Water Journal : Water Journal September 2011
awa news at the peripheries of the wetted zone. Dikinya & Areola (2010) reported build-up of salts in the agricultural land due to long- term use of recycled water. After three years of irrigation with recycled water, the electrical conductivity in soil increased from 105 to 235 μs/cm (about a 123% increases), cation exchange capacity of soil decreased from 9.21 to 8.61 cmol/kg and Na+ increased from 2.95 to 5.75 meq/100g of soil. Also, recycled water use has an impact on saturated hydraulic conductivity of soil. In one study, after two years of irrigation using recycled water, the hydraulic conductivity was reported to have decreased from 48 to 30.73 mm/hr (Gonçalves et al., 2007). These studies clearly indicate that for long-term viability of using recycled water for irrigation, it is necessary to control the salt in the recycled water. Moreover, it may be more efficient to control the salt at the source; ie, the point of generation of wastewater. Source Control Measures Effective source control measures are crucial for the control of salinity in recycled water. The success of any control measure demands the active participation as well as willingness of the stakeholders. Some source control measures for domestic household are (GMF 2011, Fresno City Council 2011): Education and awareness through: • Council or dedicated website • Flyers with utility bill • Posters, newsletter, media • School visits • Community and environmental groups Conservation • Reduced use of cleaning chemicals Change of practice • Choose liquid laundry detergents, or concentrated powder • With dishwasher and laundry detergents use half the recommended dose recommended, as the town water supply is typically soft • Minimise the use of salt and other food additives in cooking • Avoid using domestic salt-based water softener • Use organic compost rather than chemical fertiliser for home nursery Implementation of the 3Rs • Replace (products with an environmental friendly substance) • Reduce (the use of products contributing salinity) • Recycle (the household leftovers) By-laws • Segregate and separately manage wastewater that potentially consists of higher levels of salt. • Prohibition may be considered for certain products not to be discharged in the sewer. • Monitoring should be carried out daily, weekly, fortnightly or monthly to check the compliance at the source. Implementation of the above control measures at the source will no doubt be the most economical way of minimising the salt concentrations in the recycled water, thereby increasing the more widespread applications of recycled water. Therefore, the efficient use of a resource starts at the beginning of the cycle. For more information about the Source Management Specialist Network, please visit: www.awa.asn.au/LTW.aspx or email: firstname.lastname@example.org References Adrover M, Farrús E, Moy G & Vadell J, 2010: Chemical properties and biological activity in soils of Mallorca following twenty years of treated wastewater irrigation. Journal of Environmental Management, http://www. sciencedirect.com/science/article/pii/S0301479710002653. Aiello R, Cirelli GL & Consoli S, 2007: Effects of reclaimed wastewater irrigation on soil and tomato fruits: A case study in Sicily (Italy). Agricultural Water Management, 93, pp 65--72. SEARCH NO LONGER! Visit www.h2oz.org.au Managed by SEARCHING FOR THE BES CANDIDATES FOR YOUR COMP CHING FOR THE LATEST JOB UNITIES IN THE WATER SECTOR? There are surprising opportunities when you work in water Treated wastewater is frequently used for agricultural irrigation.
Water Journal November 2011
Water Journal August 2011