Pit emptying systems
Practical Action
Table 2: Advantages and Disadvantages of Manual Emptying
Advantages
Disadvantages
Services accessible to community
High unit cost of removal
Relatively cheap to keep latrine operational Significant health risks to workers
Low equipment capital cost
Rarely acceptable to municipalities and so
not regulated
Associated with indiscriminate dumping
Lack of appropriate equipment means
spillage regularly occurs
Will often require the slab of the latrine to be
demolished to facilitate access, subsequently
increasing householder cost
Manually Driven Mechanical Systems
The main technology type in this category is called the Manual Pit Emptying Technology
(MAPET), it was developed in the early 1990s and came at a cost of US$3,000. The machine
brought some successes but ultimately failed due to a reliance on imported spare parts and a
lack of institutional support. Therefore it will not be discussed in further detail because it is
unavailable for use.
A relatively new technology type in this category is the London School of Hygiene and Tropical
Medicine (LSHTM) Sludge Gulper. This is a hand pump that can be lowered into a pit or tank
and used to lift the contents out into a bucket. The system is currently still being trialled on
varying types of sludge. Whether it performs successfully in all locations is yet to be seen.
There are two critical features of the sludge gulper which make it advantageous. Firstly it has
been constructed entirely from local materials in Indonesia and Cambodia; one factor that
brought about the downfall of the MAPET. Secondly the cost of the system is very low, costing
only US$40 to build in Indonesia.
The two biggest potential problems are the non-odourless nature of the technology and the
requirement for the further containerisation of the sludge.
Table 3: Advantages and Disadvantages of the LSHTM sludge gulper
Advantages
Disadvantages
Low cost when compared to other
Requirement for further containerisation and
technologies, so suitable for small scale
safe disposal of waste
independent providers (SSIPs)
Possible to produce locally in many areas
Could still produce unpleasant odours
Facilitates access into even very densely
May be difficult to operate on thick sludge or
populated areas
low volume installation
Low operation and maintenance costs
Specifically Designed Mechanical Systems
During the 1990s there have been a series of machines designed specifically for densely
populated urban areas where access poses a problem. The most accessible of these
technologies is the UN-HABITAT/Manus Coffey and Associates Ltd developed Vacutug
machine (figure 3). Other technologies have been used, but they are less directly available;
they include (i) the Manquineta (WaterAid/MSF machine) used in Mozambique, and (ii)
Vacutug Mk II (figure 4), trialled in Dhaka, Bangladesh.
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