Production Decomposition Research Articles

Mesophilic Process and Kinetics Studies of Selected Biomolecules as Potential Enhancers of Biomethanization of Cow Dung in an Anaerobic Tubular Batch Reactor

Mesophilic biogas production and substrate decomposition is one of the significant limiting steps in biogas generation. The rate of generation and quality often affect the viability of biogas systems. This study assessed the potential for biogas process catalysis using powdered Sorghum bicolor L., Zea mays, and Pennisetum glaucum. The kinetics and biogas generation processes were studied. Experiments were conducted in 1 m3 tubular batch reactors, where batches were dosed with various organic biomolecules. Results show that the use of P. glaucum L. and S. bicolor L. reduced the biogas retention times significantly. Biogas generation commenced after the first day for digesters fed with S. bicolor L. and P. glaucum L. while one with Z. mays and control occurred on day two. The rate of biomethanation and methane content were enhanced. S. bicolor L. led to the highest methane content. Findings reveal that locally available organic biomolecules improved biogas quality and quantity.

Effect of Nitrogen Addition on Soil Microbial Functional Gene Abundance and Community Diversity in Permafrost Peatland.

Nitrogen is the limiting nutrient for plant growth in peatland ecosystems. Nitrogen addition significantly affects the plant biomass, diversity and community structure in peatlands. However, the response of belowground microbe to nitrogen addition in peatland ecosystems remains largely unknown. In this study, we performed long-term nitrogen addition experiments in a permafrost peatland in the northwest slope of the Great Xing’an Mountains. The four nitrogen addition treatments applied in this study were 0 g N·m−2·year−1 (CK), 6 g N·m−2·year−1 (N1), 12 g N·m−2·year−1 (N2), and 24 g N·m−2·year−1 (N3). Effects of nitrogen addition over a period of nine growing seasons on the soil microbial abundance and community diversity in permafrost peatland were analyzed. The results showed that the abundances of soil bacteria, fungi, archaea, nitrogen-cycling genes (nifH and b-amoA), and mcrA increased in N1, N2, and N3 treatments compared to CK. This indicated that nitrogen addition promoted microbial decomposition of soil organic matter, nitrogen fixation, ammonia oxidation, nitrification, and methane production. Moreover, nitrogen addition altered the microbial community composition. At the phylum level, the relative abundance of Proteobacteria increased significantly in the N2 treatment. However, the relative abundances of Actinobacteria and Verrucifera in the N2 treatment and Patescibacteria in the N1 treatment decreased significantly. The heatmap showed that the dominant order composition of soil bacteria in N1, N2, and N3 treatments and the CK treatment were different, and the dominant order composition of soil fungi in CK and N3 treatments were different. The N1 treatment showed a significant increase in the Ace and Chao indices of bacteria and Simpson index of fungi. The outcomes of this study suggest that nitrogen addition altered the soil microbial abundance, community structure, and diversity, affecting the soil microbial carbon and nitrogen cycling in permafrost peatland. The results are helpful to understand the microbial mediation on ecological processes in response to N addition.

Hydrogen Production and Heat Transfer Distributions of Ammonia Decomposition in an Atmospheric Pressure Plasma Plate Reactor

Hydrogen Production and Heat Transfer Distributions of Ammonia Decomposition in an Atmospheric Pressure Plasma Plate Reactor

A Feasibility Study on Effect of Food Waste Leachate Additions in the Full-Scale Waste Leachate Treatment Facility after the African Swine Fever Outbreak in South Korea

Due to the ban on the use of food waste as wet swine feed after the outbreak of African swine fever (ASF), 2900 tons/day of food waste and 1083 tons/day of food waste leachate were additionally generated. As an alternative treatment method for food waste leachate, the input of food waste leachate on weekends (5% of food waste leachate inflow, 100 tons/day) and its increased input (merge ratio 21.7%, 227.01 tons/day → 27.8%, 453.71 tons/day) into the digesters operated in a public sewage treatment plant were investigated. Additionally, the feasibility of the method was evaluated by analyzing the operation parameters, evaluating the operation efficiency, and identifying other environmental effects on the sewage treatment plant. In the case of input on weekends, the organic matter decomposition rate and gas production rate decreased by 8.0% and 9.5%, respectively, although the input on weekends was judged to be feasible, considering that the inflow into the WWTP increased by up to 206% due to the long-term (7 weeks) monsoon. In the case of the increased input of food waste leachate, the organic matter decomposition and gas production rates increased by 2.5% and 4.8%, respectively, compared with before the increased input. The results of this study confirmed that the additional input of food waste leachate into existing biogasification facilities is feasible. When performed in a stable manner, the use of food waste for anaerobic digestion is considered an appropriate alternative treatment method to wet feed. This will lead to technological and industrial development.

