by Monamie Bhadra
In Parkinson and Tayler’s “Decentralized Wastewater Management in Peri-Urban Areas in Low-Income Countries” the authors explains the benefits of designing and building sustainable and decentralized management systems to solve the problem of ineffective wastewater disposal in peri-urban areas, but mostly discusses the constraints in implementation. Although the authors provide a rudimentary framework to build and evaluate such a decentralized system by exhorting capacity-building, they do not present any concrete guidance for operationalization.
Due to rapid and sustained urbanization of cities in developing countries, already resource-strapped governments often fail to provide adequate infrastructures, such as basic sanitation systems, water, electricity, health care, and transportation, among other essentials. Peri-urban areas occupy a liminal zone on the margins of a city, usually in close proximity to industrial complexes, where aspects of both urban and rural life commingle along with the unregulated pollution industry, thus creating social and environmental tensions.
In the case of sanitation, wastewater is discharged onto open ground in abandoned or vacant lots, creating not only cesspools of stench, but also waterborne illnesses as household and surface water and drainage systems are combined, leading to perpetual contamination of clean water. Also, poor peri-urban farmers find it cheaper to reuse untreated wastewater to irrigate crops. Consequently, the inhabitants of peri-urban areas are prone to diseases found in both urban and rural areas: “they get the worst of both worlds.”
Centralized approaches to reuse and treat wastewater have resoundingly failed, as peri-urban areas fall outside municipal boundaries, and as a result, are often beyond the reach of centralized systems. In contrast, decentralization is touted as more effective as it involves transferring central control to local authorities to make decisions about physical design, distribution and operation of wastewater, which will lead to greater accountability and better services. Decentralized approaches to wastewater management are thought to lead to greater stakeholder participation in decision-making and planning, long-term lower financial costs, segregation of waste-water, lower health-risks, and better wastewater re-usage. The authors suggest treating wastewater at the source of generation: the household-centered environmental sanitation approach
Stakeholder participation creates the organization necessary to broker agreements with local municipal authorities. Although NGO’s push for this type of engagement, they often lack the know-how to implement technological systems. In terms of long-term financial benefits, tackling the wastewater problem at the source will defray financial costs of pumping and creating trunk sewers at great distances. Segregating the wastewater from black water (fecal matter and urine) from grey water (effluent water from kitchens and bathroom sinks) can improve water treatment options as well as minimize health risks. Grey water can be used to irrigate with little to no treatments, and black water would be stored in a leach pit. Decentralized operations are also compatible with local need for re-utilizing wastewater for growing crops.
Despite these benefits, a significant setback to creating such treatment facilities is access to large tracts of land, which are most often privately-owned or controlled. A treatment method for black water that requires relatively small areas of land is the anaerobic treatment, the simplest form of which is the septic tank. Other methods include anaerobic waste stabilization ponds, which are very simple, have long retention-spans of waste, and can be integrated into treatment and reuse systems. They also have high concentrations of algae and can support fish such as tilapia. However, this also requires large amounts of land. Constructed wetlands are another option but involve significant pretreatment, and therefore can only be considered as a secondary treatment option.
In addition to technological constraints, lack of management and expertise, as well as lack of institutional cohesion can pose a problem. Therefore, not only should sustainable management of a decentralized wastewater system should be compatible with the knowledge and capabilities of its local users, but successful management requires the concerted coordination and cooperation between government, the private sector, civil society and local communities.
To battle these shortcomings, the authors propose grassroots advocacy to create a cultural need for decentralized wastewater treatment, locally-tailored policy prescriptions, the strengthening of existing institutions to become more flexible to meet the needs of the growing populations in peri-urban areas, and finally, the training and dissemination of technical information to maintain these facilities once built. These recommendations, though laudable, are particularly thin in actually showing how to achieve these goals. The authors are essentially attempting to create a sociotechnological system, in which both technology and culture interact to create a system that is essentially a cultural artifact. This paper would have been stronger if they actually went through case studies where they attempted to put their recommendations into practice.
