东江水源水中有机物分子量分布特征研究

采用超滤膜法考察了东江水源水中有机物分子量分布特点,研究了东江泄洪和不泄洪水源水中有机物分子量分布的变化特征。结果表明,东江水源水在不泄洪期间水源水中的溶解性有机物主要为小分子量的有机物。而在泄洪期间,东江水源水中溶解性有机物主要为大分子量的有机物。UV254的分布和有机物分子量分布一致,DOC与UV254具有良好的相关性。泄洪期间水源水中SUVA值小于3,水体中有机物很难通过常规混凝工艺去除,此结果与水厂的实际运行情况相吻合。     

分离高浓度污泥产酸发酵液的自生动态膜形成机制

采用自生生物动态膜分离高浓度污泥发酵液,研究了动态膜的形成过程及其对污泥发酵液的分离效果.结果表明,自生动态膜的形成过程受污泥浓度的影响较小,污泥浓度仅影响初始膜通量,不影响稳定时的膜通量.膜通量随着滤布孔径和搅拌速度的增大而增大.动态膜的形成过程符合死端过滤模型,分别由以下4个过程构成:先通过与膜基材孔径相似的污泥颗粒堵塞膜基材孔,其后在膜基材上形成单层污泥,进而在膜基材上形成多层污泥,最后,大颗粒污泥继续沉积到污泥层上.动态膜形成后,对污泥颗粒和溶解性COD(SCOD)的截留率分别为98%和28%,对挥发性脂肪酸(volatile fatty acids,VFAs)的渗透率在82%以上,胞外聚合物(extracellular polymeric substances,EPS)中的蛋白质是动态膜的主要成分.     

Application of a hybrid gravity-driven membrane filtration and dissolved ozone flotation (MDOF) process for wastewater reclamation and membrane fouling mitigation

This study proposed a novel membrane filtration and dissolved ozone flotation integrated(MDOF) process and tested it at pilot scale. Membrane filtration in the MDOF process was operated in gravity-driven mode, and required no backwashing, flushing, or chemical cleaning. Because ozone was added in the MDOF process, ozonation, coagulation, and membrane filtration could occur in a single reactor. Moreover, in situ ozonation occurred in the MDOF process, which differs from the conventional pre-ozonation membrane filtration process. Significant enhancement of turbidity removal was further achieved through the addition of membrane filtration. Membrane fouling was mitigated in the MDOF process compared to the MDAF process. In situ ozonation in the MDOF process decreased the fluorescence intensity and transformed the high MW dissolved organics into small MW compounds. For the fouling layer, the extracellular polymeric substance(EPS) contents and cake layer morphology were analyzed. The results indicated that the contents of EPS decreased. Furthermore, a thinner and more loosely structured cake layer formed in the MDOF process. Because coagulation and ozonation occurred simultaneously in a single reactor, the generation of hydroxyl radicals was enhanced through the catalytic effect of Al-based coagulants on ozone decomposition, which further alleviated membrane fouling in the MDOF process.     

Membrane fouling controlled by coagulation/adsorption during direct sewage membrane filtration (DSMF) for organic matter concentration

Unlike the role of the membrane in a membrane bioreactor, which is designed to replace a sediment tank, direct sewage membrane filtration (DSMF), with the goal of concentrating organic matters, is proposed as a pretreatment process in a novel sewage treatment concept. The concept of membrane-based pretreatment is proposed to divide raw sewage into a concentrated part retaining most organics and a filtered part with less pollutant remaining, so that energy recovery and water reuse, respectively, could be realized by post-treatment. A pilot-scale experiment was carried out to verify the feasibility of coagulant/adsorbent addition for membrane fouling control, which has been the main issue during this DSMF process. The results showed that continuous coagulant addition successfully slowed down the increase in filtration resistance, with the resistance maintained below 1.0 × 10¹³ m^− 1 in the first 70 hr before a jump occurred. Furthermore, the adsorbent addition contributed to retarding the occurrence of the filtration resistance jump, achieving simultaneous fouling control and chemical oxygen demand (COD) concentration improvement. The final concentrated COD amounted to 7500 mg/L after 6 days of operation.     

长沙市敢胜垸污水处理厂深度处理工艺的筛选研究

在二级生物处理工艺确定后,深度处理工艺的选择是保证整个工程出水水质的关键。过滤是污水深度处理工艺中最重要的工序,用以去除原水经沉淀后的残留絮体和杂质,具体依据出水效果、处理效率、投资成本和占地等各方面,确定采用深床过滤工艺。从整体优化的角度出发,结合设计规模,进水水质特征和出水水质要求以及当地的实际条件和要求,选择切实可行且经济合理的深度处理工艺方案,是实现整个长沙市敢胜垸污水处理厂最佳工艺方案的保障。     

聚合氯化铁在微絮凝-深床过滤工艺中的应用

以聚铝(PAC)为参照比较研究了聚合氯化铁(PFC)在微絮凝深床过滤工艺中的应用效果.结果表明PFC投药量少(Fe:Al=3:5),其水头滤程可达63h,周期产水率可达1504m³/m²,而PAC的水头滤程为53h,周期产水率为1266 m³/m²;PFC表现出利于延长运行周期,提高产水率等优势.通过截污机理研究表明,PFC具有形成絮体快,与滤料作用迅速,脱水性能好等特点,与PAC相比PFC更适用于微絮凝-深床过滤工艺.     

