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Anaerobic Co-digestion of water hyacinth and cow dung for biogas production
После аналогичных подставок и преобразований для необходимого расхода бурового раствора получается:
Q =
Vm • mpr -Ар„) AP„
1,35F
4 • g •Ap- d 1,71 96,5 -p0’32 V’75
(12)
При недостаточном количестве бурового раствора плотность раствора, содержащего выбуренную породу, будет увеличиваться на величину, определяемую из зависимости
Ар
Vm • F4 (РТr ~Ро)
V, ■ F + Q
(13)
Соответственно увеличится забойное давление на величину ДР . Исходя из допустимого значения ДРизг, можно определить время, после которого необходимо осуществить дополнительную промывку ствола скважины, из соотношения
Т АР„ V - V,-у - Н (14)
Др.-Q
где, V - ось бурового раствора в скважине; Н - глубина скважины.
Заключение
1. Необходимый расход бурового раствора для своевременного удаления выбуренной породы из скважины следует определять из зависимостей (10) и (12).
2. Если нет технических возможностей для промывки при различных значениях производительности буровых насосов, дополнительную промывку следует осуществлять после начала механического бурения через отрезок времени, определяемый по зависимости (14).
Список литературы:
1. Ахундов Ф. А., Кулиев Р. Н., Сафаров Я. И. Установка для исследования транспортирующей способности потока бурового раствора частиц шлама в кольцевом пространстве. А. С. СССР № 1104397, МКИ Е 211347/00.
2. Сафаров Я. И., Ахундов Ф. А. Экспериментальные влияния некоторых добавок к буровым растворам на их транспортирующие способности. Сборник научных трудов, Баку, АзНИПИнефть, 1987. C. 16-22.
Oroka Frank Oke, Delta State University, Asaba Campus, Nigeria PhD in Crop Science, Department of Agronomy, E-mail: [email protected] Akhihiero Thelma, Delta State University, Oleh Campus, Nigeria PhD Chemical Engineering, Department of Chemical Engineering
E-mail: [email protected]
Anaerobic Co-digestion of water hyacinth and cow dung for biogas production
Abstract: Co-digestion of water hyacinth and cow dung under anaerobic condition was studied. Results indicate a progressive increase in biogas yield with increased cow dung in the co-ferment mixture ofwater hyacinth: cow dung Keywords: water hyacinth, cow dung, biogas, lag period
Introduction
With the ever increasing population of Nigeria and greater demand for energy sources for domestic and industrial use, much concerns has been raised about the sustainability of current and national energy sources, mostly based on rapidly depleting fossil fuel (i.e crude oil). The need for alternative energy sources have gained much attention, not only in Nigeria, but worldwide.
One ofthe identified naturally occurring biological energy storage resources is biomass, usually in complex organ-
ically bound substances formed through gross photosynthesis [1, 90-93]. Nigeria has abundant biomass resources which can be used to produce biofuels such as biogas. Identified feedstocks for an economically feasible biogas production include water hyacinth (Eicchornia crassipes Solms), water lettuce, animal dung, agricultural residues, sewage, etc. Anaerobic digestion processes are able to utilize a large number of organic materials as feedstock, including animal manure, human waste, crop residues, food processing and other wastes or a mixture of one or more of these.
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Section 6. Technical sciences
In Nigeria, identified feedstock substrate for an economically feasible biogas production includes water lettuce, water hyacinth, dung, cassava leaves and processing waste, urban refuse, solid (including industrial) waste, agricultural residues and sewage. It has been estimated that Nigeria produces about 227,500 tons offresh animal waste daily. In addition, 20 kg of municipal solid waste (MSW) per capita has been estimated to be generated in the country annually [2, 103; 3, 116-125]. Several authors have reported the potential of using water hyacinth in production of biogas for cooking instead of firewood [4,125-131; 5, 934-938]. Research results from the production ofbiogas from three animal manures and from water hyacinth-cow dung mixture were also reported by [6, 483-492]. They noted that biogas yield was highest with chicken manure (3.88 m 3/ton) while the cow dung-water hyacinth substrate was 0.64 m 3/ton. In Niamey, Niger in both hot (30-400C) and cool seasons (20-300C), [7, 73-78], biogas output during hot and cool seasons was also 0.52m 3 and
0.29m 3 respectively of biogas per m 3 of digester per day from water hyacinth and cow dung co-fermentation.
The study was therefore aimed at exploring the potential of biogas production from co-digestion of water hyacinth and cow dung under the discontinuous (batch) system.
Materials and Methods
The discontinuous digester (batch) system was used for this study. In this system the entire required amount of substrates to fill the digester was added once at the beginning of the digestion process and all are removed from the digester after completing the substrate digestion. This design was chosen for this study, because it is suitable, cheap and can be easily constructed by rural households and cooperatives with minimal cost.
A cone-closed floating dome discontinuous (batch) anaerobic digester was constructed made of reinforced concrete. The feed port dimensions were 50cm x 50cm, a concrete base of 1.5m and 1.5m wide reinforced concrete
walled digester that was 1.6 m deep. The gas collector 0.6m high and 1.0 m was constructed using 1.5 mm iron sheets and 20 mm central pipe.
