Ambient air temperature Effects on the temperature of sewage sludge composting process

Using data obtained with a full-scale sewage sludge composting facility, this paper studied the effects of ambient air temperature on the composting temperature with varying volume ratios of sewage sludge and recycled compost to bulking agent. Two volume ratios were examined experimentally, 1 ： 0 ： 1 and 3 ： 1 ： 2. The results show that composting temperature was influenced by ambient air temperature and the influence was more significant when composting was in the temperature rising process： composting temperature changed 2.4-6.5℃ when ambient air temperature changed 13℃. On the other hand, the influence was not significant when composting was in the high-temperature and/or temperature falling process： composting temperature changed 0.75-1.3℃ when ambient air temperature changed 8-15℃. Hysteresis effect was observed in composting temperature＇s responses to ambient air temperature. When the ventilation capability of pile was excellent（at a volume ratio of 1：0：1）, the hysteresis time was short and ranging 1.1-1.2 h. On the contrary, when the proportion of added bulking agent was low, therefore less porosity in the substrate（at a volume ratio of 3：1：2）, the hysteresis time was IonQ and ranging 1.9-3.1 h.     

污泥热处理过程中多环芳烃和多氯联苯的迁移行为

对污泥热处理过程中产生的多环芳烃、多氯联苯等有机污染物的迁移转化行为及条件进行了模拟实验研究.结果表明,污泥中多环芳烃中的萘、荧蒽、苯并(b)荧蒽、苯并(a)芘、茚并(1,2,3-cd)芘在 800℃温度条件下的去除率分别为66.28%,73.7%,100%,30.7%和100%;多氯联苯在300~400℃之间含量急剧减少,1000℃时其单体PCB28、PCB52、PCB101、PCB118、PCB153、PCB138和PCB180的去除率分别为89.35%、90.66%、89.43%、93.97%、99.1%、84.7%和95.22%. 2种物质迁移规律与处理体系温度变化直接相关,2种物质从污泥中转化释放的温度条件分别为:多环芳烃300~750℃(90%以上),多氯联苯350~900℃(85%以上).处理过程中2种污染物的不同单体间存在复杂的转化反应.     

CaO2促进MFC同步处理剩余污泥和六价铬废水的效能

为了提高剩余污泥降解效能和废水中六价铬还原效能,研究了CaO₂对微生物燃料电池同步处理剩余污泥和六价铬废水的影响,考察了不同CaO₂投加量下微生物燃料电池阳极剩余污泥的降解效能、阴极六价铬的还原效能及产电效能.结果表明,当阳极室CaO₂投加量分别为0,0.1,0.2,0.4,0.6,0.8gCaO₂/gVSS时,运行120h后,阴极六价铬还原率分别为73.38%,78.91%,99.47%,97.70%,97.04%,96.37%,运行30d后,阳极剩余污泥TCOD降解率分别为72.4%,76.9%,81.0%,78.2%,75.7%,74.2%.证明投加CaO₂后,六价铬还原率和TCOD降解率都有提高.当投加量为0.2gCaO₂/gVSS时处理效能最好,输出电压最大为1.15V.六价铬还原率提高了36.08%,TCOD降解率提高了11.88%.此外,投加CaO₂后微生物燃料电池电化学活性有所提高,表明CaO₂投加对电池电子传递过程有促进作用.结果说明CaO₂有利于提高对微生物燃料电池同步处理剩余污泥和六价铬废水效能.     

Effects of thermally pretreated temperature on bio-hydrogen production from sewage sludge

