超声-生物沥浸-氧化钙联合超高压压滤系统实现市政污泥深度脱水及其泥饼的毒性评估

本研究采用超声-生物沥浸-氧化钙调理联合超高压压滤系统对市政污泥进行深度脱水试验,探讨了其调理过程对污泥脱水效率的影响,并对调理后的脱水污泥的重金属含量及植物毒性进行评估.结果表明,经超声-生物沥浸-氧化钙调理后,比阻(SRF)去除率和结合水去除率分别达到90.12%和72.21%.经预调理联合超高压压滤系统处理后,泥饼含水率降低至49.94%,泥饼中Cr、Cu、Cd、 Zn、As和Pb的去除率分别为42.41%、36.50%、30.92%、27.97%、25.94%、22.11%,白菜发芽指数大于80%.通过分析污泥理化性质及滤液有机物含量,阐明该联合技术的作用机理.首先,超声预处理后,污泥结构被破坏,造成污泥粒径d_0.5减小、zeta电位上升,污泥中多糖和蛋白质被释放,从而改善脱水性能,促进污泥中重金属释放,植物毒性降低;经超声-生物沥浸调理后,污泥粒径d_0.5进一步减小、zeta电位趋近于中性,滤液中酪氨酸/色氨酸类氨基酸类有机物和酪氨酸/色氨酸类蛋白有机物被降解且疏水性的腐殖酸和富里酸类有机物含量升高,污泥脱水性能进一步提高,泥饼重金...     

荷电喷雾脱硫实验与机理分析

对湿法烟气脱硫系统引入静电效应后产生的脱硫增益作用进行了实验测定，清水水雾和石灰液浆滴荷电前后的脱硫效率比较实验结果表明，对于中等SO2浓度，这种效应可使雾滴或浆滴脱硫效率增加8个百分点左右，理论分析指出，荷电对强化烟气脱硫是有益的，雾滴或浆滴带电后本质上提高了雾滴的表面活性，改善了脱硫通道中雾滴的弥散程度，从而加速了SO2的吸收进程。     

Study on the influence of additives in an industrial calcium fluoride and waterworks sludge co-melting system

This work explores the effect of additives on the pouring temperature in a waterworks and industrial calcium fluoride sludge co-melting system. Two kinds of sludge were mixed in various ratios to find a mixing ratio at which the operating temperature for subsequent additive tests was relatively low. Various proportions of either sodium carbonate (Na2CO3) or potassium carbonate (K2CO3) reagent were added to the mixed-sludge samples to elucidate the consequent changes in pouring temperature. The experimental results revealed that the pouring temperature was lowest when calcium fluoride was mixed with waterworks sludge in a ratio of 4:6 (w/w). Adding sodium carbonate or potassium carbonate reagent to the mixed-sludge samples further reduced the pouring temperature. Increasing the amount of sodium carbonate did not significantly reduce the pouring temperature beyond that observed when 2% was added, suggesting that 2% was the optimal additional percentage of sodium carbonate. In contrast, the pouring temperature was increased when over 2% potassium carbonate was added to the mixed-sludge samples, revealing that the optimal additional percentage of potassium carbonate was also 2%. These findings indicate that both sodium carbonate and potassium carbonate can be used as additives to increase the energy efficiency of the melting process, but sodium carbonate is more operationally convenient.     

Effects of Acidification and its Mitigation with Lime and Wood Ash on Forest Soil Processes in Southern Sweden. A Joint Multidisciplinary Study

