水电工程砂石系统生产废水处理工艺优化研究

针对目前水电工程砂石加工系统生产废水主流工艺存在的问题,现场采集了白鹤滩水电站和乌东德水电站两处废水原样,利用数值模拟、现场及室内实验等多种方法对废水处理工艺主要流程进行了优化。研究表明:模拟预测两级石粉回收预处理总回收率可达60%左右,较单级回收率提高约50%;投加合适的药剂可大大改善废水絮凝沉降性能,当固体颗粒粒径较小时联合投加聚丙烯酰胺(PAM)和氧化钙(Ca O),静水沉速可提高约11倍。泥渣脱水调理剂在药剂类型和药量方面均与前端絮凝沉淀流程中所投加药剂具有一致性,而且"前端一次加药"工艺是可行的。将"隔膜压榨+进气穿流"工艺引入压滤脱水工艺中,单机工作循环时间减少67%的同时,泥饼含水率可降低至15%左右。     

复合调理对淤泥机械压滤脱水特性的影响机理分析

机械压滤脱水是广泛应用的河湖淤泥脱水工艺,淤泥调理方式是影响机械压滤脱水效率的关键因素之一,采用聚丙烯酰胺（PAM）为代表的絮凝剂调理以及絮凝剂与无机调理剂联用的复合调理是2种典型的淤泥调理措施。复合调理近年来发展迅速,研究絮凝剂单一调理与复合调理对机械脱水效率的影响、探索作用机理,对淤泥机械压滤脱水的工艺优化具有重要意义。以官田湖底泥为试验对象,对比PAM、新型低碱性淤泥改性剂（LAC）的淤泥调理、脱水效果,分析PAM及PAM+LAC复合调理淤泥脱水工艺参数,利用压汞试验与扫描电镜（SEM）揭示复合调理对脱水泥饼结构影响。结果表明,调理药剂的促进作用主要在过滤脱水阶段最显著;LAC具有替代和强化PAM调理效果的作用,改善了泥饼卸料性能;加入LAC有助于维持泥饼骨架结构和增大泥饼孔隙,增加的孔隙以开口孔隙为主。     

人工砂石加工系统废水处理工艺设计及应用

针对水电工程砂石加工系统高浊度废水处理工艺存在的排泥管道淤堵、清渣困难、废水澄清及泥渣脱水效果不理想等问题,结合本工程砂石加工系统生产工艺及废水处理目标,设计并采用了“机械预处理+辐流沉淀+高压隔膜压滤机脱水”废水处理工艺,在参数设计、设备选型及配置上考虑一定的裕度。废水处理设施建成后运行稳定,废水处理指标满足行业回用标准且实现了“零”排放,对类似水电工程砂石加工系统废水处理具有借鉴意义。     

集美污水处理厂污泥深度脱水技术探讨

集美污水处理厂原采用的污泥带式压滤脱水产出的泥饼含水率为80%,不满足进入填埋场标准.为解决污泥出路问题,集美污水处理厂于2009年采用污泥深度脱水技术,在浓缩污泥中添加三氯化铁和生石灰进行调理,再经过高压隔膜厢式压滤机脱水,可生产出含水率在60%以下性状稳定的泥饼,符合混合填埋的要求.介绍了工程实际运行情况,并对污泥深度脱水与传统带式脱水进行经济分析.     

构皮滩水电站砂石加工系统废水处理新工艺研究

针对传统砂石加工系统废水处理存在污染环境和费用高的问题,以构皮滩工程为例,介绍了砂石加工系统废水处理新工艺。在构皮滩砂石加工系统废水处理中,率先采用了泥渣分级,混凝浓缩和机械脱水干化联合处理工艺,率先采用美国Derrick公司先进设备进行石粉回收,率先将冶金、污水处理等行业应用成熟的压滤设备引入水电行业进行泥渣机械脱水。与传统工艺相比,新工艺在废水处理效果、土建费用、处理后的废水及沉淀后的石粉回收利用等方面的具有优越性。     

低碱性环保固化剂调理淤泥的板框压滤脱水试验研究

常规药剂用于疏浚淤泥调理效果较好，但存在板框压滤脱水尾水、泥饼的高碱性问题。在室内淤泥调理试验的基础上，研究了低碱性环保固化剂与聚合氯化铝(PAC)、聚丙烯酰胺(PAM)组合调理淤泥的板框压滤脱水过程，对尾水、泥饼的特性进行了分析。结果表明：低碱固化剂与PAC、阴离子聚丙烯酰胺(APAM)联用，在达到同等调理效果的同时，可降低PAC、APAM加药量；在2.5%的低碱固化剂和2.5%、0.12%的PAC、APAM的组合调理下，脱水尾水和泥饼的pH值分别为7.4、7.6,脱水效率比不加药剂时的脱水效率提升42.2%。粒径分析表明：低碱固化剂的加入，提高了泥饼内大颗粒比例，改善了脱水性能。对泥饼的X射线能谱分析(EDS)和X射线衍射(XRD)分析发现：低碱固化剂与淤泥中的黏土矿物反应，生成硅酸盐矿物骨架，有利于降低淤泥的比阻，改善板框压滤脱水性能；低碱固化剂脱水泥饼pH值随时间会缓慢下降，直至稳定，加药量越大，泥饼pH值下降幅度也越大。研究成果为探究新型药剂对淤泥的调理性能及在板框压滤设备上的工艺特性提供了科学依据。     

