Assesement of the quality of leachate at Sarbah landfill site at Weija in Accra

Abstract

Physico-chemical and bacteriological characteristics of Sarbah dump site at Weija, Accra were investigated to ascertain the leachate quality for possible treatment. The leachate was observed to be alkaline in nature and had high concentration of the following biological oxygen demand (BOD), chemical oxygen damand (COD) and oil and grease. Samples of leachate were collected from different sites close to the landfill. On average the leachate contained high turbidity (840 NTU), colour (4,000 Hz), suspended solids (493 mg/l) and total dissolved solids (16725 mg/l), but no dissolved oxygen. Heavy metal such as Cd, Zn, Pb, Mn, Cr, Hg and Cu and their contamination were within the Environmental Protection Agency of Ghana (EPA) guideline limits except Fe which was relatively high. The study showed the possibility of leachate contamination of nearby water body. The leachate was found to be contaminated with microorganisms and some of which have public health implications. The major pathogens isolated in the leachates from Sarbah dump site were total coliform (TC), faecal coliforms (FC), Escherichia coli, Salmonella spps, Vibrospp, Bacillus spp, Yeast and Moulds. TC and FC were predominant in all the sites and their levels were above the EPA permissible limits. The highest levels were recorded at site I,TC (26 x10⁶ CFU/ 100 ml); FC (33 x 10⁵ CFU/ 100 ml) ] and the lowest observed at site IV,TC (18.6 x 10² CFU/ 100 ml)] ; (FC (38.4 x 10 CFU/ 100ml).Specific bacteria pathogens, E. coli (22.4 x 10⁵ CFU/100 ml), Salmonella (41 x 10³ CFU/100 ml), Vibrospp (12 x 10 CFU/100 ml) were present at site I but absent at site II. The dominant biological pollutants in the leachate could expose the residence around the dump site to the risk of the following diseases; malaria, intestinal worms, upper respiratory infections, typhoid fever, dysentery, salmonellosis, cholera and gastroenteritis.