Evaluation of Lumber Recovery and Waste Generation in Selected Sawmills in Three Local Government Areas of Benue State, Nigeria
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© A publication of the School of Agriculture Technology, The Federal University of Technology, Akure, Nigeria. _______________________________________________________________________________________________________ Applied Tropical Agriculture Evaluation of Lumber Recovery and Waste Generation in Selected Sawmills in Three Local Government Areas of Benue State, Nigeria Ekhuemelo, D.O.* and Atondo, T. M. Department of Forest Production and Products, University of Agriculture Makurdi, Benue State, Nigeria. [email protected] ABSTRACT Volume of lumber recovered and wood wastes generated in some selected sawmills in three Local Government Areas (LGAs) of Benue State were assessed. Gwer East, Gwer West and Makurdi LGAs were purposively selected from Zone B and a total of ten (10) sawmills were randomly selected. Ten (10) logs were randomly sampled for conversion from each sawmills, making a total of 100 logs. The logs were converted using through and through sawing with band sawing machine. Input volume, volume of lumber recovered, percentage of lumber recovery, volume of sawdust, slabs, and bark were determined. The results revealed that Elmatandi sawmill in Naka, Gwer West LGA had the highest input volume, lumber recovery volume, and percentage lumber recovery of 1.7178 m3, 1.1698 m3, 0.6851 m3 and 68.51 m3 respectively. IDS sawmill in Makurdi had the lowest input volume, lumber recovery volume, sawdust volume and total volume of waste of 0.6034 m3, 0.3680 m3, 0.0063 m3 and 0.2355 m3 while Ire- Akari sawmill in Gwer West LGA generated the highest total volume of waste of 0.7561 m3. There was high positive significant relationship (p>0.01) between input volume and lumber volume (0.913**); input volume and sawdust volume (0.687**); as well as input volume and total waste (0.771**). IDS sawmill in Makurdi was the most efficient sawmill in terms of percentage lumber recovery and waste generation in study area. Keywords: Sawmill, lumber recovery, volume of waste, logs, volume INTRODUCTION wastes abound in Nigeria due to the activities of sawmill operators. The sawmill operators usually harvest round logs from the forest, transport them to their sawmills and saw the Nigeria is faced with the twin problems of solid wastes wood into lumbers of various dimensions. In the process, management, insufficient power generation and because of sawdust and other wood wastes such as wood bark, slab, log- the lack of better management approaches, wood wastes ends etc., are generated (Elijah, 2011). (especially sawdusts) were variously disposed along road sides, rivers, abandoned at the sawmills or openly combusted Sawmill industry in Nigeria is characterized by small scale (Elijah 2011). Ogunwusi, (2014) observed that generation of operators who mostly process timber with the CD series vast waste during wood processing operations substantially machine. Lumber recovery, which is defined as the reduce the quantity of wood resource availability for percentage of the volume of sawnwood output to that of the industrial use. It has been pointed out that less than 40% of volume of log input processed in the sawmill, regardless of round log from the forest are actually used at industrial level the type and kind of processing equipment adopted and the while the rest are disposed as waste. This makes the current species of wood involved (Badejo 1990), is low. Among the pattern of industrial wood utilization unsustainable and a reasons for the low lumber recovery rate are; small log source of threat to ability of the forests to sustain the wood diameter, length, taper and quality; kerf width of the sawing industry. machine; sawing variation, rough green-lumber size and size of dry dressed lumber; product mix; decision making by Sawmill account for 93.32% of the total number of wood sawmill personnel; condition and maintenance of sawmill based industries in Nigeria (Fuwape, 1998). According to equipment; and sawing method (Kukogho et al., 2011). The Ogunwusi (2014), the installed capacity and capital utilization objective of this study therefore was to assess wood waste of sawmills in Nigeria increased from 8,831,750 m3 in 1988 3 3 generation in selected sawmills in some Local Government to 15,793,188 m in 1992. It then decreased to 10,900,000 m Areas of Benue state, Nigeria. in 1996 and subsequently increased to 14,684,000 m3 in 2002 and 11,734,000 m3 in 2010. In 2010, the number of sawmills in Nigeria estimated at 1,325 (Ogunwusi and Jolaoso, 2012). MATERIALS AND METHODS With an average recovery rate of between 45-55% the waste generated in this subsector (e.g. bark, sawdust, trimming, split The Study Area wood, planer shavings and sander dust) was more than The study was carried