绍兴污水处理厂污泥处理工程改扩建设计

介绍了绍兴污水处理厂污泥处理工程的改扩建设计,设计中对现有污泥处理脱水构筑物及设备进行了改造,解决了其污泥脱水性能较差的问题,充分发挥了现有设施的处理能力,污泥预处理能力达到350 tDS/d(83%含水率污泥为2 059t/d),新建处理能力为370 tDS/d(80%含水率污泥为1 850t/d)的污泥处理设施,全厂污泥全部处理后外运处置.     

Environmental Implications of Incineration and Other Advanced Sludge-Treatment Processes

In the UK, there is a strong trend towards more thermal processing of sludge with energy recovery or advanced treatment of sludge, in preparation for use in agriculture or other outlets. This has resulted from (a) the loss of the sea-disposal outlet and (b) pressure to improve the microbiological quality of recycled biosolids to land. In 1996–97, incineration accounted for 8% of sludge, and this figure is expected to increase to 21% by the year 2005. During this period, the annual production of sludge is expected to increase from 1.12 million tDS to 1.47 million tDS. More sludge will be treated by processes such as thermal drying, thermophilic digestion, prepasteurisation and mesophilic anaerobic digestion, lime treatment and other advanced options such as gasification. These developments apply across the EU and are likely to be driven forward by the impending revision of the 'sludge to land'Directive. The paper considers the environmental implications of these developments in terms of energy usage and recovery, air and water quality, greenhouse-gas emissions, effects on contaminants, and the quality of products or residues.     

Impact in Scotland of UK and EC Sewage Legislation

The EC Directive (91/271/EEC) concerning urban waste water treatment has far-reaching financial and technological implications for local authorities in Scotland which are responsible for sewerage. Increased capital consent limits and additional financial assistance from central government are essential if the requirements of the legislation are to be met.
Although the Directive is welcomed in general terms, the sections of the legislation dealing with the identification of sensitive waters and the provision of primary treatment for coastal discharges to less sensitive waters are of limited environmental significance in Scotland.
The elimination of sewage sludge disposal at sea will create severe difficulties for Scottish authorities as a high percentage of sewage sludge is currently disposed of at sea. Each of the main alternative disposal options presents environmental, financial and technical problems and, in the case of incineration, the certainty of widespread unpopularity with the public.     

Evaluation and Development of a Thermophilic Aerobic Digester at Castle Donington Sewage-Treatment Works

An investigation into the practicality of thermophilic aerobic digestion has been in progress at Castle Donington since 1989. The work has been carried out in a glassed steel insulated digester of 123 m³ capacity. Both auto-entraining and blower-assisted venturi systems have been evaluated.
Both aeration systems were able, under favourable conditions, to remove at least 50% of the sludge COD. It was found that the additional flexibility of the blower venturi combination was necessary to accommodate crude sludges varying from 2% to 12% dry solids.
Originally the plant was intended to operate at above 55C with a 10-day retention period. In practice retention periods at this temperature have been at least 15 days. The process has proved relatively susceptible to inhibition and requires the air supply to be closely matched to the load.
The revenue costs have been, at best, around 47.3/tDS. This is competitive with small-scale anaerobic digestion, but not with the large digestion centre approach widely used in the UK. Unless pasteurization becomes a requirement for agricultural disposal, thermophilic aerobic digestion is unlikely to find wide use in this country.     

上海市污泥处理处置专项规划简介

城市污泥处理处置技术随着城市化进程的加快越来越受到重视.结合上海制定城市污泥处理处置专项规划的经验,认为在进行技术方案研究的同时,应充分了解整个服务范围内的污泥数量、污泥性质,并对污泥处置的潜在出路进行研究,继而确定处理处置场所的规划,提出实施处理处置的准入条件和法规政策.     

