Fasil Ejigu Eregno, Chong‐Yu Xu and Nils‐Otto Kitterød
Recent advances in hydrological impact studies point that the response of specific catchments to climate change scenario using a single model approach is questionable. This study…
Abstract
Purpose
Recent advances in hydrological impact studies point that the response of specific catchments to climate change scenario using a single model approach is questionable. This study was aimed at investigating the impact of climate change on three river basins in China, Ethiopia and Norway using WASMOD and HBV hydrological models.
Design/methodology/approach
First, hydrological models' parameters were determined using current hydro‐climatic data inputs. Second, the historical time series of climatic data was adjusted according to the climate change scenarios. Third, the hydrological characteristics of the catchments under the adjusted climatic conditions were simulated using the calibrated hydrological models. Finally, comparisons of the model simulations of the current and possible future hydrological characteristics were performed. Responses were evaluated in terms of runoff, actual evapotranspiration and soil moisture change for incremental precipitation and temperature change scenarios.
Findings
From the results obtained, it can be inferred that two equally well calibrated models gave different hydrological response to hypothetical climatic scenarios. The authors' findings support the concern that climate change analysis using lumped hydrological models may lead to unreliable conclusions.
Practical implications
Extrapolation of driving forces (temperature and precipitation) beyond the range of parameter calibration yields unreliable response. It is beyond the scope of this study to reduce this model ambiguity, but reduction of uncertainty is a challenge for further research.
Originality/value
The research was conducted based on the primary time series data using the existing two hydrological models to test the magnitude differences one can expect when using different hydrological models to simulate hydrological response of climate changes in different climate zones.
Details
Keywords
Melesse Eshetu Moges, Fasil Ejigu Eregno and Arve Heistad
The purpose of this paper is to investigate the performance of biochar and fine filtralite as a polishing filter material in further removing organic matter, phosphorous…
Abstract
Purpose
The purpose of this paper is to investigate the performance of biochar and fine filtralite as a polishing filter material in further removing organic matter, phosphorous, nitrogen, turbidity and indicator microorganisms from effluents of a compact greywater treatment plant (GWTP).
Design/methodology/approach
A filtration experiment was carried out using columns filled with biochar and fine filtralite as filter material and unfilled column as a control. The effluent from the GWTP was pumped using a peristaltic pump at a rate of 280 l/m2-d and was fed in upward flow into the columns. The quality parameters of the raw greywater, effluents from the GWTP and the polishing columns were studied for six months of operation period.
Findings
The results indicate that the process of polishing considerably improved the effluent quality of the system. Biochar performed best in removing organic matter, total N, turbidity and odor. Filtralite was superior in removing P. The contribution of the polishing step in removing total coliform bacteria (TCB) and Escherichia coli (E. coli) was remarkable. Additional log reduction of 2.18, 2.26 and 1.81 for TCB and 2.26, 2.70 and 2.01 for E. coli was obtained compared to the GWTP due to biochar, filtralite and control column, respectively.
Practical implications
This study demonstrates the opportunities for improving the performance of decentralized greywater treatment systems by integrating locally available polishing materials to achieve a better quality effluent.
Originality/value
The present study identifies efficient polishing system for decentralized and compacted greywater treatment system. The recommended polishing materials potentially improve the quality of effluents and add social, economic and environmental values.