PAM-粉煤灰体系在煤泥水絮凝沉降过程中的作用及机理

以煤泥水COD、SS、动电位、污泥比阻为切入点,分析了煤泥水的特点及难以絮凝沉降的原因,并研究了PAM-粉煤灰体系在混凝沉降作用中的机理。研究结果表明:PAM-粉煤灰法在最优条件下,清水分离率47%、沉降速度0.357 mm/s;上清液:pH=7.35,SS=55.57 mg/L,COD=37.72 mg/L;污泥比阻为0.062×10^15 m/kg,满足煤泥水循环标准。     

Paper mill sludge as a renewable substrate for the production of acetone-butanol-ethanol using Clostridium sporogenes NCIM 2337

In the present study, pre-treated paper mill sludge (PMS) was evaluated extensively as a substrate for production of acetone-butanol-ethanol using Clostridium sporogenes NCIM 2337. The PMS was subjected to three types of pre-treatment methods namely alkali, mechanical, and thermal treatment and was analyzed by SEM. The pre-treatment of PMS by alkali was observed to be more effective over the other pre-treatment methods. The alkali pre-treated sludge was then made to undergo fermentation, which showed the conventional process of acidogenesis followed by solventogenesis. The acetone, butanol, and ethanol concentration for 15% alkali pre-treated PMS was estimated to be maximum.     

Study on migration characteristics of heavy metals during oil sludge incineration

Experimental and simulation studies on the migration characteristics of heavy metals during the incineration of OS were conducted with a tube furnace reactor and thermodynamic equilibrium calculation software FactSage, respectively. The results showed that when the incineration temperature increased from 800°C to 1100°C, the release rates of heavy metals such as Cr, Pb, Cu, Zn and Ni increased gradually and reached the maximum at 1000°C. When the excess air ratio increased from 1.0 to 1.4, the release rates of heavy metals such as Cr, Pb, Cu, Zn and Ni first decreased and then became steady. The content of gaseous hydroxide of Cr and gaseous chlorides of Pb and Cu increased while the chemical forms of Zn and Ni did not change obviously with the increase of combustion temperature or excess air ratio.     

污泥生物炭中氮硫行为及环境效应研究进展

污泥生物炭中氮硫元素含量高，其氮硫行为和环境效应对全球气候变化的影响不容忽视。以往的研究中，研究者往往以富碳生物炭作为主要研究对象，关注碳对全球气候变化的行为和功效，而对氮硫元素的作用关注不够。本文从原始污泥基本性质到其热解过程，再到生物炭的老化，逐步对污泥生物炭整个生命周期内氮硫的行为及其环境效应研究进行综述，并对未来应注重开展的研究方向进行展望，为生物炭中氮硫元素固定、释放及与之关联的环境效应和温室气体排放控制研究提供理论基础。分析表明，污泥中氮元素含量普遍高于硫元素，且热解过程中氮比硫更容易转移至气相产物。氮硫元素随热解温度的增加，在三相产物中的分配都是炭中持续减少，油中先增后减，气中一直增加。高温（＞800℃）条件下，气相中的氮含量高于固相，而硫元素则仍然主要存在于固相中。污泥生物炭老化及其环境效应研究表明，污泥生物炭氮硫元素与土壤的相互作用及其温室效应问题在今后的研究中应引起重视。     

不锈钢酸洗污泥对烧结黏结相与平衡相的影响

 不锈钢酸洗污泥安全填埋占用土地且难以消除对环境的危害，将酸洗污泥作为烧结配料使用有望回收其中铁、铬、镍等金属，并充分利用其中的熔剂组分，实现酸洗污泥在冶金企业的闭路资源化利用。铁矿粉配加酸洗污泥烧结黏结相强度试验表明，随着酸洗污泥配加比例的增加，黏结相强度先增加后减小，且随着碱度的增加整体减小，当酸洗污泥配加比例为10%时，试样中赤铁矿、磁铁矿质量分数最大，枪晶石质量分数较小，在碱度为1.5时于1 280 ℃焙烧4 min，试样的黏结相强度最大可达15.12 kN。平衡相烧结试验表明，配加酸洗污泥能改善烧结矿质量，铁矿粉配加10%的酸洗污泥，碱度为1.5，1 300 ℃烧结240 min后，烧结矿的矿相组成和微观结构最好，综合性能最佳。     