Hazardous Waste: Future Consideration

In most industries the goods and money move in opposite directions, but in waste management the goods and money travel in the same direction. Consequently to the customer, quality of goods and service might be measured only by price. However, customers are now becoming more sensitive to factors such as environmental quality. They are also becoming aware of the range of disposal options, together with the names of the companies which operate these disposal or treatment sites. Essentially the options are: recyling and recovery, sea disposal, landfill, physico-chemical treatment, solidification, biological treatment and thermal destruction. The Control of Pollution Act 1974 requires that all landfill sites and treatment centres are licensed by the waste disposal authority. These authorities are obliged to act in the public interest, and hence there is a complex interaction of science and politics. This situation often gives rise to localized opposition to facilities which are needed by the community. The UK disposes of 83 per cent of its potentially difficult wastes to landfill whilst Holland disposes of 52 per cent via this route. The cost of disposal varies throughout Europe but, in general, prices in the UK are lower than in Europe, which has led to the importation of wastes from the continent. Economics applies to the waste-disposal industry as much as any other industry, therefore facilities are supplied in response to demand. Price alone will not always be adequate in obtaining the ‘best practical environmental option’. disposal the goods and the money go in the same direction, i.e. to the waste management contractor. This at first sight may not seem important until it is realized that the major control upon the quality of a service is, in fact, the satisfaction with the goods and service which the customer receives. In most cases it is sufficient that the customer disposes of the waste material in a legal manner. However, the judgement of quality of disposal could be of little consequence to him. The factors that concern a customer when he chooses a service include the price, the quality of service, market presentation and reputation. These factors apply in the waste management industry, but the difficulty for the customer is to judge the quality of the service and the market presentation or, more correctly in this case, the quality of operation of the waste contractor. If the latter two factors become difficult to judge, the price becomes a critical factor. This leads to a low standard of operation in the business where price competition becomes more important than the quality of the service. Companies are looking not just for the cheapest legal option but for the best option and what has been referred to as the ‘best practical environmental option’. In the UK the vast majority of hazardous waste disposal is carried out by private-sector companies. Therefore it is essential that the Government sets the correct framework, and that an examination is carried out as to whether the framework is satisfactory and whether it achieves the needs of the Government.     

Development of the Sludge Thermal-Drying Option for South West Water

Sewage-sludge production in South West Water is predicted to more than double, to about 50000 dry tonnes per annum, by the turn of the century. Staff of South West Water Services have carried out a strategic review of sludge utilization and treatment options, and have developed a strategic planning computer model to assist in the financial evaluation of the many options which are available. The strategy allows for the provision of new raw sludge thermal-drying facilities for the anticipated increase in sludge production.
Trials were carried out with an indirect dryer system to develop and investigate the operational issues and use of the dried raw product. The initial trial produced a fluffy, low-density material with poor storage and handling characteristics, apparently associated with the high-fibre content of the sludge. The process has been modified to include pelletization.     

Potential for Sewage Sludge Co-Combustion in the UK Based on German Experience

Increasingly strict legislation, escalating costs and external pressures are causing the water industry to look for alternative strategies to agricultural recycling for the disposal of biosolids. Although the development of the 'safe sludge matrix'has encouraged agricultural recycling, negative press has hampered this outlet and public perception is seen as a major threat. Accordingly, many water companies are looking towards thermal-reduction technologies and have invested in thermal dryers and sludge incinerators; however, such technology has high capital costs and complex maintenance and operator requirements. An alternative method, i.e. co-combustion, is becoming more popular in mainland Europe. Unlike incineration/drying, the capital expenditure is low and operator/maintenance risks are minimised.
This paper (i) discusses a case study in which 40 000 dry tonnes of sludge per annum have been successfully combusted since 1996, and (ii) explores how this experience could be applied in a UK situation.     

Compensation and negotiation in the siting of hazardous-waste facilities

The transport and storage/disposal of hazardous materials is clearly of fundamental importance to the continuing economic and social well-being of the industrialized world. This is also an extremely difficult area for public policy, since it involves potentially large risks, and unresolved technical and economic uncertainties make informed consensus among affected stakeholders difficult. This paper will briefly review current policy options for siting storage/disposal facilities for toxic wastes. Emphasis will be on policies which are economically efficient and which provide incentives to various stakeholders to participate constructively in negotiating equitable risk-sharing solutions to the problems of interest. In particular, incentives based on compensation and insurance will be discussed in light of experience from several countries.     

Significance and behaviour of heavy metals in waste water treatment processes II. Sludge treatment and disposal

The literature concerning the significance and behaviour of heavy metals in sewage sludge treatment and following sludge disposal is reviewed. Particular attention is given to metal form during anaerobic digestion and following sludge disposal to agricultural land and to sea, and the influence of metal form on toxicity. It is evident that anaerobic digestion results in a strong association between sludge particulates and heavy metals due to the formation of inorganic precipitates, organo-metallic interactions and by association with the biomass. Toxic inhibition of anaerobic digestion by metals is concluded to be a direct result of the free metal ion concentration and thus mechanisms designed to reduce metal toxicity are based on artificial modification of heavy metal speciation in the digester.Guidelines and legislation designed to limit the application of sludge to agricultural land and the disposal of sludge to sea are reviewed and discussed. Following the application of sludge to agricultural land significant changes occur in heavy metal speciation, which ultimately determine metal availability to plants and potential contamination of groundwaters. Guidelines for application to land currently take limited account of metal form, although the importance of metal speciation is being recognised. Sludge disposal to sea has received relatively little attention with efforts being directed towards monitoring rather than more fundamental research. However, it is apparent that significant heavy metal solubilisation may occur following sludge discharge to the marine environment.It is concluded that sludge disposal to agricultural land and sea, which are increasingly becoming subject to more stringent international pressures, should take account of the ultimate forms of heavy metals in the receiving environment and that a more unified approach should be adopted in the formulation of standards for all forms of sludge disposal.     

