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PubMed2006

A technical, economic and environmental comparison of composting and anaerobic digestion of biodegradable municipal waste.

Ireland produces two million tonnes per annum of biodegradable municipal solid waste. The implementation of the Landfill Directive (1999/31/EC) will lead to the construction of centralised biological facilities; these facilities may be either composting facilities or anaerobic digestion facilities. A technical, economic and environmental analysis of composting and anaerobic digestion is undertaken in this paper. The results of the analysis suggest that composting is economically preferable to anaerobic digestion at scales at or below 50 kt/a of biowaste treated. However when CH4-enriched biogas is produced for use as a transport fuel and excise duty is reduced, as allowed by the Biofuels Directive (2003/30/EC), then the economics of anaerobic digestion improve greatly. If 100% of excise duty is removed then anaerobic digestion is economically preferable to composting above 20 kt/a of biowaste treated. From an environment perspective anaerobic digestion saves more greenhouse gas due to displacement of fossil fuel powered energy. Anaerobic digestion with CH4-enriched biogas has the potential to save 1,451 kgCO2/t of biowaste treated as opposed to composting, which has the potential to save 1,190 kgCO2/t.

Anaerobiosis↗
PubMed2006

Sustainable approach for leachate treatment: electricity generation in microbial fuel cell.

Electricity generation from landfill leachate was examined by using both a dual-chamber microbial fuel cell (MFC) and a single chamber MFC. Experimental results showed that the maximum power density of 2060.19 mW/m3 in the dual-chamber MFC and that of 6817.4 mW/m3 in the single chamber MFC were obtained. It was recognized that the difference in internal resistance for two MFC systems was the main reason for resulting in the difference of power generation. Power generation as function of chemical oxygen demand (COD) in single chamber MFC showed a Monod-type relationship with Pmax of 5920.96 mW/m3 and Ks of 251.39 mg/L at an external resistance of 500 Omega. Cyclic voltammetry showed that electrons were directly transferred onto the anode by bacteria in biofilms, rather than self-produced mediators of bacteria in the solutions. At low COD concentration, electricity generation was limited by the anode due to kinetic limitation; while at high COD concentration, the cathode was shown to have more significant effects on the electricity generation than the anode. COD in leachate could be removed when it increases, mainly because oxygen diffused from the cathode was substantially reduced by aerobic or anoxic bacteria in the anode chamber, leading to the substrate loss. Removal of ammonium-nitrogen was not observed in the single chamber MFC. This novel technology provides an economical route for electricity energy recovery in leachate treatment.

Bacteria↗
PubMed2003

Hydrogen production from wastewater sludge using a Clostridium strain.

Limited data in literature revealed a relatively low hydrogen yield from wastewater sludge, ca. 0.16 mg/g-dried solids, using anaerobic fermentation. We demonstrated in this work a much higher hydrogen yield, around 1.1 mg-H2/g-dried solids using a clostridium strain isolated from the sludge sample. The formed hydrogen would be consumed after passing the peak value at around 30-36 h of fermentation. We examined the effects of employing five different pre-treatments on substrate sludge, but noted no appreciable enhancement in hydrogen yield as commonly expected for methane production. Since a vast amount of organic matters had been released to water after hydrogen fermentation, we externally dosed methanogenic bacteria to the fermented liquor to produce methane. The fermented liquor could produce more methane than the non-fermented sample, indicating that the dosed methanogenic bacteria readily utilized the organic matters derived from the fermentation test.

Bioelectric Energy Sources↗
PubMed2004

Biological hydrogen production by enriched anaerobic cultures in the presence of copper and zinc.

Batch experiments were carried out to examine the productions of hydrogen and volatile fatty acids from glucose by enriched anaerobic culture in the presence of Cu and Zn. Results showed the specific hydrogen production rate was enhanced by the dosage of Cu at 50-100 mg/dm3 or the dosage of Zn at 10-250 mg/dm3, but was inhibited by Cu over 200 mg/dm3 or Zn at 500 mg/dm3. The hydrogen production yield was enhanced by Cu of 5-400 mg/dm3 or Zn of 5-500 mg/dm3. Productions of acetate and propionate were inhibited by Cu of 5-400 mg/dm3 or Zn of 5-500 mg/dm3. On the other hand, production of butyrate was stimulated, whereas production of ethanol was not affected. In terms of the CI,50 values. Cu was more toxic than Zn. The modified Gompertz equation was able to properly describe the cumulative hydrogen production in the presence of Cu or Zn.

