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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Treatment of slaughterhouse blood waste using pilot scale two-stage anaerobic digesters for biogas production

Anaerobic digestion (AD) is an attractive technology for treatment of slaughterhouse blood waste for energy recovery to offset energy used in the slaughterhouse. However, no studies have been conducted at the pilot or full scales using such waste streams as the primary substrate. In this study, three 197-L pilot scale two-stage AD systems, with or without bamboo biocarriers, treating poultry blood waste were evaluated at two organic loading rates (OLRs) (low = 0.4 and high = 0.7 g COD L -1 day -1 ) under mesophilic condition (26 ± 2 °C) for 260 days. Biocarriers were added to immobilize the microflora and increase cell residence time in the digesters. Results show that the system with biocarriers had methane yield of 192 mL g -1 COD added and COD removal of 32.4% at the high OLR, and methane yield of 384 mL g -1 COD added and COD removal of 68.5% at the low OLR, which were significantly higher than those of the system without biocarriers (used as control). Methanobrevibacter and Methanobacterium beijingense were the dominant archaea in the system using biocarriers. It is estimated that 39.7–41.4 kJ can be recovered from the treatment of blood waste from each kg of slaughtered livestock weight using the two-stage AD system.

42 ENGINEERING↗
DOE OSTI2018

Monitoring of microbial communities in anaerobic digestion sludge for biogas optimisation

Highlights: • Characterisation of microbial communities by cloning, pyrosequencing and T-RFLP. • T-RFLP is most suitable as monitoring method but lacks taxonomic information. • Existing in silico tools unable to identify T-RFs in T-RFLP analysis of AD sludge. • This study developed a combined approach to assign taxonomy to database of T-RFs. • Combined approach is a reliable and economical way to monitor microbial consortia. - Abstract: This study characterised and compared the microbial communities of anaerobic digestion (AD) sludge using three different methods – (1) Clone library; (2) Pyrosequencing; and (3) Terminal restriction fragment length polymorphism (T-RFLP). Although high-throughput sequencing techniques are becoming increasingly popular and affordable, the reliance of such techniques for frequent monitoring of microbial communities may be a financial burden for some. Furthermore, the depth of microbial analysis revealed by high-throughput sequencing may not be required for monitoring purposes. This study aims to develop a rapid, reliable and economical approach for the monitoring of microbial communities in AD sludge. A combined approach where genetic information of sequences from clone library was used to assign phylogeny to T-RFs determined experimentally was developed in this study. In order to assess the effectiveness of the combined approach, microbial communities determined by the combined approach was compared to that characterised by pyrosequencing. Results showed that both pyrosequencing and clone library methods determined the dominant bacteria phyla to be Proteobacteria, Firmicutes, Bacteroidetes, and Thermotogae. Both methods also found that sludge A and B were predominantly dominated by acetogenic methanogens followed by hydrogenotrophic methanogens. The number of OTUs detected by T-RFLP was significantly lesser than that detected by the clone library. In this study, T-RFLP analysis identified majority of the dominant species of the archaeal consortia. However, many of the more highly diverse bacteria consortia were missed. Nevertheless, the combined approach developed in this study where clone sequences from the clone library were used to assign phylogeny to T-RFs determined experimentally managed to accurately predict the same dominant microbial groups for both sludge A and sludge B, as compared to the pyrosequencing results. Results showed that the combined approach of clone library and T-RFLP accurately predicted the dominant microbial groups and thus is a reliable and more economical way to monitor the evolution of microbial systems in AD sludge.

09 BIOMASS FUELS↗
DOE OSTI2022

Long term performance of pilot methanogenic digester filled with seashell wastes treating slaughterhouse wastes: Biogas production and environmental impact

High ammonia and organic acids contents of decomposed slaughterhouse waste (SHW) often result in the severe inhibition or even failure of the anaerobic digestion (AD). The two-stage AD system can alleviate the ammonia inhibition; however, addition of alkali is often needed to maintain the neutral condition. In this study, seashell wastes containing high percentage of calcium carbonate (CaCO 3 ) were for the first time added in a pilot scale methanogenic digester treating chicken blood waste to retain the microorganisms and provide pH buffers for the substrate. A long-duration performance of this digester was conducted for 400 days under different organic loading rates (OLRs). The results show that methane yields of the digester were 244.8 and 224.9 mL g –1 COD added at OLR of 0.4 and 0.6 g COD L –1 d –1 , respectively, higher than the results of previous studies treating the similar feedstock. An AD system treating blood wastes of a typical poultry slaughterhouse was also proposed for which energy balance and carbon footprint analyses were conducted. The energy production of 0.35 MJ kg –1 blood and carbon emissions reduction of 0.05 kg CO 2 -eq kg –1 blood can be achieved from treating blood waste of the broiler chicken. Finally, this study reveals that using seashell wastes in an AD treating SHW can facilitate the reuse of aquaculture wastes and improve the sustainability of meat industry.

09 BIOMASS FUELS↗
DOE OSTI2026

Comparative life-cycle assessments and techno-economic analysis of renewable natural gas production pathways from biogas

Renewable natural gas (RNG) offers a promising pathway for decarbonizing hard-to-abate sectors. This study shows that, relative to conventional upgrading technologies (i.e., membrane separation and pressure swing adsorption), the catalytic methanation reaction (CMR) at water resource recovery facilities doubles RNG output. When consuming lowcarbon hydrogen, the CMR reduces operational energy use and global warming potential. Techno-economic analysis indicates that the CMR is not yet competitive but will become viable if hydrogen reaches $1/kg. Heat integration and hydrogen cost are key drivers of overall performance.

03 NATURAL GAS↗