If you have condominial sewerage (or any sewerage, for that matter) you have the opportunity to practise wastewater-fed agriculture – using treated wastewater to raise fish and/or (but preferably ‘and’) irrigate crops. In urban areas this is termed ‘wastewater-fed urban agriculture’. IDRC Canada has published many reports and books on urban agriculture (UA) in general and wastewater-fed UA in particular – for example, Wastewater Use in Irrigated Agriculture: Confronting the Livelihood and Environmental Realities (2004) and, just out this month, Wastewater Irrigation and Health: Assessing and Mitigating Risk in Low-income Countries (though the hyperlinks to the chapters are not yet in – in the meantime there’s the pdf of the whole book here; hard copies can be purchased from Earthscan). See also Urban Agriculture and, more generally, Wastewater Use in Agriculture and Wastewater Use in Aquaculture.
The World Health Organization has published Guidelines for the Safe Use of Wastewater, Excreta and Greywater in agriculture and aquaculture (3rd edition, 2006).
Remember: “Wastewater is too valuable to waste”.