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。     

卧式螺旋式污泥好氧动态堆肥装置的试验研究--含水率对污水厂消化污泥一次发酵的影响

采用自行设计的卧式螺旋式污泥好氧堆肥装置 ,利用间歇式动态工艺 ,以木屑为调理剂 ,对厌氧消化污泥进行了中温堆肥的试验研究。本试验控制物料配比为污泥∶木屑 =10∶1 0 (湿重比 ) ,通气量为 5 0m3 h·t,采用 5组不同的含水率 (5 1 0 %～ 71 0 % )对物料进行一次发酵。研究了含水率对该螺旋式动态堆肥装置的影响 ,重点探讨了含水率与堆体温度、有机物去除和pH、TN、有机C变化的关系 ,确定了该装置的最佳含水率为 5 0 %～ 5 5 % ,并且认为在同等通气条件和物料配比下 ,在一定范围内 ,含水率越高 ,堆体温度越低 ,对有机物的降解也越不利     

通风强度对市政污泥生物干化中试效果的影响

将污泥与树皮按照一定比例混合,利用自主研制的滚筒式污泥生物干化中试系统进行实验,通过对温度、含水率、O2和CO2浓度、挥发性固体(VS)、p H等参数的检测,研究了通风强度对市政污泥生物干化效果的影响.结果表明,通风强度对污泥生物干化有较大影响,通风强度(以VS计)为120 L·(h·kg)-1时,最高温度达到66℃,55℃以上高温可以维持40 h以上,111 h后污泥最终含水率可以降低至56%;生物干化过程中p H始终保持在6.5~8.5之间,不会影响微生物生命活动;滚筒式污泥生物干化反应器能够使反应器内基质均一性良好,对利用滚筒式反应器实现污泥连续流处理提供参考.     

基于土地利用的污泥-餐厨蚯蚓堆肥中碳氮元素的转化特征

我国城市剩余污泥有机物含量低,与厨余垃圾协同处理处置引起广泛关注。以城市污泥和厨余垃圾为堆肥原料,锯末为调理剂,考察二者协同堆肥的工艺性能,探讨基于土地利用为目的的处置途径下碳、氮元素的转化特征。结果表明：在含水率为(73±2)%,温度为(23±1)℃的条件下,蚯蚓能够在剩余污泥和餐厨垃圾中存活和生长并提高堆肥稳定化程度;在为期60 d的堆肥周期后,蚯蚓组的TOC平均降解率为32.62%左右,而对照组的平均降解率为27.13%左右,蚯蚓组的TN增幅为18.90%～29.80%,而对照组为15.83%～27.40%,C/N在堆肥的前后都有所降低,且蚯蚓组的降解率更高;剩余污泥∶餐厨垃圾∶锯末=4∶3∶3(以干重计)堆肥环境下的蚯蚓生长繁殖特征更为优良。市政污泥、餐厨垃圾、锯末联合蚯蚓堆肥处理,可以有效加快堆肥进程,提高有机物的稳定化和资源化利用的程度,利于进行后续土地利用。     

通风策略对污泥生物干化过程中含氮气体和甲烷排放的影响

我国污泥生物干化过程中含氮气体(NH_3、N_2O、NO)排放的数据十分缺乏,尤其是NO,因其化学性质极其活泼,在以往的研究中甚少涉及.本研究以东北某大型污泥生物干化厂的连续流强制通风槽式污泥生物干化为研究对象,通过现场试验,考察不同通风策略下干化效率以及含氮气体、温室气体的排放特征.结果表明,当污泥初始含水率约50%时,采用前期供氧为主、中期温度控制为主、后期以除湿和散热为目的的通风策略,可以明显加快污泥干化速率(试验组在第11 d时的含水率为36.6%,对照组为42%),提升干化效果(最终含水率试验组为33.6%,对照组为37.6%),减少氨气累积排放量5%(试验组氨气累积排放为208 mg·m~(-3),对照组为219.8 mg·m~(-3));同时降低温室气体累积排放当量[试验组每吨干物料的温室气体排放当量(eCO_2)为3.61 kg·t~(-1),对照组为3.73 kg·t~(-1)].但NO累积排放量试验组比对照组高出15.9%(试验组为1.9g·m~(-2),对照组为1.6 g·m~(-2)).     

污泥与秸秆共热解制备生物炭工艺优化及其对Cr(VI)的吸附

在不同热解温度、热解时间及配比下,利用生活污泥与小麦秸秆共热解制备污泥基生物炭(WB),研究了不同条件对WB吸附性能的影响,并以吸附性能为评价指标,应用响应面分析法优化了WB的最佳工艺条件,并研究了最佳WB对水溶液中Cr(VI)的吸附规律。结果表明:1)热解温度、热解时间和配比对WB吸附能力均有显著影响;2)制备WB的最佳热解温度、热解时间、配比分别为503.19℃、120 min、m(麦秆)∶m(污泥)=1.2;3)Langmuir模型和Freundlich模型都能很好地表征WB对Cr(VI)的吸附特征,二级动力学模型可以更好地解释WB对Cr(VI)的吸附机制。     

预加热对柠檬酸脱水污泥冬季生物干化的影响

利用预加热污泥（15℃~30℃）方式进行了柠檬酸脱水污泥冬季生物干化的效果及机理研究.结果表明,脱水污泥预热至20℃时可使生物干化高温期维持5.5d且最高温度可达57℃,干化14d污泥含水率从70%下降至34.80%,同时结合水含量降低了65.58%,远高于其他预热组的44.39%~49.53%的结合水去除率.能量平衡分析结果表明,污泥预热至25℃的生物产热量最高,但预热至20℃时用于水分蒸发的能量利用率最高,占总消耗热量的82.62%.此外,污泥胞外聚合物的蛋白质和多糖分析显示,LB-EPS和TB-EPS中蛋白质与多糖的比值和污泥结合水含量呈正相关,高温期Slime-EPS、LB-EPS、EP-EPS层蛋白质含量显著降低,说明蛋白质降解是柠檬酸脱水污泥生物干化的主要产热与脱水机理.     