三维颗粒物质的能量最小化模拟方法

颗粒物质是大量宏观颗粒的集合,广泛存在于自然界,日常生活和工业生产中.颗粒物质的运动表现出非常复杂的现象,如堵塞(jamming)等.颗粒物质体系的定量研究仍是一个巨大的挑战.本文采用能量最小化方法对颗粒物质进行准静态模拟.对一些典型的非线性优化方法,如共轭梯度法,拟牛顿法等,通过预条件来提高这些方法的效率.这些预条件方法基于颗粒体系的几何结构和能量函数来构建.通过对一些典型的准静态过程,如压缩和剪切试验的数值模拟,观察到对三维颗粒体系,预条件方法可以有40%左右的效率提升.     

Enhanced sludge stabilization coupled with microbial fuel cells (MFCs)

This study presents research results on electricity production from waste activated sludge using MFCs during stabilization process. Different MFC configurations equipped with various electrodes were used. Voltage measurements were continuously done during 35 days of MFC operation. Experimental results showed that bioelectricity generation was linked to volatile solids (VS) and protein reductions as a fraction of extracellular polymeric substances (EPS). Double chamber MFC reactor equipped with graphite electrodes had better power and current densities as 312.98 mW/m² and 39.07 μA/cm² while single chamber MFC equipped with titanium electrodes revealed better power and current densities as 97.60 mW/m² and 17.63 μA/cm², respectively. Molecular results indicated that power outputs of MFCs effected by diverse microbial communities in anode biofilms. Although organic matter degradation is reported as 35%–55% VS reduction for digesters, this research provided a promising approach for sludge stabilization with enhanced degrading of organic matters up to 75% by using MFCs.     

Nymphoides peltatum as a novel feedstock for biomethane production via anaerobic co-digestion with waste sludge

Nymphoides peltatum (NP) is exploited as a novel feedstock for biomethane production via anaerobic co-digestion with waste sludge (WS). Batch experiments are conducted under mesophilic condition at NP/WS of 1/3, 2/2, 3/1, 0/4 and 4/0 based on volatile solids (VS). Prior to anaerobic digestion (AD), NP undergoes only natural drying and grinding. The maximum net cumulative methane yield (265.16 mL CH₄·g VS_added^?1) and the highest gross VS removal rate (56.12%) are obtained at NP/WS of 1/3. The kinetic analysis by the modified Gompertz model fit hinted that 28 days is adequate for methane recovery and co-digestion significantly accelerates the digestion rate. Synergetic effect is corroborated to exist in co-digestion due to amiable conditions in term of total ammonia nitrogen, free ammonia, pH, volatile fatty acids and total alkalinity. High-throughput 16S rRNA pyrosequencing reveals that Bacteroidetes, Firmicutes, Methanosarcina and Methanosaeta are conducive to AD of NP.     

Development of a void ratio-moisture ratio-net stress framework for the prediction of the volumetric behavior of unsaturated granular materials

Despite extensive research on the behavior of unsaturated fine-grained materials, there is still a lack of understanding of the volumetric behavior of unsaturated granular materials. In this research, a model has been developed to predict the fundamental volumetric behavior of unsaturated granular materials through loading and wetting state paths. In this regard, a loading-wetting surface was developed in a space of void ratio-moisture ratio-net stress. A distinctive feature of the proposed model is the relative simplicity in obtaining the model parameters using conventional geotechnical testing equipment. Two types of recycled granular materials, commonly applied in unbound pavements were used, namely, recycled crushed brick (CB) and excavation waste rock (WR). The uniqueness of the developed surface was evaluated by employing a number of loading and wetting state paths. The results indicate that the developed surface is unique in its loading state paths; however, it only shows uniqueness in its wetting state paths for stress levels greater than 2000 kPa. The proposed model seeks to introduce the application of the unsaturated soil mechanics theory, for predicting the behavior of granular materials in the field, by providing a practical and cost-effective methodology.