构皮滩水电站烂泥沟砂石系统废水处理及水回收工艺

构皮滩水电站烂泥沟砂石加工系统采用了湿法生产工艺，生产用水量及废水排放量均较大，但废水的排放浊度要求低于200mg／L。根据环境保护的要求，该工程设置了废水处理及水回收系统。该系统投入运行后提高了成品砂的产量和质量，每小时回收细砂和石粉约15t，确保了排放水的悬浮物浓度低于200mg／L，生产用水的循环回收利用率达到80％，回收能力达1100m^2／h，符合了环境保护的要求，取得了较好的经济效益和社会效益。     

丰满大坝重建废污水零排放设计方案论证

丰满水电站位于饮用水水源地二级保护区,工程建设和运行中生产废水、生活污水要求处理后全部回用,不得外排。文中针对水电站建设过程中产生的各种废水,环境保护设计采用了切实可行的水污染治理措施,特别是砂石料加工冲洗废水,同时实现了细砂和石粉的回收利用。     

大朝山水电站人工砂石系统石粉回收工艺

大朝山水电站人工砂石系统为提高人工砂的石粉含量 ,以改善碾压混凝土的可碾性 ,增强其弹塑性、抗分裂性等 ,采用了从制砂过程中产生的废水中回收石粉的新工艺 ,并设计制作了一座钢结构石粉回收装置。该装置投入运行后 ,回收能力达 11m3/h ,满足了碾压混凝土用砂高石粉含量的要求     

双江口水电站1号砂石加工系统生产废水处理工艺

双江口水电站1号砂石加工系统采用湿法生产工艺,生产过程中需对各级骨料用水冲洗,其耗水量大,且产生悬浮物含量极高的废水,如不进行处理就直接排放,将会污染河流水质。结合该工程特点,采用了"沉砂池预处理+辐流沉淀池+斜管沉淀池+过滤机脱水"工艺进行处理。介绍了工艺流程、所需主要设备及各处理车间的生产技术参数。工程实践表明,该废水处理工艺效果显著。     

彭水水电站鸭公溪砂石加工系统主要设备选型

破碎和制砂设备是人工砂石加工系统混凝土骨料生产的核心设备,它们的选型和它们之间的匹配对保证混凝土骨料的质量、降低砂石料单价起着关键作用.通过彭水水电站砂石加工系统主要设备的选型和粗碎、中碎、细碎兼制砂设备的配置,提出了设备选型的一般原则.彭水砂石加工系统制砂作业中采用湿法生产工艺,通过螺旋洗砂机进行砂水分离的过程中,有一部份石粉流失,造成成品砂中石粉不足,碾压混凝土用砂中石粉含量达14%～19%,因此设计了石粉回收工序,采用Derrick公司的2套2E48-120W-4A型细砂回收装置.对砂石加工系统的设计与运行管理具有一定的指导意义.     

简易链式刮泥机在人工砂石系统水处理中的应用

水电工程混凝土人工骨（集）料大多采用湿法生产,生产过程中产生的废水处理和水中石粉回收是一个难点。市场上也有压滤机、刮泥机等多种过滤回收设备,但由于混凝土人工骨料生产周期短、强度大等特点,这些设备运行成本高,难以在实际生产中采用。针对人工砂石加工系统产生的废水一般只含有无机悬浮物的特点,设计了简易键式刮泥机来去除水中的泥沙、悬浮物等。所设计的刮泥机结构和安装简单、运行可靠、成本低,所处理的废水可再用于砂石料冲洗。自制简易刮泥机利用物理方法进行沉淀并清除沉淀物,取得了较好的效果,过滤水满足砂石系统生产用水的要求,达到零排放目标。     

骑马岭水电站砂石加工系统规划设计

介绍了骑马岭水电站砂石加工系统的料源规划、系统规划设计、系统工艺流程及环保措施。该加工系统采用的典型的二段破碎工艺，对中小型水电站混凝土骨料生产系统的设计具有一定的参考价值。同时，该加工系统在废水处理水回收利用及细砂与石粉回收、防尘、降低噪声，以及固体废弃物处置等方面，均采取了相应的环保措施，以减少其对施工人员和周围环境的影响。     

大连开发区湾里净水厂工艺设计介绍

对大连开发区湾里净水厂工艺设计做了简要介绍.该厂采用机械搅拌混合池、竖井网格絮凝池、侧向流斜板沉淀池,以及双层滤料普通快滤池的净水工艺,并对冲洗废水进行回收处理.厂区构筑物按工艺流程自北向南由高至低布置,实现了生产过程中水的重力输送,保证了生产运行安全可靠,降低了运行成本.     