A joint multidisciplinary investigation was undertaken to studythe effects of lime and wood ash applications on two Norway spruce forest Spodosolic soils. The two sites, typical for southern Sweden, were treated in 1994 with either 3.25 t ha^-1 dolomite or 4.28 t ha^-1 wood ash (Horröd site) or in 1984 with either 3.45 or 8.75 t ha^-1 dolomite (Hasslöv site). Both sites show signs of acidification by atmospheric anthropogenic deposition and possessed low soil pH(4.3) and high concentrations of inorganic Al (35 M) in theupper illuvial soil solution. The prevailing soil conditions indicated perturbed soil processes. Following treatment with lime or wood ash, the soil conditions were dramatically altered. Cation exchange capacity (CEC) and base saturation (BS) was considerable increased after addition. Four years after application most of the added Ca and Mg was still present in the mor layer. Fifteen years after application,Mg in particular, became integrated deeper in the soil profile with a greater proportion lost by leaching incomparison to Ca. The concentrations of these ions were greatestin the mor layer soil solutions and Mg had higher mobility givinghigher concentrations also deeper in the profile. Four years after treatment, the application of wood ash and limeresulted in lower pH values and higher inorganic Al in mineral subsoil solutions compared to the untreated soil. We hypothesize that this was probably due to an increased flow of hydrogen ionsfrom the upper soil as a result of displacement by Ca and Mg ionsin the enlarged exchangeable pool. In contrast, fifteen years after lime and wood ash application, the mineral subsoil horizonspossessed a higher pH and lower soil solution Al content than theuntreated plots.Liming promoted soil microbial activity increasing soil respiration 10 to 36%. This is in the same range as net carbon exchange for forests in northern Sweden and could potentially have a climatological impact. The turnover of low molecularweight organic acids (LMWOA) by the soil microbial biomass werecalculated to contribute 6 to 20% to this CO₂ evolution.At Horröd, citrate and fumarate were the predominant LMWOAs with lowest concentrations found in the treated areas. In contrast, at the Hasslöv site, propionate and malonate were the most abundant LMWOAs. Higher microbial activity in the upper soil horizons was also theprobable cause of the considerably higher DOC concentrations observed in the soil solution of ash and lime treated areas. Thelime-induced increase in DOC levels at Hasslöv could be attributed to increases in the 3–10 kDa hydrophobic size fraction. Liming also promoted nitrification with high liming doses leading to extreme concentrations of NO₃ ^- (1 mM) in soil solution.At Hasslöv the community of mycorrhizal fungi was dramatically changed by the addition of lime, with only four of 24 species recorded being common to both control and treated areas.Many of the observed effects of lime and ash treatment can be viewed as negative in terms of forest sustainability. After fouryears of treatment, there was a decrease in the pH of the soil solution and higher concentrations of inorganic Al and DOC. Increased organic matter turnover, nitrification and NO₃ ^-leakage were found at Hasslöv. Considering that the weathering rate and the mineral nutrient uptake by trees is mostprobably governed by mycorrhizal hyphae etchingmineral grains in the soil, it is important to maintain this ability of the mycorrhizal fungi. The lime and ash-induced changed mycorrhizal community structure may significantly affect this capability. In light of this investigation and others, as reviewed by Lundström et al. (2003), the implications ofliming on forest health are multifaceted with complex relationships occurring over both space and time.     

Alteration of shell nacre micromorphology in blue mussel Mytilus edulis after exposure to free-ionic silver and silver nanoparticles

This study describes the morphology of inner shell surface (ISS) of the blue mussel Mytilus edulis Linnaeus after short-term exposures to radiolabeled silver in free-ionic (^110mAg⁺) and engineered nanoparticulate (^110mAgNPs, <40 nm) phases. Radiolabeled silver in starting solutions was used in a similar low concentration (∼15 Bq mL⁻¹) for both treatments. After exposure experiments radiolabeled silver was leached from the ISS using HCl. It concentration for shells from both treatments was ∼0.5 Bq mL⁻¹. Whole ISS of young individuals and prismatic layer of adults showed no evidence of any major alteration process after silver uptake. However, the nacre portion of adult mussels exposed to both treatments revealed distinct doughnut shape structures (DSS) formed by calcium carbonate micrograins that covered the surface of aragonite tablets. Scanning electron microscope (SEM) imaging revealed the existence of only minor differences in DSS morphology between mussels exposed to Ag⁺ and AgNPs. From literature survey, DSS were also found in bivalves exposed to Cd²⁺. The DSS occurring in a specimen of a field-collected bivalve is also shown. Formation of distinctive DSS can be explained by a disturbance of the shell calcification mechanism. Although the occurrence of DSS is not exclusively associated with metal bioavailability to the mussels, the morphology of DSS seems to be linked to the speciation of the metal used in the uptake experiments.     

污泥与生活垃圾混合填埋对渗滤液导排系统堵塞的影响

污泥经预处理达到入场标准后与生活垃圾混合填埋是我国现阶段污泥处理的主要方式。由于污泥与生活垃圾特性差异较大,会影响渗滤液物理、化学、生物特性,进而对填埋场渗滤液导排系统产生不利影响。通过柱实验对比了污泥与生活垃圾混填前后产生的渗滤液水质变化,结果表明：污泥与生活垃圾混填后渗滤液中颗粒物浓度及大颗粒物占比均有显著提升;采用生石灰对污泥预处理提高了污泥自身有机质（VFAs等）的释放速率;8%的生石灰预处理污泥（10%混合比例）掺加量会提高生活垃圾产生的渗滤液中Ca2+浓度31.6%。通过分析可知,结合填埋场导排系统堵塞的影响因素有微细颗粒物沉淀、微生物膜生长及钙基化合物沉积,从减缓填埋场导排系统堵塞、延长填埋场使用年限的角度出发,污泥宜单独分区填埋,生石灰预处理污泥不宜与生活垃圾混填。     

石灰海泡石钝化后两种轮作模式对重度镉污染农田土壤的利用及修复

为安全利用并修复矿区重度镉污染农田,使作物达到饲料安全标准,以不同配比的石灰海泡石作为钝化剂,钝化后试验两种轮作模式（玉米-紫花苜蓿和玉米-黑麦草）,综合分析比较,筛选出最佳的钝化剂配比及配套的轮作模式.进行大田试验,测定土壤理化性质、重金属Cd有效态含量及作物中Cd含量、生物量,并采用BCR形态分级试验研究土壤钝化前后重金属形态的变化,综合分析评价其修复效果.结果表明：（1）通过石灰海泡石的施加,能不同程度地提高土壤pH值、有机质和CEC.（2）推荐施加量为LS1(石灰6.6 t·hm^-2+海泡石9.9 t·hm^-2),相比CK可显著降低玉米根、茎、叶和籽粒中重金属Cd的含量,分别降低了70.27%、 61.54%、 46.51%和44.23%.紫花苜蓿地上部Cd显著下降了78.47%,而黑麦草地上部Cd显著下降了65.79%.玉米季、紫花苜蓿种植区和黑麦草种植区土壤有效态Cd钝化率分别为51.37%、 69.58%和77.83%,土壤中重金属由活性高的弱酸提取态向活性低的残渣态进行转化.（3）推荐在施加量为LS1下,配合玉米-紫花苜蓿的轮...     

