城市污水处理厂运行决策支持系统(WWTP ODSS(R))的介绍和应用

介绍了基于经验知识和活性污泥数学模型ASMs的城市污水处理厂运行决策支持系统(WWTP ODSS(R))的开发历程、主要结构功能以及应用情况,重点介绍了ODSS中专家系统和模拟系统在北京市清河污水处理厂的应用实例.ODSS系统集预警、故障诊断、过程模拟和预测等多种功能于一体,通过系统内置的溶解氧、回流比和排泥量等单元控制模块实现了前馈-反馈控制策略,为污水处理厂的运行和控制提供有力的指导和支持.     

Dynamic monitoring system for full-scale wastewater treatment plants.

This paper proposes a new process monitoring method using dynamic independent component analysis (ICA), ICA is a recently developed technique to extract the hidden factors that underlie sets of measurements, whereas principal component analysis (PCA) is a dimensionality reduction technique in terms of capturing the variance of the data. Its goal is to find a linear representation of non-Gaussian data so that the components are statistically independent. PCA aims at finding PCs that are uncorrelated and are linear combinations of the observed variables, while ICA is designed to separate the ICs that are independent and constitute the observed variables. The dynamic ICA monitoring method is applying ICA to the augmenting matrix with time-lagged variables. The dynamic monitoring method was applied to detect and monitor disturbances in a full-scale biological wastewater treatment (WWTP), which is characterized by a variety of dynamic and non-Gaussian characteristics. The dynamic ICA method showed more powerful monitoring performance on a WWTP application than the dynamic PCA method since it can extract source signals which are independent of time and cross-correlation of variables.     

Aerobic granular sludge: a promising technology for decentralised wastewater treatment.

In order to evaluate the characteristics of aerobic granular sludge, a sequencing batch reactor, feeding with synthetic wastewater at the organic loading rate of 8 kg COD/m3 d, was employed on the laboratory scale. Granules occurred in the reactor within 1 week after the inoculation from conventional flocculent sludge. Aerobic granular sludge was characterised by the outstanding settling properties and considerable contaminates removal efficiencies. The SVI30 values were in the range of 20 to 40 ml g(-1). However, the sludge volume index of short settling time (e.g. SVI10--10 min) is suggested to describe the fast settling properties of aerobic granular sludge. The potential application in the decentralised system is evaluated from the point view of footprint and high bioactivity. The occurrence of sloughing, resulting from the outgrowth of filamentous organisms, would be responsible for the instability of aerobic granules. The starvation phase should therefore be carefully controlled for the maintenance and stability of aerobic granular sludge system.     

Model-based knowledge acquisition in environmental decision support system for wastewater integrated management

The main goal of the Water Framework Directive is to achieve good chemical and ecological status of water bodies by 2015. The implementation of integrated river basin management, including sewer systems, wastewater treatment plants and receiving water bodies, is essential to accomplishing this objective. Integrated management is complex and therefore the implementation of control systems and the development of decision support systems are needed to facilitate the work of urban wastewater system (UWS) managers. Within this context, the objective of this paper is to apply integrated modelling of an UWS to simulate and analyse the behaviour of the 'Congost' UWS in Spain, and to optimize its performance against different types of perturbations. This analysis results in optimal operating set-points for each perturbation, improves river water quality, minimizes combined sewer overflows and optimizes flow lamination from storm water tanks. This is achieved by running Monte Carlo simulations and applying global sensitivity analysis. The set-points will become part of the knowledge base composed of a set of IF-THEN rules of the environmental decision support system being developed for this case study.     

Economic considerations and decision support tool for wastewater reuse scheme planning.

The reuse of upgraded wastewater for beneficial uses is increasingly adopted and accepted as a tool in water management. However, funding of schemes is still a critical issue. The focus of this paper is on economic considerations of water reuse planning. A survey of pricing mechanisms for reclaimed water revealed that most schemes are subsidised to a great extent. In order to minimise these state contributions to the implementation and operation of reuse projects, their planning should identify a least cost design option. This also has to take into account the established pricing structure for conventional water resources and the possibility of gaining revenues from reclaimed water pricing. The paper presents a case study which takes into account these aspects. It evaluates different scheme designs with regard to their Net Present Value (NPV). It could be demonstrated that for the same charging level, quite different amounts of reclaimed water can be delivered while still producing an overall positive NPV. Moreover, the economic feasibility and competitiveness of a reuse scheme is highly determined by the cost structure of the conventional water market.     

An integrated system to remote monitor and control anaerobic wastewater treatment plants through the internet.

The TELEMAC project brings new methodologies from the Information and Science Technologies field to the world of water treatment. TELEMAC offers an advanced remote management system which adapts to most of the anaerobic wastewater treatment plants that do not benefit from a local expert in wastewater treatment. The TELEMAC system takes advantage of new sensors to better monitor the process dynamics and to run automatic controllers that stabilise the treatment plant, meet the depollution requirements and provide a biogas quality suitable for cogeneration. If the automatic system detects a failure which cannot be solved automatically or locally by a technician, then an expert from the TELEMAC Control Centre is contacted via the internet and manages the problem.     

