Browsing by Author "Mukandala, Renalda"

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    Performance of horizontal subsurface flow constructed wetland (HSSFCW) in the treatment of TANNIS wastewater
    (University of Dar es Salaam, 2006) Mukandala, Renalda
    The performance of a Horizontal Subsurface Flow Constructed Wetland (HSSFCW) system in the treatment of tannins wastewater (TWW) was studied. Two HSSFCW cells one planted with Phragmites mauritianus and the other unplanted were used. In order to increase the possibility of biodegradation of tannins in the HSSFCW, seeding was necessary . Primary facultative pond sludge was found to perform better than the rumen fluid, thus the former was used in th is study. Two experiments were done. In the first run 1g/l tannin wastewater made from spray-dried mimosa extract was mixed with primary facultative pond wastewater (FPWW), and the resultant tannins wastewater was passed through the HSSFCW. In the second run, the pre-treated tannins wastewater from the Three Phase Fluidised Bed bioreactor (TPFBB) was used. The results obtained indicated that HSSFCW was capable of treating tannins wastewater. Tannins and COD removal efficiency of 95.9% and 90.6% with outlet concentration of 27mg/l and 86mg/l, respectively was obtained in the planted cell for pre-treated TWW; while the tannins and COD removal efficiency of 91.1% and 89.5% with outlet concentration of 57mg/L and 96rng/L, respectively was obtained in the control cell. For pre-treated TWW, the tannins and COD removal efficiency of 92.9% and 91.3% with outlet concentration of 50mg/l and 90mg/1, respectively was obtained in the planted cell. Results from the model indicated that biodegradation was the dominant process of tannins removal in the HSSFCW. The model results also indicated that the developed model was able to simulate the tannins removal processes in the CW and thus can be used to predict the removal efficiency of tannins in the HSSFCW.