Bacteria, Anaerobic↗
PubMed2004

Anaerobic digestion and methane generation potential of rose residue in batch reactors.

In the study, anaerobic digestion of residues from rose oil industry was investigated by using a laboratory scale completely mixed batch reactor in volume of 10 L and 4 small reactors in volume of 400 mL. Ten liters reactor isolated with a water jacket and 0.4 L reactors settled into a water bath were operated at 35 +/- 1 degrees C. The study supplies biochemical methane potential of hydrolyzed and original residues. Experimental results showed that hydrolyzed rose residue produced a bit more methane than original residue. Methane production results were analyzed with first-order and Chen&Hashimoto's models, and Chen&-Hashimoto's model was found to be more suitable than first-order kinetic model.

Bacteria, Anaerobic↗
PubMed2004

Enhancing anaerobic fermentation of sewage sludge for increasing biogas generation.

The article presents results of biogas generation from sewage sludge after applying two pretreatment methods: sonification and thermal hydrolysis. Original results and literature data of the ultrasonic field influence on biogas generation were compared with literature data concerning effectiveness of the thermal hydrolysis. Sludge pretreatment by the ultrasonic field intensified the biogas production as the amounts of biogas was of ca. 20-24% higher, as compared to the nontreated sludge. The highest generation of biogas was observed after a shorter time. The degree of organic matter reduction was of 45-47%. The content of volatile fatty acids dropped down to 139 mg CH3COOH dm(-3) during 20 days. During the thermal pretreatment of sludge the amounts of generated biogas were ca. 25% higher, as compared to nontreated sludge. The maximum biogas production of 0.92 dm3 was observed in the day 9 of fermentation. To-date results indicate that efficiency of ultrasonic disintegration depends on sonification time, type of heads, as well as power and frequency transmitted to heads.

Bacteria, Anaerobic↗
PubMed2004

Acceleration of the decomposition rate of anaerobic biological treatment.

Anaerobic biological waste treatment offers advantages over aerobic systems in terms of lower energy requirements, less biological sludge production, and the potential for energy recovery in the form of biogas. The biogas produced can be used in a multiplicity of ways. The major drawback of this process is the slow growth rate of anaerobic microorganisms. Experimental studies have been performed to investigate the effect of yeast population on the rate of anaerobic decomposition. The experiments were conducted in three laboratory scale anaerobic reactors. The result of this study showed that the yeast population enhanced the bacterial growth rate in the anaerobic batch reactors, consequently the COD removal efficiency and biogas generation inside the reactors were enhanced.

Bacteria, Anaerobic↗
PubMed2001

Quantitative analysis of reproducible changes in high-voltage electrophotography.

OBJECTIVES: The existence of electromagnetic fields not generated by neuronal action or muscle stimulation remains controversial especially because they are difficulty to detect. We attempted to investigate the existence of electromagnetic fields associated with biologic systems using new image analysis techniques to analyze high-voltage electrophotography. DESIGN/SUBJECTS: Five energy practitioners (three males and two females) and five control subjects (four males and one female) participated in the study. Each practitioner had studied a formal training curriculum and was a professional energy practitioner. Images representing attempts of both energy practitioners and controls to elicit a change in electromagnetic emissions were captured by electrophotographic means. A statistical analysis on the comparison of "ON" vs. "OFF" states for the controls and practitioners in the study was made via digital representation of analogue images. RESULTS: Our interest was threefold: (1) to determine whether corona discharge patterns could be obtained and photographed and be reproducible; (2) to quantify some of the qualitative properties of the coronas; and (3) to determine if individuals can alter, at will, their electrophotographic images. We found a correlation between a change in the electromagnetic emissions for the body and the conscious desire of an energy practitioner to change this state. Analyses of individual finger coronas demonstrate statistically significant differences as analyzed by overall color changes and via analysis of individual sections of the various colors dominating the field. Control subjects were unable to produce statistically significant changes that were reproducible. Physiologic processes, such as changes in skin resistance, sweating, and surface blood constriction, have been suggested as an explanation of the colors and patterns that appear on the film in previous studies, but were not observed in this investigation. CONCLUSIONS: After controlling for the above variables and identifying reproducible and statistically significant changes, we believe the images created in our study represent the interaction of biologically generated electromagnetic fields interacting with the corona discharge created by the electrophotographic device.

