Drip Infiltration Systems

Drip irrigation is the most efficient method of distributing wastewater to infiltration areas. It allows effluent to be dispersed in the biologically active soil zones a few inches below the surface without ponding, water contamination or smells. It also allows the efficient reuse of the treated water along with its beneficial nutrients for landscaping in a controlled and environmentally friendly fashion. We supply Geoflow pressure compensating drip tubing which is treated for root intrusion and an antimicrobial coating to inhibit biological growth on the inside walls of the tube and on the emitters.

Drip irrigation (known as drip distribution or drip feed systems) take up less infiltration area and can be used in areas with shallow unsaturated depths of soil. This results in a smaller land requirement for percolation areas so are ideal for small sites –both domestic and commercial.

How it works

A typical drip design is to insert the dripline into the existing soil using sub-surface pipe insertion machinery such as a mole plough or similar. The drip line is inserted at a depth of 150- 200 mm below the existing ground level. Grass should be mowed regularly in dry weather with light mowing machinery.

The dripline has a series of emitters spaced at 600 mm intervals in the drip tubing which are moulded into the dripline at the time of manufacture. Each emitter releases very small quantities (0.03 litres/minute) of water which drips into the soil when the design pressure is reached.

Drip can be used on large and small systems including existing problem sites. Drip systems will maximise the treatment capacity of the soil on sites with shallow or excessively free draining soils and will improve soil infiltration in the slow draining soils due to the very small controlled doses released from each emitter orifice of 0.03 litres/minute.

Key benefits are:

• Can be used on difficult sites- high water tables, tight soils, rocky terrain, steep slopes, around existing buildings and trees.
• The system requires no gravel. It is easy to install directly into indigenous soils and the natural landscape can be maintained.
• Shallow installation by mole plough or similar maximises the use of “good” topsoil and installation depth to limiting soil horizon or watertable.

Drip can significantly reduce the amount and cost of fill material required. Drip distribution of wastewater (drip-feed) to infiltration areas is included in the Irish EPA Code of Practice 2009 under other infiltration systems. Its use is at the discretion of each Local Authority.

A growing number of drip installations have been installed - including two by Trinity College under the EPA STRIVE program in co-operation with Ash Environmental.

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FAQ's

Where do I start if I need a new sewage treatment system in an unsewered area?

The starting point for new construction is to have the site assessed for suitability to treat the sewage and other wastewater.

If the site assessment finds the site is suitable then a design for the integrated components of the treatment system (called an onsite treatment system) can be sought from the site assessor or from a wastewater system designer who may be an engineer, architect, surveyor or other specialist wastewater company. We can assist in recommending a certified site assessor or system designer.

Are onsite treatment systems suitable for commercial establishments or housing developments?

Yes. The process is as outlined above but large systems will require more specialised assessment and designs due to the larger volume of water and greater risk of pollution involved. There are new types of pressurised infiltration systems available now that may be particularly cost effective and space saving which we in Ash Environmental specialise in providing. We can provide the integrated system design with project management through to final certification of the scope of work.

Can I mix and match different elements of the treatment system?

Some components can be substituted for other similar ones. However, when properly designed the integrated system is customised to the specific site requirements such as proximity to waters and shallow or free draining soils and importantly with the type of infiltration system.

What types of infiltration systems are there?

Infiltration systems include gravity percolation areas and pressurised (pumped) systems such as low pressure PVC pipe systems dosing the wastewater to mounds, sand filters or other polishing filters. A new interesting technology called drip infiltration is becoming very popular and is likely to grow following a successful Trinity College/EPA evaluation project. Click here for details in the paper New Pressurised Onsite Wastewater Infiltration Systems. Ash Environmental specialise in pressurised infiltration systems design and project management including pressure PVC pipe, LPP and Drip systems.

Do I need planning permission?

New systems will always require planning permission. Modifications to existing systems or percolation areas may not require planning. Your local authority environment section will advise you if in doubt.

Will I need a septic tank or a secondary treatment system?

A septic tank system including percolation area (gravel and pipe finger trenches) is the most cost effective system if your site assessment is suitable.

How can I remediate my old soakaway or percolation area?

There are some useful suggestions contained in the paper called “Practical Ways to Improve Septic Tanks and Percolation Areas”. Click here to download it.

Other useful information: Frequently Asked Questions (FAQ’s) Wastewater treatment systems for single houses

What you need to know about your septic tank leaflet

A good general guide to onsite treatment systems on Sligo Co Council website

Domestic Wastewater Advice and Guidance video

Remediation and Replacement of DWWT System 

National Inspection Plan Domestic Waste Water Treatment Systems  

Find out what to expect from your inspection video 

Code of Practice: Wastewater Treatment for Single Houses

Urban Waste Water Treatment in 2012

EU Water Framework Directive Monitoring Programme – EPA

A-Z Glossary of Environmental Terms