物理强化复合试剂对污泥中重金属的浸提效果

重金属极大地限制了污泥无害化利用,处置不当将对人类健康及生态环境造成危害。为强化复合试剂对污泥中重金属的浸提率,分别采用超声波和微波两种物理方法进行预处理,并从处理时间、功率和功密度三个角度评价超声波和微波对复合试剂浸提率的影响。结果表明,超声波和微波处理均能提升复合试剂对污泥中Cu、Zn、Mn、Cr和Ni的浸提率。微波预处理的最佳功密度为675 k J/g,此时复合试剂对Cu、Zn、Mn、Cr、Ni的浸提率分别为79%、97%、90%、58%、86%。超声波预处理的最佳功密度为135 k J/g,此时复合试剂对Cu、Zn、Mn、Cr、Ni的浸提率分别为69%、96%、89%、40%、65%。两种物理方法均存在最佳处理时间和功率,实际应用中可根据功密度曲线确定。     

阳极腐蚀对电脱水污泥中重金属的影响

电渗透脱水技术作为一种新型的固液分离技术,对于城市污水厂污泥的深度脱水是非常有效的,但存在严重的阳极腐蚀问题。用原子吸收分光光度法研究了惰性阳极以及5种金属阳极下的污泥电脱水技术对污泥中重金属(Cr、Ni、Zn、Cu、Pb)含量的影响。结果表明,阳极使用惰性材料时,电渗透脱水技术能有效去除一部分重金属,且电压越大越有利于重金属的去除。在金属阳极下,电渗透脱水技术存在不同程度的阳极腐蚀问题,且阳极腐蚀质量与试验次数呈线性相关;阳极使用金属材料时,污泥中的Cr、Ni、Cu含量大幅度增加,Zn、Pb含量略有降低。     

中国城市污泥的重金属含量及其变化趋势

于2006年从全国范围内选取107个城市污泥样品,测定了其重金属含量.结果表明,污泥中As、Cd、Cr、Cu、Hg、Ni、Pb和Zn的平均含量分别为20.2、2.01、93.1、219、2.13、48.7、72.3和1 058 mg/kg.与2001年以前的调查结果相比,污泥中的重金属含量总体呈下降趋势,其中Cd、Cr、Cu、Hg、Ni、Pb和Zn的含量分别降低了32.3%、49.7%、54.9%、25%、37.2%、44.8%和27%.与<城镇污水处理厂污染物排放标准>(GB 18918--2002)相比,城市污泥中Cd、Cu、Ni和Zn含量的超标率相对较高,其超标率分别为6.5%、6.5%、6.5%和11.2%.     

北京市城市污泥土地利用的重金属污染风险评估

重金属污染风险是限制城市污泥土地利用的重要因素,通过调查北京市污泥施用区土壤、作物的重金属含量,评估北京市的城市污泥农用重金属污染风险,筛选北京市城市污泥土地利用优先控制重金属。与对照区相比,北京市城市污泥施用区表层土壤的Hg、Zn和Cu含量分别增加3 731%、86.3%和63.0%,累积趋势较明显。污泥施用区小麦籽粒的Zn含量显著高于对照区,As、Cd、Cr、Cu、Hg、Ni、Pb含量与对照区小麦籽粒的差异并不显著;污泥施用区小麦籽粒的Cu超标率为18.2%,高于对照区的。结合土壤重金属累积特征以及小麦籽粒重金属含量情况,北京市城市污泥土地利用Cu污染风险较大,优先控制的重金属是Cu,其次为Hg。     

生物沥滤法对剩余污泥中重金属及养分含量的影响

以城市剩余污泥为材料,通过对硫酸亚铁(FS)、硫酸亚铁铵(FAS)、单质硫(S0)三种底物的单一和复合投加生物沥滤试验,研究不同类型底物对污泥中重金属及养分含量的影响。结果表明,底物为FAS+S0时污泥中重金属溶出效果最佳,此时对污泥中Cu、Zn、Cr和Ni的去除率分别可达86.7%、88.2%、76.2%和65.0%。沥滤结束时,FAS为底物的污泥中TN、TP含量最高,其次为FS,S0为底物时污泥中TN、TP含量最低,FS+S0和FAS+S0为底物时污泥中TN、TP的含量较单独投加S0时有所提高但不明显,说明S0是导致污泥中TN、TP流失的主要因素。     

