CSIRO Land and Water, Locked Bag 2, Glen Osmond, South Australia 5061, Australia.
Sci Total Environ. 2022 Feb 10;807(Pt 2):151676. doi: 10.1016/j.scitotenv.2021.151676. Epub 2021 Nov 16.
Three per cent of Australian agricultural irrigation comes from recycled water. The 1990s establishment of states' Environment Protection Authorities and their regulatory standards and effluent disposal charges led to effluents from Wastewater Treatment Plants (WWTPs) being used for agricultural irrigation. Adelaide and Melbourne, with agricultural land close to plants, expanded intensive vegetable industries. Sydney has limited land available and discharges 90% of its sewage through deep ocean outfalls after primary treatment. Brisbane with more distant farms, found pumping effluent hard to justify economically. Some larger regional cities/towns purchased farms to manage discharges as commercial businesses. Others market recycled water to nearby growers. Uses depend on treatment standards. Water with secondary treatment and pathogen reduction is suitable for processed crops, grazed or cut pastures, sugar cane, cotton and wine grapes, and is widely used for amenity horticulture, but requires careful salinity management. Water with tertiary treatment meeting log reduction pathogen standards may be used on food crops eaten raw (e.g. lettuce). Commonwealth government subsidies during the millennium drought (2001-2009) supported WWTP upgrades and irrigation infrastructure expansion. However, seasonal water demand and unwillingness of growers to pay full cost recovery prices led to some recycled waters still being discharged to water bodies. Some schemes over-estimated likely irrigation demand. Currently, there is scope for further developing recycled water agricultural irrigation by submitting business cases for subsidies from the new National Water Grid Authority. But there is increasing interest in the potential use of recycled water for drinking water augmentation, for which Australia has had guidelines since 2008. Perth has capacity for 28 hm/yr recycled water to replenish its groundwater drinking sources while Brisbane has three plants totalling 84 hm/yr for indirect potable supply, but not yet operating. Recycled water for critical human needs could eventually out-compete agricultural irrigation.
3%的澳大利亚农业灌溉用水来自再生水。20 世纪 90 年代，各州环境保护局的成立及其监管标准和废水处理费的征收，导致污水处理厂（WWTP）的废水被用于农业灌溉。阿德莱德和墨尔本，由于其靠近工厂的农业用地，扩大了集约化蔬菜产业。悉尼可利用土地有限，经过一级处理后，90%的污水通过深海排污口排放。布里斯班的农场距离较远，发现从经济角度来看，泵送废水难以证明其合理性。一些较大的地区城市/城镇购买了农场，将废水排放作为商业业务来进行管理。其他地区则将再生水出售给附近的种植者。用途取决于处理标准。经过二级处理和病原体减少的水适用于加工作物、放牧或刈割牧场、甘蔗、棉花和酿酒葡萄，并且广泛用于美化园艺，但需要小心管理盐分。经过三级处理并符合对数减少病原体标准的水可用于生吃的食用作物（例如生菜）。千禧年干旱期间（2001-2009 年），联邦政府的补贴支持了 WWTP 的升级和灌溉基础设施的扩展。然而，季节性用水需求和种植者不愿意支付全额成本回收价格，导致一些再生水仍被排放到水体中。一些计划高估了可能的灌溉需求。目前，通过提交国家水网管理局补贴的商业案例，进一步开发再生水农业灌溉仍有空间。但是，人们对潜在的再生水用于饮用水补充的兴趣越来越大，澳大利亚自 2008 年以来就有了相关指南。珀斯有能力每年处理 28 公顷的再生水来补充其地下水饮用水源，而布里斯班有三个总处理能力为 84 公顷/年的工厂用于间接饮用水供应，但尚未投入使用。对于关键人类需求的再生水最终可能会与农业灌溉竞争。