Hydrogen can be obtained by anaerobic fermentation of sewage sludge. Therefore, in this paper the effects of thermally pretreated temperatures on hydrogen production from sewage sludge were investigated under different pre-treatment conditions. In the thermal pretreatment, some microbial matters of sludge were converted into soluble matters from insoluble ones. As a result, the suspended solid（SS） and volatile suspended solid（VSS） of sludge decreased and the concentration of soluble COD（SCOD） increased, including soluble carbohydrates and proteins. The experimental results showed that all of those pretreated sludge could produce hydrogen by anaerobic fermentation and the hydrogen yields under the temperatures of 121℃ and 50℃ were 12.23 ml/g VS（most） and 1.17 ml/g VS （least）, respectively. It illuminated that the hydrogen yield of sludge was affected by the thermally pretreated temperatures. Additionally, the endurance of high hydrogen yield depended on the translation of microbial matters and inhibition of methanogens in the sludge. The temperatures of 100℃ and 121℃ （treated time, 30 min） could kill or inhibit completely the methanogens while the others could not. To produce hydrogen and save energy, 100℃ was chosen as the optimal temperature for thermal pretrcatment. The composition changes in liquid phase in the fermentation process were also discussed. The SCOD of sludge increased, which was affected by the pretreatment temperature. The production of volatile fatty acids in the anaerobic fermentation increased with the pretreatment temperature.     

Plants grown on sewage sludge in South China and its relevance to sludge stabilization and metal removal

The production of sewage sludge in China has been increasing sharply in order to treat 40% of the municipal sewage in 2005 as planned by central government. The main sludge disposal method is landfill owing to heavy metal contamination, but it presents an attractive potential for agricultural land application. Experiments were carried out to study the simultaneous metal removal and sludge stabilization byplants. The sludge samples were collected from Datansha Wastewater Treatment Plant of Guangzhou, it contained excessive Cu and Zn comparedwith the Chinese National Standard for Agricultural Use of Sewage Sludge. Plants growing on sludge beds were investigated to follow their growthand metal uptake. 30 sludge plants were identified during 1 year‘s observation. A Zn high-accumulating and high growth rate plant( A/ocas/amacrorrhiza) was selected and grown on sludge beds in plots. The water, organic matter, heavy metals and nutrients contents, the E. colinumber and the cress seed germination index were monitored for the slu,ge samples collected monthly. The plant growth pparameters and its heavy metals contents were also determined. The sewage sludge treated by plants could be stabilized at about 5 months, the E. coli numberwas significantly decreased and the cress seed germination index attained 100%. Crop on sludge could ameliorate the sludge drying. Theexperiments are continuing to find out the appropriate plant combination for simultaneous sludge stabilization and metal removal for an acceptableperiod. Comparisons between the proposed processes and other methods for treating produced sludge such as composting, chemical and bacterial.     

温度对蚯蚓处理城镇污泥稳定化过程的影响

在蚯蚓堆肥过程中,温度会对微生物和蚯蚓活性产生影响,进而影响堆肥效率.将城镇脱水污泥制成5 mm的颗粒,通过比较3个温度条件下(15、20、25℃)赤子爱胜蚓(Eisenia foetida)处理城镇污泥过程中理化、生化指标的变化,研究温度对蚯蚓堆肥稳定化过程的影响.结果显示,在整个稳定化过程中,随温度升高,有机质(OM)、微生物量碳(MBC)降低,电导率(EC)、NH_4~+-N、NO_3~--N升高,而脱氢酶活性(DHA)随温度变化不具有明显规律性.主成分分析(PCA)结果表明,蚯蚓堆肥稳定化过程依次经历以有机质生物降解、氨化和硝化为特征的3个阶段.以蚯蚓适宜生长温度控制蚯蚓堆肥,将更有利于蚯蚓与微生物协同作用的高效发挥.温度能改变蚯蚓堆肥的稳定化效率,但并不改变稳定化路径.     

白线蚓对蚯蚓处理城市污泥的影响

蚯蚓处理污泥反应器中,常伴大量的白色线蚓(寡毛纲、线蚓科).因此,本文以蚯蚓处理城市污泥为研究对象,初步探讨了白线蚓(Enchytraeus Spp.)接种密度对赤子爱胜蚓(Eisena fetida)处理城市污泥的影响.结果表明,白线蚓的密度显著影响了蚯蚓堆肥后产物的物理化学性质和蚯蚓的生物量.白线蚓接种密度与蚯蚓堆肥产物的pH值、电导率(EC)、总氮(TN)呈负相关;与其总有机碳(TOC)、有效磷(AP)、重金属Cu、Zn、Pb、Cr及Cd的含量呈正相关.同时较高的白线蚓接种密度显著降低了蚯蚓的生长率,但蚯蚓的卵数未受显著影响.由此可知,蚯蚓和白线蚓在反应器中存在食物链竞争关系.本研究建议对蚯蚓处理污泥反应器中的白线蚓采取一定的控制措施.     

