大庆地区城市污泥中重金属元素含量水平调查与分析

采用原子吸收光谱法和原子荧光光谱法测定了大庆市四座生活污水处理厂污泥中重金属元素含量,平行测定的相对标准偏差在1.6%~4.6%,加标回收率在93.6%~102.1%,表明方法的精密度和准确度都较好,四个污水处理厂污泥中重金属总量大小依次为ZnCuCrPbNiCd,锌的含量高可能与城市排水管道大多采用镀锌材料以及锌的理化性质有关。将其含量水平与标准比较发现:大庆城市污泥中重金属含量水平不高,完全符合《农用污泥中污染物控制标准》的重金属标准,为城市污泥处理、处置和环境管理提供可靠的数据支持。     

龙街镇水厂设计方案的确定

龙街镇位于云南省澄江县西南部,目前仍无给水厂.拟建新水厂规模近期6 000 m3/d.水厂出水水质达到《生活饮用水卫生标准》( GB 5749-2006)的要求.通过对原水水质分析和当地现状的研究,提出采用方便管理的简单处理工艺,并结合地形进行分区供水.简单介绍水源、供水方案等的比选以及主要构筑物的工艺设计,包括设计参数、设备配置等,并对工艺设计特色进行了分析和总结.     

添加污泥对渗滤液循环垃圾填埋层甲烷产生的影响

通过填埋模拟柱实验研究了渗滤液原液循环条件下,新鲜垃圾添加污泥(污水生物处理剩余污泥)的填埋方式对填埋层加速进入稳定的甲烷化阶段的影响.结果表明,原液循环条件下,新鲜垃圾添加好氧污泥后填埋(9∶1,湿基质量比),短期(105d)内不能加速填埋层进入稳定的甲烷化阶段;新鲜垃圾添加厌氧生物处理污泥混合后填埋(9∶1,湿基质量比),能够有效地加速填埋层进入稳定的甲烷化阶段,产甲烷滞后时间和甲烷化过程稳定时间分别为13和51d,实验期内(105d)最大产气速率、实际累积产气量分别为1.08L/kg·d和50.03L/kg(以湿垃圾为基准),其主要机理是引入了大量呈颗粒态聚集的甲烷化菌群.     

Continuous catalytic pyrolysis of oily sludge using U-shape reactor for producing saturates-enriched light oil

Continuous catalytic pyrolysis of oily sludge was carried out in a special U-shape reactor for producing saturates-enriched light oil. The sludge underwent thermal pyrolysis first and then catalytic pyrolysis. During the thermal pyrolysis, chain hydrocarbons were first cracked and further polymerized into aromatics. The effect of temperatures (400–800 °C) on the products was investigated and the maximum liquid yield (67.7%) was obtained at 500 °C. High temperature promoted polymerization, thus the distribution of aromatics in the liquid product was increased and was more concentrated in polyaromatics at 800 °C. In the catalytic upgrading stage, dolomite was used as catalyst and aromatics were adsorbed on it, either aggregated or decomposed. As a result, a light oil product with 57.0% saturates was obtained at the residence time of 8.9?s due to the conversion of aromatics and heavy hydrocarbons into light aliphatic hydrocarbons such as straight chain hydrocarbons. Compared with the oil phase in the raw sludge sample, the content of saturates was increased by 45.0% and that of the asphaltenes was reduced by 88.5%. Meanwhile, the inherent moisture in the oily sludge could participate in the steam reforming reaction, promoting the decomposition of aromatics and leading to an increase in the H₂ generation. Moreover, the release of H₂S was reduced from 0.132 to 0.005?mol per kg sludge and the sulfur content of the oil product was also decreased in the presence of dolomite. The deactivation of dolomite can be attributed to the carbonization of CaO and deposition of polyaromatic coke on the catalyst surface.     

污泥高级厌氧消化前后的热风对流干燥特性

利用热风对流干燥技术对脱水污泥及高级厌氧消化后的污泥进行了对流干燥试验。研究了风温、风速和样品厚度对污泥的干燥效果。结果表明,在相同的工况下,高级厌氧消化后的污泥的干燥效率高于脱水污泥的干燥效率。在风温、风速和污泥厚度分别在120℃、6 m/s和10 mm的工况下,脱水污泥的最高干燥速率为80.7 mg/(g·min),而厌氧消化沼渣的最高干燥速率为486.2 mg/(g·min),厌氧消化沼渣的干燥速率是脱水污泥干燥速率的6倍。在实际处理中,污泥可考虑先经过高级厌氧消化之后,再通过对流干燥达到减量的目的。     

Evaluation of a biological wastewater treatment system combining an OSA process with ultrasound for sludge reduction

Sludge production is an undesirable by-product of biological wastewater treatment. The oxic-settling-anaerobic (OSA) process constitutes one of the most promising techniques for reducing the sludge produced at the treatment plant without negative consequences for its overall performance. In the present study, the OSA process is applied in combination with ultrasound treatment, a lysis technique, in a lab-scale wastewater treatment plant to assess whether sludge reduction is enhanced as a result of mechanical treatment. Reported sludge reductions of 45.72% and 78.56% were obtained for the two regimes of combined treatment tested in this study during two respective stages: UO1 and UO2. During the UO1 stage, the general performance and nutrient removal improved, obtaining 47.28% TN removal versus 21.95% in the conventional stage. However, the performance of the system was seriously damaged during the UO2 stage. Increases in dehydrogenase and protease activities were observed during both stages. The advantages of the combined process are not necessarily economic, but operational, as US treatment acts as contributing factor in the OSA process, inducing mechanisms that lead to sludge reduction in the OSA process and improving performance parameters.     

