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The present study focused on carbon to nitrogen ratio (C/N) and organic loading rate (OLR) optimization of goose manure (GM) and wheat straw (WS). Dealing the anaerobic digestion of poultry manure on industrial scale; the question of optimum C/N (mixing ratio) and OLR (daily feeding concentration) have significant importance still lack in literature. Therefore, Batch and CSTR co-digestion experiments of the GM and WS were carried out at mesophilic condition. The alkali (NaOH) solubilization pretreatment for the WS had greatly enhanced its anaerobic digestibility. The highest methane production was evaluated between the C/N of 20-30 during Batch experimentation while for CSTRs; the second applied OLR of (3g.VS/L.d) was proved as the optimum with maximum methane production capability of 254.65ml/g.VS for reactor B at C/N of 25. The C/N and OLR regression optimization models were developed for their commercial scale usefulness.

The present study focused on carbon to nitrogen ratio (C/N) and organic loading rate (OLR) optimization of goose manure (GM) and wheat straw (WS). Dealing the anaerobic digestion of poultry manure on industrial scale; the question of optimum C/N (mixing ratio) and OLR (daily feeding concentration) have significant importance still lack in literature. Therefore, Batch and CSTR co-digestion experiments of the GM and WS were carried out at mesophilic condition. The alkali (NaOH) solubilization pretreatment for the WS had greatly enhanced its anaerobic digestibility. The highest methane production was evaluated between the C/N of 20-30 during Batch experimentation while for CSTRs; the second applied OLR of (3g.VS/L.d) was proved as the optimum with maximum methane production capability of 254.65ml/g.VS for reactor B at C/N of 25. The C/N and OLR regression optimization models were developed for their commercial scale usefulness.

In this study, Pennisetum giganteum (PG) was investigated as lignocellulosic feedstock to be pretreated by the acidic and basic deep eutectic solvents (DESs) to generate monomeric sugars. The basic DESs showed excellent efficiency of delignification and saccharification. ChCl/MEA can remove 79.8 % lignin and reserve 89.5 % cellulose. As a result, 95.6 % glucose and 88.0 % xylose yield were obtained, significantly enhanced 9.4 and 15.5 times in contrast with those of the unpretreated PG. The 3D microstructures of raw and pretreated PG were constructed for the first time to better investigate the pretreatment effect on its structure. The increasing porosity (20.5 %) and the reducing CrI (42.2 %) contributed in enhancing enzymatic digestion. Moreover, the recyclability of DES indicated that at least 90 % DES was recovered and 59.5 % lignin still can removed with 79.8 % glucose were obtained after five recycling cycles. Meanwhile, 51.6 % lignin was recovered throughout the recycling process.

In this study, Pennisetum giganteum (PG) was investigated as lignocellulosic feedstock to be pretreated by the acidic and basic deep eutectic solvents (DESs) to generate monomeric sugars. The basic DESs showed excellent efficiency of delignification and saccharification. ChCl/MEA can remove 79.8 % lignin and reserve 89.5 % cellulose. As a result, 95.6 % glucose and 88.0 % xylose yield were obtained, significantly enhanced 9.4 and 15.5 times in contrast with those of the unpretreated PG. The 3D microstructures of raw and pretreated PG were constructed for the first time to better investigate the pretreatment effect on its structure. The increasing porosity (20.5 %) and the reducing CrI (42.2 %) contributed in enhancing enzymatic digestion. Moreover, the recyclability of DES indicated that at least 90 % DES was recovered and 59.5 % lignin still can removed with 79.8 % glucose were obtained after five recycling cycles. Meanwhile, 51.6 % lignin was recovered throughout the recycling process.

The objective of the work reported here was to determine whether the ratio of COD/Nox has an impact on poly-beta-hydroxybutyrate (PHB) metabolism in activated sludge. Furthermore, it was tested if the ratio influenced the percentage use of organic compounds present in wastewater, for endogenous respiration, oxidation, accumulation and denitrification. Gas flow rate in SBR reactor was controlled by thermal mass flow controller (TMFC). Constant amount of air entering sequencing batch reactor was automatically adjusted to stable set-point 2mg O2 L(-1). It means that DO concentration in the reactor could change with oxygen uptake. During the filling period and part of the reaction time DO was nearly zero. Feast period of the external substrate availability and famine period of little amount or no external carbon availability were determined. At 23 h of the reaction time, and COD/Nox ratio 8, denitrification took place only during feast period. What was interesting, poly-beta-hydroxybutyrate degradation was observed in the feast period as well. However, at 11h of the reaction time and COD/Nox ratio 37, denitrification occurred in feast and famine period. In the feast period PHB was accumulated and in the famine period was used as the endogenous carbon source. COD consumption to reduce 1mg N-nitrate was ranging from 1.15 to 6.26 depending on carbon source and increased when exogenous and endogenous carbon were used by activated sludge. The increase in PHB content from 0.25 to 0.43 Cmol/Cmol resulted in a double increase in the amount of nitrogen removed due to denitrification was observed.

