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Common Property Resource Management, Institutional Change and Conflicts in African Floodplain Wetlands
Haller, Tobias
Most contemporary discussions on African development since independence forty years ago emphasize the notion that Africa is still “mal parti”. Many show discontent for what has been achieved in this time, despite that “Africa works” as is suggested by Chabal and Daloz in their widely discussed book (1999). I will focus on the issue of sustainable development in Africa. This will be illustrated by the presentation of a common property resource management research project (on fisheries, pastures, wildlife, water for irrigation, and forests). The question of why the overuse of natural resources and conflicts over resources are occurring in modern day Africa is addressed here. This research project is called “Common Property Institutions and Power Relations: Resource Management, Change and Conflicts in African Floodplain Wetlands”. It focuses on six African floodplain wetlands in semi-arid zones (Internal Niger Delta in Mali, Hadejia-Jama'ara in Northern Nigeria, Logone Floodplain in Northern Cameroon, Pangani Floodplain in Tanzania, Okavango Delta in Botswana and Kafue Flats in Zambia (Haller 2001)) [...]. The African Anthropologist 2002, Vol 9, No.1, pp. 25-35 Available from: African Journals Online
Reuse and Recycle of Bio-residue (percolate) from Constructed Wetland Treating Septage
Hadsoi, Sukon
Master's Thesis, Asian Institute of Technology, Thailand "The prime objective of this research is to investigate the suitability of percolate from constructed wetland (CW) treating septage in agricultural application with the specific focus on determination of appropriate application ratio of percolate on sunflower plantation and crop yields." Download
Treatment of septage in constructed wetlands in tropical climate
Koottatep, Thammarat
In tropical regions, where most of the developing countries are located, septic tanks and other onsite sanitation systems are the predominant form of storage and pre-treatment of excreta and wastewater, generating septage and other types of sludges. The septage is disposed of untreated, mainly due to lack of affordable treatment options. This study presents lessons that have been learned from the operation of pilot-scale constructed wetlands (CWs) for septage treatment since 1997. The experiments have been conducted by using three CW units planted with narrow-leave cattails (Typha augustifolia) and operating in a vertical-flow mode. Based on the experimental results, it can be suggested that the optimum solids loading rate be 250 kg TS/m2 yr and 6-day percolate impoundment. At these operational conditions, the removal efficiencies of CW units treating septage at the range of 80–96% for COD, TS and TKN were achieved. The biosolid accumulated on the CW units to a depth of 80 cm has never been removed during 7 years of operation, but bed permeability remained unimpaired. The biosolid contains viable helminth eggs below critical limit of sludge quality standards for agricultural use. Subject to local conditions, the suggested operational criteria should be reassessed at the full-scale implementation. Keywords Nutrient removal; operation; helminth eggs; septage treatment; vertical-flow constructed wetlands Water Science and Technology 2005, Vol. 51, No. 9, pp. 119–126 Available for purchase from: IWA Publishing
Potentials of vertical flow constructed wetlands for faecal sludge dewatering in Subsaharian countries
Kengne Noumsi, Ives Magloire
PhD Thesis, University of Yaoundé, Cameroon For further information please contact the author
Integrated faecal sludge treatment and recycling through constructed wetlands and sunflower plant irrigation
Koottatep, Thammarat
"Faecal sludge (FS) from the on-site sanitation systems is a nutrient-rich source but can contain high concentrations of toxic metals and chemicals and infectious micro-organisms. The study employed 3 vertical-flow CW units, each with a dimension of 5×5×0.65 m (width×length×media depth) and planted with cattails (Typha augustifolia). At the solid loading rate of 250 kg total solids (TS)/m2.yr and a 6-day percolate impoundment, the CW system could achieve chemical oxygen demand (COD), TS and total Kjeldahl nitrogen (TKN) removal efficiencies in the range of 80–96%. A solid layer of about 80 cm was found accumulated on the CW bed surface after operating the CW units for 7 years, but no clogging problem has been observed. The CW percolate was applied to 16 irrigation sunflower plant (Helianthus annuus) plots, each with a dimension of 4.5×4.5 m (width×length). In the study, tap water was mixed with 20%, 80% and 100% of the CW percolate at the application rate of 7.5 mm/day. Based on a 1-year data in which 3 crops of plantation were experimented, the contents of Zn, Mn and Cu in soil of the experimental plots were found to increase with increase in CW percolate ratios. In a plot with 100% of CW percolate irrigation, the maximum Zn, Mn and Cu concentrations of 5.0, 12.3 and 2.5 mg/kg, respectively, were detected in the percolate-fed soil, whereas no accumulation of heavy metals in the plant tissues (i.e. leaves, stems and flowers) of the sunflower were detected. The highest plant biomass yield and oil content of 1000 kg/ha and 35%, respectively, were obtained from the plots fed with 20% or 50% of the CW percolate." Water Science and Technology 2006, Vol. 54, No. 11-12, pp. 155–164 Available from: IWA Publishing