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活性染料具有颜色鲜艳、均染性好、应用简便、染色牢度高、价格低廉等特点,是我国染料工业中第2大类染料品种[1]。对位脂(对氨基苯基-ß-羟乙基砜硫酸)含有重氮化组分的氨基和能发生化学反应生成染料-纤维共价键的反应性基团,能大大提高染料的利用率,所以成为活性染料最重要的中间体,市场需求更为庞大[1-2]。目前国内对位酯产量约为1.6×105~1.8×105 t·a−1。但是生产1 t对位脂要产生30 t的废水,同时这些废水COD浓度高,可生化性差[3],因此,高效处理对位酯生产废水具有很重要的实际意义。已有研究[3-4]表明,采用Fenton-水解酸化-好氧组合工艺和铁碳微电解-Fenton-光催化联合工艺,能去除大部分的COD;但是Fenton反应作为预处理,过氧化氢和酸碱试剂消耗成本太高。在工程实践中,处理高浓度难降解有机废水时,使用厌氧工艺作为前端处理工艺,具有沼气可回收利用、可提高废水的生化性及可降低运行成本等特点。由于对位脂生产废水含有大量的硫酸盐(COD/
$ {\rm{SO}}_4^{2 - } $ 为3.58),同时对位酯属于有机硫化合物,其含有磺酰基和硫酸盐基团,容易水解(结构式见图1),因此,也间接地增加了进水硫酸盐的负荷,使COD/$ {\rm{TSO}}_4^{2 - } $ (总硫酸盐)降至2.4。有研究[5]表明,在进水COD/$ {\rm{SO}}_4^{2 - } $ >3.3(碳硫比>10)时,产甲烷菌不会受硫酸盐被还原时所产生硫化物的抑制,这也是厌氧工艺在工程应用的基本条件。已有研究[6]采用单一的厌氧复合床处理该废水,只能运行到COD至15 000 mg·L−1,对应COD容积负荷为5.0 g·(L·d)−1,如进一步提高COD至20 000 mg·L−1,产甲烷和反硝化能力完全丧失。本研究利用微电场-零价铁,来提高UBF处理高硫酸盐和高有机硫废水中的运行负荷及同步产甲烷和反硝化的能力。结果表明,同步产甲烷反硝化过程具有一定的经济可行性,能为后续的硝态氮去除工艺减轻负担。
微电场-零价铁-UBF提高有机硫对位酯生产废水同步产甲烷反硝化效能
Enhanced SMD process in treating organic sulfur compounds and para-ester manufacturing wastewater by micro-electric field-ZVI-UBF
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摘要: 有机硫化合物对位酯生产废水具有COD高、含硫酸盐和有机硫高以及碳硫比低的特点,针对单一厌氧反应器在处理废水时只能在较低COD容积负荷(OLR)下运行的问题,在提高有机硫对位脂生产废水产甲烷反硝化效能的基础上,采用微电场-零价铁联合方式处理该类废水。实验结果表明:OLR(以COD计)为6.67 g·(L·d)−1,进水COD为20 000 mg·L−1时,复合床的COD去除率为70%,产甲烷率为1.41 L·(L·d)−1,反硝化率为87%,对位脂降解率为74%;在COD/
$ {\rm{TSO}}_4^{2 - } $ (总硫酸盐)为1.57时,COD去除率、产甲烷率和反硝化率可分别能稳定在60%、1.18 L·(L·d)−1和79%;在COD/$ {\rm{TSO}}_4^{2 - } $ 为0.88时,产甲烷菌受到中等程度的抑制;当COD/$ {\rm{TSO}}_4^{2 - } $ 恢复为1.57时,厌氧系统在7 d后恢复,说明联合系统有很强的恢复能力。综合上述结果,与单一的UBF处理相比,采用微电场-零价铁能显著提高UBF的运行负荷和同步产甲烷反硝化能力,同时也能使反应器承受更低的碳硫比。-
关键词:
- 微电场-零价铁-UBF /
- 有机硫化合物 /
- 对位脂生产废水 /
- COD/$ {\rm{TSO}}_4^{2 - } $ /
- 同步产甲烷反硝化
Abstract: Organic sulfur(s) compounds and para-ester manufacturing wastewater was characterized as high COD, rich sulfate and organic S compounds and low C/S ratio. Single anaerobic reactor treating this kind of wastewater can only run at low COD loading rate (OLR), then the micro-electric field - zero-valent-iron (ZVI) joint system was used to treat it based on the enhancing effect of methanogenesis and denitrification from organic S compounds and para-ester manufacturing wastewater. The experimental result indicated that the compound bed could remove 70% of COD, achieve 1.41 L·(L·d)−1 of methane production rate, 87% of denitrification efficiency and 74% para-ester degradation efficiency at COD organic load rating (OLR) up to 6.67 g·(L·d)−1 and influent COD of 20 000 mg·L−1. At COD/$ {\rm{TSO}}_4^{2 - } $ (total sulfate) of 1.57, COD removal efficiency, methane production rate and denitrification efficiency could be stabilized at 60%, 1.18 L·(L·d)−1 and 79%, respectively. At COD/$ {\rm{TSO}}_4^{2 - } $ of 0.88, a moderate inhibition of methanogenesis occurred, while the anaerobic system could recover after seven days when COD/$ {\rm{TSO}}_4^{2 - } $ was set back to 1.57 again, indicating the resilience of the joint system. This study revealed that compared with single UBF treatment, the combination micro-electric field-zero-valent-iron (ZVI) with UBF not only resulted in the significant increase of operated OLR and the ability of simultaneous methanogeneis and denitrification (SMD) of the joint system, but also tolerance to lower C/S ratio. -
表 1 微电场-零价铁-UFB各个运行阶段的废水成分及COD容积负荷
Table 1. Water quality parameters and COD volume load of wastewater inmicro-electric field-ZVI-UBF at different stages
阶段 时间/d COD/
(mg·L−1)对位酯/
(mg·L−1)硫酸盐/
(mg·L−1)有机硫(以 $ {\rm{SO}}_4^{2 - } $ 计)/
(mg·L−1)硝态氮/
(mg·L−1)OLR/
(g·(L·d)−1)Ⅰ 1~30 500 100 223 68.4 1.1 0.167 Ⅰ 31~45 2 000 400 558 273.6 4.4 0.668 Ⅰ 46~60 5 000 1 000 1 395 684 11 1.67 Ⅰ 61~75 10 000 2 000 2 790 1 368 22 3.34 Ⅰ 76~90 15 000 3 000 4 185 2 052 33 5.01 Ⅰ 91~105 20 000 4 000 5 580 2 736 44 6.68 Ⅱ 106~125 20 000 4 000 10 000 2 736 44 5.01 Ⅲ 126~140 20 000 4 000 20 000 2 736 44 5.01 Ⅳ 141~160 20 000 4 000 10 000 2 736 44 5.01 -
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