Showing papers on "Biogas published in 1989"
TL;DR: In this article, a laboratory-scale anaerobic digester, fed with reconstituted skimmed milk as substrate, was intensively monitored to determine whether hydrogen could provide a useful new alarm/loading indicator for the Anaerobic digestion process with fast-fermenting substrates such as milk-sugars.
118 citations
TL;DR: In this article, the treatment of raw domestic sewage at ambient temperatures in an upflow anaerobic sludge blanket (UASB) reactor with a volume of 120 l and a height of 1.92 m was studied.
95 citations
TL;DR: In this paper, the authors examined the constraints on thermal pretreatment of sludge at temperatures in excess of 100 °C and its effects on subsequent anaerobic digestion, and concluded that thermal pre-treatment can positively affect the energy balance of the treatment plant.
89 citations
TL;DR: In this article, an up-flow anaerobic sludge blanket reactor process was used to treat cheese whey effectively, achieving over 97% chemical oxygen demand reduction with a constant hydraulic retention time of 5 days.
74 citations
TL;DR: A fixed-film bioreactor for H 2 S removal from biogas employing chemoautotrophic bacteria is reported here and it is found to be advantageous in many ways.
Abstract: A variety of «retained biomass» bioreactors have been developed, particularly for anaerobic digestion of industrial wastes. The fixed-film bioreactors are found to be advantageous in many ways. Reported here is a fixed-film bioreactor for H 2 S removal from biogas employing chemoautotrophic bacteria
55 citations
TL;DR: In this article, a 120-day fermentation period, in laboratory biogas digesters, of maize stalks, rice straw, cotton stalks and water hyacinth, each enriched with partially digested cattle dung, was monitored.
Abstract: Biogas generation and changes in total and volatile solids, total and NH4+ -N, available P, and numbers of cellulytic and acid-producing bacteria were monitored during a 120-day fermentation period, in laboratory biogas digesters, of maize stalks, rice straw, cotton stalks, and water hyacinth, each enriched with partially digested cattle dung. Maize stalks gave the greatest values of cumulative yield of biogas (65 L/2.5 L fermented material) and its methane component (39 L), whereas rice straw, water hyacinth, and cotton stalks produced progressively less biogas. Such a sequence was paralleled by the rate of loss of volatile solids. Peaks of biogas generation appeared within the 17th to 21st day of fermentation, according to the type of feedstock. Appreciable amounts of biogas were produced up to fifty days of fermentation. Maize stalks, rice straw, and water hyacinth followed, respectively. The level of available phosphorus released showed the order: water hyacinth > cotton stalks > maize stalks > rice straw. Peak numbers of cellulose decomposers appeared between the 10th and 20th day and those of the acid formers on the 20th day. Highest bacterial figures were shown by maize and cotton stalks for the cellulose decomposers, and by maize stalks and water hyacinth for the acid formers.
52 citations
TL;DR: A comprehensive study of the systems and equipment required to convert biogas into useful thermal and/or electrical energy was conducted, and the results published in the Handbook on Biogas Utilization (Walsh et al., Georgia Institute of Technology, Atlanta, GA, 1988).
50 citations
TL;DR: In this article, the operational characteristics, efficiency of treatment of landfill leachate, and recovery of energy in a laboratory scale hybrid bioreactor were investigated, which was a continuous upflow system combining a sludge bed and a filter and was operated at 35°C.
41 citations
TL;DR: In this article, the authors compared high and low-pressure biogas used in the compression ignition dual-fuel engine with respect to variation of power and the corresponding characteristic curve of the engine.
38 citations
TL;DR: In this article, two covers were placed on two anaerobic lagoons to study biogas production in poultry and swine lagoon, respectively, and the results showed that the poultry lagoon had a mean volumetric biOGas production rate of 0·07 and 0·05 m3/m3-day, respectively.
36 citations
Patent•
14 Sep 1989
TL;DR: In this article, a process for recycling and recovering solid urban waste and the like, consisting in subjecting solid urban wastes (SUW), after the removal (4) of any ferromagnetic material present therein, to high-pressure compression inside a screening press or a like, so as to separate the putrescible organic material (6) from the dry material (7) intended to form the combustible material; then subjecting the organic material to a process of anaerobic fermentation in a sealed and dry environment, allowing to extract, at the end of the fermentation cycle
Abstract: Process for recycling and recovering solid urban waste and the like, consisting in subjecting solid urban waste (SUW), after the removal (4) of any ferromagnetic material present therein, to high-pressure compression (5) inside a screening press or the like, so as to separate the putrescible organic material (6) from the dry material (7) intended to form the combustible material; then subjecting the organic material to a process of anaerobic fermentation in a sealed and dry environment, so as to allow to extract, at the end of the fermentation cycle, the biogas thus produced, which can be used directly for producing electric power or for other uses, the residuals of fermentation in the form of humus being subsequently subjected to refining and then to screening to recover the light materials; sifting, within a known rotary screen, the dry material so as to separate the combustible components, such as paper, fabrics, wood, plastics, leather and rubber, from the inert ones, such as glass, non-ferrous metals and any organic parts; the combustible components being then brought to a size suitable for a subsequent briquetting operation in order to obtain a stockable solid fuel.
