Septic Systems In Clay Soils

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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:

  1. 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.
  2. 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.
  3. A cesspool is also a good option for an area with clay soils.
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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?

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.

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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:

The cost of a septic system in clay soils is higher than other soils because it needs more expensive equipment. A conventional septic system is installed in most soil types and it relies on gravity to move effluent from the tank to the drain field. On the other hand, clay soils use a mound septic system or an aerobic septic system.

An aerobic septic system utilizes an aerator pump to infuse oxygen into the system and also uses sump pumps to discharge waste water through the system. A mound septic system also uses pumps to move effluent to a raised or elevated mound. Aerobic septic systems and mound septic systems are expensive, but they are also more environmentally friendly than traditional septic systems. In general, aerobic or mound septic system will cost $10,000-$30,000.

Loam soil, which is a mixture of sand, silt, and clay, is the best soil for a septic system because it is excellent at vigorous filtering septic effluent while allowing it to percolate through.

Septic tanks should not be constructed in areas with clay soil due to its poor drainage properties. Clay soil has a high compaction level, inhibiting proper percolation and drainage of wastewater from the septic system. The impermeable nature of clay prevents efficient absorption of liquid, leading to potential backups, odors, and system failure. In such conditions, the septic tank’s effectiveness is compromised, posing environmental and health risks. Therefore, choosing well-draining soil types is crucial for the successful functioning of a septic system, ensuring proper filtration and minimizing the risk of contamination.

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Optimal soil for septic systems falls within a sweet spot, striking a balance between gravel and clay densities. The ideal soil possesses qualities of porosity and cohesion, allowing for effective water absorption and filtration without excessive compaction. This balance ensures that wastewater can percolate through the soil layers, facilitating the natural purification process crucial for a septic system’s functionality. This Goldilocks soil, neither overly dense nor too loose, guarantees a steady flow of treated water into the surrounding environment while preventing clogs and backups. Choosing such well-balanced soil becomes paramount, creating an environment where the septic system thrives, maintaining its efficiency and longevity for a healthier, more sustainable wastewater disposal solution.

Much like the earthy fragrance after a refreshing rain, the odor of clay soil is distinct and invigorating. It exudes a lush and fresh aroma reminiscent of the great outdoors. This characteristic scent arises from the unique composition of clay, releasing a natural, earthy fragrance that reflects the soil’s mineral-rich essence. The aroma is often associated with fertility and the vitality of the land. Walking on clay-rich soil or gardening in such environments provides a sensory experience akin to nature’s own perfume, connecting individuals to the fundamental and grounding elements of the earth.

In areas with challenging clay soil, an effective solution lies in the integration of an aerobic septic system featuring raised or elevated septic mounds or drain fields. This innovative design tackles the slow percolation and poor drainage issues associated with clay soil. By incorporating a substantial leach field or drain field, this specialized septic system compensates for the soil’s limitations, ensuring efficient wastewater treatment. The elevated components facilitate better aeration and drainage, optimizing the overall performance of the septic system. This tailored approach to clay soil complexities underscores a commitment to sustainable and adaptable solutions, providing a reliable and long-term wastewater management strategy for areas where traditional systems may fall short.

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.