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This study investigated variations in the characteristics of the sludge content from different ventilated improved pit (VIP) latrines and variation in these characteristics at specific depths within each pit. Faecal sludge from 16 VIP latrines within the eThekwini Municipality was collected and laboratory characterisation including moisture content, total and volatile solids, chemical oxygen demand, and aerobic biodegradability was performed. Sludge samples were collected from 4 specific depths within each pit investigated. The laboratory characterisation performed showed that none of the VIP latrines investigated had the same sludge characteristics, and that within a pit sludge characteristics varied with increasing depth in the pit. This supports the motivating hypothesis that, depending on household habits and local environmental conditions, there should be considerable variation in the organic contents, moisture content, non-biodegradable content and microbial population between different pits. This variation with increasing depth within a pit is expected, since fresh material is constantly being added to the pit overlaying older material which might have undergone a certain degree of stabilisation.

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.Keywords: additives, digestion, pit content, sludge, public health, VIP latrine

Rainwater harvesting (RWH) is a relatively inexpensive technology that has the potential to provide safe water in communities where conventional technologies are difficult to implement. In this study, the microbiological quality of rainwater harvested from rooftops and ground-surface runoff was evaluated based on the concentrations of Escherichia coli , total coliforms and enterococci. Samples were collected from 15 roof-harvested rainwater (RHRW) tanks, 4 ground-surface runoff rainwater harvesting (GRWH) tanks, 3 rivers and 1 spring water source in the Eastern Cape Province of South Africa, and 14 RHRW tanks in Gauteng Province. In the Eastern Cape Province E. coli and enterococci were detected in 7 and 4 of the 15 RHRW tanks, respectively. Enterococci were detected only from one river whereas E. coli was detected in all three rivers; in spring water neither enterococci nor E. coli were detected. Samples from GRWH tanks were positive for E. coli and enterococci in 2 and 3 of the 4 tanks, respectively. In Gauteng Province, E. coli , coliforms and enterococci were detected from 6, 6 and 9 of the 14 rainwater tanks, respectively. On average, E. coli and enterococci were detected in 44.8% of the RHRW tanks, although enterococci concentrations were several times higher than those for E. coli . We further evaluated the significance of urban pigeons as the likely sources of contamination by isolating 156 enterococci from 30 pigeon faecal samples and 208 enterococci from RHRW samples collected from Gauteng Province. Matrix-assisted laser desorption ionisation identification of the various enterococci revealed 4 species – E. faecalis (20.5%), E. mundtii (20.51%), E. faecium (23.1%) and E. casseliflavus (17.3%) – to be dominant in faecal samples, whereas E. casseliflavus (34.6%) and E. mundtii (33.2%) were dominant in RHRW. Keywords : rainwater harvesting, contamination, indicator bacteria, health risks