TL;DR: In this article, the authors used rice straw, maize, and cotton stalks and poultry droppings, both as such and with either wheat straw litter or sawdust litter, for biogasification.
Abstract: Rice straw, maize, and cotton stalks and poultry droppings, both as such and with either wheat straw litter or sawdust litter, were used as substrates for biogasification. Water slurry combinations, each containing a crop residue and a type of poultry wastes, were prepared to achieve a uniform C/N ratio 30∶1 (w/w) and a total solids content 10% (w/v). Biogas generated and its methane component, as well as changes brought about in the major organic constituents of the feedstocks, were monitored in laboratory biogas digesters for 90 days at 35°C. The maximum cumulative volumes of biogas and methane, were respectively 30 and 14 l/l with rice straw plus wheat straw poultry droppings. The minimum volumes were 15 l biogas/l with cotton stalks + sawdust poultry droppings and 8 l methane/l with rice straw + sawdust poultry droppings. Rice straw combinations gave the highest rates of volatile solids disappearance, short-chain fatty acid formation, and NH4 -N liberation. No consistent trend among the poultry wastes mixed with each crop residue was evident. Changes in water-soluble substances, protein, fats, hemicellulose, cellulose and lignin depended on the components of each feedstock mixture.
TL;DR: The Neapolitan Yellow Tuff has been characterized by chemical, electron microscope and X-ray techniques and used for adsorption-desorption studies to separate carbon dioxide and hydrogen sulphide from methane in a simulated biogas mixture as mentioned in this paper.
TL;DR: A 25 L no-mix anaerobic digester was designed and fabricated in this article, which was designed to act as liquid-solid separator and had high nitrogen and ash concentrations.
Abstract: A 25 L no-mix anaerobic digester was designed and fabricated. The digester was designed to act as liquid-solid separator. The sludges obtained from the bottom of the digester had high nitrogen and ash concentrations while the effluent had no offensive odor. The performance of the no-mix digester was compared to that of a continuous stirred tank reactor at two temperatures and five hydraulic retention times. The no-mix digester had higher biogas production rate and pollution potential reduction.
TL;DR: In this paper, a unique anaerobic digestion system is outlined to treat sulfur rich wastes in which sulfide inhibition is minimized while maximizing energy recovery, using results from this investigation.
TL;DR: In this paper, a good start-up of digestion of tomato-processing waste (TPW) was achieved by the stepwise addition of feedstock over 10-12 weeks of digestion.
TL;DR: In this article, a 16 litre batch anaerobic reactor for treating piggery wastewater was used to evaluate the retention time of sludge in a cyclic anaerobatic SBR process.
TL;DR: The application of rumen microorganisms in an ‘artificial rumen’ reactor for the anaerobic fermentation of an organic fraction of domestic refuse was studied to optimize the acidogenic-phase digestion.
Patent•
10 Mar 1989
TL;DR: In this paper, a two-stage anaerobic treatment of liquid substrates with a high organic content in a reactor with two inter-connected chambers is proposed, in which the substrate is fed to the two chambers in accordance with the discharge principle at about one third of the height of the relevant liquid level or lower.
Abstract: A process for the two-stage anaerobic treatment of liquid substrates with a high organic content in a reactor (1) with two inter-connected chambers (3,4), in the first of which the hydrolysis and acid fermentation (fermentation chamber) takes place and in the second of which the methane digestion (digestion chamber) takes place, the substrate being introduced into the lower region of the digestion chamber (5) and the sludge arising from the decomposed organic materials being discharged separately from the waste water element of the treated substrate (6, 12) and the fermentation gas and the biogas which have been formed being drawn off above the liquid level (8, 13). In order to further develop a process of the generic type in such a way that the whole process of substrate treatment is accelerated and, furthermore, to create equipment for the carrying out of this process which is constructed as simply as possible and, with respect to the optimum capacities of the fermentation and digestion chambers, can be easily adapted to existing circumstances, that is to say, the degree to which the substrate to be treated is loaded with organic matter, it is proposed that the substrate is fed to the two chambers in accordance with the discharge principle at about one third of the height of the relevant liquid level or lower and that the substrate is withdrawn from the fermentation chamber from above (14).
TL;DR: This 6-year study investigated the suitability of effluent from an anaerobic biogas digester as a fertiliser for supporting crop growth and maintaining soil biochemical levels under rotational cropping.
