My experience of the CWBE Autumn 2025 Sampling Campaign, by Kheti Mhlongo

This past November, I joined several other PhD students and CWBE postdocs to take part in our seasonal river sampling campaign. We investigated the water quality of the river Avon at two locations, near the Radstock wastewater treatment plant and another wastewater treatment plant near Paulton. This is done routinely to measure and monitor the health of the river.

What is our river sampling campaign all about?

To examine the potential effects that the wastewater treatment plants have on the surrounding environment and the seasonal changes of the river. We measure the flow, depth and take 24-hour composite samples of the river for eight consecutive days, this provides vital information for us to take into account when processing data for analysis and modelling. The flow and depth of the river can change with weather conditions with rain increasing both measures as the seasons change. Additionally, the flow and depth changes of the river can impact the surrounding environment including habitats and farmland.

Measuring our impact on the environment

Each location is measured at two sites: upstream and downstream of the wastewater treatment plants, to measure the potential impact of effluent on the river. By subtracting the flow measurements of the upstream location from the downstream location, the flow of the effluent can be modelled. However, other factors such as rainwater need to be considered as well, this is where out statisticians and mathematicians come in.

Other measures of water quality such as ammonia and acidity/alkalinity can be investigated as well. These contribute to our understanding of how local communities impact the surrounding environment. At CWBE, we take on a multifaceted approach to monitoring community and environmental health, such as estimating pharmaceutical usage trends in the population or investigating the risks of antimicrobial resistance in the local ecosystem.

Team spirit and skill acquisition

Measuring these parameters in the river is no easy task! As we have new members to our team, we also had a training to make sure the measurements taken are accurate. A few weeks before our sampling campaign, we had an induction at the Paulton site to learn how to take flow measurements and how to use the prescribed autosamplers. This process meant that over the course of the sampling campaign (eight days), our team could work effectively in shifts to take time sensitive measurements.

Final thoughts

Going out into the field for sample collection was a different experience for me in the most fascinating way. Like many of my colleagues, I have mostly done wet lab work before, so this was an adventure for me. I learned a lot from this experience, about how wastewater treatment plants work, what communities contribute to sewage and river health. This, combined with the collaboration required to produce a complete dataset from this campaign, showed me just how multidimensional applied science projects can be. We needed a team of people to make all the measurements needed in a timely manner.

Additionally, the idea that this data contributes to a multidisciplinary project that prioritises community and environmental health fills me with joy and pride for taking part. This data provides more context to our findings at CWBE, especially in regard to monitoring environmental health, giving us a more comprehensive picture. I look forward to knowing what this information this gives us.

Until the next sampling campaign!

A special thank you to Wessex Water for use of their autosamplers and to Dr. Nicola Ceoletto for arranging the training/campaign.

Written by

helena

December 3, 2025