Effect of Co-substrate on Degradation of Benzothiazole in MEC

Due to its persistence and bio-toxicity,benzothiazole(BTH) cannot be biodegraded efficiently.Recent work has shown that removal rates of biorefractory organics can be enhanced by the addition of cosubstrates.In this work,ethanol,acetate,propionate and butyrate were added as co-substrates in order to promote the degradation of BTH in microbial electrolysis cell(MEC).By probing the changes in degradation rates of BTH in the presence of different co-substrates,it was observed that all the four co-substrates can enhance the BTH degradation in MEC,both the efficiency(EBTH) and the rate(RBTH).It was also found that acetate is more effective than others,which made the degradation efficiency of BTH up to 90% with acetate-C at350 mg/L(measuring by the carbon content of co-substrate,the same below),within 6 h and the degradation rate of BTH arrived 0.001 2/(mg·h).The microbacteria in MEC have also been influenced by different cosubstrates.This metabolism of the co-substrates enables the microbacteria on anode to generate ATP and thus grow to ensure the microbacteria activity.Therefore,this work showed that the addition of co-substrates such as acetate can be a novel and efficient approach for improving the elimination of BTH from wastewaters by MEC system.     

共基质代谢对难生物降解有机物的作用研究

难降解有机物容易在环境中不断积累,而且大多数有机物对人体和其他动植物产生危害.这种有机物处理比较困难,共基质代谢作用可以提高微生物的生化活性,从而提高降解有机物的能力.文中介绍了共基质代谢作用对难降解有机物进行生物处理时的作用机理、特点、影响因素及研究现状,以及共基质代谢作用在以后生物处理过程中的发展前景.     

共基质促进生物电催化还原硝基苯研究

为提高生物催化电解系统(BCES)定向还原硝基苯的能力,促进难降解有机物的快速脱毒和进一步生物转化,采用葡萄糖作为共基质,探讨其质量浓度对于生物阴极催化性能和硝基苯还原效率的影响.结果表明,共基质能够作为额外电子供体加速硝基苯向苯胺的定向转化,同时提高了生物阴极催化硝基苯还原的活性,表现为硝基苯还原峰电位正移70 mY.为避免过度增加废水中的COD,共基质的引入量控制在200 mg·L-1较为适宜,此时苯胺的生成率在各外加电压条件下(0.15～0.5 V)均超过97％,硝基苯还原一级动力学常数较无共基质存在时平均提高(52±6)％.     

Enhanced enzymatic removal of chlorophenols in the presence of co-substrates

The effect of reactive co-substrates such as guaiacol and 2,6-dimethoxyphenol on the removal of chlorinated phenols by horseradish peroxidase (HRP) and a laccase from the fungus Trametes versicolor was investigated. Addition of 50 mM guaiacol enhanced the precipitation of 4-chlorophenol, 2,4-dichlorophenol, and 2,4,5-trichlorophenol with peroxidase by 12, 32 and 65%, respectively, and with laccase by 20, 32 and 80%, respectively. Addition of 10 mM 2,6-dimethoxyphenol enhanced the precipitation of 2,4,5-trichlorophenol by 90% with peroxidase and by 98% with laccase. Products from the reaction of 2,6-dimethoxyphenol and peroxidase were filtered to exclude compounds of a molecular weight greater than 500. Incubation of the resulting enzyme-free filtrate with a solution of unreacted 2,4,5-trichlorophenol caused precipitation and a 72% removal of the 2,4,5-trichlorophenol. Chlorophenol precipitation in the presence of co-substrates may be a useful strategy for improving the efficiency of enzymatic decontamination methods, particularly in the case of heterogenous pollution.     

紫外光解加速喹啉生物降解和矿化的机制

喹啉是一种较难生物降解的有机化合物,为此,分别采用3种方法对喹啉溶液进行生物降解,即直接生物降解（B ）、紫外光解后再进行生物降解（P＋B ）和将草酸加入到喹啉溶液中再进行生物降解（OA＋B）。实验结果表明,采用方法（P＋B）时,其降解和矿化速率比方法B要分别高出27％和40％。通过对喹啉光解中间产物的分析发现,喹啉在光解过程中有草酸的生成,因而推测是草酸作为电子供体,通过共基质的原理加速了喹啉的初始反应速率。这一推测通过直接向喹啉溶液中加入草酸,其降解和矿化速率与经过紫外光解预处理的实验结果相似而得以证明。     

