Publications
Reduction of Turbidity, Lead and Coliform of Surface Water Using Chitosan
Rapid dropping groundwater levels and contaminated surface water in the surrounding rivers of Dhaka city has been threatening to the supply of potable water to the resident of city. Turbidity, Heavy metal concentration and Coliform are the major pollution parameters which indicate physical, chemical and biological pollution in the river water. The objective of the present study was to reduce the level of Turbidity, Lead and Coliform in the surface water by Chitosan from shrimp shell. The tests were carried out with coagulation treatment method where Chitosan was used as adsorbent (coagulant aid) which was prepared in the laboratory. Turbidity was found 31.1 to 34.98 NTU in raw water and after treatment with alum-chitosan it was significantly reduced and ranged from 2.0 to 2.2 NTU and the maximum average efficiency was found 93.79%. Lead was found in river water ranging from 0.289 to 0.311 mg/L. These levels were significantly reduced when Chitosan coagulant aid with a maximum average efficiency of 82.87 %. Considerable removal of Total coliforms and Fecal coliform were found after treatment with Chitosan coagulation. Total coliforms and Fecal coliform count were ranged 1.0×105 to 2.0×105cfu/100ml and 1.17×104 to 5.0×104 cfu/100ml, respectively. Up to 99.99 % bacteria were removed after coagulation with chitosan. Using Chitosan for emergency demand response in sudden flood areas or hard to reach areas or where chemical treatment is not available, might be considered as an option for water purificatio
Removal of Ammonia-N Pollution from Surface Water by Sustainable Environmental Techniques
Ship dismantling of Bangladesh is a reason of concern due to its economic values and environmental hazards. This study focuses on the Ship Breaking and Recycling Industry (SBRI) of Bangladesh to assess the environmental impacts. It was done by analyzing the water quality parameters like, Turbidity, Salinity, Electric Conductivity (EC), Dissolved Oxygen (DO), pH, Total Dissolved Solids (TDS), Temperature, Ammonia-Nitrogen, Nitrate–Nitrogen, Phosphate concentrations of inside and surroundings of Ship Breaking Yard. Turbidity ranged from 7.71 to 119 FTU and 4.07 to 41.74 FTU in inside and outside the ship breaking yard, respectively. Salinity ranged from 0.95 to 14.28 ppt and 0.06 to 0.79 ppt in insde and outside, respectively. Value of EC varied from1.75 to 1280 μs/cm in inside and 0.21 to 15.7 μs/cm in outside, DO ranged from 3.77 to 7.94 mg/l in inside and 1.95 to 5.34 mg/l in outside. TDS value ranged from1,280 to 15,340 mg/ l in inside and 74 to 825 mg/l in outside of ship breaking yard. Ammonia-N value ranged from 0.46 to 7.046 mg/l, Nitrate-N value ranged from 0.10 to 6.9 mg/l and Phosphate value ranged from 0.175 to 4.75 mg/l in the analyzed water sample. Magnitude of environmental alteration by establishment of ship breaking industry was assessed by quantifying Environmental impact value of Study area and the value was found as -93, where ecological parameters value was found -72, Physico-chemical parameters value was -70 and human interest value was found +49 which indicate negative alteration on environment.
Water and bottom sediments quality of brackish water shrimp farms in Kaliganj Upazila, Satkhira, Bangladesh
Shrimp culture plays a central part in the fisheries sector of Bangladesh that leads to a significant change in the structure and composition of frozen food export sector. An investigation was carried out to determine physiochemical parameters, nutrients content, bacterial contamination and metal content in shrimp "Gher" (Farms) water and sediments. Physicochemical parameters were analyzed in situ by portable meters. Ammonia, phosphate, bacterial counts, and metals contents were analyzed by Nesslerization, colorimetric and standard microbiological methods and Atomic Absorption Spectrophotometery (AAS), respectively. Except Dissolve oxygen and temperature all other physiochemical parameters were unsuitable for shrimp culture. The concentration of ammonia was 0.384 to 1.5 mg L-1 and the concentration of phosphate ranged from 0.02 to 0.818 mg L-1. In bacteriological analysis, highest levels of coliform were found in the tested samples and total colifom count reached up to 2.04x103 cfu mL-1. Among the tested metals, Cr was highest in water and sediment samples. Concentration of Cr ranged from 0.150 to 0.807 mg L-1 and 1.957 to 3.436 mg kg-1 in water and sediment samples, respectively. A significant difference was observed for the concentration of metals in sediment and water samples. The high concentration of nutrients and metals in shrimp "Gher" water and sediment as well as the presence of pathogenic bacteria in the "Gher" and river water indicated unhygienic environment and the sources of contamination of shrimp "Gher".
