不同通风方式对污泥堆肥的影响

采用2种通风方式和5种调理剂进行污泥堆肥,堆温均能顺利达到设定温度(60℃),并能保持一段高温期,堆肥产品的卫生学指标达到了无害化国家标准.同采用正压强制通风相比,采用自然通风与正压强制通风相结合方式,堆温上升迅速,能耗更低.但正压强制通风能加快堆料含水率的降低和有机质的降解.堆料含水率能极大地影响污泥堆肥过程,堆料的含水率不宜超过80%,在污泥堆肥过程中不必对堆料的pH值进行调整.     

酵母生产剩余污泥和糖渣混合堆肥试验研究

堆肥是世界范围内处理有机固体废弃物的一种普遍工艺,本试验以酵母生产副产物糖渣和污泥为原料,以谷糠为填充料,以RW促腐剂为发酵菌剂,按一定比例混合后堆肥,研究了污泥和糖渣混合堆肥的可行性以及处理过程中温度、含水率、pH、有机质、重金属、卫生学等指标的变化规律。试验结果表明,污泥和糖渣混合堆肥具有可行性,初始含水率控制在60%左右,添加一定量的发酵菌种和填充料,并控制合适的翻堆频率,可以顺利实现堆体升温发酵腐熟,并最终满足污泥糖渣无害化、减量化要求。     

城市污水厂污泥堆肥中试实验研究

城市污水厂污泥由于产生量大且成分复杂,如何对它进行稳定化、无害化处理已越来越受到人们的关注.本研究基于好氧发酵仓式堆肥系统,研究了城市污泥处理过程中温度、含水率、pH、有机质、水溶性有机碳、总氮和发芽指数等指标参数的变化规律.研究结果表明:当物料初始含水率控制在65%左右时,在强制通风量112.5m3/12hr,搅拌频率30min/24hr的工艺条件下,堆肥过程可以实现顺利升温并在55℃以上维持3天,满足杀灭致病菌要求的条件;14天反应周期结束时,物料含水率、水溶性有机碳和有机质含量显著降低,堆肥产品腐熟,卫生学指标达到了美国EPA污泥产品A类标准;得到的污泥产品成为性质优良的土壤质量调节剂.     

城市污水厂污泥快速好氧堆肥技术研究

以污泥静态堆肥工艺为基础,针对上海曲阳污水处理厂的脱水污泥进行动态好氧堆肥处理工艺研究,重点研究了控制参数和评价参数(温度、含水率、pH、水溶性有机碳和发芽指数等)变化规律.结果表明:污泥堆肥过程中,含水率、物料温度、水溶性有机碳、发芽指数等指标变化规律性强,效果指示性明显,均可选作堆肥腐熟度的表征参数或评价参数.在优化工艺条件下,通过添加适量的木屑和回流物料,控制物料初始含水率在60%±2%时,堆肥处理可以实现顺利升温并在>55℃维持4d,100%杀灭了病原菌;14d反应周期结束时,物料含水率显著降低,水溶性有机质降解50%左右,出料松散且无臭味,堆肥产品腐熟,卫生学指标达到了我国标准和美国EPA污泥产品A类标准.     

生物表面活性剂在农业废物好氧堆肥中的应用

以稻草秸秆和麸皮为堆肥原料,本实验室制取的鼠李糖脂为促进剂,进行了控温条件下堆肥一次发酵的实验研究.堆肥采用好氧静态堆肥技术,含水率控制在60%～70%,通气量采用时间控制方式,发酵周期18d.实验分析了堆肥过程中有机质、pH值、水溶性有机碳、微生物种群密度、半纤维素酶活、羧甲基纤维素酶活、半纤维素和纤维素含量等指标随时间的变化特征.实验结果表明,堆肥过程中,实验组的有机质降解率比对照样高13.4%,水溶性有机碳的平均含量提高了2.2g/kg,同时半纤维素和纤维素的降解率分别增加了5.7%、10.7%.研究表明,添加鼠李糖脂能够改善堆肥处理的微环境,增强聚合物的水合程度,促进有机质降解,从而加快堆肥进程,提高堆肥产品品质.     

高水分蔬菜废物和花卉、鸡舍废物联合堆肥的中试研究

以滇池流域的典型农业废物蔬菜、花卉废物和鸡舍废物为原料,进行了不同配比的联合堆肥中试研究.一次发酵采用温度反馈通气量控制的静态好氧堆肥系统,二次发酵采用周期性翻堆自然腐熟.在一次发酵阶段,堆体温度在55℃以上保持至少3d,最高温度达73.3℃,可有效杀灭致病菌;堆体含水率从75%降低到56%,多余水分得到快速去除;有机质从65%降低到50%,pH值稳定在8.二次发酵后堆肥产物的腐熟度和养分分析结果表明,产物稳定性好,养分含量高.通过堆肥工艺的优化控制,蔬菜废物、花卉废物和鸡舍废物联合堆肥可以获得高质量的堆肥产品,废物还田能有效减少固体废物非点源污染、提高土壤肥力.     

高水分蔬菜废物和花卉废物批式进料联合堆肥的中试

以滇池流域典型农业废物蔬菜(西芹)和花卉废物(石竹)为原料,进行了2种配比的蔬菜废物和花卉废物联合堆肥的中试研究.堆肥一次发酵采用批式进料温度反馈通气量控制的静态好氧技术,发酵周期15d.对于西芹与石竹废物各占一半的堆肥试验,在一次发酵阶段,堆体温度在55℃以上保持10d,最高温度达65℃,可有效杀灭致病菌,堆体含水率从64.2%减少为46.3%,有机质含量从74.7%下降到55.6%,体积减少为原来的一半,pH值稳定在7左右.二次发酵采用周期性翻堆,自然腐熟,周期30d.对堆肥产物的腐熟度和养分分析表明,堆肥产物稳定性好,养分含量高.这表明,采用温度反馈通气量控制的静态好氧堆肥技术,蔬菜废物和花卉废物联合堆肥可以在45d内获得高质量的堆肥产品,将堆肥产品返还土壤能有效减少固体废物非点源污染、提高土壤肥力.     