Sewage Sludge Production, Treatment and Disposal in the European Union

Sludge production and disposal are entering a period of dramatic change, driven mainly by EC legislation. The urban waste water treatment Directive will result in at least 50% more sludge being produced by the end of 2005 and, during the next decade, sludge disposal to all the established outlets could become increasingly difficult or, in the case of sea disposal, will become illegal. The challenge facing the members of the European Union is how to (a) maintain cost-effective and secure methods of sludge disposal and (b) engender public confidence in all disposal and recycling options. What is required is not so much innovative technology, although this may be essential, but more innovative attitudes and approaches to promotion and defending existing outlets.
This paper describes the likely pattern of sludge production, treatment and disposal which will emerge during the implementation of recent EC directives and other national policies in Europe, and focuses on the areas and issues which require innovative approaches.     

Carbon dioxide capture and geological storage: research,development and application in Australia

Projections of world energy demand indicate increasing use of fossil fuels, especially coal. Because of this there is interest in using carbon dioxide capture and storage technologies as a mitigation option, particularly in Australia because of its dependency on fossil fuels for electricity generation. Research in Australia into capture options includes post-combustion capture (PCC), integrated gasification combined cycle (IGCC) and oxyfuels combustion. Separation technologies being investigated in Australia include solvent absorption, membranes, adsorption and cryogenics, with particular emphasis on bringing down costs. Australia appears to have abundant geological storage capacity, particularly in saline formations and to a much lesser extent in depleted oil and gas fields. Storage in coal systems has potential but more research and development is needed. Australia has the opportunity to use low-emission hubs in order to bring down costs. A major study of this concept for the Latrobe Valley of Victoria, based on 50 million tonnes per annum of CO2 emissions, is encouraging. A key concept for taking CO2 capture and geological storage forward is demonstration and commercial deployment. Australian projects are proposed for PCC and oxyfuels combustion. A significant geological storage project has started in the Otway Basin, with CO2 injection scheduled to commence in mid-2007. The coal-to-liquids Monash Project could involve up to 10 million tonnes CO2 per annum, with injection into the offshore Gippsland Basin. The most advanced commercial project is the LNG Gorgon Project, comprising about 3 million tonnes per annum. Through current R&D momentum and the likelihood of a number of major commercial-scale projects, Australia could become an early mover in the application of carbon dioxide capture and geological storage.     

Preliminary investigation of the mercury saturation in the Baltic Sea winter surface water

A new experimental measuring system for the total gaseous mercury saturation in the sea surface water has been developed. The technique applied to the system is based on equilibrating water-air mercury partial pressures at the air-sea interface. First data using this system were collected in the Baltic Sea on 13-22 January 2000. Measurements were completed from the research vessel 'Alexander von Humboldt' on the way from the Gotland Sea to the Mecklenburg Bight. In general the results showed domination of supersaturated winter sea surface waters with respect to gaseous mercury. Two areas with distinctly elevated mercury saturation were found: one in the east-west shipping route, south of Bornholm, where the equilibrated gaseous Hg content of water was approximately 9.2-fold higher, and another over the ammunition disposal region south-east of Hoburgs Bank, where the Hg content of water was approximately 3.8-fold higher than that in air. In general, the data indicate that the south-western Baltic Sea, and in particular both maritime areas identified with elevated mercury saturation, can emit gaseous mercury from surface waters into the atmosphere and contribute to long-range atmospheric transport.     

A Sludge Disposal Strategy for Dumfries and Galloway Regional Council

The Dumfries and Galloway Regional Council's largely rural statutory area extends to 6370 km², with a population of 146 000. During 1988 the Council, mindful of impending legislation likely to affect existing sludge disposal outlets, particularly those to agricultural land, commissioned a detailed study into all aspects of sewage sludge production, treatment, storage and disposal. The prime aim of the study was the production of a regional sludge disposal strategy. Consideration was given to five different options of sludge disposal.     

