Biogas Reactor Research Articles

Evolution of the microbial community structure in biogas reactors inoculated with seeds from different origin

The aim of this work was to provide solid proofs regarding the achievement of “steady-state conditions”, which means that the performance of the anaerobic digester is representative of the applied environmental conditions. For this reason, we investigated how, starting from different inoculum sources (i.e., municipal wastewater treatment, bio-waste treatment, and agricultural waste biogas plant), the microbial community adapted to the operational parameters and led to stable biogas production in thermophilic digesters treating the same influent feedstock. The results revealed that the different system achieved similar process performance and microbial community structure after a period that was equal to four hydraulic retention times, approved by a constant pH of 7.89 ± 0.08, 7.92 ± 0.05 and 7.85 ± 0.08, respectively, and stable TAN concentration of 1500 mg/L. Moreover, it was found that the microbial composition of the inocula was a key factor for the speed of achieving stable process performance; thus, a pre-adapted to the influent feedstock inoculum can shorten the stabilization process. On the contrary, after long term reactor operation, the microbial structure was shaped according to the chemical composition of the influent feedstock. The results of the study can also be used as a guide in future researches on anaerobic degradation, particularly in determining the time interval of an experiment to reflect changes in the microbial community of anaerobic digester.

Strategies for recovery of imbalanced full-scale biogas reactor feeding with palm oil mill effluent.

BackgroundFull-scale biogas production from palm oil mill effluent (POME) was inhibited by low pH and highly volatile fatty acid (VFA) accumulation. Three strategies were investigated for recovering the anaerobic digestion (AD) imbalance on biogas production, namely the dilution method (tap water vs. biogas effluent), pH adjustment method (NaOH, NaHCO3, Ca(OH)2, oil palm ash), and bioaugmentation (active methane-producing sludge) method. The highly economical and feasible method was selected and validated in a full-scale application.ResultsThe inhibited sludge from a full-scale biogas reactor could be recovered within 30–36 days by employing various strategies. Dilution of the inhibited sludge with biogas effluent at a ratio of 8:2, pH adjustment with 0.14% w/v NaOH, and 8.0% w/v oil palm ash were considered to be more economically feasible than other strategies tested (dilution with tap water, or pH adjustment with 0.50% w/v Ca(OH)2, or 1.25% NaHCO3 and bioaugmentation) with a recovery time of 30–36 days. The recovered biogas reactor exhibited a 35–83% higher methane yield than self-recovery, with a significantly increased hydrolysis constant (kH) and specific methanogenic activity (SMA). The population of Clostridium sp., Bacillus sp., and Methanosarcina sp. increased in the recovered sludge. The imbalanced full-scale hybrid cover lagoon reactor was recovered within 15 days by dilution with biogas effluent at a ratio of 8:2 and a better result than the lab-scale test (36 days).ConclusionDilution of the inhibited sludge with biogas effluent could recover the imbalance of the full-scale POME-biogas reactor with economically feasible and high biogas production performance.

TEKNOLOGI PETERNAKAN TERPADU BERBASIS ENERGI BARU TERBARUKAN DI KABUPATEN TANGERANG

Tangerang Regency has the largest cattle farm in Banten Province. Animal husbandry business activities can have a positive impact, namely increasing community economic activities, as well as negative environmental impacts, namely livestock waste both solid and liquid waste. Partners in this activity are the Arafah Agro livestock business group and Barokah UMKM located in Pakulonan Barat Village, Kelapa Dua District, Tangerang Regency. So far, livestock waste management is only limited to being collected and then used for plant fertilizer. The technology to be implemented is a biogas reactor with a capacity of 12 m3, a chopper, a feed mixer, a solar powered water pump and a 500 liter water reservoir, and a PLTS with a capacity of 300 WP. The stages of its activities start from identifying the real conditions of partners related to the application of technology, designing and making technology systems, testing the technology systems that have been made, and conducting training and mentoring to partners in operating and utilizing technology that has been disseminated. The output of this activity is the use of cow biogascoture for cooking and lighting for cages, the installation of a solar powered water pump to suck water from the well into the reservoir, which can later be used for drinking and bathing cows and other stable operations, grass chopper and feed mixer. help provide high quality cow feed, thereby increasing cow productivity by up to 50%.

