添加生石灰/土、粉煤灰改善污泥填埋特性的研究

为使脱水污泥满足填埋所需要的最低强度要求，分别以生石灰／土、生石灰／粉煤灰为添加剂，对不同添加量下的污泥填埋特性（土工含水率、十字板抗剪强度、无侧限抗压强度）进行了研究。结果表明，生石灰／土对污泥填埋特性的改善效果优于生石灰／粉煤灰的，采用生石灰：土：污泥：1：4：5的配比在养护20d时，试样的十字板抗剪强度〉25kPa、无侧限抗压强度〉50kPa．可达到最低填埋要求。     

掺添加剂改善脱水污泥填埋特性研究

分别以石灰、土、粉煤灰为添加剂,考察了不同添加量时脱水污泥与添加剂混合试样的初始土工含水率、密度、渗透系数、十字板抗剪强度、无侧限抗压强度。结果表明,单纯脱水污泥的强度很低,不能满足填埋要求,而加入添加剂后养护 20~30d就可满足填埋要求。     

微波-碱改性粉煤灰钝化贮存污泥中Cu、Zn的研究

针对国内粉煤灰产量大、贮存污泥量大的现状,开展了利用改性粉煤灰固定贮存污泥中主要重金属的研究。采用"微波-碱"方法对粉煤灰进行改性,利用扫描电镜、红外光谱、X射线衍射、X射线荧光光谱和比表面积测定等手段,对粉煤灰改性前后的物化性质进行分析,并考察其改性后对贮存污泥中Cu和Zn的钝化效果。结果表明,在微波功率为400 W、辐照10 min、NaOH浓度为6 mol/L、浸渍时间为3 h、碱灰比为5:1的条件下,获得的粉煤灰具有最大比表面积,并生成了新的矿物质Ca_2SiO_4,增加了新的表面基团。该改性粉煤灰有利于贮存污泥中的重金属Cu和Zn向稳定态转化,钝化效果优于未改性粉煤灰;当改性粉煤灰的添加量为40%时(扣除干释作用),钝化7 d,污泥中Cu和Zn的各种形态已达到稳定化,且所占比例不随时间的推移而改变。     

污泥与生活垃圾混合填埋产沼的模拟实验研究

通过城市生活垃圾与污水厂脱水污泥的混合填埋模拟实验，研究了添加污泥对垃圾降解及填埋气产生过程的影响，实验结果表明，在填埋垃圾中添加污泥起到了接种微生物的作用，加快了有机垃圾的降解与填埋气的产生，产气速率较生活垃圾直接填埋提高30％以上，填埋气中CH4浓度可达到64％，与没有添加污泥相比，填埋气中CH4含量有较大幅度的提高，有利于填埋气的资源化利用，同时也可为污泥的资源化利用提供经济可行的途径。     

水泥、石灰与粉煤灰对河道淤泥的固化效果研究

衡阳雁西湖疏浚淤泥的含水率较高,为了使其满足填埋的要求,研究了水泥、石灰和粉煤灰的单一或组合固化效果。结果表明,随着固化时间的延长,固化淤泥的含水率降低、无侧限抗压强度(UCS)升高;当采用单一材料时,水泥对淤泥的固化效果显著,而石灰与粉煤灰的固化效果不明显;当水泥为5%、石灰、粉煤灰的掺入量均为2. 5%时,经过7d的养护后,固化淤泥的含水率(52. 7%)及无侧限抗压强度(327. 8kPa)能达到《城镇污水处理厂污泥处置混合填埋用泥质》(GB/T 23485-2009)的污泥混合填埋要求; SEM结果表明,固化淤泥颗粒较原淤泥具有孔隙率小、结构密实、含有大量针状结晶的特点。     

石灰桩加固软弱地基的方法

所谓石灰桩，简单地说，就是在建（构）筑物的软弱地基上，按设计布桩的位置成孔（一般孔径为３００～３５０mm，孔深为４～６m）后，用打碎的生石灰颗粒与活性掺和料（粉煤灰或炉渣），按一定的比例混合，干拌均匀后，分层灌入桩孔内，并分层夯实。这种桩依靠生石灰吸水膨胀达到挤密土壤的效果，加固后的地基质量可靠。石灰桩使用范围较广，适用于粉质粘土、淤泥质粘土和淤泥的加固，并能有效地加固轻粉质粘土和杂填土。但遇有透水良好的砂层和难于成孔的土层，则不宜采用。石灰桩布桩设计，必须依据岩土工程地质报告及基础图进行细致分析…     

