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Showing papers on "Biogas published in 1990"


Journal ArticleDOI
TL;DR: In this article, the authors conducted about 30 experiments and obtained some 900 individual measurements of trace gases emitted from rice fields and biogas generators around Chengdu in the Sichuan Province of China.

91 citations


Journal ArticleDOI
TL;DR: In this article, the start-up of the dry anaerobic batch digestion by the BIOCEL-concept of the organic fraction of municipal solid waste (MSW) is unbalanced when a methanogenic inoculum (digested sewage sludge) is added to a total solids concentration of 35%.

76 citations


Journal ArticleDOI
TL;DR: In this paper, the authors developed a new device that is precise, inexpensive, easily constructed and capable of functioning autonomously for long periods of time in an anaerobic digester.

72 citations


Journal ArticleDOI
TL;DR: The narrow range among all experiments of CO2 desorption efficiencies achieved in air stripping the recycle stream (35‐60% CO2 removal) suggests that comparable methane enrichment‐may be achieved with unpressurized single‐stage digestion using greater recycle rates.
Abstract: A major cost consideration in the use of anaerobic digestion to convert biomass and waste to utility-grade gas is the expense of separating CO(2) from the product gas. Anaerobic digestion has a number of inherent properties that can be exploited to increase the methane content of the gas directly produced by the digester, the most important of which is the high solubility of CO(2)(40-60 times that of methane) in water under digestion conditions. The methane enrichment concept examined in this study involved the recirculation of a liquid stream from the digester through a CO(2) desorption process and the return of the liquid stream back to the digester for absorption of additional CO(2) produced by the conversion of organic materials. A steady-state equilibrium model predicted that a digester gas methane content exceeding 94% could be achieved with this scheme using modest recirculation rates provided a desorption process could be designed to achieve a 60+% CO(2) removal efficiency in the degassing of the liquid recycle stream. Using fixed-film laboratory digesters operated on synthetic feedstocks, the technique of methane enrichment was tested under pressurized and unpressurized conditions. A 93 + 2% methane gas stream was produced from a volatile-acid-fed bench-scale digester simulating the methanogenic stage of two-phase digestion under conditions of (1) a pH swing achieved without caustic addition that allowed digestion at pH 7. 5 and air stripping at pH 6. 5-7. 0, (2) digester pressurization to 30 psig, and (3) a recycle rate of 0. 33 L/L reactor/day. Significant but lower levels of methane enrichment were achieved with the single-stage digester at the low experimental recycle rate. However, the narrow range among all experiments of CO(2) desorption efficiencies achieved in air stripping the recycle stream (35-60% CO(2) removal) suggests that comparable methane enrichment-may be achieved with unpressurized single-stage digestion using greater recycle rates. A materials balance analysis of data from an unpressurized, single-stage digester employing no chemical addition and using laboratory degassing efficiencies indicated that 94% methane could be produced at recycle rates of less than 1. 4 L/L reactor/day with a methane loss of less than 2%.

56 citations


Journal ArticleDOI
TL;DR: From November 1985 to May 1988, experiments with anaerobic treatment of wastewater from a fish cannery were carried out at the Water Quality Institute at Aarhus, Denmark to determine the biogas yield from COD reduction and to show the efficiency of the reactor as a function of the following operation parameters.

48 citations


Journal ArticleDOI
TL;DR: Various spent agro-residues obtained after cultivation of the edible mushroom Pleurotus sajor-caju were used in anaerobic digestors for production of biogas, which resulted in increasedBiogas production by the spent residues due to the increased susceptibility to digestion and more favourable C/N ratio of the residues.
Abstract: Various spent agro-residues obtained after cultivation of the edible mushroom Pleurotus sajor-caju were used in anaerobic digestors for production of biogas. The changes that take place in the residues during bioconversion were quantified in terms of composition of cellulose, hemicellulose, lignin, carbon and nitrogen. These “mycostraws” resulted in increased biogas production over the untreated ones, which varied from 21.5% in the case of spent bagasse to 38.8% in the case of spent paddy straw. The increased biogas generation by the spent residues seems to be due to the increased susceptibility to digestion and more favourable C/N ratio of the residues.