污水处理厂的安全自控系统

随着污水处理行业的快速发展,污水处理厂安全越来越成为工艺稳定运行的关键.针对控制系统本身的安全性及对相应控制设备和工艺的安全性,提出了污水处理厂的安全自控系统原则.并以实际自控系统为例,说明安全自控系统的组成及实现.     

Semi-intensive treatment plants for wastewater reuse in irrigation.

Semi-intensive technologies are a middle term between intensive ones (e.g., activated sludge with a retention time of hours) and extensive ones (e.g., stabilization ponds with a retention time of several weeks). The most common semi-intensive configuration used in Israel is made of anaerobic ponds followed by aerated lagoons. These small low-energy units remove about 75-80% of the BOD and are followed by wastewater reservoirs for storage and complementary treatment. The reduction in loading allows a flexible operation of the reservoirs for the removal of other pollutants, while providing storage capacity to cope with the changes in water demand for irrigation during the year. In schemes for wastewater reuse in irrigation, this lay-out has proved to be low-cost, low-energy, flexible, reliable and efficient. Variations of this basic configuration are the use of UASB reactors instead of anaerobic ponds, aerated lagoons in series or low-rate trickling filters instead of aerated lagoons, constructed wetlands or rock-filters for algae removal, etc. Semi-intensive technologies use less energy than intensive ones, and less land than extensive ones. They can remove as much BOD as intensive ones, and as much pathogens and refractory pollutants as extensive ones. They release no or very small amounts of sludge.     

Fault detection for control of wastewater treatment plants.

Interest in real-time model-based control is increasing as more and more facilities are being asked to meet stricter effluent requirements while at the same time minimizing costs. It has been identified that biological process models and automated process control technologies are being used at wastewater treatments plants throughout the world and that great potential for optimising biotreatment may exist with the integration of these two technology areas. According to our experience, wastewater treatment plants are indeed looking for ways to successfully integrate their modelling knowledge into their process control structure; however, there are practical aspects of this integration that must be addressed if the benefits of this integration are to be realised. This paper discusses the practical aspects of monitoring, filtering and analysing real sensor data with an aim to produce a reliable real-time data stream that might be used within a model-based control structure. Several real case study examples are briefly discussed in this paper.     

Performance indicators for wastewater treatment plants

The Swedish Water & Wastewater Association has operated a web-based system, VASS, for the collection and compilation of key data from the Swedish water utilities since 2003. The VASS system will now be expanded to include data on operation of individual wastewater treatment plants (WWTP). The objective is to provide performance indicators (PIs) for performance and economy and the use of resources such as energy, chemicals and manpower. A set of PIs has been developed that also includes explanatory factors to compensate for differences in the condition of operation between plants. This paper discusses the data required for the calculation of PI but also for explanatory factors, quality checks and for plant operation context. The discussion is based on the experiences from a test round with the participation of 24 WWTP.     

A guideline for simulation studies of wastewater treatment plants.

A guideline for simulation studies of wastewater treatment plants is proposed. The aim of the HSG-guideline is to define a reference quality level that helps to make the results of simulation studies comprehensible and comparable and therefore increases the quality and reliability of mathematical modelling in wastewater treatment. The paper gives a summary of the HSG-guideline, written by a group of university members from Germany, Austria and Switzerland.     

Evaluating the application of a decision support system in identifying adequate wastewater treatment for small communities. A case study: the Fluvia River Basin.

The identification of adequate wastewater treatment for small communities is a complex problem since it demands a combination of data from different sources, such as aspects of the community and landscape, the receiving environment and the available wastewater treatment technologies. The Catalan Water Agency (Agència Catalana de l'Aigua) considered using an EDSS (Environmental Decision Support System) as a tool to help water managers select the most adequate treatment for the urban wastewater of nearly 3,500 small communities in Catalonia (Spain). From that moment, EDSS was applied to all the river basins in Catalonia. In this paper the authors present the results obtained for the 76 small communities located in one of these river basins: the Fluvia River Basin. The characteristics of the community used in the reasoning process of the EDSS, the list of selected wastewater treatment alternatives, the technical environmental justification for the selected treatments and the reasons for discarding, favouring or disadvantaging them are presented. Finally, some results for the Fluvia River Basin are compared with those obtained in other Catalan river basins with different characteristics in order to evaluate which are the significant features in identifying adequate wastewater treatments.     

Toxicity of domestic wastewater pH to key species within an innovative decentralised vermifiltration system.

The development of innovative decentralised wastewater treatment systems is pertinent to environmental sustainability. However for their appropriate use they require significant research and design to ensure they can be relied upon in the future and in most cases they have received less attention and research than large-scale sewage systems. This study assessed the likelihood of biological inhibition and disruption from pH to key species for vermifiltration. The test firstly assessed the buffer capacity of a vermicompost + manure media finding it had a relatively high buffering capacity for pH. The toxicity after the buffer capacity experiment showed that the species would survive between pH levels of 6.2 and 9.7. At the higher and lower pH levels however the survival of juveniles was impaired, probably due to their ability to uptake greater amounts of soluble salts and inability to regulate them. Overall the study showed that the tolerance of the key vermifiltration species to pH was far less than their survival as previously proposed and further research assessing their long-term population dynamics in a vermifiltration system with pH is warranted.     

