Natural and Waste Materials as adsorbents in Oil Pollution Management
By Dulmini Jayewardana | July 1, 2009
Contamination of water with oil substances is a major problem in many industries mainly oil based industries like petroleum refinery industries, soap manufacturing industries and service stations. Sri Lankan coastal zone especially in Southern and Western is susceptible to oil pollution due to oil tankers and other shipping coming to Colombo harbour and a major shipping land existing beyond the shores of Hambantota.
There is a need for technology in managing related risks. So efficient oil-water separation is of prime importance in Sri Lanka and in industrial waste treatment stages, it is often required for operating the wastewater treatment plant efficiently without inhibit the downstream process. Normally large oil globules in wastewater are floating and reduce the Oxygen dissolution thus upsetting the biological treatment processes within the treatment plant. As well as, it may clog the pipe lines in treatment plant and it may impede overall process going on. Many sophisticated technologies are used to treat this wastewater and sometimes it would be prohibitively costly for wastewater treatment. Adsorption is a liable technical option though costly. Hence, the necessity of exploiting low cost adsorbents arises. So natural derived adsorbent or adsorbent coming from waste material is an intensity option to study.
In this study, priority was given to hair disposed from salons, as much of oil adsorbed to hair could be recovered. Then other materials such as coir pith, rice husk, saw dust and tea waste would be used as second adsorption material for removing remaining oil in wastewater treated with hair. Thus the interest is in a two stage adsorption device in oil spill control. The technique will be applicable from oil spill management to more local pollution issues such as service centers and workstations. By optimizing many parameters, such as hair soaking time in oily water, the thickness of oil layer, mixing rate and hair amounts used as adsorbents, the adsorption efficiency would be able to maximize. According to the experiments which were done to optimize the oil layer thickness, adsorption was highly depend on the oil layer thickness. According to the analyzed data, hair adsorbed 96.87%(v/v) of initial oil from the oily water sample which had 6 mm oil layer thickness and 8%(v/v) oil to water ratio. Then 68.75% of initial oil was recovered from hair. hair adsorbed 60%(v/v) of initial oil from the oily water sample which had 2 mm oil layer thickness and 8%(v/v) oil to water ratio. Then 50% of initial oil was recovered from hair. So oil thickness is a function of oil recovery. For large scale usage, the belt type skimmer which is used hair as the adsorption material will be used to recovering oil from water. This skimmer can be operated by using a lever and it will include a mechanism for pressing the hair after adsorbing to recover the oil. The schematic in Fig.(1) gives overall objective of the project.
Oil Separation Steps:
W A J Anurangi, B M P K Amarasinghe, A A P de Alwis.
Department of Chemical & Process Engineering
University of Moratuwa.
Topics: symposium2008 | No Comments »
Comparison of Dry Matter and Nutrient Partitioning in Organically and Conventionally Grown Tea
By Dulmini Jayewardana | July 1, 2009
Organic farming has become increasingly popular in the recent past, with the concerns over unfavourable health and environmental impacts of synthetic inputs used in conventional farming. As a consequence, many tea estates in Sri Lanka have converted to organic cultivation. However, the productivity of tea is reported to decrease upon conversion from existing conventional, inorganic system to organic system.
Comparison of the organic and conventional systems, scientific validation and justification will help in proper establishment of organic tea production systems in the country. Therefore, the objective of this study was to compare dry matter and nutrient partitioning in organically and conventionally grown tea.
The dry matter and nutrient (N, P and K) partitioning was studied in the tea bushes of the ‘TRI OR-CON’ trial at St Coombs Estate, Talawakele. The tea plants of cultivar DT1 have been field- planted in 1996 to compare three organic treatments with conventional: Organic treatments are tea waste, compost and neem oil cake as soil amendments. Bushes were carefully uprooted at each pruning (in the years 2000, 2004 and 2008) and dry matter and nutrient partitioning into different parts was studied.
