Everything you need to know about reclaimed water.
Reclaimed water, used in place of fresh water where appropriate, is a valuable resource. Similar to stormwater recycling, reclaimed water is supplied as a fit for purpose resource for the irrigation of farm land and green spaces to reduce the reliance of potable water. Typically, it has a higher nutrient concentration level than other water sources providing an added benefit to the growth of crops and pastures. Using reclaimed water is a sustainable water source allowing for other water sources (raw and groundwater) to be used for other environmental and community benefits.
Yes and no. Reclaimed water is still a product of the treatment of sewage and certain controls are required to ensure there are no adverse effects on public health and land management. Livestock and irrigation controls for areas where reclaimed water irrigation occurs are important measures to ensure there are no adverse effects. In addition, the capacity of plants to take up nutrients and other dissolved substances is limited, so irrigation with reclaimed water may need to be monitored and managed to prevent buildup of contaminants in the soils.
This depends on system capabilities and the climate of your area. The amount of irrigation is governed by rainfall and evaporation, which together determine the water supply and demand of a pasture or crop. In most of Victoria, evaporation generally exceeds rainfall during the warmer months and reclaimed water is available for use. In the cooler months there is usually enough rainfall to meet the water requirements of growing plants. The majority of North East Water systems are operated during the warmer months.
Irrigation with reclaimed water can raise the salt levels around the roots of irrigated plants and needs to be managed to ensure that no adverse effects to the soil, groundwater or plant growth occurs. The keys to ensuring no problems occur are good drainage and no salt build-up prior to commencing irrigation. North East Water manage salinity through water, salt and nutrient balances and soil monitoring to manage any adverse effects.
With careful management, suitable crops and an appropriate irrigation site it is possible for a reclaimed water irrigation system to be sustainable in the long-term. The following factors are relevant to ensuring sustainable irrigation practices are undertaken:
Well managed and sustainable irrigation practices ensure that groundwater is not affected by the irrigation of reclaimed water. All reclaimed water schemes are managed in accordance with the Environment Protection Agency (EPA Victoria) guidelines which ensure risks to land, groundwater and surface waters are controlled.
The EPA publication "Guidelines for Environmental Management: Use of Reclaimed Water (pub. 464.2)" defines the arrangements required for containment on-site. Run-off collection systems are sometimes required to collect run-off and recycle it back onto the irrigation area. This prevents any run-off flowing onto neighbouring properties or to waterways.
Odour problems are usually the result of either poorly managed treatment and collection systems or overload of these systems. Properly managed irrigation systems of reclaimed water should not produce any odour.
Trace elements are essential for life. It is therefore not surprising that domestic wastewater usually contains small quantities, but these should not pose a threat to the soil quality. The balance of elements and nutrients does need to be monitored as normally occurs in irrigated agriculture.
Long-term application of nutrient-rich water can result in excessive accumulation, especially of phosphorus, in the soil. This can be dealt with in several practical ways: ensuring the input of nutrients always matches the output; ensuring the reclaimed water is diluted with fresh water during low-growth periods; and ensuring plant matter is removed.
One of the prime objectives of using reclaimed water for irrigation is to divert the discharge from the rivers and streams onto the land. This diversion assists in reducing the levels of nutrients in these streams that can otherwise lead to the growth of blue-green algae.
Reclaimed water from sewage treatment facilities is required to meet prescribed microbiological health standards. The treatment of reclaimed water is a very effective method of safeguarding public health. Factors influencing the survival of pathogenic microorganisms in soils include moisture, temperature, pH, nutrients, organic matter and the presence of some organisms and toxins. Micro-organisms remaining on exposed surfaces are destroyed by sunlight and desiccation. For this reason there is a withholding period after irrigation before access is allowed to public recreation areas.
No. The regulations and safety measures applied in Australia have been effective on preventing disease outbreaks caused by reclaimed water use.
Call our environment team on 1300 361 622 for further information.
Information on reclaimed water
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