Fresh water hyacinth (Eicchornia crassipes Solms) harvested from nearby river was chopped into 5 to 10cm pieces and dried. Cow dung was also dried. Four water hyacinth: cow dung proportions on dry weight basis aimed at investigating the efficiency of the mixture in biogas production. The four proportions of water hyacinth: cow dung on a weight percent basis were as follows: A= 75:25; B= 50:50; C= 25:75 and D=100:0.
The water content for each sample was determined using the recommendation for better biogas production as reported by [8, 48-57], that is total solid (TS) of 8% in the fermentation slurry. This was the basis for the determination of the amount of water that was added for any given mass of total solid. The proportion of total solid to water was same in all the fermentation slurry samples; 2.25m 3 of water to 180kg of solids. Preparation of fermentation slurry was by addition and vigorous mixing of total solid with an equivalent amount of water needed for maximum yield. Each sample mixture was introduced into the digester and observed over a 60 day period. This experiment was done in the rainy season (May -June) and repeated during the dry season (November -December).
Results and Discussion
Within a retention time of 60 days, 25:75 water hyacinth: cow dung mixtures consistently maintained a higher cumulative biogas volume, with a total cumulative biogas yield of 10.724 m 3 and 13.614 m 3 during the rainy season and dry season respectively. The 100:0 containing only water hyacinth recorded the lowest biogas yield of 7.279 m 3 and 9.398 m 3 during the rainy season and dry season respectively. Total cumulative biogas yield was higher in all the biogas digesters during the dry season compared to the rainy season.
Table 1. - Lag period, cumulative biogas yield and mean biogas yield per day at varying water hyacinth cow dung co-digested mixtures during the rainy season
Water hyacinth-cow dunj g mixture (% dry weight)
75:25 50:50 25:75 100:0
Lag period (days) 17 16 13 19
Cumulative biogas yield (m 3) 8.705 9.115 10.724 7.279
Mean volume of biogas yield per day (m 3) 0.145 0.152 0.179 0.121
SD 3.353 8.104 6.089 4.148
Increasing quantity of cow dung in water hya- tent with earlier reports by other researchers which cinth-cow dung co-digestion resulted in increased noted that combining animal dung with plant wastes cumulative biogas volume. These results are consis- catalyzes the biogas production with consequent in- 42
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Anaerobic Co-digestion of water hyacinth and cow dung for biogas production
creased yield [9,189-194; 10, 91-105; 11,535-539]. Co-digestion of water hyacinth with cow dung increased biogas yield by 47% (75% cow dung), 25% (50% cow dung) and 20% (25% cow dung) over water hyacinth alone. Co-digestion, which is the simultaneous digestion of more than one substrate in a single unit, has been shown to have better digestibility, enhanced biogas yield arising from availability of additional nutrients, as well as a more efficient utilization of equipment and cost sharing. Studies have shown that co-digestion of several substrates, for example, banana and plantain peels, spent grains and rice husk, pig waste and cassava peels, sewage and brewery sludge,
water hyacinth and sewage sludge have resulted in improved methane generation by over 40% compared to that of single substrates [12, 176-184; 13, 33-38; 14, 242-245; 15,131-140; 16, 72-77]. In addition, the use of cow dung as starter to provide microorganisms to serve as innoculum in the 100:0 treatments confirms earlier reports by [17, 534-560] on the inability of water hyacinth alone to stimulate the methanogen-esis process. They observed that water hyacinth has a high content of hemicellulose and cellulose, but the existing hemicellulose has a rather strong association with the lignin in the plant which makes it unavailable for the microorganisms.
Table 2. - Lag period, cumulative biogas yield and mean biogas yield per day at varying water hyacinth cow dung co-digested mixtures during the dry season
Water hyacinth-cow dunj g mixture (% dry weight)
75:25 50:50 25:75 100:0
Lag period (days) 15 15 11 17
Cumulative biogas yield (m 3) 9.398 12.764 13.614 7.412
Mean volume of biogas yield per day (m 3) 0.157 0.211 0.227 0.124
SD 4.264 7.251 7.232 3.028
Flammable gas production for the different mixture ratios also commenced at different lag periods (from the time of charging the digesters with the substrates to the time of gas flammability (Table 2 and 3). Biogas becomes flammable when the methane content is at least 45%. However, if it does not burn, it means the methane content is less than 45% and containing mainly CO2 [11, 535-539]. Longer lag phase of 19 (rainy season) days and 17 days (dry season) were observed for the water hyacinth alone, while the 25%:75% water hyacinth-cow dung co-digested mixture had shortest lag phase of 13 days (rainy season) and 11 days (dry season). Lag phase was reduced with pre-treatment of water hyacinth which further resulted in increased cumulative biogas
production of 15.892 and 16.120 m 3These results are not too different from the observation of other researchers. [7, 73-78] observed that biogas became flammable after 18 days in a 5m 3 biodigester using water hyacinth and cow dung, while [11, 535-539] reported lag phase of 5 to 9 days in a 121 litres biodigester under varying water hyacinth based treatments. Mean volume of biogas yield increased in the following order of percentage water hyacinth-cow dung mixture; 100:0 (0.12 m 3)> 75:25 (0.145 m 3) >50:50 (0.152 m 3)> 25:75 (0.179 m 3). Variation in daily gas production over the 60 day retention time was higher in 25: 75 water hyacinth-cow dung mixtures and least in the 50: 50 water hyacinth-cow dung mixture.