The partitioning of dry matter and nutrients were not significantly different between the four treatments and between organically and conventionally managed tea bushes during all three pruning times. The highest amount of dry matter was partitioned into the stems (41-67% in different ages and treatments) followed by root system (13-27%). Lowest amount of dry matter was partitioned to the leaves of the bush (9-29%). However, the highest amount of nitrogen and other nutrients partitioned to the flush in all treatments, which ranged between 3.6% and 4.1%. The fallen leaves and branches also contained a significant amount of nutrients and it shows the importance of fallen leaves as well as applying pruning residues for nutrient recycling.
Key words: organic, conventional, pruning, dry matter partitioning, nutrient partitioning
Mohotti A. J.1, Wekumbura W. G. C.2, Damayanthi N.3 and Mohotti K. M.3
1 Department of Crop Science, Faculty of Agriculture, University of Peradeniya, Peradeniya, Sri Lanka
2 Faculty of Agricultural Sciences, Sabaragamuwa University, Belihuloya, Sri Lanka
3 Tea Research Institute, Talawakele, Sri Lanka
Topics: symposium2008 | No Comments »
A Preliminary Assessment of Sustainability of Paddy Cultivation Exposed to Organic and Conventional Systems: A Case Study in Moneragala District
By Dulmini Jayewardana | July 1, 2009
At present due to escalation of cost and availability of artificial inputs, the sustainability status in paddy cultivation is facing negative trends. Moreover owing to continued adoption of conventional and intensive farming practices has lead to serious environmental, Ecological & health concerns in many parts of the country.
Ecological low external input and organic agricultural concepts have proved that increased productivity is possible with less or no environmental pollution and strengthened sustainability indices in paddy production both locally &internationally.
The present exercise explored the existing paddy cultivation systems adopting both traditional &improved varieties under organic and conventional farming techniques in the Badalkumbura Divisional Secretariat of Moneragala District during yala season 2008. Grain yield component analysis of field grown paddy & also soil biological & physical status were measured and compared. Shoot and root growth and dry matter production of early growth were studied in a glass house at TRI Talawakelle. Bio assay was done at TRI laboratory.
Field grown improved varieties showed significantly greater yields under conventional systems than in the organic systems. Interestingly, improved varieties exposed to organic cultivation also performed better than traditional varieties under both conventional and organic systems. Similar trends were observed in the bio assay findings. Irrespective of the system studied though no of tillers per plant and the no of seeds per panicle were low; traditional varieties showed a greater percentage of productive tillers & filled grains per panicle indicating that the less incidence of pest and disease attacks in traditional cultivars. Straw yield was higher in the improved varieties irrespective of the system.
Soil microbial activity measured as CO2 evolution rate was significantly greater under the organic paddy systems. However soil physical properties presented as soil strength did not shoe significant differences. Organic practices excluding artificial inputs and environment friendly cultural practices i.e. organic manure, mulches, non-chemical pest & disease management etc have resulted in improving biological properties of the soil, though the impacts on physical properties would take some time. However, the mean no of earthworm burrows in organic paddy systems were comparatively greater than in the conventional systems.
The Predator: Pest ratio under conventional paddy systems irrespective of the cultivar was comparatively low. Environmental friendly pest and disease management practices under organic systems have shown to benefits natural enemies of economically important insect pests. Also organic cultural systems exhibited a greater species diversity in weed composition; amongst weeds the broad leaf category was higher showing a significantly lower competition and also easy to control.
The results of the preliminary impact assessment of rice cultivations exposed to organic & conventional practices indicated satisfactory positive sustainability indices. However cost: benefit analysis would necessarily asses for the long term sustainability of these systems.
In addition to direct effects there are immense amounts of indirect long term benefits achievable through organic paddy cultivation. Hence long term impact assessment for at least 3-4 consecutive seasons is proposed for better impact assessments.
R. Sandamali 1, Keerthi Mohotti 2
1- Univeristy of Peradeniya, Sri Lanka
2- Tea Research Institute, Sri Lanka
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LOCALLY ISOLATED ENTOMOPATHOGENIC FUNGI TO CONTROL TEA RED SPIDER MITES (Oligonychus coffeae Acarina-Tetranychidae) - A PRELIMINARY LABORATORY STUDY
By Dulmini Jayewardana | July 1, 2009
Amongst the tea pests, mites cause significant damage during dry whether. Their populations are governed by natural enemies whose activity is supported by micro climatic conditions and cultural practices in the tea canopy. The mite damage above thresh-hold levels pose chemical acaricidal treatments but recent restrictions on pesticide residues in made tea warrant alternative methods.