蘑菇渣和玉米芯对污泥生物干化的影响研究

文章以蘑菇渣、玉米芯以及两者的混合作为3种调理剂,将污泥与调理剂按一定比例混合,考察相同质量配比不同调理剂条件下,各处理干化过程中的温度、含水率和有机质含量的变化情况,从而确定最佳的调理剂,探讨调理剂对污泥生物干化的影响。结果表明,玉米芯做调理剂时处理实验效果最佳,最高温度达到69.0℃,所经历的时间最短为108 h,玉米芯的添加更能增加反应的升温能力;3个处理实验的含水率总体呈现下降的趋势,其中混合料为调理剂时下降趋势最明显,最终含水率都低于40%,达到相关用泥质量标准,水分脱除效果好;有机质含量较高,总体变化不明显,有利于污泥后续利用。     

城市污水处理厂剩余污泥堆肥的实验研究

污泥由于产量大且成分比较复杂,如何对它进行无害化,稳定化处理,使其成为替代资源已经越来越受到人们的关注。基于好氧堆肥装置系统,以徐州市某污水处理厂的剩余污泥为研究对象,研究了污泥处理过程中温度、含水率、有机质、有机碳以及pH值和重金属等指标的变化规律。研究结果表明：采用污泥与稻草的体积比为1：2的比例堆肥,控制初始含水率为70％左右,可顺利实现升温。堆肥15d后,物料含水率、有机质、有机碳都有了明显的降低;总氮、总磷以及水溶性钾的含量都有了不同程度的增加;重金属含量有了一定程度的降低,符合堆肥的要求。     

污水厂污泥堆肥及制作复合化肥技术与应用

污水处理厂污泥脱水后,加入粉煤灰调节含水率,然后在发酵罐中好氧发酵,使污泥熟化,含水率进一步减少,并且杀灭污泥中的有害微生物。堆肥后的污泥与秸杆、化肥混合制成一种复合化肥,将化肥用在农田的水稻种植,水稻的亩产量增产11.4%,各项指标均符合国家标准。     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Removal of cadmium using MnO2 loaded D301 resin

MnO2 loaded weak basic anion exchange resin D301 （Anion exchange resin, macroreticular weak basic styrene） as adsorbent has been prepared and applied to the removal of cadmium. The adsorption characteristics have been investigated with respect to effect of pH, equilibrium isotherms, removal kinetic data, and interference of the coexisting ions. The results indicated that the Cd^2＋ could be efficiently removed using MnO2 loaded D301 resin in the pH range of 3-8 from aqueous solutions with the co-existence of high concentration of alkali and alkaline-earth metals ions. The saturate adsorption capacity of the Cd^2＋ was 77.88 mg/g. The adsorption process followed the pseudo first-order kinetics. The equilibrium data obtained in this study accorded excellently with the Langmuir adsorption isotherm.     

Effect of coagulation pretreatment on the fouling of ultrafiltration membrane

The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.     

Penetration analysis of elements and bioleaching treatment of spent refractory for recycling

Acidithiobacillus ferrooxidans ATCC23270 and Acidithiobacillus thiooxidans TM-32 were used for bioleaching of spent refractories of aluminium and copper melting furnaces for their recycling.Firstly,penetration of elements into aluminium melting furnace refractory was investigated and it was found that up to 7 cm from surface was contaminated.Comparison on leaching efficiency by the strains ATCC23270 and TM-32 found that the strain ATCC23270 could treat larger amount of the refractories than the strain TM-32 could do.In the experiment of bioleaching of spent refractory aluminium melting furnace by the strain ATCC23270,high leaching efficiency were obtained on Al,Si,and Ca,and extremely low leaching performance was,however,shown on the rest of elements i.e.,Na,Mn,and Zn.Under the strain TM-32 use,relatively high leaching performance was recognized on Al,Si,Ca,Na,Mn,and Zn.In the experiment of bioleaching for spent refractory copper melting furnace,almost the same leaching trends were shown on Cu,Zn,Al,and Si under the strains ACTT23270 and TM-32 uses.     

Simultaneous removal of ammonium and phosphate by zeolite synthesized from coal fly ash as influenced by acid treatment

Zeolite synthesized from fly ash （ZFA） without modification is not efficient for the purification of NH4＋ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacity. To develop an effective technique to enhance the removal efficiency of ammonium and phosphate at low concentrations, ZFA was modified with acid treatment and the simultaneous removal of ammonium and phosphate in a wide range of concentration was investigated. It was seen that when compared with untreated ZFA, only the treatment by 0.01 mol/L of H2SO4 significantly improved the removal efficiency of ammonium at low initial concentrations. The behavior was well explained by the pH effect. Treatment by more concentrated H2SO4 led to the deterioration of the ZFA structure and a decrease in the cation exchange capacity. Treatment by 0.01 mol/L H2SO4 improved the removal efficiency of phosphate by ZFA at all initial P concentrations, while the treatment by concentrated H2SO4 （≥0.9 mol/L） resulted in a limited maximum phosphate immobilization capacity （PIC）. It was concluded that through a previous mild acid treatment （e.g. 0.01 mol/L of H2SO4）, ZFA can be used in the simultaneous removal of NH4＋ and P at low concentrations simulating real effluent.