Sewage Treatment Plants

We offer experienced, peace of mind installation for any domestic or commercial sewage treatment plant. Our engineers guide you through the process while sharing their wealth of experience to ensure all of your property’s requirements are carefully considered.

Sewage treatment plants are the regulation-approved method when dealing with off-mains sewage treatment. Many properties still use septic tanks and soakaways to discharge partially treated wastewater, which can be largely detrimental to the environment and fail regulation requirements. For peace of mind, it is always best to check the sewage system of your property, and we will happily advise on septic tanks, holding tanks, soakaways, and any other type of sewage system you have.

We believe in doing the best for our environment, which is why we work as efficiently as possible to improve Septic Tanks, Holding Tanks & Treatment Plants to meet the latest regulation standards as soon as possible.

*Typically 2-3 days for installation and FREE above-and-beyond finishing service.*

We use only the most reliable sewage treatment plants to replace septic tanks. These incredible systems come with a 25-year manufacturer guarantee (this does not affect your legal rights as a consumer). Our most commonly installed systems are the WPL Diamond, BioPure and Marsh Ensign sewage systems.

  • No mechanical parts
  • Cone-shaped systems are virtually maintenance free (BioPure & WPL Diamond)
  • Low wattage pumps mean running costs are as little as possible
  • Cone-design means solids don’t build up and because of this, needs emptying less frequently (Manufacturers recommend every 3-5 years)
Internal diagram of a BioPure sewage treatment plant system

We are strong believers in avoiding systems with regular maintenance requirements. The simpler the better. That’s why we recommend WPL Diamond, BioPure and Marsh treatment plants most of the time. However, we are more than happy to discuss installing a different system such as KlargesterTricelHarlequin or Vortex.

Drainage Fields

What is a drainage field?
A drainage field is a looped section of slotted pipes (also known as perforated pipe) in the ground, surrounded in, and laid upon a bed of gravel. The aim of a drainage field is to allow treated water (in the case of a treatment plant) to make it’s way through the gravel allowing bacteria to form on the gravel which allows for further filtration. This helps to remove contaminants from the water prior to it entering the ground surrounding the drainage field. Also, to give treated water (in the case of a treatment plant) a sufficient area to disperse evenly.

How large are drainage fields?
Drainage fields come in different sizes depending on the amount of usage it will see and what the ground type is. For example, if you have dense clay underground, your drainage field would be larger than someone who has a lot of sandstone even if you had the same usage. The best way to determine the size your drainage field should be is to calculate the amount of usage your system could have and then run percolation tests.

Percolation tests

What is a percolation test?
A percolation test determines the rate of water absorption into the ground. The test measures how long it takes water to drain away from a saturated hole dug into the ground; the result determines both the suitability and permeability of the soil, and ensures that the ground has sufficient drainage capacity to handle the amount of water that will come from the drainage field intended to be installed.

On paper, Percolation tests appear to be easy to test if you wish to have a drainage field for your sewage treatment plant. However, the test must be carried out with pinpoint accuracy to determine the porosity of your ground. Fortunately, at Sussex Water & Drainage, we have all the equipment and knowledge to ascertain Vp measurements accurately.

The percolation test involves excavating a 300mm square hole to a depth of 300mm below the proposed invert level of the discharge pipe. After carefully removing all loose debris, we will fill the void with water to the top of the 300mm mark and leave this to seep away overnight. We will then return and fill to the same point and closely observe its time from 75% capacity to 25% capacity. Using a calculation of how much water has dispersed in the given time with the depth lost, we can accurately read the average time in seconds (Vp) for the water to drop by 1mm.

Can I have a drainage field with my Septic Tank?
Septic tanks release untreated wastewater into the environment and often solids, tissue paper etc will find their way through the outlet pipe and can create blockages as well as being extremely harmful to wildlife. Whilst drainage fields are often used as secondary treatment, the quality of the liquid leaving septic tanks is so poor it’s likely to decrease the efficiency of a drainage field rapidly and will result in an outlet blockage. It is for this reason that we do not install drainage fields on the back of septic tanks. The best thing that you could do is replace your septic tank with a sewage treatment plant. This is because treatment plants release clean water back into the environment and the systems that we install at Sussex Water Drainage Ltd are maintenance free, cost pennies to run and require emptying 5 times less frequently than a traditional sewage system.

If you’d like to know what your options are regarding your sewage system, get in touch and we’ll guide you absolutely free of charge.