ASSESSMENT OF PHYSICO-CHEMICAL AND MICROBIOLOGICAL QUALITY OF HOUSEHOLD WATER IN THE VAALHARTS IRRIGATION SCHEME, SOUTH-AFRICA.

G. O’Reilly and C.C Bezuidenhout

School of Environmental Sciences and Development, North-West University (Potchefstroom Campus), Potchefstroom 2520, . e-mail: [email protected]

Keywords: Vaalharts; Escherichia coli; total coliforms; heterotrophic plate count; fungi; yeast; Streptococci; Clostridia; Pseudomonas sp.; anaerobic bacteria; distribution plants; household water.

The study area for this study will be in the Vaalharts region in the Northern , South Africa. Vaalharts is located on the border between the - and the North West Province at the confluence of the Harts- and Vaal River and has an area of 29 181 ha (1). The Vaalharts irrigation scheme was established by the government in the 1930’s and in 2003 Vaalharts Water (Vaalharts Water Association) took over the management of the scheme (1). Water quality in the Vaalharts region decreased over the past few years and there was a need for the microbiological and physico-chemical assessment. This problem was identified through discussions with Vaalharts Water (Vaalharts Water User Association) in 2010 when the issue of the impact of deteriorating water quality on drinking water production was raised. This information will assist in the establishment of a database for the Vaalharts region containing this relevant information. The aim of this study is to assess the physico- chemical and microbiological quality of household water in the Vaalharts irrigation scheme. It will be a two year study which will be conducted during 2011-2012. The study will focus on the main residential areas in the Vaalharts region which include , , and Warrenton. Domestic water is derived from the Vaal River and this water is purified to provide drinking water to the communities in this region. Studies have shown that water purification plants in South Africa may not always produce the quality and quantity of drinking water they are designed for (2). This could be due to infrastructure as well as management challenges. Thus, more detail of the purification and distribution plants (location, history, operational dynamics, size etc.) in the Vaalharts region will also be collected and used for the interpretation of the results. Previous results of a study done in 2010 of this area showed that the average Escherichia coli numbers prior to purification were 1106 CFU/100ml and after purification 60 CFU/100ml. Even though the numbers of E. coli were reduced during the purification process, the water after purification (household water) did not comply with the South African National Standards for drinking water (SANS 241:2006), which states that the maximum allowable amount of E. coli in drinking water is 10 CFU/100ml. The average amount of total coliforms for the household water also exceeded the SANS standard of 10 CFU/100ml, having an average of 104 CFU/100ml. Even though the physico-chemical parameters that were measured complied with the SANS 241 standards, the Electrical Conductivity and salinity in raw- and drinking water were of concern in some areas of the region, because it increased from the first sample period to the second sample period. In 2011 Escherichia coli were detected in certain areas. The average Escherichia coli numbers prior to purification were 12 CFU/100ml and after purification 0 CFU/100ml. This was a very positive result, because not only did the household water comply with the SANS 241 standard, but the purification processes were successful by removing all the E. coli’s from the raw water. The total coliform numbers complied with the SANS 241 standard in most of the areas, having an average of 9 CFU/ml. Heterotrophic plate counts were alarming for the household water with great amounts of pigmented (yellow, orange, pink) and non-pigmented (white) colonies as well as fungi that grew on R2A agar which exceeded the SANS 241 standard of 5000 CFU/ml. This can be an indication of some failure in treatment processes. Streptococci were present (2 CFU/100ml) in household water of only one the areas. The average amount of Clostridia that were present in the household water was 14 CFU/100ml. In two of the areas the Pseudomonas sp. numbers were high with averages of 45 CFU/100ml and 134 CFU/100ml respectively. The average amount of fungi in household water increased from the first sampling period (1.42x104 CFU/ml) to the second sampling period (25.31x104 CFU/ml). Yeast were only present in household water of one of the areas with an average of 1x102 CFU/ml. High amounts of total anaerobic bacteria were present in the raw- and household water of one area. The physico-chemical parameters that were measured complied with the SANS 241 standards, but the Electrical Conductivity and salinity were of concern, because it increased from the first sampling period to the second sampling period. Further studies still need to be done to include analyses prior and after the raining season as well as during the warmer and colder seasons of the year. This will be conducted during 2012. The Vaalharts region is actively involved in exports and a main contributor to the economy of the Northern Cape and North West Provinces. It is thus important to investigate concerns of the water users association pertaining to water quality issues.

REFERENCES

1. VAN VUUREN, L. 2009. Water savings: persistence pays off at Vaalharts. The Water Wheel. 12-15 p. November/December. 2. MOMBA, M.N.B., TYAFA, Z., MAKALA, N., BROUCKAERT, B.M. & OBI, C.L. 2006. Safe drinking water still a dream in rural areas of South Africa. Case study: the Eastern Cape Province. Water SA, 32(5):715-720.