改性污泥用作垃圾填埋场日覆盖材料的研究

为了实现污泥的综合利用，提出将其作为垃圾填埋场日覆盖材料的设想，并通过淋雨、剪切等试验测定了污泥本底及经过炉渣或石灰改性后的各项技术指标。结果显示：①不论生污泥还是熟污泥，在未改性之前均不能作为垃圾填埋场的日覆盖材料；②生、熟污泥分别经炉渣、石灰改性后，在较低的混配比例下含水率接近40％、有机质含量〈50％；③当生污泥与炉影石灰混配后的含水率≤40％，熟污泥与炉渣混配后的含水率≤44％、与石灰混配后的含水率≤48％时，渗透系数≥10^-4 cm／s；④熟污泥经过炉渣改性后，所产渗滤液的污染物浓度远低于生污泥的；⑤同种污泥分别与炉渣、石灰进行混配改性后，前者所产渗滤液的COD浓度和pH值小于后者，NH3-N含量则大于后者，但各污染指标值（后者的pH除外）均在垃圾填埋场渗滤液的典型水质范围之内；⑥当生、熟污泥与炉渣混配后的含水率为40％时，其抗剪强度相差甚微，均能够达到垃圾填埋场日覆盖材料的要求。     

污泥干化新技术的特点与应用

污泥碱化稳定技术 1、技术原理 污泥碱化稳定技术原理是使用生石灰稳定污泥，生石灰与水反应生成氢氧化钙．再用少量氨基磺酸与之反应生成氨气。此过程中每公斤石灰可以化合0．32kg水、释放1141kJ的热量，将温度提升到70℃．pH值提升到12．4，从而有效杀灭病原体，并分解有机物．蒸发游离态水0．43kg，而氨基磺酸与石灰反应放出氨气，起到辅助杀菌作用．氨气最后用吸收塔吸收后排放。     

城镇污水厂污泥快速固化剂研究

针对城镇污水厂污泥固化处理周期长、效能低的问题,研发城镇污水厂污泥快速(3d)固化剂。考察了硫铝酸盐水泥、硅酸盐水泥、高锰酸钾、早强减水剂、粉煤灰、石灰等多种固化材料和添加剂对固化体强度的影响。结果表明,随着硫铝酸盐水泥、硅酸盐水泥、高锰酸钾、早强减水剂和粉煤灰掺入量的增加,3 d固化体抗压强度逐步提高,其影响顺序为:硫铝酸盐水泥硅酸盐水泥高锰酸钾早强减水剂粉煤灰;石灰对固化体强度影响显著;膨润土和石膏对增强固化体强度作用较小。快速固化剂组分及其配比为硫铝酸盐水泥(3.9%)、硅酸盐水泥(3%)、石灰(1.7%)、粉煤灰(6%),其3 d固化强度满足污泥填埋处置的要求。固化体浸出液中COD、氨氮浓度显著降低;SEM结果表明,固化污泥颗粒较脱水污泥具有孔隙率小、结构密实、含有大量颗粒状结晶的特点。     

基于响应面法的固化泥浆强度试验研究

试验选用水泥、粉煤灰、生石灰和硅酸钠作为泥浆的固化材料,即以水泥、粉煤灰、生石灰、硅酸钠作为四个影响因子,以28 d的无侧限抗压强度为响应值。采用Box-Behnken响应面试验设计方法安排试验。通过方差分析排除不显著项,建立二次多项式回归方程,并分析各影响因子间的交互关系。结果显示:水泥、生石灰对固化泥浆抗压强度的线性作用显著;粉煤灰在一定掺量条件下可以以1∶1的比例代替水泥对泥浆进行固化。生石灰掺量不宜过高,否则会影响水泥对泥浆的固化作用。生石灰作为粉煤灰的碱性激发剂,对提升粉煤灰的固化作用效果显著。     

