不同填充剂及复合微生物菌剂对蓝藻堆肥效果的影响

为了研究不同填充剂以及复合微生物菌剂对蓝藻堆肥效果的影响，本实验利用锯末、稻壳、麸皮和米糠为填充剂接种堆肥菌剂与蓝藻进行室内模拟堆肥，设置了稻壳、麸皮为填充剂不加菌剂作对照组，分析了pH值、总碳(TC)、总氮(TN)、碳氮比（C/N）、种子发芽指数(germination index,GI)的动态变化。堆肥结束时处理组麸皮的TC降低了90.43 g/kg，TN增加了1.85 g/kg，C/N降低到13.46，GI升高到73.98%，这都说明麸皮作为填充剂混合蓝藻堆肥的效果较好；添加复合微生物菌剂后，处理组稻壳(60.98%)、处理组麸皮(73.67%)的GI分别比相应的对照组升高了11.02、19.84个百分点，这说明复合微生物菌剂对蓝藻堆肥有促进作用。     

火山石生物滤床对微囊藻毒素的去除

微囊藻水华爆发导致大量微囊藻毒素释放至地表水环境中,严重威胁着饮用水供水安全.通过不同条件火山石自然曝气生物滤床(活性挂膜、灭活挂膜、未挂膜和无填料滤床)对不同形态、构型(MC-LR、MC-RR)的微囊藻毒素的去除实验,探讨其去除效率、途径和机理.结果表明,火山石自然曝气生物滤床对微囊藻毒素的去除是微生物降解和基质吸附共同作用的结果.胞外毒素和胞内毒素的总去除率分别为58％和91％.其中,胞外毒素主要通过微生物降解作用途径去除,占胞外毒素总去除率的(41±4.2)％,胞内毒素则主要通过基质吸附途径去除,占胞内毒素总去除率的(64±5.1)％.生物膜吸附、光降解等其他途径无明显作用.另外,不同构型的微囊藻毒素在火山石自然曝气生物滤床中均能有效去除,MC-LR和MC-RR的去除率分别为68％和54％.     

巢湖和太湖微囊藻毒素差异性研究

采用固相萃取高效液相色谱法检测巢湖和太湖水体中5种微囊藻毒素(MCs)——MC-RR、MC-YR、MC-LR、MC-LA、MC-LY的含量。结果表明,巢湖水体中的MCs以MC-RR、MC-LA、MC-LY为主,太湖水体主要以MC-RR、MC-LR、MC-LA为主,其中太湖MC-LR的最高质量浓度为2.558μg/L,超过《地表水环境质量标准》(GB 3838—2002)中对集中式生活饮用水地表水源地的限定值(1μg/L)。分析巢湖和太湖水体中MCs与水质指标之间的相关性,发现同种MCs与两湖环境因子的相关性存在明显差异。逐步回归拟合结果表明,氨氮和DO分别能与巢湖MC-LR、MC-LY进行拟合;Chl-a、TOC能与太湖MC-LR回归拟合,TOC能与太湖MC-YR进行拟合。由于多数MCs不能通过水质指标的拟合结果来预测,因此在未来研究中需结合环境因子和MCs的遗传机制来共同分析MCs在水中的分布规律。     

阳澄湖和滆湖微囊藻毒素分布及其与富营养化因子的关系

2013年6—10月进行了阳澄湖和滆湖的水样采集及分析,对水体中胞内和胞外3种微囊藻毒素(MC-LR,MCRR,MC-YR)和TN、TP、Chl-a等富营养化指标在两湖的分布情况及关系进行了研究。结果表明,阳澄湖的微囊藻毒素及富营养化因子浓度在不同点位的差异小,而滆湖从北部到南部呈下降趋势,两湖相比,滆湖的浓度远远高于阳澄湖;富营养化因子影响微囊藻毒素的浓度分布和变化;相关性分析表明MC-LR、MC-RR和MC-YR与CODMn、TN、TP、PO3-4-P、Chl-a分别呈极显著正相关性(P0.01),MC-LR、MC-YR与NH+4-N呈显著负相关(P0.05);逐步回归性分析显示Chl-a是影响3种微囊藻毒素浓度的关键因子,可以通过Chl-a对水体中MCs的浓度进行预测,为微囊藻水华和微囊藻毒素污染的预警提供重要的科学参考。     

微囊藻毒素-RR对反硝化细菌生长及生理特性的影响

用0.01、5.00 mg/L微囊藻毒素-RR(MC-RR)处理反硝化细菌,研究了MC-RR对反硝化细菌的生长、培养液中NO3--N和NO2--N含量以及细胞内硝酸还原酶活性的影响.结果表明,高浓度MC-RR能显著抑制反硝化细菌的生长,延缓其细胞增殖,抑制培养液中硝酸盐含量的降低和亚硝酸盐含量的升高以及细胞内硝酸还原酶的活性,因而可能抑制或减缓生态系统中氮循环的进程.这表明,微囊藻毒素在一定程度上可能调节水体细菌群落.     

