CC BY
22
COMPOSTING USING WOOD WASTE PRODUCTION Gurbanova R.V.1, Javadova G.Sh.2 Em ail: [email protected]
'Gurbanova Rena Vagif - Candidate of Chemical Sciences, Associate Professor;
2Cavadova Gunay Shakir — Master Student, SPECIALTY: SOLID WASTE PROCESSING TECHNOLOGY, DEPARTMENT OF CHEMISTRY AND INORGANIC SUBSTANCES, CHEMICAL TECHNOLOGY FACULTY, AZERBAIJAN STATE UNIVERSITY OF OIL AND INDUSTRY, BAKU, REPUBLIC OF AZERBAIJAN
Abstract: composting is the less expensive and effective method of wood waste utilization. The product obtained can be used to increase soil fertility, optimization of the composition of the humus contained in it, mineral substances and improvement of its structure. With this purpose composting using wood dust and cow dung has been carried out within 35 days. N, P and K content, temperature and pH of the compost are monitored.The results of analyses of composts samples taken every five days showed increase of N,P and K from 4.53%, 3.25%, 2.8% to 9.7%, 7.63%, 8.9%.The temperature of the compost increased higher 50 0 C after 30 days of composting. pH of the compost obtained was 9.0.During composting wood waste is a good soil conditioners when mixing with cow dung. Keywords: sawdust, composting of waste, timber, cow dung.
КОМПОСТИРОВАНИЕ С ИСПОЛЬЗОВАНИЕМ ДРЕВЕСНЫХ
ОТХОДОВ Гурбанова Р.В.1, Джавадова Г.Ш.2
'ГурбановаРепа Вагиф - кандидат химических наук, доцент;
2Джавадова Гюнай Шакир — магистрант, специальность: технология переработки твердых отходов, кафедра химии и неорганических веществ, химико-технологический факультет, Азербайджанский государственный университет нефти и промышленности, г. Баку, Азербайджанская Республика
Аннотация: компостирование относится к наименее затратным и эффективным способам утилизации древесных отходов. Получаемая при этом продукция может потребоваться для повышения плодородия почвы, оптимизации состава содержащихся в ней гумуса и минеральных веществ и улучшения ее структуры. С этой целью было проведено компостирование с использованием опилок и коровьего навоза в течение 35 дней. Содержание N, P и K, температура и pH компоста отслеживается. Результаты анализов проб из компоста, взятых через каждые пять дней, показали увеличение содержания N, P и K с 4.53%, 3.25%, 2.8% до 9.7%, 7.63%, 8.9%. Температура компоста повысилась выше 50 оC через 30 дней компостирования, pH полученного компоста составляет 9.0. Во время компостирования опилки являются хорошими кондиционерами почвы при смешивании с коровьим навозом. Ключевые слова: опилки, компостирование отходов, древесина, коровий навоз.
UDC 628.477
In the process of timber and wood processing, wood waste of various types and qualities are inevitably generated. The annual volume reaches several hundred million tons. Wood waste is partially processed with the production of fiberboard, wood chipboards [1, 2]. Also, a significant proportion of wood residues are used for heating industrial and residential premises. But the rest of the waste remains unprocessed and pollutes the felling sites and the territory of timber processing enterprises. It is also worth considering that these are official figures, while the real volume of rotting wood waste is much higher [6].
In our opinion, the most rational way of processing of unused wood residues is their composting.
Wood waste composting is not only a fairly cheap way of processing it, but also promising from an environmental point of view.
The bark of coniferous and deciduous trees is more effective for composting, and even better is woody greens after hydrothermal treatment. Their utilization in this direction is also favored by the higher content of mineral substances in them in comparison with wood (3-5%), which are necessary for the development of agricultural plants. Bark and woody greens are effective sources of soil
supplementation with micro and macro elements. In addition, waste is able to filter and adsorb components that are harmful to crops brought by soil water and gradually release the elements that are useful for plants, primarily potassium and magnesium.
It is important that the introduction of bark, sawdust, and other wood waste improves the structure of the soil, making it lumpy. On such soils, as a rule, acidification is not observed, moisture capacity and friability increase. All this provides an increase in yield.
The increase in productivity is also due, to the activation of microbiological processes, especially those associated with the conversion of carbon. At the same time, accelerated destruction increases the need for microorganisms in nitrogen and creates its deficiency.
It should be also paid attention to one of the aspects of the use of wood waste in the cultivation of agricultural products both in open ground and in greenhouses. Its essence lies in the heat supply of the root environment. Heat is formed due to the course of biological exothermic reactions of the components of plant tissues. The validity of this concept has been proven experimentally.
The resulting composts are usually used as a means of improving soil fertility compositions. Their quality usually depends on the composition and type of raw materials selected for composting, as well as on the ratio of organic carbon to nitrogen in them. Currently, in our country and abroad, there are large industrial enterprises with a capacity of over 1000 tons/year for the processing of organic waste into composts. Composting wood waste is not only a fairly cheap way of processing it, but also promising from an environmental point of view.
As a rule, the main disadvantage of many modern composting methods is significant energy consumption and the duration of the process, which in some cases reaches several years.