污水处理系统耦合水蚯蚓后的重金属迁移转化研究

污水处理系统添加水蚯蚓后处理城市生活污水,研究其对重金属迁移转化的影响。试验结果表明,添加水蚯蚓能促进污泥对重金属As、Cd、Cr、Cu、Ni、Pb、Zn的富集,水蚯蚓自身也吸收一部分重金属,此外还有助于污泥中的重金属由不稳定态向稳定态转化,从而高效去除污水中的重金属。同时,污泥减量达53.8%,且污泥中重金属的浓度增大,稳定态所占比例增加,系统出水水质可稳定达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)的要求。     

复合硫杆菌对污泥重金属生物淋滤机制的影响

对污泥生物淋滤过程中各种重金属元素的形态变化情况进行了测定,借助重金属化学形态转化规律,间接判断污泥重金属生物淋滤的转化机制。试验结果显示,Cu、Ni、Cd的生物淋滤是以直接机制为主的,Zn的生物淋滤过程是以间接机制为主的,Cr、Pb的生物淋滤过程属于混合机制,但其混合机理是有差别的。     

一株氧化硫硫杆菌的分离鉴定及其沥滤污泥研究

从山西某煤矿的酸性矿井水中分离得到嗜酸氧化硫硫杆菌Tt-1,对其形态、生理生化特性、16S rDNA基因序列、生长特性及对城市污泥的沥滤效果进行了研究。Tt-1的菌细胞呈短杆状,革兰氏染色为阴性,不产生芽孢,16S rDNA系统学分析证明其为嗜酸氧化硫硫杆菌。菌株Tt-1的最佳生长条件:温度为28℃,pH值为4.0,接种量为10%,S0浓度为10 g/L。菌株Tt-1在污泥浓度为10%、28℃的条件下沥滤15 d,对污泥中Cd、Cr、Cu、Ni、Pb和Zn的最大去除率分别为66.20%、41.35%、91.74%、65.73%、43.86%和93.72%,处理后污泥中的重金属含量可满足污泥农用标准。     

添加剂对脱水污泥中重金属形态的影响

采用不同添加剂与污水处理厂的脱水污泥进行混合填埋，考察了填埋初期和后期污泥中重金属形态的变化。结果表明，添加生石灰、粉煤灰和粘土均有利于Cr和Cd向稳定形态转化；添加生石灰有利于Pb和Zn向稳定形态转化，而添加粉煤灰和粘土则有相反作用；添加生石灰、粉煤灰和粘土均会促使Cu向不稳定形态转化；添加粉煤灰有利于Ni向稳定形态转化，而添加生石灰和粘土则起到了相反的作用。     

SBR工艺去除城市污泥中重金属的研究

以桂林市某城市污水处理厂二沉池的生污泥为培养介质、以硫酸亚铁为底物,利用简化的SBR工艺对城市污泥中以氧化亚铁硫杆菌为主的沥滤微生物进行驯化培养,研究了沥滤微生物对城市污泥中重金属的去除效果。结果表明，在底物投配比为10g/L、污泥接种量为30%、室温为25℃的条件下连续曝气运行2 d,对Cu和Zn的去除率达78.3%和77.7%，对Cd的去除率接近99%，沥滤处理后污泥中的残余重金属含量符合污泥农用的国家标准。     

An inventory of heavy metals inputs to agricultural soils in England and Wales

An inventory of heavy metal inputs (Zn, Cu, Ni, Pb, Cd, Cr, As and Hg) to agricultural soils in England and Wales in 2000 is presented, accounting for major sources including atmospheric deposition, sewage sludge, livestock manures, inorganic fertilisers and lime, agrochemicals, irrigation water, industrial by-product 'wastes' and composts. Across the whole agricultural land area, atmospheric deposition was the main source of most metals, ranging from 25 to 85% of total inputs. Livestock manures and sewage sludge were also important sources, responsible for an estimated 37-40 and 8-17% of total Zn and Cu inputs, respectively. However, at the individual field scale sewage sludge, livestock manures and industrial wastes could be the major source of many metals where these materials are applied. This work will assist in developing strategies for reducing heavy metal inputs to agricultural land and effectively targeting policies to protect soils from long-term heavy metal accumulation.     

