Wastewater - Turning Problem to Solution

2021). A large fraction of consumed antibiotics (30–90 per cent of intake) is excreted in faeces and urine (Du and Liu 2012). The One-Health concept recognizes the link between human and animal health and the environment (WHO 2021). AMR is a key priority for the One Health approach, as AMR is due to the poor management and excessive use of antimicrobials in livestock and people. Wastewater treatment plants are known to be potential sources of AMR, as they receive a variety of human and animal waste streams, including those from hospitals. Numerous studies have investigated the occurrence and prevalence of AMR in treated wastewater. There is abundant evidence that conventional treatment does not always effectively remove many contaminants, including antibiotics, antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). ARB and ARGs are not yet fully understood in the contribution of wastewater reuse to the dispersal of antibiotics. Recently, Slobodiuk et al. (2021) reviewed the impact of both treated and untreated wastewater used for irrigation on adjacent areas. They found that irrigation with untreated wastewater was clearly associated with increased ARBs and ARGs in soil. But they found that the results for the use of treated wastewater varied, with about 50 per cent of the studies showing an increase in the abundance of ARBs and ARGs in soil and adjacent waterways. A European study found similar variability. Cacace et al. (2019) examined the receiving waters of 16 wastewater treatment plants and found that the abundance of ARGs was inversely correlated with the amount of biological treatment, specifically the sedimentation of activated sludge (a secondary wastewater treatment process). Other studies have looked at treatment options for effective removal of ARBs and ARGs (reviewed by Pant et al. 2022). The choice of advanced treatment technologies will depend on the intended use of the treated wastewater (level of removal efficiency required), the investment required and the economic viability (figure 2.18). Assessing the risk and taking action to prevent the release of antibiotics, ARB and ARGs from wastewater treatment plants has gained momentum. Despite the lack of a practical regulatory framework, preventive measures promoting reduction at the sources (at the point of release, upstream of the wastewater treatment plant), education and public awareness for appropriate antibiotic consumption, and controlling antibiotic waste disposal through adequate handling and management of medicinal wastes are recommended strategies.

Increase of antimicrobial resistance It is estimated that between 2000 and 2015, human antibiotic use, expressed as defined daily doses per 1 000 people per day, increased by 39 per cent (Klein et al. 2018). According to WHO, antibiotic use has increased 91 per cent worldwide and 165 per cent in low and middle income countries during the same period (figure 2.17). The increase in use of antibiotics both in humans and animals has driven a rise in AMR. Modelling suggests that in 2019, there were an estimated 4.95 million deaths associated with AMR, with the highest percentage in western sub-Saharan Africa (0.27 per cent of the population [Murray et al. 2022]). However, antibiotic use is vital to combat certain diseases and prevent deaths of millions of people. More people in low and middle income countries still die from lack of access to antibiotic medications than from AMR (Sriram et al. These results suggest that the children going to the field to play or work with their parents in wastewater irrigated areas seem to have a higher risk of getting waterborne diseases than the children from other areas. It was also found that the annual health cost per child was 73 per cent higher in wastewater irrigated areas than the health cost for the same age group in freshwater-irrigated areas. Monitoring water quality and hygiene education for the appropriate handling of wastewater are important where untreated or inadequately treated wastewater is being used. The potential impact of wastewater-irrigated areas on the health of children is an issue that deserves greater attention, especially considering the widespread use of untreated or inadequately treated wastewater for agricultural irrigation. A study conducted by Grangier, Qadir and Singh (2012) investigated the health implications of wastewater irrigation on children between the ages of 8–12 years in the peri-urban Aleppo region of Syria. The study compared the occurrence of waterborne and non-waterborne disease in villages within the wastewater-irrigated area with those from an area irrigated with fresh water. The study also investigated eczema, which may stem from water or non-water sources. Gastroenteritis (a waterborne disease) and eczema had significantly higher prevalence rates in wastewater-irrigated areas as compared with freshwater-irrigated areas. Box 6: Health implication for children exposed to the use of untreated wastewater

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