How Soil Impacts your Septic System

Septic systems provide low-cost sewer services to to remote households that are not part of public sewer systems. They rely on a series of biological functions and human intervention to work properly. One of the main players in septic action is soil. Soil works mainly in two ways to prepare wastewater for reentering the ground. Well-treated water is important for maintaining healthy ground and surface waters which are heavily depended upon for drinking. 

The Journey of Effluent

After you shut off the shower, sink, or flush the toilet, all that water continues to travel. If you rely on a septic system for your sewer treatment, this water first reaches the septic tank where it undergoes a process that separates heavy solids and lighter materials like oils and grease. The heavy solids sink to the bottom of the tank and form a sludge layer while the light materials float at the top forming a scum layer. The liquid wastewater, or effluent, continues to flow between these layers. The effluent’s immediate next stop is the distribution box where it then travels through several pipes to reach the drainfield.

Soil Beneath the Drain Field

The soil that sits below your drainfield is the final step in treating the effluent that passed through the septic system. The key role of soil is to play the part of a natural filter. Soil is composed of 50% solid materials and 50% pore space. The solid materials are from minerals and decayed plant and animal remains, or organic matter. Soil texture is crucial to determining how well the soil filters the incoming effluent. Sand, silt, and clay particles are all present in soil. It’s the ratio of these three particles that affect how well the soil is able to hold water and eventually allow it to enter the ground. Besides physically providing a surface for the wastewater to run over, soil contains trillions of microscopic organisms that feed on the organic matter found in the effluent.

Physical Water Treatment

When water passes through the soil in your drainfield, large particles are filtered out while others are absorbed into the soil or stick to it. Negatively charged soil particles attract and hold positively charged chemicals and viruses. Minerals in soil also bind with pollutants. Nutrients like nitrogen, phosphorus, and oxygen are also removed by the physical properties of soil.

Biological Water Treatment

Soil contains a variety of microbes that rely on the organic material in the wastewater for sustenance. Bacteria, algae, protozoa, fungi, rotifers, and nematodes are all present in a typical septic system. Aerobic bacteria are the most effective at breaking down materials in wastewater. This type of bacteria relies on oxygen to survive. Anaerobic bacteria is also found in your septic system in your septic tank. Anaerobic bacteria is responsible for the buildup of biomat as they are ineffective at clearing out the wastewater. For this reason, soil that is oversaturated with water is not a good filter, as it blocks oxygen allowing anaerobic bacteria to thrive.

To replenish your septic system’s supply of “good bacteria” it is important to use an all-natural monthly septic additive. Call 800-397-2384 for a free trial today!

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