Exploitation of experimental design methods and mathematical modeling for improving fermentative biohydrogen production processes

Abstract Considering the non-renewable nature of today's energy sources, alternative solutions need to be introduced to successfully fulfill the world's energy demands in the future. Biohydrogen production processes coupled to the treatment of different organic wastes might satisfy the requirements of a renewable and environmentally friendly energy carrier. A major drawback of this bioprocess is the low hydrogen production yield, thus, the optimization of the fermentation conditions is imperative for achieving a hydrogen-based economy. The most widely used optimization strategies refer to the design of experimental methods, by which certain factors are selected and deliberately varied in order to obtain the desired effects. In addition, the optimization process can be further improved through mathematical modeling and simulations. Some kinetic models have been proposed to describe the progress of substrate degradation and microbial growth coupled with hydrogen production and some soluble metabolite formation in a batch fermentationbased hydrogen production process. This review attempts to summarize the experimental design methods as well as the kinetic models and simulations that were used to investigate the effects of various factors on fermentative hydrogen production processes and to discuss the advantages and limitations of these optimization approaches

SLUDGE STRATEGY IN CARAS SEVERIN COUNTY AND REHABILITATION OF CONTAMINATED SITES

The sludge generation main source of Caraş-Severin County are the sewage treatment plants; the amount of sludge generated by the water treatment plants being insignificant. Because the annual amounts of sludge generated is high the processing, storage, recovery of sludge creates specific and complex engineering problems. The elaboration of the sludge strategy considered the quantities and quality, of current sludge, as well as those resulted after the completion of the construction works for the new water treatment and purification plants included in the Water - Water Waste Master Plan. Also, the sludge resulting from the implementation of the Integrated Waste Management System at the county level must be taken into account. The sludge strategy aims to provide on a medium term sustainable solutions for the final recovery / disposal of the sludge generated in accordance with the legal provisions and the national strategy. The paper presents one of the sustainable and viable options for sludge recovery in Caraş-Severin County, using them as an artificial soil for re-ecological contaminated sites (33), amounting to 629 hectares: mining waste dumps, tailings ponds and non-compliant deposits

Flood risk management objectives and Romanian catalogue of potential measures for flood prevention, protection and mitigation

In order to draw up the Flood Risk Management Plans, in Romania have been identified two types of objectives: strategic and operational. In defining the strategic objectives of flood risk management for Romania, the approach agreed at the ICPDR was taken into consideration. Furthermore, these strategic objectives set at national level were detailed in specific objectives that covers the 4 major categories of negative consequences established by Floods Directive mentioned above. In order to facilitate / structural and non-structural measures selection for 11 River Basin Authorities from Romania, a catalogue of potential measures at national level was elaborated. The proposed measures are following main areas of action closely linked to the cycle of flood risk management: Prevention, Protection, Preparedness, Awareness and Recovery. The paper presents the objectives of flood risk management established in Romania, associated indicators and nationwide catalogue of potential measures. At the same time it is presented a case study on potential measures proposed at the level of basin

Flood risk management objectives and Romanian catalogue of potential measures for flood prevention, protection and mitigation

In order to draw up the Flood Risk Management Plans, in Romania have been identified two types of objectives: strategic and operational. In defining the strategic objectives of flood risk management for Romania, the approach agreed at the Danube Commission (ICPDR) was taken into consideration. Furthermore, these strategic objectives set at national level were detailed in specific objectives that cover the 4 major categories of negative consequences established by Floods Directive mentioned above. In order to facilitate / structural and non-structural measures selection for 11 River Basin Authorities from Romania, a catalogue of potential measures at national level was elaborated. The proposed measures are following main areas of action closely linked to the cycle of flood risk management: Prevention, Protection, Preparedness, Awareness and Recovery. The paper presents the objectives of flood risk management established in Romania, associated indicators and nationwide catalogue of potential measures. At the same time a case study is presented on potential measures proposed at the level of basin

Flood risk management objectives and Romanian catalogue of potential measures for flood prevention, protection and mitigation