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。     

Heavy metal stabilization in contaminated road-derived sediments

There is increasing interest in the stabilization of heavy metals in road-derived sediments (RDS), to enable environmentally responsible reuse applications and circumvent the need for costly landfill disposal. To reduce the mobility of heavy metals (i.e. Cu, Pb and Zn) the effectiveness of amendments using phosphate, compost and fly ash addition were investigated using batch leaching experiments. In general, phosphate amendments of RDS were found to be ineffective at stabilizing heavy metals, despite being used successfully in soils. Phosphate amendment resulted in enhanced concentrations of dissolved organic carbon (DOC), which increased the solubilisation of heavy metals via complexation. Amendment with humified organic matter (compost) successfully stabilized Cu and Pb in high DOC leaching RDS with an optimum loading of 15-20% (w/w). Compost, however, was ineffective at stabilizing Zn. Increasing the pH by amending RDS/compost blends with 2.5-15% (w/w) coal fly ash resulted in the stabilization of Zn, Cu and Pb. However, above a pH of ∼ 7.5 and 8 enhanced leaching of organic matter resulted in an increase in leached Cu and Pb, respectively. Accordingly, the optimum level of fly ash amendment for the RDS/compost blends was estimated to be ca. 10%. Boosted regression trees analysis (BRT) of the data revealed that DOC accounted for 56% and 65% of the Cu and Pb leaching, respectively, whereas pH only accounted for ca. 18% of Cu and Pb leaching. RDS sample characteristics (i.e. metal concentrations, size fractionation and organic matter content) were more important at reconciling the leaching concentrations of copper Cu (27%) than Pb (16%). The most important parameter explaining Zn leaching was pH. Overall, the choice of a suitable stabilization agent/s depends on the composition of RDS with respect to the amount of organic matter present, and the sorption chemistry of the heavy metal of interest.     

Resuspension of coal and coal/municipal sewage sludge combustion generated fine particles for inhalation health effects studies

Airborne particulate matter (PM) is an important environmental issue because of its association with acute respiratory distress in humans, although the specific particle characteristics that cause lung damage have yet to be identified. Particle size, acid aerosols, water-soluble transition metals (e.g. Cu, Fe, V, Ni and Zn), polyaromatic hydrocarbons, and particle composition are the focus of several popular hypotheses addressing respiratory distress. All of the above mentioned characteristics are contained in PM generated from the combustion of both pulverized coal, and biomass, including dried municipal sewage sludge (MSS). In this investigation, we report results from collaborative interdisciplinary research on the inhalation health risks caused by particles emitted from the co-combustion of municipal sewage sludge (MSS) and coal. A solid particle resuspension system was implemented to resuspend ash particles. Mice were exposed to resuspended coal and MSS/coal ash particles. Mice exposed to MSS/coal ash particulate demonstrated significant increases in lung permeability, a marker of the early stages of pathological lung injury, while the mice exposed to coal-only ash did not. These results show that the composition of particles actually inhaled is important in determining lung damage. Zinc was significantly more concentrated in the MSS/coal ash than coal ash particles and the pH of these particles did not differ significantly. Specifically, an MSS/coal mixture, when burned, emits particles that may cause significantly more lung damage than coal alone, and that consequently, the use of MSS as a 'green', CO2-neutral replacement fuel should be carefully considered.     

Bearing ratio and leachate analysis of pond ash stabilized with lime and lime sludge

Recycling of industrial waste is one of the effective ways to overcome their disposal problem. Ash produced by thermal power plants and lime sludge produced by paper mills require huge disposal land and may create environmental problems such as dusting and leaching of harmful heavy metals. Stabilization of the ash can improve its engineering properties and address the environmental problems. This paper reports the laboratory test results of a Class F pond ash stabilized with lime (2%, 4%, 6% and 8% by weight) alone and in combination with lime sludge (5%, 10% and 15% by weight). The X-ray diffraction (XRD) and scanning electron micrograph (SEM) tests were also performed to identify the possible formation of crystalline phases after stabilization. The effects of lime sludge on the unsoaked and soaked bearing ratios of pond ash with different lime contents, after 7 d, 28 d and 45 d of curing, were observed. Test results indicated that the bearing ratio increased considerably up to a 4% lime content which can be taken as the optimum lime content. Further increase in lime content increased bearing ratio gradually but at a slower rate. The effect of lime sludge was more pronounced at the optimum lime content, particularly at a low curing period. Lime sludge improved the bearing ratio in soaked condition significantly. Leachate analysis of stabilized ash was performed using toxicity characteristic leaching procedure (TCLP-1311) method. The concentrations of toxic elements Zn, Cu, Cd, Ni and Cr in the stabilized mixes were lower than those in the unstabilized waste. The results indicated that the pond ash-lime-lime sludge mixes have potential application as road subbase material.     

