African Journal of Water Conservation and Sustainability

African Journal of Water Conservation and Sustainability ISSN: 2375-0936 Vol. 3 (3), pp. 138-143, March, 2015. © International Scholars Journals

Review

Making a case for systems thinking approach to integrated water resources management (IWRM)

Bloodless Dzwairo*, Fred A. O. Otieno and George M. Ochieng

Tshwane University of Technology, Faculty of Engineering and the Built Environment, Civil Engineering

Department, Private Bag X680, Pretoria, 0001, South Africa.

*Corresponding author. E-mail: [email protected], [email protected], [email protected]. Tel: 00-27-734406288. Fax: 0866010893.

Accepted 22 April, 2010

Abstract

While definite benefits could be gained from integrating the management of natural and human systems, taking into account the effects of human activities on the environment, the task of operationalising and implementing this approach in practice represents an enormous challenge. Some limitations highlighted include the definition of IWRM itself, where it appears to be broad, all-encompassing and impressive, but contains ‘‘lofty phrases’’ that have little practical importance for either present or future water management practices. This paper makes recommendations to uptake and incorporate the systems thinking approach (STA) in IWRM decision making processes, an approach envisaged to be more participatory and also process-oriented. Incorporation of socio-economic dynamics is also recommended, with a suggestion that the biophysical relationships like interactions in a basin between water, the human population and settlements should be analysed to the extent possible.

Key words: Operationalising IWRM, socio-economic dynamics, South Africa, systems thinking approach.

African Journal of Water Conservation and Sustainability ISSN: 2375-0936 Vol. 2 (3), pp. 118-125, March, 2014. © International Scholars Journals

Full Length Research Paper

Modeling hydropower plant system to improve its reservoir operation

T. G. Bosona* and G. Gebresenbet

Department of Energy and Technology, Swedish University of Agricultural Sciences, Box 7032, 750 07 Uppsala, Sweden.

*Corresponding author. E-mail: [email protected], [email protected].

Accepted 3 February, 2010

Abstract

One way of improving water management is increasing the efficiency of utilization of dam reservoirs. Even small improvement in reservoir operation can lead to large benefits. But there is no universal solution for reservoir operation problems. Hence, it is necessary to study the system and determine optimal reservoir operation guides for each scheme. In the present study, Melka Wakana Hydropower Plant in Ethiopia has been modeled and studied. The tool used was Powersim Simulation software. Mean monthly data of reservoir inflow, evaporation rate, recorded energy production; recorded discharge (turbine flow) and recorded reservoir elevation were used as time series input data. Different variables and relationships between variables were defined along with the constraints. After developing and calibrating the model successfully, detailed simulation analysis has been carried out by controlling reservoir releases for energy production, taking into consideration; increasing yearly energy production and improving the uniformity of monthly energy production. The results of the simulation analyses indicated that the yearly energy production was increased by 5.67% while evaporation loss was reduced by 38.33%. But this power plant still produces below its design capacity by 12.21%.The uniformity of monthly energy production from this plant was also improved. The new reservoir operation guide curve has been developed for the optimum energy production from this plant.

Key words: Guide curve, simulation model, reservoir operation, hydropower, energy production, water resources management.

African Journal of Water Conservation and Sustainability ISSN: 2375-0936 Vol. 2 (1), pp. 099-107, January, 2014. © International Scholars Journals

Full Length Research Paper

A study of the kinetic coefficients and the rate of biodegradation of phenol by indigenous mixed microbial system

Sudipta Dey*and Somnath Mukherjee

Department of Biotechnology, Heritage Institute of Technology, Anandapur, Chowbaga Road, PO: Kolkata, PIN:

700107, West Bengal, India.

*Corresponding author. E-mail: sudiptadey_ [email protected]. Tel: +91 33-2443-0454 or +91 9830590415. Fax: +91 033-2443-0455.

Accepted 03 July, 2010

Abstract

Mixed microbial culture collected from effluent treatment plant of a coke oven industry has been studied for its phenol biodegrading potential under aerobic condition in a batch reactor. The result showed that, after acclimatization, the culture could biodegrade up to 700 mg/l of phenol. The results showed that specific growth rate of microorganisms and specific substrate degradation rate increased up to 300 mg/l of initial phenol concentration and then started decreasing. The biodegradation kinetics is fitted to different substrate inhibition models by MATLAB 7.1^©. Among all models, Haldane model was best fitted (Root Mean Square Error = 0.0067) for phenol degradation. The different biodegradation constants (K_s, K_i, S _m, m_max, Y_X/S, k_d) estimated using these models showed good potential of the mixed microbial culture in phenol biodegradation.

