Phosphorus is an element essential for life. Concerns regarding long-term security of supply and issues related to eutrophication of surface waters once released into the aquatic environment have led governments to consider and apply measures for reducing the use and discharge of phosphorus. Examples of source control include legislation to reduce phosphorus use in domestic detergents. This research shows that other domestic sources of phosphorus also contribute significantly to the domestic load to sewer and that overall, domestic sources dominate loads to sewage treatment works. Estimates provided here show that although the natural diet contributes 40% of the domestic phosphorus load, other potentially preventable sources contribute significantly to the estimated 44,000 tonnes of phosphorus entering UK sewage treatment works each year. In the UK, food additives are estimated to contribute 29% of the domestic load; automatic dishwashing detergents contribute 9% and potentially increasing; domestic laundry 14%, including contributions from phosphonates, but decreasing; phosphorus dosing to reduce lead levels in tap water 6%; food waste disposed of down the drain 1%; and personal care products 1%. Although UK data is presented here, it is anticipated that similar impacts would be expected for other developed economies. Consideration of alternatives to all preventable sources of phosphorus from these sources would therefore offer potentially significant reductions in phosphorus loads to sewage treatment works and hence to the aquatic environment. Combining all source control measures and applying them to their maximum extent could potentially lead to the prevention of over 22,000 tonnes-P/year entering sewage treatment works.

This chapter provides an introduction to the topic of aquatic pollution and looks at the major sources and pathways of pollutants to the environment from agriculture and industry. The section on agricultural pollution focuses on the use of fertilizers and pesticides. Industrial pollution covers a large topic and so three groups of pollutants are examined to provide an overview of the key issues faced within this sector.

Pharmaceutical residues are of environmental concern since they are found in several environmental compartments, including surface, ground and waste waters. However, the effect of pharmaceuticals on ecosystems is still under investigation. To date, the removal of these micropollutants by conventional treatment plants is generally ineffective, in addition to producing a considerable carbon footprint. In this sense, to achieve the current zero-pollution ambition, a reduction in the negative impacts of chemical substances such as pharmaceuticals on the environment must be aligned with initiatives such as the European Ecological Compact, Environment Action Programme, and Circular Economy Action Plan, among others. This review provides insight into the key drivers for changing approaches, technologies, and governance of water in Europe (Germany, Switzerland, and the UK), including improving wastewater treatment in sewage treatment plants for the removal of pharmaceuticals and their carbon footprint. In addition, an overview of emerging low-carbon technologies (e.g., constructed wetlands, anaerobic membrane bioreactors, and enzymes) for the removal of pharmaceuticals in sewage treatment works is provided. In general, the removal efficiency of pharmaceuticals could be achieved up to ca. 100% in wastewater, with the exception of highly recalcitrant pharmaceuticals such as carbamazepine (removal <60%). These technologies have the potential to help reduce the carbon footprint of wastewater treatment, which can therefore contribute to the achievement of the Europe Union’s objective of being carbon neutral by 2050.