In order to draw up the Flood Risk Management Plans, in Romania have been identified two types of objectives: strategic and operational. In defining the strategic objectives of flood risk management for Romania, the approach agreed at the ICPDR was taken into consideration. Furthermore, these strategic objectives set at national level were detailed in specific objectives that covers the 4 major categories of negative consequences established by Floods Directive mentioned above. In order to facilitate / structural and non-structural measures selection for 11 River Basin Authorities from Romania, a catalogue of potential measures at national level was elaborated. The proposed measures are following main areas of action closely linked to the cycle of flood risk management: Prevention, Protection, Preparedness, Awareness and Recovery. The paper presents the objectives of flood risk management established in Romania, associated indicators and nationwide catalogue of potential measures. At the same time it is presented a case study on potential measures proposed at the level of basin

Exploitation of experimental design methods and mathematical modeling for improving fermentative biohydrogen production processes

Considering the non-renewable nature of today's energy sources, alternative solutions need to be introduced to successfully fulfill the world's energy demands in the future. Biohydrogen production processes coupled to the treatment of different organic wastes might satisfy the requirements of a renewable and environmentally friendly energy carrier. A major drawback of this bioprocess is the low hydrogen production yield, thus, the optimization of the fermentation conditions is imperative for achieving a hydrogen-based economy. The most widely used optimization strategies refer to the design of experimental methods, by which certain factors are selected and deliberately varied in order to obtain the desired effects. In addition, the optimization process can be further improved through mathematical modeling and simulations. Some kinetic models have been proposed to describe the progress of substrate degradation and microbial growth coupled with hydrogen production and some soluble metabolite formation in a batch fermentationbased hydrogen production process. This review attempts to summarize the experimental design methods as well as the kinetic models and simulations that were used to investigate the effects of various factors on fermentative hydrogen production processes and to discuss the advantages and limitations of these optimization approaches

Exploitation of experimental design methods and mathematical modeling for improving fermentative biohydrogen production processes

Considering the non-renewable nature of today's energy sources, alternative solutions need to be introduced to successfully fulfill the world's energy demands in the future. Biohydrogen production processes coupled to the treatment of different organic wastes might satisfy the requirements of a renewable and environmentally friendly energy carrier. A major drawback of this bioprocess is the low hydrogen production yield, thus, the optimization of the fermentation conditions is imperative for achieving a hydrogen-based economy. The most widely used optimization strategies refer to the design of experimental methods, by which certain factors are selected and deliberately varied in order to obtain the desired effects. In addition, the optimization process can be further improved through mathematical modeling and simulations. Some kinetic models have been proposed to describe the progress of substrate degradation and microbial growth coupled with hydrogen production and some soluble metabolite formation in a batch fermentation-based hydrogen production process. This review attempts to summarize the experimental design methods as well as the kinetic models and simulations that were used to investigate the effects of various factors on fermentative hydrogen production processes and to discuss the advantages and limitations of these optimization approaches

Revealing the factors influencing a fermentative biohydrogen production process using industrial wastewater as fermentation substrate

Background: Biohydrogen production through dark fermentation using organic waste as a substrate has gained increasing attention in recent years, mostly because of the economic advantages of coupling renewable, clean energy production with biological waste treatment. An ideal approach is the use of selected microbial inocula that are able to degrade complex organic substrates with simultaneous biohydrogen generation. Unfortunately, even with a specifically designed starting inoculum, there is still a number of parameters, mostly with regard to the fermentation conditions, that need to be improved in order to achieve a viable, large-scale, and technologically feasible solution. In this study, statistics-based factorial experimental design methods were applied to investigate the impact of various biological, physical, and chemical parameters, as well as the interactions between them on the biohydrogen production rates.Results: By developing and applying a central composite experimental design strategy, the effects of the independent variables on biohydrogen production were determined. The initial pH value was shown to have the largest effect on the biohydrogen production process. High-throughput sequencing-based metagenomic assessments of microbial communities revealed a clear shift towards a Clostridium sp.-dominated environment, as the responses of the variables investigated were maximized towards the highest H2-producing potential. Mass spectrometry analysis suggested that the microbial consortium largely followed hydrogen-generating metabolic pathways, with the simultaneous degradation of complex organic compounds, and thus also performed a biological treatment of the beer brewing industry wastewater used as a fermentation substrate.Conclusions: Therefore, we have developed a complex optimization strategy for batch-mode biohydrogen production using a defined microbial consortium as the starting inoculum and beer brewery wastewater as the fermentation substrate. These results have the potential to bring us closer to an optimized, industrial-scale system which will serve the dual purpose of wastewater pre-treatment and concomitant biohydrogen production