Catalyzed H2O2 decomposition over iron oxides and oxyhydroxides: Insights from oxygen production and organic degradation

Iron minerals, such as iron oxides and iron oxyhydroxides, are the main influential soil components in catalyzed hydrogen peroxide propagation (CHP). Due to their dual effects on H2O2 activation to produce reactive oxygen species (ROS) and invalid consumption to produce oxygen, the intrinsic reactivity of iron minerals toward H2O2 decomposition requires comprehensive investigations. Herein, six iron minerals (hematite, magnetite, maghemite, goethite, feroxyhyte, and ferrihydrite) for H2O2 decomposition were investigated by a combination of normalized kinetic rate constants of H2O2 decomposition (NkH2O2), O2 production (NkO2), benzoic acid degradation (NkBA), and hexachloroethane degradation (NkHCA) over the surface area of each mineral. The results indicate H2O2 decomposition over iron minerals is a surface-related heterogeneous process. Hematite and goethite are the most promising minerals for environmental cleanup in terms of ROS production, because their H2O2 utilization efficiency for benzoic acid (BA) degradation (0.138 and 0.024 mol BA/mol H2O2 for hematite and goethite, respectively) are highest among the six iron minerals. Magnetite and maghemite are highly active for both H2O2 decomposition and O2 production at neutral and basic pHs. The presence of organic compounds suppresses O2 production by more than 60%, which favors H2O2 utilization. Ferrihydrite and feroxyhyte are considered as the problematic mineral for CHP due to that the two minerals acquire a high O2 production and negligible ROS generation at all pHs. The results of this study provide new insights to increase the understandings of H2O2-iron mineral systems and guide the application of iron minerals in chemical oxidation technologies.

Phosphorus supply affects long-term carbon accumulation in mid-latitude ombrotrophic peatlands

Ombrotrophic peatlands are a globally important carbon store and depend on atmospheric nutrient deposition to balance ecosystem productivity and microbial decomposition. Human activities have increased atmospheric nutrient fluxes, but the impacts of variability in phosphorus supply on carbon sequestration in ombrotrophic peatlands are unclear. Here, we synthesise phosphorus, nitrogen and carbon stoichiometric data in the surface and deeper layers of mid-latitude Sphagnum-dominated peatlands across Europe, North America and Chile. We find that long-term elevated phosphorus deposition and accumulation strongly correlate with increased organic matter decomposition and lower carbon accumulation in the catotelm. This contrasts with literature that finds short-term increases in phosphorus supply stimulates rapid carbon accumulation, suggesting phosphorus deposition imposes a threshold effect on net ecosystem productivity and carbon burial. We suggest phosphorus supply is an important, but overlooked, factor governing long-term carbon storage in ombrotrophic peatlands, raising the prospect that post-industrial phosphorus deposition may degrade this carbon sink.

The interplay of labour, land, intermediate consumption and output: a decomposition of the agricultural labour productivity for the Baltic States

This article proposes a decomposition approach for the agricultural labour productivity change that takes into account the land-to-labour ratio, intermediate consumption intensity and intermediate consumption productivity. The case of the three Baltic States (Estonia, Latvia, Lithuania) is considered which is interesting in the light of the European Union (E.U.) expansion and the structural change taking place in those countries. In addition, Poland, Germany and Denmark are included in the analysis as benchmark countries. To quantify the drivers of the agricultural labour change in the countries considered, the Index Decomposition Analysis (I.D.A.) is applied. The analysis proceeds in two directions: first, the cumulative change in the agricultural labour productivity over 1998–2018 is decomposed for each country under analysis; second, differences in the agricultural labour productivity for each country vis-à-vis Denmark (the highest productivity country) are decomposed. The results offer important policy implications as the intermediate consumption intensity appears as the critical factor that needs to be addressed via the support payments.

