dc.description.abstract |
Bahir Dar city ’j surface water bodies are being influenced by different pollutions.
Unavailability of waste water treatment plants and disposal of wastewater generated
from different areas to lake Tana and Abay River are taking a big role in the
contamination. This study explores the effects of waste water on the surface water
bodies of Bahir Dar city by analyzing the characteristics of waste water. Primary and
secondary data were used to carry out the research. Seven sample stations, of which five
monitoring stations are connected to Lake Tana and two disposed to Abay River were
selected for sampling. And the samples were taken once a month, for consecutive three
months of the dry season and the wet season. The selected waste water parameters were
E-conductivity, turbidity, Total dissolved Solids, Dissolved Oxygen, Nitrate, Biological
oxygen demand
, pH, phosphate and E-coliform. The samples were analyzed triplicates to
obtain the average value. Analysis of variance– single factor was used to determine the
seasonal variation of the parameters. Statistical Package for the Social Sciences, a twoway cluster was used to identify the highly polluted disposal points. The laboratory
analysis indicated that all dissolved oxygen, Biological Oxygen Demand, and phosphate
were above the maximum limits. Whereas, Conductivity, Total dissolved solids,
turbidity, nitrate, most value pH and some E-coliform results are below the standard
limits set by Ambient Environment standards for Ethiopian and Environment Protection
Agency. The analysis of variance result indicates that all turbidity, most of the biological
oxy gen demand, and nitrate of the samples didn’t have seasonal variation. While others parameters
show significant differences at different seasons and sampling stations. SPSS results
show the highly polluted waste water originates from cluster five which is dominated by
cluster six
.
Generally, the surface water bodies are affected by the excess amount of
dissolved oxygen, biological oxygen demand and phosphate.
Key words: Bahir Dar city, wastewater, parameter, seasonal variation, surface water |
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