Septic Systems In Clay Soils: Introduction
Septic systems are designed to handle wastewater from toilets and sinks. They are often used in rural areas, where there is no other waste disposal system available. Septic systems can be installed on a site with clay soils, but they have to be carefully designed and installed because these soils do not drain well. Clay particles are very small and when exposed to water, they become sticky. The two main types of clay soils are as follows:
- Montmorillonite clay soil is a type of soil that is made up of montmorillonite, which is a hydrated magnesium silicate. It has a high water retention capacity. This means that it can hold water for a long time and release it slowly. The soil is often used in agriculture for irrigation purposes because the soil can keep the water from evaporating and make it available to plants for longer periods of time. When wet, montmorillonite clay soil is highly sticky and can expand as much as 150 times its original size reducing the spore spaces between the soil particles. This means that it cannot be used for a conventional septic system, since it has poor drainage and will not permit effluent to percolate through. Another major drawback of montmorillonite clay is the fact that it contracts when dry. The expanding and contracting montmorillonite clay exerts a lot of strain on your concrete septic system, which causes it to crack and crumble. Plastic septic systems are prone to buckling or caving in when put under this constant pressure.
- Kaolinite clay soil, with a chemical formula of Al2Si2O5(OH)4, has a low shrink-swell ability and is ideal for conventional septic systems.
Carry out a soil analysis test before installing a septic system to help in identifying the pH level and type of soil.
What type of septic system is best for clay soil?
The septic system is a vital component of any home. It is designed to eliminate the waste water from your home, keeping the environment and groundwater clean and healthy. There are many different types of septic systems, but only a few are suitable in locations with Clay Soils:
- An aerobic septic system is the best option for locations with clay soils. An aerobic septic system is a type of septic system that utilizes oxygen to digest sewage. This type of septic system is very efficient and releases a cleaner effluent.
- A mound septic system is a type of sewage treatment system that uses a mound of soil or raised drain field to filter effluent before it seeps into the ground. The mound is created by excavating and hauling dirt from other areas on the property to create a raised area, usually in the backyard. The soil is then layered with gravel and sand. A mound septic system may be more expensive than a traditional septic system, but it has several advantages over it. One advantage is that it can be installed in areas where there are no soils suitable for traditional systems, such as on clay soils, rocky or sloped terrain or near water sources like rivers and lakes. Another advantage is that its design allows for better absorption of effluent into the surrounding soil than conventional systems do, which can reduce groundwater contamination and odor problems caused by spills at the base of conventional systems.
- A cesspool is also a good option for an area with clay soils.
Septic System In Clay Soil
Installing a septic system in clay soil can present some challenges, as clay soils tend to have poor percolation rates and can be prone to compaction. However, with proper design and installation, a septic system can be effective in treating and disposing of wastewater in clay soil.
One option for a septic system in clay soil is to use a 1000 gallon septic tank as an effluent dosing chamber. These tanks can be used to store and release the effluent at a controlled rate, helping to prevent overloading and failure of the drain field. The size and capacity of the septic tank will depend on the size and wastewater production of the household or property.
In addition to using a dosing chamber, there are other measures that can be taken to improve the performance of a septic system in clay soil. These can include using a larger or multiple drain field areas to increase the amount of soil available for wastewater treatment, or incorporating aerobic treatment units to enhance the biological treatment of the wastewater.
It is important to consult with a professional septic system installer or engineer to determine the appropriate size and design of the septic system for your specific needs and soil conditions. They can help to ensure that your system is properly sized and configured to effectively treat and dispose of your wastewater in clay soil.
How to build a leach field in clay?
Building a leach field, also known as a drain field, in Kaolinite clay soil with a chemical formula of Al2Si2O5(OH)4, which has a low shrink-swell ability, requires careful planning and execution. The key challenge when dealing with clay soils is their poor drainage capabilities, which can lead to wastewater buildup and potential septic system failure. However, with the right techniques, a successful leach field can be constructed.
One option is to build a large leach field. This involves excavating a substantial area of the clay soil to create a network of trenches. These trenches are then filled with gravel or specially designed leach field pipes. The gravel provides a pathway for the effluent to percolate through the soil, while the pipes evenly distribute the wastewater. It’s important to ensure the trenches are spaced appropriately and follow local regulations regarding sizing and separation distances from structures and water sources. A leach field can be built in clay soil, but it has to be large. A larger leach field has a larger surface area for the effluent to seep through or evaporate. It makes up for the clay’s poor drainage.
Another approach is to construct a septic mound system, which is essentially a raised drain field. In this method, a mound of suitable fill material, such as sand, is built above the clay soil. The septic tank effluent is pumped up to the mound and then allowed to percolate downward through the fill material. The increased elevation aids in better drainage and prevents waterlogging in the clay soil below.
It is crucial to avoid building a leach field in Montmorillonite clay soil, as it retains water and has a significant shrink-swell ability. When this type of clay becomes wet, it can expand up to 150 times its dry volume, leading to soil compaction, cracks, and potential damage to the leach field.
When constructing a leach field in Kaolinite clay, it’s essential to carry out a percolation test to assess the soil’s ability to absorb water. This test helps determine the appropriate size of the leach field and ensures the system will function effectively.
To summarize, building a leach field in Kaolinite clay soil requires either a large leach field with trenches and gravel or a septic mound system. Careful consideration of the soil type, drainage capacity, and adherence to local regulations will contribute to the successful installation and operation of the leach field system, providing efficient wastewater treatment for the property.
Septic Systems In Clay Soils: FAQs
This sections will answer some of the most common questions that people have about septic systems in clay soils:
Septic Systems In Clay Soils: Final Thoughts
Septic systems are a great way to dispose of wastewater. They are the most common form of on-site sewage disposal in rural areas and small towns. Most conventional or traditional septic systems cannot be installed in clay soils since it has poor drainage. We recommend that you install an aerobic septic system with a raised mound for use in a location with clay soils.