- Lactic acid bacteria modulate organic acid production during early stages of food waste composting. [Journal Article]
- STSci Total Environ 2019 Jun 08; 687:341-347
- Lactic acid bacteria are observed during early stages of almost all food waste composting. Among them, 2 types of lactic acid bacteria, Pediococcus (homofermentative lactic acid bacterium) and Weisse…
Lactic acid bacteria are observed during early stages of almost all food waste composting. Among them, 2 types of lactic acid bacteria, Pediococcus (homofermentative lactic acid bacterium) and Weissella (heterofermentative lactic acid bacterium) have been often reported. In this study, the roles of these 2 types of lactic acid bacteria in the composting were tried to elucidate. It has been pointed out that Pediococcus accelerates the composting process by producing lactic acid which prevented acetic acid generation, thus activating indigenous composting microorganisms. On the other hand, this study elucidated that Weissella produced acetic acid of 20 mg g-1 DS, which is harmful to composting microorganisms, resulting in the inhibition of vigorous organic matter degradation. When these 2 coexist in the starting material, whether the composting succceeds or not depends on the ratio of these 2 lactic acid bacteria. If Pediococcus and Weissella ratio was higher than 101.5, acetic acid level was almost 3 times lower than that observed in the composting with their lower ratios of 1 and 10-1, probably because of the interaction of Pediococcus and Weissella resulting in the suppression of Weissella activity, and thus composting was accelerated.
- Geotextile clogging at different stages of municipal solid waste landfills co-disposed with bottom ash. [Journal Article]
- STSci Total Environ 2019 Jun 08; 687:161-167
- Co-disposal of bottom ash (BA) with municipal solid waste (MSW) in landfills is a common way for BA management. However, BA co-disposal in MSW landfills may accelerate geotextile clogging and reduce …
Co-disposal of bottom ash (BA) with municipal solid waste (MSW) in landfills is a common way for BA management. However, BA co-disposal in MSW landfills may accelerate geotextile clogging and reduce the performance of leachate collection system. This study compared geotextile clogging in a simulated MSW landfill leachate (MSWL) and a BA co-disposed landfill leachate (BAL) at different landfill stages. Geotextile clogging test was conducted using the MSWL and BAL taken from the simulated landfills on the 10th, 80th, 140th and 200th day, respectively. The results demonstrated that geotextile clogging varied with landfill age, due to the change of leachate characteristics. The mass of clogging material in geotextiles with BAL increased from 0.45 g to 2.74 g, which was 43.87%-63.73% greater than those with MSWL. The formation of biofilm was the main contributor for the geotextile clogging. At the same stage, the amount of biofilm formed on geotextile in different leachate was comparable. However, the amounts of CaCO3 precipitation on geotextile in BAL were 3.85-10.44 times of those in MSW leachate. The pH of leachate played a critical role in CaCO3 precipitation. The microbial analysis revealed that the co-disposal of the BA greatly influenced the microbial community diversity and structure.
- Understanding synergies and trade-offs between water and energy production at landfill sites. [Journal Article]
- STSci Total Environ 2019 Jun 06; 687:152-160
- Landfills provide the most commonly used waste disposal solution. They are designed to reduce the risk of environmental or public health hazards due to waste disposal, and are used for waste manageme…
Landfills provide the most commonly used waste disposal solution. They are designed to reduce the risk of environmental or public health hazards due to waste disposal, and are used for waste management purposes in many places around the world. Depending on the design of the site and recovery methods, landfill sites can work as a potential reserve of energy and water for society. Landfill biogas is a source of renewable energy, and surface water can be collected in a retention pond. Although researchers broadly agree on the importance of incorporating the concept of the energy and water nexus into policy strategies and decision-making, the lack of studies focused on how governance methods that incorporate energy-water linkages at landfill sites can improve the provision of these two essential services has hindered progress in this direction. This study analyzes the links between water-energy nexus at a restored landfill site in Taipei City, Taiwan. The study tracks leachate and methane production at the site over the time periods when the landfill was actively receiving waste and after its closure and since its restoration. The results of model simulation of leachate yield and methane collection under different conditions show that energy and water production changed considerably during the time span under consideration. We identified an increasing trend of water and energy production in the landfill operation phase and a decreasing trend of water and energy production in the landfill restoration phase. In addition, we also identify a synergy between energy generation and water volume during the operation phase, and show that no trade-offs between energy generation and water volume were observed during any of the phases studied. These observations imply that greater water volumes will always lead to greater energy production, which can help inform future landfill design and governance practices.
