Policies and investments that move from mitigation to prevention make wastewater profitable and safe for public health
Sustainable Development Goals target 6.3 calls for improving water quality by reducing pollution, eliminating dumping and minimizing the release of hazardous chemicals and materials, ultimately halving the global proportion of untreated wastewater and substantially increasing recycling and safe reuse globally by 2030.
Achieving SDG 6.3 at country level reveals interesting data points. Lower-middle-income countries (LMICs) on average treat 28% of waste water they generate, while only 8% of wastewater is treated in low-income countries (LICs). Looking at this situation from the perspective of SDG 6, these two country groups are expected to achieve higher reductions in untreated wastewater than high-income countries (HICs) and upper-middle-income countries (UMICs). Assuming that SDG 6.3 is achieved by 2030, there will still be 46% untreated wastewater in LICs, 36% in LMICs, 31% in UMICs, and 15% in HICs.
Wastewater brings considerable value to rural communities in LMICs, and with it, risks that need to be effectively managed. Irrigation with untreated or inadequately treated wastewater supports livelihoods of millions of smallholders who grow food, mainly in urban and peri-urban areas in developing countries. Its use results in damage to the environment and people’s health, and has longer-term implications for sustainable development.
For example, contaminants such as heavy metals, salts and pathogens accumulate in lands irrigated by wastewater, causing degradation and the need for their removal from soil and plant root zones. Heaving irrigation and leaching practices help remove these contaminants, but often shift pollution from wastewater-irrigated land to groundwater.
This scenario exposes urban and peri-urban populations to contaminated groundwater – a dangerous side effect, as this resource is the primary source of drinking water and other domestic water needs. Studies comparing wastewater and freshwater irrigated areas show that environmental degradation and higher rates of water-borne diseases in wastewater irrigated areas than in freshwater zones. For example, children (8-12 years) in wastewater areas have a 75% prevalence rate for gastroenteritis, compared to 13% in freshwater area, bringing a 73% higher health cost per child in wastewater areas.
As large volumes of wastewater in developing countries remain untreated, the investments in treatment facilities have not kept pace with steady increases in population, urbanization and the resulting increases in wastewater volumes.
To better manage and mitigate the negative effects of this trend, affected countries need to make sound economic assessments on the feasibility of investing in wastewater treatment. These analyses need to consider economic, social, societal, health, and environmental benefits. Apart from inadequate public budgets for wastewater treatment, other factors contribute to a wastewater management gap experienced by LMICs. These include a lack of supportive policies, unclear institutional arrangements, and a critical shortage of human resources with the skills needed to address these problems. These shortcomings combine to create the current wastewater treatment problems faced by developing countries today.
The good news is that there is a wealth of practical examples of how to improve wastewater management and reduce its negative effect on populations. Higher income countries point to ‘bright spots’ of good practice for wastewater collection, treatment, reuse and safe disposal of wastewater. For example, the wastewater treatment, use and disposal in North America northern Europe and Japan are subject to stringent effluent discharge regulations for environmental quality. Treated wastewater is used for irrigation in these locations, but the practice is not substantial in humid areas. The situation is different in the arid and semi-arid areas of developed countries, such as western North America, Australia, Parts of the Middle East, and southern Europe, where wastewater after treatment is used primarily for irrigation – a fact of life, driven by increased competition for ever more scarce water, between agriculture and other economic sectors.
Given increasing water scarcity in the world’s semi-arid and dry areas, it is likely that the demand for wastewater as a source of irrigation will increase in these zones of low-income and lower-middle-income countries. And this trend is expected to grow at a pace that is faster the development of technical solutions and institutions that can ensure the safe distribution and management of wastewater.
To best address this situation, several practical interim technical and policy questions need to be considered by decision makers in developing countries. These include: better methods for handling wastewater on farms and in farm communities; better recommendations for crop irrigation and for cultural practices that are suitable for settings where wastewater is the primary source of irrigation; and better methods for protecting farm workers and consumers from the potentially harmful pathogens and chemicals in wastewater, including risk reduction measures such as sanitation safety planning.
It is highly appropriate that wastewater is the focus of World Water Day 2017. It is a call to action for increased treatment of wastewater in all countries, and for its appropriate use and disposal – to break the ‘Catch-22’ cycle of wastewater benefits and related health risks. A change in current practice and policy thinking, in developing countries will spark the change needed to move toward a world free of untreated wastewater.
‘Wastewater’ is not a waste. Rather, it is a valuable source of water, nutrients, and energy. If we do not embrace new thinking, we risk leaving the wastewater challenge to next generations. This would be a shame, especially as we have the knowledge of what is needed to make a fundamental change to current practices. It now needs to be applied!
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