Percolation Types in Ireland

Pressurised Polishing Filters, also known as a Low Pressure Pipe System (LPP) is a very common method of distributing treated effluent from a sewage treatment system into the soil. The effluent is pumped from the Sepcon BAF to a either a splitter valve or a manifold which in turn distributes the effluent trough a number of 32mm laterals to disperse the effluent evenly over the bed. 25mm Pipes can also be used subject to good design as the smaller pipes can block faster as a result of poor maintenance.

A Trench Soil Polishing Filter (TSP) is a more traditional method of distributing effluent from a septic tank or sewage treatment system.  This is option is more ideal for sites with a topography that favors a gravity outlet from the septic tank or sewage treatment system.

Drip Irrigation Systems can be used as an alternative method of distributing effluent into poorly draining soil. A detailed study conducted by Trinity College Dublin confirmed the suitability for drip on most sites in Ireland. Drip was found to be the most viable in sites with poor soakage while having about 600 to 800mm deep of soil depth. As mentioned, a drip system has the advantage of working well on sites with limited soakage as the effluent is evenly distributed across a large network  of high pressure pipes with small emitters that let the effluent out at a controlled pace. Due to the complexity of the design, drip dispersal systems need to be designed and fitted by the same company such as Sepcon for example.

Sepcon FiberPodsTertiary Modules are highly effective way to treat the waste water from the Sepcon BAF system to a very high standard prior to final discharge into the soil and are ideal for restricted sites as they have a small footprint. FiberPod modules are generally a suitable option on sites with limited available area and/or sites with poor soakage. The FiberPods are delivered and placed by truck mounted crane. Fiberpods have a distant advantage over coconut (coco) systems as the fibers are synthetic and don’t rot so are ever lasting. This results in huge saving and more reliability.

Tertiary Sand Polishing Filters treat the waste water from the Sepcon BAF system to a higher standard prior to final discharge into the soil and are ideal for restricted sites as they have a small footprint. A sand polishing filter is generally the most viable option on sites with limited available area and/or sites with poor soakage as the effluent discharged from a sand polishing filter does not form a biomat or sludge layer which can impede the rate of soakage into the ground. Disadvantages with sand filters is mainly the sand. Some contractors using poor quality sand has given the sand filter a mixed name throughout Ireland.. For a sand filter be be a success, the quality of the sand is the key.

Coconut Tertiary Modules or Peat Tertiary Modules use either Coconut husk or peat fiber to treat the waste water from the Sepcon BAF system to a high standard prior to final discharge into the soil and are ideal for restricted sites as they have a small footprint. Coconut modules are generally a suitable option on sites with limited available area and/or sites with poor soakage as the effluent discharged from a sand polishing filter does not form a biomat or sludge layer which can impede the rate of soakage into the ground. The main disadvantage of both coconut husk and peat fiber is the longevity is poor. The lifespan if the media is typically 10 to 12 years and the replacement cost is high.