Theoretical analysis of the heat energy savings in wood pellets production

  1. R. Georgiev, K. Peychev, V. Dimova, Georgiev


Department of Agricultural Engineering, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria


DOI: 10.15547/ast.2018.03.048

(Manuscript received 4 June 2018; accepted for publication 6 August 2018)


Abstract. The report includes a theoretical analysis of the heat energy savings in the drying of wood biomass with desiccant fumes. With the current technological schemes for drying wood pellets most heat is lost with the exhaust fumes.To use the heat of exhaust fumes it is propose to utilize these by a heat exchanger recuperator type, which transfers part of the heat of the exhaust gas to the fresh air entering the dryer installation. Thus, about 25% of the heat for drying biomass can be saved. The report examines the relationship between outdoor temperature and condensation of moisture from the exhaust gases on the relative share of energy saved using a heat exchanger.

Differences in carbon forms under two land use types in Abia State, South-east Nigeria

B.N. Ndukwu1, D.N. Osujieke2, C.M. Ahukaemere1, P.E. Imadojemu2


1Department of Soil Science and Technology, Federal University of Technology, PMB 1526 Owerri, Imo State, Nigeria

2Department of Soil Science and Land Resources Management, Federal University Wukari, PMB 1020 Wukari, Taraba State, Nigeria


DOI: 10.15547/ast.2018.03.047

(Manuscript received 21 May 2018; accepted for publication 29 July 2018)


Abstract. The storage of carbon in the soil helps to sustain the ecosystem of our environment. However, this study was to determine the differences in carbon forms (total carbon, organic carbon and inorganic carbon) under selected forest and pasture land use types in Abia State, Nigeria. Two profile pits were sung on each of the land use types using free survey technique. The profile pits were sampled based on horizon differentiation for routine and special laboratory analyses. The data obtained were statistically analyzed for coefficient of variation and correlation. Total carbon had mean of 2.07% and 2.12% for profiles 1 and 2 under pasture land use and 2.46% and 2.45% for profiles 3 and 4 under forested land use. Organic carbon as indicated by the mean was higher in forest land (profile 3=1.85%, profile 4=2.09%) than in pasture land (profile 1=1.37%, profile 2=1.40%) while inorganic carbon was higher in pasture land (profile 1=0.70%, profile 2=0.72%) over forest land (profile 3= 0.39 %, profile 4= 0.36 %). Organic carbon had high variation (≥45.97% ≤ 49.38%) in profiles of the pastured land use while it had low – moderate variation (≥12.55% ≤ 27.03%) in profiles of forested land use. Also, inorganic carbon recorded moderate variation (≥16.12% ≤ 25.95%) in profiles of pasture and forest land use types. The forest land use type was determined to contain more forms of carbon when compared with the pasture land use type.

Heavy metals in organs of gudgeon (Gobio gobio L.) from Vardar River, R. Macedonia

R. Nastova*, V. Kostov, I. Ushlinovska

Institute of Animal Science, “Ss. Cyril and Methodius” University, Blvd. Ilinden 92 A, 1000 Skopje, Republic of Macedonia (Manuscript received 4 August 2017; accepted for publication 13 November 2017)

Abstract. Ecotoxicological examinations based on seven heavy metals (Fe, Cu, Zn, Mn, Cd, Pb and Cr) concentrations in organs of gudgeon (Gobio gobio L.) caught by 14 monitoring points at Vardar River in Republic of Macedonia were performed. The organ’s samples elements were read-out on AAS in flame and graphite cuvette. Significant increase of Pb and Cd contents in liver, gills and gonads of fish sampled downstream Skopje and the town of Veles was found. It should be pointed out that at times Cd concentrations in muscles were as high as 0.518 mg/kg which is significantly over the maximally allowed concentrations for human nutrition.