Estimation of fine root production, mortality, and decomposition by using two core methods and litterbag experiments in a mangrove forest

AbstractMangrove forests are characterized by high rates of carbon sequestration, with much of this carbon being derived from fine roots. In this study, we sought to estimate the dynamics of the fine (<2 mm) and small (≥2 mm) roots of Kandelia obovata, one of the mangrove forest species found on Okinawa Island, southern Japan, and to evaluate annual root production considering root decomposition estimated using root litterbags. To estimate root production and mortality, we applied two approaches, sequential soil core sampling and ingrowth core methods. We found that annual root production determined by sequential soil core sampling was 3.2 times higher than that estimated by ingrowth core methods. The annual production of fine roots (545 and 294 g m−2 year−1 for sequential soil core sampling and ingrowth core methods, respectively) was higher than that of small roots (536 and 44 g m−2 year−1 for sequential soil core sampling and ingrowth core methods, respectively). The results obtained using sequential soil core sampling indicated a high proportion of fine root necromass to total fine root mass (81%), most of which comprised very fine roots (<0.5 mm). We also established that the decomposition ratio of fine roots was lower than that of small roots. Collectively, our observations indicate that the slow rate of decomposition and high rate of production of fine roots contribute significantly to the accumulation of fine root necromass, particularly that of very fine roots, in the mangrove forest.

Sargassum Differentially Shapes the Microbiota Composition and Diversity at Coastal Tide Sites and Inland Storage Sites on Caribbean Islands.

Rafts of drifting pelagic Sargassum that are circulating across the Atlantic Ocean are complex ecosystems composed of a large number of associated species. Upon massive stranding, they lead to various socio-environmental issues including the inflow of contaminants and human health concerns. In this study, we used metabarcoding approaches to examine the differences in both the eukaryotic- and prokaryotic-associated communities from Sargassum present in two islands of the Lesser Antilles, namely Guadeloupe and Martinique. We detected significant differences in microbial community structure and composition between landing Sargassum, the surrounding seawater, and Sargassum from inland storage sites. In total we identified 22,214 prokaryotic and 17,679 eukaryotic OTUs. Among them, functional prediction analyses revealed a number of prokaryotes that might contribute to organic matter decomposition, nitrogen cycling and gas production, including sulfate-reducing bacteria at coastal landing sites, and methanogenic archaea at inland storage sites. We also found that Metazoan was the most abundant group in Sargassum samples, with nematode clades that presented exclusive or specific richness and abundance patterns depending on their Sargassum substrate. Together, these molecular inventories of the micro- and meiofauna communities provide baseline information for further characterization of trophic interactions, algal organic matter decomposition and nutrient transfers at coastal and inland storage sites.

Growth-enhanced salmon modify stream ecosystem functioning.

Use of fast-growing domesticated and/or genetically modified strains of fish is becoming increasingly common in aquaculture, increasing the likelihood of deliberate or accidental introductions into the wild. To date, their ecological impacts on ecosystems remain to be quantified. Here, using a controlled phenotype manipulation by implanting growth hormone in juvenile Atlantic salmon (Salmo salar), we found that growth-enhanced fish display changes in several phenotypic traits known to be important for ecosystem functioning, such as habitat use, morphology and excretion rate. Furthermore, these phenotypic changes were associated with significant impacts on the invertebrate community and key stream ecosystem functions such as primary production and leaf-litter decomposition. These findings provide novel evidence that introductions of growth-enhanced fish into the wild can affect the functioning of natural ecosystems and represent a form of intraspecific invasion. Consequently, environmental impact assessments of growth-enhanced organisms need to explicitly consider ecosystem-level effects.