Element levels in birch and spruce wood ashes: green energy?

Production of wood ash has increased strongly in the last ten years due to the increasing popularity of renewable and CO(2)-neutral heat and energy production via wood burning. Wood ashes are rich in many essential plant nutrients. In addition they are alkaline. The idea of using the waste ash as fertiliser in forests is appealing. However, wood is also known for its ability to strongly enrich certain heavy metals from the underlying soils, e.g. Cd, without any anthropogenic input. Concentrations of 26 chemical elements (Ag, As, Au, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sr, Ti, and Zn) in 40 samples each of birch and spruce wood ashes collected along a 120 km long transect in southern Norway are reported. The observed maximum concentrations are 1.3 wt.% Pb, 4.4 wt.% Zn and 203 mg/kg Cd in birch wood ashes. Wood ashes can thus contain very high heavy metal concentrations. Spreading wood ashes in a forest is a major anthropogenic interference with the natural biogeochemical cycles. As with the use of sewage sludge in agriculture the use of wood ashes in forests clearly needs regulation.     

Treatment of leachate from MSWI bottom ash landfilling with anaerobic sulphate-reducing process

Removal of sulphate and toxic elements from the leachate of a field landfill lysimeter (112m(3)), containing municipal solid waste incineration (MSWI) bottom ash, was studied. The leachate was treated in two parallel laboratory upflow anaerobic sludge blanket (UASB) reactors without and with ethanol as additional carbon source. With ethanol more than 65% of sulphate was removed, while without ethanol removal was negligible. The treatment removed Ba, Ca, Cu, Mn, Mo, Ni, Pb, Tl, Sb, Se, Sr, and Zn of the studied 35 trace and other elements. The sequential extraction of the reactor sludge at the end of runs confirmed that with a few exceptions (Ba, Ca, and Cu) the main mechanism by which the elements were removed was precipitation as sulphides.     

Evaluation of metal concentrations in edible vegetables grown in compost amended soil

Agricultural uses of compost usually have a positive effect on the yield of vegetable crops for human consumption. However, compost that contains heavy metals can transfer these components to soils and plants. To evaluate the contamination levels of metals in soil, compost, and edible vegetables, the Mn, Zn, Pb, Cd, Cu, and Ni total contents were measured. Metal availability in soils, as well as other variables – the pH, CEC (cation exchange capacity), total nitrogen, organic carbon, particle size distribution and mineralogy of the clay fraction – were examined in the soil samples. The analysed compost samples were produced from urban solid waste, cattle manure, and edible vegetable and tree pruning residues. The values of pH, CEC, total nitrogen, organic matter, exchangeable hydrogen and carboxylic groups were measured in the compost samples. Of the six metals examined in the soils, in general, Mn and Zn attained the highest concentrations, followed by Cu. Relatively high Mn, Zn, Cu, Cd and Pb concentrations were found in the soils. Metal concentrations extracted with DTPA were below the critical levels in soils, i.e. the levels above which toxicity is likely. In general, Zn, Pb, Cd, Cu and Ni concentrations in compost were lower than those reported by other workers, while Mn levels were within the range for this metal in compost. The results showed that there was an effect of the vegetable type (p < 0.01) for all the parameters examined. High Pb concentrations were found in lettuce and chive as compared with the tolerance limit for this metal in fresh vegetables in Brazil. Cadmium concentrations were also enhanced in the fresh vegetables compared with the typical concentrations of metals in plants. Zinc, Cu, Cd, and Ni concentrations were lower than the tolerance limits established for foods by the Brazilian legislation.     

粉煤灰粘土粉质粘土膨润土对镍离子吸附试验研究

研究了粉煤灰 、粘土、粉质粘土和膨润土从溶液中去除有毒金属镍离子的吸附过程。动态试验显示吸附过程是快速的。吸附试验结果表明,粉煤灰、膨润土对镍离子的吸附能力远大于粘土和粉质粘土,且粉煤灰大于膨润土。平衡吸附模型充分说明在高浓度下,镍离子在粉煤灰 、粘土、粉质粘土及膨润土上的吸附最符合 Langmuir 等温线, 在粘土和粉质粘土上的吸附也可用线性和 Freundlich 等温线来表示。试验结果还表明:随着吸附剂中镍离子含量的增加,粉煤灰等吸附剂对镍离子吸附的百分数均呈减小的趋势。     

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.