47 citations


Journal ArticleDOI
TL;DR: Analysis of the inhibition pattern of methane/biogas production has shown that UAN displayed a moderate half-kill dose in the range of 10 millimole and demonstrated a high sensitivity exponent, suggesting potential for a sudden failure response of an anaerobic system subjected to an increasing ammonia concentration in the reactor.
Abstract: The effects of ammonia on mesophilic digestion of acetate, propionate, acetate-propionate mixture, and lactate were studied in batch serum bottles. The un-ionized ammonia nitrogen (UAN) affected the acetate-utilizing microorganisms in the acclimated mixed cultures to a greater extent than propionate-utilizing bacteria or other trophic groups. The inhibitory effects were less severe in batch reactors supplemented with sulfate, pointing to an antagonistic action of the sulfate-reducing bacteria. Analysis of the inhibition pattern of methane/biogas production has shown that UAN displayed a moderate half-kill dose in the range of 10 millimole and demonstrated a high sensitivity exponent. The latter suggests potential for a sudden failure response of an anaerobic system subjected to an increasing ammonia concentration in the reactor.

46 citations


Journal ArticleDOI
TL;DR: Novel, laboratory-scale, high solids reactors operated under mesophilic conditions were used to study the anaerobic fermentation of processed municipal solid waste to methane, and recovery of theAnaerobic consortium, following dilution of inhibitory high Solids levels, was swift.
Abstract: Novel, laboratory-scale, high solids reactors operated under mesophilic conditions were used to study the anaerobic fermentation of processed municipal solid waste (MSW) to methane. The anaerobic digestion consortium was introduced to high solids levels through gradual adaptation. The maximum sludge solids level for stable anaerobic fermentation performance was identified as approximately 36% wt/wt. Recovery of the anaerobic consortium, following dilution of inhibitory high solids levels, was swift. Reactor mixing requirements were also studied. No significant difference in fermentation performance was observed between agitator speeds of 1 and 25 rpm. Preliminary fermentation performance tests showed that solids loading rates as high as 9.5 g VS (volatile solids) feed/L sludge.d, at 32% solids within the reactor, were possible. Under these conditions, operation was stable with an average pH of 7.8–8.0, total volatile fatty acid pools of <20 mM, and a biogas composition of 55%–60% methane.

36 citations


Journal ArticleDOI
TL;DR: It was found that an iron concentration of up to 5 650 mg/l, which is well in excess of previously reported toxicity levels, had no inhibitory effects on anaerobic digestion, with the exception of a decrease in biogas production.
Abstract: The ability of methanogenic bacteria to adapt to high concentrations of iron was investigated using a 9l Upflow Anaerobic Sludge Blanket (UASB) reactor fed semi-continuously with a synthetic waste containing glucose as the organic carbon source. It was found that an iron concentration of up to 5 650 mg/l, which is well in excess of previously reported toxicity levels, had no inhibitory effects on anaerobic digestion, with the exception of a decrease in biogas production. The iron precipitated out and accumulated in the sludge bed of the digester, resulting in very low concentrations of iron in the digester effluent.