In this study we attempted to isolate entomopathogenic fungi (EPF) acting against tea mites from conducive environments with favorable micro climates and less or no pesticide usage. They were screened under laboratory conditions in view of exploring possibilities in biological control as effective, safer and acceptable methods.
Naturally occurring fungal species from six different tea eco systems reducing populations of the Tea Red Spider Mite (Oligonychus coffeae) were isolated. The laboratory bioassays conducted on mite-infested excised-tea leaves resulted in 65% mortality with the locally isolated fungal isolate ‘HF1’. TRI recommended acaricide, Propargite gave the highest mortality of 75% while, Hirsutella thompsonii and Neem seed extract exhibited lower mortality.
While we report the first record of isolation of EPF from tea mites, we foresee their potentials in managing tea mites as an environmentally safe and effective treatment. The identification, the mode of action against different tea mites and mass propagation of the fungal isolate ‘HF1’are in progress.
Amarasena, P. G. D. S.1, Mohotti, K. M.2 and Ahangama, D.3
1 & 2 Entomology Division, Tea Research Institute, Talawakele, Sri Lanka.
3 Department of Agricultural Biology, Faculty of Agriculture, University of Peradeniya, Peradeniya, Sri Lanka.
Topics: symposium2008 | No Comments »
TRISL Plant protection assures cleanest tea with promise of less Bioaccumulation and biomagnification
By Dulmini Jayewardana | July 1, 2009
Sri Lankan tea are the cleanest tea in the world as far as the chemical residues are concerned. Nurseries are focal points of spread of soil born pathogens such as fungi, bacteria, nematodes and weed seeds to hitherto uninfested areas which will cause future economic damage in agricultural crops. Hence, sterilization of nursery soils and nursery premises are of paramount importance.
Chemical treatment of soil is the most effective means of eradicating these pests. Amongst, agrochemicals, the fumigants are hazardous chemical groups known to cause biological and environmental degradation and worker and animal health.
We fine tuned the methodology of the existing tea nursery fumigation recommendation with Basamid and Metham Sodium in view of assuring reduced non-target effects. The rates of application were brought to half through strengthening the methodology.
The new method resulted in comparatively lower effects on the soil microbial activity and no phytotoxic effects on the plating materials proven through seed germination. The release of the chemical compounds to the environment was minimized and thus reducing the worker and animal exposure. Moreover, the time period for fumigation process was brought from 42 days to 22 days which results in savings on cost, labor and space. Record keeping, displaying sign boards and fumigation schedule were made compulsory.
Although the soil fumigants do not leave any residues in the final food produce, we imposed a Restricted Entry Interval (REI) of 8 days in view of worker and animal safety. The current recommendation is highly beneficial for the small holder and cooperate sector tea growers who practice large scale nurseries. Also, the new certification systems such as Global GAP, Forest Garden Alliance, Natural, Fair trade, ISO, Organic and Biodynamic etc. requesting worker, environment and product safety will be aided tremendously by this the new fumigation methodology.
The method developed for tea could be well adopted in other agricultural nurseries for more benefits.
Keerthi Mohotti
Tea Research Institute, Talawakele, Sri Lanka
Topics: symposium2008 | No Comments »
Environmentally and Worker Friendly and Low Cost Fumigation Methods for Fumigating Tea Nurseries
By Dulmini Jayewardana | July 1, 2009
Nurseries are focal points of spread of soil born pathogens such as fungi, bacteria, nematodes and weed seeds to hitherto uninfested areas which will cause future economic damage in agricultural crops. Hence, sterilization of nursery soils and nursery premises are of paramount importance.
Chemical treatment of soil is the most effective means of eradicating these pests. Amongst, agrochemicals, the fumigants are hazardous chemical groups known to cause biological and environmental degradation and worker and animal health.
