Waste Water Services

Households that are not served by public sewers usually depend on wastewater treatment systems, either proprietary systems or septic tanks, to treat and dispose of wastewater. A well designed, installed, and maintained wastewater treatment system can provide years of reliable low-cost service.

When systems fail to operate effectively, property damage, ground and surface water pollution, and disease outbreaks can occur. Therefore, it makes good sense to understand and care for your wastewater treatment system.

What is a Wastewater Treatment System?
A wastewater treatment system is a piece of infrastructure into which the raw sewage from the house enters and is partially treated. The partially treated effluent is then discharged to a percolation area for final treatment and eventual disposal to ground.

Wastewater treatment systems come in various shapes and sizes and are normally located in your garden. Wastewater treatment systems accept all waste water from your house, which includes toilet, shower, sink, kitchen and washing machine wastewater. A percolation area typically consists of a system of sub-surface perforated pipes, which allows the liquid to drain into the surrounding soil.

How does a Wastewater Treatment System work?
A wastewater treatment works like a simple sewage treatment works and the partially treated effluent drains from the tank’s outlet pipe via a distribution box to the percolation area.

The wastewater is collected in the tank. Heavier solid material entering the tank will sink to the bottom. This is called sludge. The materials that remain near the top of the tank (oil, fat, and grease) are called scum.

Naturally occurring bacteria which are present in the sewage are encouraged to breed within the tank and digest the solids. Over time, partially decomposed solids build up on the bottom of the tank. This sludge has to be removed regularly to ensure that the system continues to work properly and to prevent the percolation area becoming blocked. After the partially treated wastewater leaves the tank it flows into the percolation area trenches. In the percolation area, holes at the bottom of each distribution pipe allow the wastewater to drain into gravel trenches for temporary storage.

The soil below the percolation area provides the final treatment and disposal of the wastewater treatment effluent. As the effluent passes into the soil, most of it percolates downwards and outwards. The soil then filters the effluent as it passes through the pore spaces.

How can I tell if my Wastewater Treatment System is developing problems?

  • Warning lights are flashing;
  • Sewage surfacing over percolation area;
  • Sewage back-ups in the house;
  • Slow draining toilets or drains;
  • Sewage odours;
  • Lush, green growth over the percolation area;

  • These problems tend to arise due to blocked pipes or excessive build up of solids in the tank. You may be able to clear pipe blockages by using drain rods but in some cases you may need to call a qualified plumber. The tank may also require emptying.

    How do I care for my Wastewater treatment System?

  • Keep records of when it was last cleaned and inspected by the manufacturer.
  • Do monthly inspections of the area around the tank. Prevention is always better than cure, as, once damage is caused to the drainage system, replacement is often the only option. In the long term it pays to be vigilant.

  • What are the DOs and DON'Ts for my Wastewater Treatment System?

  • DO: divert other sources of water, like roof drains away from the wastewater treatment system. Excessive water upsets the system.
  • DO: set up maintenance contracts with the suppliers of the system.
  • DO: desludge the tank as often as is necessary.
  • DO: act immediately if there is a sign of any blockage or any sign of pollution.

  • DON'Ts
  • DON’T: use bleaches and disinfectant, or use sparingly, as they could kill the bacteria that help to digest the waste.
  • DON’T: use your toilet as a rubbish bin, or poison your system by pouring harmful chemicals, cleansers, oil or grease down the drain.
  • DON’T: flush rags, disposable nappies, kitchen towels, wipes, sanitary items or cotton buds down the toilet.
  • DON’T: enter a wastewater treatment plant. Toxic gases are produced by the natural treatment processes and can kill in minutes.
  • DON’T: allow anyone to drive or park over any part of the system.
  • DON’T: plant anything over or near the percolation area except grass. Roots from nearby trees and shrubs may clog and damage the drain lines.
  • DON’T: wash paint brushes in the sink or put brush cleaning liquids into the drains leading to the wastewater treatment system. Please dispose of these in an environmentally- friendly way.
  • DON’T: use caustic solutions to open blocked drains – use drain rods instead

  • How often should I have the Wastewater Treatment System cleared?
    Wastewater treatment systems need periodic check-ups and proper care to remain healthy and function properly. It is recommended that a wastewater treatment should be emptied once a year; this period may be extended depending on the system’s size and usage. A check should be carried out regularly to see whether or not it needs desludging. The percolation area should also be checked for sogginess or flooding. If the system works well it will not smell.

    Why should I maintain my Wastewater Treatment System?
    Failing wastewater treatment systems can:

  • Cause a serious health threat to your family and neighbours;
  • Pollute groundwater;
  • Be very expensive to repair;
  • Reduce the value of your property;
  • Put drinking water supplies at risk.
  • You are also responsible for ensuring that :

  • The wastewater treatment system is properly maintained and is emptied regularly;
  • The wastewater treatment system access lids are secure and in good working order; and
  • The drains to and from the wastewater treatment system, including the percolation area are free-flowing and free from blockages.
  • What should I look for when purchasing a new property?
    Before buying a home, check that the design capacity of the wastewater treatment system and percolation area will adequately serve the anticipated number of occupants of the house.

    Ask if a maintenance log is kept. Check that the wastewater treatment system is in good structural order and has no history of problems. Ensure that the percolation area is inspected for evidence of flooding. Your Building Society or Bank valuation is unlikely to cover these aspects adequately and a competent surveyor should carry out all these checks and inspections.

    Protecting Our Water - What you need to know

  • Leaflet from the EPA.

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