Using a shallow, high-rate pond system to treat wastewater will slash the loss to evaporation as well as boosting the rates of removal of bacterial and viral pathogens, research has found.
At the moment, evaporation from treatment ponds wipes out a large proportion – up to 90% – of reclaimed water in South Australia’s small rural communities, where there is strong unmet demand for clean and relatively cheap water.
In conventional waste stabilisation ponds the combined decontaminating effect of sunlight and algal activity is limited to an upper layer of about eight to 20 centimetres.
The high rate algal pond exposes viral and bacterial pathogens to the direct effect of ultra-violet light while also inducing stronger algal growth.
“The chemical effect of the algae is to increase levels of alkalinity in the water, which acts as a strong disinfectant,” researchers said