不同填料载体生物膜对微囊藻毒素的去除效果

利用自行设计的生物膜培养装置,通过对4种不同填料载体进行连续曝气循环培养生物膜,对湖水中的溶解态微囊藻毒素(MCs)的去除作用进行了研究。结果表明,填料载体上生物膜从形成到稳定大约需要3周;生物膜形成后对MCs的去除效率由高到低的顺序是:颗粒活性炭柱>多密孔球型滤料柱>塑料悬浮填料柱>陶瓷滤球柱。在实验水质条件下,当水力停留时间(HRT)=5 h,进水MCs浓度为21.5～47.25μg/L时,颗粒活性炭、多密孔球型滤料柱对MCs的去除率最高可达100%,塑料悬浮填料柱对MC-LR和MC-RR的去除率分别为70%和88%。当HRT=2.5 h时,塑料悬浮填料柱对MC-RR的去除率为MC-LR的2倍。生物膜对MCs的降解效果随温度(5～20℃)和溶解氧的升高而增加。塑料悬浮填料作为合适的生物膜挂膜填料载体对水源水的生物预处理具有良好的应用前景。     

微囊藻毒素-RR的提取和臭氧氧化降解

在对采自云南滇池水华蓝藻细胞中的微囊藻毒素-RR(microcystin-RR,MC-RR)提取并发现其含量达到0.19mg/g(干重)的基础上,重点研究了臭氧氧化降解所提取的MC-RR。结果表明,当反应体系中臭氧浓度为5.7 mg/L时,初始浓度1.9 mg/L的MC-RR在15 min内被完全降解。利用HPLC/ESI/MS对提取的MC-RR及其氧化降解产物质荷比测定发现,降解前MC-RR的质谱图中出现特征离子m/z=1 038.7、m/z=519.8以及m/z=135.0。而降解后的产物质谱图中只有Adda基团中带苯环结构化合物(C9H10O)的特征离子峰m/z=135.0存在,其他2个离子峰完全消失。由此推断反应体系中MC-RR(m/z=1 038.2)在大量臭氧及其.OH自由基全面攻击下,分子结构中Adda基团以及单环结构中的不饱和双键直接被氧化而发生断链,最终形成小分子的有机物。     

碳源对铜绿微囊藻生理特性及微囊藻毒素产率的影响

为研究水体中不同碳源对铜绿微囊藻生理特性的影响,以Na2CO3与葡萄糖分别作为铜绿微囊藻生长的无机碳源与有机碳源,将铜绿微囊藻于光照下进行培养,并对其一系列的生理特性与微囊藻毒素产率进行检测。实验结果表明,同等碳浓度下,有机碳源更能促进铜绿微囊藻的生长,经过30 d的培养,铜绿微囊藻在有机碳源中的产量为187.55 g,比其在无机碳源中的产量提高了6.06%;微囊藻毒素在有机碳源中的产量为969.00μg/g,而在无机碳源中的产量却升高至1 193.60μg/g。参与藻毒素合成的3种氨基酸在无机碳源中的浓度要比有机碳源中的浓度高,但是其余几种氨基酸的含量与之情况相反。而有机碳源培养的铜绿微囊藻总可溶性蛋白含量为387.00μg/g,比无机碳源培养的铜绿微囊藻的蛋白含量提高了93.60%。     

