平板玻璃工业窑炉烟气中低温SCR脱硝中试研究

我国平板玻璃工业正面临严峻的NOx控制形势,研究并推广玻璃窑炉高效脱硝技术对玻璃工业发展及大气环境保护均具有重要意义。选择性催化还原(SCR)脱硝技术是国内外公认效率最高的脱硝技术,然而该技术在玻璃窑炉中推广应用还面临诸多技术问题。本研究设计并建设了10 000 Nm3/h的平板玻璃工业窑炉中低温SCR脱硝中试装置,分析了玻璃窑炉烟气组分波动规律及其对SCR脱硝系统的潜在影响,考察了烟气温度、喷氨量控制和烟气处理量等工艺参数,开展了为期6 d的连续运行实验。这些在实际烟气中开展的研究为玻璃窑炉SCR脱硝技术研究分享了大量一手数据和经验。     

SBR法处理保险粉废水

对SBR法处理保险粉废水的可行性进行了研究。结果表明,活性污泥经驯化后能较好地适应保险粉废水。该工艺在悬浮性固体(MLSS)含量为4 g/L,污泥负荷为0.23 kg COD/(kg污泥·d),水力停留时间(HRT)10 h,溶解氧(DO)2~4 mg/L以及实验温度25~35℃,周期为12 h的运行条件下,对COD的去除率为89.3%,完全达到该废水行业排放标准要求。其适宜的污泥龄为20 d,为中试和工艺设计应用提供了参考。     

污泥施入黄土后重金属Cu、Zn、Cd的淋滤迁移

污泥土地利用是目前国内外污泥处置的主要方式和鼓励方向,在中国西北黄土地区更有前景和意义.污泥富含有机质和营养元素可弥补黄土的贫瘠缺陷,改善黄土肥力、增加植物产量.污泥施入黄土后,灌溉水对污泥重金属的淋滤迁移和污染风险是值得研究的课题之一.研究旨在了解重金属Cu、Zn、Cd在黄土层中的淋滤迁移特征,为黄土地区污泥的土地利用及重金属污染控制提供实验依据.实验选择污泥中含量或毒性大的Cu、Zn、Cd 3种重金属作为研究对象,通过室内模拟土柱对表层堆肥污泥中2种源强的重金属进行1年灌溉用水量的淋滤对比实验,测定淋滤前后土柱中和渗出液的Cu、Zn、Cd总量、有机质及pH值,以期分析重金属在黄土中的淋滤、迁移特征.结果表明,淋滤作用可使堆肥污泥Cu、Zn、Cd发生少量迁移并富集于土柱中、上部,大部分或绝大部分重金属仍滞留于耕作层(0～20 cm);淋滤使堆肥污泥Cd与Cu向下迁移约30 cm,Zn向下迁移约20 cm;渗出液呈弱碱性,其中Cu、Zn、Cd 3种重金属的浓度较入渗水均有增多,但随渗出液从黄土柱中溶出的重金属量极少.实验表明,耕作层重金属源强对Cu、Zn、Cd在土柱剖面中的淋滤、迁移和滞留作用以及溶出量均有不同程度的影响,堆肥污泥土地利用可以明显改善黄土肥力,灌溉对耕作层污泥有机质的淋滤损失量较小.并得出,堆肥污泥在黄土地区的土地利用是可行的.     

茜素绿的微波无极紫外光降解及产物分析

以茜素绿为研究对象,探讨了蒽醌类染料在微波无极紫外灯光辐射下的降解行为。结果表明,茜素绿的脱色反应符合一级反应动力学规律,反应120 min后COD和TOC的去除率分别为65.79%和60.98%;采用荧光色谱仪和电子顺磁共振仪检测到降解过程中羟基自由基和超氧自由基为主要活性物种;利用红外光谱仪、离子色谱仪和电子喷雾质谱仪分析了反应过程中的中间产物;采用电喷雾等技术和离子色谱测定了茜素绿降解的中间产物,并推断了茜素绿微波紫外光降解可能的历程;采用大肠杆菌和锦鲤对溶液进行了生物毒性检测与评价,由于中间产物的产生降解溶液的毒性先升后降。     

