• Energy Research
• Closed Access close
• Open Source close
• 6. Clean water close
• PL close

To examine the effects of the culture age, illuminance intensity and changes in these parameters during activation on hydrogen generation process carried out by purple nonsulfur Rhodobacter sphaeroides bacteria.The following parameters were determined in all experiments: the amount of hydrogen evolved (measured using gas chromatography), biomass increase as dry mass, pH values and consumption of organic substance as chemical oxygen demand (COD). The medium used in the process of activation and hydrogen generation contained malic acid (15 mmol) and sodium glutamate (2 mmol). The optimum age of bacteria was 12-24 h and the best intensity of illuminance was found to be 5 cd sr m-2 on activation and 9 cd sr m-2 on hydrogen generation. These conditions provided hydrogen evolution of 1.39 l l-1 of the medium with the highest specific hydrogen production of 0.146 l H2 l-1 medium h-1 g-1 inoculum. An increase in the illuminance intensity resulted in a slight inhibition of the process.The activation stage of bacteria has a significant effect on the parameters of hydrogen photogeneration. The optimization of the activation stages allowed a shortening of the time of hydrogen generation and of the period after which hydrogen evolution starts.An innovative method of bacteria activation before the initiation of the hydrogen generation process has been used to optimize this process. The shortening of the process duration as well as the twice higher hydrogen yield can help in the designing of other systems (including also those operating under solar irradiation) in which R. sphaeroides bacteria are to be applied.

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.

A technological solution was developed to process slaughter waste and farm manure and transform them into organic and mineral fertilizers. It has been shown that the formation of an enclosure on a goose farm from nitrogen-binding substances (brown coal, a mixture of brown coal with magnesite, used ash substrate) has a positive effect on reducing nitrogen emissions, even to about 80%. The presented solution is in line with ecological trends and ensures comprehensive management of agri-food waste. It reduces the loss of valuable nutrients from renewable sources, increases the efficiency of fertilizers and reduces the environmental nuisance of poultry farms. Organic-mineral fertilizers made from slaughterhouse waste and poultry manure were as effective as expensive commercial mineral fertilizers. New fertilizers helped to obtain a yield similar to the groups fertilized with mineral fertilizers: 11 t per ha for maize (grain), 0.8 t per ha for mustard (seed), 10 kg per 1 m2 of radish (all), and 18.5 kg per 1 m2 of beet (whole) while reducing production costs thanks to the use of waste materials.

Abstract The experimental study on oxygen and steam gasification and co-gasification of hard coal and sewage sludge to hydrogen-rich gas was performed in the laboratory scale fixed bed gasifier equipped with an auxiliary gasification agents pre-heating system, simulating the utilization of an excess High Temperature Reactor (HTR) heat. The allothermal gasification and co-gasification tests were performed on fuel blends of coal and sewage sludge of the total mass of 10 g and biowaste content of 20% and 40%w/w in three system configurations. In the first one the reactor was heated up with a resistance furnace to the temperature of 700 °C in the inert gas (nitrogen) atmosphere. When the temperature inside the reactor was stable, oxygen and steam of the temperature of approximately 100 °C were introduced into the reactor. In the second system, after the reactor was heated up to 700 °C, the heating of the reactor was switched off and oxygen and steam were pre-heated to the temperature of 700 °C and fed into the reactor. In the third system a fuel sample in the reactor was heated to the temperature 700 °C and the set temperature was maintained with the resistance furnace. The results showed that sufficient thermal energy required for an effective oxygen/steam gasification process was generated in systems with the external heating of the reactor. The highest hydrogen contents in gas were reported in coal gasification, irrespective of the system configuration. The total hydrogen volume decreased with increasing biomass content in a fuel blend in all studied system configurations.