out in Gwer East, Gwer West and 3 1,000,000m in year 2010 alone (Ogunwusi, 2014). Wood Makurdi LGAs of Benue State, Nigeria. These three LGAs 62 Ekhuemelo and Atondo Evaluation of Lumber Waste Generation in Selected Sawmills… Page 62 - 68 fall under Zone B geo-political Zone of the State. Zone B capital of Benue State. It is located within the Southern comprises of six (6) Local Governments namely; Gwer East, guinea savannah zone and between latitude 7.7306°N, and Gwer West, Makurdi, Guma, Tarka, Gboko and Buruku. longitude 8.5361°E with elevation of 97 m above sea level. Gwer west is located between Latitude 7.63oN and The total land area of Makurdi Local Government is 3,993.3 Longitude 8.22o E (NGND, 2015a). Gwer East LGA has its Km2 with a population of 297,393 people (Ityavyar, et al., headquarters were in the town of Aliade. It has an area of 2011; NPC, 2006). Gwer West LGA has its headquarters in 2,294 km² and a population of 163,647 at the 2006 census Naka. It has an area of 1,094 km2 and a population of 122,145 Wikipedia, 2015b; NPC, 2006). Gwer East is located between (NPC, 2006). Gwer West is located between latitude 7o 5oN Latitude 7.30oN and Longitude 8.48oE (NGND, 2015b). of the equator and longitude 9o 6oE of the equator. There are a Makurdi LGA is the traditional home of the Tivs and the total of 16 sawmills in the study area (Table 1). Table 1: Number of Sawmills in the Study Area S/No LGA Geographical Total No. of sawmills No. of Functional No. of Sampled zone sawmills sawmills 1. Gwer East B 5 5 4 2. Gwer West B 10 10 5 3. Makurdi B 1 1 1 Source: Field work, 2015. 8 00N 8 00N 8 01 E 8 10 E GUMA LGA NASARAWA STATE N River AGATU LGA Benue Hafilla MAKURDI TARKA GWER WEST Ogoluwa LGA APA LGA Apir Adekola Ire -akari El-matandi Igbor GWER EAST Segun GBOKO LGA Mase OTUKPO LGA Aliade River KONSHISHA LGA Saw Mill Kilometres LGA Boundary OBI LGA OJU State Boundary LGA 7 05 N 7 05 N 8 01 E 8 10 E Figure 2: Map of Makurdi, Gwer West and Gwer East LGA Showing the Location of Sampled Sawmills Source : Field work (2015) Figure 1: Map of Benue State showing all the Local Government Areas in the State (Source: http://nigeriazipcodes.com/385/benue-state-zip-code/) Sampling Design interview with five (5) operators in each sawmill was carried out to ascertain the efficiency of workers and machines used Ten (10) sawmills were purposively selected in the study area in each of the sawmills. based on functionality and accessibility. In each of the sawmills, ten (10) logs were randomly selected based on Table 2 shows the number of sampled sawmills in each of the dimension for assessment. Through and through techniques LGAs selected. Five (5) sawmills (50%) were selected from with band sawing machine was used to convert the logs into Gwer West, four (4) sawmills (80%) from Gwer East and one lumber; the numbers of the lumber pieces obtained were (1) sawmill (100%) from Makurdi. The number selected was recorded and residues were examined in order to determine based on the total number of sawmills available in each the percentage of lumber recovery. The procedure was LGAs. repeated for all the one hundred (100) sampled logs. Personal 63 Ekhuemelo and Atondo Evaluation of Lumber Waste Generation in Selected Sawmills… Page 62 - 68 Table 2: Sampled Sawmills in the Study Area S/N Sawmills Location Local Government Area 1. Ogoluwa Naka Gwer West 2. Adekola Naka ‘’ 3. Ire-Akari Naka ‘’ 4. Hafilla Naka ‘’ 5. Elmatandi Naka ‘’ 6. Segun Aliade Gwer East 7. Aliade Aliade ‘’ 8. Igbor Igbor ‘’ 9. Mase Mase ‘’ 10. IDS Makurdi Makurdi Source: Field work, 2015. Data Collection iv. Estimation of the volume of slabs The slab was sawn from the log to attain rectangular shape The method of Kukogho et al. (2011) was adopted in data and calculated using: collection. Before conversion, the length of each log, top girth, middle girth, basal girth and bark thickness of each log Volume of Slabs ( ) = … (Equation 4) was measured and recorded. The diameter (under bark and Volume of Slabs ( ) = … (Equation 5) over bark) at both ends was measured and recorded. The dimension of slabs and number of planks recovered were Total waste from slabs (m) = Volume of slabs ( ) x n recorded in prepared field notebook. ……………………… (Equation 6) Parameters of Determination Where: B = Base of the slab, T = Thickness of the slab, L = Length of the slab and n = no. of slab removed from a log. i. Determination of Log Volume: log volume was determined using Newton’s formula: v. Estimation of waste due to sawdust Log input Volume (v) L ( + 4Am+At) This was calculated as follows: ….……………..……….. (Equation 1) Where: π =3.142, L = Length of log, Ab = Cross sectional area at the basal Where: Wd = sawdust, V = Total volume of log (m3), Tr = Am = Cross sectional area at the middle and At = Cross volume of timber recovered (m3), Ws = slab (m3) sectional at the area top and Wb = bark volume (m3).