[Accessed: 27.10.2010]

This is the link to all four WHO guidelines on the safe use of wastewater, excreta and greywater for agriculture: Volume 1 discusses policy and regulatory aspects; Volume 2 presents guidelines for wastewater use in agriculture; Volume 3 highlights guidelines for wastewater and excreta re-use in aquaculture; Volume 4 contains the guidelines for excreta and greywater re-use in agriculture.