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.     

河湖疏浚底泥与固废物好氧堆肥研究

研究了不同比例的河湖底泥与固废物混合物在堆肥过程中温度、pH值、含水率、有机质、全氮和碳氮比[ρ(C)∶ρ(N)]等的变化特征.结果表明:含水率保持在60%左右有利于堆肥的腐熟,过高的含水率延长堆肥的腐熟时间;底泥堆肥有机质质量分数不应低于15%;ρ(C)∶ρ(N)保持在25～30:1.添加猪粪和稻壳效果较好,未屑分解较慢,加入尿素等无机氮肥有利于堆肥的腐熟.     

纤维素酶促进绿化废弃物堆肥腐熟的初步研究

为探索新型添加剂对绿化废弃物堆肥腐熟的促进效果,设计添加纤维素酶结合生物菌剂的绿化废弃物室内模拟低温堆肥试验,将纤维素酶分别以0%、2%、4%的比例与微生物菌剂、尿素和绿化废弃物混配,选取T值、HA/FA、GI、E4/E6共4项评价指标并运用模糊综合评价法对处理T1~T10的堆肥腐熟度进行评价。结果表明:纤维素酶与菌剂的结合有降低堆肥p H和提升EC的作用;添加4%纤维素酶与2%菌剂组合的腐熟效果最优;经纤维素酶与菌剂两因素极差分析表明纤维素酶对试验指标影响效果大于菌剂;添加0.8%尿素与酶、菌剂组合不能有效提高腐熟度,一定程度抑制了发酵进程。综上,纤维素酶与菌剂结合作绿化废弃物堆肥促腐添加剂具有可行性。     

VT菌剂对规模养猪场粪便高温堆肥腐熟进程的影响

为分析VT菌剂作为添加材料对农场尺度畜禽粪便高温堆肥腐熟进程的影响,以猪粪和发酵床垫料废弃物为试验材料进行了野外条垛式好氧堆制试验,监测堆肥过程中物料腐熟动态变化。结果表明:添加初始物料鲜质量0.2%的VT菌剂使堆肥49 d有效积温相对提高12%,水分散失速率相对提高46%,有机质累积降解率相对提高4%;VT菌剂的添加对堆肥过程中物料pH值、电导率(EC)、发芽率指数(GI)以及无机氮等腐熟指标变化规律产生了一定程度的影响,但总体影响较不显著;在添加VT菌剂的条件下,猪粪与垫料废弃物条垛式堆肥时间不宜少于35 d。     

密闭式堆肥反应器中复合微生物菌剂对堆肥效果的影响

通过一套自制密闭式堆肥反应器系统,研究在一定的堆肥条件下,接种复合微生物菌剂对堆肥腐熟度、环境影响控制和产品质量等方面的影响。通过对堆肥温度、含水率、碳氮比(C/N)、发芽指数(GI)、氨气(NH3)排放浓度和微生物数量等指标的检测分析发现,接种复合微生物菌剂的处理组提前3.5~4.5h到达高温期,高温期持续时长多于对照3.8~4.0 d,氧气消耗快,堆肥腐熟速度快,腐熟程度高,氨气排放浓度平均低于不接种处理39%,有效地控制了臭气排放和氮素损失。认为在堆肥中接种复合微生物菌剂是解决我国目前堆肥腐熟时间过长、养分损失大、恶臭气体排放严重、环境影响严重等问题的有效途径。     

添加外源微生物对城市生活垃圾堆肥腐熟的影响

文章探究高效、低成本的圾堆肥技术,为城市生活垃圾的无害化处理和资源化利用提供科学依据。以生活垃圾为原料,采用7 d翻堆一次的方式,进行为期45 d的堆肥试验。试验设常规和添加5%发酵剂堆肥处理,研究添加外源菌剂对城市生活垃圾堆肥过程中物理和化学特性变化的影响及对堆肥腐熟度的影响。结果显示添加5%菌剂的堆肥处理在堆肥24 h后温度达到53℃,堆肥过程中最高温度达到65℃,温度保持50℃以上达24 d;使堆肥C/N迅速下降,并在35 d后,该值稳定在12.2左右;铵态氮与硝态氮比值开始迅速上升,而后逐渐下降,最终比值稳定在1.2,油菜种子的发芽指数达到85%以上。说明添加5%外源微生物菌剂能加速城市垃圾堆肥腐熟进程。     

低温复合菌剂对牛粪堆肥发酵影响的研究

为了探明低温复合菌剂对牛粪堆肥发酵的影响,开发出适合东北寒区堆肥发酵的微生物菌剂.本研究在0℃以下以牛粪、秸秆为原料,分别设置接种低温复合菌剂堆肥、接种常温菌剂堆肥和自然堆肥3个处理,测定了堆肥过程中温度、p H、C/N、全磷、铵态氮、硝态氮和种子发芽指数的动态变化.试验结果表明,接种低温复合菌剂组第11 d进入高温期(50℃),比接种常温菌剂组提前了14 d,最高温度达62℃,高温期维持了9 d,而自然堆肥组一直未进入高温期.至堆肥结束时,接种低温复合菌剂组和接种常温菌剂组的最终p H分别为7.17、7.24;C/N均降到20以下,分别为16.10、15.67;全磷的变化无明显差异;种子发芽指数分别为92%和85%.添加菌剂组较自然堆肥组铵态氮含量明显降低,硝态氮含量增高.综上所述,接种低温复合菌剂可以在低温下促进堆肥迅速起温,并保证了堆肥的腐熟质量.     

添加剂对厨余垃圾堆肥中H_2S和NH_3排放的影响

以大类粗分后的厨余垃圾为研究对象,玉米秸秆作为调理剂,以不添加菌剂的处理作为对照(CK),以添加腐熟堆肥、鼠李糖脂和固体专用菌剂为3个处理,研究菌剂添加对厨余垃圾堆肥过程中H_2S和NH_3排放的影响。研究结果表明:菌剂添加促进了堆肥腐熟;添加腐熟堆肥更能有效地降低厨余垃圾堆肥过程中H_2S排放,而鼠李糖脂的添加更能有效控制NH_3的排放。从恶臭气体控制、堆肥腐熟并结合H_2S和NH_3的检知嗅阈,优选腐熟堆肥作为厨余垃圾堆肥过程中实现H_2S和NH_3同时减排的添加剂。     

堆肥工艺参数对高氮污泥堆肥氨气产生的影响

为减少堆肥过程中所产生的臭气污染,探讨了高氮污泥堆肥过程中氨气的产生规律及影响因素。改变堆肥原料的C/N比、含水率及温度,观察氨气产生速率及浓度的变化。结果表明:氨气产生速率峰值约出现在第4天,在第15天后基本趋近于0;当碳氮比达到31,初始含水率为55%,环境温度为25℃时,氨气产生速率及浓度较小。     

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.