We fine tuned the methodology of the existing tea nursery fumigation recommendation with Basamid and Metham Sodium in view of assuring reduced non-target effects. The rates of application were brought to half through strengthening the methodology.
The new method resulted in comparatively lower effects on the soil microbial activity and no phytotoxic effects on the plating materials proven through seed germination. The release of the chemical compounds to the environment was minimized and thus reducing the worker and animal exposure. Moreover, the time period for fumigation process was brought from 42 days to 22 days which results in savings on cost, labor and space. Record keeping, displaying sign boards and fumigation schedule were made compulsory.
Although the soil fumigants do not leave any residues in the final food produce, we imposed a Restricted Entry Interval (REI) of 8 days in view of worker and animal safety. The current recommendation is highly beneficial for the small holder and cooperate sector tea growers who practice large scale nurseries. Also, the new certification systems such as Global GAP, Forest Garden Alliance, Natural, Fair trade, ISO, Organic and Biodynamic etc. requesting worker, environment and product safety will be aided tremendously by this the new fumigation methodology.
The method developed for tea could be well adopted in other agricultural nurseries for more benefits.
Keerthi Mohotti, Nissanka Navaratne, D. D. Liyanage, Deepthi Amarasena, Ajith Prematunga, U. B. Herath, G. P. Udamulla and P. K. Jayawickrema
Entomology and Nematology Division, Tea Research Institute, Talawakele, Sri Lanka
Topics: symposium2008 | No Comments »
Chemical Investigation of Salvinia molesta; a Possible Fertilizer Substitute
By Dulmini Jayewardana | July 1, 2009
Salvinia molesta is considered to be one of the world’s worst aquatic weeds and is an aggressive, competitive species that can impact aquatic environments, local economies, and human health. In favorable environmental conditions plants may be expected to double within about a week. Excessive and rapid growth of giant Salvinia molesta results in complete coverage of water surfaces which degrades natural habitats in several ways. Heavy growth of Salvinia molesta competes with shades and desirable native vegetation. Mats of Salvinia provide ideal habitat for Mansonia mosquitoes, a principal vector of rural elephantiasis in Sri Lanka, and for other mosquito species involved in the transmission of encephalitis, dengue fever, and malaria. Most countries control these species by chemical and biological methods.
The main goal of this research was to study about the chemical composition of Salvinia molesta mainly quantification of total nitrogen, total phosphorous and potassium composition to check the possibility of using it as a component in the fertilizer manufacturing industry. In literature it has been found that this plant has the ability to absorb heavy metals in water. Therefore, it is essential to determine the amount of heavy metals present in the plant mainly because if present these can affect the agricultural aspects and health of living organisms if used as a fertilizer.
The plant samples were collected randomly from a ferry at Hirana, canals at Boralasgamuwa and Panadura areas. They were dried in an oven for twenty four hours under the temperature 60 0C and the dried matter was ground to a fine powder and was stored at 5 0C in air tight containers prior to further analysis. The prepared samples were used to determine the nitrogen, phosphorous, and potassium(N, P, K) content. The N content was determined by standard Kjeldahl method and P content was determined by vanadomolybdophosphoric acid colorimetric method. Atomic absorption spectroscopy was used to determine the K, Cd and Mn content in Salvinia molesta. Comparing these experimental values with the approximate composition of some natural bulky organic fertilizer materials as shown in the table give an idea about the suitability of using salvinia molesta as a fertilizer substitute. Our findings show that Salvinia molesta contains N, P, K in the range 2.3 – 2.6%, 6.4 - 7.8% and 1.3 – 1.8% respectively for the samples collected. Therefore, it is possible to use Salvinia molesta as a good source of nitrogen, phosphorous and potassium in a fertilizer material. The concentration of Mn varies between 98-201 g/g and Cd varies between 3.65-3.95 g/g. Experimental results show that the concentration of Cd is lower than 100 µg/g which is the amount specified to affect the plant growth.