合肥经开区污水处理厂污泥深度处理技术的应用探讨

合肥经开区污水处理厂污泥高干度脱水项目采用浓缩机、隔膜式板框压滤机作为核心脱水设备,通过投加PAM、PAC进行化学调理改性,可将泥饼含水率控制在60％以下.介绍了板框压滤系统的工作原理和运行参数,对板框设备选型与运行成本进行了详细阐述,使用同一来源污泥对三套污泥脱水系统进行了比较,其中板框压滤机生产每吨干泥需投加PAM...     

淤泥脱水固化原理及在合肥市南淝河清淤工程中的应用

淤泥脱水固化处理是根据淤泥的性质添加一定比例的聚沉剂和土体固结剂、通过压滤作用将淤泥即时分离为悬浮物质指标达到国家污水综合排放标准的清水和含水率在40%以下的硬塑状泥饼,达到泥水分离的效果,有利于淤泥的后续处理。文章介绍了淤泥脱水固化处理原理及在工程中的应用工艺等。     

巴塘水电站砂石系统生产废水处理工艺设计及应用

金沙江上游水域执行地表水环境质量标准Ⅱ类标准,砂石料生产废水需经处理后全部回用(SS<100 mg/L),严禁外排,这对砂石加工系统生产废水处理提出了更高的要求.经对废水悬浮物含量分析和处理设备性能与处理工艺对比分析,结合本工程实际,采用"细砂回收+高位浓缩罐+机械压滤脱水"的工艺处理废水,实现了高效率、低成本运行,达...     

带式压滤脱水机滤布使用的体会

城市污水处理厂在处理污水过程中,会产生大量的污泥,由于污泥含水率高,体积很大,污泥必须首先进行脱水,方能进行进一步处置.污泥脱水是污水处理工艺中的一个重要环节,对于污泥脱水,通常可使用板框压滤机、带式压滤脱水机、离心式脱水机等.目前,大多数城市污水处理厂采用带式压滤脱水机进行污泥脱水,这种脱水机是由上下两条张紧的滤布夹带着污泥,从一连串按规律排列的辊压筒中呈S形弯曲经过,靠滤带本身的张力形成对污泥层的压榨力和剪切力,把污泥层中的毛细水挤压出来,获得含固量较高的泥饼,从而实现污泥脱水.     

Bench- and pilot-scale sludge electrodewatering in a diaphragm filter press.

Electrodewatering is a technique in which pressure dewatering is combined with electrokinetic effects to realize an improved solid/liquid separation and hence increased filter cake dry matter contents. In order to be energy efficient, it is shown that sludge should be dewatered by pressure dewatering to a high extent prior to electric field application, and a sufficient contact time for the electric field must be guaranteed. In order to realize these goals, a bench- and pilot-scale diaphragm filter press suited for electrodewatering were constructed for treatment of sewage and other types of sludges. It was shown that electrodewatering of sludge is a feasible technique, especially for biological sludge types. Other types of sludge are less suited for electrodewatering because of the restricted improvements that can be realized in cake dry matter content and the high electric energy consumption. Furthermore, it was shown in pilot-scale tests that the use of a diaphragm filter press with electrodewatering facilities was very well suited to deliver dry filter cakes of sewage sludge at a moderate energy consumption. Depending on local market prices for investment, operating and sludge disposal costs, this technology may therefore lead to important savings in the sludge management process.     

给水厂污泥脱水技术改造设计方案研究

针对以黄河水为原水的给水厂污泥进行了混凝及优选比阻调理试验,结果表明:当进行给水厂污泥脱水技术改造方案设计时,可以不经过混凝处理,直接利用电厂粉煤灰作为比阻调理剂。细粉煤灰的最佳投加率为20%,粗粉煤灰的最佳投加率为30%,使污泥比阻由1013数量级降至1010数量级,改善了污泥脱水性能,所得滤饼含水率仅为40%~50%,易于剥离,能耗低,所得滤液的色度、浊度、CODMn均达到可直接回用标准。当进行技改工程设计时,建议选用带式压滤机或板框压滤机,既适应粉煤灰调理剂,又可节约投资。     

疏浚泥浆在线脱水的工艺设计及试验

针对梁溪河底泥的性状特点,对疏浚泥浆在线脱水工艺进行了设计和试验.通过泥浆沉降柱试验和药剂上机选型试验,对比了上清液浊度与沉降柱体积、饼含固率和卸料时间,分析确定了药剂选型及投加量;通过滤布透气量选型试验对比了各透气量下的泥饼含固率和滤布穿滤时间,确定了滤布的透气量;最后利用上述试验所得数据进行板框机的现场调试运行,确...     