Turbulence Modeling in Side-Entry Stirred Tank Mixing Time Determination

Mixing is one of the critical processes in the industry. The stirred tank is one of the operating units commonly used in the mixing process. Several factors greatly influence the efficiency of the stirred tank, including the stirred-tank design, operating conditions, and working fluid properties. The side-entry stirred tank is widely applied in industry, among others; the processing of crude oil in the refinery industry, water-molasses mixing in the bioethanol industry, pulp stock chest in the pulp and paper industry, and anaerobic digester for biogas reactors. Mixing time is one of the critical parameters used in the design of the stirred tank. This research will model mixing time in a flat bottomed-cylindrical side-entry stirred tank with dimensions D = 40 cm and T = 40 cm using CFD ANSYS 18.2 by applying the Standard κ − ε (SKE) and Realizable κ − ε (RKE) turbulence models. The stirrer used is a three-blade marine propeller d = 4 cm which is an axial type impeller. The phenomenon of mixing in the side-entry stirred tank, qualitatively described through computational prediction results in the form of flow profiles and tracer density change contours locally. Moreover, quantitatively indicated by mixing time validated using experimental data carried out by the conductometry method. The computational prediction shows that the mixing time modeled using the SKE turbulence model shows a similarity level of 68.16%, while the RKE turbulence model shows 31.94%.

Calculation of the power of thermal energy consumed for heating the reactor of a bioenergy plant

The issues of calculating the power of thermal energy consumed for heating biomass in the reactor of a bioenergy plant are considered. Based on the Fourier heat equation, a solution for the axisymmetric cylindrical problem under boundary conditions of the first kind is obtained, and the power of additional heat sources in a cylindrical biogas reactor is calculated. The influence of the height of the bioreactor and the temperature difference of the biomass on the power consumption of an additional source of thermal energy is analyzed

Pembangunan Berkelanjutan Melalui Pengembangan Energi Berbasis Biogas (Studi pada Desa Sangun Ratu Kecamatan Pubian Kabupaten Lampung Tengah)

Energy is the most basic need for human. Energy utilized in various areas to support various activities in daily life. Energy that commonly used by community now is fossil energy such as petroleum, natural gas and coal. Those energy resouces are not renewable energy that might have depletion vulnerability of supplies. Therefore, in order to always be used by society in supporting their daily activities, energy must be developed. The development of energy can be done by using a renewable energy that abundantly available in Indonesia. One of renewable energies that can be developed in Indonesia is biogas energy that comes from livestock manure management in biogas reactors. One of regions in Indonesia that has done development of biogas energy is Sangun Ratu Village Pubian Subdistrict Central Lampung Regency. The purpose of this research is to describe the energy sustainability development and achievement of energy independence based on biogas in Sangun Ratu Village. The method of this research is descriptive qualitative with data collection techniques resourced from observation, documentation and depth interviews. The results of this study are described based on development management functions consisting of planning, mobilizing natural resources, budgeting, implementing development, coordinating, monitoring and evaluating and supervising sustainable development efforts which consist of aligning needs with natural resources, development of human resources, a triangle of partnerships and development with a long-term perspective. Sustainable development through the development of biogas-based energy in Sangun Ratu Village has been carried out in a sustainable manner from the end of 2013 to 2019. However, energy independence in Sangun Ratu Village has not been achieved because only 15.11% of the total community uses biogas-based independent energy to meet their daily energy needs. days such as cooking, petromax lighting and the use of bio-slurry (biogas waste).