蓝藻与污泥混合厌氧发酵产沼气的初步研究

为了实现太湖蓝藻打捞后的快速处置，对厌氧颗粒污泥、消化污泥、剩余污泥与蓝藻混合厌氧发酵产沼气进行了研究。结果表明，蓝藻与污泥混合可以有效促进沼气发酵。在蓝藻与厌氧颗粒污泥物料比为6∶1时，产气效果最佳，沼气产率为73 mL/g VS，平均甲烷含量为69%，最大产气速率为138 mL/d，累计产甲烷量为50 mL CH₄/g干物质，分别是蓝藻与消化污泥、剩余污泥混合发酵时的1.5倍和2.3倍。厌氧颗粒污泥、消化污泥、剩余污泥与蓝藻混合，其VS降解率为11.40%～13.73 %，COD减少了27.97%～46.38%。厌氧发酵对蓝藻藻毒素的含量有较大影响，分别从356、366和244 μg/L降低到检测限5 μg/L 以下。     

微囊藻毒素-LR降解菌的筛选及降解特性研究

从上海市淀山湖表层水体中筛选分离出了1株降解微囊藻毒素-LR(MC-LR)的细菌并研究了其降解特性。根据细胞形态结构、生理生化特征及其16S rDNA基因序列分析,鉴定分离菌株DHU-28(GenBank序列登录号为HM047512)属嗜麦芽寡养单胞菌(Stenotrophomonas maltophilia)。微囊藻毒素降解实验结果表明,该菌株能在以MC-LR为唯一碳源、氮源的无机盐培养基中生长,6 d内可将初始质量浓度为15 mg/L的MC-LR降解为8.12 mg/L,降解效率达到45.9%。菌株DHU-28的最适生长温度是30℃,最适生长pH为7.0。酵母粉、蛋白胨、葡萄糖等营养物质可以明显促进菌株对MC-LR的降解效率,尤其是加入50 mg/L酵母粉后,6 d降解率达到63.2%。     

Detection of free microcystins in the liver and muscle of freshwater fish by liquid chromatography-tandem mass spectrometry

MC analysis of biological tissue is considered to be very difficult due to the lack of validated methods. This is the primary limiting factor for monitoring potential risks in both the flesh of aquatic organisms and the aquatic ecosystem. In this study, an effective method to determine free MCs (MC-LR and MC-RR) in the muscle and liver tissues of freshwater cultured fish was developed using solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC/MS-MS). The extraction solvent, time of extraction, eluent and purification of the extract were optimized. Various SPE cartridges were also investigated. In this optimized analytical procedure, an 85% methanol/water solution (v/v) was selected as the extraction solvent, after which the extracts were purified by removing fats and proteins; a HLB cartridge was chosen for MCs enrichment; and 90% methanol containing 0.02% formic acid/water solution (v/v) was used as the eluent. Under the optimized pretreatment conditions and instrument parameters, good recoveries of MC-LR and MC-RR were obtained at three concentrations (0.5, 1.0 and 2.0 µg g^?1 dry weight (DW)), with values ranging from 92.5 to 98.3% and 92.1 to 98.6%, respectively. The method detection limit (MDL) for muscle samples was 0.5 µg kg^?1 and 0.4 µg kg^?1 (DW) for MC-LR and MC-RR, respectively. The MDL for the liver samples was 0.8 µg kg^?1 (DW) for both MC-LR and MC-RR. The developed procedure was successfully applied to analyze MCs in the muscle and liver of fish samples collected from a Chinese freshwater aquaculture pond during bloom seasons. The MC-LR concentrations ranged from below the MDL to 4.17 µg kg^?1 and the MC-RR concentrations ranged from below the MDL to 2.64 µg kg^?1.     

Sequential extraction of heavy metals during composting of sewage sludge

The major limitation of soil application of sewage sludge compost is the total heavy metal contents and their bioavailability to the soil-plant system. This study was conducted to determine the heavy metal speciation and the influence of changing the physico-chemical properties of the medium in the course of composting on the concentrations, bioavailability or chemical forms of Cu, Zn, Pb and Ni in sewage sludge. Principal physical and chemical properties and FTIR spectroscopical characterization of sludge compost during treatment show the stability and maturity of end product. The total metal contents in the final compost were much lower than the limit values of composts to be used as good soil fertilizer. Furthermore, it was observed by using a sequential extraction procedure in sludge compost at different steps of treatment, that a large proportion of the heavy metals were associated to the residual fraction (70-80%) and more resistant fractions to extraction X-NaOH, X-EDTA, X-HNO3 (12-29%). Less than 2% of metals bound to bioavailable fractions X-(KNO3+H2O). Heavy metal distribution and bioavailability show some changes during composting depending on the metal itself and the physico-chemical properties of the medium. Bioavailable fractions of all elements tend to decrease except Ni-H2O. Zn and mainly Cu present more affinity to organic and carbonate fractions. In contrast, Pb is usually preferentially bound to sulfide forms X-HNO3. Nickel shows a significant decrease of organic form. Significant degrees of correlation were found between heavy metal fractions and changes of some selected variables (e.g. pH, ash, organic matter, humic substance) during the course of composting. Mobile fractions of metals are poorly predictable from the total content. The R2 value was significantly increased by the inclusion of other variables such as the amount of organic matter (OM) and pH.     

