Septic Tanks

Septic tank upgrade in County Galway, Ireland

Case study overview

Summer 2017

County Galway, Ireland

Project Type
Commercial – School

Tricel solution
Fortis septic tank and Puraflo modules

Tricel was specified by site engineer Patrick J Newell to provide a suitable wastewater treatment system for Claran National School. The upgrade to the existing septic tank installation was required following the decision to extend the school. The sewage treatment plants selected were in line with the Irish Environmental Protection Agency (EPA) guidelines.

Tricel provided the specified wastewater treatment plant and worked alongside Riverborder Construction Ltd who carried out the septic tank installation and building work.

The challenge

About Claran National School

Claran National School is located in County Galway, Ireland. Over the last 70 years with the ever-increasing number of pupils attending the school and the changes to legislation and guidelines, it has seen many upgrades. Today,  Claran National School has five teachers and 149 students, these range from junior infant up to 6th class.


The challenges of the project

An upgrade to the existing septic tank installation was required as part of the alterations to the school. Indeed, the existing septic tank system in place was unable to cope with the proposed loading. Patrick J Newell (consulting engineer) from Headford, County Galway, identified a solution to replace the older and now obsolete septic tank.

Three main factors were taken into account for this project:

  1. The capacity for the chosen wastewater treatment solution to cope with a relatively large volume of effluent.
  2. A population equivalent (PE) of 52 was calculated by taking the number of pupils and staff at the school and following the guidelines outlined by the EPA wastewater treatment manual for treatment systems for small communities, business, leisure centres, and hotels.
  3. A compact solution was required to cater for the restricted area available for infiltration of treated effluent.
  4. The project had a short timeline in which to be completed in. Indeed, the works had to be carried out during the holidays to ensure minimum disturbance to the typical day-to-day running of the school.

Tricel solution

How did Tricel help?

Site restrictions, particularly those regarding the limited infiltration area, needed special attention. A bespoke solution was required to meet the uniqueness of the project in term of both the system to be installed and also the timeline for installation.

The solution combined the benefits of a Tricel Fortis septic tank and the use of Tricel Puraflo modules set up as secondary wastewater treatment which was followed by a soil polishing filter. Finally, to cater for the large volume of effluent expected and the restricted area available, the septic system required full pressurisation.


Equipment supplied and installed

Primary treatment: Tricel Fortis 10,800 litre septic tank with an outlet filter

With its proven reliability, efficiency, ease of transportation and price, the Tricel Fortis 10,800 litre septic tank was a perfect choice for this project. Indeed, this tank allows for a capacity of more than 9.8 cubic meters, ideal to deal with both the current and proposed future loadings.

Moreover, the tanks low profile (6.6m long by 1.64m wide with a sufficient depth of 1.9m) required a relatively small excavation for installation. This not only simplified logistics considerably, but it also simplified the installation. The septic tank ’s profile and weight guaranteed minimum ground disruption.

Secondary treatment: 20 x Tricel Puraflo modules

Tricel provided Puraflo modules with a pump chamber and control panel as well as a 5-way indexing distribution valve to disperse the effluent evenly across the Puraflo modules. To dose the effluent equally across the modules, we use a distribution valve which also helps to extend the lifespan of the bio-fibrous peat used in the Puraflo to treat the liquid effluent. The Tricel Puraflo is perfectly suited for intermittent and seasonal flows which were necessary for this project.

Ideal for compact sites, the Puraflo modules can be added to one another when necessary to allow for large PE requirements. The total footprint for the 20 modules in this example is 14m x 4.3m. Furthermore, the plant does not require mechanical aeration; it is the most stable, economical and carbon-neutral solution for this application.

Tertiary treatment: intermittent soil polishing filter

Following the secondary treatment tank, tertiary treatment is applied wastewater. This is required for projects on sensitive soil sites, such as water table protection areas. The combination of different treatment applications results in high-level pathogen and nutrient reduction.

In line with the Irish EPA code of practice, a soil polishing filter covering a surface of 315 sq/m were required to follow the direct discharge from the secondary treatment system (Puraflo).

The final result


All building works, and the Tricel Fortis septic tank installation, got carried out by Riverborder Construction Ltd. Tricel commissioned the tank and installed the required Puraflo modules and pump chamber.

Less than two months had passed from initial inquiry to the installation and commissioning of the wastewater treatment system to be completed.

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Tricel Environment UK

A trading brand of Dewey Waters Ltd.
Heritage Works, Winterstoke Road, Weston-super-Mare, BS24 9AN, United Kingdom.
Tel: +44 (0)1934 422 311