Reduction process and zinc removal from composite briquettes composed of dust and sludge from a steel enterprise

In this study, composite briquettes were prepared using gravity dust and converter sludge as the main materials; these briquettes were subsequently reduced in a tube furnace at 1000-1300℃ for 5-30 min under a nitrogen atmosphere. The effects of reaction temperature, reaction time, and carbon content on the metallization and dezincification ratios of the composite briquettes were studied. The reduced composite briquettes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). The results show that the gravity dust and converter sludge are combined into the composite briquettes and a reasonable combination not only improves the performance of the composite briquettes, but also leads to the reduction with no or little reductant and flux. As the reaction temperature is increased and the reaction time is extended, the metallization and dezincification ratios of the composite briquettes increase gradually. When the composite briquettes are roasted at 1300℃ for 30 min, the metallization ratio and dezincification ratio reaches 91.35% and 99.25%, respectively, indicating that most of the iron oxide is reduced and the zinc is almost completely removed. The carbon content is observed to exert a lesser effect on the reduction process; as the C/O molar ratio increases, the metallization and dezincification ratios first increase and then decrease.     

普通活性污泥富集好氧氨氧化菌试验

用普通活性污泥在SBR反应器中富集好氧氨氧化菌,反应器的运行周期为1 d,瞬间进水,曝气21.5 h,沉淀2 h,排水0.5 h.pH控制在7.8～8.3,DO控制在0.8～1.2 mg/L,温度控制在30±2℃.采用人工配水,初始人工配水中NH 4-N的浓度为50 mg/L.待稳定后逐渐增加进水氨氮浓度至250 mg/L,每次增加幅度50 mg/L.为定量判定富集过程中好氧氨氧化菌数目的增长情况,每隔15 d对SBR反应器中的污泥进行最大可能计数法(MPN法)测试和MLSS测试.富集培养120 d后,好氧氨氧化菌浓度提高300倍.对比试验证实,pH和温度对好氧氨氧化菌的富集有明显影响.     

油页岩干馏残渣与含油污泥混烧特性

采用热重红外联用技术对油页岩干馏过程中产生的两种固体废弃物油页岩干馏残渣和含油污泥进行混烧实验,通过分析燃烧特性曲线、燃烧特性参数、混烧协同作用、样品中各组分的燃烧特性、混烧动力学参数及气体产物的析出特性,对两种固体废弃物的混烧特性进行了研究。结果表明,油页岩干馏残渣和含油污泥的混烧过程可分为三个阶段。含油污泥的掺入改善了干馏残渣的燃烧状况。干馏残渣与含油污泥的混烧协同作用主要发生在第一阶段和第二阶段。干馏残渣和含油污泥在不同燃烧条件下会出现相互促进或相互抑制的现象。高斯分峰拟合结果表明,混烧过程可分为五个燃烧子反应。基于高斯分峰拟合的Coats-Redfern法计算结果表明,各样品以及各样品中各组分的活化能均不同。含油污泥比例的变化对5个燃烧子反应的影响不同。Friedman法计算结果表明,三个混烧阶段的活化能分别处于50～150、150～200、250～350 k J/mol内。含油污泥促进了干馏残渣的前期和中期的燃烧,但没有改善其后期的燃烧。红外技术分析结果表明,各样品的气体析出规律一致。CO与CO_2排放量的相对值与含油污泥比例不成正比,表明高含油污泥比例不利于充分燃烧。     

污水处理工艺对污泥热处理特性的影响

通过10℃/min时的热重分析,对五种不同性质污泥分别在氮气和氧气气氛下的热解和燃烧特性进行了研究。结果表明,污水处理工艺的“好氧+厌氧”、“厌氧+好氧”过程以及污泥的厌氧消化均使污泥中的有机物结构复杂,导致污泥热解时有机物的分解和析出温度升高,且“好氧+厌氧”过程使污泥中有机物结构更复杂;而对污泥的燃烧过程和燃尽点无影响,但使着火温度升高。利用šatava-šesták 方程对污泥热解、燃烧的反应机理进行了研究。结果表明,五种污泥热解时均呈现为挥发分扩散和随后的化学反应机理函数,而燃烧时则为化学反应和随后的扩散过程。