污泥堆肥过程中氮素损失和氨气释放的动态与调控

通过不同鼓风强度、分层堆肥和添加吸湿剂的自动控制堆肥中试,研究了城市污泥堆肥过程中温度、挥发性固体含量、氮素含量和氨气释放浓度的变化.结果表明,在堆肥升温较快的处理中,挥发性固体的降解速度较快,污泥中的氮素容易向氨氮转化,使释放的氨气浓度升高;增大鼓风强度,有利于促进堆肥的升温和腐熟,加速无害化过程,但释放的氨气浓度较高;在保持整个堆体中污泥比例不变的前提下,分层堆肥可以显著提高堆肥的升温效果并减少氨气的释放.     

印染污泥干燥过程中气体污染物的释放研究

在污泥干燥过程中必须寻找一个最适的操作条件,以从源头上控制气体污染物的产生.通过试验研究了印染污泥干燥过程中干燥温度和干燥程度对典型无机气体污染物(NH3、H2S)和有机气体污染物(苯系物)释放量的影响情况.结果显示,两类污染物的释放量均随干燥温度的升高而增加,且均存在释放量突增温度,分别在140和120℃附近;干燥程度对气体污染物释放量的影响表现为当含水率接近35％且持续下降时,NH3和H2S的释放量显著增加,对苯系物而言此临界含水率约为40％.     

城市污泥堆肥技术研究

１　城市污泥的泥质评价城市污水处理厂污泥主要来自初沉池污泥和剩余活性污泥,污泥中有机物含量随季节变化,夏低冬高。初沉池污泥有机物浓度低于剩余污泥,二者的混合污泥有机物含量平均６０％左右,与发达国家的７０％相比偏低。天津市纪庄子污水处理厂污泥组分分析见表１。　　污泥中有机含量及其组分均是影响污泥消化和污泥生物能产量的主要因素。污泥的农田利用之所以受到人们重视,主要原因是污泥中含有比较丰富的有机营养成分氮、磷、钾等元素。纪庄子污泥多年平均值与农家肥的比较见表２,重金属及有毒物质含量见表３。表１　纪庄…     

污泥堆肥过程中致臭挥发性有机物的产生和释放

利用气相色谱/质谱联用仪分析了郑州八岗污泥处置厂污泥好氧堆肥发酵高温前期(第5天)的挥发性有机物(VOCs)产生与释放特征。结果表明,污泥堆肥过程中产生的主要致臭VOCs为甲硫醇、甲硫醚、二甲二硫醚、丙酮、1-丁烯;致臭VOCs从堆体内部到车间人员活动处的扩散过程中,其浓度可降低89.3%~99.9%,低于《工作场所有害因素职业接触限值》(GBZ 2—2002)和《恶臭污染物排放标准》(GB 14554—93)所规定的限值,厂区不存在VOCs污染风险。     

负荷期污泥处理湿地中的温室气体排放特征

污水生物处理过程中产生的大量剩余污泥富含植物生长必需的营养物质,为污泥处理湿地这一新型剩余污泥处理技术的开发提供了可能。利用原位静态箱法对3个污泥处理湿地(S1、S2、S3)进行负荷期温室气体排放特征研究,发现在污泥处理湿地系统中CH4、CO2的排放通量表现出明显的季节特征,两者的排放情况均表现为夏季>秋季>春季>冬季的趋势,并且夏季远高于其他季节。污泥处理湿地S2(种植芦苇、通风)和S3(种植芦苇、无通风)的CH4总排放量分别比S1(无芦苇、通风)高出30.5%、15.5%,S1、S2和S3的CH4和CO2总排放量(当量CO2)处在同一量级,全球增温潜能值大致相当。     

不同类型的外加碳源对污泥堆肥过程氮素损失的影响

以城市污泥为研究对象,采用葡萄糖、蔗糖、秸秆粉及其混合物作为外加碳源,研究了不同类型的外加碳源对堆肥系统一次发酵周期内氨气挥发的影响。探讨了碳源的降解效率与堆肥系统氮素损失的作用关系。结果表明,与对照试验氨气挥发总量相比(3.05g/kg·ds),单独添加葡萄糖(2.46g/kg·ds)与蔗糖(2.17g/kg·ds)均能控制氨气的挥发,但单独使用秸秆粉没有显著效果(3.1g/kg·ds)。蔗糖与秸秆粉混合添加对高温期氨气挥发的控制效果最好(1.92g/kg·ds),堆肥系统中总氮损失由对照试验53.1%减少至27.7%;堆肥过程中氨气挥发与碳源的降解具有显著负相关性(R=-0.94,p0.005),秸秆粉与葡萄糖、蔗糖混合添加增强了微生物对有机碳的降解能力,促进无机氮的固定作用,减少了氮素的损失。     