The objective of the work reported here was to determine whether the ratio of COD/Nox has an impact on poly-beta-hydroxybutyrate (PHB) metabolism in activated sludge. Furthermore, it was tested if the ratio influenced the percentage use of organic compounds present in wastewater, for endogenous respiration, oxidation, accumulation and denitrification. Gas flow rate in SBR reactor was controlled by thermal mass flow controller (TMFC). Constant amount of air entering sequencing batch reactor was automatically adjusted to stable set-point 2mg O2 L(-1). It means that DO concentration in the reactor could change with oxygen uptake. During the filling period and part of the reaction time DO was nearly zero. Feast period of the external substrate availability and famine period of little amount or no external carbon availability were determined. At 23 h of the reaction time, and COD/Nox ratio 8, denitrification took place only during feast period. What was interesting, poly-beta-hydroxybutyrate degradation was observed in the feast period as well. However, at 11h of the reaction time and COD/Nox ratio 37, denitrification occurred in feast and famine period. In the feast period PHB was accumulated and in the famine period was used as the endogenous carbon source. COD consumption to reduce 1mg N-nitrate was ranging from 1.15 to 6.26 depending on carbon source and increased when exogenous and endogenous carbon were used by activated sludge. The increase in PHB content from 0.25 to 0.43 Cmol/Cmol resulted in a double increase in the amount of nitrogen removed due to denitrification was observed.

Multi-generation or polygeneration is considered to be a potential sustainable energy solution. To assess environmental sustainability of multi-generation, life cycle assessment (LCA) is a useful tool. In this paper, environmental impact of polygeneration using an agro waste (rice straw) is assessed by LCA. Then it is compared with stand alone conventional plants with same utility outputs. Power, ethanol, heating and cooling are utility outputs of the polygeneration plant. System boundary for this polygeneration is defined for surplus biomass only. Exergy based allocation method is used for this analysis. Results of LCA are shown through both mid-point and end-point indicators. Results indicate that polygeneration with surplus rice straw is more environment-friendly than conventional stand-alone generation of same utilities.

Multi-generation or polygeneration is considered to be a potential sustainable energy solution. To assess environmental sustainability of multi-generation, life cycle assessment (LCA) is a useful tool. In this paper, environmental impact of polygeneration using an agro waste (rice straw) is assessed by LCA. Then it is compared with stand alone conventional plants with same utility outputs. Power, ethanol, heating and cooling are utility outputs of the polygeneration plant. System boundary for this polygeneration is defined for surplus biomass only. Exergy based allocation method is used for this analysis. Results of LCA are shown through both mid-point and end-point indicators. Results indicate that polygeneration with surplus rice straw is more environment-friendly than conventional stand-alone generation of same utilities.

Grassland biomass is suitable in numerous ways for producing energy. It is well established as feedstock for biogas production. The aim of this review is to summarize current knowledge on suitability and sustainability of grassland biomass for anaerobic digestion. In the first section grassland management for biogas feedstock as well as specifics of harvest, postharvest and digestion technology are described. Methane yields from grass are influenced by many factors. While the effects of some parameters such as grass species, cutting period and management intensity can be regarded as well known, other parameters such as preservation and processing still need investigation. In the second section economic aspects and environmental impacts are discussed. Profitability can be achieved depending on grass silage supply costs and the concept of anaerobic digestion and energy use. Grassland biomass for biogas production competes with other feedstock and other forms of grassland use, in particular animal husbandry. In developed countries a growing production of milk and meat is achieved with decreasing ruminant numbers, resulting in an increasing amount of surplus grassland with a remarkable bioenergy potential. In emerging and developing countries a rapidly rising demand for and production of milk and meat induce growing pressure on grasslands, so that their use for animal feed presumably will take priority over use for bioenergy. Grasslands provide a variety of essential environmental benefits such as carbon storage, habitat function, preservation of ground and surface water quality. When producing biogas from grassland these benefits will remain or even grow, providing appropriate grassland management is implemented. In particular, greenhouse gas emissions can be considerably reduced.