ВИЗНАЧЕННЯ ЕНЕРГЕТИЧНО ЕФЕКТИВНОГО РІВНЯ ШВИДКОСТІ ПЕРЕМІШУВАЛЬНОГО ОРГАНУ ЕЛЕКТРОМЕХАНІЧНОЇ СИСТЕМИ

Purpose. Today, biomass fermentation in biogas plants is one of the most advanced, environmentally and economically viable solutions for energy production from waste. However, the process of anaerobic digestion of waste is long, so the main process of intensification is mixing. Analysis of well-known studies of domestic and foreign scientists indicates the urgency of reducing energy consumption for the mixing process. The aim of the study is to determine the energy-efficient speed of a paddle stirrer with blades set at an angle of 450 for small biogas reactors. Methodology. At the decision of the set tasks the general methods of physics, three-dimensional modeling, processing and visualization of the received results in the SolidWorks Flow Simulation and Wolfram Mathematica programs are applied. Results. Using 3D modeling, the influence of the stirrer speed on the picture of the distribution of the velocity vectors of the substrate flows in the biogas reactor was studied. Graphs of power consumption at the beginning of mixing for different stirrer speeds were obtained and analyzed, and the levels of energy consumed for mixing biomass during the start-up period and the whole mixing period were compared. A method for determining the energy efficient rotation speed of the stirring mechanism of the electromechanical system of biogas reactors is proposed. Practical value. The results can be used in the construction and modernization of biogas plants to reduce energy consumption of the substrate mixing process. Conclusion. Based on the research, it was concluded that for a paddle two-tier mixer with blades set at an angle of 450 energy-efficient speed, is 40 rpm. At this speed, careful and intensive mixing of the biomass is observed throughout the volume of the tank. The average velocity of flow vectors in the biomass volume is 0,273 m/s. The energy consumed per cycle of biomass mixing is 2471,3 J, and the percentage of energy consumed during the start-up period from the energy consumed during the entire mixing period is 0,62 %. References 19, figures 5.

The Role of Petrimonas mucosa ING2-E5AT in Mesophilic Biogas Reactor Systems as Deduced from Multiomics Analyses.

Members of the genera Proteiniphilum and Petrimonas were speculated to represent indicators reflecting process instability within anaerobic digestion (AD) microbiomes. Therefore, Petrimonas mucosa ING2-E5AT was isolated from a biogas reactor sample and sequenced on the PacBio RSII and Illumina MiSeq sequencers. Phylogenetic classification positioned the strain ING2-E5AT in close proximity to Fermentimonas and Proteiniphilum species (family Dysgonomonadaceae). ING2-E5AT encodes a number of genes for glycosyl-hydrolyses (GH) which are organized in Polysaccharide Utilization Loci (PUL) comprising tandem susCD-like genes for a TonB-dependent outer-membrane transporter and a cell surface glycan-binding protein. Different GHs encoded in PUL are involved in pectin degradation, reflecting a pronounced specialization of the ING2-E5AT PUL systems regarding the decomposition of this polysaccharide. Genes encoding enzymes participating in amino acids fermentation were also identified. Fragment recruitments with the ING2-E5AT genome as a template and publicly available metagenomes of AD microbiomes revealed that Petrimonas species are present in 146 out of 257 datasets supporting their importance in AD microbiomes. Metatranscriptome analyses of AD microbiomes uncovered active sugar and amino acid fermentation pathways for Petrimonas species. Likewise, screening of metaproteome datasets demonstrated expression of the Petrimonas PUL-specific component SusC providing further evidence that PUL play a central role for the lifestyle of Petrimonas species.

Biogas Fuel Utilization as Efforts to Overcome Household Economic Budget Problems in Rural Areas

