Climate change, manifested by long term periods of drought to heavy rainfall, may remarkably modify river flow regimes. We hypothesize that flow prevailing in a given year determines water chemistry of the Carpathian Raba River above and below Dobczyce Reservoir (southern Poland), used for drinking purposes. Based on the mean annual river flow for years 1991‒2017, hydrologically dry (HD), hydrologically average (HA)and hydrologically wet (HW) years were distinguished. We found significant differences in the values of most studied physicochemical parameters of river water above and below the reservoir between studied hydrological years (for a period of April‒November). In HD years, the water above the dam had significantly higher temperature and values of conductivity (point pollution source, groundwater inflow), while lower ones of nutrients NO3- and P-tot (diffuse pollution) compared to those in HA and/or HW years. The best GLM models for mean monthly flows above and below the dam include 3‒5 factors among which conductivity and NO3- concentration were always present. The reservoir in different ways influences the water chemistry below the dam in HD, HA and HWyears. The impact of flow on the water quality in hydrologically varied years is discussed. The obtained results are important for appropriate management in catchment basins of mountain rivers and the protection of dam reservoirs against the eutrophication processes in changing climate and flow regime.

Water quality is an important criterion for evaluating the suitability of water for drinking and domestic purpose. The main objective of this study was to investigate the physicochemical characterization of groundwater for drinking water con-sumption. Ten captured sources were selected from three aquifers including the Guelma Mio-Plio-Quaternary alluvial ba-sin; the Senonian Heliopolis Neritic limestone aquifer, and the Eocene limestones of Ras El Agba-Sellaoua aquifer. The analyses concerned the periods of high water in May 2017 and low water in August 2017. Twelve parameters were deter-mined for the water samples: pH, T (°C), EC, Ca2+, Mg2+, Na+, K+, Cl–, HCO3–, SO42–, NO3–, TH (hydrotimetric degree), TAT (total alkalinity titration). The interpretation of the various analytical results allowed the determination of the chemical facies and the classification of the groundwater aquifers as follows: (i) in the alluvial layer, the gypsiferous marl substratum and the clays of the three terraces (high, medium and low) have given the water a chlorinated calcium chemical facies in the east part of the study area and travertines feeding partly alluvial layer, and have given a bicarbonated calcium water facies in the west, (ii) in the Senonian of Heliopolis limestone and Eocene carbonate formations of Ras El Agba- -Sellaoua, the chemical facies are calcium bicarbonate. Water isotopes (δ18O and δD) helped to determine the origin of groundwater. Overall, the groundwater in the area is hard and has significant to excessive mineralization. It is progressivelydegraded in the direction of flow, especially in the Guelma alluvial aquifer.

The research aims to study the purification performance of a local and natural material as an input or as a biological filter for treating urban domestic wastewater. For this purpose, pozzolan was used as the biofiltration support that was provided from Beni Saf located in the North-West of Algeria. Tests were carried out with a specially modified pilot unit (TE900) for wastewater treatment over a period of four months.
To assess the efficiency of the treatment, two main parameters have been focused on – the height of the sprinkler filter (40 cm and 80 cm) and the flow rate (10, 16, and 25 dm ³∙h ^–1). Physicochemical and bacteriological analyses were carried out on raw wastewater and treated water. The obtained results show that the Beni Saf pozzolan-filled trickling filter eliminates a large fraction of the studied pollutants. The purification yields obtained are fairly encouraging; 98% for turbidity, 88% for suspended solids ( SS), 94% for chemical oxygen demand ( COD), and 98% for biological oxygen demand ( BOD ₅). As for bacterial indicators, the formation of biofilms has significantly reduced bacterial activity with a percentage of over 80%.
It can be concluded that the reduction of pollutant parameters clearly indicates the effectiveness of the treatment by this ecological process. Therefore, the use of local and natural materials for wastewater treatment can be a promising alternative based on sustainable environmental technologies and development.

This study aimed at evaluating water quality of groundwater wells (GWWs) in Wadi Shati, Libya, and assessing its suitability for drinking. Water samples were collected from 17 GWWs and subjected to laboratory testing for 24 physical and chemical water quality parameters (WQPs). Analysis uncovered that the recorded values of 11 WQPs were consistent with the Libyan drinking water quality standard (DWQS). These parameters were pH, temperature (T), acidity, alkalinity, electrical conductivity (EC), sodium, potassium, calcium, magnesium, zinc, and cadmium. However, values of colour and turbidity exceeded the maximum levels set by the Libyan DWQS at five out of the 17 study wells. Likewise, concentrations of chloride (Cl ⁻), sulphate (SO ₄ ²⁻), and ammonia (NH3) violated the local DWQS in three locations, each. Additionally, concentrations of phosphate (PO ₄ ³⁻), iron, manganese, chromium, and nickel exceeded their maximum allowable concentrations according to the Libyan DWQS. The levels of these five parameters are alarming. Overall, the 17 studied GWWs suffer from varying levels of pollution that, mostly, arise from domestic and agricultural sources, e.g., septic tank seepage and agricultural drainage of agro-chemicals like fertilisers and pesticides. The results of this study emphasise that routine monitoring of groundwater resources plays a vital role in their sustainable management and stresses that water quality data are critical for characterisation of pollution, if any, and for protection of human health and ecosystem safety. Our results serve as guideline for sustainable management of water quality in the Wadi Shati District.

This study aims to assess the water quality and determine the pollution index of the Bedadung River in the urban-area segment of Jember Regency, East Java. The sampling in the urban segment of Jember was conducted in May 2019 at five different locations, namely Slamet Riyadi Street, Mastrip Street, Bengawan Solo Street, Sumatra Street, and Imam Bonjol Street. The pollution index assessment refers to the Decree of the State Minister for the Environment of Indonesia Republic number 115 of 2003. The analysis showed that the parameters of TDS, TSS, pH, COD, BOD, NH3-N, Co, Cd, Cu, Zn, H2S, Cl–, SO4, oil and fats, MBAS, NO2-N, Fe, Pb, F, Cl2, NO3-N, phenol, and As did not exceed the quality standards. The parameters PO4, CN, total coliform, and faecal coliform were found to breach the quality standards at the 5 water sam-pling points. Total coliform and faecal coliform were the dominant pollutants in this segment. Therefore, the parameters of PO4, total coliform, and faecal coliform were considered as indicators of pollution arising from domestic and agricultural activities. The pollution index values for the five sampling locations ranged from 7.21 to 8.23. These scores indicate that the Bedadung River section that passes through the urban segment in Jember is classified as being in the moderately pollut-ed category. This preliminary rapid assessment is therefore one of the considerations for the management of water quality in the Bedadung River section that passes through the urban area of Jember.