Improved organic matter biodegradation through pulsed H2 injections during in situ biomethanation

Molecular characterization of digestates from solid-state anaerobic digestion of pig slurry and straw using analytical pyrolysis

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 215:13-22 (2001) - doi:10.3354/meps215013 Effect of oxygen on the degradability of organic matter in subtidal and intertidal sediments of the North Sea area Birgit Dauwe*, Jack J. Middelburg**, Peter M. J. Herman Netherlands Institute of Ecology, Korringaweg 7, 4401 NT Yerseke, The Netherlands *Present address: RIKZ, Postbus 8039, 4330 EA Middelburg, The Netherlands **Corresponding author. E-mail: middelburg@cemo.nioo.knaw.nl ABSTRACT: The effect of oxygen on the degradation of sedimentary organic matter has been determined for 6 subtidal stations and 3 intertidal stations in the North Sea area. The stations were selected to cover a range of organic matter lability and sediment texture (and hence concentrations of organic matter). Slurry incubations revealed that at low mineralisation rates, aerobic mineralisation is significantly faster than anaerobic mineralisation, irrespective of the degree of lability of organic matter. A complementary incubation experiment with sediment rich in organic carbon mixed with varying proportions of organically poor sediments confirmed the enhanced aerobic mineralisation at low mineralisation levels. It is proposed that oxygen-enhanced degradation occurs at low mineralisation levels at which bacterial biomass production becomes limiting. KEY WORDS: Organic matter · Degradation · Oxygen · Sediments · North Sea · Intertidal Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 215. Online publication date: May 31, 2001 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2001 Inter-Research.

Degradation of organic matter from black shales and charcoal by the wood-rotting fungus Schizophyllum commune and release of DOC and heavy metals in the aqueous phase

The performance of bio-electrochemical anaerobic digester, applied with 0.3 V between anode and cathode, for sewage sludge was explored at different hydraulic retention times (HRTs) ranging from 20 to 5 days. The state variables including pH, alkalinity, VFA, and SCOD are quite stable and in suitable ranges for anaerobic digestion. At 20 days of HRT, the performance is considerably high in volatile solids (VS) reduction (70.5%), the specific methane production rate (407 mL L−1 d−1), and the methane content (76.9%) in biogas. The VS reduction and the methane content in biogas slightly deteriorated as the HRT decreased from 20 to 5 days, while the methane production rate increased to 1,339 mL L−1 d−1. The overall energy efficiencies for methane recovery are in the range of 69.1–98.7%, and the maximum energy efficiency appears at 10 days of HRT. These results showed that the bio-electrochemical anaerobic digestion system could obtain much higher VS reduction and energy recovery with shorter HRTs than the con...

Effect of seeding materials on organic matter degradation and microbial community succession during model organic waste composting

Anaerobic digestion or anaerobic digestion is a biological process of degradation of organic matter in an anaerobic environment. It involves the degradation and stabilization of complex organic matter by a consortium of micro-organisms leading to methane-rich biogas that can be used as an alternative energy to fossil fuels. In addition, the use of biogas allows for the preservation of the environment and the sustainable development of rural areas and landlocked regions, as well as the diversification of energy resources, but also contributes to the development of agriculture through the production of organic fertilizer. In 2018, Senegal was ranked as the 15th world exporter of cashew nuts with a production of around 18,000 tons per year according to a study by PADEC (Support Program for the Development of Casamance). Four regions mainly invest in it: Kolda, Ziguinchor, Sédhiou, and Fatick. However, in the natural region of Casamance ( Kolda, Ziguinchor, and Sédhiou), each year, after the cashew nut campaign, more than 342,000 tons of cashew apples, pressed or not, are rejected without any recovery, thus degrading in the environment. In addition, rice is traditionally grown in Casamance and in some Diola circles, it had become one of the criteria of wealth, which explains why it occupied most of the cultivated areas and each year thousands of tons of rice husk are burned for elimination/reduction without any recovery. These immense annual productions of waste, without any recovery, in a context dominated by a deficit in cooking and lighting energy constitutes a form of energy resilience and motivates us to study the co-digestion of the rice husk (with a report of C/N equal to 101.317) on cashew apple pulp (having a C/N ratio of 23.201 ). The study of the co-digestion of rice husk and apple pulp at the laboratory scale with the inoculum reveals, that the co-digestion with pH correction contains 39.40% methane and 51.50% carbon dioxide after 49 days of production and 64.04% methane (CH4) and 25.86% carbon dioxide (CO2) on the 96th day. For co-digestion without adjustment, production stopped on the 49th day with a production of 23.68% methane and 45.65% carbon dioxide.

