Dolan’s Environmental & Plant Hire

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What happens to wastewater/sewage from my house?

When houses are not connected to a public sewerage system, the wastewater/sewage from a house should be treated by a septic tank and percolation area or an advanced wastewater treatment system. With new house builds the type of sewage system to be used is determined by testing ground/soil conditions at planning stage(Site suitability assessment/Percolation test). Many older houses may not have systems that are up to current standards or are they operating correctly. Annual maintenance and regular emptying are a must for any type of sewage treatment system or septic tank.

How should a septic tank system work?

A modern septic tank system includes a double chamber tank and percolation area. Wastewater is partially digested by bacteria in the septic tank and the effluent then passes through a percolation area where effluent is further purified.

Typical layout of a septic tank and percolation area.

What is a percolation area?

A percolation area typically consists of a system of sub-surface perforated pipes which allow the liquid waste from the septic tank to be absorbed and filtered by the soil. Flexible land drainage pipes, are commonly used by contractors when constructing percolation areas, however these types of pipes are not permitted for percolation areas, and anyone installing these systems should be aware of this and should know what pipes are suitable. Solid 100mm (4inch) pipes perforated typically at 4, 6 and 8 o’clock are recommended to provide even distribution of effluent in the percolation area. A well designed and properly leveled distribution box is also critical for proper percolation. Other requirements for a percolation area are listed in the EPA Code of Practice on Table 7.3 (page 23).

What is a package or an advanced wastewater treatment system?

Package or advanced wastewater treatment systems consist of mechanical aeration or filtration units that enhance the treatment of domestic wastewater. A polishing filter is installed after these types of systems to allow further treatment of the wastewater. These systems may be suitable to be used in some areas where a septic tank system is not acceptable.

The EPA 2009, Code of Practice: Wastewater Treatment and Disposal Systems Serving Single Houses (p.e.≤10) provides general guidance on the location, design, installation and maintenance of both secondary treatment filter systems and packaged wastewater systems.

What is a polishing filter?

A Polishing filters consist of either soil or sand and are used to reduce microorganisms from wastewater. They are used to treat wastewater from advanced treatment systems and constructed wetlands to allow for the discharge of treated wastewater to ground.

Are all sites suitable for septic tanks and other treatment systems?

NO– not all sites are suitable. The following are possible reasons for site unsuitability:

  • A high water table.
  • A slow percolation rate of the soil which would result in ponding on the surface because effluent cannot get away
  • A fast percolation rate of the soil which would result in effluent moving through the soil too quickly without effective treatment.
  • Site restriction issues i.e. not enough space to achieve the minimum separation distances between the treatment system and domestic wells, watercourses, other houses etc.

How do I know if my wastewater treatment system is not working properly?

Some signs that your wastewater treatment system may not be working include the following:

  • Smell of sewage from the general area/location of the tank and percolation area.
  • Slow draining toilets, sinks or drains or backing up of sewage at the inlet.
  • Overflow of wastewater from the tank or ponding of sewage on the percolation area.
  • Discoloration of nearby watercourses (grayish slime growths)

Could my wastewater treatment system pollute my well?

Yes it is possible. If you suspect that your wastewater treatment system is affecting your well firstly you should have your household well checked – this service is provided by various private laboratories companies and by certain local authorities. If you suspect contamination of your well you need to have a full assessment of your wastewater treatment system carried out by a suitably qualified person.

Shows contamination from soak pit entering the household well.

My house is over 20 years old – how do I know if it is working effectively?

Septic tanks installed prior to the 1990’s may not be built to current standards and performance should be checked, Dolan’s Environmental & Plant Hire are available to complete such checks on any system type. Your tank structure should be checked, provide access points for maintenance and Emptying, replace soak-pits and pipes to drains (if present) with a properly designed percolation area or other approved polishing system, always exclude roof and yard water from the sewage treatment system.

What about the use of Soak pits?

In areas with poor soil percolation properties soak pits or direct discharges from soak pits pose a risk to local surface waters. In areas with very shallow soil and high percolation rates soak pits and in particular a cluster of soak pits pose a risk to local ground waters. The use of soak pits significantly increases the risk factor and households using soak pits should consider upgrading their sewage systems.

When buying a house what do I need to do?

Before buying a house you should have the septic tank or wastewater treatment system inspected by a suitability qualified person. Dolan’s Environmental & Plant Hire are on hand to carry out such inspections and offer complete written detail reports. You should ask for installation, commissioning and maintenance records for the sewage system. You should check that the treatment system will be capable of meeting your needs in relation to number of occupants going into the house.

How do I care for my household wastewater treatment system?

You should visually check your system at least every six months and note any ponding of effluent, bad smells or discoloration of nearby drains. If you have an advanced treatment system check the electrical components (pump, blower etc) are operational. Don’t be tempted to turn off the power to save electricity – If there is no air going to the system it becomes an undersized septic tank and treatment is ineffective. You should also check the distribution box i.e. the manhole between the wastewater treatment system and the percolation area to ensure even distribution of effluent and ensure there are no blockages. It is advisable that all sewage plants and septic tank be inspected by trained personnel as the contents of such areas can be very dangerous to an individual’s health, Dolan’s Environmental & Plant Hire are fully trained and equipped to deal with such works safely and in the proper manner.

