Illustrated training booklet with step-by-step instructions for teams emptying onsite urine diverting dry toilet vaults. The principles can also be applied to emptying of other onsite sanitation systems (e.g. VIP toilets). Booklet created in collaboration with Khanyisa Projects, eThekwini Municipality, WRC, and the Bill & Melinda Gates Foundation.
This study investigated the application of the deep row entrenchment method under South African
conditions with the aim of establishing whether the use of pit latrine and wastewater sludges as a
fertilizer substitute for the agro-forestry sector can be recommended and thereby also establishing a
safe and beneficial technique for the disposal of faecal and wastewater sludges.
The development of the deep row entrenchment method in the 1970s and subsequent studies were
reviewed as were the South African guidelines for the utilisation of wastewater sludge. No guidelines
currently exist for the classification or utilisation of pit latrine sludge. Pit latrine sludge was buried at
different loading rates on a sandy site at a disused oxidation pond in Umlazi, south of Durban, and
wastewater sludge from the Howick Wastewater Treatment Works was entrenched at a Sappi
research site near Howick. The sites were characterised and monitored over time in order to
document the movement of nutrients out of the trenches and changes in groundwater over time.
The HYDRUS-2D was used to model the movement of soil-water, phosphorus and nitrate. The fate of
pathogens over time was also investigated. Tree growth was monitored in order to document
differences in growth rates between trees provided with different loading rates of sludge and
control groups. Two smaller studies were also conducted to investigate the impact of sludge on tree
growth under controlled conditions and the application of deep row entrenchment for on-site sludge
disposal.
The goal of Water Research Commission project K5/1745 was to investigate existing management
practices with regard to VIP toilets, identify challenges and lacks and develop strategies and tools for
more effective management. Existing literature and current practice was explored to consolidate
knowledge on pit filling, strategies and methodologies for pit emptying and the economic aspects of
successful on-site sanitation management. New technologies and methods were developed for pit
emptying and sustainable alternatives for the beneficial use of sludge were explored. The findings of
this research have been published in three volumes as the series Tackling the challenges of full pits. This
volume is followed by:
• Volume 2: How fast do pit toilets fill up? A scientific understanding of sludge build up and
accumulation in pit latrines
• Volume 3: The development of pit emptying technologies
This report is the second volume in the series Tackling the challenges of full pit latrines
which addresses this issue. The other volumes in the series are:
• Volume 1: Understanding sludge accumulation in VIPs and strategies for emptying full pits
• Volume 3: The development of pit emptying technologies
Current research indicates that many of the VIP systems delivered by the South African government
over the past decade can be expected to reach capacity in the very near future. Many municipalities
have not yet put the necessary strategies, policies and budgets in place to maintain these on-site
systems and are unable to predict how often they will need to be serviced. If municipalities are taken
by surprise when pits reach capacity and do not have the necessary budget, manpower and equipment
in place to respond, households will effectively find themselves without sanitation, a situation which
compromises both public health and dignity, the driving forces behind South Africa’s commitment to
basic sanitation for all.
This report presents the design, development and testing of a number of prototypes of portable pit
emptying technologies that were developed as part of Water Research Commission research project
K5/1745. It is preceded by two other reports in the Tackling the challenges of full pits series:
Volume 1: Understanding sludge accumulation in VIPs and strategies for emptying full pits
Volume 2: How fast do pit toilets fill up? A scientific understanding of sludge build up and
accumulation in pit latrines
The designs which have been explored to date have been the pit screw auger, which uses a
motorised soil auger to lift sludge from a pit, the Nano Vac and e Vac, which use piston pumps and
vane pumps to suck relatively wet sludge from pits. In addition, a pressure vessel has been
developed which can be used for collecting sludge or for pumping water or air into a pit to aid
removal.
Being portable by two people these technologies do overcome the issue of access and have proven
viable when trialled on pig slurry. The eVac has in addition been used successfully to empty wettish
pit latrines in the field, which it does with little difficulty. Being the most robust and the most
compact of the devices, the eVac appears to have the most potential on pit latrines in the field, and
should be the focus for further research and development work.
Presentation of the mass balance and accumulation of sludge in pit latrines and septic tanks.
A presentation about the science of Sludge decomposition.
Presentation about work of developing pit emptying devices, carried out by PID and Engineers Without Borders.
Local government has not yet developed an effective response to the problem of management of pit latrine waste. Practical and economical solutions must be found. This paper describes an appropriate range of options.