To speed up the composting process, various methods have been proposed for adding popstyrene to the compostable mixture to improve mass transfer and porosity of the compost [3], crushing organic waste and composting at a temperature of 55-65% C [4], as well as composting in the presence of ozone [5]. However, all these methods, although they speed up the composting process up to 3-4 months, at the same time significantly increase its cost due to the creation of complex technological systems for carrying out the process.
The purpose of the work is to improve the quality of the compost obtained using sawdust and cow dung. Raw sawdust was mixed with cow dung to adjust the starting carbon to a starting carbon ratio to a 20 to 30 ratio, and the moisture content was adjusted to 60-70%.
The composter was made of polyethylene and has a capacity of 45 liters. Forced aeration was achieved by composting once a day. The pH and temperature of the compost was also controlled. The composter contains approximately 20 kg of substrate. The compost heap was kept for 35 days. A sample from the composter was taken every 5 days for laboratory analysis.
At a temperature of 106.0 ° C, the moisture content was determined by drying to constant weight. The pH was measured with a pH meter.
The temperature was determined with a thermometer at a compost depth of 55 cm.
Discussion results
The ratio of carbon to nitrogen is one of the main factors that influence the growth of microorganisms leading to the decomposition of organic waste and release of nitrogen during composting. So as microorganisms utilize about 30 parts of carbon per 1 part of nitrogen, then theoretical-optimal C / N ratio should be 30: 1 for any compostable mass. In this study, the C / N ratio of substrates was 25: 1. The sawdust has a C / N ratio of 102.0 as shown in Table 1, which shows that the organisms that manage compost cannot survive in the sawdust due to a lack of nitrogen.
Table 1. Characteristics of raw materials
Material Total carbon,% Nitrogen,% PH Moisture content,% C/N
Sawdust 36,5 0,4 6,4 47 102,0
Cow dung 60,7 5,73 6,8 58 14,0
The C / N ratio of a nitrogen rich substrate is significantly lower than shown in Table 2 and therefore will produce an unpleasant odor during composting due to the mineralization of excess nitrogen to ammonia.
Moisture Total N, % ^ % R, % рн ON
content,% carbon,%
Sawdust plus cow dung
13,0 70,95 3,58 5,9 1 5,2 1 6,8 22
N, R, K - are important nutrients required for plants in large quantities. Nitrogen is necessary for the growth of microbes, as it is part of the protein, which makes up more than 52% of the dry brush mass of the bacteria [7]. The correct combination of nitrogen rich organic waste with sawdust increases the decomposition of the sawdust and release of nutrients during composting. According to [8], sawdust retains nitrogen because it decomposes, but it is a good source of energy for microorganisms due to its high carbon content. A mixture of sawdust and cow dung showed high nitrogen mineralization as shown in Figure 1.
Fig. 1. Change in the percentage composition of N, P andK for sawdust and codung
Composting occurs mainly in two temperature ranges, known as mesophilic (10-40 ° C) and thermophilic (above 40 ° C).
Compost temperature is a good indicator for microbial development. At temperatures above 60 ° C, the activity of many organisms decreases. Therefore, the optimal temperature range is from 32 ° C to 60 ° C. There is a direct relationship between temperature and the rate of oxygen consumption.Figure 2 shows the change in temperature over time during composting. An increase in temperature is observed with a change in time from 10 to 30 days.
Fig. 2. Temperature change of substrates bytime when composting
Initially (from 10 to 13 days), the pH decreases due to decomposition of organic matter, leading to the formation of organic and inorganic acids. On the 15th day, an increase in pH caused by the
decomposition of organic substances containing nitrogen occurs. This leads to the formation of NH3, which react with H2O to form ammonium hydroxide.
So, the results of analyzes of samples from composters taken every five days showed an increase in the content of N, P, K in compost from 45.3%, 3.25%, 2.80% to 9.7%, 7.63%, 8.9%.
References / Список литературы
1. Kanmani P., Karuppasamy P. Investigations of lingo-cellulosic biodegradation of corn waste in solid phase fermentation using Phanerochatechrysosporium and Rhizopusstolonifer, Afr. J. Biotechnol. 8, 24, 2009. 6880-6887.
2. Oshima T, Moriya T. // Ann. Acad. Sci, 2008. T. 1125. № 1. P. 338-344.
3. WangX., Cui H., Shi J., ZhaoX., Zhao Yu, Wei. // Biores. Technol., 2015. Vol. 198. Pp. 395-402.
4. De Gannes V., Yudoxi G., Hickey W.J. // Borders inMicrobiology, 2013. T. 6. Art. 164. Pp. 1-9.
5. Sanchez O.Dzh., Ospina D.A., Montoya S. // Waste management, 2017. Vol. 69. Pp. 136-153.
6. Pakhnenko E.P. Sewage sludge and other untreateddietary organic fertilizers. 3rd ed. M.:BINOMIAL. Knowledge Laboratory, 2015. 314 p.
7. Mironov V.V., Ivanov Yu.A. // Agricultural mechanizationin Asia, Africa and Latin America, 2018. Vol. 49. № 3. S. 86-90.
8. Smith J.L., Collins H.P. Soil microbiology, ecology andBiochemistry. 3rd ed. Academic Press, 2007. Pp. 483-486.
