Decentralized Sanitation Implementation in Different Countries

Decentralized treatment systems present an attractive, sustainable solution over conventional centralized wastewater treatment systems due to their lower cost, operation, and maintenance requirements, especially in developing communities where most of the population lives in dispersed rural communities. This chapter discusses the decentralized wastewater treatment approaches, including septic tanks and pit latrines in different developing countries, along with case studies and implementation challenges. In Vietnam, many towns still rely on family and public pit or vault toilets and bucket latrines that are not connected to a sewer network. The highest number of people practicing open defecation is in India, counting for 59% of the 1.1 billion people who rely on open defecation. The levels of sanitation in sub-Saharan Africa are some of the least developed in the world, where rural communities are rarely covered with any sanitation. Conventional septic tanks were found to be the most common facilities in rural and peri-urban areas in developing countries. The quality of the obtained effluent depends on the composition and type of the treated wastewater, the temperature, the hydraulic retention time (HRT), the tank design (capacity and shape), and the state of maintenance of the tank itself. With a population exceeding 1.4 billion, China is the most populated country in the world, which also experienced fast urbanization. Recently, decentralized wastewater treatment systems in China rely on combining biological and ecological techniques such as combining septic tanks with biofilm processes, activated sludge, or constructed wetlands to produce high effluent quality with a balance of capital and operation costs. The main challenges facing the successful implementation of decentralized treatment systems in developing counties include poor planning, the absence of resources, whether financial, logistical, or technical, which are needed to manage decentralized wastewater and the absence of authoritative regulations for decentralized wastewater treatment.