Upgrades to Monmouth Wastewater Treatment Works

This investment will allow us to treat and dispose of wastewater more effectively from our treatment works before returning it safely back into the environment.

As a company, we depend on the environment for the water and wastewater services we provide. We take our responsibilities to protecting the environment seriously and we invest around £1 million a day in improving and maintaining our network.

We know that customers want us to do more, especially to help protect the quality of our rivers such as the Wye. This is why we’re working in your area to improve how our assets — such as Combined Storm Overflows — operate.

What’s the problem?

The quality of our main rivers is monitored by Natural Resources Wales. There is concern about the river water quality in parts of the Wye as they’re not achieving what’s called ‘good’ ecological status. This means that there are too many chemicals in the river such as ‘phosphorous’ which can cause algal blooms which can affect the amount of oxygen available in the water and harm wildlife.

What’s causing this?

There are a number of factors which can increase phosphorus levels. This includes how we treat wastewater before it’s returned to the environment. Our modelling on the River Wye for example shows that our assets are responsible for between 25 - 33% of the phosphorus in the main water bodies, with Combined Storm Overflows (CSO) only responsible for 2%. The remainder is caused by other factors such as urban surface water drainage, misconnected drains, agricultural run-off and animal faeces as well as private septic tanks. However, we understand that this is an important matter for local residents and we are committed to playing our part to doing what we can to reduce our impact on the river Wye.

Current work at Monmouth WwTW

There are several phases to this work. The first phase will include work will focus on ensuring that our sewers have enough capacity to deal with the waste that they receive and treats before safely returning it to the local environment. Once this is completed, we will then carry out additional work which will help enhance the treatment process further by removing higher levels of phosphorous which in turn will help boost the local river water quality.

Our compound area will be in place on a small area of Monmouthshire Showground.

Main construction activity will begin from mid January 2024 and will be completed by the end of September 2024.

Once this work is completed, we will need to return to the site to carry out additional work which will help enhance the treatment process further and in turn help boost the local river water quality.

Our River Manifesto

We plan to improve the performance of our assets by targeting our investment to those which have the biggest impact on the environment, whether that’s storm overflows operating more than we’d like or too much phosphorus leaving our treatment works. That is why we have launched our Manifesto for Rivers in Wales which outlines our plans to help improve river quality. This includes:

• Investing £1.5 billion in the decade to 2025 on our wastewater system.
• Investing significantly to improve storm overflows with £25m being invested between 2020-2025 with a further £420m planned from 2025 to 2030.
• Investing an additional £60m specifically to reduce phosphorus in the five failing Special Area of Conservation (SAC) rivers in our operating area.
• Delivering a comprehensive programme of upgrades to our treatment works that will remove 90% of our phosphorus releases by 2030.
• How our business operating model has allowed us to bring forward over £100m additional investment in our wastewater infrastructure accelerating investment that will have a direct benefit in improving rivers in Wales by 2025.