矿山生态修复及市政污泥稳定化产物应用潜力

对矿山土地的破坏、污染与危害进行了调研和回顾,详细介绍了矿山土地的物理修复、化学修复和植物修复技术,以及含硫矿山所特需的酸性矿山废水（AMD）原位阻断技术,分析其优缺点及使用条件.研究得出矿山土地生态修复技术的选择依据,通过一系列技术阻断污染,修复与改良表层土壤后建立植被,最终实现生态修复.指出提供足够的、符合需求的植物生长基质是矿山土地生态系统修复的关键要素.进一步提出符合标准要求的市政污泥稳定化产物具有替换客土、预防AMD产生、阻断矿山重金属污染、为矿山土地补充维持植物生长所必需的养分、强化矿山土地保水保肥的作用.同时,对于我国目前待修复的矿山面积,市政污泥稳定化产物施用在时间维度上具有长期的可持续性.因此,市政污泥稳定化产物在矿山土地生态修复的应用上具有潜力和优势.     

不同玉米品种对新鲜城市污泥处理效果的初步研究

寻求城市污泥安全农用的方法是当前城市污泥处理处置的重要研究课题之一.采用小区试验,研究了8个玉米品种对新鲜城市污泥处理效果.结果表明:所选择的8个玉米品种均可以在污泥上生长,大丰5品种对锌的累积量最低,04杂1品种对镉累积量最低,会单4品种对铜和铅累积量最低;玉米种植可显著降低城市污泥中的含水率,比不种玉米的对照处理(69.43%)水分去除率提高9.05%~17.50%,有利于城市污泥的干化及后续利用;各玉米品种植株中的总养分(氮+五氧化二磷+氧化钾)均高于有机肥标准(NY525—2012)的总养分要求,而重金属镉和铅的质量浓度除赛田3品种外其他品种均低于农用有机肥标准(NY525—2012)的限量值;玉米种植后城市污泥中的总养分和锌、镉、铜、铅4种重金属质量浓度变化很小.可见,利用玉米处理新鲜的城市污泥既可降低城市污泥中的水分,又可以产生一定量优质的有机肥原料,为城市污泥的资源化利用提供新思路.     

碱热联合破解污泥效果及动力学研究

研究了碱热联合处理对污泥的破解效果并进行了动力学分析.结果表明,碱的加入显著提高了热处理的破解效果,NaOH的破解效果比Ca(OH)2好.碱热联合处理脱水泥饼的适宜处理参数为140℃、90min、Ca(OH)2和NaOH投加量为0.25g/g总固体(TS).在该条件下,溶解性化学需氧量(SCOD)比未加碱时分别增加了41.26%和198%,质量减少率分别为50%、57%.采用NaOH碱热破解污泥后的SCOD值与热处理温度(T)、处理时间(t)及投碱量(A)的关系可以用幂指数模型表示:SCODNa=10178.17[T ]0.43 [A ]0.59t 0.24.     

高温热水解对高含固污泥中磷的形态转化影响

通过正交实验、单因素温度影响实验,利用SMT磷分级提取法研究了高温热水解后高含固污泥中磷的形态转化.结果表明,120℃~160℃的高温热水解可以将高含固污泥中14.80%以上的有机磷转化为无机磷,影响因素对无机磷/总磷的影响大小顺序为：热水解温度 > 热水解时间 > 氧化剂含量 > pH值,随着温度的升高,高含固污泥中无机磷/总磷也从79.13%增加至95.87%;当热水解温度为160℃、时间为40min时,高含固污泥中无机磷含量由原泥的18.30mg/g增至20.49mg/g,无机磷/总磷由80.83%增至96.97%.结果为实现污泥中磷的回收利用奠定基础,同时为“高温热水解+高含固厌氧消化”工艺的优化提供新思路.     