- Changes of heavy metal fractions during co-composting of agricultural waste and river sediment with inoculation of Phanerochaete chrysosporium. [Journal Article]
- JHJ Hazard Mater 2019 Jun 11; 378:120757
- The effects of Phanerochaete chrysosporium on the bioavailability of multiple heavy metals (Pb, Cd, Cu, and Zn) in river sediments were investigated by co-composting with the agricultural waste. The …
The effects of Phanerochaete chrysosporium on the bioavailability of multiple heavy metals (Pb, Cd, Cu, and Zn) in river sediments were investigated by co-composting with the agricultural waste. The results showed that the Phanerochaete chrysosporium inoculation can greatly enhance the passivation on Cu, Pb and Cd during 60 days co-composting. The effects in the three metals followed the order: Cu > Cd > Pb. There were no differences for Zn whether inoculation with P. chrysosporium or not. Redundancy analysis (RDA) implied that more than 4/5 of the variation of all fractions data for all heavy metals was explained by all significant canonical axes. P. chrysosporium can change the significant parameters for each metal and enhance the explanatory power of RDA model. The inoculation can strengthen the effect of OM (organic matter) on the bioavailability of heavy metals, but weaken the contribution of pH.
- Oxidation resistance of nanoscale zero-valent iron supported on exhausted coffee grounds. [Journal Article]
- CChemosphere 2019 Jun 10; 234:179-186
- In this study, nanoscale zero-valent iron (NZVI) was supported by exhausted coffee grounds. Exhausted coffee grounds are a crucial waste generated in enormous amounts. Since supported nanoscale parti…
In this study, nanoscale zero-valent iron (NZVI) was supported by exhausted coffee grounds. Exhausted coffee grounds are a crucial waste generated in enormous amounts. Since supported nanoscale particles have a lower free energy than bare particles, oxidation resistance of supported NZVI on coffee grounds (NZVI-Coffee ground) is postulated. The main aim of this study was to ascertain the enhanced oxidation resistance of NZVI-Coffee ground. Synthesized materials were dried and stored in the air at temperatures of 4, 20, and 35 °C. Changes in the surface characteristics and cadmium removal efficiency of the supported NZVI were investigated. Fourier transformation infrared spectroscopy and X-ray photoelectron spectroscopy showed that supported NZVI underwent less oxidation compared to bare NZVI. Cadmium removal efficiencies of supported NZVI did not deteriorate with age, while those of bare NZVI decreased by 9.5 ± 0.1, 13.0 ± 0.1, and 18.3 ± 0.2% compared to their initial removal efficiencies when stored 8 weeks at 4, 20, and 35 °C, respectively. This is because the surface free energy of the NZVI decreased via strong interaction with the functional groups of the coffee grounds. According to the results, exhausted coffee grounds are an effective supporting material for NZVI to enhance its storage stability.
- Pyrolysis kinetics and synergistic effect in co-pyrolysis of Samanea saman seeds and polyethylene terephthalate using thermogravimetric analyser. [Journal Article]
- BTBioresour Technol 2019 Jun 06; 289:121608
- This work deals with co-pyrolysis of polyethylene terephthalate (PET) with Samanea saman seeds (SS) to understand the kinetics and synergistic effects between two different feedstocks. SS and PET wer…
This work deals with co-pyrolysis of polyethylene terephthalate (PET) with Samanea saman seeds (SS) to understand the kinetics and synergistic effects between two different feedstocks. SS and PET were blended in different ratios (1:1, 3:1 and 5:1) and iso-conversional models such as Kissinger-Akahira-Sunose (KAS), Friedman method (FM), Starink (ST), Ozawa-Flynn-Wall method (OFW), and Coats-Redfern method (CR) were used to calculate the kinetic parameters. Results substantiate assumed hypothesis that blending of SS and PET at 3:1 provided higher synergistic effect and RMS value, which in turn indicated maximum formation of hot volatiles during pyrolysis. Kinetic analysis confirmed that individual SS and PET required higher activation energy while blended SS and PET at 3:1 ratio required lower activation energy to start the reaction. The thermodynamic and kinetic analysis confirmed that biomass had complex reaction kinetics which depends on reaction rate as well as its order.
- Microbial communities in co-digestion of food wastes and wastewater biosolids. [Journal Article]
- BTBioresour Technol 2019 May 30; 289:121580
- The effect of food waste (FW) co-digestion with wastewater biosolids (WWB) on microbial communities was investigated through running thirteen lab-scale digesters for 100 days at different operational…
The effect of food waste (FW) co-digestion with wastewater biosolids (WWB) on microbial communities was investigated through running thirteen lab-scale digesters for 100 days at different operational conditions i.e. organic loading rates (2 and 4 kgCOD/m3·day), feed types (WWB and FW), and FW content (10%, 90%, 100%). Compared with mono-digestion of WWB, FW co-digestion enhanced biogas production by 13% and COD degradation rates by up to 101%. Among fermentative bacteria/acetogens, Syntrophomonas was the dominant genus in FW digesters in contrast to the dominance of Clostridium in WWB digesters. The predominant methanogen was Methanosarcina in FW digesters in contrast to Methanosaeta in WWB digesters. COD degradation rates and methane yields were well correlated with Bacteroidetes population. Methane production rate was well correlated with Clostridium for FW digesters, with syntrophs for WWB digesters, and with aceticlastic methanogens for both digesters. Synergism was associated with hydrolytic bacteria, Clostridium, Syntrophomonas, syntrophs, Methanosarcina, and Methanobacterium.
