桂城水厂虹吸滤池改造

桂城水厂虹吸滤池采用三角槽孔板式配水系统。经过多年运行,滤池池体出现了一定程度的倾斜,导致水头损失大,反冲洗周期缩短,反冲洗时间长,滤池跑砂严重等问题。这些严重影响了滤池的正常运行。为此对原虹吸滤池的配水系统、排水槽进行了改造,并对滤料级配进行了优化。一年多的运行结果表明,改造后的虹吸滤池过滤和反冲洗效果明显改善,出水水质优于国家饮用水卫生标准。     

三种典型砂滤池过滤参数优化及过滤性能对比

通过研究国内外三种典型石英砂滤池的出水浊度、颗粒数以及水头损失,对比分析了不同滤速条件下三种滤池的过滤性能,以期达到优化过滤参数及优选滤料的目的。结果表明,水头损失是各滤池过滤周期的主要限制因素,同等条件下美国级配滤料滤池的水头损失增长速率最大,其次是国内级配滤料滤池、国内均质滤料滤池;不同滤速条件下各滤池的出水浊度均保持稳定,国内级配滤料滤池出水浊度在过滤周期末段有上升趋势;出水中颗粒数随着滤速的增加而增大,增大滤速会降低滤池对小颗粒的截留效率,国内均质滤料滤池出水的颗粒含量最低,其次是国内级配滤料滤池、美国级配滤料滤池,各滤池对粒径为3~5μm的颗粒物去除效果最差。综合各因素,国内均质滤料滤池的过滤性能最佳,其次是国内级配滤料滤池、美国级配滤料滤池,三者的最佳滤速分别为(6~7)、8、4 m/h。     

反向翻板滤池的自动控制要点

反向翻板滤池作为翻板滤池的改进工艺，保留了翻板滤池出水水质好、反冲水耗省、土建结构简单等优点，又有级配滤料超强的截污能力，过滤的周期更长。正因如此，由于过滤时污物大量集聚在滤池底部，过滤时水从底部进入，反冲时需要更复杂的控制。     

气水冲洗滤池的新型配气室

近年来,气水冲洗滤池,由于滤料再生好、过滤周期长、冲洗水量少和节省能耗等,已在水处理工艺中得到越来越多的采用,一般多用于配气配水室的滤头分配系统,以完成滤料的高效再生。一般配气室,配气不均匀,难达到设计均匀布气的要求。     

V型滤池反冲洗配水配气系统的设计研究

V型滤池的核心技术就是它的反冲洗配水配气系统,其作用是将反冲洗水和空气均匀地分配到整个滤料层当中,并均匀地收集滤后水,因此滤池反冲洗配水配气系统的设计至关重要。详细分析了影响滤池反冲洗配水配气系统均匀性的各个因素,并给出了相应的设计建议,可供设计人员参考和借鉴。     

虹吸滤池运行问题分析及对策

对于虹吸滤池运行中出现的过程周期太短及出水水质较差的问题，从水厂运行负荷、药剂配制及投加、滤砂级配、反冲洗水头及施工等方面分析了原因，并提出了较详细的处理措施，效果十分显著。     

不同滤料滤池去除浊度和有机物的研究

对比分析了炭砂滤池、活性无烟煤滤池和砂滤池3种不同滤池滤料对浊度和有机物的去除效果。结果表明,炭砂滤池、活性无烟煤滤池和砂滤池对浊度的平均去除率分别为85.06%,83.20%和82.82%;炭砂滤池、活性无烟煤滤池和砂滤池运行效果稳定,在控制出水浊度小于0.50NTU的条件下,炭砂滤池和活性无烟煤滤池出水浊度均可100%满足要求,砂滤池可以达到97.22%;炭砂滤池和活性无烟煤滤池对有机物的去除效果相当,而砂滤池对有机物的去除效果较差,3种滤池对CODMn的平均去除率分别为32.11%,32.13%和19.24%,对UV254的平均去除率分别为32.80%,25.91%和15.30%。     

生物滤池除浊及水头损失的增长特点

生物过滤与常规过滤一样可产生低浊度的出水并具有较长的过滤周期，但水头损失比采用同样尺寸滤料的常规滤池的大，而且增长较快；与单层石英砂滤料滤池相比，活性炭、石英砂双层滤料滤池的水头损失及其增长速度均较小，可获得较长的过滤周期；用加氯水反冲洗的活性炭、石英砂双层滤料滤池的水头损失比用未加氯水反冲洗的小；生物滤池对浊度的去除是传统吸附截留和生物吸附共同作用的结果。     

