Wijesundara, A.P.Rajapaksha, R.M.G.N.Jayamanne, S.C.Fonseka, W.R.K.2022-02-232022-02-232013http://www.erepo.lib.uwu.ac.lk/bitstream/handle/123456789/8428/62-AQT-Determination%20of%20Efficiency%20of%20Crab%20Shell%20Powder%20for%20the%20Treatment%20of%20Fish%20.pdf?sequence=1&isAllowed=yWater 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.enAnimal SciencesAquaculture and FisheriesAquatic ResourcesFishWaste Water TreatmentOther