污泥干化过程恶臭气体释放的研究进展

降低污泥含水率是污泥处理的重点之一,污泥干化是降低污泥含水率最有效的方法之一。介绍了污泥干化过程中恶臭气体的检测方法,恶臭气体的种类和浓度与干化时间和温度的关系以及恶臭气体产生的机理,分析了目前研究工作的不足并提出了建议。     

污泥堆肥过程中微生物群落的形态变化研究

将高效除臭发酵菌接种到污泥堆肥中,通过分子生物学技术的引入,对污泥堆肥化过程进行研究,获得反应过程中微生物群落结构随时间变化图谱,直观剖析堆肥过程中细菌群落组成结构的变化,更好地反映堆肥化过程中生物化学的变化。结果表明,在污泥堆肥开始阶段中接入高密度、高活性的菌剂,不仅加快堆肥中有机物的分解、缩短堆肥化过程,而且提高了污泥堆肥的质量。     

脱水污泥堆肥的生产性试验研究

通过对脱水污泥进行堆肥的生产性试验研究，总结了堆肥过程中温度、通风量、有机成分和含水率的变化规律和控制方法，对污泥堆肥的水分调节也进行了分析。     

典型沥青路面热再生能耗及温室气体排放计算分析

为了分析沥青路面建设和维修养护过程中的能耗及温室气体(GHG)排放情况,以改性沥青SMA路面为例,调查分析了路面现场热再生、厂拌热再生施工各环节的能耗及温室气体排放情况,并与传统的铣刨重铺工艺进行了对比分析,结果显示,现场热再生所需的能耗最高,厂拌热再生工艺最低,传统的铣刨重铺工艺居中。     

模拟人工湿地植物混种对氮去除及温室气体排放的影响

为探究植物多样性对人工湿地生态系统功能的影响,在模拟人工湿地试验系统中配置的两种植物物种单种和混种处理方案。结果表明:单种系统的出水硝态氮(NO-3-N)和铵态氮(NH+4-N)及温室气体排放与混种系统无显著差异;单种系统基质无机氮积累量显著高于混种系统;单种系统生物量(地上、地下和总量)及氮积累量(地上和总量)显著低于混种系统;根据物质平衡法,单种系统植物吸收对系统氮去除的贡献显著低于混种系统,反硝化作用却显著高于混种系统,基质存留的总无机氮(TIN)也显著高于混种系统(P<0.05)。     

城市污水厂污泥处置技术分析及福州市污泥处置的思考

本文对城市污水厂污泥处理处置主要技术进行分析,并阐述了国外污泥处置技术发展趋势,提出了污泥处理处置工作急需解决的问题。结合当前的污泥处置技术发展趋势,通过对福州市污水厂污泥处置现状及存在问题分析,提出了福州市今后的污泥处置技术路线:将厌氧消化做为有效减容、减量的手段,对污染物指标达到国家土地利用标准的污泥考虑土地利用,污染物指标不符合国家土地利用标准的污泥考虑焚烧和建材利用。     

The effects of temperature, pH, and ammonia concentration on the inactivation of Ascaris eggs in sewage sludge

The reported inactivation of Ascaris eggs during alkaline sludge stabilization is highly variable. The objective of our research was to better understand the sources of this variability by quantifying the effects of temperature, pH, and ammonia concentration on the inactivation of indigenous Ascaris eggs in wastewater sludge. Primary sludge was supplemented with ammonia (0, 1000, and 5000mg/l NH(3)-N) and Ca(OH)(2) and incubated in sealed bottles across the range of temperatures (20, 30, 40, and 50 degrees C) and pH (7 and 12) that may be encountered during treatment. Changes in egg viability over time were fit to a two-parameter kinetic model (shoulder and first-order region); to compare treatment conditions, the time for 99% inactivation (t(99)) was also calculated. Each 10 degrees C increase in temperature caused a significant decrease in t(99) at every pH and ammonia concentration tested. At 50 degrees C, the effect of temperature was dominant, such that no effect of pH or ammonia was observed. At 30 and 40 degrees C, raising the pH from 7 to 12 decreased t(99), but at 20 degrees C no pH effect was seen over 80 d (very little inactivation occurred). At 20, 30, and 40 degrees C, the addition of ammonia dramatically decreased t(99). The effect of pH could not be completely separated from that of ammonia, as the unamended sludge samples contained 100-200mg/l indigenous ammonia. Because temperature, pH, and ammonia all contributed to Ascaris egg inactivation, it is essential that these parameters are measured and accounted for when assessing the effectiveness of alkaline stabilization. Furthermore, inactivation by ammonia could be exploited to improve the effectiveness of alkaline sludge stabilization.     

