On-site Disposal Problems
It is well documented that the wide scale use of septic tanks
over recent decades has contributed to the pollution of groundwater
throughout the country. Infact, recent EPA figures claim that about
30% of groundwater samples showed bacterial contamination, with
11% being grossly contaminated.
At
least part of the responsibility for this pollution must rest
with poor wastewater treatment or disposal facilities, particular
badly designed and inappropriate septic tank systems. Despite
this problem septic tanks are still being widely used as the preferred
form of wastewater treatment and disposal even with the
introduction of more advanced sewage treatment systems into the
market.
It
is important to outline the difference between a septic tank and
a wastewater treatment system. A conventional septic tank processes
wastewater by anaerobic activity (i.e. without air) and
solids settlement only, and is totally dependent on the soil and
disposal system to treat the wastewater prior to entry into the
groundwater.
A
wastewater treatment system on the other hand, incorporates
both anaerobic and aerobic (with air) processes ensuring that
the treated sewage is of a very high standard. The wastewater
is treated to such a high standard that it can be safely disposed
into the soil and receiving groundwater.
Wastewater
treatment systems understandably are more expensive than basic
septic tanks though the end result is a considerably superior
quality of effluent. Most treatment systems have been tested and
certified by the Irish Agrement Board to satisfy building requirements
while some systems even have been tested and approved to the more
stringent European EN12566 standards.
Obviously
as wastewater treatment systems have a mechanical and electrical
input for aeration and disposal requirements they do need periodic
service and maintenance. However, the same applies to conventional
septic tanks. Despite not having pumps or aerators septic tanks
do need periodic inspection and maintenance including desludging.
Failure to do this leads to blocked percolation areas, ponding
of sewage in gardens, smells and fly nuisance, and of course,
pollution of groundwater.
To
halt this decline in standards DETA has called for purchasers,
installers and Authorities to adopt a more proactive, informed
and constructive approach to the issue of wastewater treatment
and disposal. This would include:
- Local
Authorities setting their own minimum acceptable standards for
performance, energy use, level of maintenance etc. for installers
of septic tanks and wastewater treatment systems, and impose
an effective policing system.
- The
Department of Environment adapting new regulations on septic
tanks and treatment plants in line with the requirements of
EN12566.
- The
EPA publishing its revision of the draft guidance document "Treatment
Systems For Single Dwellings" emphasising the benefits
of wastewater treatments systems over septic tanks.
- Homeowners
insisting that their insurers include treatment systems or septic
tanks in the construction and homeowners defect insurance.
- Users
of systems becoming more informed and taking the necessary action
against the designer, installer, seller etc. when faced with
problems such as obnoxious odours, ponding of effluent, fly
or insect infestation, frequent costly pump-outs, property devaluation
etc.
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