35 citations


Journal ArticleDOI
TL;DR: In this paper, anaerobic digestion of effluent from a petrochemical plant producing terephthalic acid has been tested using two Upflow Anaerobic Sludge Blanket (USAB) reactors.
Abstract: Anaerobic digestion of effluent from a petrochemical plant producing terephthalic acid has been tested using two Upflow Anaerobic Sludge Blanket (USAB) reactors. The reactors were seeded with two different inocula: one from an anaerobic stabilization pond receiving wasted sludge from the aerobic treatment plant of the petrochemical industry (reactor A); the other was an anaerobically adapted activated sludge from a municipal wastewater treatment plant (reactor B). At the beginning of the experiment, reactor A attained higher COD removal efficiencies and biogas production, but both reactors reached the same performances after 7 mo operation. The efficiencies in COD removal were low. At a 3 d hydraulic retention time (HRT), reactor A was loaded at 2.6 kg COD/m3 d and reactor B at 2.2 kg COD/m3 d. COD removals were 46.4 and 43.9% for reactor A and B, respectively. In view of these results, the UASB reactor does not appear as the most suitable treatment process for this kind of effluent.

34 citations


Journal ArticleDOI
TL;DR: The potentiality of some plant wastes plus poultry litter as feedstocks for biogas production was determined in this article, where some wastes could substitute for cowdung when dung was in short supply.

Journal ArticleDOI
01 Jan 1990-Biomass
TL;DR: In this paper, the composition and anaerobic digestibility of products from two different municipal solid waste processing operations were compared, with cellulose constituting approximately 50% by weight.

Journal ArticleDOI
01 Jan 1990-Biomass
TL;DR: The feasibility of producing biogas by anaerobic digestion of a nitrophilic algae biomass obtained from the highly eutrophicated Venice Lagoon has been investigated and sulphides were formed during digestion but did not appear to cause inhibition or result in a reduction in gas yield.

Journal ArticleDOI
TL;DR: In this article, an 11-month study was conducted to compare the performances of three laboratory plastic medium upflow anaerobic filters operating at 12.5°C, 21°C and 30°C.

Journal ArticleDOI
TL;DR: In this article, the anaerobic digestion of paper mill sludge containing a high amount of inorganic matter was studied and the degradation efficiency of neutral detergent fiber was investigated at various loading rates and solid retention times.


Journal ArticleDOI
01 Jan 1990-Biomass
TL;DR: In this paper, the authors report on the authors' efforts to improve the small farm community welfare in Kenya by promoting biogas technology, which not only guarantees a reliable, renewable energy source, but also provides other benefits, such as cleaner household environments, better working conditions for housewives, etc.

Journal ArticleDOI
TL;DR: In this article, the production of biogas from mixtures of fresh and partially-decomposed Ageratum with cattle dung was studied in batch digesters at 30 ± 1°C.

Journal ArticleDOI
TL;DR: In this article, the anaerobic digestion of the organic fraction of municipal solid waste sorted by plant was investigated in a 3 m3 stirred digester, operating under mesophilic conditions.

Journal ArticleDOI
01 Jan 1990-Biomass
TL;DR: In this paper, a generalized procedure for quantifying the benefits of household biogas plants is presented, in which the sensitivity of the procedure to the uncertainty in input prices is reduced through the assumption of incremental benefits from the Biogas plant.

Journal ArticleDOI
TL;DR: An integrated system forBiogas production from mango-processing wastes and utilization of biogas effluent for production of major carp Rohu, (Labeo rohita) and common carp was studied.

Journal ArticleDOI
01 Jan 1990-Biomass
TL;DR: In this article, the effect of sulfate removal from molasses wastewater on anaerobic digestion was studied using two reactors, one with an active biomass and the other without attached biomass.

Book ChapterDOI
01 Jan 1990
TL;DR: In this article, the effects of temperature, pH, loading rates and adaptation phenomena have been studied in a bioreactor with ammonium concentrations in an anaerobic degradation of nitrogen-rich substrate and, as in the case of manure, added via the urine.
Abstract: Nitrogen-rich organic materials, such as swine and poultry manure, slaughterhouse and fish industry waste, etc., generally produce smaller amounts of biogas than similar substrates with lower nitrogen contents. In addition, methane formation rates are lower during fermentation of the nitrogen-rich materials (McCarty & McKinney, 1961; van Velsen, 1979; 1981; Wiegant, 1986). These differences seem to be due to the fact that ammonium, which at high concentrations inhibits methane formation (van Velsen, 1979; 1981; Wiegant, 1986), is formed during the anaerobic degradation of nitrogen-rich substrate and, as in the case of manure, is also added via the urine (cf Fig. 1). Elevated ammonium concentrations can prolong the period necessary for starting up a bioreactor. In addition, longer retention times are necessary in order to obtain a given reduction in COD in nitrogen-rich material as compared with organic matter with a lower nitrogen content. Research within this field has thus far been performed mainly in laboratory reactor systems, where effects of temperature, pH, loading rates and adaptation phenomena have been studied. Present know-ledge within this field is briefly summarized below.

