ISO 23056:2020 pdf free download – Water reuse in urban areas一 Guidelines for decentralized/ onsite water reuse system一Design principles of a decentralized/ onsite system.
With economic development, climate change, rapid urbanization and increases in population, water has become a strategic resource especially in arid and semi-arid regions. Water shortages are considered as one of the most serious threats to the sustainable development of society. To address these shortages, reclaimed water is increasingly being used to satisfy water demands that do not require potable water quality. This strategy has proven useful in increasing the reliability of long-term water supplies in many water-scarce areas. The applications of reclaimed water depending on the volumes of reclaimed water available include restricted or unrestricted irrigation, industrial uses, toilet and urinal flushing, firefighting and fire suppression, street cleaning, environmental and recreational uses (ornamental water features, water bodies’ replenishment, etc.) and car washing.
While centralized water reuse facilities have been widely implemented under different ownership and management structures, there is also a need to develop decentralized/onsite water reuse systems in cost-effective and resource-efficient ways, which can improve flexibility and convenience. Depending on the size and scope of the system, private and community owned systems can increase the flexibility of the system to the needs of the owner(s). Decentralized/onsite water reuse systems have the advantage that they can be installed for a short-term when needed and have a lower cost than centralized systems due to sewers systems large investments. Moreover, they allow the local reuse of water and therefore increase water productivity. Compared to centralized systems, decentralized/onsite systems still involve local wastewater collection and treatment. They are considered to be much smaller with fewer people connected (single, several or tens or hundreds of households) and less costly, especially when greywater components have been separated from the blackwater for reuse. If the systems are properly situated, designed, operated and managed, they can provide substantial environmental and social benefits (e.g. reduction of freshwater consumption and wastewater generation) as well. The concentrated blackwater can be treated using several treatments (e.g. septic tanks, cesspools, soil drain fields, chemicals, bio-digesters, composting toilets and blackwater recycling systems). Decentralized/ onsite water reuse systems can also be integrated into the broader centralized systems in terms of clustered or contracting schemes for decentralized technology with centralized operation.
The design of a decentralized/onsite water reuse system requires a thorough understanding taking into account of scale, system components, end use requirements and other issues. This guideline can be useful for the application of design principles as well as feasible and cost-effective approaches for safe and reliable fit-for-purpose water reuse.