AMMONIA REMOVAL FROM COMPOST LACHATE USING ZEOLITE. II. A STUDY USING CONTINUOUS FLOW PACKED COLUMNS

Bench-scale packed zeolite columns were set up and operated to investigate the continuous removal of ammonium ions from compost leachate. The effects of hydraulic retention time (HRT), and particle size of the zeolite on the ammonia adsorption capacity were studied. For both the coarse particle and the powdered zeolite columns, higher ammonia removal efficiencies were achieved with longer HRT (i.e., lower influent flow rate) tests. At the same HRT, ammonia removal efficiencies from tests with powdered zeolite were generally 20% higher than tests with the coarse particle zeolite. A HRT of 6 hours was found appropriate for efficient ammonia removal, and an operating capacity of 1.31 mg N/g zeolite was obtained. Over 98% of the ammonia input from the influent was consistently removed for over 5 bed volumes (BV) of compost leachate flowing through the zeolite column. Zeolite proved to have a great potential as a medium for ammonia removal in treating composting leachate.     

Ammonia removal from compost leachate using zeolite. II. A study using continuous flow packed columns

Bench-scale packed zeolite columns were set up and operated to investigate the continuous removal of ammonium ions from compost leachate. The effects of hydraulic retention time (HRT), and particle size of the zeolite on the ammonia adsorption capacity were studied. For both the coarse particle and the powdered zeolite columns, higher ammonia removal efficiencies were achieved with longer HRT (i.e., lower influent flow rate) tests. At the same HRT, ammonia removal efficiencies from tests with powdered zeolite were generally 20% higher than tests with the coarse particle zeolite. A HRT of 6 hours was found appropriate for efficient ammonia removal, and an operating capacity of 1.31 mg N/g zeolite was obtained. Over 98% of the ammonia input from the influent was consistently removed for over 5 bed volumes (BV) of compost leachate flowing through the zeolite column. Zeolite proved to have a great potential as a medium for ammonia removal in treating composting leachate.     

Dynamics of microcystins-LR and -RR in the phytoplanktivorous silver carp in a sub-chronic toxicity experiment

A sub-chronic toxicity experiment was conducted to examine tissue distribution and depuration of two microcystins (microcystin-LR and microcystin -RR) in the phytoplanktivorous filter-feeding silver carp during a course of 80 days. Two large tanks (A, B) were used, and in Tank A, the fish were fed naturally with fresh Microcystis viridis cells (collected from a eutrophic pond) throughout the experiment, while in Tank B, the food of the fish were M. viridis cells for the first 40 days and then changed to artificial carp feed. High Performance Liquid Chromatography (HPLC) was used to measure MC-LR and MC-RR in the M. viridis cells, the seston, and the intestine, blood, liver and muscle tissue of silver carp at an interval of 20 days. MC-RR and MC-LR in the collected Microcystis cells varied between 268-580 and 110-292 microg g(-1) DW, respectively. In Tank A, MC-RR and MC-LR varied between 41.5-99.5 and 6.9-15.8 microg g(-1) DW in the seston, respectively. The maximum MC-RR in the blood, liver and muscle of the fish was 49.7, 17.8 and 1.77 microg g(-1) DW, respectively. No MC-LR was detectable in the muscle and blood samples of the silver carp in spite of the abundant presence of this toxin in the intestines (for the liver, there was only one case when a relatively minor quantity was detected). These findings contrast with previous experimental results on rainbow trout. Perhaps silver carp has a mechanism to degrade MC-LR actively and to inhibit MC-LR transportation across the intestines. The depuration of MC-RR concentrations occurred slowly than uptakes in blood, liver and muscle, and the depuration rate was in the order of blood>liver>muscle. The grazing ability of silver carp on toxic cyanobacteria suggests an applicability of using phytoplanktivorous fish to counteract cyanotoxin contamination in eutrophic waters.     