构皮滩水电站烂泥沟砂石系统施工与质量控制

构皮滩水电站工程烂泥沟砂石加工系统设计方案可靠、实用，工艺流程合理、运行稳定，生产出的成品砂符合质量要求，也满足了构皮滩水电站工程施工进度的要求；同时，该系统还采用新工艺、新设备解决了污泥处理、石粉回收、水回收利用和环保问题，有效地提高了水的重复利用率，降低了生产运行成本，减少了对环境的污染。     

日本横滨小雀水厂净水后沉淀污泥的回收利用

本文详述横滨小雀水厂水净化过程中从沉淀池和滤池反冲洗水产生并排放的污泥回收和有效利用方法。在日本横滨市小雀水厂里，排泥水处理过程所产生的泥饼与固化剂和砂混合，制成回收利用的材料，称为回用土，在水厂建设工程中用作回填材料，在学校运动场代替天然砂，为节约资源作了贡献，本文详述水厂回用土制作和利用方法。     

Performance comparison of a pilot-scale membrane bioreactor and a full-scale sequencing batch reactor with sand filtration: treatment of low strength wastewater from a northern Canadian Aboriginal Community.

Northern Aboriginal communities in Canada suffer from poor wastewater treatment. Treatment systems on 75% of Manitoban Aboriginal communities produce substandard effluent despite the presence of sophisticated treatment systems. A 200-litre, pilot-scale membrane bioreactor (MBR) was established on the Opaskwayak Cree Nation to investigate the feasibility of MBRs in mitigating Aboriginal wastewater treatment issues. The pilot system was remote controlled and monitored via the Internet using the program pcAnywhere. The community utilized two existing sequencing batch reactors (SBR) and three sand filters for wastewater treatment. The community wastewater was relatively weak and highly fluctuating which led to poorly settling sludge that readily fouled the sand filters. A comparison study between the MBR and SBR was undertaken from September to December 2003. Operated at a 10-hour hydraulic retention time and 20-day solids residence time, the MBR outperformed the SBR and sand filtration on BOD and suspended solids removal. Furthermore, the MBR showed high levels of nitrification despite relatively cold water temperatures.     

水电工程砂石加工系统废水沉渣脱水工艺研究

水电工程砂石加工系统中的废水沉渣快速脱水是影响废水处理的关键工艺。在对比不同沉渣脱水工艺优势和分析影响其处理效率的因素基础上,介绍了一种适宜砂石生产废水沉渣脱水的新工艺--隔膜压滤,其关键是在常规压滤设备的滤板两侧加装两块弹性膜。分析表明,采用隔膜压滤,可明显缩短脱水工作周期,并显著降低泥饼含水率,提高泥饼力学强度,达到泥渣减容减量、方便转运的目标。可为工程项目废水沉渣脱水处理的研究提供参考。     

Comparison of the nutrient removal efficiency of onsite wastewater treatments systems: applications of conventional sand filters and sequencing batch reactors (SBR).

When domestic wastewater was treated with different onsite applications of buried sand filters and sequencing batch reactors, good organic matter removal was common and effluent BOD7 concentrations from 5 to 20 mg/l were easily achievable. For total nitrogen, effluent concentrations were usually between 20 and 80 mg/l. Good phosphorus removal, even using special adsorption or precipitation materials, was difficult to achieve and large variations occurred. The median effluent concentration of total phosphorus in the most successful sand filter application was less than 0.1 mg/l and other sand filters and SBRs had the median concentrations varying from 1.7 to 6.7 mg/l. These results are based on one year in situ monitoring of 2 conventional buried sand filters, 6 sand filter applications with special phosphorus adsorbing media within the filter bed, 5 sand filters with separate tertiary phosphorus filtration and 11 small SBRs of three different types. The study was carried out in southern Finland during 2003-05. The whole project included monitoring of more than 60 plants of 20 different treatment types or methods, used in normal conditions to treat domestic wastewater. Evaluation of the different systems was made by comparing the measured effluent concentrations. In addition the effluent concentrations were compared to the discharge limits calculated according to the new Finnish regulation.     

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。     

Removal of cyanobacterial metabolites through wastewater treatment plant filters

Wastewaters have the potential to proliferate excessive numbers of cyanobacteria due to high nutrient levels. This could translate to the production of metabolites, such as the saxitoxins, geosmin and 2-methylisoborneol (MIB), which can impair the quality of wastewater destined for re-use. Biological sand filtration was assessed for its ability to remove these metabolites from a wastewater. Results indicated that the sand filter was incapable of effectively removing the saxitoxins and in some instances, the effluent of the sand filter displayed greater toxicity than the influent. Conversely, the sand filter was able to effectively remove geosmin and MIB, with removal attributed to biodegradation. Granular activated carbon was employed as an alternative filter medium to remove the saxitoxins. Results showed similar removals to previous drinking water studies, where efficient removals were initially observed, followed by a decrease in the removal; a consequence of the presence of competing organics which reduced adsorption of the saxitoxins.     

