Greywater reuse for different purposes in Sweden : A literature review

• Globally, water demands are increasing as a result of e.g., population growth and a warmer climate; at the same time freshwater supplies are becoming scarcer. Also in parts of Sweden where water shortage historically has not been a concern, the availability of freshwater for potable water use is declining, especially in the summer. As a result, alternative water management strategies are receiving increased attention in an effort to reduce the pressure on potable water sources. One strategy is the treatment, recirculation and re-use of greywater, a type of water that can be collected in source-separating wastewater systems. Hence, the aim of this literature review was to provide knowledge necessary to understand how greywater can be treated, recycled and re-used in the society, with an emphasis on reuse in Sweden. The review covers different aspects including greywater characteristics, greywater treatment processes, legal frameworks and guidelines on greywater re-use, global examples as well as summary of findings from sustainability analyses conducted on greywater re-use systems.Greywater makes up 75–90% of the total domestic wastewater volume and thereby represents an important source for water reuse in systems with source-separating wastewater systems. Data of the quantity of greywater produced in households globally and in Sweden vary. According to Swedish studies, one person may produce between 66 to 150 l/d. Additionally, research indicates that greywater contains less pathogens and nutrients compared to mix wastewater due to the separation of greywater from blackwater, which in turn contains the human excreta. However, the concentrations of measured parameters vary significantly between different areas. Therefore, in order to ensure the quality of greywater, site-specific measures are necessary.Studies have been conducted on different greywater treatment methods for non-potable re-use, with biological and filtration techniques receiving the most attention. However, it is challenging to make generalizations about the optimal treatment techniques based on the end-usage, due to the variation in greywater characteristics between sites. In addition, this review shows that there is a lack of legal guidance for greywater reuse, which makes it more challenging for practitioners to understand what levels of treatment that are required before the reclaimed water can be reused in used in society. The review also shows that further sustainability analyses should be conducted on greywater reuse systems, in order to understand their benefits more comprehensively.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Samhällsbyggnadsteknik -- Vattenteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Civil Engineering -- Water Engineering (hsv//eng)

Nyckelord

VA-teknik

Urban Water Engineering

Publikations- och innehållstyp

vet (ämneskategori)

rap (ämneskategori)