Browsing by Author "Rajapaksha, R.M.G.N."

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    Applicability of Brown Seaweed Species (Sargassum crassifolium) for Treating Lobster Farm Wastewater
    (Uva Wellassa University of Sri Lanka, 2021) Pirashanthy, K.; Rajapaksha, R.M.G.N.; Bambaranda, B.V.A.S.M.; Nirooparaj, B.; Chirapart, A.
    Wastewater generation in aquaculture farms, including all lobster culture practices is a serious issue in the industry. The present study was carried out at lobster farm located at Northern Province in Sri Lanka. Approximately 756,000 L of wastewater is generated on this farm annually and discharges wastewater without proper treatment to the natural environment. The wastewater discharged from lobster farm consists of organic and inorganic chemical components that can be caused potential environmental problems. Present study focused to investigate applicability of Brown seaweed Sargassum crassifolium biomass to efficient removal of nutrients (nitrogen and phosphorous) from the lobster farm wastewater. The Sargassum crassifolium is an abundant species in Northern Province, Sri Lanka. Seaweed biomass optimization was performed using three different seaweed biomasses, viz 20 g, 30 g and 40 g and 20 g (1 g L-1) identified as the efficient seaweed biomass. Wastewater initial physicochemical parameters pH (7.9 ± 0.02), Temperature (29 ± 0.04 ⁰ C), Salinity (36 ± 0.03 ppt), Dissolved Oxygen (3.58 ± 0.02 mg L-1), Biological Oxygen Demand (115 ± 0.05 mg L-1), Ammonia (1.37 ± 0.01mg L-1), Nitrite (0.143 ± 0.00 mgL-1), Nitrate (0.243 ± 0.01 mg L-1) and Phosphate (4.760 ± 0.02 mg L-1) were analyzed using the standard methods. Then wastewaters were collected from the farm and transferred to six glass tanks of 50 L capacity each. The seaweed was used at 1 g L-1 density in each tank except in the control tank. Complete randomized design was used to the experiment. Three replicates were used. Ammonia, Nitrite, Nitrate and Phosphate were analyzed once in three days from beginning to the end of the treatment period (28 days) to investigate the initial wastewater qualities and quality changes after Phycoremidiation. After phycoremidiation physiochemical parameters pH (7.4 ± 0.06), Temperature (29 ± 0.03 ⁰ C), Salinity (36 ± 0.05 ppt), Dissolved Oxygen (5.74 ± 0.04 mg L- 1), Biological Oxygen Demand (95 ± 0.03 mg L-1) were analyzed in wastewater. Sargassum crassifolium removed 1.19 ± 0.34 mg L-1 of Ammonia, 0.12 ± 0.03 mg L-1 of Nitrite, 0.14 ± 0.04 mg L-1 of Nitrate and 2.40 ± 0.72 mg L-1 of Phosphate. Nutrient removal amounts were significantly differed (P<0.05) between control and treatment tank. The weight gains Sargassum crassifolium during the study period was of 8.7 g thus, the seaweed has been utilized the nutrients present in the discharged waste waters. The results of the study concluded that the nitrogen and phosphorus in the lobster farm waste waters, can be effectively removed through Sargassum crassifolium. Keywords: Lobster, Sargassum crassifolium, Seaweed, Phycoremidiation
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    Determination of Efficiency of Crab Shell Powder for the Treatment of Fish Waste Water
    (Uva Wellassa University of Sri Lanka, 2013) Wijesundara, A.P.; Rajapaksha, R.M.G.N.; Jayamanne, S.C.; Fonseka, W.R.K.
