and the Efficacy of Pit Latrine Additives - Water Research Commission

To test samples of a commercially available pit additive and corresponding placebos by recording their
effect over a period of two weeks
To familiarise the researchers, through first hand experience, with various factors important to an
understanding of filling rates and pit latrine sanitation management in general
To enable the researchers to plan relevant and effective future studies aimed at investigating pit latrine
sanitation problems and challenges
4.3.2 Methodology
The study was conducted in Mpumuza, a peri-urban but rural area northwest of Pietermaritzburg. A total of 9
pits were monitored. Four latrines belonging to private residences and four scholars' pit latrines at a primary
school were visited, described and tested. One of the privately owned facilities comprised a double latrine
with two separate pits and pedestals, both currently in use. The four school latrines were selected from a
total of 19 latrines.
The nine pits were visited between 9 and 11 am on three occasions, one week apart, on 27/2/07, 6/3/07 and
13/3/07. During the initial visit, owners, users or occupants were questioned to establish the age of the
latrine, number of users, on-site alternatives and any intermittent or routine management practices (adding of
Jeye's fluid, dip, ash, or other).
The latrine design and the appearance of the structure and the contents of the pit were described and
recorded. The contents of the pit viewed through the seat and the external structure were photographed. The
coordinates of each site were recorded using a hand held Garman GPS.
Using a graduated, weighted string, the distance from the underside of seat to the highest point of the heap
was measured at each visit while the height of the pedestal (from the underside of seat to the underside of
slab) was recorded at the first visit. In addition the height of the heap in relation to the lowest point in the pit
(at the back wall) was estimated by eye
Table 4.2: Random allocation of additives and placebos in study pits, weeks 1 to 3
Pit Latrine Week 1 (27/2/07) Week 2 (6/3/07) Week 3 (13/3/07)
1 A 1 P 1 P 1
2 P 1 A 1 P 1
3 P 2 A 1 P 1
4 A 2 P 1 P 1
5 P 1 P 1 P 1
6 P 1 A 1 P 1
7 A 2 A 1 P 1
8 P 2 P 1 P 1
9 A 1 A 1 P 1
A 1 = White, powdery pit additive (7 samples; 2 administered week 1 and 5 week 2)
A 2 = Coarse, brown pit additive (2 samples; administered in week 1)
P 1 = White CMC placebo (3 added week 1, 4 week 2 and 9 week 3)
P 2 = Layer mash placebo (2 added week 1)
The manufacturer said that the two samples tested contained the same “active ingredient” but were mixed
with two different bulking agents. One set of samples (7) contained a uniform white powder (according to the
manufacturer this was calcium carbonate to “enhance oxygen necessary for activation of bacteria”) and the
second (2 samples) was a coarser, less dense brown mixture resembling chicken food mash (described as a
bran carrier). Total number of samples was 9.
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