混凝过程中铝盐水解聚合反应平衡的流体动力学控制

为了明确混凝过程中搅拌剪切等动力学因素对铝盐水解聚合反应平衡的影响,采用配制模拟水样作为混凝水系,用Ferron逐时络合比色法对水解产物形态进行表征,并将获取结果与用去离子水组成的纯净水系获取的结果进行对比分析.同时,研究了模拟混凝水系中搅拌剪切条件对铝盐水解反应产物形态分布的影响,考查了铝盐的碱化度和模拟混凝水系的pH值对混凝体系中搅拌剪切条件作用于铝盐水解产物形态分布的影响,并提出了体系搅拌剪切条件影响混凝水系中铝盐水解反应平衡的作用机理.结果表明,混凝过程中的铝盐水解产物形态分布明显受到体系搅拌剪切条件的影响,并且随着混凝水系中铝盐水解程度的增大和转化率的提高,铝盐的水解产物形态分布受到反应体系中搅拌剪切条件的影响加大.     

DO对水解酸化池与好氧MBR组合工艺运行效果的影响研究

针对溶解氧（DO）、气水比对水解酸化池与好氧MBR组合工艺处理污水效果的影响和能耗问题．从气水比对DO的影响,DO对COD与色度去除效果的影响等方面来讨论气水比,溶解氧以及污水处理效果之间的最佳运行点。试验结果表明。在P（MLSS）分别为5．81、4．25、2．19g／L的运行条件下,MBR的最佳气水比为39：1、28．1.18：1;DO变化速率随污泥浓度的下降而升高;DO的变化对COD、色度的去除效果影响并不显著。     

Enzymatic treatment of estrogens and estrogen glucuronide

Natural and synthetic estrogens from sewage treatment systems are suspected to influence the reproductive health of the animals in the rivers.In this article we investigated the enzymatic treatment of three estrogens (estrone,17β-estradiol,and 17α-ethynyletstradiol) by a fungal laccase which oxidize phenolic compounds with dissolved oxygen.The elimination of the estrogenic activities by enzymatic oxidation was demonstrated by medaka vitellogenin assay.In addition,we developed an enzymatic treatment system comprised of β-D-glucuronidase and the laccase for 17β-estradiol 3-(β-D-glucuronide) degradation.The two enzymes eliminated 17β-estradiol 3-(β-D-glucuronide) and the intermediate,17β-estradiol,efficiently.     

Abiotic degradation of four phthalic acid esters in aqueous phase under natural sunlight irradiation

Abiotic degradability of four phthalic acid esters (PAEs) in the aquatic phase was evaluated over a wide pH range 5–9. The PAE solutions in glass test tubes were placed either in the dark and under the natural sunlight irradiation for evaluating the degradation rate via hydrolysis or photolysis plus hydrolysis, respectively, at ambient temperature for 140 d from autumn to winter in Osaka, Japan. The e ciency of abiotic degradation of the PAEs with relatively short alkyl chains, such as butylbenzyl phthalate (BBP) and di-nbutyl phthalate (DBP), at neutral pH was significantly lower than that in the acidic or alkaline condition. Photolysis was considered to contribute mainly to the total abiotic degradation at all pH. Neither hydrolysis nor photolysis of di-ethylhexyl phthalate (DEHP) proceeded significantly at any pH, especially hydrolysis at neutral pH was negligible. On the other hand, the degradation rate of diisononyl phthalate (DINP) catalyzed mainly by photolysis was much higher than those of the other PAEs, and was almost completely removed during the experimental period at pH 5 and 9. As a whole, according to the half-life (t1=2) obtained in the experiments, the abiotic degradability of the PAEs was in the sequence: DINP (32–140 d) > DBP (50–360 d), BBP (58–480 d) > DEHP (390–1600 d) under sunlight irradiation (via photolysis plus hydrolysis). Although the abiotic degradation rates for BBP, DBP, and DEHP are much lower than the biodegradation rates reported, the photolysis rate for DINP is comparable to its biodegradation rate in the acidic or alkaline condition.     

Kinetic analysis of waste activated sludge hydrolysis and short-chain fatty acids production at pH 10

The accumulation of short-chain fatty acids (SCFAs), a preferred carbon source for enhanced biological phosphorus removal microbes, was significantly improved when waste activated sludge (WAS) was fermented at pH 10. The kinetics of WAS hydrolysis and SCFAs production at pH 10 were investigated. It was observed that during WAS anaerobic fermentation at pH 10 the accumulation of SCFAs was limited by the hydrolysis process, and both the hydrolysis of WAS particulate COD and the accumulation of SCFAs followed first-order kinetics. The hydrolysis and SCFAs accumulation rate constants increased with a increasing of temperature from 10 to 35℃, which could be described by the Arrhenius equation. The kinetic data further indicated that SCFAs production at pH 10 was a biological process. Compared with the experiment of pH uncontrolled (blank test), both the rate constants of WAS hydrolysis and SCFAs accumulation at 20℃ were significantly improved when WAS was fermented at pH 10.     

