial pH，ferrous sulfate and poly-acrylamide dosage of 400 and 15 mg/L，respectively. Under the conditions of initial pH of 4，iron-carbon mass ratio of 1∶1，iron dosage of 60 g/L，gas-water ratio of 5∶1 and HRT of 120 min，iron-carbon microelectrolysis was applied to the coagulation effluent. The effluent pH increased to 6.91，and the removal rates of COD and NO3--N were 50.26% and 53.66%，respectively，with NH4+-N as the main reduction product of NO3--N. The microelectrolysis effluent was treated with sodium hypochlorite. Under the conditions of no adjustment of initial pH，sodium hypochlorite to total Kjeldahl nitrogen mass ratio of 8.5∶1 and reaction time of 30 min，the removal rates of TN and NH4+-N were 88.56% and 97.75%，respectively. After intermittent treatment of combined process，the effluent COD≤55 mg/L，TN≤14 mg/L and NH4+-N≤1 mg/L，met the direct discharge requirements in Table 2 of the Discharge standards of water pollutants for dyeing and finishing of textile industry（GB 4287—2012）. After calculating，the cost of chemical agent of the process is 5.09 Yuan per ton. ? 2022 Editorial Office of Industrial Water Treatment, CNOOC Tianjin Chemical Research and Design Institute Co., Ltd.

• 单位
  华南理工大学