A Review of Pit Latrine Emptying Technologies for Low-Income Densely-Populated Settlements of Developing Countries
Received Date: December 15, 2018; Published Date: January 18, 2019
A significant proportion of household sanitation needs for low-income densely-populated settlements of developing countries is met by pit latrines, which must be either emptied or relocated when full. New latrine construction cost and space scarcity suggest that pit latrine emptying (PLE) may be the only practical option for the peri-urban poor. PLE, however, has challenges – it is expensive, not well planned, lack of transportation access to disposal sites, often infeasible use of conventional vacuum truck in overcrowded and inaccessible areas, poorly maintained vacuum tankers, and poor households are often missed out of services. One of the major challenges to efficient PLE is technology. Several credible, past and current, literature and bibliographies were gathered to support the review process. This paper explores, through a review, the limitations and challenges of PLE technologies, prompted by the need for more efficient pit emptying options and services. The review reveals that the absence of a suitable, hygienic and low-cost method (preferably mechanical) capable of emptying all pit types remains a technological gap. Developing a solution capable of accessing densely-populated settlements, efficiently emptying and appropriately disposing of dense sludge (including ‘non-pit elements’), yet remaining affordable and easy to operate and maintain, is today’s challenge. The author argues that current innovations so far focus largely on scaling down the conventional vacuum tanker, which may not be the correct way forward, as the fundamental challenge is that less liquid sludge is difficult to effectively deal with. It is recommended that rather than adopting existing current technologies, investment in new and innovative non-vacuum-based PLE technologies that use local materials and based on scooping rather than vacuum action, while drawing lessons from research could be the way forward. The author therefore concludes that a solution may take time, as difficulties cannot be identified and rectified until technologies are developed, tried and tested for a sufficient period. However, as more innovations are developed, tested and improved, progress can be made towards a satisfactory PLE solution.
Keywords: Pit latrine emptying (PLE); Technologies; Low-income High-density settlements; Developing countries