复合气水反冲洗滤砖在水厂虹吸滤池改造中的应用

本文采用复合气水反冲洗滤砖对虹吸滤池原预制三角槽配水系统进行改造,更换单层滤料为双层滤料,调整滤料级配,使得单格滤池处理水量由原设计152m~3/h提高到170m~3/h,反冲洗时间由16～20min降为10～15min,确保了出厂水浊度小于1NTU。     

普通快滤池改造为气水反冲洗均质滤料滤池工程实践

针对大连大沙沟净水厂原有普通快滤池过滤周期短、产水量下降、反冲洗效果不佳等问题,进行了技术改造。将原有中阻力陶瓷滤砖配水系统改为Azurfloor整体滤板小阻力长柄滤头配水,煤-砂滤料改为石英砂均质滤料,单一水反冲洗改为气水反冲洗,并完善了滤池的自动控制系统。运行情况表明,改造后滤池出水水质提高,反冲洗效果明显改善,产水量增加了10×104m3/d,运行成本减少且滤站实现了自动化运行,经济效益和社会效益显著。     

Comparison of Algal Penetration Through Rapid-Gravity Filter Beds

T ests OF FOUR types of filter media are presented, which show that granular activated carbon performs marginally less well than anthracite/sand or anthracite/sand/garnet in the removal of algae, particulate organic carbon, iron and turbidity. The lengths of run which are achieved by the two granular activated carbon filters are also shorter than those of the other two media. A three-layer filter is better than the anthracite/sand filter for particulate organic carbon, iron and turbidity removal, and the filtrate contains lower mean concentrations of algae.     

New media for effluent filtration

Although deep bed filtration is not new in industrial effluent treatment and advanced sewage treatment, new filter media have been investigated with a view to improving the process. The usual media, like sand and anthracite, may be augmented or replaced by hydroanthracite, pumice and expanded slate. The properties of these media are described. Laboratory and pilot tests illustrate their use for effluent treatment in Switzerland.     

炭砂滤池在饮用水处理中的研究现状及前景

面对普遍存在的微污染水源水质和生活饮用水卫生标准的日益提高,自来水厂有必要采用深度处理工艺。炭砂滤池在保证有效去除浊度的基础上,可以增强对有机物和氨氮等污染物的去除效果,且炭砂滤池只需对水厂砂滤池进行改造,基建及日常运行管理费用较低,因此适用于我国自来水厂的提标改造。炭砂滤池的运行受到反冲洗、温度、预氧化和空床接触时间等因素的影响,对于其出水安全性尤其是出水生物安全性的问题亟待研究。为保证炭砂滤池在工程上的成功应用和推广,需进一步研究滤料级配、组合工艺运行以及滤池内的微生物特性。     

不同滤料对丹江口水库水的过滤效果研究

以丹江口水库中试基地的沉淀池出水作为试验用水,对比研究了细石英砂单层滤料、粗石英砂单层滤料、无烟煤单层滤料及无烟煤-石英砂双层滤料的过滤效果。结果表明,4组滤柱对浊度的去除效果相近,但无烟煤-石英砂双层滤柱受进水浊度变化的影响较小,抗冲击能力较强,出水浊度相对稳定;无烟煤-石英砂双层滤柱与无烟煤滤柱对有机物的去除效果优于细石英砂与粗石英砂滤柱,无烟煤-石英砂双层滤柱与无烟煤滤柱对CODMn的去除率分别为(31.45±10.39)%和(28.23±9.15)%,对UV254的去除率分别为(13.05±5.3)%和(14.23±4.97)%;细石英砂滤柱水位增长最快,且运行周期最短,无烟煤-石英砂双层滤柱与无烟煤滤柱水位增长相对较慢,运行周期是细石英砂与粗石英砂滤柱的2～3倍。     