Bulky Organic material N% P% K%
Saw dust 0.2 – 0.2
Oak leaves 0.80 0.35 0.15
Bean Straw 1.2 0.3 1.2
Peanut hulls 1.5 – 0.8
Peat 2.3 0.4 0.8
Alfalfa hay 2.5 0.5 2.0
Keywords: Salvinia molesta, N P K content, fertilizer substitute, heavy metal
Aresha Fernando, Champa D. Jayaweera
Department of Chemistry, University of Sri Jayewardenepura, Sri lanka
Topics: symposium2008 | No Comments »
Feasibility assessments of four plantation timber species
By Dulmini Jayewardana | July 1, 2009
The rapid expansion of the human population has resulted in a tremendous increase in the demand for timber in turn posing a serious threat to natural forest ecosystems. Forest plantations were established primarily to provide an alternative source of timber hence mitigating impacts on natural forests. This study aimed to assess the feasibility of four plantation timber species namely teak, mahogany and two species of eucalyptus that are grown in Sri Lanka. These species are in high demand both in local and export markets. Due to an increasing focus on the depletion of biodiversity the role of forest plantations in facilitating the protection of biota are also investigated.
Three plantation plots of 0.5 ha each of the four timber species, at a harvestable age, were selected in the Kurunegala and Nuwara-Eliya districts. The wood volume produced in each plot was calculated using the dbh and heights of the individual trees. The income generated was calculated using past timber prices and wood volumes produced in each plot. The expenditure incurred in establishment and maintenance was also calculated per plantation for each of the four species taking into consideration the increase in costs of labour and raw materials at times at which different activities occurred in the future.
The mean dbh values (cm) of the four timber species at harvestable ages were teak 35.9, mahogany 44.3, E. microcorys 47.2 and E. grandis 44.3, whilst the mean height values (m) were teak 18.6, mahogany 32.2, E. microcorys 32.9 and E. grandis 32.7. Analyses revealed that the future values of a 1m3 of timber at their respective harvestable ages would be Rs.260000 for teak in 30 yrs, Rs. 160000 for mahogany in 40 yrs, Rs. 112000 for E. microcorys and Rs.75000 for E. grandis in 25 yrs. Based on these values, sawn wood and wood from thinning operations during the growing phase would fetch an income with a Net Present Value of Rs. 1216586 for teak, Rs. 689501 for mahogany, and Rs. 492388 and Rs. 232491 for E. microcorys and E. grandis respectively. The Net Present Value of establishment and maintenance costs were Rs. 201524 for teak Rs. 204373 for mahogany, and Rs. 137709 and Rs. 133676 for E. microcorys and E. grandis. These findings reveal that teak plantations are highly profitable whilst E. grandis appeared to be the least profitable.
With regard to their favourability for biota, teak and mahogany plantations were seen to support a rich assemblage of both flora and fauna. For instance, teak plantations harboured 44 % of plant and 70 % of bird species occurring in natural forests of the same area. Eucalyptus plantations on the other hand were not conducive to faunal species.
The analyses of income, expenditure and profits provided in this study will be useful for entrepreneurs to make assessments regarding the feasibility of forest plantations. The findings reveal that investing in teak plantations and mahogany plantations may generate high profits. Eucalyptus plantations may not be a profitable venture and hence it would be prudent to put the land to some other use. In addition to monetary gains, this study also highlights the role of forest plantations as refuges to both flora and fauna. With increasing threats to the country’s biological diversity, the value of such habitats should not be overlooked.
Vindya Janani de Silva and Mayuri R. Wijesinghe
Topics: Forest Management, Resource Management, symposium2008 | No Comments »
Seed germination and early seedling growth of Brinjal (Solanum melongena) as affected by heavy metals
By Dulmini Jayewardana | July 1, 2009
Soil pollution with heavy metals is a matter of highly concern as more and more Agro-ecosystems are affected. Present investigation was conducted to study the effect of Cu2+ and Ag2+ on seed germination and early seedling growth of Solanum melongena. Pretreated seeds (germination >90%) washed twice with ddH2O were placed on double layered filter papers in Petri dishes. They were treated separately with different concentrations of Cu2+ and Ag2+ and incubated for 10 days under laboratory conditions. Germination was recorded daily, when the radical was appearing through the broken seed coat. The experiment was arranged according to CRD with 3 replicates each contained 25 seeds.