Biogas is an important renewable energy as a superior substitute and is able to contribute to meeting the needs of household fuel stairs. The energy produced is used as a substitute for kerosene or LPG gas to meet daily needs such as cooking and others. Plant waste and livestock manure contain methane gas which has very good combustibility. Manure wastes such as cattle, horses, and others, are also found throughout Indonesia with different qualities. In general, the use of agricultural waste as a base for biogas is more difficult than livestock manure, because it takes longer to process the hydrolysis of cellulosic materials from agricultural waste and nutrients. One kilogram of manure releases about 208-268 liters of methane gas into the atmosphere. High nutritious livestock rations, resulting in low methane levels of manure. To describe comprehensively the usefulness of biogas utilization as a source of bioenergy fuel in an effort to overcome household economic budget problems in rural areas. Anearobic digestion process which is the basis and biogas reactor processed by the breakdown of organic matter by the activity of methanogenic bacteria in airless conditions. The materials required are a minimum of 3 culverts, a septi tank for the digester tank, and a large oil drum that can contain approximately 200 liters of material intended as methane gas. Another material, in the form of a metal pipe with a diameter of 2 cm, is useful as a gas discharge pipe and a biogas outlet valve. The pipe is used as a pipe for gas distribution from the digestive tank to the stove for cooking, lamps and others. The final result is a solid which functions as a plant organic fertilizer. There are also several compounds / materials that must be prevented because they can inhibit the breakdown process, such as Antibiotics and Disinfectants, and Heavy Metals. Please note that do not burn the gas that first formed, as it contains air in it and can explode. A few days after the biogas catcher drum is lifted upwards, it is advisable to open the tap and remove all the gas that has formed. To handle it with care and avoid fire around the biogas production unit. There is no need to release the gas formed and the gas is safe to use to meet household fuel needs. The best use of the biogas that has been collected from the biogas production unit is for cooking. Biogas technology is the right choice to convert agricultural and livestock waste to produce energy and fertilizer in order to obtain social benefits both in terms of economic, especially for households, especially in rural.

The effect of mixing rate and gas recirculation on biological CO2 methanation in two-stage CSTR systems

In-situ biological CO2 methanation (BM) in a biogas reactor by the addition of H2 is an attractive low-cost biogas upgrading process, as it does not require investment in a new reactor and can be incorporated into existing biogas plants. On the other hand, maintenance of stable reactor performance during in-situ BM is challenging due to factors such as high H2 partial pressure and CO2 depletion which may lead to an increase in pH. Thus, BM that uses two-serial connected continuous stirred tank reactors (CSTRs) could be an option. For such a process set-up, the second reactor acts as an upgrading reactor (UR) and a secondary CH4 producer for slow-degrading substrates such as straw and manure. In this study, improvement of the BM process was attempted by varying the mixing speed and gas recirculation to enhance hydrogen transfer to the liquid phase of the UR. The experiments showed that the mixing speed and gas recirculation had a significant effect on BM in CSTRs. CH4 production from BM was highest at 170 rpm, but the total CH4 production fell above 140 rpm due to reduced production of CH4 from the manure substrate. The CH4 production rate from CO2 and H2 conversion was further enhanced as the output gas was recirculated at 12.20 mL min−1. Further gas recirculation above 12.20 mL min−1 did not improve BM.

Integrating H2 injection and reactor mixing for low-cost H2 gas-liquid mass transfer in full-scale in situ biomethanation

Abstract In situ biomethanation combines Power-to-Gas and biogas upgrading by converting electricity-derived H2 and biogas-CO2 to CH4 in existing biogas reactors. Development of industrially relevant H2 injection technologies that facilitate high H2 gas-liquid mass transfer rates is key to advance the technology to commercial application. This study shows the potential of using a venturi-based biogas reactor mixing system for H2 injection into a full-scale biogas reactor by assessing the system’s H2 gas-liquid mass transfer capacity in short-term H2 injection experiments (1 h). H2 conversion rates were limited by H2 gas-liquid mass transfer at all experimental conditions and governed by H2 injection and biogas production rates. The highest experimental H2 conversion rate and H2 conversion efficiency amounted to 24.7 L H2 · m−3 · h-1 and 49 %, respectively. A predictive model suggests that the injection system can facilitate H2 conversion rates to a level equivalent to the stoichiometric conversion of 24–33% of the internally produced CO2 to CH4 in the full-scale reactor. The studied H2 injection technology hence provides a potential solution for low-cost partial in situ biogas upgrading, by using already installed mixing-capacity to facilitate H2 gas-liquid mass transfer.