皂市工程天然砂石加工系统供水及废渣处理

皂市水利枢纽工程的天然砂石加工系统位于渫水池左岸的漫滩地上，枯水期河水走右河槽。为了取得河水冲洗骨料，应用渗渠原理，在河漫滩下预埋集水管至左岸泵站的集水间。设两座沉渣池处理废水废渣。每座沉渣池的工作周期为１４ｄ，即进水７ｄ，压实，脱水３￣４ｄ，挖砂、清洗４￣３ｄ。从设计上较好地解决了废水废渣的处理，对供水工程和废渣处理工艺流程作了详细介绍。     

Enhanced sludge conditioning by enzyme pre-treatment: comparison of laboratory and pilot scale dewatering results.

The effect of enzyme pre-treatment on dewaterability of anaerobically digested sludge was investigated at both laboratory and pilot scale. Our results revealed a significant increase in cake solid content (27% cake solids compared to 18% without enzyme pre-treatment), using an enzyme dose of only 20 mg/L. In order to assess practical application, enzyme pre-treatment was applied at the Wilmington, Delaware (U.S.) wastewater treatment plant, using a pilot-scale centrifuge. However, the efficiency reached in laboratory scale could not be obtained in pilot scale, where the final cake solids content did not exceed 20%. Centrifuge and belt filter press (simulated by Crown Press) dewatering were compared in terms of the process efficiencies in the absence and presence of enzyme pre-treatment. Possible factors that might cause the differences were tested by experimental and statistical comparisons. Results indicated that the higher shear applied in centrifugation is responsible for the lack of improved cake solids. The network strength of sludge determined by rheological measurements revealed that enzymatic treatment weakens the gel structure of the sludge floc through the hydrolysis of extracellular polymeric substances; this allows improved dewatering by filtration processes, but leads to floc deterioration when subjected to high shear during centrifugation.     

陶瓷过滤机在砂石加工废水处理中的应用——以官地水电站工程为例

官地电站砂石料生产系统产生的废水主要来自大、中、小石冲洗筛和棒磨机，正常生产所产生的废水量为280~330 m3/h。为了对废水进行处理，使其达标排放，引进了矿山开采中使用的陶瓷过滤机，其工艺流程为：首先，通过刮砂机将废水中的一部分粗砂进行回收；然后，这部分废水与棒磨机的废水一起进入细砂回收车间进行细砂回收；紧接着，废水流入混合池，在混合池内添加絮凝剂后泵送至沉淀池进行石粉沉淀；最后，将沉淀池的石粉浆液泵入陶瓷过滤机，浆液中的水通过陶瓷片的毛细孔吸出，从而达到石粉和水的分离。滤后的水非常清澈，与厢式压滤机相比，不但工作效率高、运行成本低，而且运行效果稳定可靠。     

浅析天然砂石料加工费用计算

针对目前水利建筑工程定额子目的加工工艺流程及加工机械无法与设计完全匹配的问题,结合某水利工程天然砂石料加工系统的工艺流程,研究计算方法,为天然砂石料加工费用计算提供参考。     

Investigation on effects of aggregate structure in water and wastewater treatment.

The fractal structure and particle size of flocs are generally recognized as the two most crucial physical properties having impact on the efficiency of operation of several unit processes in water and wastewater treatment. In this study, an experimental investigation is undertaken on the effect of aggregate structure in water and wastewater treatment in Hong Kong. The fractal dimension of the resulting aggregate is employed as a measure of the aggregate structure. Small angle light scattering technique is used here. Different amounts of polymers are mixed to bacterial suspensions and the resulting structures are examined. The addition of polymer may foster aggregate formation by neutralization of the bacterial surface charge and enhance inter-particle bridging. The aggregation behavior may affect the efficiency of certain water and wastewater treatment processes such as dewatering and coagulation. The impacts of aggregate structure on two representative processes, namely, ultra-filtration membrane fouling and pressure filter dewatering efficiency, are studied. It is found that the looser flocs yield a more porous cake and less tendency to foul whilst more porous filter cakes yield more ready biosolids dewatering.     

A new approach to improve sludge dewatering using a semi-continuous hydraulic press system.

In future, it will be necessary to incinerate an increasing proportion of the sludge produced by public wastewater treatment. In this context, equipment for more effective dewatering of sewage sludge is required. A hydraulic press system (Bucher HP) which has been used to date in the food industry could represent an alternative to the sludge dewatering systems currently used. The basic suitability of this press system was demonstrated in comprehensive industrial-scale trials at the Glarnerland STP (Switzerland). Dry solids contents of up to 43% were measured in the pressed sludge. Currently, the optimization of individual process parameters is being investigated in a pilot plant at the Schwelm STP operated by Wupperverband (Germany).