V型滤池设计的一点改进

通过对V型滤池工作原理及生产实际应用情况分析 ,针对V型滤池运行中存在的问题提出了一些改进措施 ,使V型滤池运行更加安全可靠     

V型滤池设计、施工及运行总结

本文重点介绍了成都市自来水总公司水二厂Ｖ型滤池的设计要点、施工特点及运行情况。     

混凝土V型滤池的施工

介绍了V型滤池的基本结构和运行过程及清源水厂V型滤池的概况,分析了混凝土V型滤池的池体施工存在二次浇筑和施工精度不能满足工艺要求等问题。采用了二次浇筑施工缝使用止水钢板连接和将其中施工精度要求较高的V型表面扫洗孔施工采用先预留洞后安装不锈钢管、滤板先找平后安装、H型排水槽依靠外贴瓷砖来调整水平度等方法,解决了池体二次浇筑混凝土渗漏水及混凝土施工精度不能满足工艺要求的问题。     

V型滤池施工及运行中应注意的问题

根据V型滤池施工及运行经验,对V型滤池施工中所遇到的滤板安装的平整度控制等问题进行了分析,并探索了影响V型滤池运行稳定的原因,提出了解决措施,使V型滤池运行更加安全可靠。     

V型滤池清水阀门两种控制方式的比较

V型滤池采用恒液位过滤,通过调节清水阀门的开度控制出水量以保持液位恒定,清水阀门通常采用蝶阀。以上海南市水厂一、二期V型滤池为例,比较分析了阀门的两种控制方式,总结了阀门启闭的常见故障及对策。     

V型滤池配水均匀性浅析

由于阻力和渠中水流速度的变化,V型滤池配水渠水面高程沿程变化,引起配水不均匀。为了提高配水均匀度,一种实用的方法是调整配水堰顶高程。基于水力学原理推导出配水渠内水面升高值的计算公式,为合理快捷调整配水堰顶高程提供依据。     

V型滤池反冲洗工艺过程节能优化研究

V型滤池持续有效过滤的关键是滤床的反冲洗。研究反冲洗后滤池浊度曲线的变化规律,通过改变反冲洗的周期与参数,在保证出水符合标准的前提下,结合阀门开度等指标,提出反冲洗工艺过程的最优气水比等控制参数,进而结合能耗数据确定反冲洗优化方案。研究结果表明,反冲洗工艺过程气水比约为2∶1时,在不同周期的浊度平均去除率最高,反冲洗效果最好。另外结合能耗数据推荐反冲洗优化方案为气冲强度6.12L/(s·m2),水冲强度2.88L/(s·m2),混合冲洗时间8min。     

淄博引黄V型滤池自动化控制系统分析

以淄博市引黄供水公司的V型滤池为例,系统介绍了V型滤池自控系统的硬件组成、网络结构、控制程序及系统功能,对V型滤池自控系统的设计和建设具有一定的参考意义。     

采用小阻力配水系统的V型滤池气密性试验研究

以信阳市湖东水厂V型滤池气密性试验为例,研究了采用小阻力配水系统V型滤池气密试验的必要性及试验方法。通过生产实际应用,提出了检验V型滤池气密性的操作方法。     

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.     

好氧颗粒污泥的形成机理及其影晌因素

全面地综述了国内外在好氧颗粒污泥方面的研究现状,包括好氧颗粒污泥的基本特征、颗粒化过程中的影响因素、形成机理及其微生物组成,以及在污水处理方面的优势。同时,对其未来的研究和发展趋势作了展望。     

Hygienization of municipal sludge in automatically operated chamber filter presses with thermal vacuum drying.

This paper presents the state of the art of thermal vacuum drying in chamber filter presses for unattended automatic operation. The achieved results are exemplified by the treatment of the two stage digested combined primary, chemical and biological sludge created by the VEAS concept for nutrient removal from municipal wastewater at VEAS. The water removal rate in each stage of the drying process is described, with comments on the low energy needs. The advantages of one-sided heating, the capacity and the drying potential are discussed. The hygienization potential of the process is demonstrated by the effect on thermostable coliform bacteria, Escherichia coli, salmonella, the spores of sulfite reducing anaerobic bacteria, f-specific bacteriophages, the seeds of the weed, wild oat, Avena fatua, and the parasite eggs of the potato cyst nematode, Globodera rostochiensis. A more complete paper with the VEAS-concept is found on the VEAS homepage (www.veas.nu).     

Impact of sludge retention time on sludge characteristics and microbial community in MBR

In this study, the impact of sludge retention time (SRT) on sludge characteristics and microbial community and the effect on membrane fouling in membrane bioreactor (MBR) was investigated. The results show that MBR with longer SRT has less fouling propensity, in agreement with other studies, despite the fact that the MBR with longer SRT contained higher MLSS and smaller particle size. However, much more soluble microbial products (SMPs) were released in MBR with shorter SRT. More slime on the membrane surface was observed in MBR with shorter SRT while sludge cakes formed on the membrane surface in MBR with longer SRT. The results show that SMP contributes to the severe fouling observed in MBR with shorter SRT, which is in agreement with other studies showing that SMPs were the major foulants in MBR. Under different SRTs of operation, the bacterial community structures of the sludge obtained by use of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) were almost identical, but those on the membrane surface differed substantially. It suggests that, although SRT has impact on sludge characteristics, it doesn't affect the microbial community in the suspension.     