A preliminary assessment of industrial symbiosis in Sodankylä

This study focuses on developing a possible architecture of planned industrial symbiosis in Sodankylä, Finland. The municipality of Sodankylä is considering the establishment of new businesses to boost the region's local economy. The preliminary assessment presented here evaluates some new markets, including combined heat and power plants, a biogas reactor, greenhouse farm, fish farm and several insect farms. These businesses should be able to fulfil the criteria of sustainability and circular economy. This study proposes an architecture where companies can quantify the value and the cost of material exchange. The combined life cycle cost and the net present value of symbiosis are estimated at €93 and €43 million respectively. The combined life cycle cost of waste management is calculated to be €6.40 million. The study's novelty is its projection of the quantified cost of bio-waste and recyclable waste of industries, highlighting the monetary value of industrial symbiosis where waste products can turn into industries' raw material. The value gained and cost reduced by such symbiosis is forecast at 14.65% and 6.8% respectively.

Обґрунтування створення електротепломеханічної системи перемішування та підігріву біомаси

To date, biomass fermentation in biogas plants is one of the most advanced, environmentally and economically viable solutions for energy production from waste. However, the process of anaerobic fermentation of waste is long, so one of the main ways to intensify biogas production is mixing and heating of biomass during fermentation. The article is devoted to the question of substantiation of creation of electrothermomechanical system for mixing and heating of biomass in a biogas reactor. The combination of two intensification processes in a combined system pays special attention to the energy efficiency of such a system, so the creation of the system requires in-depth study of heat fluctuations from speed and the presence of a contaminant layer on the heater surface and determine the optimal stirrer speed. The studies were performed for a cylindrical biogas reactor, assuming that the contaminant layer is evenly distributed on the surface of the blades and the shaft in which the electric heaters are installed. When determining the optimal frequency of biomass mixing, the criterion of optimality was taken to be the smallest value of the difference between the heat flux of the contaminated and uncontaminated surface of the heater. During the study it was found that at speed , the difference between the heat flux of the contaminated surface and uncontaminated is 40 %. At speed , the difference between the values is 26%. According to the selected optimality criterion, the optimal speed of the electrothermomechanical system taking into account the contaminant layer is in the range . The increase in heat flux from the stirring frequency is non-linear for both contaminated and non-contaminated heaters.

Abundance Tracking by Long-Read Nanopore Sequencing of Complex Microbial Communities in Samples from 20 Different Biogas/Wastewater Plants

Anaerobic digestion (AD) has long been critical technology for green energy, but the majority of the microorganisms involved are unknown and are currently not cultivable, which makes abundance tracking difficult. Developments in nanopore long-read sequencing make it a promising approach for monitoring microbial communities via metagenomic sequencing. For reliable monitoring of AD via long reads, we established a robust protocol for obtaining less fragmented, high-quality DNA, while preserving bacteria and archaea composition, for a broad range of different biogas reactors. Samples from 20 different biogas/wastewater reactors were investigated, and a median of 20.5 Gb sequencing data per nanopore flow cell was retrieved for each reactor using the developed DNA isolation protocol. The nanopore sequencing data were compared against Illumina sequencing data while using different taxonomic indices for read classifications. The Genome Taxonomy Database (GTDB) index allowed sufficient characterisation of the abundance of bacteria and archaea in biogas reactors with a dramatic improvement (1.8- to 13-fold increase) in taxonomic classification compared to the RefSeq index. Both technologies performed similarly in taxonomic read classification with a slight advantage for Illumina in regard to the total proportion of classified reads. However, nanopore sequencing data revealed a higher genus richness after classification. Metagenomic read classification via nanopore provides a promising approach to monitor the abundance of taxa present in a microbial AD community as an alternative to 16S ribosomal RNA studies or Illumina Sequencing.

Чисельне дослідження енергетичних втрат у навколишнє середовище для мезофільного режиму зброджування

The article is devoted to the study of energy losses of a biogas reactor into the environment during the fermentation of biomass in the mesophilic temperature regime. The article considers the influence of the presence of the insulating layer of the biogas reactor and the ambient temperature on the amount of energy losses and the required energy to recover these losses depending on the volume of the biogas reactor. The developed mathematical model allows to estimate the intensity of energy losses to the environment taking into account the amount of contamination of the inner wall of the biogas reactor, ambient temperature, average wind speed for the reactor location, surface area of the biogas reactor and its volume, material from which the biogas reactor is made, insulating layer and its material, mode of movement and frequency of biomass mixing. The following assumptions have been made for numerical studies: biomass fermentation takes place in the mesophilic temperature regime , biogas reactors with a volume of 50 to 200 liters, at ambient temperatures from to . It has been established that the heat loss to the environment for different volumes of biogas reactors, regardless of the ambient temperature and the presence or absence of an insulating layer, is not linear. Numerical research has shown that the use of an insulating layer of mineral wool with a thickness of 100 mm, depending on the volume of the biogas reactor and ambient temperature, reduces the amount of energy required to maintain the thermal regime by 55-63 times. Taking into account the amount of losses at the stage of design and manufacture of biogas reactors will reduce energy costs to maintain the required temperature, thereby increasing the profitability of the biogas plant.