谷氨酸与柠檬酸复合去除污泥中重金属及处理后污泥农用可行性分析

采用谷氨酸和柠檬酸按不同比例混合去除消化污泥中重金属,对去除前后污泥的重金属(Cd、Cu、Pb、Zn、Ni)去除率、总氮、总磷、有效氮、有效磷含量进行分析,并与谷氨酸单独作用时进行对比。研究表明:综合考虑重金属去除率以及污泥营养元素的保留,当谷氨酸单独去除污泥重金属时,最佳浓度为0. 4 mol/L。复合去除实验中,0. 4 mol/L谷氨酸与0. 4 mol/L柠檬酸体积比为2∶1时对污泥中Cu、Pb、Zn的去除率最高,分别为5. 60%、3. 34%和53. 94%;体积比为1∶1时次之。当谷氨酸与柠檬酸体积比为2∶1时,重金属去除效果与污泥中营养元素的保留程度较好。谷氨酸与柠檬酸复合作用相比单独使用谷氨酸,对污泥重金属去除率相差不大,但有效营养元素之和高于谷氨酸单独作用,这有利于污泥后续农业资源化利用。     

新疆地区电厂脱硫石膏增强的水泥基污泥固化剂的制备及性能分析

利用水泥基和电厂废弃脱硫石膏研制适用于新疆地区经济高效污泥固化剂,采用单因素多水平和响应面分析的方法研究硅酸盐水泥、脱硫石膏、粉煤灰、过硫酸钾(KPS)的掺比和固化时间对污泥固化体无侧限抗压强度的影响,运用Design-expert优化污泥固化体的无侧限抗压强度,并利用扫描电镜分析污泥固化体的微观结构。实验表明:水泥基和电厂废弃的脱硫石膏能够有效改善污泥固化体的抗压强度;当工程应用中,需要抗压强度最佳时的掺比为m(污泥)∶m(水泥)∶m(脱硫石膏)∶m(粉煤灰)∶m(KPS)=100∶3∶1∶1∶0. 5、固化时间为3 d;而需要经济最优时的掺比为m(污泥)∶m(水泥)∶m(脱硫石膏)=100∶1∶1、固化时间为7 d,处理每吨污泥的药剂成本为5～6元。     

污泥与稻秆共热解对生物炭中碳氮固定的协同作用

为了研究共热解对生物炭中碳氮固定的协同效应,利用管式固定炉开展了不同热解温度(300~700℃)下的污泥与稻秆单独热解及其共热解(泥秆质量分别为1∶3、1∶1、3∶1)试验研究.结果发现,污泥和稻秆共热解并不是两种物料单独热解贡献的简单叠加.共热解对生物炭产率无协同效应,但对固定碳产率的协同性受共热解条件影响较大.在相同热解温度下,1∶3和3∶1泥秆比共热解生物炭中的碳和氮含量协同量化值均明显大于1∶1泥秆比下的协同量化值,碳和氮元素含量协同量化值分别在热解温度和泥秆比为(400℃、1∶3)与(400℃、3∶1)时达到最大值12.43%与40.65%.碳和氮固定率协同量化值随热解温度的升高而增加,最大分别为53.77%~56.13%和38.30%~39.12%,说明共热解可显著提高生物炭中碳和氮元素的固定水平.除3∶1泥秆比共热解生物炭中H/C原子比大于理论值,对降低生物炭的芳香度与饱和度具协同作用外,其他共热解条件下的H/C、(O+N)/C、O/C原子比均小于理论值,对提高生物炭的稳定性具明显的协同促进作用.污泥与稻秆在泥秆比1∶3、1∶1与3∶1下共热解,提高协同效应的方式分别为促进脱氧去氢反应、去氢反应与脱氧反应.该研究结果可为生物炭在碳氮封存减排中的应用提供新的工艺途径.     

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.     

Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa and mustard in hydroponic culture

Soil contaminated with heavy metals cadmium(Cd)and lead(Pb)is hard to be remediated.Phytoremediation may be a feasible method to remove toxic metals from soil,but there are few suitable plants which can hyperaccumulate metals.In this study,Cd and Pb accumulation by four plants including sunflower(Helianthus annuus L.),mustard(Brassica juncea L.),alfalfa(Medicago sativa L.), ricinus(Ricinus communis L.)in hydroponic cultures was compared.Results showed that these plants could phytocxtract heavy metals, the ability of accumulation differed with species,concentrations and categories of heavy metals.Values of BCF(bioconcentration factor)and TF(translocation factor)indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals.Changes on the biomass of plants,pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures.Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals,such as pH and Eh regulations,and so forth.     

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.