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Chapter 5: Inland and Marine Waters
Domestic Waste Water Treatment
Systems
A national inspection programme for septic tanks
highlights room for significant improvement in
how people manage domestic waste water treatment
systems.
Following the introduction of legislation dealing with the
registration and inspection of septic tanks in 2012 a national
inspection plan has been implemented [Water Services
(Amendment) Act, 2012]. By the end of 2014, a total of
1,559 inspections had been carried out (EPA, 2015c). One
of the main findings from the inspections is the lack of
general routine maintenance of systems. The low level of
de-sludging of tanks and issues surrounding the operation
and maintenance of systems were the main reasons for
inspection failures (Figure 5.12). A reversal of this trend in
many cases requires simple actions by homeowners rather
than a structural change to the waste water treatment
system. Of relevance to water protection is that 16% of all
systems inspected failed because either they were unlicensed
discharges to surface water or because they had inadequate
soil thickness for attenuating pollutants. These types of
situations are difficult and/or expensive to correct.
Tackling Point Source Pollution
Urban Waste Water Treatment
Despite ongoing improvements in urban waste water
treatment plants and the effluent discharged is not up
to standard in many locations.
Waste water must be treated prior to being released back
into the environment in order to remove contaminants
that could otherwise pose a risk to the environment or
public health. The EU Urban Waste Water Treatment
Directive of 1991 (91/271/EEC) sets out requirements for
the collection, treatment and discharge of urban waste
water, with the objective of protecting the environment
from the adverse effects of waste water discharges.
The EPA is the environmental regulator responsible for the
licensing, authorisation and enforcement of urban waste
water discharges. The EPA has issued over 1,000 waste
water discharge authorisations to date
17
. Irish Water/Uisce
Éireann is the national water utility responsible for the
provision and development of water services, including
the collection, treatment and discharge of urban waste
water. These responsibilities, together with duties to
comply with the requirements of all waste water discharge
authorisations issued by the EPA, were transferred from the
local authorities to Irish Water at the beginning of 2014.
17 EPA Licence or Permit Document Search Facility: EPA: Environmental
Protection Agency, Ireland
In 2014, a total of 12 (7%) large urban areas did not meet
the Urban Waste Water Treatment Directive requirement
to provide secondary (biological) treatment (EPA, 2015a).
Seven large urban areas did not comply with the Directive’s
requirement to provide infrastructure to reduce nutrients
and discharged effluent that did not meet nutrient quality
standards. Untreated sewage was discharged from 45
areas, mostly estuaries or coastal areas. Twenty-seven of
these are located in counties Cork, Donegal and Galway.
Three of these raw sewage discharges were treated by
the end of 2015, but one extra location was added to the
list. In terms of effluent quality, 143 (82%) large urban
areas complied with the mandatory EU effluent quality
and sampling standards. Just 24% of the waste water load
discharged into sensitive areas from large towns and cities
complied with mandatory EU nutrient quality standards, up
from 17.5% in 2013. This is well below the EU average of
88% compliance for nutrients (EC, 2016). Dublin and Cork
were the major contributors to this low rate of compliance.
Although BOD (biological oxygen demand), COD (chemical
oxygen demand) and TSS (total suspended solids) are still
far from compliance with effluent quality and sampling
standards in the Directive, the recent trend of improving
compliance continued in 2014, as illustrated in Figure
5.13, which shows national compliance rates at large
urban areas for the years 2009 to 2014.
When the performance of waste treatment plants is
examined, it is apparent that treatment of waste water
at coastal and estuarine locations needs improvement, as
investment in these areas has lagged behind discharges to
freshwater surface waters. Updated data for 2015 shows
that 36 of the urban areas discharging untreated sewage
and 10 large towns or cities (with some type of treatment)
that failed the Directive’s effluent quality standards
discharge to estuarine or coastal locations (EPA, 2016d).
EPA Water Research Programme
The EPA Water Research programme has a strong focus
on policy and has been driven by national regulations
and European directives. A sustained Water Research
Programme is an essential component of Ireland’s
role in protecting its water resources and meeting its