The Biological Septic Process

The Basics: Introducing the septic system

Before diving into the biology, let's break down the structure of a typical septic system. It consists of two main components: the septic tank installation and the drain field (also known as the leach field).

The septic tank is a watertight container, typically made of concrete, fiberglass, or polyethylene, and it is buried underground. It receives wastewater from your household, holding it long enough to allow solids to settle at the bottom (forming sludge) and oils and grease to float to the top (forming scum). The middle layer of partially treated water exits the tank into the drain field.

The drain field, or leach field, is a network of perforated pipes buried in trenches filled with gravel or sand. The wastewater is distributed through these pipes, allowing it to percolate into the soil, where further treatment occurs.

The biological magic inside the septic tank

The real magic happens inside the septic tank where microorganisms break down waste. Let’s take a closer look at the biological processes.

The septic tank primarily operates under anaerobic (without oxygen) conditions. This environment is perfect for anaerobic bacteria. These bacteria feast on organic matter from toilets, sinks, and showers, and they break down the waste into simpler compounds.

As the bacteria digest the organic matter, they produce methane and carbon dioxide as byproducts. While these gases escape through the venting system, the process itself is crucial for reducing solid waste in the tank.

Not all waste is broken down by bacteria. Heavier solids settle at the bottom, forming sludge, while lighter fats, oils, and grease float to the top, forming scum. This is why periodic septic tank pumping is mandatory!

The biological processes in the drain field

While anaerobic bacteria steal the spotlight, the aerobic (with oxygen) processes in the drain field are often overlooked. After the wastewater leaves the septic tank, it enters the drain field, where aerobic processes take over.

As the effluent percolates through the soil, it undergoes physical filtration, where remaining solids are trapped in the soil matrix. Aerobic bacteria continue breaking down any remaining organic matter in the effluent. Further, plants absorb nutrients like nitrogen and phosphorus from the effluent.

Maintaining your septic system

Biological processes are incredible and reliable, but they can’t do it all. Property owners must lend a helping hand. Maintenance, including septic tank cleaning and pumping, is key to maximizing the efficacy and lifespan of your septic system.

Whether you need routine septic service or an emergency septic tank repair, the septic professionals at Septic Blue are ready to help. Call or message us today to get in touch with a responsive member of our team.