http://dr.lib.sjp.ac.lk/handle/123456789/10712 Wed, 07 Jan 2026 06:16:29 GMT 2026-01-07T06:16:29Z http://dr.lib.sjp.ac.lk/handle/123456789/10742 Treatment of Landfill Leachate using Sequencing Batch Reactor Perera, W.D.M.C.; Bandara, N.J.G.J.; Jayaweera, M. In Sri Lanka municipal solid waste is generally disposed in poorly managed open dumps due to lack of liner systems and leachate collection systems. Rain water percolates through the waste layers to produce leachate which drains into ground water and finally to nearby water bodies, which cause degrading the quality of water. Leachate thus has become a major environmental concern in municipal waste management and treatment of leachate is a major challenge for the existing and proposed landfill sites. The present study was conducted to assess the feasibility of the usage of the Sequencing Batch Reactor (SBR) in the treatment of the landfill leachate up to the proposed levels in the draft report of “Proposed Sri Lankan standards for landfill leachate to be disposed to the inland waters". Leachate collected from the open dumpsite at Meethotamulla, Western Province, Sri Lanka was used for leachate characterisation. The SBR was constructed with a 10 L working volume operated in an 18 hour cycle mode and each cycle consists of 15 hrs of aerobic, 2 hrs settle and 0.5 hrs of fill/decant stages. The Dissolved Oxygen (DO) level within the SBR was maintained at 2 mg/l through the aerobic stage. Infeed was diluted with water during the acclimatisation period and a leachate to water ratio of 55:45 was maintained. The removal efficiencies for different parameters were; COD=90.5%, BOD=92.6%, TS=92.1%, conductivity=3.9%, alkalinity=97.4%, hardness=82.2%, Mg=0.5%, Fe=94.2%, Zn=63.4%, Cr=31.69%, Pb=99.6%, sulphate=98.9%, and P=71.4%. In addition, Ni and Cd were completely removed during a single SBR cycle. The dilution of leachate in the dumpsites using municipal wastewater, groundwater or rainwater was identified as the most cost effective dilution methods. The effluent from the SBR proposed to be further treated using a constructed wetland before releasing to surface water. Wed, 01 Jan 2014 00:00:00 GMT http://dr.lib.sjp.ac.lk/handle/123456789/10742 2014-01-01T00:00:00Z http://dr.lib.sjp.ac.lk/handle/123456789/10738 Stock Density and Fruit Yield of African Walnut in Tropical Lowland Rainforests of Southwest Nigeria Amusa, T.O.; Jimoh, S.O.; Azeez, I.O. Despite the high socio-economic potentials of African walnut, Plukenetia conophora Mull-Arg, there is a dearth of information on stock density and yield studies under different site conditions. Therefore, this study was carried out to investigate the stock density and fruit yields of P. conophora in three different habitats (i.e. less disturbed natural forest, recently disturbed natural forest and plantation forest) within Omo Forest Reserve (OFR) and Shasha Forest Reserve (SFR) of Nigeria. Stratified random sampling was used to carry out the inventory survey. Fruit yields were determined by collecting fruit falls through double sampling approach. Both descriptive and inferential statistics were used in analysing the data at p=0.05. Stock densities of P. conophora were 5.33+1.7 stands/ha, 14.67+2.05 stands/ha and 16.00+2.94 stands/ha in OFR, while they were 7.33+0.47 stands/ha, 14.67+1.25 stands/ha and 10.67+04.7 stands/ha in SFR for recently disturbed forest, less disturbed forest and plantation forest respectively. There were significant differences in number and distribution of species by forest types, but not between forest reserves. The mean yield of P. conophora was estimated at 7,800 kg/ha/yr for OFR and 6,534 kg/ha/yr for SFR. Yields from plantation area contributed more in OFR, while yields from less disturbed natural forest area were higher in SFR. Yields from recently disturbed natural forest were consistently lower in the two reserves. These results show that P. conophora thrives better in plantation and old re-growth forests. This information is pertinent towards improving the management of the species, increase its productivity and enhance benefits in a more sustainable manner to the rural populace. Wed, 01 Jan 2014 00:00:00 GMT http://dr.lib.sjp.ac.lk/handle/123456789/10738 2014-01-01T00:00:00Z http://dr.lib.sjp.ac.lk/handle/123456789/10736 Use of wood characteristics in Identification of selected Terminalia species growing in Sri Lanka