A comparison of media types in acetate fed expanded-bed anaerobic reactors

A synthetic feed, containing acetate as the only carbon source, was used to start-up four different anaerobic expanded-bed reactors containing three different types of microbial attachment media. The media types used were low-density anthracite, granular activated carbon (GAC) and two sizes of sand. All media types were of the same average diameter, 0.7 mm, except for a smaller sand, 0.35 mm. These media types were chosen to compare surface roughness, macroscopic shear stresses due to upflow velocity and sphericity. The 0.7 mm sand required the greatest upflow velocity, 16 cm/s, while the other reactors had upflow velocities of 5.5–6.0 cm/s. Sand had the least surface roughness and GAC had the roughest surface, while anthracite had the most angular shape. At steady-state, the GAC reactor retained 3.75–10 times the attached biomass retained on the other media tested and the GAC reactor accumulated biomass at a faster rate during start-up. Shear losses reflected the biomass accumulation with the two sand and anthracite media having shear loss coefficients 6–20 times greater than that of the GAC medium. Sand induced the formation of sludge granules in both sand reactors with two species of methanogens and stability of the sludge blankets was critical to reactor performance. Scanning electron microscopy demonstrated that attached growth developed in crevices where biomass was protected from shear forces. Attached growth on the sand and anthracite media was located only in crevices, while the GAC medium is completely covered with crevices and biofilm developed on the entire GAC particle. Surface roughness was critical to biofilm development with the rougher surface providing the better attachment medium.     

Optimization of the extended terminal subfluidization wash (ETSW) filter backwashing procedure

The increased passage of particles and microorganisms through granular media filters immediately following backwashing is a common problem known to the water treatment community as filter "ripening" or maturation. While several strategies have been developed over the years to reduce the impact of this vulnerable period of the filtration cycle on finished water quality, this research involves a recently developed filter backwashing strategy called the extended terminal subfluidization wash (ETSW). ETSW is a method of terminating the backwash cycle with a subfluidization wash for a period of time sufficient to pass one theoretical filter-volume of water upward through the filter. ETSW was shown to remove significantly greater quantities of backwash remnant particles thereby reducing the magnitude of filter ripening turbidity and particle count spikes. Optimum ETSW flow rates were determined for deep-bed anthracite and granular activated carbon filters herein by monitoring filter effluent turbidities and particle counts during the filter ripening period. Optimality of the coagulation process was also shown to influence the magnitude of filter ripening particle passage. ETSW was found to be equally effective for biological and conventional deep-bed anthracite filters.     

Biofiltration for removal of BOM and residual ammonia following control of bromate formation

Nitrification was developed within a biological filter to simultaneously remove biodegradable organic matter (BOM) and residual ammonia added to control bromate formation during the ozonation of drinking water. Testing was performed at pilot-scale using three filters containing sand and anthracite filter media. BOM formed during ozonation (e.g., assimilable organic carbon (396-572 microg/L), formaldehyde (11-20 microg/L), and oxalate (83-145 microg/L)) was up to 70% removed through biofiltration. Dechlorinated backwash water was required to develop the nitrifying bacteria needed to convert the residual ammonia (0.1-0.5 mg/L NH(3)-N) to nitrite and then to nitrate. Chlorinated backwash water resulted in biofiltration without nitrification. Deep-bed filtration (empty-bed contact time (EBCT) = 8.3 min) did not enhance the development of nitrification when compared with shallow-bed filtration (EBCT = 3.2 min). Variable filtration rates between 4.8 and 14.6 m/h (2 and 6 gpm/sf) had minimal impact on BOM removal. However, conversion of ammonia to nitrite was reduced by 60% when increasing the filtration rate from 4.8 to 14.6 m/h. The results provide drinking water utilities practicing ozonation with a cost-effective alternative to remove the residual ammonia added for bromate control.     

改性砂高速过滤技术用于污水再生回用的研究

采用SJ材料作为改性剂对石英砂滤料进行改性,经测定,其表面的物理化学性能优于石英砂.将改性砂应用于煤砂双层滤料高速过滤工艺,并处理某污水厂的二级出水,其出水的平均浊度、COD、UV254、PO43--P分别为1.23 NTU、27.4 mg/L、0.133 5 cm-1、0.42 mg/L,对各项指标的去除率均高于石英砂滤料,且完全符合GB/T 18920-2002标准中的城市杂用水水质要求.研究发现,高速过滤工艺应该以自然条件下的最大滤速为起始滤速;污染物积累和滤层负压导致水中溶解气体的析出会减小有效过水断面面积,这是引起滤速衰减的主要原因.     

强化常规工艺对三卤甲烷前体物的去除效果研究

分别通过小试和生产性试验研究了强化混凝和强化过滤对三卤甲烷前体物的去除效果。结果表明,强化混凝能有效提高三卤甲烷前体物的去除效果,两组试验去除率最高分别可提高至50.62%和44.75%;相对石英砂滤池,采用炭砂滤池和活性无烟煤滤池进行强化过滤可将三卤甲烷前体物的去除率提高10%~20%,强化过滤出水加氯消毒后三卤甲烷生成总量比石英砂滤池出水低30%~40%,强化过滤后三卤甲烷生成风险显著降低。