| 1. |
- Bojcevska, Hristina, 1977-, et al.
(författare)
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Free water surface constructed wetlands for polishing sugar factory effluent in western Kenya : macrophyte phosphorus recovery and treatment results
- 2006
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Ingår i: Proceedings of the 10th International Conference on Wetland Systems for Water Pollution Control, 23-29 September 2006. - Lisbon : Ministério de Ambiente, do Ordenamento do Territóri e do Desenvolvimento Regional (MAOTDR) and IWA. ; , s. 709-718
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Konferensbidrag (refereegranskat)abstract
- Wastewater treatment and nitrogen and phosphorus (P) recovery in harvested biomass of two macrophyte species receiving two wastewater loading rates was studied in a free water surface constructed wetland (FWS CW) in Kenya. Half the CWs were planted with Cyperus papyrus and half with Echinochloa pyramidalis. Inlets and outlets water samples were analysed for selected water quality parameters. Macrophytes were harvested at around 7 month intervals on three occasions for determination of biomass, P and N content. Area specific removals of TP, TSS and Nh4+-N were higher in the high-load CWs and in the low-load ones, but the relative removal was lower. For Nh4+-N, there was a significantly higher removal in C. papyrus CWs- Each macrophyte species had similar tissue P content independent of mass load suggesting excess available phosphorus in all CWs, as supported by the low N:P ratios. During a 7 month period, the amount of P stored daily in the green biomass of the macrophytes represented 18-29% and 25-100% of the daily removal of TP and TDP, respectively.
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| 2. |
- Bodin, Hristina, et al.
(författare)
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Free water surface constructed wetlands for polishing sugar factory effluent in western Kenya : macrophyte phosphorus recovery and treatment results
- 2006
-
Ingår i: Proceedings of the 10th International Conference on Wetland Systems for Water Pollution Control, 23-29 September 2006. ; , s. 709-718
-
Konferensbidrag (refereegranskat)abstract
- Wastewater treatment and nitrogen and phosphorus (P) recovery in harvested biomass of two macrophyte species receiving two wastewater loading rates was studied in a free water surface constructed wetland (FWS CW) in Kenya. Half the CWs were planted with Cyperus papyrus and half with Echinochloa pyramidalis. Inlets and outlets water samples were analysed for selected water quality parameters. Macrophytes were harvested at around 7 month intervals on three occasions for determination of biomass, P and N content. Area specific removals of TP, TSS and Nh4+-N were higher in the high-load CWs and in the low-load ones, but the relative removal was lower. For Nh4+-N, there was a significantly higher removal in C. papyrus CWs- Each macrophyte species had similar tissue P content independent of mass load suggesting excess available phosphorus in all CWs, as supported by the low N:P ratios. During a 7 month period, the amount of P stored daily in the green biomass of the macrophytes represented 18-29% and 25-100% of the daily removal of TP and TDP, respectively.
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| 3. |
- Grönlund, Erik, 1964-, et al.
(författare)
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Emergy Assessment of a Wastewater Treatment Pond System in the Lake Victoria Basin
- 2017
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Ingår i: Journal of Environmental Accounting and Management. - Carbon, United States : L & H Scientific Publishing, LLC. - 2325-6192 .- 2325-6206. ; 5:1, s. 11-26
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Tidskriftsartikel (refereegranskat)abstract
- As part of efforts to reduce the eutrophying load to Lake Victoria, a wastewater treatment system at one of the sugar factories in Kenya was evaluated with the ecosystem ecology method emergy accounting. As a comparison a traditional cost analysis was also performed. The analysis included the local and imported ecosystem services. After preliminary treatment the effluent was discharged into a series of 12 stabilisation ponds. The removal of COD and TSS was high, whereas phosphorus concentrations were reduced by less than 20 %. The monetary costs were dominated by operation and management cost, some of which could probably be reduced by more effective management. The local ecosystem services in emergy terms contributed only 1% (or 1,000 Em$) to the treatment system. Imported ecosystem services in purchased lime contributed more to the treatment system, 22% (or 24,600 Em$). Since the land costs in the area were low, land demanding treatment methods using free local ecosystem services, could be cost effective choices for wastewater management. Ecosystem ecology methods as emergy accountings can guide these choices by revealing the additional contribution of free ecosystem services. Emergy accountings seem to need further clarification regarding differences in micro-/macroeconomic views.
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