    Water is the most important and basic requirement for life on earth. However, only about 1% of the world’s water can be used for the human consumption. Seafood processing is one of the major industry, which threatens the quality of natural water bodies due to its composition (Zvezdov and Zvezdova, 2010). It elevates the Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Fats, Oil and Grease (FOG) in natural waters and causes eutrophication (Tahir et al., 2013). Some toxic residues may be produced as by-products due to chemical reagents used in conventional wastewater treatment methods, which are toxic for human health and the environment (Gaherwar and Kulkarni, 2012). Hence the utilization of shellfish waste has been proposed as a low cost and eco-friendly wastewater treatment method to solve environmental problems and as a waste management alternative to the masses of shellfish wastes (Muhaemin, 2005). Shells of Portunus pelagicus were used in this study to examine its effectiveness as an adsorbent in treatment of fish processing wastewater. Methodology Crab shells collected from Alpex Marine (pvt)were cleaned and dried at 100 °C for 8 hours using MICHCHEL tray dryer and crushed then sieved to raw powder with 0.1-0.5mm particle size range.50 g of raw powder was heated at 950 °C for three hours in a muffle furnace ( Xy- 1100x-L) to prepare heat treated crab shell powder. Chitin and Chitosan were collected from Industrial Technology Institute laboratory. Wastewater samples were collected from Ceylon Fresh Seafood(pvt) and initial COD (Golterman and Clymo, 1970), pH, temperature (MARTINI pH 55 pH meter), Total Dissolved Solid (TDS) (EUTECH CON 510 TDS meter) and turbidity (TN-100 turbidity meter)values of the wastewater were recorded. The first experiment was done to find out best powder dosage and 5.0 gl dosages were taken from each powder type then placed into 250 ml glass beakers. Then 100 ml of fish wastewater was added to each beaker and stirred for 2 minutes Three replicates were used for each treatment. A beaker containing wastewater only was used as the control. After 24 hours final pH, temperature, TDS, turbidity and COD of treated wastewater were measured using AOAC (1985). During the second experiment initial pH value of the wastewater samples were adjusted to pH 5, 7 and 9 by adding 0.1 M HCl or 0.1 M NaOH. Then selected the best powder dosage from the experiment 1 was used for the second experiment and same procedure was followed to find best pH value which allows highest COD reduction. In the third experiment pH of the wastewater was maintained at the best pH value which was selected from the second experiment. Combinations of Chitosan and heat treated crab shell powder was used in1:1, 1:2, 1:3, 3:1 and 2:1 ratios. Total powder weight in each combination was equal to the best powder dosage which was selected from the first experiment. After 24 hours same procedure was followed as in the early experiments. Finally best powder combined ratio was selected based on highest COD reduction. Significant effect of each treatment was analysed by analysis of variance (ANOVA) using General Linear Model (GLM) procedure of Minitab 16 statistical package.
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    Spatial and Temporal Variation of Physico-chemical Parameters of Water in Badulu-oya Upper Catchment Area
    (Uva Wellassa University of Sri Lanka, 2016) Rajapaksha, R.M.G.N.; Edirisinghe, U.; Jayawardana, J.M.C.K.; Jayamanne, S.C.
    Upper catchment area of Badulu-oya, is one of the natural lotic systems, where its pristine status is getting ruined as a result of excessive pressure exerted due to various anthropogenic activities. The present study was planned to study the spatial and temporal variation of physico-chemical parameters of water in the Badulu-oya upper catchment. Covering a 20 km distance, 12 study locations were selected, which included 4 tributaries that confluenced to the main river and possessed different land use patterns as well as urbanized and relatively less disturbed locations. Thirteen physico-chemical parameters were analysed for one year period, monthly. General Linear Model was used to identify the significance differences of spatial and temporal variations of water quality. Correlations of water quality parameters with respect to their spatial and temporal variations were analysed by Principle ComponentAnalysis using PRIMER 7 software. Throughout the study period, water temperature, turbidity, EC, TDS, apparent colour, pH, DO, BOD„ total alkalinity, total hardness, nitrate, nitrite and orthophosphate contents fluctuated between 20.9 —30.4°C, 2.27 —159 NTU, 40.2 —198.5 p.S/cm, 20.1 — 99.5 ppm, 4 — 454 PtCo., 5.6 - 8.64, 8.4 —13.4 mg/L, 0.28 — 6.32 mg/L, 34 —136 mg/L CaCO3, 34 —134 mg/L CaCO3, 0.5 — 17.5 mg/L, 0.001 — 0.045 mg/L and 0.11 — 0.95 mg/L respectively. Five principle components (PC) were obtained with Eigenvalues >1 summing almost 76% of the total variance in the data set. The PC1 represented 24% while PC2 represented 20 % of the data variability. Water temperature, pH, EC, TDS, total alkalinity and total hardness negatively correlated with PC1, while BOD and NO3", EC, TDS, alkalinity and hardness negatively correlated with both PC1 and 2. Study revealed that water quality of Badulu-oya upper catchment is still under the recommended surface water quality standards which support healthy aquatic life. Keywords: Catchment, Water quality, Spatial, Temporal
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    Study of the Diversity of Benthic Macro-Invertebrates at Panadura Estuary in Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2016) Weerasooriyagedara, M.S.; Hettige, N.D.; Amarathunga, A.A.D.; Rajapaksha, R.M.G.N.; Jayamanne, S.C.; Weerasekara, K.A.W.S.; Maddumage, M.D.S.R.; Azmy, S.A.M.; Wickramaarachchi, W.D.N.; Jayawardane, J.K.P.C.; Narangoda, S.R.C.N.K.