Biodiversity of the macrozoobenthos in some protected marine areas along Bulgarian Black Sea coast

E. Petrova*, S. Stoykov

Institute of Fish Resources, 9000 Varna, Bulgaria
(Manuscript received 30 August 2017; accepted for publication 6 November 2017)

Abstract. The aim of this paper is to establish the biodiversity status of the macrozoobenthos in some protected marine areas (NATURA 2000) along the Bulgarian Black Sea coast. The observation stations in the period 2010-2012 were within the frames of the following habitats: 1160 – Large shallow inlets and bays; 1110 – Sandbanks, slightly covered by seawater and Sublittoral mussel banks on sediment. In general, the data shows steady state compared to the 1980s, except for the area near Kamchia River, characterized by low biodiversity due to water pollution from the river inflow (with contaminants from agricultural and industrial sources in the upper river stream) and less salinity leading to marine mussel species reduction. In the border area, near the Emona zone, the black mussel catches varied between 160-600 kg in 2005, while only single specimens were detected in 2013. In the same field, the yield of Rapana venosa was within the limits of 5-40 kg in 2005 and between 80-160 kg in 2013. The established variability showed a dynamic balance between Mytilus galloprovicialis and Rapana venosa that pose a challenge for future stock of the black mussel and point the need of regular monitoring.

Taxonomic composition of phytoplankton in Black Sea area in front of the Cape Galata (2008-2016)

D. Klisarova, D. Gerdzhikov

Institute of Fish Resources, 9000 Varna, Bulgaria
(Manuscript received 13 August 2017; accepted for publication 3 October 2017)

Abstract. In this article have been investigated the taxonomic structure of the phytoplankton communities developing in the Black Sea area in front of the Cape Galata. For the period 2008 – 2016, relatively high species diversity was found (161 species). Throughout the most of the year dominated class Dinophyceae (up to 54.17%). The number of phytoplankton species decreased with distance from the shore, but the percentage participation of the group of peridineas and diatoms in the general taxonomic composition grew. Only in class Prymnesiophyceae increased biodiversity was registered in the high seas

Inventory of the legal base for reclamation of lands disturbed by open-cast mining in Bulgaria

M. Banov*, V. Tzolova, I. Kirilov

N. Poushkarov Institute of Soil Science, Agrotechnologies and Plant Protection, 1080 Sofia, Bulgaria (Manuscript received 4 July 2017; accepted for publication 18 October 2017)

Abstract. Samples of geological materials, used for reclamation of land, disturbed by open coal mining have been investigated. The obtained results for the opportunities of biological regeneration of the lands fertility, reclaimed with these materials, put them in the following order: Pliocene clays from the region of Maritza Iztok (the biggest energy complex with the largest open coal mine in Bulgaria); marl materials from the area of the town of Pernik; and last – sulfur containing materials from the region of Chukurovo Mine, Sofia region. It is proposed that the period for biological reclamation, shown in Article 4, item 2 §(а) from Regulation No. 26/1996 for reclamation of disturbed areas, improvement of lands of low productivity, removal and utilization of the humus layer, must be changed from”5years”to”7-12years”for the lands reclaimed without humus and to”3-5years”for the lands reclaimed with of humus horizon used.

Saved СО2 emissions by using renewable sources for hot water yield in Bulgarian dairy farms

R. Georgiev1*, R. Slavov2, K. Peychev1, D. Georgiev1, S. Apostolov3, J. Ellingsen4, J. Tønnesen4

1Department of Agricultural Engineering, Faculty of Agriculture,Trakia University, 6000 Stara Zagora, Bulgaria
2Department of Animal Science – Ruminant Animals and Dairy Science, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria 3Bioselena Foundation for Organic Agriculture, Bulgaria
4Royal Norwegian Society for Development, Norges Vel, Norway

(Manuscript received 13 September 2017; accepted for publication 10 November 2017)

Abstract. In 2014 – 2015 installations for hot water yield from renewable energy sources were built and tested in three dairy farms in Bulgaria. These replace the traditionally used electricity on farms with the aim of decarbonising the energy production. The newly built installations contain three modules for heat yield – from recuperation of the heat from the milked milk, from the solar energy and from wood pellets. In the course of one year the energy obtained from the renewable sources has been measured and assessed. The present article assesses the ecological benefits of the separate renewable sources which are used to reduce СО2 emissions, the main greenhouse gas. For this purpose, the method of environmental life cycle analysis (LCA) and assessment of heat/hot water generating systems was used. Coefficients for calculating the primary energy of the saved or replaced energy, as well as their respective carbon ratios, specific for Bulgaria, were used. The results obtained are related to identifying the specific quantities of saved CO2 emissions from the renewable sources used on the experimental farms. It has been found that about 52-57% of CO2 savings are due to the pellets used, 34-42% to the solar heat collectors and about 9% to the recuperated heat from the produced milk.

