School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; Guangdong Provincial Engineering and Technology Research Centre for Environmental Risk Prevention and Emergency Disposal, Guangzhou 510006, China.
School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
J Environ Sci (China). 2018 Feb;64:306-316. doi: 10.1016/j.jes.2017.07.003. Epub 2017 Jul 12.
Coking wastewater (CW) contains toxic and macromolecular substances that inhibit biological treatment. The refractory compounds remaining in biologically treated coking wastewater (BTCW) provide chemical oxygen demand (COD) and color levels that make it unacceptable for reuse or disposal. Gas-phase pulsed corona discharge (PCD) utilizing mostly hydroxyl radicals and ozone as oxidants was applied to both raw coking wastewater (RCW) and BTCW wastewater as a supplemental treatment. The energy efficiency of COD, phenol, thiocyanate and cyanide degradation by PCD was the subject of the research. The cost-effective removal of intermediate oxidation products with addition of lime was also studied. The energy efficiency of oxidation was inversely proportional to the pulse repetition frequency: lower frequency allows more effective utilization of ozone at longer treatment times. Oxidative treatment of RCW showed the removal of phenol and thiocyanate at 800 pulses per second from 611 to 227mg/L and from 348 to 86mg/L, respectively, at 42kWh/m delivered energy, with substantial improvement in the BOD/COD ratio (from 0.14 to 0.43). The COD and color of BTCW were removed by 30% and 93%, respectively, at 20kWh/m, showing energy efficiency for the PCD treatment exceeding that of conventional ozonation by a factor of 3-4. Application of lime appeared to be an effective supplement to the PCD treatment of RCW, degrading COD by about 28% at an energy input of 28kWh/m and the lime dose of 3.0kg/m. The improvement of RCW treatability is attributed to the degradation of toxic substances and fragmentation of macromolecular compounds.
焦化废水（CW）含有有毒和高分子物质，会抑制生物处理。经生物处理后的焦化废水中（BTCW）残留的难降解化合物提供了化学需氧量（COD）和色度，使其无法重复使用或处置。利用羟基自由基和臭氧作为氧化剂的气相脉冲电晕放电（PCD）被应用于原焦化废水（RCW）和 BTCW 废水作为补充处理。研究的主题是 PCD 对 COD、苯酚、硫氰酸盐和氰化物降解的能效。还研究了添加石灰有效去除中间氧化产物的成本效益。氧化的能效与脉冲重复频率成反比：较低的频率允许在较长的处理时间内更有效地利用臭氧。RCW 的氧化处理在 42kWh/m 传递能量下，将苯酚和硫氰酸盐分别从 611 降至 227mg/L 和从 348 降至 86mg/L，脉冲重复频率为 800 次/秒，BOD/COD 比（从 0.14 提高到 0.43）有了很大的提高。BTCW 的 COD 和色度分别去除了 30%和 93%，在 20kWh/m 的能量输入下，PCD 处理的能效超过传统臭氧氧化的 3-4 倍。石灰的应用似乎是 RCW 的 PCD 处理的有效补充，在 28kWh/m 的能量输入和 3.0kg/m 的石灰剂量下，COD 降解约 28%。RCW 可处理性的提高归因于有毒物质的降解和高分子化合物的碎片化。