Effect of Clinoptilolite and Halloysite Addition on Biogas Production and Microbial Community Structure during Anaerobic Digestion.

The study presents a comparison of the influence of a clinoptilolite-rich rock—zeolite (commonly used for improving anaerobic digestion processes)—and a highly porous clay mineral, halloysite (mainly used for gas purification), on the biogas production process. Batch experiments showed that the addition of each mineral increased the efficiency of mesophilic anaerobic digestion of both sewage sludge and maize silage. However, halloysite generated 15% higher biogas production during maize silage transformation. Halloysite also contributed to a much higher reduction of chemical oxygen demand for both substrates (by ~8% for maize silage and ~14% for sewage sludge) and a higher reduction of volatile solids and total ammonia for maize silage (by ~8% and ~4%, respectively). Metagenomic analysis of the microbial community structure showed that the addition of both mineral sorbents influenced the presence of key members of archaea and bacteria occurring in a well-operated biogas reactor. The significant difference between zeolite and halloysite is that the latter promoted the immobilization of key methanogenic archaea Methanolinea (belong to Methanomicrobia class). Based on this result, we postulate that halloysite could be useful not only as a sorbent for (bio)gas treatment methodologies but also as an agent for improving biogas production.

Metagenomic Study of Bacterial and Archaeal Populations during Anaerobic Digestion of Lignocellulosic Waste in Lab-scale Biogas Reactors

This study evaluated using 16S rDNA gene-based metagenomics technique the populations of bacteria and archaea in digestate samples from lab-scale anaerobic bioreactors digesting pretreated and untreated coconut husk fiber, pineapple floret and banana stem. Result of biodegradability experiment indicated high microbial activity in digestate (biogas slurry), with untreated banana stem having the highest total solids (TS) and volatile solids (VS) removal efficiencies of 78.3 % and 92.9 % respectively. Similarly, all pretreated substrates exhibited higher TS and VS losses with corresponding TS (77.8 %) and VS (87.2 %) removal efficiencies. This TS and VS removal rates signaled increased rate of organic matter decomposition with concomitant biogas productivity. Diversity comparisons performed between samples showed rich microbial diversity in untreated sample than the pretreated sample. Taxonomic composition revealed that, for untreated samples at the phylum level, the bacterial community was predominantly Firmicutes (relative abundance 97.0 %), with 0.30 % Actinobacteria and 0.10 % Proteobacteria. The genus Oxobacter (35.0 %), Clostridium (12.0 %) and Ethanoligenens (10.0 %) were ubiquitous and abundant in the untreated sample. The archaeal community was however dominated by the Euryarchaeota with one methanogenic order Methanomicrobiales, and a high abundance of the genera Thermacetogenium. For pretreated samples, at the phylum level, bacterial community was also dominated by Firmicutes (95.0 %), followed by Proteobacteria (1.02 %), Actinobacteria (0.18 %) and Tenericutes (0.06 %). The genus Clostridium (41.0 %), Ethanoligenens (29.0 %) and Lactobacillus (15.0 %) were also ubiquitous and abundant in the pretreated sample. Archaeal community was also dominated by Euryarchaeota with the two methanogenic orders Methanomicrobiales and Methanosarcinales dominating. The major microbial groups were hydrolyzing and fermenting populations. These findings revealed rich microbial assemblage and diversity among microbial communities in biogas digestate.