强化化学淋滤对污泥重金属溶出及磷释放的影响

针对采用传统化学淋滤方法处理污水污泥时重金属溶出率低的问题,设计了两种强化化学淋滤方法的对比试验,通过检测重金属形态分布、污泥有机质及磷释放、污泥含固率,研究了强化化学淋滤对污泥各方面综合性能的影响。结果表明:稀硫酸与氯化铁联合处理(处理方法1)对Cu和Cr的溶出效果不明显,但在加入NaNO₂(处理方法2)后使Cu溶出率由7%提升至82%,Zn溶出率由79%提升至88%;同时,两种强化化学淋滤方法均增加了污泥中有机质和磷的释放,污泥中磷含量由23.2 mg/g分别降至12.3 mg/g和10.7 mg/g;与原污泥相比,强化淋滤后的污泥脱水性也均得到了明显改善,其污泥含固率分别提高了52%和61%。     

Total metal concentrations and partitioning of Cd, Cr, Cu, Fe, Ni and Zn in sewage sludge

Application of the BCR three-step sequential extraction procedure to sewage sludge samples collected at an urban wastewater treatment plant (Dom ale, Slovenia) is reported. The total concentrations of Cd, Cr, Cu, Fe, Ni and Zn and their concentrations in fractions after extraction were determined by flame or electrothermal atomic absorption spectrometry (FAAS, ETAAS) under optimised measurement conditions. Total acid digestion including hydrofluoric acid (HF) treatment and aqua regia extraction were compared in order to estimate the efficiency of aqua regia extraction for determination of total metal concentrations in sewage sludge. It was found experimentally that aqua regia quantitatively leached these heavy metals from the sewage sludge and could therefore be applied in analysis of total heavy metal concentrations. The total concentrations of 856 mg kg⁻¹ Cr, 621 mg kg⁻¹ Ni and 2032 mg kg⁻¹ Zn were higher than those set by Slovenian legislation for sludge to be used in agriculture. Total concentrations of 2.78 mg kg⁻¹ Cd, 433 mg kg⁻¹ Cu and 126 mg kg⁻¹ Pb were below those permitted in the relevant legislation. CRM 146R reference material was used to follow the quality of the analytical process. The results of the BCR three-step sequential extraction procedure indicate high Ni and Zn mobility in the sludge analysed. The other heavy metals were primarily in sparingly soluble fractions and hence poorly mobile. Due to the high total Ni concentration and its high mobility the investigated sewage sludge could not be used in agriculture.     

Heavy metal behaviour during the activated sludge process I. Extent of soluble and insoluble metal removal

The extent of removal of Ag, Bi, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Tl and Zn and their distribution between the soluble and insoluble phases in the influent, and effluent of the activated sludge process has been studied using a pilot-scale plant operated at sludge ages of 3, 6, 9 and 12 days. Molybdenum, Tl, Co, Mn and Ni were >50% soluble in the influent settled sewage. The mean removals of the former two metals were <3% and the latter three were 35 and 50%. Silver, Bi, Cd, Cr, Cu, Pb and Zn were all <35% soluble in the influent and had substantial removals of >75%. Solubilities were greater in the effluent than the influent with the exception of Mn. The observed overall removals of Ag, Bi, Co, Ni, Pb, Tl and Zn were almost entirely due to insoluble metal removal; Cd, Cr and Cu removals had a significant contribution from soluble metal removal. Overall Mn removal appeared to be solely due to soluble metal removal.     

Mass balance and distribution of sludge-borne trace elements in a silt loam soil following long-term applications of sewage sludge

Soil samples were collected at 15-cm increments to a depth of 75 cm from plots on a silt loam soil where until several years earlier and for 14 years, anaerobically digested sewage sludge had been annually applied by furrow irrigation. The study protocol consisted of four replications of 6.1 x 12.2-m plots with 0 (T0), 1/4-maximum (T1), 1/2-maximum (T2) and maximum (T3) sludge application rates randomized within blocks. When sludge applications were terminated, maximum sludge-treated plots had received 765 Mg ha-1 (dry weight equivalent) of sludge solids. Total soil concentrations of Cd, Cr, Cu, Ni, Pb and Zn had been significantly enhanced by all sludge application rates to a soil depth of 30 cm. Below the 30-cm depth, total soil Cd was increased to 75 cm, total Zn to 45 cm (T2 and T3 only), total Cr to 60 cm (T2 and T3 only), but total Cu, Pb, and Ni were not increased at depth. Despite the lack of significant increases in subsoil concentrations for some metals, mass balance calculations showed a relatively high proportion of all the above sludge-borne heavy metals to be unaccounted for in the soil profile for each application rate. Mass balance calculations of losses ranged from a high of 60% for Ni to a low of 36% for Cu and Pb. Similar losses were calculated from metal concentrations measured in soil samples taken at the time the sludge was applied. In soil surface samples (0-15 cm) from maximum sludge-treated plots, percentages of total metal concentration extracted with 4.0 M HNO3 ranged from a low of 31 for Zn to a high of 75 for Cu. Efficiency of metal extraction by HNO3 was inconsistent, depending on the soil horizon and sludge treatment, so that evaluation of HNO3-extractable metals is not a reliable method of estimating total metal retention in the profiles. In soil surface samples from maximum sludge-treated plots, the percentage of total metal contents extracted with DTPA ranged from a low of 0.03 for Cr to a high of 59 for Cd. The DTPA extractable levels of Cu, Ni, and Pb were higher in the subsoils of the sludge-treated soils, indicating that these metals had been redistributed from the surface layer to deeper zones in the profile of sludge-amended soil, despite the absence of elevated total concentrations of these three metals in the deeper subsoil.     