'To Pump or Not to Pump' Cost-Benefit Analysis of Future Environmental Management Options for the Abandoned Durham Coalfield

Deep mining activity has totally ceased in the Durham coalfield, and withdrawal of the regional dewatering scheme is being contemplated. Consequent groundwater rebound is expected to have severe and expensive environmental consequences, which could only be entirely avoided through indefinite pumping. However, continued pumping is expensive, at about $1 million/annum. The options of either abandoning or continuing pumping have differing time streams of future costs and, consequently, direct comparison of the expenditures involved is difficult. Both options are therefore analysed using economic evaluation criteria in order to determine the lowest cost alternative for the future. The overall outcome of the economic analysis, using both net present value and equivalent annual cost criteria, demonstrates that the option of continued pumping is less expensive than the option of abandoning pumping in all cases.     

超高层建筑施工中氨气抑制的数值模拟

针对超高层建筑施工中典型空气污染物氨气,运用CFD方法构建武汉中心三维立体模型,模拟标准k ε条件下自然通风和机械通风2种抑制措施对氨气浓度整体影响效果并确定其影响进深。结果表明:稳态下机械通风对降低模型整体氨气浓度效果有限,单个送风口沿送风方向影响进深约为6.1 m,垂直于风速方向约为1.2 m,且送风口影响进深随风速变化极小;自然通风对降低模型整体氨气浓度效果明显,进风口对氨气浓度影响进深约为17.5 m,随高度增加逐渐递增的进风速度在通风前15 s对氨气浓度影响明显,稳态时风速增加自然通风影响进深增加有限;施工中可主要采用自然通风抑制氨污染,幕墙封闭后可利用机械通风并辅以导风板等设施提高机械通风影响效果。     

The Management of Sediment in Reservoired Catchments

The rates of sedimentation in Yorkshire reservoirs are high for the UK but low compared with those reported globally. Whilst not likely to jeopardize supply, the behaviour and properties of reservoir sediments have implications for the quantity and quality of the water.
Data suggest that the use of control and diversion structures reduces average sedimentation by 53m³/km² per annum in the case of residuum lodges, and also modifies the nature of the sediment considerably, tending to allow the finer, organic particles into the reservoir. Trapping may be minimized by the diversion of high flows where such facilities exist, or by maintaining water levels at the maximum possible in supply reservoirs.
Management strategies to reduce sedimentation would, in many cases, require fairly simple routine maintenance of existing structures. The short-term cost of discarded water must be weighed against the longer-term benefits of improved quality and reservoir capacity.     

The Management of Potable Water Treatment Sludge: Present Situation in the UK

This paper details the results of a survey of UK potable water supply organisations, which was undertaken in 1998 on behalf of UK Water Industry Research. An extrapolation of the data indicated that, in 1997, about 131 000 tDS of water-treatment works sludge were produced in the UK. The relevant methods and associated costs are reported. A number of companies are using, or developing, novel waste-management methods for water-treatment works sludges, such as incorporation into bricks and spreading on agricultural land, and these are discussed.     

Side-Stream Treatment of Raw-Sludge Liquors using Activated Sludge: Pilot Investigations and Full-Scale Design Rationale

The end of sludge disposal at sea in 1998 will lead to increased volumes of sludge requiring treatment and disposal. Accordingly, there will be further quantities of high-strength liquors arising from sludge thickening and dewatering processes, and additional treatment capacity will therefore be required at treatment works.
This paper describes a three-year project to develop a dedicated side-stream treatment process for the treatment of raw-sludge liquors at Knostrop sewage-treatment works (Leeds) based on the activated-sludge process. Large pilot-scale trials are described which assisted in the construction of simple process design models for full-scale design. Together with additional pilot-scale aeration testing and modelling, a cost model for a full-scale plant was developed, allowing the lowest whole-life cost plant, based on 'net present cost'analysis, to be specified.     

Treatment and Disposal of Sewage Sludge in the Mid-1990s

The paper reviews the current methods of sludge technology, and compares them with those discussed by Ashton in 1904. The paper also plots the development of some of the current technology over the last century, particularly those methods of treatment which were mentioned by Ashton but were not in existence at the time.
The 1990s have been a most interesting era, and have probably seen more changes in sludge technology than any other decade this century. The most significant impact will be due to the cessation of the sea disposal route which, at the beginning of the 1990s, was used for about 30% of the total sludge production in England and Wales and approximately 76% of the total sludge produced in Scotland.