Choppy waters ahead: dealing with Ireland's wastewater systems

Updated / Wednesday, 8 Nov 2017 17:24

"It is a concern that we are knowingly discharging pollution into our environment, be that into seawater or freshwater"

Opinion: there is a lot to be done in terms of managing Ireland's wastewater infrastructure and it is going to need significant investment from public taxes

According to the Environmental Protection Agency (EPA), huge state investment is needed to manage Ireland's wastewater infrastructure. The agency, which monitors trends to detect early warning signs of neglect or deterioration, has just published a report on 2016 data on urban wastewater treatment.

The report is a useful summary of evaluation of performance of each of the wastewater treatment plants in Ireland. It shows that there is a lot to be done in terms of managing the wastewater infrastructure in Ireland and it is going to need huge investment, which will come from the public taxes.

One of the most striking pieces of information from this report is that 43 areas are discharging untreated wastewater. It is a concern that we are knowingly discharging pollution into our environment, be that into seawater or freshwater.

How we deal with waste water

Treatment plants collect the wastewater generated within our communities, remove the polluting substances and then release the treated water safely back into the environment. Without the treatment processes, wastewater would pose a significant risk to human health. 

In Ireland, a further challenge is linked to the fact that our collection systems are not in a good state. Urban wastewater must be collected before it can be treated and about 30,000km of sewers collect the wastewater. In many areas, the sewers also collect surface water runoff from hard surfaces such as roads, footpaths and car parks. Many of us now pave our gardens, adding to the hard surfaces and run-off. The collection systems must be able to retain the collected flow and transfer it for treatment on a continuous basis.

A concerning fact is the lack of information on the performance of many collection systems, and the lack of maintenance programmes in as many as 24 plants

At times of heavier rainfall, storm water overflows are used to relieve the system of excess flows. In this case, excess flows bypass the treatment plant and discharge to rivers, lakes and coastal waters. In the absence of such overflow mechanisms, the treatment plant, as well as homes and streets, could be at risk of flooding during and after rainstorms. The untreated discharges are usually diluted with volumes of rainfall, but they still have the potential to cause pollution if they are not appropriately managed.

The problem

Only 135 of the 185 large urban areas in Ireland complied with legal standards in 2016. This non-compliance can be linked to any number of factors associated with the old infrastructure, rainfall and stormwater effects and serious maintenance issues as highlighted in the report. Some of these can be addressed in the short term if the willingness is there and can have positive impacts. Others will require significant additional and ongoing investment. The fact that plants are discharging untreated wastewater to the sea in 2017 is startling, as we are growing our focus on the sea for leisure and aquaculture.

"The underlying cause of many failures is a poor infrastructure"

We know from the report that the underlying cause of many failures is a poor infrastructure. Some waste water collection systems are inadequate, some secondary treatment plants were not provided for the waste water collected and further treatment steps to remove nutrients were not provided at some large urban areas.

How can we move forward?

Having a water utility should enable us to manage the infrastructure in a better and more sustainable way. Irish Water must fill the information gaps that still remain on the performance and physical state of waste water collection systems, and the impacts of discharges on shellfish for example.

It is a concern that we are knowingly discharging pollution into our environment, be that into seawater or freshwater

A concerning fact in the report is the lack of information on the performance of many collection systems, and the lack of maintenance programmes in as many as 24 plants. Surely this information and management system is a low hanging fruit in terms of gaining information on the state of the infrastructure? It is where greatest impact can be realised from current investment.  

Coming down the track

Because our wastewater treatment plants are the receiving point for all of our municipal waste water, this is also where the mass-produced chemicals that we use on a daily basis wind up. Studies have shown that many chemicals have an impact on health. These chemicals are things like anti-bacterial products, pharmaceuticals, personal care products, problematic plastics and their additives, as well as pesticides. All of these have potential health impacts, including adverse birth outcomes, inflammation and increased risk of cancer. 


While the immediate concern highlighted in the EPA report is around bacterial contamination and nutrients, there needs to be a plan in place to deal with these chemicals of concern. Some of them are removed during the treatment process, but many re-enter our waters. 

This may challenge us to enforce the "polluter pays" principle to remove as many sources of these chemicals as possible from our water. The producers of the chemicals in question that end up in our wastewater treatment plants  need to pay for their removal in the future.


The views expressed here are those of the author and do not represent or reflect the views of RTÉ