Volume 19 [2017]

Herein, we describe the batch and fixed-bed column adsorption of Cu2+ and Pb2+ by raw and treated date palm leaves (DP) and orange peel (OP) waste biomass. Contact time, pH, adsorbent dose, and particle size were optimized in batch adsorption experiments, while breakthrough curves obtained in fixed-bed adsorption experiments were used to determine the effects of bed height, initial metal concentration, particle size, and flow rate. The use of treated DP and/or OP in batch adsorption mode increased the removal efficiency of metal ions by 20–30% compared to that observed for raw adsorbents. The equilibration time was estimated as 0.5 h, with rapid metal removal observed during the first 15 min at an optimum pH value of ~5. Increasing the adsorbent dose from 0.5 to 6–7 g enhanced the metal removal efficiency by ~60%, whereas a particle size increase from 50 to 300 µm decreased this value by about 30% for both Cu2+ and Pb2+ and both raw and treated DP/OP. Both breakthrough and exhaust times increased with increasing bed height of the fixed-bed column, and the effect observed for treated DP exceeded that observed for raw DP by a factor of two. Conversely, both breakthrough and exhaust times decreased with increasing initial metal concentration, particle size, and flow rate. Increasing the particle size from 100–150 to 300 µm changed the exhaust time by 8 h when treated DP was used for Pb2+ adsorption. The obtained linear regression coefficients (R2 = 0.9–0.99) suggest that both Thomas and Yoon–Nelson models are well-suited for predicting the adsorption performance of the present system.

For any river basin management, one needs tools to predict runoff at different time and spatial resolutions. Hydrological models are tools which account for the storage, flow of water and water balance in a watershed, which include exchanges of water and energy within the earth, atmosphere and oceans and utilise metrological data to generate flow. There are several sources of error in meteorological data, namely, through measurement at point level, interpolation, etc. When an erroneous input is passed to a model, one cannot expect an error free output from the prediction. Every prediction is associated with uncertainty. Quantification of these uncertainties is of prime importance in real world forecasting. In this study, an attempt has been made to study uncertainty associated with hydrological modelling, using the idea of data depth. To see the effect of uncertainty in rainfall on flow generation through a model, the input to a model was altered by adding an error and a different realisation was made. A Monte Carlo simulation generated a large number of hydrological model parameter sets drawn from the uniform distribution. The model was run using these parameters for each realisation of the rainfall. The parameters which are good for different realisations are more likely to be good parameters sets. For each parameter set, data depth was calculated and a likelihood was assigned to each parameter set based on the depth values. Based on this, the frequency distribution of the likelihood was analysed as well. The results show that uncertainty in hydrological modelling are multiplicative. The proposed methodology to assign prediction uncertainty is demonstrated using the ‘TopNet’ model for the Waipara river catchment located in the central east of the South Island, New Zealand. The results of this study will be helpful in calibration of hydrological model and in quantifying uncertainty in the prediction.

In this study, it was studied various advanced oxidation treatment processes; Fenton, UV/H2O2, UV/O3/H2O2 for treatability of hospital wastewaters containing antibiotics (cephalosporines). Taguchi’s L25 orthogonal array design was applied to design of advanced oxidation processes, for simplification of the analysis and calculations. 95,7%, 90,65%, 91,8% COD and 55,86%, 60,83%, 70,8% TOC removal efficiencies were obtained under the best operation conditions for UV/H2O2, UV/O3/H2O2 and Fenton processes, respectively. According to the ANOVA results, pH was of great importance in COD removal for Fenton. For the UV/H2O2 processes, H2O2 has significance in COD and TOC removals. As for the O3/UV/H2O2 processes, O3/UV reaction time was found as an important parameter effecting the removal rates. Also, cephalosporine antibiotic active compounds (cefradine and cefaclor) were degraded completely within minutes for all of the processes. Taguchi’s Method was found useful for the environmental applications and simplifications of advanced oxidation processes for treatment of hospital wastewaters and calculations.

Parallel to the increase in public concern about the safety of drinking water globally, the demand for bottled water has increased in almost every country. Although tap water is significantly cheaper than bottled water, consumers concerned about the safety of tap water. They still prefer the bottled water despite several checks implemented in tap water networks. The present paper aims to discuss network water quality in the city of Istanbul, Turkey and to present the findings on a related survey conducted by the authors. The survey was conducted with the participation of 980 individuals living in different districts in Istanbul and the findings were assessed to determine the public perception about tap water quality and bottled water consumption especially after the experienced years of drought and water quality concerns. Findings demonstrated that several individuals never drink tap water and certain individuals do not utilize tap water at all. It was found that only 4% in the surveyed group drink tap water without hesitation. Based on survey findings, the abovementioned group was mainly among the lowest income group in the sample. When purchasing bottled water, several individuals preferred the well-known brands. It was found that the most significant reasons for preferring bottled water were the nice taste of the bottled spring water, which was perceived not to exist in tap water. It was concluded that drinking water treatment facilities and regulations are required to cater the future quality demands. Furthermore, it was determined that adequate inspections and controls on network water are necessary.