Building Septic Tank

5 tips for building and installing a septic tank

5 Tips for Building and Installing a Septic Tank

A septic tank of sewage treatment plant is installed for any house or development where there is no access to a public sewer. Septic tanks or off mains drainage solutions are a very effective method of dealing with the sewage and wastewater generated from developments without a main sewer connection. As the septic system is a critical part of your infrastructure, it is essential that you build your septic system correctly to ensure trouble free long-term operation. Below are 5 tips you should take into consideration when building & installing a Septic tank.

1 – Septic system design

With any project, it is always important to have a basic design to work from. This means that when you start work onsite you have a clear plan of action. A septic system comprises two main elements. The tank and the percolation area or discharge area.

The septic system is generally designed based on the number of people in the house.  For detailed information on septic tank sizing please feel free to check code of practice.

Treated effluent that leaves the septic tank must then be discharged to a percolation area. This is the preferred disposal method for the majority of septic systems. A soakaway or percolation area is a gravel based infiltration area where the treated effluent from the septic tank is dispersed and soaks into the soil. The design of a soakaway is dependent on the soil conditions onsite. For wet ground a soakaway can be large, whereas for very permeable ground with a higher infiltration rate the percolation area can be smaller in size. Detailed guidance on the design of your soakaway based on a quick test of your soil onsite can be found here.

installing a septic tank

In certain areas, it may be permissible to skip the need to install a soakaway or a percolation area and to have a direct discharge of the treated effluent to a drain or a stream. However, in this instance it is then generally necessary to install a sewage treatment plant, as a sewage treatment plant achieves a much higher standard of treatment than a septic tank. The big advantage to installing a sewage treatment plant and having a discharge to a stream is that you require less space for a percolation area.

Once you know whether you need to install a sewage treatment plant or a septic tank, and whether to install a percolation area of a direct discharge then you are ready to start onsite.

2 – Choosing the right septic tank or sewage treatment plant

Choosing the right septic tank or sewage treatment plant is a crucial step in the process. At this stage, you will already have decided whether you will be installing a soakaway or percolation area, or having a direct discharge.

If you are having a soakaway or percolation area then it may be an option to install a septic tank. Septic tanks are generally manufactured from concrete or plastic. Concrete tanks are very strong, but to install one you need access for a truck mounted crane. Also, the lids are generally put on the tank after installation so this can lead to septic tank problems from leaks at poorly sealed joints. Most septic tanks installed these days are manufactured from reinforced plastic and are as strong as the concrete tanks. They are also single piece so there is no risk of leaks. If you are purchasing a certified septic tank you will need to ensure that it is to SR66 and EN12566-1 standards.

If you are having a direct discharge to a stream, then you may need to install a packaged sewage treatment plant.  Modern technologies mean that there are now some very low cost sewage treatment plants available on the market. If you are installing a sewage treatment plant you will need to make sure it is certified to SR66 and EN12566-3 standards. For further advice on septic tank costs please check our other blog post.

3 – Installation

When installing your septic tank or wastewater treatment system, there are two options. The first option is to complete the installation works yourself. Many people choose the DIY septic tank installation route. There are cost savings when choosing this option, but it is important that all drainage works completed meet the building regulations. If you are any way unsure about doing a septic tank upgrade or new system installation yourself, then you should hire a professional.

sewage treatment plant

Option 2 involves getting a professional septic tank installation company to complete the works for you. If you are doing this then it is always advisable to get two or three prices to make sure you are getting excellent value. If you are using a professional septic tank installer, then you should make sure they have experience installing sewage treatment plants, that they are fully insured and have references.

4 – Ventilation

Good ventilation is often something that is overlooked when installing a septic tank or sewage treatment plant. Bad ventilation can lead to odour issues onsite. It is very important that the ends of percolation trenches are vented, and that there is either a vent on the wastewater treatment plant or that there is a soil vent stack at the house. For further information on venting and preventing septic tank odours please check here.

5 – Maintenance and operation access

When installing your sewage treatment plant, consideration should be given to future maintenance. Any lids on the tank should not be covered over with soil. Access will be needed in the future for septic tank emptying and for inspection and checks that the system is running properly.  The tank should be within 30m of a driveway, as septic tank emptying companies generally only have 30m long hoses for emptying tanks. If a tank is over 30m from a driveway your septic tank emptying costs may increase.

Your sewage system is a very important part of your house. It is always recommended that you take out a maintenance contract with the supplier of your sewage treatment plant or septic tank.

septic tank emptying

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