Higher Order Circularity Strategies in Wastewater Treatment: A Case Study from Vernacular Settlements of Sri Lanka

Wastewater treatment methods aim to protect public health and the environment by removing contaminants and preventing water pollution of natural water bodies. Most of the existing treatment methods, inclusive of the costly high-tech methods, are mostly focused on single-objective, end-of-pipe solutions devised under linear production and consumption framework. Such approaches are categorized as lower-order strategies under the concept of circular economic principles which present also a set of higher-order circulatory strategies to effectively maximize resource efficiency whilst minimizing waste generation. This chapter focuses on opportunities for application of higher-order circulatory strategies in wastewater treatment, and demonstrates its viability via a case study from vernacular settlements of Sri Lanka, known as the Ellangava system. An ellangava system is an ensemble of multi-objective, ecologically-comprehensive, expansive subsystems weaved together towards effectively employing cost-effective ecological services to enhance water quality and to ensure its availability throughout the year. We extend the discussion to identify the advantages of subsystems contribution in achieving the ecosystem sustainability goals in wastewater treatment through a roadmap.