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Slaughterhouse wastewaters are characterized by a high organic content, mainly composed of proteins and fats. Therefore, these wastewaters should be treated efficiently prior to discharge into receiving bodies to avoid severe environmental pollution. This work aimed to characterize slaughterhouse wastewater generated in one province of Iran (Khuzestan), evaluating various suitability of biological treatment, assessing wastewater treatment plants performance and feasibility of wastewater reuse. Composite samples were collected from input and output of wastewater treatment plant during 6 months (spring and summer) and were analyzed for TSS, turbidity, temperature, conductivity, pH, COD, BOD₅, fat, total coliform and fecal coliform. Data analysis was done using Excel and SPSS software. The results showed that different quantities of wastewater were generated in any slaughterhouses of Ahvaz (120-600 l/d.sheep), Dezful (110-550 l/d.sheep), and Shushtar (139-694 l/d.sheep). Khuzestan slaughterhouses wastewater is classified by pollution severity as strong wastewater. The BOD₅/COD ranges from 0.3 to 0.5, which indicates applicability of biological treatment. Wastewater treatment plant of Ahvaz with anaerobic stabilization ponds and extended aeration activated sludge process has the highest removal efficiencies of pollutants. The result also indicated reuse of slaughterhouses effluent was not acceptable due to not comply with the standards of Iran. Finally, if safe use or disposal of these effluents is desired, blood capture from raw wastewater for reducing the amounts of organic loading must be implemented. Also, use of an appropriate treatment plant is noted.

The results indicated that the study areas face humid conditions, mostly due to the existence of high altitudes. Furthermore, the various climatic conditions are responsible for differentiations in seasonal analysis regarding the aridity conditions. The study areas related to the Mediterranean climate resulted more heterogeneous conditions compared with areas affected by the continental climate. Nevertheless, the created aridity spatial maps of trend analysis presented with differentiations, especially in the mountainous areas were an extreme downward trend is appeared. For the southern investigated area in Crete Island characterized purely by Mediterranean climate, the results were more moderate in terms of aridity conditions.

The study aims to evaluate soil erosion and investigate its spatial distribution by applying two empirical models, namely the Erosion Potential Model (EPM), also known as Gavrilovic method, and the RUSLE model at Venetikos River catchment, the largest and most important tributary of Aliakmonas River, located at Western Macedonia, Northern Greece. To that end, a GIS-based evaluation is adopted, leading to a more accurate result. The models were implemented both annually and inter-annually. The results were compared with the catchment’s “actual” mean annual sediment yield, computed by the sediment discharge measurements conducted on a monthly basis at its outlet, namely Grevena Bridge, by the Greek Public Power Corporation (PPC) during the time period from 1965 to 1982. The Gavrilovic model slightly underestimated the outcome in comparison to the RUSLE methodology which attributed relatively more accurate results, yet performed quite similarly at both time scales. The two approaches simulated the phenomenon quite satisfactory, showing acceptable precision and allowing identification of the most susceptible to erosion and degradation areas, constituting important predictive tools for soil and environmental management in this region.

Groundwater is one of the major parameters in maintaining ecology in many regions. As climate is one of the main factors which affects groundwater resources, the main objective of the present study is to assess the impact of rainfall changes on the groundwater system by projecting the future changes in the 21^st century (2021-2050 and 2071-2100). For this reason, the RegCM3 climate model precipitation data, which showed a reduction in rainfall, was entered in the steady-state groundwater flow model MODFLOW for the case study of a coastal aquifer in the eastern part of the Thermaikos Gulf (North Greece). The uprising urbanization in combination with the intensive cultivation have led to the overexploitation of the coastal aquifer and seawater intrusion. The groundwater flow simulation by using the MODFLOW code indicates a negative water budget and estimates the quantities of the seawater intrusion. According to the RegCM3 climate model, the precipitation reduction is estimated to be 4% during the period of 2021-2050, while the precipitation decrease is expected to be 22% during the period of 2071-2100. Furthermore, the natural recharge of the coastal aquifer is expected to be influenced by the precipitation reduction. Finally, the seawater intrusion amounts are expected to increase during these future periods and more specifically during the second period of 2071-2100.