施肥模式对砂姜黑土区土壤种子库影响的研究

通过对砂浆黑土区小麦-大豆轮作制地不同施肥模式的杂草土壤种子库（0～15 cm）进行调查,分析种子库的大小、组成、多样性等特征,探讨施肥模式与群落演替速率之间的关系。结果表明,施肥模式显著影响着土壤种子库的大小、组成、多样性、群落演替速率。土壤样品中共检出杂草种子18种,隶属于11科,且各处理优势种组成差异明显。种子库密度按NPK〉NP〉NK〉CK〉PK顺序依次递减且差异极显著（P〈0.01）。各处理物种组成不同,种数按CK〉NPK〉PK=NK〉NP顺序依次递减,群落均匀度指数按NP〉CK〉NK〉PK〉NPK顺序依次递减且差异显著（P〈0.05）,物种多样性指数按CK〉NP〉NK〉PK〉NPK顺序依次递减,群落优势度指数按NPK〉PK=NK〉CK〉NP顺序依次递减。我们初步认为适应与竞争机制影响土壤种子库的物种组成、密度的差异;施肥模式间土壤种子库的优势种变化尤为突出,引起均匀度的改变,导致施肥模式下土壤种子库多样性的差异。Whittaker指数按CK〈NPK〈PK=NK〈NP顺序依次增大,表明土壤种子库的群落演替速率依次加快,说明长期平衡施肥模式（NPK）对土壤种子库群落的影响明显小于PK、NP、NK施肥处理,群落结构较PK、NP、NK施肥处理更稳定。气候、取样时间、除草剂等因素导致年际间、种植季间的杂草土壤种子库特征差异明显。本研究认为长期平衡施肥既有利于作物的优质高产,也有利于农田土壤种子库群落的稳定,是建立合理、高效、稳定的农业生态系统以及取得良好的经济效益和生态效益的重要施肥方式。     

广西刁江流域Cd和Pb复合污染稻田土壤的钝化修复

采用田间小区试验,研究施用海泡石、石灰和磷酸盐对广西刁江流域Cd和Pb复合污染稻田土壤的钝化修复效应,并通过土壤重金属形态分析探讨不同钝化剂的作用机理。结果表明,添加钝化剂可显著提高稻谷和秸秆产量,最大增产率分别可达25．4％和28．3％,其中海泡石与磷酸盐复配处理增产效果最佳。施用钝化剂可以有效降低水稻各部位重金属含量,水稻糙米Cd和Pb含量最大降幅可达65．12％和61．86％;钝化剂复配处理对水稻地上部Cd和Pb含量的降低效果明显优于单一处理,其中海泡石和磷酸盐或石灰复配处理糙米cd含量符合GB2762--2005《食品中污染物限量》。不同钝化处理均能显著降低土壤TCLP（毒性特性浸出程序）提取态cd和Pb含量,最大降幅分别为28．86％和45．60％,其中钝化剂复配处理对土壤TCLP提取态重金属的抑制效果优于单一钝化处理。总体而言,海泡石与磷酸盐复配处理对广西刁江流域重金属复合污染稻田土壤的钝化修复作用最佳。     

疏水改性石灰对土壤中高浓度硝基苯的强化固定

石灰是一种常见的应用于污染土壤固化稳定化的水硬性胶结材料,但对于紧急事故情况下释放到土壤中的高浓度毒性有机物的固定能力十分有限.为了增强石灰对于毒性有机物的定向捕获的固定能力,本研究用硬脂酸对石灰进行疏水改性,并通过分散性实验、粒度测试、扫描电镜测试、红外光谱测试和接触角测试对改性前后的石灰进行表征.然后用改性石灰对硝基苯含量为8163 mg·kg~(-1)的污染土壤进行固化稳定化实验,测试在固化稳定化过程中硝基苯的挥发率和浸出率.结果表明,与不添加石灰的空白组和只添加30%未改性石灰的对照组相比,添加20%的改性石灰和10%的未改性石灰,可分别减少94.44%和88.46%的硝基苯挥发量,99.10%和88.11%的酸浸出条件下的硝基苯浸出量,及98.51%和59.74%的水浸出条件下的硝基苯浸出量.经硬脂酸疏水改性后的石灰可作为定向捕获快速固定土壤中高浓度毒性有机物的固化剂.