Common Types of Materials for Septic Tanks

Septic tanks are buried in water-tight chambers that collect domestic wastewater, treat it, and release it to a soak pit before releasing it into the environment. Septic tanks can be made from concrete, plastic, FRP, or masonry. 

Steel Portable Septic Tanks
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This article explains the various types of septic tanks based on the material and their features and applications. 

1. Concrete Septic Tanks

Concrete septic tanks are one of the strongest and most conventional types used for decades. They were initially constructed cast in situ using reinforced cement concrete. But now, prefabricated concrete septic tanks are available and can be installed on-site. 

Fig.2. Concrete Precast Septic Tanks

In situations where we require customized and high-capacity septic tanks, which are not available in prefabricated options, concrete septic tanks are designed specifically and constructed on-site.

Features Concrete Septic Tanks

• R.C.C Septic tanks have high strength and durability due to the use of reinforced concrete. They enhance structural integrity by resisting external pressures, environmental conditions, and potential ground movements. 
• Compared to conventional brick masonry septic tanks, R.C.C. septic tanks have a high initial cost and complex construction process. But this demerit can be compromised by considering the lower maintenance charge, and high strength & durability it offers. R.C.C. septic tanks have a longer life span exceeding 30 years. 
• R.C.C. septic tanks require less maintenance compared to brick tanks. The solid and impermeable nature of the R.C.C. surface prevents leaks and the risks of root infiltration and groundwater contamination. 
• R.C.C. is best employed in construction sites with high groundwater table levels or unstable soil conditions. 
• The robust characteristics of R.C.C. septic tanks help prevent the release of contaminants from the tanks to the surrounding soil. This helps to achieve better environmental protection.  

2. Masonry Septic Tanks

Septic tanks are typically made from masonry bricks as they are way cheaper and easier to construct compared to other types of septic tanks. Brick septic tanks require less specialized labor but this should no case affect the quality of construction. The quality of the bricks and the mortar used for the construction of septic tanks influence future leaks and structural issues. 

Fig.3. Brick Septic Tanks

Given the enormous number of joints in the masonry walls of a septic tank, regular maintenance is required to keep the structure's integrity stable. 

Even though brick septic tanks perform less compared to concrete septic tanks, the former can be used for smaller and less demanding installations where budget constraints are a primary concern. 

3. Plastic Septic Tanks

Plastic septic tanks are the second most popular type after concrete septic tanks. They are known for their lightweight structure, ease of installation, corrosion-free, and affordable features. Unlike concrete or brick septic tanks, mortar or concrete is not used for any future leak or permeability issues. 

Fig.4. PVC Septic Tank

In addition to these features, plastic septic tanks are buried at a shallow depth often limited to 4 feet below the ground surface. This depth won't give protection to tanks in areas with high-freezing temperatures or heavy vehicle traffic. 

Plastic septic tanks require regular maintenance, as it is prone to wearing out. Their fixing cost is less, but their maintenance thereafter would cost more closer to concrete septic tanks. 

4. FRP Septic Tanks

Fiber-reinforced plastic (FRP) septic tanks are composed of synthetic resin and fiber-reinforced plastic. They are known for their lightweight, fire surface finish, hardness, high strength, and corrosion resistance. Due to ease of installation and varied capacity options, FRP is used in industrial, residential, and commercial areas. 

5. Steel Septic Tanks

Steel septic tanks have traditionally been less common in wastewater management due to concerns about their longevity and cost compared to concrete or fiberglass options. However, advancements in steel technology and construction techniques have significantly improved their performance and durability.

While steel septic tanks were once considered less durable due to corrosion concerns, modern steel alloys and protective coatings have greatly enhanced their resistance to rust and degradation. This has extended their lifespan, making them a more viable option for many applications.

Additionally, steel septic tanks can offer advantages in terms of:

• Lightweight: Steel tanks are generally lighter than concrete tanks, making them easier to transport and install.
• Customizability: Steel tanks can be customized to meet specific site conditions and requirements.
• Efficiency: Some steel tank designs incorporate features that improve wastewater treatment efficiency.

While steel septic tanks are still less common than concrete or fiberglass tanks in many areas, their performance and durability have improved significantly. As technology continues to advance, steel septic tanks may become a more popular choice for wastewater treatment applications.

Portable steel septic tanks remain a valuable option for temporary or emergency wastewater storage and treatment needs, offering convenience and flexibility. They are particularly useful in situations where underground construction is challenging or impractical.

Conclusion

In conclusion, the choice of septic tank material depends on various factors, including construction costs, maintenance requirements, and specific site conditions. Concrete and plastic tanks remain popular due to their durability and affordability. However, advancements in steel technology have made steel tanks a more viable option, offering benefits like lightweight construction and customization.

When selecting a septic tank, it's essential to consider both initial construction costs and long-term maintenance expenses. Factors such as tank size, location, soil conditions, and water table should be carefully evaluated to ensure the chosen tank is suitable for your needs and budget.

By considering these factors and seeking expert advice, you can make an informed decision and select the best septic tank for your property.

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