There is a vast array of wastewater treatment systems by various manufacturers throughout Australia, making you feel overwhelmed when buying a wastewater system.
Each brand and system type are all varied to a degree, but all have the same desired outcome of treating your wastewater and returning it to the natural environment safely.
This particular article will look at the differences between Primary Wastewater and Secondary Wastewater Treatment Systems.
Primary Wastewater Treatment Systems
A “primary” system is essentially a traditional septic tank and absorption trench with no additional systems. The effluent and wastewater flows from the premises into the Septic Tank for treatment and then to the absorption trenches using gravity (a pump is used when gravity is unachievable).
Septic tanks turn wastewater into an effluent that must be disinfected via UV exposure, sand filters, wetlands, or leached back into the ground via irrigation or sprinklers.
The absorption trenches are underground, so the effluent doesn’t come into contact with humans and animals because the quality of the effluent is generally poor. Turf or other suitable plants are planted on top of the trenches to absorb nutrients and remove excess water through evapotranspiration.
Note, Septic tanks do not kill pathogenic bacteria, viruses or parasites.
You should take extreme caution with effluent coming into contact with people, food, clothing and pets.
Septic tanks (Primary Waste Treatment Systems), absorption trenches, or leach field style systems are Australia’s most common septic systems. Primary Waste Treatment Systems tend to be a cost-effective option with low installation and ongoing maintenance costs.
Advanced Secondary Treatment Systems
Advanced Secondary Treatment Systems (STS) and Aerated Wastewater Treatment Systems (AWTS) treat the wastewater from your home to a much higher quality than a Primary system.
For example, our Advanced Secondary Treatment Systems receives all wastewater from the premises, including the kitchen, toilet, shower and laundry, and quietly and efficiently recycles all the household wastewater into clean, clear and odourless water suitable for irrigation on your garden and lawns.
How Does Advanced STS Work?
The influent enters the Primary chamber, where scum and solids are separated from the raw influent. Primary treated effluent flows through to the aeration tank. The Primary tank will also be a storage chamber for sludge returned via the Clarification Chamber.
Once the effluent enters the Secondary chamber, air is introduced via an air blower to create an environment for aerobic bacteria and other helpful organisms to consume the organic matter present. The aeration tank (Secondary treatment tank) is designed to help prevent short-circuiting of the wastewater to ensure extended aeration. Media is also present in the tank to support the growth of bacteria.
The Clarification chamber is essentially a quiescent zone where suspended particles/solids are settled out of the water. These particles are returned to either the primary or secondary chambers via a sludge return which aids in further biological reduction, de-nitrification and providing a constant food supply rich in microbes supporting the system through periods of limited flows.
And lastly, disinfection is achieved via low doses of chlorine to kill off any remaining harmful organisms, which is performed through an automatic chlorinator.
For these reasons, Advanced STS and AWTS are fast becoming the most popular choice for residential septic systems and commercial wastewater systems used throughout Australia. Garden Master septic systems are Advanced STS and the systems we recommend.
If you’re unsure what septic system would suit your property, check out our article Septic Tank Buying Guide or simply get in touch for some friendly advice.