热碱处理对污水处理厂污泥特性的影响研究

热碱处理是一种重要的污泥预处理方法.选取污泥浓度、p H、温度和处理时间这4个因素,采用正交试验,研究了这些因素对污水处理厂污泥融胞、污泥浓度及污泥形态等污泥特性的影响,以对污泥热碱处理的条件进行优化.结果表明,这4个因素对污泥融胞、污泥浓度和污泥形态特征影响的显著性均为:p H温度时间污泥浓度.此外,这4个因素对释放单位污泥溶解性化学需氧量(SCOD)和减小污泥浓度的最佳组合条件为:污泥浓度36.55 g·L-1、p H 12.45、温度175℃和处理时间60 min,而对减小污泥粒径和分形维数的最佳组合条件为:污泥浓度36.55 g·L-1、p H 12.5、温度175℃和处理时间45 min.     

Waste activated sludge hydrolysis and acidification: A comparison between sodium hydroxide and steel slag addition

Alkaline treatment with steel slag and NaOH addition were investigated under different pH conditions for the fermentation of waste activated sludge. Better performance was achieved in steel slag addition scenarios for both sludge hydrolysis and acidification. More solubilization of organic matters and much production of higher VFA (volatile fatty acid) in a shorter time can be achieved at pH 10 when adjusted by steel slag. Higher enzyme activities were also observed in steel slag addition scenarios under the same pH conditions. Phosphorus concentration in the supernatant increased with fermentation time and pH in NaOH addition scenarios, while in contrast most phosphorus was released and captured by steel slag simultaneously in steel slag addition scenarios. These results suggest that steel slag can be used as a substitute for NaOH in sludge alkaline treatment.     

花生壳掺烧对市政污泥燃烧性能的影响

针对花生壳掺混对市政污泥燃烧性能的影响及污染气体的排放,分析了升温速率和花生壳掺混比例对燃烧过程的影响规律.结果表明,当花生壳掺混比例为40%时,升温速率从5℃/min增加到30℃/min,样品的综合燃烧性能指数增大6.9倍,挥发分释放特性指数增大4.5倍;当升温速率为30℃/min时,花生壳掺混比例从0%到40%,样品的综合燃烧性能指数增大1.7倍,挥发分释放特性指数增大5.6倍;因此花生壳的掺混能有效改善污泥的燃烧性能.非等温动力学拟合结果显示,随着花生壳掺混比例增大,样品的反应活化能从87.16kJ/mol下降到69.73kJ/mol,更有利于反应进行.污染气体实时监测结果显示,花生壳掺混比例从10%增加到40%,样品的NO排放峰值下降了60%,说明花生壳的掺入能够显著减少样品燃烧时污染气体的排放量.     

不同溶剂和反应温度对污泥热液化制取生物质油性质影响研究

选取4种溶剂(水、乙醇、正己烷、水-乙醇共溶济)作为污泥热液化制取生物质油的溶剂,分析溶剂种类和反应温度对热液化效果和生物质油性质的影响.结果表明:相同温度下,生物质油产率随溶剂种类变化趋势为:乙醇水-乙醇共溶剂正己烷水,最高产率为54.82%(乙醇溶剂,240℃).污泥有机物转化率随溶剂种类变化趋势为:水-乙醇共溶剂乙醇水正己烷,最高有机物转化率为96.40%(水-乙醇共溶剂,330℃).污泥经热液化处理后,碳、氢、氮、硫元素在生物质油中富集,氧含量下降,热值36 MJ·kg-1(乙醇、240℃除外).不同溶剂油成分差别较大,采用水或正己烷,产物主要是脂肪酸类、烷烃及部分酰胺和腈类,采用乙醇或水-乙醇共溶剂,产物主要是酯类、烷烃类.生物质油沸点集中分布在250~500℃,添加乙醇溶剂可显著提高生物质油轻组分含量.     

氨络合法电化学捕集去除城市污泥中重金属的研究

采用自行设计的电动污泥处理装置,以城市污水厂污泥作为试验对象,设置氨水添加比分别为0、0.08、0.10、0.12 (V:V,氨水/试样污泥),在恒定直流电压下运行120h,研究氨络合效应与直接利用阳极产酸对污泥中重金属捕集去除效果的影响.结果表明,阳极酸化对污泥中重金属有一定的溶出去除作用;氨水的添加对电动处理过程中污泥pH值的降低与电流密度的提高没有阻碍,但能够有效提高污泥中重金属的捕集去除率;当氨水添加比为0.12时,污泥中Zn和Cu的捕集去除效果最佳,分别达91.62%和71.49%.氨水添加比为0.08时,Pb的捕集去除率最佳,达47.85%.氨水的添加对污泥中重金属的形态和迁移性有明显影响,主要表现为稳定形态如残渣态、有机结合态的减少及可交换形态的增加.     