How often do I need to de-sludge/empty my septic tank or advanced wastewater treatment system?

The EPA recommend that a septic tank is de-sludged/emptied at least once a year but this varies with the system’s capacity and use.

Why do I need to de-sludge/empty my household wastewater treatment system?

If the level of sludge builds up in the tank it may make its way out of the tank and block the distribution box and the percolation area or polishing filter. And if the percolation area or polishing filter becomes blocked it is very difficult to clean and may require replacement – an expensive option if let develop to this stage! Regular maintenance by professional trained personnel is the best prevention to any issues and will ensure your system operates correctly and not cause any pollution to the environment. Dolan’s Environmental & Plant Hire are licensed waste permit holders for removing sewage waste.

What should I do if the sewage system is beeping or making an alarm sound?

This is because there is a fault of some kind with the system that may need specilised attention. Call us today and we can arrange for one of our service team to callout and fix the problem for you ASAP. Karl 087 2513212.

I have noticed ponding in my garden close to my wastewater treatment system what should I do?

First of all you should call Dolan’s Environmental & Plant Hire for a system inspection and to get the system de-sludged/emptied. If it is an advanced wastewater treatment system don’t worry we are well equipped to deal with any domestic system on the market and currently installed in homes around the country.

Ponding of sewage effluent.

Should “grey water” from dishwashers, sinks and washing machines be directed to my wastewater treatment system?

YES – grey water(Sinks, Baths Showers, Washing machines etc) should in all circumstances be directed to the wastewater treatment system. Grey water is also a pollutant and if directed to the rain water system may cause contamination of waters. Take care with house extensions or alterations – don’t connect any wastewater pipes to the rain water disposal system.

Should water from roofs and yard areas be connected to my wastewater treatment system?

NO – Roof and yard waters should not be connected to your wastewater treatment system or septic tank. Clean water should be collected and discharged separately to a local watercourse or soak away.

I want to extend - can I build over my septic tank and percolation area?

Under no circumstances should you build over a septic tank or percolation area. Access to the tank is needed at all times for regular maintenance and the percolation area should not be compacted.
Even with a hard standing area located above a percolation area traffic may damage percolation pipes and result in ponding or escape of untreated effluent.

Can the use of bleach and cleaning agents affect the operation of my wastewater treatment system?

Excessive amounts of bleach and/or cleaning agents will reduce the treatment capability of your system or septic tank as the micro organisms required to treat the wastewater will be killed off. Therefore bleaches and cleaning agents should be used sparingly.

What effects will oils and greases have on my wastewater system?

Oils and grease from cooking that escape down the drain can and will damage your sewage system. Food waste and cooking oils can be recycled, and avoid the use of food macerators or “in-sink disposal units” Excess amount of food, grease or oils will cause blockages, smells, overload your treatment system and damage you percolation area.

What effects could using a macerator or in sink disposal unit have on my wastewater treatment system?

Adding macerated food waste to your wastewater increases the organic strength of the wastewater. This in turn can result in inadequate sewage treatment, blocking of pipes and smells arising from the tank or percolation area.

What records should I keep in relation to my wastewater treatment system?

Best practice and forthcoming regulations will require the following records:

  • Initial site characterisation reports (you can check if your local authority has a copy of this document on the planning documentation attached to your site – contact your local planning section).
  • Planning conditions relating to your wastewater treatment system.
  • Site maps showing exact location of treatment system / septic tank and percolation area.
  • System details including installation details and certification.
  • De-sludging/Emptying records.
  • Service records.
  • Records of checks carried out by the householder.

Is the density of rural housing an issue for water quality?

Yes in some cases – a clustering of wastewater treatment systems in areas with poor soil percolation properties may pose a risk to local surface waters while a clustering of wastewater treatment systems in areas with very shallow soil and high percolation rates may pose a risk to local ground waters. The use of soak pits significantly increases the risk factor and households using soak pits should consider upgrading their systems. It is likely that the use of soak pits will be targeted in new legislation and in measures adopted to protect surface and ground waters.

The law and your wastewater treatment system?

Section 70 of the Water Services Act, 2007 places a Duty of Care on owners of premises and states the following
“The owner of a premises shall ensure that all drains, manholes, gully traps and storage and treatment systems for wastewater, including related accessories, not in charge of a water services provider, which serve that premises are kept so as not to:-
(a) cause, or be likely to cause, a risk to human health or the environment, including to waters, the atmosphere, land, soil, plants or animals, or
(b) create a nuisance through odors.”

For new builds site characterisation must be carried out in accordance with the EPA Code of Practice for Wastewater Treatment and Disposal Systems Serving Single Houses (p.e≤10), 2009. The EPA Code of Practice.

Section 3 of the Local Government, (Water Pollution) Act, 1977 as amended by the Local Government, (Water Pollution) Amendment, Act, 1990 prohibits the entry of polluting matters to waters.

If using a contractor to de-sludge/Empty your wastewater treatment system you must ensure that the contractor holds an appropriate Waste Collection Permit for European waste code 20 03 04. You may be breaking the law if you use an unlicensed contractor to de-sludge/Empty your system.

Where can I get more information?

You can contact Dolan’s Environmental & Plant Hire on 087 2513212 or We are always on hand to help with any questions or issues you may be having with your sewage system.