Journal ArticleDOI
Hang-Sik Shin1, Byeong Cheon Paik1
TL;DR: Higher superficial flow rate increased COD removal efficiency, sludge retainment, and methane content in biogas not only in the start-up period but also at high volumetric loading rates.
Abstract: The efficient operation of UASB reactors treating complex soluble wastewater containing high protein and lipid content was attempted by mixing in different modes. Higher superficial flow rate increased COD removal efficiency, sludge retainment, and methane content in biogas not only in the start-up period but also at high volumetric loading rates. However, formation of sludge particles in larger size was hindered by increased upflow liquid velocity.


Journal ArticleDOI
TL;DR: Lebrato et al. as mentioned in this paper used a semicontinuous anaerobic digester for the treatment of wastewater from a cheese factory in a bath at 35 + 1'C, and magnetically stirred at 100 rpm.
Abstract: Lebrato, J., Perez-Rodriguez, J.L., Maqueda, C. and Morillo, E., 1990. Cheese factory wastewater treatment by anaerobic semicontinuous digestion. Resour. Consem. Recycl.,3: 193-199. The processing of wastewater from a cheese factory in a semicontinuous anaerobic digester was studied. The experimental set-up consisted of six thermostatically-controlled digesters in a bath at 35 + 1'C, and magnetically stirred at 100 rpm. The best feeding for the culture medium was 0.633 g l-t day-t. The minimum hydraulic retention time was nine days. The efficiency of treatment varied between 90 and 780/0. The composition of biogas was of high quality, with 670/o of methane, and no trace of H2S.

Journal ArticleDOI
TL;DR: In this paper, pyrolignitic acid residues from wood pyrolysis were added to swine slurry in two laboratory anaerobic, fixed-bed, upflow digesters, filled with wood chips or PVC as support media.


Patent
07 Jun 1990
TL;DR: In this article, a process and an apparatus are described for the production of energy from biomass, the biomass if required ensiled or pelleted and fed to a biogas installation, in which natural fertiliser and natural gas from a public gas grid is burnt in a first apparatus and converted into thermal energy and/or electrical energy.
Abstract: A process and an apparatus are described for the production of energy from biomass, the biomass (at 10) if required ensiled or pelleted and fed to a biogas installation (12) in which biogas (arrow 20) and natural fertiliser (arrow 22) are produced. The biogas and/or natural gas from a public gas grid (26) is burnt in a first apparatus (30) and converted into thermal energy and/or electrical energy. By means of the electrical energy generated by the first apparatus (30) and, if necessary, by electrical energy from a public electricity grid (40) an electrolysis cell (34) is operated in which water is divided into hydrogen and oxygen. Hydrogen and oxygen can be converted back to electrical energy in a fuel cell (62), but the oxygen can also be used to improve the quality of wastewater (effluent) (at 60). The hydrogen can be stored in a storage facility (57) and/or be converted in a second apparatus (78) into thermal energy and/or into electrical energy or be used to drive motor vehicles (96) equipped with hydrogen engines.

Journal ArticleDOI
TL;DR: Eupatorium odoratum L. is a prolific producer of biomass among the weeds introduced into India and it can be used for energy production and it gave a higher count of cellulolytic and methanogenic bacteria than the untreated material.