ABSTRACT
Recycling of greywater is often performed in decentralized systems and is distinct from the prevailing paradigm in most western countries where treatment is centralized. Speci—cally in Israel, the centralization of all water-related systems and wastewater treatment is almost complete. As noted in the previous chapter, the safe use of greywater is important because if unaddressed, the presence of pollutants can pose health and environmental hazards. However, greywater treatment risk from a decentralized system is not the same as in centralized treatment of full domestic wastewater. First, there are constraints related to the construction of decentralized systems including space, cost, maintenance, and monitoring. Also, unlike in a centralized treatment structure, the volume and quality of water šowing into systems serving a single family (or a small number of families) will likely experience signi—cant variations. For example, when there are guests, the amount of water used will be proportionately greater than usual, while there may be dry periods when the residents are away on vacation. Fluctuations in water quality may also result from a one-time intensive use of soap, acid, or hypochloride solution (such as during holiday time) and from the entry of small amounts of urine and feces, paint, solvents, and more. Hence, the characteristics of greywater present challenges that require targeted solutions different from those of domestic wastewater treatment by central systems.