Impact of Raw Water Ammonia on the Surface Water Treatment Processes and Its Removal by Nitrification
Impact of raw water ammonia on the treated water quality and removal of ammonia from surface water were studied. Raw water ammonia and physicochemical quality of treated water of Saidabad Water Treatment Plant were analyzed for the period of one year (January through December 2006). The monthly averages of maximum (7.55 mg/l) and minimum (0.34 mg/l) ammonia-N level of the raw water were recorded in March and September 2006 respectively. During dry season raw water containing high concentration of ammonia reacted with chlorine at pre-chlorination step of treatment processes and disrupted the total treatment system. It was found from the study that when the concentration of ammonia was high in raw water the aesthetic characters such as turbidity, colour, taste, odour, alkalinity, total dissolved solids (TDS), conductivity, total chlorine etc. of the treated water were changed significantly. Chemical consumption is increased as a result water treatment costs is increased. To mitigate the above problems of the treated water nitrification was used for the removal of ammonia from raw water. Ammonia removal rate was monitored with some other water quality parameters during the study. In the nitrification process ammonia was removed from raw water very effectively, i.e., maximum about 98% raw water ammonia was removed during the study. Additionally other water quality factors were improved significantly.Keywords: Raw water, Treated water, Raw water ammonia, Water quality, NitrificationDOI: http://dx.doi.org/10.3329/bjm.v24i2.1249 Bangladesh J Microbiol, Volume 24, Number 2, December 2007, pp 85-89
Degradation of Monochlorophenols by Pseudomonas putida CP1 in the Presence of Growth Supplements
Influence of readily degradable additional sources of carbon and nitrogen on the degradation of monochlorophenols by Pseudomonas putida CP1 was investigated. The organism grew on all three isomers of monochlorophenols when supplied as the sole source of carbon and energy. Low concentrations (0.01 to 0.5%, w/v) of yeast extract enhanced degradation of monochlorophenols. The order in terms of rate of removal of monochlorophenols was 4-chlorophenol > 2-chlorophenol > 3-chlorophenol, both in the presence and absence of the growth supplements. The rate of removal of monochlorophenols was highest when carbon:nitrogen (C:N) ratio maintained at optimum level (3:1) with monochlorophenols and growth substrates. The organism clumped when grown in the presence of monochlorophenols alone. The degree of clumping decreased with the addition of growth supplements.
Bacteriological and Physicochemical Analyses of the Raw and Treated Water of Saidabad Water Treatment Plant, Dhaka
Bacteriological and physicochemical parameters of the raw and treated water of the Saidabad Water Treatment Plant were analysed during the period January through December 2004. It was found that during dry season Sitalakhya River water was adversely polluted and most of the bacteriological and physicochemical parameters increased to an alarming level. Total coliform and thermotolerant-coliform counts of raw water were highest in months of January through March and lowest during the months of April through November. Ammonia concentration of the raw water was very high (3.08-7.06 mg/l) during the dry months from January to April that coincided with high (2.57-6.08 mg/l) ammonia contamination in the treated water. The others physicochemical parameters like turbidity, conductivity, total dry solid (TDS), hardness and alkalinity were high during the dry months. The residual chlorine in treated water was always below 0.50 mg/l. The study clearly indicated that the load of coliform increased when the concentration of ammonia was high in raw water that, to some extent, influenced the aesthetic properties of the treated water like turbidity, colour, taste, odour, alkalinity, TDS, etc. In spit of that the treated water could be used for domestic and drinking purposes for most of the year.
Optimisation of pH, Temperature and Carbon Nitrogen Ratio for the Degradation of m-Chlorophenol by Pseudomonas putida CP1
Aromatic pollutants like m-chlorophenol is toxic to the environment and chlorophenol containing a meta- chlorine are more persistent under aerobic conditions than compounds lacking a chlorine substituent in positions meta to hydroxyl group. Therefore, it should be removed effectively from the environment. In order to increase the degradative activity, the optimum conditions for m-chlorophenol degradation by Pseudomonas putida CP1, some physicochemical conditions like pH, temperature and carbon nitrogen ratio for the growth and degradation of most persistent monochlorophenol, m-chlorophenol by the organism was optimised. The pH optimum for m-chlorophenol degradation by the bacterium was between pH 6.5 and 7.0 and the temperature optimum was 30°C for removal activity. Carbon : nitrogen (C:N) ratio of 3:1 was found best for effective removal of chemical oxygen demand (COD) and m-chlorophenol by the bacterium.