葡萄糖共基质下硝基酚产甲烷毒性研究

在中温（35℃）厌氧间歇试验条件下，以葡萄糖为共基质，通过测定累计产甲烷量，研究了3-硝基酚（3-NP）、2，4-二硝基酚（2，4-DNP）和2，6-二硝基酚（2，6-DNP）的厌氧毒性，并利用相对活性确定了反应时间为24、48、72和96h时3种硝基酚的50％相对抑制浓度。结果表明：当33N-P浓度≤40mg／L时，对产甲烷菌没有产生抑制，反而有促进作用；当浓度为80-160mg／L时产生轻度抑制；当浓度≥320mg／L时产生重度抑制。当32，4-DNP浓度≤10mg／L时，对产甲烷菌不产生抑制；当浓度≥20mg／L时产生重度抑制。当32，6-DNP浓度≤20mg／L时，对产甲烷菌不产生抑制；当浓度为40mg／L时产生轻度抑制；当浓度≥80mg／L时产生重度抑制。根据50％相对抑制浓度判断，3种硝基酚对产甲烷菌活性的抑制大小顺序为2，4-DNP〉2，6-DNP〉3-NP。     

2-硝基酚厌氧毒性和厌氧降解性研究

在中温(35±1)℃厌氧条件下,采用间歇试验方法,研究了2-硝基酚的厌氧毒性和厌氧降解性。厌氧毒性试验结果表明,2-硝基酚的质量浓度小于96mg/L时,对产甲烷菌几乎没有抑制作用,质量浓度界于131mg/L和163mg/L之间时产生轻度抑制,质量浓度大于或等于553mg/L时产生重度抑制。反应时间为24h时2-硝基酚的80%、50%、20%相对抑制质量浓度分别为155、270和690mg/L。厌氧降解性试验结果表明,污水处理厂一级厌氧消化池污泥对2-硝基酚的处理效果好于ABR反应器和UASB反应器的污泥。用污水处理厂一级厌氧消化池污泥作为接种污泥,以葡萄糖为共基质,处理2-硝基酚的效果比用乙酸钠为共基质更好。     

物化及内循环组合工艺处理焦化废水

采用物化与生物结合工艺处理焦化废水,物化系统中主要工艺为除氰及除氮工艺,生物系统采用了厌氧内循环(IC)一共基质条件下好氧内循环结合工艺.好氧内循环工艺以葡萄糖为共基质,池内空间位置上存在好氧及缺氧区,同时将悬浮载体技术引入好氧池,提高了焦化废水中难降解有机物及总氮的去除效果.实现了COD、NH3-N、TN的同时去除.实验结果表明,该工艺运行稳定且处理效果较好.3个月的稳定运行期间,出水COD、NH3-N、TN平均质量浓度分别为62、9、29 mg/L.     

共基质生物刺激技术去除城市河道底泥难降解有机污染物研究

随着城市河道外源污染的有效控制,河道污染底泥的治理在全面解决水体污染中的地位日渐突出。受污染底泥中的难降解有机物长期残留在环境中,对生物和人类健康造成风险。研究采用共基质生物刺激方法,在深圳河污染底泥中单独投加乙酸钠和甲醇,通过试验,利用微生物的共代谢行为,考察有机物去除效果。研究结果表明:(1)深圳河底泥中投加共基质乙酸钠和甲醇后,刺激底泥微生物增殖,进而促进底泥生物降解;(2)使用共基质生物刺激技术可有效去除有机污染物,但对底泥还原状态和黑臭问题并无改善,这可通过后续向底泥投加化学氧化剂加以解决。     

双波长光度法测定共基质降解液中的组分含量

以酸性品红染料和坚木栲胶为实验材料,采用双波长光度法测定染料和植物鞣剂混合液中各组分浓度,为研究染料与植物鞣剂共基质降解性能提供表征方法。酸性品红染料和坚木栲胶溶液标准曲线回归方程分别为△A（458nm-430nm）=0．00491xCdye（R2=0．99992）和,△A（280nm-462nm）=0．01254xCtannin（R2=0．9995）。用双波长光度法测定其精密度、重现性和加样回收率,酸性品红染料和坚木栲胶的RSD分别在0．73％-4．02％和0．60％-4．36％范围内。与利用贡献因子的CODcx测定方法相比较,双波长光度法测定共基质中有色组分的浓度具有简便、快速、准确可靠的特点。