Discrimination of excess toxicity from narcotic effect: Comparison of toxicity of class-based organic chemicals to Daphnia magna and Tetrahymena pyriformis

The discrimination of excess toxicity from narcotic effect plays a crucial role in the study of modes of toxic action for organic compounds. In this paper, the toxicity data of 758 chemicals to Daphnia magna and 993 chemicals to Tetrahymena pyriformis were used to investigate the excess toxicity. The result showed that mode of toxic action of chemicals is species dependent. The toxic ratio (TR) calculated from baseline model over the experimentally determined values showed that some classes (e.g. alkanes, alcohols, ethers, aldehydes, esters and benzenes) shared same modes of toxic action to both D. magna and T. pyriformis. However, some classes may share different modes of toxic action to T. pyriformis and D. magna (e.g. anilines and their derivatives). For the interspecies comparison, same reference threshold need to be used between species toxicity. The excess toxicity indicates that toxicity enhancement is driven by reactive or specific toxicity. However, not all the reactive compounds exhibit excess toxicity. In theory, the TR threshold should not be related with the experimental uncertainty. The experimental uncertainty only brings the difficulty for discriminating the toxic category of chemicals. The real threshold of excess toxicity which is used to identify baseline from reactive chemicals should be based on the critical concentration difference inside body, rather than critical concentration outside body (i.e. EC₅₀ or IGC₅₀). The experimental bioconcentration factors can be greatly different from predicted bioconcentration factors, resulting in different toxic ratios and leading to mis-classification of toxic category and outliers.     

Effect of initial pH control on biological phosphorus removal induced by the aerobic/extended-idle regime

Recently, it has been reported that biological phosphorus removal (BPR) can be induced by an aerobic/extended-idle (AEI) regime. This study further investigated the effect of initial pH ranging from 6.6 to 8.2 on BPR in the AEI process, and compared the BPR performance between the AEI and the anaerobic/oxic (A/O) regimes under their optimal initial pH value. Experimental results firstly showed that phosphorus removal linearly increased with initial pH increasing from 6.6 to 7.8, but slightly decreased when initial pH increased from 7.8 to 8.2. The optimal initial pH should be controlled at 7.8, and the phosphorus removal at initial pH 7.8 was approximately 1.7-time than that at initial pH 6.6. The mechanism studies showed that the biomass cultured at initial pH 7.8 contained more polyphosphate accumulating organisms (PAOs), lower glycogen accumulating organisms (GAOs), and had higher activities of exopolyphosphatase and polyphosphate kinase than that cultured at initial pH 6.6. Cyclic studies revealed that initial pH control affected the transformations of intracellular polyhydroxyalkanoates and glycogen, which might thereby influence microbial competition between PAOs and GAOs. Then, BPR performance between the AEI and the A/O regimes by adjusting initial pH at 7.8 was also compared. The results showed the AEI regime could drive a better BPR than the generally accepted A/O regime (98% vs 88%). Finally, controlling initial pH at 7.8 to promote BPR in the AEI process was confirmed for a municipal wastewater.     

Halogenated polycyclic aromatic hydrocarbons in the environment

Halogenated polycyclic aromatic hydrocarbons (HPAHs) have been reported to occur in air, sediment, fly ash, and biota samples. This review summarized current existing data on the environmental occurrence, behavior, physicochemical properties, emission sources, and toxic equivalents of HPAHs. Firstly, the physicochemical properties of HPAHs were summarized. Then, an overview of environmental occurrence of HPAHs in ambient matrices including biological samples was reviewed. Meanwhile, the emission sources and possible formation mechanisms of HPAHs were discussed. Apart from that, the aryl hydrocarbon receptor (AhR)-mediated activities were summarized, which indicated that the position and number of halogen atoms on the parent PAHs molecule were important determinant factors affecting the AhR-mediated activity of individual HPAHs congeners. Finally, some research recommendations on HPAHs were given.     