Co-conditioning and dewatering of alum sludge and waste activated sludge.

Co-conditioning and dewatering behaviors of alum sludge and waste activated sludge were investigated. Two different sludges were mixed at various ratios (2:1; 1:1; 1:2; 1:4) for study. Capillary suction time (CST) and specific resistance to filtration (SRF) were utilized to assess sludge dewaterability. Relatively speaking, waste activated sludge, though of higher solid content, was more difficult to be dewatered than alum sludge. It was found that sludge dewaterability and settlability became better with increasing fraction of alum sludge in the mixed sludge. Dosage required of the cationic polyelectrolyte (KP-201C) for dewatering was reduced as well. It is proposed that alum sludge acts as skeleton builder in the mixed sludge, and renders the mixed sludge more incompressible which is beneficial for sludge dewatering. Implications of the results of the study to the sludge management plan for Taipei City that generates both alum sludge and waste activated sludge at significant amount are also discussed. The current sludge treatment and disposal plan in Metropolitan Taipei could be made more cost-effective.     

Mineralisation of hazardous organic compounds in a sludge reed bed and sludge storage.

Linear alkylbenzene sulphonates (LAS) and nonylphenolethoxylates (NPE) may be detrimental to the environment if spread in inappropriately large concentrations. Mineralisation of LAS and NPE in mesophilic digested sludge was observed during a 9-month monitoring programme where three separate treatment methods were investigated. Sludge was treated in a sludge reed bed under aerobic conditions, by storage in a container under anaerobic conditions, and by storage in a sludge pile turned over mechanically at intervals to improve the oxygen influx. Treatment in a sludge reed bed was shown to be effective. Mineralisation of 98% of LAS and 93% of NPE was observed. Only limited mineralisation occurred on the surface of the sludge stored in a container. A reduction of LAS and NPE of 90% and 43%, respectively, was observed in the sludge which was stored in a pile and frequently turned.     

用污泥沉降比指导活性污泥法运行的探讨

总结讨论了污泥沉降比在活性污泥法污水处理过程中与MLSS的关系和对活性污泥法处理效果的影响,分析其与季节变化的关系,指出污泥沉降比在预防污泥膨胀及维持曝气池稳定运行方面的作用,影响污水处理效果因素之间的关系,以及污泥沉降比在实际生产运行管理中的指导作用。     

臭氧氧化污泥工艺的剩余污泥零排放理论可行性研究

以臭氧氧化污泥工艺为模型,通过把曝气池产生的剩余污泥进行臭氧处理后,变成可生物降解的有机物,然后流回曝气池被微生物重新利用来实现污泥的零排放。从理论上研究了,只需要把H=3/(1+2S_e/S_a)倍的预计剩余污泥进行臭氧氧化处理,即把曝气池实际产生的剩余污泥进行臭氧处理,然后回流到曝气池进行生物降解,就可以实现剩余污泥零排放。臭氧氧化污泥工艺剩余污泥零排放的理论可行性,为剩余污泥零排放工艺的设计和运行提供理论支持。同时分析了许多成功的实例,进一步验证了理论。     

Application of ensemble H-infinity filter in aquifer characterization and comparison to ensemble Kalman filter

Though the ensemble Kalman filter (EnKF) has been successfully applied in many areas, it requires explicit and accurate model and measurement error information, leading to difficulties in practice when only limited information on error mechanisms of observational instruments for subsurface systems is accessible. To handle the uncertain errors, we applied a robust data assimilation algorithm, the ensemble H-infinity filter (EnHF), to estimation of aquifer hydraulic heads and conductivities in a flow model with uncertain/correlated observational errors. The impacts of spatial and temporal correlations in measurements were analyzed, and the performance of EnHF was compared with that of the EnKF. The results show that both EnHF and EnKF are able to estimate hydraulic conductivities properly when observations are free of error; EnHF can provide robust estimates of hydraulic conductivities even when no observational error information is provided. In contrast, the estimates of EnKF seem noticeably undermined because of correlated errors and inaccurate error statistics, and filter divergence was observed. It is concluded that EnHF is an efficient assimilation algorithm when observational errors are unknown or error statistics are inaccurate.     

Process performance and change in sludge characteristics during anaerobic digestion of sewage sludge with ozonation.

A new process configuration combining anaerobic digestion with ozonation, and operated at long SRT, was studied with the objective of on-site reduction in sludge quantity and improving biogas recovery. The process performance with respect to solid reduction efficiency and other important process parameters like accumulation of inorganic solids, changes in sludge viscosity and dewatering characteristics were evaluated from the data of long term pilot scale continuous experiments conducted using a mixture of primary and secondary municipal sewage sludge. Due to sludge ozonation and long SRT, high VSS degradation efficiency of approximately 80% was achieved at a reactor solid concentration of 6.5%. A high fraction of inorganic solid (>50%) consisting mainly of acid insoluble and iron compounds was found to accumulate in the reactor. The high inorganic content accumulated in the digested sludge did not, however, contribute to the observed increase in sludge viscosity at high solid concentration. The sludge viscosity was largely found to depend on the organic solid concentration rather than the total solid content. Moreover, higher inorganic content in the digested sludge resulted in better sludge dewaterability. For a quick assessment of the economic feasibility of the new process, an economic index based on the unit cost of digested sludge disposal to unit electric cost is proposed.