What happens when a pit is full?
In South Africa, as part of a drive to provide basic sanitation for all, over two million Ventilated Improved Pit latrines (VIPs) and other similar on-site sanitation systems have been built since the early ‘90s. As many are yet to be built, an emerging crisis is that soon a large proportion of these systems will become full. It is therefore important for Water Service Authorities (WSAs) to have solutions to the emerging challenges and have a good handle on the following aspects: At what rate does faecal waste accumulate in on-site sanitation systems? What are WSAs in South Africa doing about the management of faecal waste from on-site sanitation systems, especially VIPs? What technologies are available, in South Africa and elsewhere, for the emptying of VIPs? What new technologies for VIP emptying are under development and testing? What disposal options are available for faecal sludges? What is the cost of faecal waste management? Is there any evidence for the effectiveness of pit additives? These questions are all significant in contributing to the understanding the sustainability of dry sanitation systems.
The large scale roll-out of basic sanitation in South Africa brings many challenges associated with the emptying up of pits. The problems include poor construction of pits and linings, undersized pits, dumping of solid wastes and the addition of smell retardants and disinfectants. Research by the Water Research Commission (WRC) confirms that pits are filling up faster than expected design life.
In response to these emerging challenges, the WRC commissioned a number of research studies to deal with and provide solutions to this growing challenge. The research undertaken in collaboration with UKZN, Partners in Development and EThekwini Municipality covers aspects related to scientific understanding of processes in pits and the accumulation of faecal sludge, appropriate and innovative techniques for pit emptying, new lightweight superstructures, as well as the safe and beneficial disposal and management of faecal sludge.
Mr Jay Bhagwan, WRC Director for Water Use and Waste Management confirms that municipalities are accordingly facing challenges with planning and budgeting for the emptying of VIPs. The current approaches and technology deployed offers very little opportunities for ease of pit emptying and the environmental and health risks. Municipalities need to understand and predict the rate of sludge accumulation and the emptying methods that may be required. Furthermore, they will have to dispose of the pit contents without endangering the health of residents or the functioning of existing wastewater treatment works, and do so with as little damage to the environment as possible.
“The cost to empty a pit toilet could range from under R700 to over R5 000” says David Still, a WRC project leader currently spearheading the development of technology options for pit emptying.
“EThekwini Water and Sanitation (EWS) is undertaking large scale emptying of VIPs some 45 000 VIPs in the eThekwini area, and the municipality plans are to empty them once every five years. EWS innovatively uses local entrepreneurs to facilitate the emptying and safe disposal of faecal sludges. The average cost per pit emptied to 31 January 2009 was approximately R2 100 or R420 per pit per annum” says Still.
Anyone responsible for the on-site sanitation systems will benefit from a two day seminar that will be held in Durban 14-15 March 2011 .This will be a good platform for experts to share the latest developments with the Southern Africa and other parts of the world.
Contact: Director Water Use and Waste Management: Mr Jay Bhagwan
Tel :012 330 9042 or Cell : 083 290 7232