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.     

Computational intelligence-based optimisation of wastewater treatment plants.

Methods of computational intelligence (CI), especially fuzzy control and neuronal networks, are used for controlling and optimising of wastewater treatment plants. Areas of application are the control of sludge water dosage, of phosphate elimination by optimal precipitant dosage as well as an optimal aeration in the nitrification zone. In two municipal wastewater treatment plants with 60,000 and 12,600 person equivalents the controllers have been installed and optimised and they have been in operation for several years. Results of operation of the plants are presented in comparison to previously used classical control. Performance increased significantly and the outflow values could be kept securely below the government requirements without increase of the energy consumption. Peak loads in the inflow were eliminated in the plant and did not increase outflow concentrations. Results of operation for more than three years clearly show that the CI controller is a cost-efficient method for a sustainable rise of performance in municipal wastewater treatment plants.     

New compact scrubber for odour removal in wastewater treatment plants.

This work presents the performances of a new odour scrubber. The reactor is packed with a new structure which enables co-current operations at high gas velocities. Energy consumption and removal efficiency of sulphur compounds by oxidative alkaline scrubbing were studied. The influence of both superficial gas (U(SG)) and liquid (U(SL)) velocities, ranging from 5.6 to 28 m.s(-1) and 0.016 to 0.055 m.s(-1) respectively, were quantified. Thus, the range of 0.5 to 5 liquid-to-gas mass ratio (L/G) was studied. A comparison has been made with a previous study on static mixers (SM) and with classical random packed towers (PT). It has been shown that superficial liquid and gas velocities have a significant influence on these parameters. Hydrogen sulphide (H2S) abatement reached values up to 99%. As concerns methylmercaptan (CH3SH), the maximal removal efficiency was 87%. As a result, if well scaled-up, our reactor can be a small single stage efficient apparatus for the elimination of low concentrations of sulphur compounds as H2S and CH3SH in high flow rates of polluted gas effluents.     

Automatic control and remote monitoring system for biological nutrient removal on small wastewater treatment plants in Korea.

Many small-size wastewater treatment plants in Korea's rural communities are designed to remove organic and suspended matter only, and they generally show a large fluctuation in the influent loading compared to municipal wastewater treatment plants (MWWTPs). They also have no professional engineers stationed for efficient operation against mechanical breakdown. For those reasons, the wastewater treatment plants have low efficiency in treatment of nitrogen and phosphorus as well as organic matter. In order to solve those problems, this study developed an automatic control system and RMS (remote monitoring system), which can keep efficiency stable despite any change in the small plants' loading rates and are capable of removing nutrient materials such as nitrogen or phosphorus. According to the results of the Experimental SBR system of the automatic control program, complete nitrification was made under oxic conditions and denitrification occurred as NO3-N concentration decreased by 0.5 mg/l in anoxic conditions and excellent nitrogen removal efficiency was seen generally. The Experimental SBR system created "phosphate release and uptake" effectively and displayed phosphate-removing efficiency up to more than 80% as the concentration of effluent was kept low by 0.4 mg/l. RMS developed in this study transmits a plant's data and operation states to clients in remote locations in real-time interval through the Internet. Therefore, although you are in a remote location, it allows you to see if a plant is properly operated or there is any breakdown.     

Steroid estrogens in primary and tertiary wastewater treatment plants.

The concentrations of two natural estrogens (estrone (E1) and Estradiol (E2)) and one synthetic progestin (Ethinylestradiol (EE2)) were measured for different unit operations in an advanced sewage treatment plant and in a large coastal enhanced primary sewage treatment plant. The average influent concentration to both plants was similar: 55 and 53 ng/L for E1 and 22 and 12 ng/L for E2 for the advanced and enhanced primary STPs, respectively. The activated sludge process at the advanced STP removed up to 85% and 96% of E1 and E2, respectively. The enhanced primary sewage treatment plant was mostly ineffective at removing the steroids with only 14% of E1 and 5% of E2 being removed during the treatment process. EE2 was not been detected during the study period in the influent or effluent of either STP. The difference in the observed removal between the two plants is primarily linked to plant performance but the extent to which removal of steroid estrogens is due to bacterial metabolism (i.e. the advanced STP) rather than adsorption to the bacterial biomass remains unclear. The poor removal observed for the coastal enhanced primary STP may have implications for the receiving environment in terms of a greater potential for abnormal reproductive systems in marine animals, particularly if discharges are into large bays or harbours where flushing is limited.     

Scalable mobile information system to support the treatment process and the workflow of wastewater facilities.

In order to support the operation of wastewater systems and the workflow of sewage systems an application for demonstration has been developed to show exemplarily how a mobile information system can be transferred into practice and used by the staff. The paper presents a scalable information visualisation system, which can be used with mobile devices. The regarded information data does not only include process data, but also general information about buildings and units, work directions, occupational safety regulations as well as instructions of first aid in case of a work accident. This is particularly appropriate for the use in remote facilities. The implementation is based on but not limited to SQL, JSP and HTML.