Ecological analysis of the flora in the ‘Chinarite’ protected area – Rodopi municipality, Bulgaria

L. Dospatliev1*, M. Lacheva2

1Department of Pharmacology, Animal Physiology and Physiological Chemistry, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria;
2Department of Botany, Faculty of Agronomy, Agricultural University, 4000 Plovdiv, Bulgaria

(Manuscript received 10 June 2016; accepted for publication 21 August 2017)

Abstract. The aim of the present study was to make an ecological analysis of the floristic composition in the protected area ‘Chinarite’ Rodopi municipality, Bulgaria in terms of its biological spectrum, biological types and phytogeographic elements and an assessment of the anthropogenic effect on it. In studied protected area were identified 147 species of vascular plants, of them 8 species included in the Red List of Threatened Species of the International Union for Conservation of Nature (IUCN). 73 medicinal species, 55 nectariferous plants and 10 tertiary relicts were recorded. The anthropogenic impact on the protected area is obvious and it has affected to the greatest degree the species composition of vascular plants, which encompasses a large number of weeds – 28 species,ruderals-29species,alien -5speciesandinvasive-6species.

Avifauna abundance and diversity in Jos wildlife park, Nigeria

B.T. Kwaga1, D. Iliya1, A. Ali1, D. Khobe2*

1Department of Forestry and Wildlife Management, Federal University of Technology, Yola, Nigeria 2Department of Animal Production, Adamawa State University, Mubi, Nigeria

(Manuscript received 1 June 2017; accepted for publication 30 August 2017)

Abstract. There is a great need to determine the abundance and diversity of any ecosystems biodiversity through its species composition and richness. This study compared the diversity and abundance of bird (avifauna) species in three habitats of the Wildlife Park, Plateau State, Nigeria. The three vegetation types (Gallery, Savannah and the Rocky areas) were surveyed. Fifteen (15) line transects (five in each of the habitats) were laid in the morning and evening hours. The data obtained were subjected to descriptive statistics (mean and percentages). Simpson’s diversity index was also employed in assessing the diversity of avifauna species in the study area. The result obtained indicated that a total of 616, 569 and 363 birds were recorded in the morning hours while a total of 117, 140 and 115 were identified in the evening. The results of birds species diversity (morning and evening) indicated that transects II (0.5956) and I (0.7407) for Gallery forests, transects II (0.6946) and III (1.000) for Savannah V (0.0784) and I (0.0752) for Rocky habitats, respectively, had the highest birds diversity. It is recommended that pastoralists and Plateau State Government should liaise and provide alternative grazing reserves to minimize the encroachment of the pastoralists into the Park and other protected areas.

Influence of basic agrotechnical activities on the productivity and yield of Triticum monococcum L.

S. Stamatov*, K. Uzundzhalieva, E. Valchinova, G. Desheva, P. Chavdarov, B. Kyosev, T. Cholakov, R. Ruseva, N. Velcheva

Institute of Plant genetic Resources „Konstantin Malkov”, 2 Druzhba, 4122 Sadovo, Bulgaria (Manuscript received 7 June 2017; accepted for publication 25 August 2017)

Abstract. The study was conducted during the period 2014 – 2016 in the experimental field of Institute of Plant Genetic Resources, Sadovo. The influence of the period of sowing, the predecessor and the fertilization on the elements of productivity and grain yield per hectare in einkorn wheat were studied. It was established that the structural elements of productivity – number of productive tillers, length of the spike, number of spikelets per spike, mass of central spike, number of grains in central spike, weight of the grains from the central spike are with the highest values in plants grown after predecessor peas, sown in autumn and fertilized with extra nitrogen. With least developed productive capabilities are the plant variants sown in spring after sunflower and without additional fertilization with nitrogen. With proved the biggest impact on grain yield per hectare is the date of sowing. The sources of variation: predecessor and combined effect of factors predecessor x fertilization show equal share of influence on the productivity of einkorn. The results from the study give science-based information on the most favorable time of sowing, fertilizing and predecessor in einkorn.