and the Efficacy of Pit Latrine Additives - Water Research Commission

Householder questionnaire
A primary method to gain information used during the course of the research has been to investigate directly
with the users of the VIP the state of the toilet with the assistance of a questionnaire was created. All the
questions prepared had the aim to focus on the user-related issues and to be the basis from which the
results are interpreted (Table 3.4).
Table 3.4: Questions included in questionnaire administered to owners or household members of
homes with VIPs used in the study
Question
1 How many people in the household
2 How many children
3 How many are at home during the day
4 How old it is the pit
5 Was it recently emptied If so, when
6 Have any additives or chemicals been added If so, when
7 Do you in anyway adjust the pit to enhance its performance
8 Did you pour water in it, or any other kind of liquid
9 Have you experienced any particular problem with the pit (strong smells, and so on) that made
you think the pit wasn’t working well
Sampling technique
Two different categories of sample were collected; homogeneous samples and location-specific samples:
Homogeneous samples: a well mixed sample where the physical/biological characteristics are
homogenized in order to represent the pit content on general basis
Location-specific samples: a sample which maintains the in situ characteristics of the location of the pit
where it was collected from
Location-specific samples were obtained from the centre of the pit (directly below the pedestal hole) at
different heights below the surface and from the side of the pit (near the back plate) at different heights
below the surface.
Analyses
The following analyses were performed:
Total, organic and fixed solids according to Standard Methods (APHA, 1998) (Section 3.3.1.3)
Open reflux COD (Samples were suspended in distilled water to obtain appropriate dilutions for the
analysis). Results are presented on a per-dry-solids basis to eliminate variability associated with
varying moisture content (Section 3.3.1.1).
Serum bottle tests for the determination of biodegradability of COD adapted from Owen et al. (1978)
(section 3.3.1.2).
Methanogenic activity determined by the rate of methane gas evolved from samples incubated under
anaerobic conditions at 35 ºC per mass of sample (Section 3.3.1.5).
Where possible, analyses were performed with three or more replicates.
3.4.4 Results: Processes in pit latrines
The results for the two substudies are presented in separate sections. Study A contains the work by
Magagne (2006) and study B is the work of Nwaneri (in preparation).
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