Abstract: A 6-year study investigated the suitability of effluent from an anaerobic biogas digester as a fertiliser for supporting crop growth and maintaining soil biochemical levels under rotational cropping. The soil at the experimental area was predominantly a Fluvaquentic Eutrochrept. Comparisons were made with an inorganic fertiliser and a water-only treatment, using three crops (maize, oats, and kale) grown over a 2-year rotation. Dry matter yields were not consistently influenced by any of the treatments, apparently because of high soil-nutrient reserves. Thus the effectiveness of the effluent as a fertiliser could not be assessed. However, plant nitrogen concentrations were usually higher in the effluent and fertiliser treatments than in the water-only treatment for the last 3 years of the study. Soil organic C content for each treatment remained unchanged over the 6-year period. In contrast, microbial biomass, urease activity, and net mineral-N production (0–28 days) declined significantly in all ...
Patent•
02 Mar 1989
TL;DR: In this paper, a closed fermentation cell is used for the separation of the biogas from urban waste, with a non-woven textile covering the walls and the base of the cell and the flow of percolated suspension is recycled to the cell.
Abstract: The urban waste is crushed (2) to dimensions no greater than 5 cm and intimately mixed (5) with a aqueous suspension of biological sludge preconditioned at a temperature of from 40 to 100° C (6) and having a dry content of from 3 to 30% by weight, the suspension thus obtained, inoculated with bacterial strains (7) which can effect anaerobic break-down, being supplied to a closed fermentation cell (11, 12, 13) operated as a fluidised bed and being kept under anaerobic fermentation conditions in the cell until the emission of biogas has effectively ceased In the fermentation cell the suspension percolates through filtration means constituted by a non-woven textile covering the walls and the base of the cell and the flow of percolated suspension is recycled to the cell The filtration means also facilitate the separation of the biogas evolved
01 Jan 1989
TL;DR: In contrast to the extensive inventory of biomethanation processes which has been carried out within the EEC, until recently a detailed, up-to-date investigation of the end-sues of biogas had not been undertaken.
Abstract: In Europe over the past few years the generation of biogas for energy and environmental purposes has been gaining in importance. Industrial wastewaters, cattle manure, sewage sludges, urban wastes, crop residues, algae and aquatic biomass are all typical of the materials being utilized. In contrast to the extensive inventory of biomethanation processes which has been carried out within the EEC, until recently a detailed, up-to-date investigation of the end-sues of biogas had not been undertaken. To supply the necessary information, the Commission of the European Communities and the Belgian Science Policy Office jointly entrusted a study to the Unit of Bioengineering at the Catholic University of Louvain, Belgium. This book is record of the study and has the following key features: it gives a broad overview of the ongoing use of biogas in Europe; it summarizes available data on storage, purification and engines using biogas; it draws several conclusions concerning the technical and economic viability of the processes; it discusses the problems of using biogas; and it outlines recommendations and future R and D and demonstration projects in the field.
Patent•
19 Jan 1989
TL;DR: In this article, a process for anaerobic microbiological waste product utilisation which is suitable for converting to so-called biogas and high-grade natural fertilisers undiluted ammonia-containing aqueous dispersions and solutions containing biodegradable organic substances was proposed.
Abstract: The invention relates to a process for anaerobic microbiological waste product utilisation which is suitable for converting to so-called biogas and high-grade natural fertilisers undiluted ammonia-containing aqueous dispersions and solutions containing biodegradable organic substances like waste products of agriculture such as slurries, like waste products of the food industry such as slaughtering wastes and waste products of the chemical industry. The object is achieved by the fact that after the known substrate degradation together with carboxylic acids, a self-alkalisation of the digested sludge by the anaerobic fermentation can be surprisingly exploited in order to remove ammonia from a part of the reaction medium taken out of the circulation, alone or in a mixture with substrate. The mixture can be fermented without addition of diluents so that biogas and high-grade fertilisers are formed.
TL;DR: In this paper, the potential of Ricinus communis and Morus alba for methane production by anaerobic digestion was evaluated and it was shown that biological pretreatment of lignocellulosic substrates enhances biogas production besides producing a high percentage of methane.
TL;DR: The slurry produced 19·2 litres of biogas in nine weeks as compared to 16·5 litres produced by cow-dung alone, and the proteolytic, cellulolytic and methanogenic organisms were higher in E. tirucalli treatment.
TL;DR: In this paper, temperature profiles of continuously fed 3 m3 floating-drum type (KVIC) and fixed-dome type (Janta) biogas plants operating in the Indian hills were recorded during different seasons.
TL;DR: The solid waste originated during the biscuit and chocolate production was subjected to anaerobic digestion in a 180-litre capacity biogas plant of floating dome design and showed that the waste is amenable to an aerobic digestion.
TL;DR: In this article, a steady-state heat transfer analysis has been carried out for fixed-dome biogas plants (Chinese type), taking into account heat losses from the surface of the slurry inside the digester as well as the heat losses to the surrounding earth.