A framework linking farming resilience with productivity: empirical validation from Poland in times of crises

Farming sectors’ resilience has been built over decades with the aid of policies and institutions. However, its actual standing can be assessed in times of crises when farms have to overcome particular challenges. We use a large-scale farming sectors dataset FADN spanning 2006–2015 in which two major economic crises occurred—the global economic crisis of 2008 and the Russian embargo of 2014—to exemplify our approach to resilience’s assessment based on the Polish farming sectors. We introduce a distinction between “potential resilience” versus “revealed resilience” where the former is assessed based on resilience capacities (robustness, adaptability and transformability), while the latter is assessed based on the observed decomposition of total factor productivity (TFP) changes in response to the adverse economic shocks. Hence, the proposed framework directly links productivity with the two types of resilience. We applied the Färe-Primont method of TFP decomposition, into technological change and various types of efficiency changes and a detailed farm survey to distinguish between the drivers of technological changes in each farming sector such as specific innovations and ecosystem services. Our findings show that farms differ in their revealed resilience both among the sectors and between two different shock events. Only field crop farms and granivores farms (pig and poultry) maintained their resilience to both crises, staying robust and/or adaptable. The former had the most productive technology and were leaders in applying innovations while the latter were second best in innovations and fairly good in their application of ecosystem-based services into their technology. Other farm types failed to be resilient to the first crisis but proved robust during the second. The outcomes of the study have implications for sustainability oriented policies.

Energy recovery behavior of low-frequency electric heating assisted depressurization in Class 1 hydrate deposits

Class 1 hydrate deposits are characterized by a free gas layer (FGL) underneath the hydrate-bearing layer (HBL) and are considered as the most potential target for commercial exploitation. To improve the contribution of hydrate decomposition to gas production, an efficient development method of low-frequency electric heating assisted depressurization under five-point well pattern is proposed for Class 1 hydrate deposits, which involves the implementation of electric heating after a certain period of depressurization. Based on the geological data of Messoyakha gas field, the numerical simulation model is established. Then the energy recovery behaviors under single depressurization and the proposed method are investigated through numerical simulation approach. Results indicate that the gas production rate of Class 1 hydrate deposits is extremely high at the initial stage of depressurization, but decreases sharply due to insufficient reservoir energy. After the implementation of electric heating, hydrate decomposition and gas production are significantly improved, and a considerable energy efficiency ratio is obtained. Under the same heat input, the linear decreasing voltage mode exhibits better production performance than the constant voltage mode, and can avoid the continuous high temperature near the wellbore to damage the electrode elements, which has greater potential for the exploitation of hydrate deposits. At the end of 10 years of production, a cylindrical hydrate decomposition zone with a radius of about 40 m is formed around each production well. The simulation results confirm the feasibility of the proposed method and provide new insights for enhancing gas recovery in Class 1 hydrate deposits.

Decomposition and measurement of the rebound effect: The case of energy efficiency improvements in Spain

The rebound effect caused by energy efficiency improvements demands greater attention from energy policymakers as it represents an important obstacle to energy consumption reduction measures. Despite the emerging literature about the rebound effect, no studies to date have managed to break down it. To do so, this study introduces the disruptive innovation of replacing the Logarithmic Mean Divisia Index method used in previous literature with Structural Decomposition Analysis. Based on Input-Output tables, a re-spending model allows us to assess the Indirect Rebound Effect for 14 productive sectors. Finally, Structural Decomposition Analysis enables us to determine the Economy-Wide Rebound Effect caused by energy efficiency improvements. As far as we are aware, no other study to date has done so. Spain is used as a case study for the 2000–2014 period. Major findings indicate that total rebound effect varies from nearly to 10% to around 50%. The part of rebound explained by Direct rebound effect is around 10%. Indirect rebound effect shows values between 1.2% and 1.8%. Finally, Economic wide rebound effect varies from −4.51% to around 40% but without showing a clear trend for the period considered. The novelty of this study is that it attempts to break the overall rebound effect down to the direct, indirect, and economic wide rebound effect by combining the Cobb-Douglas production function and decomposition techniques.

Enhanced Fluid Dynamics in 3D Monolithic Reactors to Improve the Chemical Performance: Experimental and Numerical Investigation

Three-dimensional (3D) Fe/SiC monoliths with parallel interconnected channels and different cell geometries (square, troncoconical, and triangular) were manufactured by robocasting and used as catalytic reactors in hydroxylation of phenol using hydrogen peroxide to produce dihydroxybenzenes; the reaction was performed at Cphenol,0 = 0.33 M, Cphenol,0:CH2O2,0 = 1:1 M, WR = 3.7 g, T = 80–90 °C, and τ = 0–254 gcat·h·L–1 with water as a solvent. The values of the apparent kinetic rate constants demonstrated the superior performance of the triangular cell monoliths for hydrogen peroxide decomposition, phenol hydroxylation, and dihydroxybenzene production reactions. A computational fluid dynamic model was validated with the experimental results. It demonstrated that the triangular cell monoliths, with a lower channel hydraulic diameter and not-facing interconnections, provided a higher internal macrotortuosity that induced an oscillating flow of the liquid phase inside the channels, leading to an additional transverse flow between adjacent parallel channels. This behavior, not observed in the other two geometries, resulted in a better overall performance.