Effects of surfactants originating from reuse of greywater on capillary rise in the soil.

Greywater is all domestic wastewater excluding toilet effluents. Detergents contain surfactants, which account for the highest concentration of organic chemicals in average domestic wastewater. Accumulation of surfactants in greywater-irrigated soils was determined in three household gardens. The effect of surfactants on capillary rise in loess and sand was then tested in the range of concentrations found in the garden soils. The capillary rise of freshwater in sieved oven-dried soil mixed with different concentrations of laundry detergent solution (10% w/w moisture content) was determined. In a second setup, the soil was mixed with freshwater and the rising solution contained different concentrations of detergent solution. The introduction of laundry solution to the soils caused a significant decrease in the capillary rise over the range of concentrations that is found in greywater-irrigated soils. The effect was more noticeable in the sand than in the loess. Interestingly, in the second setup, the capillary rise of the laundry solutions in the sand was almost similar to that of freshwater, whereas in the loess the capillary rise was significantly reduced. It is suggested that accumulation of surfactants in the soil might form water repellent soils that have a significant effect on agricultural productivity and environmental sustainability.     

Tertiary filtration in small wastewater treatment plants.

Tertiary filtration can be proposed in small wastewater treatment plants with impact on protected water bodies. Rotating disk filters may be adopted, in respect to conventional sand filters, when low availability of space and low investment costs are the prevailing conditions. The overall objective of this research was to evaluate the filtration efficiency of rotating disk filters; to compare effectiveness with traditional sand filters; to analyse thoroughly the importance of particle size distribution in wastewater tertiary filtration. In the experimental activity, conventional wastewater quality parameters were investigated and particle size distribution (PSD) was characterized to discuss the filter effectiveness. The effect of design and operation parameters of tertiary filters were discussed related to particle removal curves derived from particles counts. Analysis of particle size distribution can be very useful to help comprehension of filtration processes, design of filtration treatments and to decide the best measures to improve filter performance.     

Bacterial structure of biofilms in wastewater infiltration systems

The objective of the present study was to use a test system for clustering and characterizing the bacterial populations in five wastewater infiltration systems ranging in size from 12 m² to 1960 m² (corresponding to the demand for 4–500 population equivalents). From each system two sand samples were taken and from each sample 88 bacterial isolates were collected. Every isolate was exposed to 52 physiological and biochemical tests. The resulting 880 objects × 52 variable data matrix was subjected to principal components analysis (PCA). After a variable reduction the PCA model revealed a scattered bacteria pattern (score plot) in parts of the sand filters expected to have high loading rates of wastewater, e.g. at the inlet of the filters. This indicates that a diverse bacterial population had developed in response to the carbon and energy source in the wastewater. In contrast to this pattern a more narrow bacteria pattern had developed in low loaded parts of the sand filter. The most important variables explaining the structure of the microbial biofilm at high wastewater load were the ability to ferment sugars and the capacity to sustain different pH levels. The potential to ammonify and grow on nutrient broth was also an important feature. In conclusion, the bacterial test system together with PCA seems to be a useful tool to evaluate the function of a bacterial sand-filter ecosystem.     

An antimicrobial polycationic sand filter for water disinfection

A new sand filtration water disinfection technology is developed which relies on the antimicrobial properties of hydrophobic polycations (N-hexylated polyethylenimine) covalently attached to the sand's surface. The efficacy of the filter disinfection process was evaluated both with water spiked with E. coli and with real aqueous effluent from a wastewater treatment plant. For the former, over 7-log reduction in bacterial count was achieved. With real environmental wastewater secondary effluent samples, the E. coli concentration reduction declined to under 2 logs. This reduced inactivation efficiency compared to the model aqueous sample is likely due to the particulate or colloidal matter present that diminishes the contact between the immobilized polycation and the suspended bacteria. Preliminary sand washing methods were tested to assess potential 'regeneration' approaches. Potential advantages of the proposed approach over conventional disinfection in terms of eliminating harmful by-products and reducing energy consumption are discussed.     

Fenton试剂-石英砂工艺处理铁锰矿井废水

针对铁锰矿井废水中锰离子难去除的问题,本试验采用Fenton试剂-石英砂工艺研究了锰离子的去除效率与机理。结果表明:加入H2O2比不加入对锰离子的去除效果好,各因素的最佳值分别为:当H2O2投加量为0.15mg/L、滤速为8 m/h,pH为7,石英砂粒径为1.0 mm时,锰的最高去除率可达到90.7%。