Adult↗
PubMed2003

Alternative method of gifted identification using the AMI: an apparatus for measuring internal meridians and their corresponding organs.

OBJECTIVES: To determine if meridian energy (qi or bioelectricity), as measured by the Apparatus for Measuring the Internal Organs and their Corresponding Meridians (AMI), could distinguish between gifted and average boys and to gather evidence to assess if the AMI device could be effective as an educational diagnostic tool, specifically for identifying gifted children. DESIGN: Quasi-experimental design using discriminant analysis to determine how accurately the AMI could predict group membership previously determined by intelligence tests. SETTINGS/LOCATION: Practitioner's office within clinic in Albuquerque, New Mexico. SUBJECTS: Thirty-three (33 boys; gifted, n = 11 and average, n = 22) ranging in age from 9 to 12 years. OUTCOME MEASURES: Meridian nervous system energy levels as measured by the AMI. RESULTS: On average, boys in the gifted group had statistically significantly calmer nervous system measures than the boys in the average group. The discriminant function generated from the AMI nervous system measures accurately predicted group membership 70% of the time. Classification accuracy by groups indicated that 55% of the gifted cases and 82% of the average cases were correctly classified. Upon cross-validation, accuracy by group stayed consistent with the average group (82%) and improved with the gifted group (64%). CONCLUSIONS: Bioelectrical energy patterns of the nervous system, as measured by the AMI, could distinguish between gifted and average boys. The accuracy found in this current study using the AMI as a screening tool to detect giftedness is promising, however, further studies will need to be conducted to see if the findings can be replicated.

Bioelectric Energy Sources↗
PubMed2003

Laparoscopic gastric bypass surgery: equipment and necessary tools.

Advanced laparoscopy in the morbidly obese patient is technically challenging. Having the proper instrumentation and equipment available is a major component of technical success. Items routinely used during surgery performed on patients of normal size must often be modified or substituted when morbidly obese patients undergo surgery. In this article, we review the specific tools necessary for the safe and proper completion of laparoscopic Roux-en-Y gastric bypass, in addition to various alternatives that can be helpful when other procedures are performed on morbidly obese patients.

Bioelectric Energy Sources↗
PubMed1989

Energy requirement for early defibrillation.

The appropriate energy requirement for defibrillation of out-of-hospital ventricular fibrillation has been a matter of discussion. We analysed the effects of 360 J, 200 J or a combination of 200 and 360 J DC shocks given by ordinary manual defibrillators or semiautomatic defibrillators. 120 of 127 ventricular fibrillation episodes were converted by three or less 360 J DC shocks delivered by a manual defibrillator. All 28 ventricular fibrillation episodes were converted by an average of 1.9 DC shocks when 360 J were delivered by a semiautomatic defibrillator. 139 of 152 ventricular fibrillation episodes were converted by three or fewer 200 J DC shocks and 52 of 53 by 2 x 200 J followed, if needed, by 1 x 360 J DC shock delivered by the same semiautomatic defibrillator. Three or fewer 360 J DC shocks seems completely adequate for conversion of most episodes of out-of-hospital ventricular fibrillation. There is no difference in the result of defibrillation by manual and semiautomatic defibrillators.

Bioelectric Energy Sources↗
PubMedDate not supplied

A skeletal muscle actuator for an artificial heart.

The authors developed a system to use skeletal muscle as an artificial heart actuator. This system consists of a flexible rod, sheath, crank, and cam to transmit the muscle power to a pusher plate pump and actuate it. The latissimus dorsi muscle was dissected at the lower ribs, and its end was connected with the flexible rod. The contraction of skeletal muscle was linearly transmitted, with the rod introduced inside the sheath, to the pump. The whole system was implanted in dogs (14-18 kg) and pump performance was evaluated with a mock circulatory system (preload = 10 mmHg, afterload = 75 mmHg). In these experiments, the pump output was maintained at 0.8 to 2.0 L/min (60 bpm) for 200 min, with a non-preconditioned muscle that was stimulated continuously. The output obtained was 2.5 mW/gram. Efficiency of this system was about 50% of the muscle power available. When the muscle was stimulated intermittently every 30 min, pump flow was maintained at > 0.8 L/min for 20 hr. Advantages of this system are: 1) the muscle power was linearly transmitted effectively, 2) this system could be installed with minimal surgery and without interruption in blood flow to the muscle, 3) the muscle is free from high intraventricular pressure that caused ischemia and, 4) the muscle can be set to the proper length in diastole to potentiate strong contractions.

