29 August 2018

Wastewater treatment: A critical component of a circular economy

In a blog Diego Juan Rodriguez, Senior Economist at the Water Global Practice of The World Bank Group, writes about ‘wastewater from waste to resource’. Worldwide, the majority of wastewater is neither collected nor treated. Wastewater is a valuable resource, but it is often seen as a burden to be disposed of. This perception needs to change.

Shifting Paradigms: From Waste to Resource

The way in which we have been managing water and its services is clearly not a long-term solution. Many countries have prioritized investments in water supply, while connection to a sewer system and especially wastewater treatment are lagging behind. Furthermore, traditional investment planning, design, and operating models are linear in nature: water is extracted from a (clean) source, treated, and used, and the wastewater is then treated and discharged in (another) receiving water body. It is needed to shift from the linear model to a circular one focused on reducing water use and consumption and promoting the reuse, recycling, restoration, and recovery of water resources. Realizing this goal will entail rethinking the current wastewater treatment model, so a paradigm shift is needed from waste to resource.

What is needed for the paradigm shift to water resource recovery factories?

Wastewater must no longer be seen as a problem, but as a solution that can help provide sustainable infrastructure services, improves health and wellbeing with financial viability of operators and environmental quality, and strengthen the resilience of the systems. Some basics are needed for good implementation. First of all appropriate legislation is needed, which means that the local situation and receiving water bodies must be borne in mind when drafting legislation. With legislation also institutions to ensure its application and with clear and enforceable sanctions are needed. An integrated situation with intersectoral regulation, policies, and incentives as part of a basin planning framework paves the way for integration of the benefits and impacts of the interventions proposed in multiple sectors, incorporating climate risks and socio-environmental considerations as well. Finally, a complete life cycle analysis that covers financial, environmental (including climate), and social aspects must be used to assess treatment plants and can also be used to approve and justify tariff rates.

The plant’s contribution to the environment must not only be seen as improved water quality in the receiving body. It should also be viewed as a benefit tied to water reuse (e.g., substitution of alternative sources), energy generation from biogas (e.g., climate change mitigation and adaptation), and the use of biosolids as fertilizers (e.g., substitution of synthetic fertilizers). In addition, the positive social impacts of the facility must be taken into consideration during the entire cycle (e.g., jobs generated by the construction and O&M of the plants; increased value of properties owing to the improved quality of the receiving body; an appropriate alternative water source for farmers; low-cost fertilizers when a biosolid program is being implemented; improved health of the population).

Improved wastewater management offers a double value proposition if, in addition to the environmental and health benefits of wastewater treatment, financial returns are also possible. Resource recovery from these facilities in the form of energy, nutrients, reusable water, and biosolids represent an economic and financial benefit that contributes to the sustainability of these systems and of the water utilities operating them. Full size picture.