Temperature influence on biological phosphorus removal induced by aerobic/extended-idle regime

Previous researches have demonstrated that biological phosphorus removal (BPR) from wastewater could be driven by the aerobic/extended-idle (A/EI) regime. This study further investigated temperature effects on phosphorus removal performance in six A/EI sequencing batch reactors (SBRs) operated at temperatures ranging from 5 to 30 °C. The results showed that phosphorus removal efficiency increased with temperature increasing from 5 to 20 °C but slightly decreased when temperature continually increased to 30 °C. The highest phosphorus removal rate of 97.1 % was obtained at 20 °C. The biomass cultured at 20 °C contained more polyphosphate accumulating organisms (PAO) and less glycogen accumulating organisms (GAO) than that cultured at any other temperatures investigated. The mechanism studies revealed that temperature affected the transformations of glycogen and polyhydroxyalkanoates, and the activities of exopolyphosphatase and polyphosphate kinase activities. In addition, phosphorus removal performances of the A/EI and traditional anaerobic/oxic (A/O) SBRs were compared at 5 and 20 °C, respectively. The results showed the A/EI regime drove better phosphorus removal than the A/O regime at both 5 and 20 °C, and more PAO and less GAO abundances in the biomass might be the principal reason for the higher BPR in the A/EI SBRs as compared with the A/O SBRs.     

活性炭纤维吸附模拟废气中的乙醇和乙醚

采用动态吸附法研究了5种活性炭纤维（ACF）对乙醇、乙醚及模拟混合废气中的乙醇和乙醚的吸附性能。实验结果表明：当ACF-1,ACF-2,ACF-3,ACF-4分别吸附乙醇和乙醚时,在室温、乙醇质量浓度12.0 mg/L、乙醚质量浓度13.0 mg/L的条件下,4种ACF对乙醇的穿透吸附量和饱和吸附量分别为60~70 mg/g和339~409 mg/g,对乙醚的穿透吸附量和饱和吸附量分别为50~65 mg/g和301~344 mg/g;在室温、模拟混合废气中乙醇和乙醚的质量浓度均为11.6 mg/L、吸附时间120 min的条件下,具有较大的比表面积和微孔体积的ACF-5对乙醇的吸附量为205 mg/g,对乙醚的吸附量为223 mg/g;在脱附真空度-0.95 Pa、脱附时间20 min的条件下,经17 次使用的ACF-5对模拟混合废气中乙醇和乙醚的穿透吸附量均为87 mg/g,穿透时间均为12 min。     

Levels, compositions, and inventory of polybrominated diphenyl ethers in sewage sludge of Guangdong Province, South China

Polybrominated diphenyl ethers (PBDEs) were measured in sewage sludge samples collected from major wastewater treatment plants in Guangdong Province, South China. Concentrations of ∑₃₉PBDE (all 39 compounds including tri- to hepta- PBDE congeners except for BDE-209) ranged from 3.6 to 428 ng/g dw with a mean value of 67.4 ng/g dw and a median value of 25.9 ng/g dw, and those of BDE-209 ranged from 9.9 to 5,010 ng/g dw (mean 1,024 ng/g dw and median 824 ng/g dw). The PBDE mixtures detected were mainly comprised of penta-, octa-, and deca-BDEs, with deca-BDE as the dominant constituent. The most abundant congeners, excluding BDE-209, were BDE-47, BDE-99, and BDE-183. Good correlations were found among the concentrations of BDE-47, BDE-99, BDE-100, BDE-138, and BDE-154 (r?>?0.8). However, poor correlations were found between the concentrations of BDE-209 and all other congeners (r?<?0.3). This fact suggests that most tri- to hepta-BDEs detected did not originate from decomposition of deca-BDE. The estimated annual emission of ∑_allPBDEs, ∑₃₉PBDEs, penta-BDE, octa-BDE, and deca-BDE to the Pearl River Delta environment (PRD), based on the sludge samples analyzed, amounts to 232, 20.2, 5.5, 1.7, and 212 kg per year, implicating sewage sludge as a significant source of PBDEs to the PRD environment.