Recent advances in anaerobic digestion has resulted in expansion of sustainable methods for use of waste as energy resources. Conventional methods prove to be uneconomical and environmentally impractical. Moreover, the microbial consortia in anaerobic digestion are temperature dependent and therefore requires investigations on temperature optimization. Therefore, the recent experimental study is being undertaken with the objective in order to assess the effect of temperature on anaerobic biodegradation of food wasted from a hostel campus. The effect of temperature on methane generation rate has also been investigated. The anaerobic digestion study under psychrophilic, mesophilic and thermophilic temperature conditions has been carried out and compared in order to assess the optimum methane production conditions. All the experimental study for anaerobic digestion of food waste has been carried out at optimum F/M (food to mass) ratio of 0.75. The cumulative highest methane production is observed to be 33, 50 and 65 mL of CH4 in reactor R1, R2 and R3 with initial food waste COD dosage of 100, 150 and 200 mg, respectively under mesophilic temperature conditions. The highest biochemical methane potential (BMP) value of 0.94, 0.95 and 0.93 gCH4-COD/gCOD fed in reactor R1, R2 and R3 respectively, under mesophilic temperature conditions. It been observed that for maximum methane generation rate constant of 0.62 d-1 were observed under thermophilic conditions thus has to be highly accelerative process but overall conversion of organic matter to methane is less as compared to mesophilic temperature conditions, this is because free ammonia concentration increases with increasing temperature, by influencing the equilibrium. However, mesophilic conditions provide a more stable environment for the anaerobic digestion process. This may be due to the fact that temperature fluctuations can disrupt the microbial activity and slow down the process, but mesophilic conditions provide a stable environment for the microorganisms to thrive. Therefore, the mesophilic temperature range provides a balance between high reaction rates, stability, and cost-effectiveness, making it the optimal temperature range for anaerobic digestion of food waste. The obtained results in present study will be helpful in implementing on full-scale anaerobic solid waste digesters for enhancing the methane generation under mesophilic temperature conditions with high organic matter removal. Also, under thermophilic conditions the energy requirement for heating proves to be uneconomical.

Pulp and paper (P&P) mills are currently one of the largest industrial water consumers and effluent generators worldwide. The biological effluent treatment processes currently in use generate a large volume of sludge (waste activated sludge – WAS), which requires great efforts and high costs to manage. An interesting option for sludge management is anaerobic digestion, a means of reducing sludge volume while generating renewable energy that can be used in the industrial processes. However, anaerobic technology needs to be improved, mainly due to the 30- to 40-day retention time required to digest pulp mill sludge in conventional anaerobic bioreactors. The thesis was structured in 3 chapters written as scientific papers. Chapter 1 presented a literature review about the potential of anaerobic digestion for sludge treatment in P&P mills and the application of pretreatment methods to enhance methane production, decrease the retention time and, ultimately, decrease the volume of the digesters. A case study examining the potential of integrating pretreatment and anaerobic sludge digestion in a Brazilian kraft pulp mill is also presented. The literature review resulted in 52 matches in which 16 articles were related to anaerobic digestion or co-digestion of P&P sludge without pretreatment and 20 articles had to do with anaerobic digestion of P&P sludge after pretreatment. A large discrepancy among the presented results made it difficult to assess the suitability of anaerobic digestion and the actual impacts of the sludge pretreatment on the viability of the system. Simulations were carried out using current data from a Brazilian kraft pulp mill and indicated the important role of sludge pretreatment in potential methane production. Chapter 2 aimed the application of thermal, thermal-alkaline and mechanical pretreatment methods in order to promote the solubilization of organic matter to enhance the anaerobic digestion. Chemical analyses showed an improvement in organic matter solubilization, with an increase greater than 1.2-fold for total COD, 7-fold for soluble COD and 4-fold for BOD 5 . In general, thermal-alkaline pretreatment showed the best results for all the evaluated parameters, with the advantage of requiring lower temperature and retention time when compared to thermal conditions. Chapter 3 aimed to evaluate the potential of methane production from the WAS of a bleached kraft pulp mill applying biochemical methane potential (BMP). After 30 days of testing, cumulative methane production increased from 90 mL CH 4 /gVS (raw sludge) to 181-194 mL CH 4 /gVS with thermally pretreated samples, and up to 203-204 mL CH 4 /gVS with samples which were pretreated using the thermo-alkaline technique. The pretreatment conditions of 175 °C for 15 min at pH 11 were sufficient to achieve both a high solubilization of WAS and a high methane production. The results showed that pretreatment could significantly enhance the anaerobic digestion of kraft pulp mill WAS, making this an attractive new option for sludge management in this sector. Keywords: Anaerobic digestion. Methane yield. Pretreatment. Pulp and paper mill. Secondary sludge.