电动力修复技术去除城市污泥中的重金属研究

分析了城市污水处理厂污泥中重金属的形态，重点考察了不同形态的Cd、Zn在电动力作用下的去除率。结果表明，污泥经电动力作用5d后，对Cd、Zn的总去除率分别为64．50％、65．02％，其中对易被植物吸收的非稳态（可交换态、碳酸盐结合态和铁锰氧化物结合态）Cd、Zn的去除效果尤为明显，去除率分别高达68．60％、75．73％。可见，应用电动力修复技术去除污泥中的重金属是可行的，修复后的污泥可进行土地利用。     

腐殖土活性污泥中重金属的浸出行为研究

在不同pH值和腐殖土投加量条件下,对活性污泥中Zn、Ni、Cu和Pb四种重金属的浸出行为进行了研究。结果表明,污泥中Zn和Ni的浸出率随pH值的降低而呈明显升高的趋势,Cu和Pb的浸出率也随pH值的降低而升高,但变化幅度相对较小。在酸性条件下,随着腐殖土投量的增加,活性污泥中Zn、Ni、Cu和Pb的浸出率明显降低;而在中性偏碱性条件下,这种变化趋势不明显。投加腐殖土能明显改变活性污泥中重金属的形态分布,促进重金属的稳定化,进而显著改善重金属的浸出行为。     

Seasonal and time variability of heavy metal content and of its chemical forms in sewage sludges from different wastewater treatment plants

Sewage sludges obtained from seven wastewater treatment plants from the province of Salamanca, Spain, were periodically sampled to determine seasonal and time variation of their elemental composition over 2000 to 2002. The aim of this paper was to provide additional insight to evaluate the potential environmental impact following soil incorporation of these materials as amendments. Aqua regia extractable metals (pseudo total content) of Cd, Cr, Cu, Ni, Pb and Zn were determined and furthermore, the main chemical forms of metals within the sludge were evaluated using a five-step fractionation procedure. All the studied sludges displayed high fertility properties due to their richness of OC, P and K. Total mean concentrations of Cd, Cr, Cu, Ni, Pb and Zn in the sludges were within the regulation of the Spanish legislation. Using an multifactor analysis of variance, significant differences between Cr, Cu, Ni, Pb and Zn pseudo total contents (p<0.01) of sludges at different sites were found while the Cd content was statistically similar. Also significant differences were found between these pseudo total contents of heavy metals in samples collected along the time after three years (0.001相似文献   

Bioleaching of heavy metals from sludge after biological treatment of municipal effluent

The article has compared the efficiency of removing heavy metals from the sludge after biological treatment of municipal wastewaters in the course of biological leaching involving heterotrophic and chemotrophic microorganisms and chemical leaching. The article also showed advantages of the bioleaching of metals under conditions of acidogenic heterotrophic metabolism. The efficiency of the leaching of heavy metals from the sludge varies 80% (Zn) to 15% (Cr) and corresponds to the following series: Zn > Mn > Cu > Ni > Cd > Pb > Cr.     

堆肥处理对排水污泥中重金属的钝化作用

讨论了城市排水污泥中重金属的含量和形态分布特征，分析了堆肥处理对污泥中重金属结合形态转化的影响。根据不同学者的研究结果，提出堆肥处理可降低污泥中Zn、Cu、Pb、Mn等重金属的活性，并指出堆肥处理是降低污泥在土地利用中重金属污染风险的途径。