Wastewater - Turning Problem to Solution

Environmental flows The overextraction, mismanagement and pollution of water risks undermining the ecological integrity of freshwater, estuarine and consequently marine environments. Assuming the treated effluent meets appropriate standards for treated wastewater and effluent discharges, wastewater can be used to maintain, restore or enhance water flows in streams and rivers, and water levels in lakes and wetlands

(EU 2016; EIB 2022). This can sustain aquatic biodiversity and provide benefits for the environment and people. It has also been noted that appropriately treated wastewater can be used to recharge aquifers and protect groundwater from saline intrusion (EU 2016). However, unintentional aquifer recharge with untreated or insufficiently treated wastewater still occurs in many areas, which needs special attention as it can lead to human and environmental health risks (Zandaryaa and Jimenez-Cisneros 2017).

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Nutrient recovery

Oladoja 2021). The nutrients of primary focus are those that support plant growth –nitrogen (N), phosphorus (P) and potassium (K). These are valued for ensuring global food security, especially with the skyrocketing cost of fertilizer since 2020, due to global recession following the pandemic, exacerbated by the conflict in Ukraine, impacting production and supply chains (FAO and WTO 2022). Qadir et al. (2020) calculated that the volume of municipal wastewater (see box 4) generated annually contains 16.6 million tonnes of nitrogen, 3 million tonnes of phosphorus and 6.3 million tonnes of potassium. Depending on the

There are many reasons to develop nutrient recovery and reuse from wastewater, including addressing the social, environmental and economic costs of nutrient pollution. Controlling nutrient pollution can reduce eutrophication and the risk of dead zones developing (Schindler et al. 2016). It also has the potential to reduce reliance on conventional chemical fertilizers (Saliu and Oladoja 2021). Nutrients can be recovered from a range of wastewater sources, including agricultural (aquaculture, animal production, abattoirs), industry (tanneries, yeast industry) and municipal (laundry, human urine, sewage) (Saliu and

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