More than 2 billion litres a year of nutrient-rich, treated effluent water will be diverted to crops instead of rivers and the ocean after a $120 million irrigation project secured final approval in south-east Queensland. After 10 years of planning, two years of construction, and rigorous testing by Queensland's Department of Health, the Wamuran Irrigation Scheme has begun providing recycled water to pineapple, berry and turf crops. The Unitywater project aims to benefit farmers, ratepayers, rivers, the ocean and the economy. Owned by the Moreton Bay, Sunshine Coast and Noosa councils, the statutory authority supplies drinking water and maintains 17 sewage treatment plants. This is the first time it has used recycled water to help farmers produce food. A 22-kilometre-long pipeline was constructed to transport Class A treated wastewater from the South Caboolture sewage treatment plant. It is pumped to the Moodlu quarry storage facility, then onto farmland north-west of Brisbane. The irrigation scheme will divert more than 2.6 gigalitres (2.6 billion litres) of recycled water annually. Previously, it was discharged into the Caboolture River, flowing into Pumicestone Passage and Moreton Bay, a nutrient-sensitive environment under increasing pressure from urbanisation. Unitywater chief executive Anna Jackson said she didn't want people to get the wrong idea of what was being discharged, "which is clear, highly treated water". But she said it would divert a nutrient load of 11,000 tonnes of nitrogen and nearly 2,000 tonnes of phosphorous annually to be used as nutrient-rich irrigation water on farmland. "The alternative for us was to build a longer pipe that would have led to an ocean outfall for longer-term population growth," Ms Jackson said. In Australia, wastewater is usually discharged to waterways or oceans via pipelines. The fast-growing region in the state's south east is expected to double its population from 520,000 to 1 million by 2040. Every extra flushed toilet and tap turned in kitchens and bathrooms puts pressure on sewage infrastructure. In a recent visit to Singapore, Moreton Bay City Mayor Peter Flannery was impressed by how it reused what is described as "new water." He said horticulture played a significant role in Moreton Bay's economy by producing crops, including strawberries, raspberries, pineapples, avocados and turf. Water a precious resource Just a small proportion of Australian agricultural irrigation comes from recycled water. But Queensland government climate modelling indicates droughts will increase in both frequency and duration by 2059. "It's a great use of something that's a natural asset that we usually get rid of," Councillor Flannery said. For Pinata Farms general manager Gavin Scurr, it provides security to produce pineapples and berries, whatever the weather. "We're in a wet period at the moment, but it will be dry again soon, and whenever it's dry, water is always a challenge," Mr Scurr said. "It limits our production, and it limits our ability to deliver consistent fruit to consumers. The third-generation grower said he had no concerns about the safety of using treated water that was not fit for drinking to irrigate crops for human consumption. He said Pinata Farms had been using a similar recycled water scheme to grow berries for 15 years in Stanthorpe. The Southern Downs Regional Council uses Class A recycled water to provide irrigation for horticulture, sports and recreation grounds, the golf course and school sports fields. "The water doesn't come in contact with the berry crop at all. It's all put in underneath the plastic," Mr Scurr explained. "There's a plastic barrier there for weeds and other purposes that protects the fruit from any of this water, so it doesn't come into any contact." While pineapples would receive overhead irrigation in their developmental stage, Mr Scurr said they would not be watered within one month of harvest. Mr Scurr said his family would prioritise using the recycled water on crops, allowing farm dams to stay full and overflow into creeks and ecosystems. "Other growers downstream from us will now have more water coming down the creek than there would have in the past as well," he said. Twin View Turf was the first farm to use the Wamuran Irrigation Scheme on about 200 hectares. General manager Lawrence Stephenson said they had used nearly 200 megalitres of recycled water since the scheme was commissioned this year. Mr Stephenson said it was a "complete change in agricultural practices" from having to "ration" water. Five farms will be included in the initial stage of the scheme. The irrigation water is currently subsidised.