Saline fish wastewater in biogas plants - Biomethanation toxicity and safe use

Increasing marine land-based recirculating aquaculture systems (RAS) and stricter environmental regulations, pose new challenges to the aquaculture industry on how to treat and dispose saline fish wastewater. The fish wastewater could be incorporated into biogas reactors, but currently, the effects of salinity on the biomethanation process are poorly known. This study aimed to assess the toxicity of fish wastewater with different salinities on the biomethanation process and to propose optimum co-digestion scenarios for maximal methane potential and safe use in biogas plants. Results showed that, depending on salinity and organic content, it is possible to efficiently co-digest from 3.22 to 61.85% fish wastewater (v/v, wastewater/manure) and improve the maximum methane production rate from 2.72 to 61.85%, respectively compared to cow manure mono-digestion. Additionally, salinity was identified as the main inhibitor of biomethanation process with a half-maximal inhibitory concentration (IC50) of 4.37 g L−1, while sulphate reduction was identified as a secondary inhibitor.

Characterization and evaluation of biogas generation of Arba Minch Town slaughterhouse wastewater, Ethiopia

Abstract This study was carried out to characterize raw and treated Arba Minch town slaughterhouse wastewater and to assess its methane generation potential with lab-scale anaerobic batch reactors. The methane was collected by downward displacement of an alkaline water column. The methane generation potential of the slaughterhouse wastewater was 270.6 mL methane per gram of volatile solids at hydraulic retention time (HRT) of 20 days at 37 °C. The organic loading rate was 0.48 g and the organic matter removal efficiency of the reactor was COD (93.5%), BOD5 (88.5%), and TVS (94.7%). The result demonstrated that installation of a biogas reactor to treat slaughterhouse wastewater can recover methane, reduce pollutants and protect the environment. The result can be a demonstration for untreated slaughterhouse wastewaters in developing countries like Arba Minch Town to use anaerobic treatment and supplement their scarce energy options.

УТИЛІЗАЦІЯ СТІЧНИХ ФЕНОЛВМІСНИХ ВОД ГАЗОГЕНЕРАТОРНИХ УСТАНОВОК ШЛЯХОМ МЕТАНОВОЇ АНАЕРОБНОЇ ПЕРЕРОБКИ

Наведено результати експериментів з метанової анаеробної переробки конденсату сумісно з коров’ячим гноєм. Конденсат було отримано під час часткової газифікації березової тріски. Наведено вихід деревного вугілля та конденсату, сорбційні показники деревного вугілля, а саме питому внутрішню поверхню та йодне число. Визначено концентрацію фенольних сполук в конденсаті. Процес бродіння відбувався за мезофільної температури 35 °С. Незважаючи на інгібування процесу бродіння фенольними сполуками конденсату, що призвело до більш тривалої лаг-фази, має місце переробка органічних речовин конденсату в біогаз та інтенсифікація бродіння. Лаг-фаза під час бродіння конденсат-вмісних субстратів триває довше в 2,9–4,8 рази, ніж для контрольного субстрату, який не містив конденсату. Встановлено гранично допустиму концентрацію фенольних сполук в субстраті 103 мг/дм3, за якої має місце процес бродіння. Визначено вихід та склад біогазу, ступінь переробки органічної речовини та фенольних сполук. Кумулятивний вихід біогазу з одиниці об’єму субстрату на 40,3–58,6 % більший з конденсат-вмісних субстратів. Середня концентрація метану у виробленому біогазі на 9,6–13,6 % більша з конденсат-вмісних субстратів. Показано, що об’єм виробленого біогазу та вміст метану в біогазі підвищився за рахунок переробки фенольних сполук. При цьому деструкція фенольних сполук в конденсат-вмісних субстратах становила від 45,5 % до 80,3 %. На основі отриманих експериментальних результатів розроблена принципова схема для промислової реалізації наведеного способу перероблення конденсату. Це дасть змогу використати фізичну теплоту генераторного газу або для підтримування сталої температури всередині біогазового реактора, або для попереднього підігрівання субстрату. Органічні кислоти, розчинна смола та фенольні сполуки, що присутні в конденсаті переробляються в біогазовому реакторі для отримання біогазу. Бібл. 13, табл.1, рис. 2.