污水处理厂污泥脱水性研究

对城市污水厂未消化污泥进行了絮凝脱水试验,用L9正交表对影响絮凝沉淀的各种因素进行了比较,结果表明,高价态盐的混凝效果要好于低价态,而混凝剂加药量及混凝时间等因素也对结果有很大影响。     

污水处理厂污泥资源化利用技术分析

生活及工业中产生的污水量不断增加,污水处理厂处理后产生的污泥量也随之增大。目前,我国污泥的主要主要处理方法为填埋和焚烧。本文介绍了污水处理厂污泥组成、传统污泥处理方法、污泥资源化处理方法,并对污泥资源化处理案例进行分析,发现未来的污泥处理应侧重于资源回收、减少影响环境及节约经济成本等方向。     

Fate of organotins in sewage sludge during anaerobic digestion

Adsorption onto sewage sludge is an important process for the elimination of tributyltin (TBT) from wastewater. However as the disposal of sewage sludge to agricultural land is a significant route for recycling biosolids, there exists an issue as to whether the potential long-term build-up of organotins in agricultural soil is acceptable, from a human health and environmental point of view. For the sustainable use of biosolids in agriculture it is essential to control and reduce the quantities of persistent pollutants such as organotins in sewage sludge. In this study, a sampling program was designed to establish the levels of TBT (and other organotins) in sewage sludge and their reduction during anaerobic treatment and processing prior to disposal. Experiments were also undertaken to assess the fate of TBT in laboratory scale anaerobic digesters where the influence of digester operating parameters could be evaluated. Organotin concentrations were determined using capillary gas chromatography with flame photometric detection. The results demonstrated that the majority of TBT remained concentrated in the solid phase (sewage sludge). Concentrations of TBT in sewage sludge were approximately 18 mg kg(-1) (dry weight) and both laboratory experiments and fieldwork demonstrated that degradation of TBT during anaerobic digestion of sludge was minimal.     

Influence of forced air volume on water evaporation during sewage sludge bio-drying

Mechanical aeration is critical to sewage sludge bio-drying, and the actual water loss caused by aeration can be better understood from investigations of the relationship between aeration and water evaporation from the sewage sludge bio-drying pile based on in situ measurements. This study was conducted to investigate the effects of forced air volume on the evaporation of water from a sewage sludge bio-drying pile. Dewatered sewage sludge was bio-dried using control technology for bio-drying, during which time the temperature, superficial air velocity and water evaporation were measured and calculated. The results indicated that the peak air velocity and water evaporation occurred in the thermophilic phase and second temperature-increasing phase, with the highest values of 0.063 ± 0.027 m s^?1 and 28.9 kg ton^?1 matrix d^?1, respectively, being observed on day 4. Air velocity above the pile during aeration was 43–100% higher than when there was no aeration, and there was a significantly positive correlation between air volume and water evaporation from day 1 to 15. The order of daily means of water evaporation was thermophilic phase > second temperature-increasing phase > temperature-increasing phase > cooling phase. Forced aeration controlled the pile temperature and improved evaporation, making it the key factor influencing water loss during the process of sewage sludge bio-drying.     

The behaviour of nitrilotriacetic acid during the anaerobic digestion of sewage sludge

In laboratory simulations of the anaerobic sludge digestion process, the impact of the detergent builder nitrilotriacetic acid (NTA) on digester efficiency has been studied. It was concluded that NTA at concentrations up to 30 mg l⁻¹ had no adverse effect on anaerobic digestion. However, analysis of the digested sludge indicated that only 29–45% of the influent NTA was removed during treatment. To differentiate between biological and physical processes of removal, biological activity in the digesters was arrested by the addition of sodium azide. Effluent NTA concentration did not increase indicating that biological activity was not responsible for the removal observed.Batch experiments undertaken to evaluate NTA solubility in digested sludge (containing azide) at two solids concentrations indicated a decrease in soluble NTA with increasing solids concentration.It is concluded that the removal of NTA observed during anaerobic digestion was not biological and in part was the result of adsorption onto the solid phase.     

Study the surface color of sewage sludge mortar at high temperature

In this study, with the help of digital image analysis method, the surface color changes of sludge ash mortar specimens at various elevated temperatures are studied. Moreover, the influences of temperatures on surface color changes of mortars are investigated. Selected portions of cement are replaced by three different amounts of sewage sludge ash and six varied temperatures are then assigned. Results indicate that the addition of sludge ash in the mortar has significant influence on the surface color changes. Intensities of red, green, and blue are reduced with the ash additives. Our study also shows that the grayscale of sand could be one of the important factors in assessing the high temperatures of fire. Distributions of colors and brightness of mortar surface with temperatures quantified by image analysis can serve as a useful tool in detecting properties of mortars at high temperatures.