Animals↗
PubMedDate not supplied

A single skeletal muscle powered ventricle that assists both systemic and pulmonary circulations.

Extraaortic counterpulsation using skeletal muscle powered ventricles (SMPVs) has been studied mainly for the purpose of assisting the systemic circulation. The purpose of this study was to investigate the possibility of assisting both the systemic and pulmonary circulations using a single SMPV. An SMPV that counterpulses the systemic circulation is placed beside the right atrium (RA) or the right ventricle (RV), the former after procedures such as a Fontan operation, and the latter in cases of biventricular failure. Because the SMPV dilates passively during cardiac systole, it is designed to press the RA or the RV directly from outside. This study is a preliminary report, and only the ability of a specially constructed SMPV to dilate was assessed. Using seven dogs with heart failure, the SMPV dilated with an internal pressure of 88 mmHg and 1.0 cm, while the volume inside increased by 10.8 ml. From these results, it is suggested that the SMPV has enough dilating power to press the RA or to assist the RV while counterpulsing the systemic circulation.

Animals↗
PubMedDate not supplied

Double chamber ventricular assist device with a roller screw linear actuator driven by left and right latissimus dorsi muscles.

A double chamber ventricular assist device (VAD) with a roller screw linear muscle actuator (RSLMA) driven by the left and right latissimus dorsi muscles was developed. The inflow port of each chamber was connected to form the compound inflow port, and the outflow ports were connected to form the compound outflow port. The advantages of this system include 1) the contraction of each muscle contributes to ejection from each ventricle into the common outflow port, thus doubling the net outflow; 2) through proper adjustment of muscle length, the preload to each muscle can be optimized to yield the maximum muscle force; 3) muscle can be stimulated at a lower rate to reduce fatigue and to optimize muscle performance; and 4) the compliance chamber needed in the implantable VAD system is not required with this system. In vitro evaluation in the mock loop with the human arm actuating the RSLMA revealed that the double chamber VAD can provide pump flows of 2-4 L/min against an afterload of 100 mmHg at a stimulation rate of 35-50 beats per minute. The power requirement for each muscle ranged from 2.5 to 3 W at a muscle stroke length of 4 cm. These results verify that the double chamber VAD with the RSLMA driven by the left and right latissimus dorsi muscles can meet the design requirements of a muscle driven VAD to assist the left heart.

Bioelectric Energy Sources↗
PubMedDate not supplied

Sustained skeletal muscle power for cardiac assist devices: implications of metabolic constraints.

A device to harness power from skeletal muscle contracting in a linear configuration is under development. This application requires a sustained level of power that is dependent upon muscle mechanics and metabolic properties. A biomechanical muscle model and a metabolic model constructed from experimental data were used to predict maximum power available in a sustainable region of loading and stimulation conditions. Latissimus dorsi (LD) of four goats were evaluated in vivo after a 10 week in situ conditioning protocol with an implanted Telectronics myostimulator. The LD insertion was reconnected to a hydraulic loading system, allowing isometric and isotonic contractions for biomechanical characterization. Metabolic utilization was measured by a thermister based myothermic technique. Brief fatigue tests of working isotonic contractions revealed stimulation conditions associated with sustained power. The results show metabolic utilization was dependent on contraction duration, rate, force, and stroke. The region of sustainable contractions was found for a range of durations of 0.1 to 0.6 sec and rates of 10 to 120 bpm. The boundary for the sustainable power region was well approximated by a constant value of metabolic utilization. A constant duty cycle (contraction to cycle duration ratio) also approximated the sustained power but differed by as much as 30% during the shorter contraction durations. The results demonstrate that a mechanical muscle model can predict maximum sustained power when the operating conditions are constrained to a sustainable range determined by a metabolic model. Furthermore, metabolic constraints influence the optimum conditions for sustained power needed in the design of skeletal muscle powered assist devices.

Animals↗