Effect of Laser Land Levelling on Paddy-Wheat and Cotton-Wheat Cropping Pattern in Haryana

The study has quantified and compared the effect of laser land levelling technology with conventional land levelling in paddy-wheat and cotton-wheat cropping pattern in Karnal and Sirsa district of Haryana state, respectively. Using Bisaliah decomposition model (1977) improved technology and change in input use to enhance productivity under laser land levelling has been assessed. Decomposition of total productivity highlighted that in Karnal district, out of total incremental change in productivity, 8.38 and 5.36 per cent change was contributed only due to change in technology and rest was due to input use in paddy-wheat, respectively. Similarly, in Sirsa district, out of total change in productivity 5.4 and 4.87 per cent change contributed only due to enhancement in technology while rest was due to input use in cotton-wheat cropping pattern, respectively. Further study highlighted that water as well as fertilizer use efficiency was most influenced by use of laser land levelling technology. On the account of results of study, it was concluded that laser land levelling is an effective scale neutral resource conservation technology which has immense potential to cure low water use efficiency and improve fertilizer use in most prevalent cropping patterns (i.e. paddy-wheat as well as cotton) of Haryana state.

Does low birth rate affect China’s total factor productivity?

This study uses the DEA-Malmquist method to measure total factor productivity by employing the provincial panel data from 1998 to 2017 in China and constructing a panel data model to test the relationship between birth rate and human capital and the influence of labour in different age groups on total factor productivity. It was found that the increase in the birth rate has a significantly negative effect on human capital accumulation, while the effect of the birth rate on human capital shows an inverted ‘U’ shape. That is, when birth rate decreases, human capital increases, and when birth rate increases, human capital decreases. Thus, too low or too high birth rates will reduce human capital. Ultimately, human capital accumulation will significantly promote the growth and decomposition of total factor productivity. The effect of the labour age structure on total factor productivity also shows an inverted ‘U’ shape. Labour between 40 and 49 years old contributes the most to the promotion of total factor productivity. Eventually, due to the low birth rates, the proportion of 50-59 years old will keep at high level. Therefore, total factor productivity will decline significantly.

Microplastics in freshwater sediments: Effects on benthic invertebrate communities and ecosystem functioning assessed in artificial streams

The high levels of microplastics (MPs) found in freshwaters, particularly in riverine sediments, may impose a threat to the macroinvertebrate communities with possible consequences at ecosystem-level. The present study aimed to assess the effects of a mixture of different sizes of polyethylene microplastics (PE-MPs) on the composition and structure of macroinvertebrate communities and key-functions, such as primary production and leaf litter decomposition. MPs were mixed in the sediment at three different concentrations (0.1, 1, and 10 g kg-1) already found in freshwater sediments to enhance the relevance of the work. After eight days of exposure to PE-MPs, the observed changes in macroinvertebrate community structure were mostly due to the reduction in the abundance of deposit-feeders and grazers that were reduced by ca 31-50% and 34-39%, in the two highest MPs concentrations respectively, in comparison with the control treatment after 8 days of exposure. MPs internal concentrations were detected only in organisms exposed to plastic particles within artificial streams with chironomids and mayflies presenting higher MPs internal levels (average of 115 particles/individual found in chironomids, 166/individual for Baetis sp. and 415 particles/individual for Ephemerella sp.) suggesting higher ingestion of plastic microparticles. Nevertheless, the alterations in the community structure did not translate into impairments in the functional endpoints analysed, leaf litter decomposition and primary production, that were expected due to possible sub-lethal effects (e.g., feeding inhibition) on detritivores and grazers.This study represents one of the few assessments of MPs effects on freshwater benthic macroinvertebrate community structure and the first that simultaneously considered ecosystem-level functional endpoints. Further research combining different microplastics and longer exposure periods are needed to raise knowledge on potential ecological consequences of MPs to freshwaters.