Ruwanpathirana, N.D. 250 timber species are being used by the timber industry in Sri Lanka and among them building constructors, furniture manufacturers and wood fabricators are the main consumers. Identification of the trees become very difficult once felled and processed and therefore macroscopic/ microscopic features and physical properties of timber become important. Timber identification is necessary for right use of timber and to check on fraud in timber trading as some timber traders deceive customers by mixing low value timber with high quality ones. Five timber species of Terminalia namely T. arjuna (Kumbuk), T. bellirica (Bulu), T. catappa (Kottamba), T. chebula (Aralu) and T. parviflora (Hampalanda) of the family of Combretaceae were studied anatomically in search of sufficient features to separate one Terminalia sp from the other. Due to the resemblance of wood structure of five Terminalia spp, examination of the transverse sections of wood with a hand lens (×25) does not provide adequate reliable information to differentiate one species from the other for identification. Hence Transverse section (T.S.), radial longitudinal section (R.L.T.) and tangential longitudinal section (T.L.S.) were obtained using the microtome for the anatomical examination. In this study, some important wood anatomical and non-anatomical features were studied according to IAWA (1989). It was found that all Terminalia spp had diffuse porous wood having vessels mainly solitary and occasionally in 2-3 of radial multiples. Mean vessel diameter and vessel diameter range were recorded respectively as 241μm and 172-331μm in T. arjuna, 169μm and 107-204μm in T. bellirica, 240μm and 169-309μm in T. catappa, 115μm and 68-175μm in T. chebula and 124μm and 75-159μm in T. parviflora. Mean vessel frequency were observed as 3 per mm2 in T. arjuna, 4 per mm2 in T. bellirica, 3 per mm2 in T. catappa, 6 per mm2 in T. chebula and 5 per mm2 in T. parviflora. Mean rays frequency, mean ray height and mean ray width were found respectively as 9 per mm, 206μm, 24μm in T. arjuna, 11 per mm, 283μm, 24μm in T. bellirica, 8 per mm, 280μm, 25μm in T. catappa, 13 per mm, 239μm, 31μm in T. chebula and 10 per mm, 235μm, 30 μm in T. parviflora. Ray cell arrangement is mostly uniseriate and occasionally biseriate in T. bellirica, T. parviflora and T. arjuna. Ray cell arrangement is mostly multiseriate and occasionally uniseriate in T. catappa while T. chebula has uniseriate ray cell arrangement. Different type of axial parenchyma types were found in each Terminalia species. T. bellirica had axial parenchyma band (more than three cells wide). T. parviflora and T. catappa had aliform/vasicentric type axial parenchyma which can be differentiated from confluent parenchyma type in T. chebula. Vasicentric (halo) parenchyma types were found mainly in T. arjuna. Finally, it can be concluded that ray cell arrangement and axial parenchyma types can be used together as baseline to distinguish Terminalia spp in Sri Lanka for the purpose of timber identification. Wed, 01 Jan 2014 00:00:00 GMT http://dr.lib.sjp.ac.lk/handle/123456789/10736 2014-01-01T00:00:00Z http://dr.lib.sjp.ac.lk/handle/123456789/10734 Determination of Volatile Constituents of the Essential Oil and Absolute of Nyctanthes arbortristis L. Flowers Grown in the Wet Zone of Sri Lanka Siriwardena, V.S.; Arambewela, L.S.R. The volatile constituents of the essential oil and absolute of Nyctanthes arbortristis L. flowers grown in the wet zone of Sri Lanka were investigated in this study. Hydro-distillation and solvent extraction methods were used to obtain the essential oil and the absolute respectively. The volatile samples were analysed by GC-MS techniques. This study led to the identification of 48 chemical constituents of the essential oil and 4 in the absolute. The essential oil composition was dominated by phytol (32.2%) and methyl palmitate (14.7%). Other well-known volatile constituents such as linalool (0.8%), eucarvone (0.9%), phytone (1.4%), nonadecane (2.3%), methyl myristate (1.1%), cis-9-tricosene (3.6%), n-pentacosane (1.6%) and geranylgeraniol (2.7%) were also identified in the essential oil. The absolute was dominated by butyl acetate (80.8%) followed by phenethyl acetate (1.7%), linalool oxide (1.4%) and 2-butoxyethyl acetate (1.4%). Wed, 01 Jan 2014 00:00:00 GMT http://dr.lib.sjp.ac.lk/handle/123456789/10734 2014-01-01T00:00:00Z