Levels and distributions of polychlorinated biphenyls in sewage sludge of urban wastewater treatment plants

Concentrations of polychlorinated biphenyls (PCBs) have been measured in sewage sludge samples from 8 urban wastewater treatment plants in Beijing, China. The PCB congeners were analyzed by isotope dilution high resolution gas chromatography/high resolution mass spectrometry method. The concentration of PCBs ranged from 65.6 to 157 ng/g dry weight (dw), with a mean value of 101 ng/g dw. The dioxin-like PCB WHO-TEQs (World Health Organization-Toxic Equivalents) of the sludge were lower than 1 pg /g dw. Conse...     

Characteristics of sewage sludge and distribution of heavy metal in plants with amendment of sewage sludge

In order to better understand land application of sewage sludge, the characterization of heavy metals and organic pollutants were investigated in three different sewage sludges in Shanghai City, China. It was found that the total concentrations of Cd in all of sewage sludge and total concentrations of Zn in Jinshan sewage sludge, as well as those ofZn, Cu, and Ni in Taopu sludge are higher than Chinese regulation limit of pollutants for sludge to be used in agriculture. Leachability of rig in all of studied samples and that of Cd in Taopu sewage sludge exceed the limit values of waste solid extraction standard in China legislation. Based on the characteristics for three kinds of sewage sludge, a pot experiment was conducted to investigate the effect of soil amended with Quyang sewage sludge on the accumulation of heavy metalo.by Begonia semperfloreas-hybr; Ophiopogon japonicas （L.F.） Ker-Gaw; Loropetalum chindense-var, rubrum; Dendranthema morifolium; Viola tricolor; A ntirrhinum majas; Buxas radicans Sieb; Viburnum macrocephalum; Osmanthas fragrans Lour; Cinnamomum camphora siebold and Ligustrum lucidum ait. Results showed that 8 species of plant survived in the amended soil, and moreover they flourished as well as those cultivated in the control soil. The heavy metal concentration in plants varied with species, As, Pb, Cd and Cr concentration being the highest in the four herbaceous species studied, particularly in the roots of D. morifolium. These plants, however, did not show accumulator of As, Pb, Cd and Cr. The highest concentration of Ni and Hg was found in the roots ofD. morifolium, followed by the leaves ofB. semperflorens-hybr. Levels of Zn and Cu were much higher in D. morifolium than in the other plant species. D. morifolium accumulated Ni, Hg, Cu and Zn, which may contribute to the decrease of heavy metal contents in the amended soil. Treatment with sewage sludge did not significantly affect the uptake of heavy metals by the L. chindense-var, rubrum, however, it significantly affected the uptake of heavy metals by D. morifolium.     

污泥资源化利用的途径与分析

城市污泥既是污染物又是一种资源。从土地利用、回收能源和生产建材等几个方面对污泥资源化利用的途径进行了介绍 ,指出了从源头控制污泥中重金属的含量对土地利用的重要性 ,讨论了利用污泥生产水泥的方法。     

流化床污泥热解实验及产物性质研究

采用流化床反应器对城市污水污泥在400~600 ℃及800~950 ℃温度区间内进行了热解实验.结果表明,污泥受热升温过程经过干燥脱气、分解解聚和裂解缩聚3个阶段,在此过程中发生复杂的化学反应,生成热解气、焦油和半焦.热解温度为550 ℃时液体产率达到最大值,为50.35%,热解气产率在950 ℃时为51.58%,半焦产率随着热解温度升高而逐渐降低,950 ℃时为36.92%.污泥低温热解焦油含有较高百分含量的脂肪族碳氢化合物和类固醇类化合物,经加工可作为液体燃料利用,高温热解焦油可提取多种化工原料.热解气可作为合成气或燃烧利用.