Faq's

Septic tanks are designed to treat and manage wastewater from homes and businesses that aren't connected to a main sewage system. Septic Tanks have three compartments. Here's how they work together:

• 1. Separation of Solids: Wastewater enters the first chamber of the septic tank, where solids settle at the bottom. Heavier materials form ‘sludge’, while a small amount of anaerobic breakdown starts to occur. This process helps separate solid waste from liquid without the presence of oxygen.
• 2. Scum Layer & Liquid Flow: The liquid then flows into the second chamber, passing through a baffle that keeps solids behind. A ‘scum layer forms on top, trapping odours and preventing them from escaping. A specially designed dip outlet pipe ensures that only the liquid passes through to the next stage, preventing blockages caused by scum.
• 3. Percolation: In the final stage, the liquid flows into a percolation area, where it undergoes further treatment by filtering through the soil. This process helps remove harmful bacteria and nutrients before the wastewater re-enters the groundwater. By efficiently managing solids, liquids, and percolation, septic tanks provide an effective and eco-friendly solution for wastewater treatment in off-main systems.

The key difference between a septic tank and a sewage treatment plant lies in how they process and treat wastewater:

• 1. Septic Tank: a basic system that primarily separates solids from liquids in the wastewater. It uses natural biological processes to break down the waste in an anaerobic environment (without oxygen). The liquid effluent then flows to a soakaway or percolation area where it is absorbed into the soil. While it reduces solids, the wastewater discharged is not fully treated, so it still has contaminants.
• 2. Sewage Treatment Plant: also called a wastewater treatment plant, this provides a more advanced treatment process. It not only separates solids from liquids but also introduces aerobic treatment (using oxygen) to further break down and treat the wastewater. This results in a much cleaner effluent that can be safely discharged into watercourses like rivers or streams, making it more environmentally friendly.

In summary, septic tanks offer basic wastewater separation, while sewage treatment plants provide a higher level of treatment that is more suitable for environmentally sensitive areas, larger populations and stricter discharge requirements.

Biochemical Oxygen Demand (BOD) is a key metric used to evaluate the amount of oxygen that microorganisms consume while breaking down organic matter in wastewater. It helps gauge water quality and the effectiveness of wastewater treatment processes.  BOD is essential for understanding water pollution levels. High BOD values indicate a large amount of organic waste, which can deplete oxygen levels in water bodies, potentially harming or killing aquatic life due to low oxygen availability.  Wastewater treatment plants use BOD testing to monitor waste loads and ensure compliance with environmental regulations. It's also crucial in determining the efficiency of treatment processes and the impact of effluent on natural water bodies.

In wastewater treatment, sludge refers to the solid, semi-solid, or slurry materials that are left behind after wastewater has been treated. It is primarily made up of organic and inorganic materials, microorganisms, and water, and is a byproduct of both primary and secondary treatment processes. Proper sludge management is crucial for minimising environmental impact and reducing waste.