An investigation of the effect of pit latrine additives on VIP latrine sludge content under laboratory and field trials

BF Bakare,CA Buckley,KM Foxon,CJ Brouckaert

doi:10.4314/wsa.v41i4.10

Abstract

Sludge content in VIP latrines is degraded mainly under anaerobic conditions and the process is relatively slow. At varying stages of digestion within pit latrines, sludge accumulates and odour and fly nuisance may occur which could pose risks to public health and the environment. Management of accumulated sludge in pit latrines has been a major problem facing a number of municipalities in South Africa and is also a global issue. Manufacturers of various commercial pit latrine additives claim that by addition of this product to pit content, accumulation rate and pit content volume can be reduced, thereby preventing the pit from ever reaching capacity. This paper presents a comprehensive study conducted to determine the effects of additives on pit contents under laboratory and field conditions. By conducting both laboratory and field trials, it was possible to identify whether there is any acceleration of mass or volume stabilisation as a result of additive addition, and whether any apparent effect is a result of biodegradation or of compaction. The results indicated that neither laboratory trials nor field trials provided any evidence that the use of pit additives has any beneficial effect on pit contents. The reasons why additives seem to not have any beneficial effects are also discussed.

Highlights

In South Africa, where the provision of adequate sanitation facilities to all is considered to be a fundamental human right, it is important to look at the provision of sanitation facilities holistically, and to derive scientifically-based approaches towards managing these sanitation facilities
Despite the results presented in the scientific literature which suggested that pit latrine additives are not effective for reducing accumulation of sludge within a pit, a number of role players in the industry still believe that the use of these products might be beneficial
The results for jars treated with additives are shown as lines, whereas the results for the controls are shown as point symbols

Summary

Introduction

In South Africa, where the provision of adequate sanitation facilities to all is considered to be a fundamental human right, it is important to look at the provision of sanitation facilities holistically, and to derive scientifically-based approaches towards managing these sanitation facilities. In South Africa, the provision of adequate, appropriate, effective and sustainable sanitation facilities for all citizens is mandatory, and ventilated improved pit latrines are the minimum acceptable level of sanitation delivery in the country (DWAF, 2003). Many of the municipalities in South Africa are still struggling to reach their goal of providing basic sanitation to all, and there is an urgent need to plan and budget for a number of issues related to ventilated improved pit latrines that have been provided, before or when they become full. Management of accumulated sludge in pit latrines has become a major problem for many South African municipalities. The major problem has been on how to handle pit latrine sludge, and what disposal options are appropriate. Various disposal options have been proposed, including discharging sludge to sewer, sea outfall, wastewater treatment plant, burial onsite, transporting to landfill sites, deep row entrenchment for agroforestry and further dewatering and treatment/processing to produce agricultural fertilizers (DWAF, 2007)

Methods

Results

Discussion

Conclusion