Abstract The use of amine scrubbing methods for reducing CO2 emission from burning fossil fuels is growing in popularity. A major challenge of carbon capture methods using amines is high energy consumption. Moreover, the emission of amines from the carbon capture plant gains increasing attention due to environmental concerns. The amines may evaporate from the solution or be released in the form of an aerosol and enter the atmosphere. In order to determine the amines emission, experimental research was conducted using a process development unit. The composition of the gases from the absorber and desorber were measured using a Fourier Transform Infrared (FTIR) gas analyser. A solvent blend of 2-amino-2-methyl-1-propanol (AMP) and piperazine was utilised. Synthetic flue gas containing 12.7–12.9 % vol. (dry basis) of CO2 was directed to the absorber with a flow rate of 100 m3/h. Fresh water was supplied to the top of the absorber to maintain the water balance. No other form of water wash was used. The major components that were emitted together with the treated gas were ammonia and AMP. The produced CO2 contained traces of amine, ammonia and formic acid. The concentration of other degradation products was below the limit of quantification. Increasing the lean solvent temperature by 15 °C resulted in an increase in AMP emission by over 50 ppm. By analysing the vapour pressure literature data with obtained results, the emission was considered mainly as vapour-based. Water dosing at the top of the absorber proved to be effective in reducing amine emissions.

The aim of this work was to analyze the impact of three different moisture contents (MC), at 45% MC, 65% MC, 75% MC, on the degradation of cellulose, hemicellulose, and lignin during fungi treatment by Flammulina velutipes of Agropyron elongatum 'BAMAR' and on biogas production. The analysis of chemical composition shown that F. velutipes had greater selectivity for lignin biodegradation with the highest hemicellulose and lignin removal at 29.1% and 35.4%, respectively, and lowest cellulose removal (20.48%) at 65% MC. F. velutipes cultivated at 65% MC increased biogas production of 398.07Ndm(3)kg(-1)VS(-1), which was 120% higher than the untreated sample. These treatment conditions resulted in 134% more methane yield compared with untreated sample. The results of this study suggested that A. elongatum is a potential biomass for biogas production in agriculture biogas plant and white-rot fungus F. velutipes provides an effective methods for improve biodegradation of A. elongatum.

Nutrient removal performances of sequencing batch reactors using granular sludge for intensified biological wastewater treatment rely on optimal underlying microbial selection. Trigger factors of bacterial selection and nutrient removal were investigated in these novel biofilm systems with specific emphasis on polyphosphate- (PAO) and glycogen-accumulating organisms (GAO) mainly affiliated with Accumulibacter and Competibacter, respectively. In a first dynamic reactor operated with stepwise changes in concentration and ratio of acetate and propionate (Ac/Pr) under anaerobic feeding and aerobic starvation conditions and without wasting sludge periodically, propionate favorably selected for Accumulibacter (35% relative abundance) and stable production of granular biomass. A Plackett-Burman multifactorial experimental design was then used to screen in eight runs of 50 days at stable sludge retention time of 15 days for the main effects of COD concentration, Ac/Pr ratio, COD/P ratio, pH, temperature, and redox conditions during starvation. At 95% confidence level, pH was mainly triggering direct Accumulibacter selection and nutrient removal. The overall PAO/GAO competition in granular sludge was statistically equally impacted by pH, temperature, and redox factors. High Accumulibacter abundances (30-47%), PAO/GAO ratios (2.8-8.4), and phosphorus removal (80-100%) were selected by slightly alkaline (pH > 7.3) and lower mesophilic (<20 °C) conditions, and under full aeration during fixed 2-h starvation. Nitrogen removal by nitrification and denitrification (84-97%) was positively correlated to pH and temperature. In addition to alkalinity, non-limited organic conditions, 3-carbon propionate substrate, sludge age control, and phase length adaptation under alternating aerobic-anoxic conditions during starvation can lead to efficient nutrient-removing granular sludge biofilm systems.

In this study, the anaerobic mesophilic co-digestion of food waste (FW) with municipal sewage sludge (MSS) and slaughterhouse waste (SHW) was undertaken in 3-dm3 laboratory reactors as well as in 50-dm3 reactors operated in semi-continuous conditions. The highest methane yield of around 0.63 m3 CH4/kgVSfed was achieved for the mixture of FW and SHW treated in the laboratory digester operated at solids retention time (SRT) of 30 days, whereas the co-digestion of FW with MSS under similar operating conditions produced 0.46 m3 of methane from 1 kgVSfed. No significant differences between methane yields from laboratory digesters and large-scale reactors were reported. The conditioning tests with the digestates from reactor experiments revealed the highest efficiency of inorganic coagulants among all investigated chemicals, which applied in a dose of 10 g/kg allowed to reduce capiliary suction time (CST) of the digestate below 20 s. The combined conditioning with coagulants and bentonite did not further reduce the CST value but improved the quality of the digestate supernatant. In particular, the concentrations of suspended solids, COD as well as metals in the supernatant were considerably lowered.