The Efficiency of Indian Banks: A DEA, Malmquist and SFA Analysis with Bad Output.

In the recent years, the burgeoning non-performing assets (NPAs) have become a matter of concern and scrutiny in India as the surge in NPAs impinge on the credit services of the banks, make the banks vulnerable to external shocks, leave them with less cushion in case of idiosyncratic shocks and thus, leading to the abrasion of their productive capital. In this backdrop, some very normative questions become inevitable. How has the technical efficiency of the banks in India changed over time especially after the asset quality review, 2016? How does undesirable output like non-performing assets (NPA) impact the technical efficiency of banks in India? Does technical efficiency have anything to do with the ownership of banks? These are some of the questions we endeavour to answer through our study by employing three cornerstone methodologies namely DEA, Malmquist productivity index and SFA in the banking sector for the period 2014–2020.The results obtained from employing DEA and SFA both points toward the heterogeneity in the technical efficiency of public sector banks and private sectors banks operating in India. The results obtained from DEA are majorly three-fold. Firstly, private sector banks have fared better than the public sector banks, while the SFA scores show that the public sector ownership promotes efficiency. Secondly, the technical efficiency of public sector banks has consistently been falling from 2014 to 2017 only to rise in the later years, evidence corroborated by the SFA scores also. This trend is in line with the slew of measures adopted by the government and RBI like AQR and mergers of banks subsequently. Although according to the Malmquist productivity decomposition results, we find that productivity of banks have been falling for the period 2014–2020. Thirdly, the non-performing assets are detrimental for the efficiency of the banks. Like DEA, the SFA results also shows the presence of technical inefficiency in the Indian banking sector and a similar trend in the technical efficiency wherein the scores decline from 2014 through 2017 and then they rise subsequently.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40953-021-00247-x.

Trend, instability and decomposition analysis of coffee production in Ethiopia (1993–2019)

Measuring the trends of growth and variability in agricultural production is important to understand how outputs change over time. Ethiopia is the largest producer of coffee in Africa and the fifth in the world. Despite the abundant opportunities and continuous efforts made to enhance its production, it is often said that the productivity of Ethiopian coffee remains far below its potential. Yet, empirical data on the status of coffee production over time in Ethiopia is scant. We, thus, analyzed the trend, instability, and decomposition of coffee production in Ethiopia for three periods, i.e., the entire period (1993–2019), the pre-Agricultural Growth Program period (1993–2010), and the Agricultural Growth Program period (2011–2019). In all three periods, harvested area and production showed an increasing trend while productivity showed a cyclical decreasing trend. The compound growth rates of harvested area (8.14%) and production (6.68%) in the 1993–2019 period were positive and significant at 1% level, whereas that of productivity (-0.45%) was not significant. Similarly, the compound growth rates of harvested area and production during pre-AGP (6.02 and 6.06%) and AGP (6.43 and 3.57%) were positive, but only significant during AGP, and that of productivity in both pre-AGP and AGP (0.19 and -1.6%) were not significant. Productivity was, however, more stable than harvested area and production during the entire and pre-AGP periods, while harvested area and production were more stable in AGP than in the other two periods. Besides, the harvested area effect on production differentials was substantial in all three periods, while productivity and productivity-harvested area interaction effects declined production during the entire and AGP periods. Overall, the results demonstrate that to enhance and sustain coffee production in Ethiopia, using improved varieties and agronomic practices can be a better option than expanding the cultivation area since land is scarce and fixed in supply.

Structural change decomposition of productivity without share weights

Structural change is important driver of productivity. Existing decompositions of structural change rely heavily on the share weights of firms. Ideally, one would need a complete census of all firms to calculate the share weights. However, empirical data are often less than ideal. Another limitation of the structural change decompositions is that existing firms that switch from one industry to another are mixed with startups and bankrupt firms. To address both these limitations, we develop an alternative productivity decomposition of structural change that avoids the use of share weights, which can be useful whenever the share weights are problematic or unavailable. Our decomposition also takes the product switch explicitly into account and applies to both the level and percentage change of productivity. Application to Finnish agriculture illustrates the proposed approach.