Combination eect of pH and acetate on enzymatic cellulose hydrolysis

The productivity and eciency of cellulase are significant in cellulose hydrolysis. With the accumulation of volatile fatty acids (VFAs), the pH value in anaerobic digestion system is reduced. Therefore, this study will find out how the pH and the amount of acetate inuence the enzymatic hydrolysis of cellulose. The eects of pH and acetate on cellulase produced from Bacillus coagulans were studied at various pH 5-8, and acetate concentrations (0-60 mmol/L). A batch kinetic model for enzymatic cellulose hydrol...     

络合剂对剩余污泥厌氧酶水解的影响研究

研究了厌氧条件下,单独添加络合剂柠檬酸钠（SC）、酶及两者联合添加对城市剩余污泥水解效率的影响.实验结果表明,络合剂SC和酶联合添加可以在一定程度上提高污泥水解效率,且相对单独添加SC或酶,SC与酶联合添加时的处理效果更好.同一温度下（50℃）,单独投加0.294g·g-1（以干污泥DS计）SC时,污泥SCOD/TCO...     

Biocontainment of polychlorinated biphenyls (PCBs) on flat concrete surfaces by microbial carbonate precipitation

In this study, a biosealant obtained from microbial carbonate precipitation (MCP) was evaluated as an alternative to an epoxy-coating system. A bacterium Sporosarcina pasteurii strain ATCC 11859, which metabolizes urea and precipitates calcite in a calcium-rich environment, was used in this study to generate the biosealant on a PCB-contaminated concrete surface. Concrete cylinders measuring 3 in (76.2 mm) by 6 in (152.4 mm) were made in accordance with ASTM C33 and C192 and used for this purpose. The PCB, urea, Ca(2+), and bacterial cell concentrations were set at 10 ppm, 666 mM, 250 mM, and about 2.1 × 10(8) cells mL(-1), respectively. The results indicate that the biosealed surfaces reduced water permeability by 1-5 orders of magnitude, and had a high resistance to carbonation. Since the MCP biosealant is thermally stable under temperatures of up to 840 °C, the high temperatures that normally exist in the surrounding equipment, which may contain PCB-based fluids, have no effect on the biosealed surfaces. Consequently, there is greater potential to obtain a stronger, coherent, and durable surface by MCP. No measurable amount of PCBs was detected in the permeating water, indicating that the leaching water, if any, will have a minimum impact on the surrounding environment.     

紫花苜蓿改良盐渍土对土壤微生物活性和养分含量的影响

为探讨干旱地区种植紫花苜蓿改良盐渍土对土壤微生物生物量及其活性和土壤养分的影响,选择河西走廊黑河流域国有临泽农场的草甸盐土荒地作为对照,研究了种植紫花苜蓿2、3、4年后的改土效果。结果表明：与CK相比,连续种植4年后,所测定的土壤化学性质和微生物化学性质指标都发生了极显著（P〈0.01）的有利变化,电导率下降5.96 mS.cm-1,pH下降0.25,有机碳增加1.50 g.kg-1,微生物生物量碳增加48.93 mg.kg-1,微生物熵上升0.43%,荧光素二乙酸酯水解率提高10.87μg.g-1.h-1,碱解氮增加17.37 mg.kg-1,速效磷增加2.87 mg.kg-1,速效钾增加44.93 mg.kg-1。相关分析表明,微生物生物量碳、微生物熵、荧光素二乙酸酯水解率、碱解氮、速效磷、速效钾与土壤有机碳之间极显著（P〈0.01）正相关,相关系数分别为0.86、0.80、0.87、0.85、0.79、0.80,而与电导率之间极显著（P〈0.01）负相关,相关系数分别为-0.83、-0.79、-0.84、-0.86、-0.88、-0.78。研究认为,种植紫花苜蓿对草甸盐土有显著的改良效果,电导率下降,有机碳含量提高,微生物活性增强,速效养分含量增加。     

烷基多苷促进污泥水解产酸的研究

采用向污泥中投加生物表面活性剂烷基多苷(APG)的方法,研究了APG投加量和水解时间对剩余污泥水解产酸过程的影响.结果表明,APG显著降低污泥表面张力,强化污泥水解,在最适投加量(以TSS计,下同)0.2 g·g-1下,SCOD、蛋白质和可溶性糖的浓度均在12h内达到最大,分别由初始的4 280.2、1 122.9和246.5 mg·L-1上升到6 481.1、1 639.3和1 205.8mg·L-1,同时短链脂肪酸(SCFAs)浓度由1 309.9 mg·L-1增加为2 221.6 mg·L-1,且SCFA的组分分布随之改变,APG投加量越大,SCFAs达到最大浓度所需时间也随之延长.随着APG投加量的增大,α-葡萄糖苷酶相对活力由1.5升至2.5,而蛋白酶相对活力在低投加量下由1.4升至1.9,高投加量下降至1.5.不论APG是否存在,α-葡萄糖苷酶和蛋白酶的活力在达最高后都随着水解时间的延长而逐渐降低.整个过程中pH均呈现先减小后增大的趋势.