Key words: Mixed culture, phenol biodegradation, kinetics, inhibition model.

African Journal of Water Conservation and Sustainability ISSN: 2375-0936 Vol. 2 (2), pp. 108-117, February, 2014. © International Scholars Journals

Full Length Research Paper

Cadmium sorption by Moringa stenopetala and Moringa oleifera seed powders: Batch, time, temperature, pH and adsorption isotherm studies

L. M. Mataka, S. M. I. Sajidu*, W. R. L. Masamba and J. F. Mwatseteza

Chemistry Department, Chancellor College, University of Malawi, P. O. Box 280, Zomba, Malawi.

*Corresponding author. E-mail: [email protected]. Tel: +265 1 524 222.

There is a widespread recognition that the presence of heavy metals such as cadmium in water is hazardous to the environment and human health and their discharge into surface waters is of great concern worldwide. The use of natural coagulants such as Moringa for heavy metal removal from water replacing expensive imported synthetic coagulants is particularly appropriate for agro-based developing countries such as Malawi. This study was aimed at investigating the potential of Moringa stenopetala and Moringa oleifera in the removal of cadmium(II) ions from water. The potential of M. stenopetala for cadmium removal was investigated by means of jar test beakers. With an initial cadmium concentration of 7 mg/l, M. stenopetala seed powder, at a dose of 2.50 g/100 ml, reduced the concentration of cadmium by 53.8%. Comparison of removal capacities between M. stenopetala and M. oleifera indicated that M. stenopetala was more effective than M. oleifera in removing cadmium from water (p < 0.05). Increasing initial cadmium concentration, agitation time and ionic strength reduced cadmium removal. Equilibrium sorption was attained at pH 5 where maximum cadmium removals were 82.7 and 70.7% using M. stenopetala and M. oleifera respectively. There was a reduction in cadmium removal between 0 to 60°C for M. stenopetala and 0 - 40°C for M. oleifera before increasing with subsequent temperature increases. It was also shown that cadmium sorption at 30°C and pH 3 for the M. oleifera could best be modelled by the Freundlich isotherm whereas the Langmuir model is slightly better than the Freundlich isotherm in the case of the M. Stenopetala. The energies of adsorption from Dubinin-Radushkevich models have indicated that cadmium removal using both powders is based on physisorption. The results indicate that M. stenopetala and M. oleifera have potential in cadmium remediation of polluted waters.

Key words: Cadmium, Moringa oleifera, Moringa stenopetala, water pollution, remediation, Freundlich, Langmuir, Dubini-Radushkevich isotherms.

African Journal of Water Conservation and Sustainability Vol. 1 (5), pp. 071-080, December, 2013. © International Scholars Journals 

Full Length Research Paper

Farmers’ perception of the effects of soil and water conservation structures on crop production: The case of Bokole watershed, Southern Ethiopia

Kebede Wolka¹*, Awdenegest Moges² and Fantaw Yimer¹

¹Wondo Genet College of Forestry and Natural Resources, Hawassa University, P.O. Box 128, Shashemene, Ethiopia.

²Biosystems and Environmental Engineering Department, Hawassa University, P.O box 5, Hawassa, Ethiopia.

*Corresponding author. E-mail: [email protected]. Tel: +251-(0) 46-1109929 or +251-(0)912-072608. Fax: +251 461191499.

Accepted 30 September, 2013

Abstract

Level soil bunds (LSB) and stone bunds (SB) have been widely implemented in Bokole watershed with World Food Programme (WFP) support since 2000-2001. However, the performance of structures against the target has not been studied. This study assessed farmers’ opinion on the effect of soil and water conservation (SWC) structures, particularly level soil bunds and stone bunds, in improving agricultural crop production. A household survey was carried out by stratified random sampling. Twenty-seven percent of the farmers who adopted SWC structure (29 households from the upper watershed and 62 households from the lower watershed) were randomly selected and interviewed. Three group discussions were also conducted. Based on their own indicators, a high proportion of those interviewed (79.3% in the upper and 87.1% in the lower watershed) had a positive opinion about LSB and SB on their cropland, in relation to its role in improving soil fertility and crop production. Ninety-three percent of interviewed farmers in both the upper watershed and the lower watershed perceived a change in crop yield within two years after implementation of structures. There is a need for awareness creation and for monitoring the correct management of existing soil and water conservation structures, to ensure that they function as intended, and to improve their efficiency. This can reduce the problem of a ‘decrease’ or ‘fluctuation’ in crop yield.

Key words: Crop yield, non-terraced, soil bunds, stone bund, water erosion.