WASTEWATER HEAVY METAL STATUS IN STREAMS AND WASTEWATER
TREATMENT PLANTS OF BLANTYRE, MALAWI
S. M.I. Sajidu1, E.M.T Henry1, W.R.L. Masamba1, S.M. Kuyeli2,
1
2
Chemistry Department, Chancellor College, P.O Box 280, Zomba, Malawi.
Blantyre City Assembly Pollution Control Office, Private Bag 67, Blantyre, Malawi.
Abstract
The population of the city of Blantyre has grown rapidly over the past few years without
keeping pace with the national economy. The most visibly affected areas are access to
adequate clean water, solid waste collection and disposal, sanitary and sewerage facilities
In 1998 the city had a population of 478,155 accounting for 34.5% of the country’s total
urban population with a growth rate of 4.1% per annum. The objective of this study was
to evaluate water quality in streams and wastewater treatment plants in the city of
Blantyre, Malawi.
Water in Blantyre City Assembly streams and wastewaters at the city’s wastewater
treatment plants (WWTP) were investigated in February 2005 to determine the effect of
WWTP processes, industrial and agricultural runoffs on some physico-chemical
parameters. Study locations included Limbe WWTP, Soche WWTP, Limbe, Mudi and
Nasolo streams. Levels of lead, cadmium, iron, manganese, zinc, chromium and nickel
were much higher than the World Health safe limits for drinking water in all the sampled
streams after they had passed through industrial areas. These higher values were
attributed to uncontrolled industrial waste disposal and vehicular emissions. Nitrates and
sulphates levels at all sampling points were found to be lower than the safe limits for
drinking water of 50 mg/L and 250 mg/L respectively. However phosphate levels were
significantly above the safe limit of 0.5 mg/L. It was also observed that BOD5 levels were
significantly above the World Health Organisation limit of 20 mg/L at all sites except
Mudi and Limbe streams before passing through industrial areas. This was an indication
of pollution in the streams. Levels of pH and TDS were within the recommended
standards.
Keywords:
Blantyre, wastewater, physico-chemical parameters
THEME: Water and Environment