混凝-微滤膜组合净水工艺中膜过滤特性及其影响因素

采用混凝-微滤膜组合工艺处理微污染原水,间歇抽吸的运行方式连续运行,考察了膜组件的抽吸时间,抽/停时间比和曝气量对膜过滤性能的影响.采用膜通透性J/p作为膜过滤性能的评价指标.结果表明,在各操作条件下,膜通透性J/p由于膜污染的发生均先快速降低,随后随时间缓慢下降.但J/p的初期下降速度和缓慢下降阶段的相对稳定值因操作条件的不同而不同.抽吸时间对膜通透性影响较大,其次为抽/停时间比.在一定的条件下,抽吸时间缩短1/2,产水率可提高2倍;抽/停时间比缩短,产水率可提高50%.当抽吸时间和抽/停时间比分别为15min和3.8时,J/p值较高.曝气量在一定范围内的增加有利于提高膜通透性.本试验中,曝气量由2m³/h增加至4m³/h时,膜通透性可提高约15%,但当曝气量增加到6m3/h时,膜通透性并无显著改善.膜面污染物分析表明,在本研究使用的原水条件下,Si和Ca是主要的无机污染元素.     

空气湿度对自吸过滤式口罩过滤性能的影响研究

口罩是阻止颗粒物进入人体的有效防护用品,其性能优劣直接影响着佩戴人员的健康与安全。采用国标建议的呼吸阻力实验装置与自制的过滤效率实验装置,对自吸过滤式KN90,KN95系列口罩的呼吸阻力与不同相对湿度下的分级过滤效率进行实验研究。结果表明:所研究的6种口罩的呼气阻力与吸气阻力值不仅满足国标要求,而且满足佩戴舒适性的要求;在同一风速下,气流相对湿度的增加,使2种口罩对粒径为1 μm以下颗粒物的过滤效率降低,对1 μm以上颗粒物的过滤效率没有影响。     

浑善达克沙地南缘黄柳林地不同水体氢氧同位素特征

本文选取浑善达克沙地南缘正蓝旗的黄柳林地为研究对象,通过2020年5月至10月野外采集降水、土壤、地下水、植物茎干分析各水体的稳定氢氧同位素特征,比较各水体之间同位素关系。研究发现：(1)土壤水线和植物茎干水线的斜率均小于当地大气降水线,各水体同位素富集程度为地下水<降水<土壤水<植物茎干水,降水的稳定性最差,变异性较大;(2)由于蒸发和降水入渗,浅层土壤δ¹⁸O值和土壤含水量变化显著,而中深层水分受影响较小。降水中的δ¹⁸O值相对于浅层土壤水偏正,并且土壤水的δ¹⁸O值从浅层到深层逐渐呈偏负趋势,雨后各层土壤水波动的峰值出现有一定的时间推迟。(3)黄柳在生长季节主要利用浅层土壤水,各月对其利用率分别为96.20%、90.60%、84.90%、95.50%、86.70%和86.50%,随降水的减少也利用了中深层水;论文通过对黄柳林地内各水体的同位素变化特征的研究,摸清了土壤-植物-大气连续体中不同水体的同位素组成及其相互关系,对于揭示区域水循环的过程和机制至关重要,为浑善达克沙地防护林生态系统的生态水文...     

雨水水质监测与常规处理技术的试验研究

对南京城区屋面雨水径流及某住宅小区的雨水调节池水质做了分析测定,发现屋面初期径流污染很严重,最大值能够达到CODcr290.08 mg/L,NH3^＋-N5.47μg/L,浊度220.5NTU。采用混凝-砂滤工艺对调节池雨水进行了中试规模的试验研究,结果表明选用硫酸铝作为混凝剂时,其最佳投加量为25 mg/L,此时CODcr的去除率为85.14%,浊度的去除率为88.79%,TP的去除率为63.18%。后续选用0.5 mm粒径石英砂过滤混凝沉淀后水,处理后出水水质均值分别为浊度7.5 NTU,TP 0.07 mg/L,NH3^＋-N3.68 mg/L,CODcr27.04 mg/L,水质满足《城市污水再生利用城市杂用水水质》（GB/T18920-2002）、《城市污水再生利用景观环境用水水质》（GB/T18921-2002）的水质要求。