Long-term operation of biofilters for biological removal of ammonia

Biological removal of ammonia was investigated using two types of packing materials, compost and sludge in laboratory-scale biofilters (8l reactor volume). The aim of this study is to investigate the potential of unit systems packed with these supports in terms of ammonia emissions treatment. Experimental tests and measurements included analysis of removal efficiency, metabolic products, and results of long-term operation. The inlet concentration of ammonia applied was 20-200 mg m-3. The ammonia loading rates of 24.9-566 g NH3 m-3 d-1 to compost biofilter (BF3) and 24.9-472 g NH3 m-3 d-1 to sludge biofilter (BF4) were applied for 210 days, respectively. Removal efficiencies of the compost and sludge biofilters were in the range of 97-99% and 95-99%, respectively when the inlet concentration of ammonia was below 110 mg m-3, and the maximum elimination capacities were 288 and 243 g NH3m-3d-1, respectively. However, removal efficiency and elimination capacity of both biofilters significantly decreased as the inlet concentration increased to above 110 mg m-3. By using kinetic analysis, the maximum removal rate of ammonia, Vm, and the saturation constant, Ks, were determined for both packing materials and the value of Vm for compost was found to be larger. Periodic analysis of the biofilter packing materials showed the accumulation of the nitrification product NO3- in the operation. During the experiment, the pressure drops measured were very low. The use of both packing materials requires neither nutritive aqueous solution nor buffer solution.     

Removal of DEHP in composting and aeration of sewage sludge

The potential of composting and aeration to remove bis(2-ethylhexyl) phthalate (DEHP) from municipal sewage sludge was studied with two dewatered sludges: raw sludge and anaerobically digested sludge. Composting removed 58% of the DEHP content of the raw sludge and 34% of that of the anaerobically digested sludge during 85 days stabilisation in compost bins. A similar removal for the anaerobically digested sludge was achieved in a rotary drum in 28 days. Less than 1% of DEHP was removed with the compost leachate. Although DEHP removal was greater from raw sludge compost than anaerobically digested sludge compost, the total and volatile solids removals were on the same level in the two composts. In the aeration of raw sludge at 20 degrees C the DEHP removals were 33-41% and 50-62% in 7 and 28 days, respectively. Both composting and aeration are concluded to have the potential to reduce the DEHP contents typically found in sewage sludges to levels acceptable for agricultural use.     

接种外源微生物菌剂对香蕉茎秆堆肥的影响

为了研究接种外源微生物菌剂对香蕉茎秆堆肥的影响,本实验采用高温好氧堆肥技术,设计了对照（不接菌）、接种白腐菌及棱盖多孔菌3个处理,探讨了不同处理堆肥过程中堆体温度、水分、pH值、电导率、有机碳、C/N、发芽指数及堆肥质量的变化情况。结果表明,接种微生物菌剂处理的温度均高于对照,且高温期持续时间相对较长,以接种白腐菌处理的高温持续时间最长;接种外源微生物菌剂对堆肥含水率、pH、EC、全碳、C/N变化影响不大;与对照相比,接种白腐菌可增加全氮及全钾的含量,有利于提高堆肥产品质量;接种白腐菌处理在36 d（GI〉50%）就达到腐熟,比对照提前8 d腐熟,明显缩短堆肥腐熟时间;而接种棱盖多孔菌处理比对照推迟10 d腐熟,共需54 d不利于香蕉茎秆堆肥的进行。     

二丁与连翘药渣联合堆肥腐熟度评价

为了对不同比例的二丁与连翘药渣堆肥腐熟度进行评价,采用条垛式好氧堆肥方式,将二丁和连翘两种药渣按照5种不同的比例进行堆肥处理,通过分析堆肥过程中温度、pH、C/N和发芽指数等指标的变化规律,对堆肥腐熟度进行评价。结果表明:在试验处理条件下及堆肥周期内,单一药渣堆肥的两组处理未能完全腐熟,混合药渣堆肥的3组处理均已达到完全腐熟的标准,说明两种药渣混合后进行堆肥,可以有效促进堆肥的顺利进行,且二丁与连翘比例为2∶1(质量比)时发酵效果最好。3组混合药渣的发酵产物可以作为有机肥或土壤改良剂施用,也可以与化肥配合,制备成有机/无机配方肥。