- A study on catalytic co-pyrolysis of kitchen waste with tire waste over ZSM-5 using TG-FTIR and Py-GC/MS. [Journal Article]
- BTBioresour Technol 2019 May 31; 289:121585
- Co-pyrolysis characteristics of kitchen waste (KW) with tire waste (TW) were studied by TGA-FTIR and Py-GC/MS. The kinetic parameters were calculated by Ozawa-Flynn-Wall (OFW) and the Kissinger-Akahi…
Co-pyrolysis characteristics of kitchen waste (KW) with tire waste (TW) were studied by TGA-FTIR and Py-GC/MS. The kinetic parameters were calculated by Ozawa-Flynn-Wall (OFW) and the Kissinger-Akahira-Sunose (KAS) methods. TGA-FTIR results indicated that CO2, CO, NO, NH3, SO2, CH and CC groups were the main gases released from the pyrolysis process, finding that a certain coupling synergistic interaction occurred between KW and TW. Co-pyrolysis of KW and TW displayed positive synergy in pyrolysis kinetics, especially at the ratio of 5:5 whose apparent activation energy declined 16.78% (by FWO) and 17.54% (by KAS). The Py-GC/MS results found that co-pyrolysis could increase the total peak area of volatile matters (10.92-15.34%). Moreover, co-pyrolysis could increase hydrocarbons (especially for olefins (13.25-37.42%)) and inhibit non-hydrocarbon compounds (about 63%) of volatile products. In brief, co-pyrolysis of KW and TW could be a potential way for improving quality of pyrolysis oil.
- Impact of climate change on the American lobster (Homarus americanus): Physiological responses to combined exposure of elevated temperature and pCO2. [Journal Article]
- CBComp Biochem Physiol A Mol Integr Physiol 2019 Jun 14
- The physiological consequences of exposing marine organisms to predicted future ocean scenarios, i.e. simultaneous increase in temperature and pCO2, have only recently begun to be investigated. Adult…
The physiological consequences of exposing marine organisms to predicted future ocean scenarios, i.e. simultaneous increase in temperature and pCO2, have only recently begun to be investigated. Adult American lobster (Homarus americanus) were exposed to either current (16 °C, 47 Pa pCO2, pH 8.10) or predicted year 2300 (20 °C, 948 Pa pCO2, pH 7.10) ocean parameters for 14-16 days prior to assessing physiological changes in their hemolymph parameters as well as whole animal ammonia excretion and resting metabolic rate. Acclimation of lobster simultaneously to elevated pCO2 and temperature induced a prolonged respiratory acidosis that was only partially compensated for via accumulation of extracellular HCO3- and ammonia. Furthermore, acclimated animals possessed significantly higher ammonia excretion and oxygen consumption rates suggesting that future ocean scenarios may increase basal energetic demands on H. americanus. Enzyme activity related to protein metabolism (glutamine dehydrogenase, alanine aminotransferase, and aspartate aminotransferase) in hepatopancreas and muscle tissue were unaltered in future ocean scenario exposed animals; however, muscular citrate synthase activity was reduced suggesting that, while protein catabolism may be unchanged, the net energetic output of muscle may be compromised in future scenarios. Overall, H. americanus acclimated to ocean conditions predicted for the year 2300 appear to be incapable of fully compensating against climate change-related acid-base challenges and experience an increase in metabolic waste excretion and oxygen consumption. Combining our study with past literature on H. americanus suggests that the whole lifecycle from larvae to adult stages is at risk of severe growth, survival and reproductive consequences due to climate change.
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- Ordering Patterns and Costs of Specialized Laboratory Testing by Hospitalists and House Staff in Hospitalized Patients With HIV at a County Hospital: An Opportunity for Diagnostic Stewardship. [Journal Article]
- OFOpen Forum Infect Dis 2019; 6(6):ofz158
- CONCLUSIONS: Many tests ordered in HIV-positive inpatients do not have indications, representing a substantial source of health care waste and cost and potentially leading to inappropriate treatment. Opportunities exist to decrease waste through education of trainees and hospitalists and through implementation of diagnostic stewardship via the electronic medical record.