Browsing by Author "Gomezulu, Edwin Sifuel"

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    Assessment of Nitrogen Nutrients removal efficiency in constructed mangrove wetlands
    (2008) Gomezulu, Edwin Sifuel
    A study was conducted to assess the efficiency of a constructed mangrove wetland in removing nitrogen nutrients from sewage. The constructed wetland was built at Kunduchi near Belinda Hotel in Dar es Salaam. The sewage from the hotel was conveyed to the site through a pipe. There were initial experiments which were conducted in bare cells which aimed at optimizing the sewage loadings which could have been used in the planted cells. No significant difference in nitrogen nutrients removal was observed between the different sewage loadings used and therefore the sewage loadings used in the planted cells were chosen just to ensure that there was sufficient difference between the dosing ratios. So the sewage dosing ratios chosen were 0, 20, 40 and 60 % compared to 10, 20 and 30 % which were used in the bare cells; Wastewater samples were analyzed for ammonia nitrogen, nitrate nitrogen and organic nitrogen. Planted cells were found to be more efficient in removing nitrogen nutrients than the non-planted cells. However the cells with Rhizophora mucronata were found to be more efficient in removing nitrogen nutrients than Avicennia marina cells. The cells that were loaded with 60 % sewage removed nitrogen nutrients than the cells which were loaded with 0 % sewage. With respect to dosing ratios, it was concluded that the higher sewage dosing ratios were more appropriate in nitrogen nutrients removal than the low sewage dosing ratios.
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    The effectiveness of environmental impact (ei) mitigation measures in protecting ground water resources in the mining areas of Tanzania: the case of Buzwagi Gold Mine
    (University of Dar es Salaam, 2016) Gomezulu, Edwin Sifuel
    This study aimed at assessing the effectiveness of Environmental Impact (EI) mitigation measures in protecting ground water resource. The study assessed the quality of ground water and availability of water for local users in villages surrounding Buzwagi gold mine project which were Mwendakulima, Mwime and Nyihogo. Water and sediment samples were collected from wells in the villages whereby 28 water samples and 22 sediment samples were collected for every three months for a period of 297 days. The samples were analyzed for electrical conductivity, pH, cyanide and some selected heavy metals. Meteorological data were collected from Tanzania Meteorological Agency (TMA). The geological and topographical maps of the area were taken from Geological Survey of Tanzania (GST). The Social data were obtained through interviews. The results showed high levels of Mn, Cr, Zn, Pb and Fe in sediments while Pb and Fe levels in water exceeded the Tanzania Bureau of Standards (TBS) limit for drinking water in some wells. In addition CN was observed in wells which are closer to the mine than those far from the mine. The net amount of water in the aquifer was predicted to be 888 m3 in the next 5 years which may not be sufficient for community demand while high CN level was predicted in the wells closest to the TSF. It was concluded that not all the mitigation measures suggested in the EIA were implemented or the impact prediction and evaluation was not correct. It was recommended that the pumping rate of water should be low during dry season, the water flow metre should be installed and that the TSF’s liner should be regularly checked to ensure zero discharge as stated in the Environmental Management Plan (EMP).Further study was also recommended with more number of samples and prolonged sampling period.