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Eoghan Clifford: Septic tank legislation makes sense for both householders and the environment

NEW legislation, which provides for the registration and inspection of domestic wastewater treatment systems, including septic tanks, can be regarded as a positive step both for the environment and water resource protection as well as for households with such systems. Such a registration and inspection regime is also necessary if Ireland is to avoid future action from the EU under the Waste Directive.

Septic tank systems, in particular, have received much attention recently but it should be noted that every household with an on-site wastewater treatment system will be required to register that system. Such systems include ‘package wastewater treatment systems’, which have been used in many newer builds over recent years.

The septic tank’s primary role is to allow settlement of solids whereas a percolation areas primary role is the biological treatment of effluent from the septic tank. Thus percolation areas are vital to the performance of septic tank systems and indeed all domestic wastewater treatment systems. Where septic tank systems and the associated percolation areas have been appropriately designed, situated, installed and maintained they provide a robust, efficient and cost-effective method of treating domestic wastewaters.

Greywater, or water from showers, sinks, washing machines etc., should be passed through the wastewater treatment system (including septic tank systems) as these are designed to cater for such flows. Also, generally speaking, once a household is reasonably normal in its use of detergents and bleaches there should not be an issue when greywater enters the wastewater treatment system.

The proposed inspection regime has not been announced, and this, when published will be of great interest; for example how will percolation areas be inspected?

Where minor remediation is required it could, for example, include desludging the septic tank or primary settlement tank, unblocking pipework or replacing faulty equipment; entailing relatively small costs. In a few cases, major upgrading may be required and this can entail significant costs. In such cases, where the householder is making a genuine effort to comply, it would make sense that relevant agencies will take a practical approach to support their efforts. Once remediation is complete regular maintenance should prevent further problems from occurring.

Further to the legislation, it is critical that the issue of the design, installation and maintenance of domestic wastewater treatment systems is addressed. Such systems should be designed by qualified personnel (Chartered Engineers who have appropriate insurance in place, for example). This will ensure, where major remediation is required or a new system is installed, the householder can be satisfied that they have been expertly advised and that the system being installed is fit for purpose.

Most householders would be concerned to know their system may be causing environmental, or public health issues and thus the recent legislation can be seen as a positive development, which can give the householder confidence they are not causing damage to the environment or public health.

Dr Eoghan Clifford is a lecturer in Civil Engineering at NUI Galway