In this paper, six different water quality indices were selected to assess the water quality for different uses and to identify the suitability of the selected indices in the assessment of the Danube River through a comprehensive comparison, in addition, to provide information on the spatial and temporal variations of the river water quality. The selected water quality indices are the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI), Oregon Water Quality Index (OWQI), Aquatic Toxicity Index (ATI), Universal Water Quality Index (UWQI), Overall Index of Pollution (OIP) and the Bascaron Water Quality Index (BWQI). Water quality dataset of 13 parameters obtained from 4 sampling points during a one-year monitoring period was considered in this study. The results demonstrated that the CCME WQI gave reasonable results in comparison to the raw data of the Danube River. The results of the other indices did not introduce representative outcomes of the raw data of the river. It was observed that some of these indices were biased and others have an eclipsing problem. However, these indices may be applicable to other water bodies.

In this paper carbon footprint is estimated for wastewater treatment plant Constanta South, Romania, by using a combined model from the available protocols for carbon footprint calculation. Off-site and on-site emissions were taken into account. The carbon footprint calculations were based on the operational data regarding power consumptions, sludge, chemicals and biogas production. A prediction for carbon footprint is done for upgrading wastewater treatment plant. For the current plant technology it is found that 0.44-0.54 kg CO2 eq have been released per cubic meter of treated wastewater for 2010-2013 years or 33.08-37.68 [kg CO2eq/PE and year]. For the upgraded plant, taking into account design data and the credit for biogas usage, it is found that the GHG emissions will be reduced at 0.17 kg CO2 eq per m 3 treated wastewater or 32.33 [kg CO2eq/PE and year].

In the present and projected context of an increasing worldwide demand for food, the intensification of climate change effects on agriculture, and the depletion and degradation of natural resources, global actions must be taken to assure future food security for all people. Improper practices along the food supply chain, from primary production to consumption, generate huge quantities of food waste. Building a circular bioeconomy that feeds recycled materials back into the economy and minimizes the loss of resources will be an important step in introducing the world’s food system to a sustainable path. The present case study describes an enclosed on-site composting system for food waste, operated in real-life conditions. The composting equipment was installed for a restaurant with specific needs in November 2020, located near a shopping center in Bucharest, the capital city of Romania. The physical, chemical, and biological characteristics of the compost came from a mix of food waste from a retail restaurant and sawdust pellets used as absorbent material, and these were analyzed to monitor compost quality and establish valorization opportunities. Two different monitoring campaigns were developed and the biological parameters were analyzed. The second monitoring campaign indicated that the compost was contaminated with Escherichia coli and Salmonella spp. When handled correctly and according to instructions, the composting process eliminates pathogens that may be present in food waste, such as Escherichia coli, Salmonella spp., etc., resulting in a high-quality compost that can be valorized in agriculture such as fertilizer or soil improver. Our results demonstrated that even when maintaining the same composition of raw materials in the composter, the quality and properties of the compost are greatly influenced by its operating conditions. Quality management procedures must be enforced and procedures must be strictly followed for the compost to be considered compliant. Compost that does not meet the requirements according to the regulation in force is again subjected to composting. If, after repeating the operation, the compost is still noncompliant, it is declared nonrecyclable waste, and must follow the specific procedure for such waste.

In Romania, the hydropower is the main form of renewable source with an important share in energy mix. Despite their valuable advantages on supplying energy and balancing the energy system, public acceptance, environmental, social and economic impact has become a common challenge in development of hydropower projects. Increasing of water consumption and raising awareness regarding available water resources leads to an integrated management approach of them. In this paper the water footprint is estimated for one of the largest Romanian hydropower project, namely Hydropower Plant Vidraru. The water footprint from hydroelectricity is evaluated considering electricity production of the hydropower plant, water footprint of dam construction and three different approaches to quantify water footprint of the reservoir: gross water consumption, net water consumption and water balance. Also, water footprint is assessed based on economic value of the reservoir using allocation coefficients for various purposes of the reservoir. It is estimated that economic benefit of the reservoir is 81.92·106 €/y, with hydroelectricity major contributor.

Drinking water treatment plays an important role in maintaining public health. Chlorine is the most often disinfectant used for microbiological protection of water. Required residual chlorine concentration must be in treated water when it leaves treatment plant, to comply with the regulations. The chlorine residual must be 0.5 mg/L at the entrance into the distribution system and 0.25 mg/l at consumers, according to the law. Any less and there is no guarantee that the water has adequate quality. The major problem that occurs as water flows between treatment plant and the consumer is water quality deterioration because of decreasing of residual chlorine concentration, especially for long residence times. This can be lead to high microbiological concentration in water downstream and it is necessary additional treatment with chlorine. This study presents a theoretical model based on dispersion equation, which was validated with experimental measurements in drinking water mains that supply Ramnicu-Valcea town, Romania.