Above ground sprinkler irrigation of effluent from home sewage treatment plants is being used more often because it is cheap to construct and design requirements are minimal. There is the perception that there is a low risk of system design failure compared to subsurface irrigation as sprinkler holes are too big to become clogged with suspended solids and carry over.
Surface irrigation is only safe if effluent sterilization is effective and consistent.
Chlorine is the most commonly used disinfection method as it is cheap and readily available. When chlorine is used for the disinfection of wastewater the following environmental and health impacts can occur:
- Production of disinfection by-products such as trihalomethanes and dioxins
- Removal of the microorganisms that help treat wastewater
- Removal of the beneficial bacteria in the soil, causing clogging and concentrated run off
- Non removal of viruses, parasitic worms and cysts, and
- Adverse effects on terrestrial and aquatic plants and animals.
The efficiency of disinfection will depend on the characteristics of the wastewater including, suspended solids, colour, BOD, COD, pH, nitrogen and water hardness and the type of disinfection facility such as contact time, ratio of dose to flow and temperature. The complexity of managing a safe community and environmental health outcome is the reason that municipal treatment facilities require 24 hour a day 7 day a week monitoring to ensure all these levels are correct and safe before being discharged into the environment.
The expectation that a home sewage treatment plant (a mini version of a Council plant) serviced just 4 times per year with no monitoring of the sewage inflows and strengths, could safely treat effluent to a quality safe enough to spray around a family’s back yard is unrealistic and instils a false sense of security.
Sprinklers like these used to spray effluent above ground, increase the risk of human contact and the risk to neighbours due to wind drift, especially if chlorine tablets have run out and no sterilisation has occurred.
The inability to accurately control sterilization using chlorine tablets is a major issue recognized worldwide by the wastewater industry and responsible authorities. Until a solution is found to ensure adequate and safe sterilization using the industry standard, chlorine tablets, we believe all wastewater should be disposed where kids can’t play, underground in trenches!
Advanced Enviro-Septic is an innovative passive sewage treatment system that maximizes natural processes to purify wastewater to advanced secondary quality without the need for power, pumps, aerators or harmful chemicals. AES is a cost-effective and environmentally friendly wastewater solution that is scalable to suit any domestic or commercial application. AES has been installed in over 400,000 homes, schools, hospitals, caravan parks, national parks, RV stops, resorts and towns around the world since 1995. AES is a trusted product certified worldwide.