    Panadura estuary situated in the western province in Sri Lanka where Bolgoda lake opens into Indian Ocean harbours a lot of aquatic biodiversity. Therefore, main objective of this study was to identify the diversity of benthic macro-invertebrates, to assess the correlation between physico-chemical parameters and macro-benthic invertebrate diversity and to evaluate the pollution level in the estuary with respect to the diversity of benthic macro-invertebrates in Panadyra estuary. Both sediment and bottom water samples were obtained from 19 randomly selected sampling locations in Panadura estuary. Collected Benthic macro-invertebrate samples were wet sieved and identified using standard identification keys. The diversity of benthic macro — invertebrates was determined by using Shannon —Weiner index, richness was calculated using Margalef s index and the health status of the estuary was determined by using Pollution Tolerance Index. Similarities among macro-benthic communities at different locations were determined by using Bray — Curtis similarity coefficient. This study also attempted to determine the physico — chemical determinants that govern the spatial variation. Individuals of 1708 species of macro benthos belonging to 14 families were identified. Planobidae, Haminoidae and Veneridae were the most abundant families. The lowest species richness and diversity was reported at PE6 while highest species richness and diversity was reported at PE7. The sampling locations were separated into several clusters based on the diversity of macro benthos. The major physico-chemical parameters which had effect on the diversity of macro benthos were Biochemical oxygen demand and nitrate nitrogen concentration. Shannon Weiner diversity index in each location at Panadura estuary was in between 2 — 3 and Pollution Tolerance Index in each location was lower than 20. Both these indices confirmed that the aquatic health of Panadyra estuary was in poor condition. Key words: Benthic macro- invertebrates, Diversity, Pollution Acknowledgements: The authors are thankful to the National Aquatic Resources Research and Development Agency for providing funds to carry out this research project
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    Study of water quality changes and growth of cultured edible oysters (Crassostrea madrasensis), culture sites at Gagewadiya and Kandakuliya in Puttlam district
    (Uva Wellassa University of Sri Lanka, 2015) Wijayananda, H.I.; Rajapaksha, R.M.G.N.; Liyanage, N.P.P.; Kithsiri, H.M.P.; Corea, S.; Rupika, G.R.H.; Fernando, U.; Dejager, T.
    Global bivalve production from aquaculture has consistently increased over the years. Sri Lanka is a country which has vast natural resources and suitable environmental conditions for aquaculture. Therefore it has a great potential for develop and contribute to national fish and shellfish production. Although the bivalve industry is highly developed industry in East Asian region finfish and shellfish, specially mollusk and sea cucumbers cultures are at very initial stage in Sri Lanka (Samarasundera, 2010).Sustainable utilization of unexploited high demand finfish and shellfish species are a good alternative to develop the industry. Oysters are nutritious, still unexploited fishery resources in Sri Lanka. Which has good export demand worldwide. Although Sri Lanka have required resources naturally to uplift the industry in large scale, lack of information, limited supply of seeds and lack of trained personals are act as major constraints (FAO, 2006). The success of bivalve culture greatly depends on suitable environmental factors that ensure both optimal growth and quality as well as ensure food safety (FAO, 2006). Kandakuliya and Gagewadiya areas are blessed with natural oyster resources but which are not used commercial scale at present. Therefore the two locations have significant possibility to conduct oyster culture in large scale which providing self-employment opportunities for fisher communities. The study of water quality changes and growth of edible oysters (Crassostrea madrasensis) culture, sites at Gagewadiya and Kandakuliya in Puttlam district was carried out to investigate the possibility of establish these culture in commercial scale. Methodology The research project was conducted in two experimental sites (Gagewadiya and Kandakuliya), locates in Puttlam district, Sri Lanka. Field data were collected during October 2013 to July 2014from pre- establish two experimental culture sites. There were four sampling points in each site separately K1, K2,K3, K4in Kandakuliya and G1, G2, G3, G4in Gagewadiya. Water quality data, growth data and phytoplankton data were collected each site separately. Water quality and phytoplankton data were collected twice a month, and growth data were collected once a month during the studied period. Temperature, pH, salinity, transparency were recorded as onsite measurements. Further analysis were conducted for nitrite, nitrate, phosphate and ammonia using DR-4000U spectrophotometer according to standard procedures of Parsons et al., 1984. Unionized ammonia levels were calculated using total ammonia levels. Phytoplankton samples were collected using phytoplankton net (50 µm mesh size).The samples were examined under light microscope and identified to genus level using identification keys (Newell and Newell, 1963; Rebert, 2003; Swadling, 2008; Verlencar and Somshekar, 2004).Length (distance between the end of umbo and the ventral shell margin) and width (length at the widest axis of the body) were taken as growth parameters. Twenty five C. madrasensis organisms were used to take measurements from each site separately, for the growth study. Both primary and secondary data were used to analysis. Secondary data were taken from IDRC oyster research and culture programme. Minitab 16 statistical package was used to data analysis. All data were analyzed statistically using one way ANOVA (Turkey test) for all selected locations. Person product movement correlation coefficient analysis was done between water quality parameters and growth of oysters to find whether there were significant relationship between those variables.