For years, children have happily played in English rivers and streams. Now, with cold and freshwater swimming becoming progressively more popular, guaranteeing clean water for English waterways is more critical than ever. Furthermore, recreation and exercise in rivers and lakes should be possible without the risk of disease and consideration given to the environment.
The Department for Environment, in their 25-Year Environment Plan: 2022 update (pg.52), states that only 16% of England's rivers, lakes and streams classify as having good ecological status, and no single river in England received a clean chemical water quality.
Through remarkable feats of engineering, we have managed to make drinking water safe and must now do the same for English rivers, lakes and streams. Improving the water condition is essential not just for public health reasons but also for the environment.
What causes England's river pollution?
There are three primary sources of pollutants, including raw untreated sewage discharge from wastewater sewage treatment plants. Secondly, the residue from raw animal manure and fertilisers spread onto farmland, carried in the rainwater runoff and via leachate into ditches, streams, rivers, ponds and lakes. Lastly, industrial liquid wastes dumped into rivers contain several chemicals detrimental to the environment.
Raw untreated sewage discharged into rivers
Untreated raw sewage discharged from UK sewage plants dramatically contributes to England's river pollution.
The UK is known for its immense rainfall, and with an ever-increasing population, substantial amounts of water are used daily. Sewer systems and wastewater treatment plants have limited water carrying capacity, and with high water use combined with heavy rainfall, sewers become too full and back up; this causes flooding to streets, homes and businesses. To prevent flooding, storm overflow was introduced as an emergency alternate. The idea is that raw untreated sewage water is released into rivers only during high flood risk situations.
However, data from the Environmental Agency has recently shown that unacceptable amounts of raw sewage water are being released into UK waters, sometimes up to 200 times a year. Exposure to raw sewage has instant adverse effects on humans, including viruses, bacteria, and parasites. It also contains high levels of chemicals that are toxic to fish and other organisms.
Agricultural rainwater runoff and leachate
In agriculture, without the use of fertilisers, it is difficult to replenish lost nutrients back into the soil to grow robust and nutritious crops. Farmers can use different types of fertilisers such as untreated manure from livestock, artificial fertilisers, biosolids or digestate to replenish the soil. However, these products need to be applied only in amounts the soil and crops can absorb and use. If too much is applied beyond the ground's natural absorption capacity, this will lead to runoffs or leaching into nearby streams and rivers.
Fertilisers and raw animal manure entering the UK waterways can cause nutrient pollution, also known as eutrophication. Fertilisers contain the nutrients nitrogen and phosphorus to help plants grow, and just as it does for farm crops, it encourages plant growth in rivers. This excessive plant growth, especially from algae, can reduce water clarity, harm water quality, limit light for the development of other plants and cause plants and fish to die.
Another potential agricultural water pollutant is silage leachate. If silage (green crops) is not appropriately managed, liquid from the silage can seep; this is known as leachate. The leachate contains high nitrogen and phosphorus concentrations and, without due care, can runoff into nearby water sources.
How does industrial waste pollute England's rivers and streams?
As the population continues to expand, so will the demand for goods and products. With more production comes more industrial waste.
The industrial waste can be catastrophic to the environment and human health because industrial waste usually contains non-biodegradable and toxic components. These components include chemicals, pesticides, pharmaceuticals, paints, oils and metals, to name a few.
Improper disposal of industrial wastes has had devastating effects on rivers and streams. Some industrial waste enters the environment through sewage discharge, as liquid waste from plants and factories finds its way into the wastewater system. Also, just like agricultural fertilisers, some industrial waste reaches rivers and streams through runoff. Other industrial waste can be illegally dumped.
How are the UK water pollution challenges being tackled, and what can be done to address these issues in the future?
To address the UK waterway issues, we need infrastructure that is more resilient to increasing population and heavy rainfall, but this comes at an expense meaning more investment into the industry to build better infrastructure is necessary. We must also provide improved regulations and create innovative technology to deal with emerging pressures.
The Anaerobic Digestion (AD) industry has its part to play in keeping the UK rivers clean. Applying digestate or inappropriate application rates at the wrong time of year are two significant causes of fertiliser runoff and leaching. Responsible spreading of digestate at the appropriate application rates is essential to ensure fertilisers are taken up by crops and do not runoff into the water courses.
Storage of silages in proper Silage Slurry and Agricultural Fuel Oil (SSAFO) storage compliant clamps must become standard to prevent water pollution. Adequate management, storage and handling stop silage leachate from reaching water sources.
Proper liquid digestate (fertiliser) storage is essential to reap the most benefits from the product and prevent water pollution. It is vital to have appropriate storage capacity matching the AD plant's output. Digestate spreading is impossible during hefty rainfall, snow or on to waterlogged or frozen ground. Therefore, satisfactory digestate storage solutions are needed to allow farmers to see out wet winters and only spread when the land allows.