Wastewater - Turning Problem to Solution

Action area 2: Prevent and reduce contamination in wastewater flows

help reduce input of contaminants into wastewater in the first place. All require some degree of change in behaviour or business practice.

The fewer pollutants that are introduced into wastewater, the easier and cheaper it is to treat the wastewater and recover safe, usable resources. Clean, safe water is characterized by physical, chemical and biological quality parameters. As water is used, the quality deteriorates, for example through the addition of nutrients, chemicals, pathogens, heat and microplastics. In addition, new and emerging contaminants, such as pharmaceutical and personal care products, hormones, dioxins, pesticides, nanomaterials and surfactants are increasing all the time (Ahmed et al. 2021). If not adequately treated, these contaminated flows pose a threat to the safe reuse of water further downstream as well as to the biodiversity and function of the receiving ecosystems (Jones et al. 2022; van Vliet et al. 2021). Pathogens and nutrients, both prevalent contaminants in wastewater, result in waterborne disease and eutrophication. Conventional treatment processes are not designed to completely remove many of these emerging contaminants, resulting in detrimental long-term and in some cases yet-unknown impacts on human and ecosystem health. Mahjoub and Chmengui (2021) demonstrated the spread of pharmaceutical compounds in the coastal environment in arid and semi-arid countries. In the Baltic Sea region the release of contaminants such as pharmaceuticals is concerning due to the low flushing rate and long retention time of these pollutants, and has been the subject of regional action through the Helsinki Commission (United Nations Educational, Scientific and Cultural Organization and the Helsinki Commission 2017). To assess the presence and to evaluate potential impacts, monitoring programmes are required at the country and regional levels. Given the wide range of contaminants and their ubiquity, preventing the input of contaminants into water or separating and eliminating them prior to their discharge or before reaching the wastewater collection system are considered to be more efficient and less costly approaches than collecting and waiting to treat the problem as an end-of-pipe approach. Preventing input of contaminants

Reducing the input of contaminants in the agriculture sector

• Applying smart agriculture innovations to ensure efficient use of nutrients and any chemical inputs. This can range from low-tech solutions, using crop rotation to control nutrient deficiency, rainwater harvesting, through to the application of high-tech solutions such as robotics, digital communication between machinery (the Internet of Things), artificial intelligence and cloud computing to reduce the quantities of chemicals and fertilizers that need to be applied. • Implementing science-based nutrient management strategies to reduce environmental losses. Monitoring soil quality before application can inform what additional nutrients are needed as well as the most appropriate timing and rate of application in the right places. • Using cover crops to return nitrates to the soil and reduce the need for additional fertilizer. • Moving towards no-till field management strategies. • Optimizing the use of veterinary medicines and antibiotics for livestock breeding. The overuse of antibiotics and artificial growth hormones in industrial farming results in the release of their residues into soil, groundwater and surface waters (Zandaryaa and Mateo Sagasta 2018). • Phasing out use or self-regulating certain contaminants, for example through the Wastewater Zero call to action by the World Business Council for Sustainable Development (WBCSD 2020). • Investing in the development of suitable alternatives to products that are less harmful, e.g. in plant-based exfoliating skincare products to replace plastic microbeads. • Implement zero liquid discharge systems allowing for the recovery of chemicals, e.g. as implemented in textile, chemical and power industries (Jahan et al. 2022) and applied to commercial complexes such as hotels and malls (Mubarak et al. 2018). Reducing the input of contaminants from industry

There are a wide range of potential actions at the household, municipal, industry and farm level that can

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