References:
1. Zuru, A. A., Abubakar, A. and Ekpekurede, A. A study of the effect of addition of calcium, boron, cobalt ions and the combination of three ions on biogas production from cow dung Nigeria Journal of Renewable Energy volume 3 (1, 2), 1997.
2. Matthew P. Gas production from animal wastes and its prospects in Nigeria. Nigerian J. Solar Energy. Volume 2, 1982.
3. Mshandete A.M and Parawira W. Biogas technology research in selected sub-Saharan African countries - A review. Afr. J. Biotechnol. Volume 8, 116-125.
4. Kivaisi, A. K. and Mtila, M. Production of biogas from water hyacinth (Eichhornia crassipes) (Mart) (Solms) in a two-stage bioreactor, World J. Microb. Biot., volume 14, 1998.
5. Kumar, S. Studies on efficiencies of bio-gas production in anaerobic digesters using water hyacinth and night-soil alone as well as in combination, Asian J. Chem. Volume 17, 2005.
6. Ntengwe, F.W; Njovu, L.; Kasali, G., Witika, L. K. Biogas production in cone-closed floating dome batch digester under tropical conditions International Journal of ChemTech Research volume 2, 2010. 43
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7. Almoustapha, O.; Kenfack, S. and Millogo-Rasolodimby Biogas production using water hyacinth to meet collective energy needs in a Sahelian country Facts Report Action Science, 2009.
8. Ituen E. E., John N. M. and Bassey B. E. Biogas production from organic waste in Akwa Ibom State of Nigeria. Appropriate Technologies for Environmental Protection in the Developing World. Selected Papers from ERTEP 2007, July 17-19, Ghana, 2007.
9. Radhika L.G, Seshadri S. K, Mohandas P. N. Biogas production from a mixture of Coir pith and cattle waste. J. Chem. Technol. Biotechnol. Volume 33, 1983.
10. Uzodinma, E. O. and Ofoefule, A. U. Biogas production from blends of field grass (Panicum maximum) with some animal wastes International Journal of Physical Sciences 4, 2009.
11. Ofoefule, A.U, E. O. Uzodinma and O. D. Onukwuli, O. D. Comparative study of the effect of different pretreatment methods on biogas yield from water Hyacinth (Eichhornia crassipes) International Journal of Physical Sciences volume 4, 2009.
12. Ezekoye V. A. and Okeke C.E Design, construction and performance evaluation of plastic bio-digester and the storage of biogas, The Pacific J. Sci. Technol. volume 7, 2006.
13. Ilori M. O., Adebusoye A., Lawal A. K. and Awotiwon O. A. Production ofbiogas from banana and plantain peels, Adv. Environ. Biol., volume 1, 2007.
14. Adeyanju A. A. Effect of seeding of wood-ash on biogas production using pig waste and cassava peels, J. Eng. Appl. Sci., volume 3, 2008.
15. Babel S., Sae-Tang J. and Pecharaply A. Anaerobic co-digestion ofsewage and brewery sludge for biogas production and land application, Int.J. Environ. Sci. Tech., 6, 2009. 131-140.
16. Patjj, J.H, Molayan, L. A.R, Bhargav, S. and Sawmya S. A. Anaerobic co-digestion of water hyacinth in primary sludge Research Journal of Chemical Sciences volume 1, 2011.
17. Eltawil M. A.1, E. B. A. Belal Evaluation and scrubbing of biogas generation from agricultural wastes and water hyacinth Mis. J. Agric. Eng. Volume 26, 2009.
Romanov Konstantin Alexandrovich, Scientific Investigation Institute of Federal Service of Penal System Russian Federation, Moscow, research associate E-mail: [email protected] Djuzheva Elena Viktorovna, Scientific Investigation Institute of Federal Service of Penal System Russian Federation, Moscow, research associate E-mail: [email protected] Ponomarev Sergey Borisovich, Scientific Investigation Institute of Federal Service of Penal System Russian Federation, Izhevsk, Doctor of Medicine, professor,
Director of the branch E-mail: [email protected] Baranova Darya Vladimirovna, Kalashnikov Izhevsk State Technical University, Izhevsk, master student E-mail: [email protected]
System aspect of informatization monitoring of cardiac care in Russia’s penal system
Abstract: The article describes the informatization process of monitoring cardiac care in the penal system of Russia from the standpoint of system analysis. The study describes a new software package that allows real-time to
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