Quantifying the degradation of organic matter in marine sediments: A review and synthesis

BackgroundBioelectrochemical systems have been considered a promising novel technology that shows an enhanced energy recovery, as well as generation of value-added products. A number of recent studies suggested that an enhancement of carbon conversion and biogas production can be achieved in an integrated system of microbial electrolysis cell (MEC) and anaerobic digestion (AD) for waste activated sludge (WAS). Microbial communities in integrated system would build a thorough energetic and metabolic interaction network regarding fermentation communities and electrode respiring communities. The characterization of integrated community structure and community shifts is not well understood, however, it starts to attract interest of scientists and engineers.ResultsIn the present work, energy recovery and WAS conversion are comprehensively affected by typical pretreated biosolid characteristics. We investigated the interaction of fermentation communities and electrode respiring communities in an integrated system of WAS fermentation and MEC for hydrogen recovery. A high energy recovery was achieved in the MECs feeding WAS fermentation liquid through alkaline pretreatment. Some anaerobes belonging to Firmicutes (Acetoanaerobium, Acetobacterium, and Fusibacter) showed synergistic relationship with exoelectrogens in the degradation of complex organic matter or recycling of MEC products (H2). High protein and polysaccharide but low fatty acid content led to the dominance of Proteiniclasticum and Parabacteroides, which showed a delayed contribution to the extracellular electron transport leading to a slow cascade utilization of WAS.ConclusionsEfficient pretreatment could supply more short-chain fatty acids and higher conductivities in the fermentative liquid, which facilitated mass transfer in anodic biofilm. The overall performance of WAS cascade utilization was substantially related to the microbial community structures, which in turn depended on the initial pretreatment to enhance WAS fermentation. It is worth noting that species in AD and MEC communities are able to build complex networks of interaction, which have not been sufficiently studied so far. It is therefore important to understand how choosing operational parameters can influence reactor performances. The current study highlights the interaction of fermentative bacteria and exoelectrogens in the integrated system.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-016-0493-2) contains supplementary material, which is available to authorized users.

Molecular-level characterization of biodegradable organic matter causing microbial regrowth in drinking water by non-target screening using Orbitrap mass spectrometry

A review on application of single and composite conductive additives for anaerobic digestion: Advances, challenges and prospects

Effect of nitrite on hydrolysis-acidification, biogas production and microbial community in semi-continuous two-phase anaerobic digestion of sewage sludge

The simultaneous fate of organic matter and 4 endocrine disruptors (3 polycyclic aromatic hydrocarbons (PAHs) (fluoranthene, benzo(b)fluoranthene, and benzo(a)pyrene) and nonylphenols (NP)) was studied during the anaerobic digestion followed by composting of sludge at lab-scale. Sludge organic matter was characterized, thanks to chemical fractionation and 3D fluorescence deciphering its accessibility and biodegradability. Total chemical oxygen demand (COD) removal was 41% and 56% during anaerobic digestion and composting, respectively. 3D fluorescence highlighted the quality changes of organic matter. During continuous anaerobic digestion, organic micropollutants' removal was 22 ± 14%, 6 ± 5%, 18 ± 9%, and 0% for fluoranthene, benzo(b)fluoranthene, benzo(a)pyrene, and nonylphenols, respectively. Discontinuous composting allowed to go further on the organic micropollutants' removal as 34 ± 8%, 31 ± 20%, 38 ± 10%, and 52 ± 6% of fluoranthene, benzo(b)fluoranthene, benzo(a)pyrene, and nonylphenols were dissipated, respectively. Moreover, the accessibility of PAH and NP expressed by their presence in the various sludge organic matter fractions and its evolution during both treatments was linked to both the quality evolution of the organic matter and the physicochemical properties of the PAH and NP; the presence in most accessible fractions explained the amount of PAH and NP dissipated.

Organic Matter Budgets for Streams: A Synthesis