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|Title: ||Groundwater pollution from on-site sanitation|
|Authors: ||Dugbartey, Divine Dornu|
|Issue Date: ||26-Jan-2001|
|Series/Report no.: ||3025;|
|Abstract: ||There is growing concern that widespread use of on-site sanitation system will cause subsurface migration of contamination ultimately resulting in disease transmission and environmental degradation. This study assessed the pollution levels of contaminants associated with on-site sanitation in forty-five groundwater supplies, in the Sekyere East District of Ashanti Region of Ghana. These groundwater supplies, comprising 26 hands dug wells and 19 boreholes, were constructed under the National Community Water and Sanitation Programme to improve the water supply situation in rural areas.
Out of the 45-groundwater supplies sampled, 7 hand-dug wells were polluted with faecal coliforni wioso and Oyoko Mission hand dug wells recorded faecal coliform counts of 190 cfu/100ml and 150 cuf/100ml respectively.
Analysis of information from the field and records showed that two of these facilities were being polluted by pit latrines, which can he described as wet pits.
The third hand dug well, which recorded a faecal coliform of 57 cfu/100ml was suspected of’ being polluted through a hydraulic connection with a stream 14m away from the well. Odurokrom. Bimma No. 2. Adagva No.1 and Abotanso recorded faecal coliform counts of 5 cfu/ 100ml: 6 cfu/100ml: 8 cfu/ 100ml: and 10 cfu/ 100ml respectively These were suspected of being polluted from the surface through water draining under the loose hand pump stand into the well All the values exceeded the WHO guidelines value for faecal coliform, which is 0 cfu/ml. Wioso and Oyoko Mission recorded the highest value of other key faecal contamination indicator such as nitrate and chloride. The nitrate values recorded were 39.9mg/l and 32.4mgl respectively. Chloride values were 20.5mg/l and 18.5mg/I for wioso and Oyoko Mission respectively. These values were within WHO Guideline values for nitrate and chloride, which are 45 mg/l and 250 mg/l respectively.
The soil analysis showed that samples from the district were well graded with varying amounts of clay. The percolation rates in the various soil profiles were of the order 10-5ms. These rates can be described as medium rates, and with proper siting of groundwater supplies should be able to protect groundwater 1mm pollution from on—site sanitation s stems.
Siting of groundwater supplies should not be based on a rule of thumb hut rather on—site specific hydrogeological conditions. On-site sanitation technology choice should also be based on hvdrogeological conditions and modifications made where necessary.
The community Water and Sanitation Agency and other providers of groundwater supplies should collaborate with the District Assemblies to carry out groundwater quality monitoring programmes.
This would ensure an extensive evaluation of’ the relationship between groundwater supplies and on—site sanitation systems. so that remedial action can be taken as appropriate.|
|Description: ||A Thesis submitted to the Board of Postgraduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi in partial fulfilment of the requirements for the award of the Degree of Master of Science in Water Supply and Environmental Sanitation, 2001|
|Appears in Collections:||College of Engineering|
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