Germination percentage was found to be reduced with the increasing metal concentrations. In the case of Cu2+, a 50% reduction in germination percentage was observed at 40 ppm while at 30 ppm of Ag2+ same reduction was observed implying that toxicity of Ag2+ is severe than that of the Cu2+. The length of the shoot of the seedlings treated with >50ppm Cu2+ was also found to be significantly (p<0.01) lower than that of the lower concentrations (<25 ppm). In the case of Ag2+, both root and shoot length was severely affected even at 20 ppm. Furthermore, some morphological abnormalities in germinated seeds could also be noticed at higher concentrations for both metals. However, the abnormalities were not specific. Results could be concluded that both Cu2+ and Ag2+ affect seed germination of Solanum melongena and the effect of Ag2+ was found to be severe at low concentrations compared to Cu2+.
Key words: Heavy metals, Seed germination, Solanum melongena
Thamali R Dissanayake1, Arunakumara KKIU1 and Walpola BC2
1Department of Crop Science, Faculty of Agriculture, University of Ruhuna,Sri Lanka
2Depertment of Soil Science, Faculty of Agriculture, University of Ruhuna, Sri Lanka
Topics: symposium2008 | No Comments »
Adventitious root induction from in-vitro generated shoots of a selected cinnamon clone (Cinnamomum verum)
By Dulmini Jayewardana | July 1, 2009
Seed propagation is the common propagation method used in cinnamon cultivation. But Cinnamon bears berries only once a year (June- August) and loses viability rapidly during storage. Unevenly matured seeds in a single bunch also require extra precautions to be taken at the harvesting or before sowing. Homogenous plantations would not be established through cross-pollinated seeds. There should be reliable vegetative propagation method/s to overcome these constraints but the main difficulty faced is rooting, thus cinnamon has been recognized as a hard to root crop. The objective of this study was to identify a suitable rooting medium for rooting of in-vitro generated shoots of selected high yielding locally developed cinnamon clone CRS 184 obtained from Cinnamon Research Station, Thihagoda.
Auxiliary and apical buds were directly dipped into 0.1 g/l Ascorbic acid solution at the time of explants collection. Surface sterilization was done washing with running tap water for 30 minutes, 0.1 mg/l Topsin solution for 30 minutes, 5 times with distilled water and 15% NaOCl + 1 drop of teepol for 15 minutes. Outer leaves of the buds were detached and the buds were established in WP medium (Woody Plant Medium) initially for two weeks. Then they were transferred in to Anderson medium supplemented with 3 mg/l BAP (6-benzylaminopurine) and 0.1 mg/l NAA (Napthaleneaceticacid) for proliferation. The shoots emerged from these cultures were used as explants for the root induction trial. In-vitro generated shoots obtained from above procedure were separated and established in MS (Murashige and Skoog’s) media supplemented with different concentrations of IBA (Indole-3-Butericacid) and activated charcoal. The experiment was arranged according to Factorial CRD with 15 replicates. The cultures were maintained at 23± 2 0C with 16 hrs photoperiod light regime (1220 lux). The number of days taken for root initiation and number of roots were observed.
Root initiation was observed 27 days after transferring into the rooting media. Significantly higher frequency of rooting was observed with an average of 2 roots per shoot in the MS media supplemented with 1 mg/l IBA and 1 g/l activated charcoal. Hence it could be concluded that MS media supplemented with 1mg/l IBA + 1g/l activated charcoal facilitates as the best medium for induction of adventitious roots from in-vitro generated shoots of the cinnamon clone CRS 184. Thus this suggests a complete and a successful in-vitro micropropagation protocol for multiplication of the cinnamon clone CRS 184.
Key words: Cinnamomum verum, In-vitro propagation
Thamali R. Dissanayake, S Subasinghe, K M C Fernanado, D L C Kumari and A W K Wellage
Department of Crop Science, Faculty of Agriculture, University of Ruhiuna
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