IWA Resource Recovery Cluster 污水资源回收最新汇编报告(1)
RECOVERY OF RESOURCES FROM WATER
There are different ways to categorize recovered resources from water.This report presents three main groups: water, energy and components, in which the latter is, among others, comprised of nutrients, chemicals and metals.
The technological synopsis of the report has been prepared as a means of providing a brief state of the art overview on technological aspects of resource recovery. Ideas on future trends, drawn from the IWA survey among others, conclude each section.
Numerous journal papers and books have been published describing the below mentioned technologies further in detail.
Furthermore, several excellent topic-based compendiums have been prepared, such as the Water Environment Research
Federation (WERF) nutrient recovery study which includes a technical overview of extraction techniques used for nutrient recovery. A book edited by Jimenez and Asano, Water Reuse - an International Survey of current practice, issues and needs provides agood overview of current status of water reuse and the book Water–energy interactions of water reuse edited by Lazarova, Choo and Cornel examines in-depth different linkages between water and energy.
第一部分-水
Water
One of the recovered resources from used water, traditionally termed ‘wastewater’, can be water in itself. Recovered water from used water is utilized for different purposes. The majority of water reuse projects worldwide are for agricultural irrigation. Municipal and public uses of water play an important role in total urban water use, and there are multiple successful cases worldwide where local water authorities have implemented water reclamation and reuse projects. In the industrial sector, cooling is the most common reuse application, and power plants worldwide have adopted large-scale water reuse schemes. Increasing interest in using recovered water has further been noted for ground water recharge and potable reuse.
根据不同用途制定相应的污水处理方案 Treatment of Used Water Facilitating a Broad Range of Reuse Options
More than 99.5% by mass of used water consists of water, representing an enormous pool of recoverable resources. With treatment processes available today, used water can be treated to the extent required for any given reuse purpose. An increased level of treatment of used water can result in higher water quality and therefore reduced risks during human exposure, for both potable and non-potable usage.
Traditionally, used water treatment can be defined as primary, secondary, and advanced. In primary treatment a portion of suspended solids and organic matter is removed. Due to its poor quality, nouse of water is recommended after this treatment stage. Secondary treatment removes biodegradable organic matter and suspended solids, commonly followed by disinfection. Groundwater recharge, surface irrigation and industrial cooling processes are some examples of uses for this level of water quality. Advanced treatment, which targets removal of nutrients, organic constituents as well as suspended and dissolved solids, broadens the pool of alternatives for the usage of reclaimed water. Toilet flushing, food crop irrigation and recreational impoundment are examples of what such water can be used for in terms of non-potable purposes. Water that is treated by advanced processes can also be utilized for potable reuse. Various treatment combinations representing multiple barriers against microbial and chemical contaminants have been established worldwide. Most commonly the seinclude combinations of advanced oxidation processes, activated carbon and biofiltration or integrated membranes systems such as ultrafiltration followedby reverse osmosis. The first plant for indirect potabl e reuse was established in the Montebello Forebay, California in 1962 while Windhoek, Namibia inaugurated the first direct pot able reuse plant in 1968. In Europe a first major project in this context was the up-cycling of treated sewage in Koksijde,Belgium to obtain drinking water.
For the domestic sector, it has been proposed that the concept of the current approach of dealing with sewage, which is mainly based on dissipating the non-aqueous molecules present in water, could be reversed entirely by maximizing on reuse. A suggested treatment method is to provide an up-concentration at the front of the treatment plant and subsequently process a minor flow to be dealt with in terms of recovery of materials and a major flow from which clean water can be obtained.
新趋势 New Trends
Increasing water scarcity and growing populations have triggered a growing use of unconventional water resources such as reclaimed water. One researcher in IWA’s survey predicts that recycled and purified water is a future trend for resource recovery. Another respondent further anticipates that the portion of reused water in freshwater resources will increase in years to come. Due to the impacts of severe droughts, recent developments in USA and southern Africa have led to an increase in favoring direct potable reuse uses. In such applications, highly treated water is either fed directly into a drinking water distribution system or into a raw water supply of a conventional drinking water plant. This procedure is carried out without the water passing through an environmental buffer such as a surface water reservoir or groundwater aquifer. In addition, there is a growing recognition for de facto potable reuse in many regions of the world where used water discharge impacts downstream drinking water abstractions. These trends,combined with decades of experiences with indirect potable reuse schemes and improved treatment and monitoring strategies, are likely to support a growing interest in establishing direct potable reuse schemes.
There is also an increasing recognition for water-energy interactions in water reuse, resulting in more energy-efficient treatment schemes, such as decentralized reclamation approaches which reduces the need to pump reclaimedwater over a long distance and tailoring water qualities to local needs that are fit for purpose.
未完待续
Authors: Katrin Eitrem Holmgren, Hong Li, Willy Verstraete and Peter Cornel
本文节选自IWA Resource Recovery Cluster的最新汇编报告 State of the Art Compendium Report on Resource Recovery from Water。更多内容，请访问IWA网站: http://www.iwa-network.org/cluster/resource-recovery-from-water-cluster
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