Volume 23 - 2021

Catechol is used as an antioxidant, fungicide, and polymerization inhibitors in a variety of industries such as petrochemical. Catechol must be removed from effluents before it enters to environment. This study aimed to investigate combined UV radiation and persulfate process in removal of catechol from aqueous solutions. All experiments were performed in a batch reactor. Data analysis were done with Design of Experiment (DoE) software. The effects of various variables such as pH, initial persulfate concentration, and initial Catechol concentration were investigated. The findings indicated with increases in persulfate concentration and decrease in catechol concentrations, the removal efficiency increased. Acidic pH and UV radiation were the leading factors in removal of catechol. The optimum pH, persulfate concentration, and catechol concentration were obtained 7, 0.04 M, and 100 mg l-1, respectively. More removes of catechol was achieved in optimum conditions within contact time of 60 min. The synergic effects of UV and persulfate radical were about 88%. Approximately 60% of catechol was mineralized within contact time of 60 min. Persulfate radicals resulting from UV/S2O82- were the main effective oxidants in removal and mineralization of catechol. Owing to high removal efficiency of persulfate compounds which are, also, abundant and inexpensive, these can be applied in removal of persistent organic pollutants from aqueous solutions.

The Mediterranean region is expected to present reduced availability of water resources due to climate change. This study aims to assess the potential hydrological responses to climate change in the Kastoria basin (Western Macedonia, Northern Greece) for the period 2019-2078. Climate projections from eight regional climate models from EURO-CORDEX were bias-adjusted using the linear scaling method. The bias-adjusted climate data were used to force the FeFLOW hydro-logical model to predict the discharge of the Kastoria aquifer towards lake Orestiada along with the projected groundwater level distribution. Precipitation (temperature) shows a tendency to decrease (increase) mainly in late spring to early autumn while increase (decrease) in the other sea-sons. Moreover, results indicate a significant increase in temperature and a slight decrease in precipitation towards 2078, while the predicted groundwater level of Kastoria aquifer will reduce slightly. However, the future hydrological behavior of the basin indicates a substantial reduction by approximately 15% of total water yield towards the end of the century.

Different aquatic ecological zones exhibit different gradients present heterogeneous algal composition. The algal community in the water column and sediment with certain environmental factors were screened monthly for twelve months with standard methods, to ascertain disparate in algal distinction. Air and water temperature, conductivity, water depth, dissolved oxygen and nutrients were the primary factors that influenced the algal abundances and diversities. 90% of the algal communities were benthic (33 species) and planktic-benthic (21) with 10% truly planktonic (6) species. Comparatively, the water-column benthic and planktic-benthic surpasses the benthic species associated with the sediment. The PCA on the habitat- type abundance revealed that 99.5% benthic algae in the water column are responsible for the total algal- abundance variance. Species richness and Shannon diversity indices were low, which ANCOVA and Levene tests demonstrated significantly equal and homogeneity of algae respectively between the studied zones. The linear relationships between the algae in the water and sediment zones were non-significant (p>0.05). The Euclidean algorithm confirmed algal community similarity in the water column and sediment. Species diversity limits, a high proportion of benthic algae in the planktonic, and significant homogenous algae in water and sediment. Signatures sediment destruction, breaking and dislodgement and uplifting of associated bottom algae, and the constant mixing of the water column and sediment due to sand dredging in the study area. Machines and human-dredging has exacerbated the abundance of benthic algae in the water column.

With the rising interest for sustainable power source and ecological security, anaerobic digestion of biogas technology has attracted considerable attention within the scientific researchers. This paper proposes a new research achievement on biogas production from Rice Mill Wastewater (RMW) with the utilization of anaerobic digester. An anaerobic digester is maintained with RMW and distillery anaerobic sludge at mesophilic temperature condition for 15 days as stabilization mode. After attaining stabilization stage, studies continued to examine the effect of Organic Loading Rate (OLR) and Hydraulic Retention Time (HRT) on the mesophilic anaerobic digestion of RMW. The OLR of the anaerobic reactor increased stepwise from 0.25 to 3.91 Kg COD/m3/dayand HRT ranged from 1 to 32.0 days. The total chemical oxygen demand (TCOD) utilized was higher than 75% and the CH4 percentage of the biogas was 62.00-63.00% for the OLRs studied. The efficient working volume of the digester is preserved as 25% of distillery anaerobic sludge and 75% of rice mill wastewater, loaded at Mesophilic temperature conditions for study purpose. By changing the conditions of OLR and HRT, biogas production, methane yield and percentage of COD reduction is examined. An anaerobic sludge is utilized as a seeding material to biodegrade the organic pollutants present in the wastewater. It will enhance the biological treatment of effluent with anaerobic sludge in a continuous mode of activity.The result showed that the proposed analysis obtains more biogas production with reduced COD when compared with existing approaches.