Faculty Publications
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Item Laboratory studies were conducted to assess the influence of media related factors such as porosity and pore size and specific surface area on performance of up flow anaerobic biofilters (ABFs). Two simple model of 8 litres capacity up flow anaerobic biofilters (ABFs), one packed with support media granite of size 50 to 40 mm and the other packed with granite of size 25 to 20 mm were installed. The experimental anaerobic biofilters were made of PVC tubes. The hydraulic retention time (HRT) was maintained as 12 hours. The study was carried out for a period of 90 days. The waste treatment performance indicates that the biofilter associated with media of the lesser pore size and porosity with higher specific surface area demonstrated the highest BOD and COD removal 91.03% and 82.50% respectively. Copyright © Enviromedia.(Treatment of domestic wastewater in up flow anaerobic biofilters (using granite as packing material)) Srinikethan, G.; Shrihari, S.; Pradeepan, V.S.2005Item Treatment of domestic wastewater by association of up flow anaerobic and aerobic biofilters(2007) Srinikethan, G.; Shrihari, S.; Pradeepan, V.S.Laboratory studies were conducted to assess the performance of association of up flow anaerobic & aerobic biofilters in treating domestic wastewater. Two simple models of 8 litres capacity, one up flow anaerobic biofilter (AnBF) packed with support media granite of size 20 mm and another up flow aerobic biofilter(ABF) packed with support media granite of size 10 mm respectively were installed. The experimental anaerobic & aerobic biofilters were made of PVC tubes. The hydraulic retention time (HRT) was maintained as 12 hours in anaerobic biofilter and 8 hours in aerobic biofilter. The study was carried out for a period of 90 days. The association of up flow anaerobic & aerobic biofilters demonstrated the average Turbidity, Suspended Solids, BOD and COD removal 96.56%, 96.53%, 95.67% and 90.42% respectively. The waste treatment performance indicates that the association of up flow anaerobic & aerobic biofilters is a promising technique for (sub) tropical countries. Copyright © Enviromedia.Item Prediction of water quality indices by regression analysis and artificial neural networks(2008) Rene, E.R.; Saidutta, M.B.The quality of wastewater generated in any process industry is generally indicated by performance indices namely BOD, COD and TOC, expressed in mg/L. The use of TOC as an analytical parameter has become more cornmon in recent years especially for the treatment of industrial wastewater. In this study, several empirical relationships were established between BOD and COD with TOC using regression analysis, so that TOC can be used to estimate the accompanying BOD or COD. A new, the use of Artificial Neural Networks has been explored in this study to predict the concentrations of BOD and COD, well in advance using some easily measurable water quality indices. The total data points obtained from a refinery wastewater (143) were divided into a training set consisting of 103 data points, while the remaining 40 were used as the test data. A total of 12 different models (Al-A12) were tested using different combinations of network architecture. These models were evaluated using the % Average Relative Error values of the test set. It was observed that three models gave accurate and reliable results, indicating the versatility of the developed models.Item Evaluation of water quality index for drinking purposes for river Netravathi, Mangalore, South India(2008) Avvannavar, S.M.; Shrihari, S.An attempt has been made to develop water quality index (WQI), using six water quality parameters Dissolved oxygen (DO), Biochemical oxygen Demand (BOD), Most Probable Number (MPN), Turbidity, Total Dissolved Solids (TDS) and pH measured at eight different stations along the river basin. Rating curves were drawn based on the tolerance limits of inland waters and health point of view. Bhargava WQI method and Harmonic Mean WQI method were used to find overall WQI along the stretch of the river basin. Five point rating scale was used to classify water quality in each of the study areas. It was found that the water quality of Netravathi varied from Excellent to Marginal range by Bhargava WQI method and Excellent to Poor range by Harmonic Mean WQI method. It was observed that the impact of human activity was severe on most of the parameters. The MPN values exceeded the tolerable limits at almost all the stations. It was observed that the main cause of deterioration in water quality was due to the lack of proper sanitation, unprotected river sites and high anthropogenic activities. © Springer Science+Business Media B.V. 2007.Item Feasibility of gurpur river at Malavoor as a sink for Bajpe town domestic waste disposal - A case study(2009) Babu Narayan, K.S.B.; Kumar, J.P.; Yaragal, S.C.; Shrihari, S.Mangalore is one of the fast growing cities in Karnataka with improved infrastructure taking place in recent days. In view of rapid development in and around Mangalore city, the sub urban or rural areas around the city have started developing at a rapid rate. One such place is Bajpe where the town is growing very fast due to the expansion of activity of Bajpe Airport and upcoming SEZ projects. An attempt has been made to find out the load on River Gurupur, if the Bajpe town domestic waste is assumed to be disposed to River Gurupur at Malavoor bridge point downstream without any treatment. Experiments were conducted to find the parameters used to find out the dissolved oxygen (DO) consumption and replenishment in teh river body using BOD-DO river quality model developed by Streeter-Phelps (1925). Model formulation, analysis and the results obtained are discussed in the paper. Copyright © Enviromedia.Item Petrochemical wastewater treatment using constructed wetland technique(EM International rktem@pn3.vsnl.net.in, 2016) Sudarsan, J.S.; Annadurai, R.; Subramani, S.; George, R.B.Constructed Wetlands are artificially developed ecosystem created to treat the wastewater it was normally like wetlands that occur where water conditions are intermediate between uplands and deep-water aquatic systems. Natural wetlands are capable of improving; the water quality. The ability of natural wetland systems has been recognized for more than 25 years and during this period, the use of engineered wetlands has evolved from a research concept to an accepted pollution control technology. The engineered wetland systems or Constructed Wetland Technology are treatment technologies that mimic natural wetland systems and these treatment techniques were incorporated as components of waste water treatment systems. Two general types of shallow vegetated ecosystems are being used for water quality treatment: (1) free water surface (surface flow) and (2) subsurface flow (vegetated submerged bed) systems. This paper reviews treatment of petrochemical wastewater using constructed wetland. The analysis was done on a lab scale model developed using a PVC tub with a size of 70X40X30 cm and a slight slope of (<1%) between inlet and outlet zones. This technology acts as a natural and low cost treatment facility for wastewater. In this study the plants used were Typha latifolia and Pragmites Australis. The parameters like Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total Suspended Solids (TSS), Nitrogen, Phosphorus, Phenolic Compounds were studied based on APHA guidelines. The pollutant removal mechanism was also reviewed. It was found that the reduction efficiency of BOD, COD, TSS was found to be 90 to 95 % and the Phenolic compound removal efficiency was found to be 65 to 90%. Pollutant removal was highly dependent on retention time and influent concentration and by the action of internal plant communities and microorganisms, water depth. © © EM International.Item Effects of electric potential, NaCl, pH and distance between electrodes on efficiency of electrolysis in landfill leachate treatment(Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2017) Erabee, I.K.; Ahsan, A.; Jose, B.; Arunkumar, T.; Sathyamurthy, R.; Idrus, S.; Daud, N.N.N.This study investigated the effects of different parameters on the removal efficiencies of organic and inorganic pollutants in landfill leachate treatment by electrolysis. Different parameters were considered such as the electric potential (e.g., 24, 40 and 60 V), hydraulic retention time (HRT) (e.g., 40, 60, 80, 100 and 120 min), sodium chloride (NaCl) concentration (e.g., 1, 3, 5 and 7%), pH (e.g., 3, 7 and 9), electrodes materials [e.g., aluminum (Al) and iron (Fe)] and distance between electrodes (e.g., 1, 2 and 3 cm). The best operational condition of electrolysis was then recommended. The electric potential of 60 V with HRT of 120 min at 5% of NaCl solution using Al as anode and Fe as cathode (kept at a distance of 3 cm) was the most efficient condition which increased the removal efficiencies of various parameters such as turbidity, salinity, total suspended solids (TSS), total dissolved solids (TDS), biochemical oxygen demand (BOD), chemical oxygen demand (COD) and heavy metals (e.g., Zn and Mn). The higher removal percentages of many parameters, especially COD (94%) and Mn (93%) indicated that the electrolysis is an efficient technique for multi-pollutants (e.g., organic, inorganic and heavy metals) removal from the landfill leachate. © 2017 Taylor & Francis Group, LLC.Item The combined effects of carbon/nitrogen ratio, suspended biomass, hydraulic retention time and dissolved oxygen on nutrient removal in a laboratory-scale anaerobic–anoxic–oxic activated sludge biofilm reactor(IWA Publishing, 2018) Manu, D.S.; Thalla, A.K.The current trend in sustainable development deals mainly with environmental management. There is a need for economically affordable, advanced treatment methods for the proper treatment and management of domestic wastewater containing excess nutrients (such as nitrogen and phosphorus) which can cause eutrophication. The reduction of the excess nutrient content of wastewater by appropriate technology is of much concern to the environmentalist. In the current study, a novel integrated anaerobic–anoxic–oxic activated sludge biofilm (A2O-AS-biofilm) reactor was designed and operated to improve the biological nutrient removal by varying reactor operating conditions such as carbon to nitrogen (C/N) ratio, suspended biomass, hydraulic retention time (HRT) and dissolved oxygen (DO). Based on various trials, it was seen that the A2O-AS-biofilm reactor achieved good removal efficiencies with regard to chemical oxygen demand (95.5%), total phosphorus (93.1%), ammonia nitrogen concentration (NH4þ-N) (98%) and total nitrogen (80%) when the reactor was maintained at C/N ratio of 4, suspended biomass of 3 to 3.5 g/L, HRT of 10 h, and DO of 1.5 to 2.5 mg/L. Scanning electron microscopy (SEM) of suspended and attached biofilm showed a dense structure of coccus and bacillus bacteria with the diameter ranging from 0.3 to 1.2 ?m. The Fourier transform infrared (FTIR) spectroscopy results indicated phosphorylated macromolecules and carbohydrates mix or bind with extracellular proteins in exopolysaccharides. © IWA Publishing 2018.Item Assessment of coastal water quality along south west coast of India using multile regression analysis on satellite data(National Institute of Rural Development Rajendranagar Hyderabad 500 030, 2018) Jose, D.M.; Mandla, V.R.; Subbarao, S.S.V.; Rao, N.S.; Moses, S.A.The coastal waters being the ultimate receiver of all the wastes, shows a declining trend in its quality. It is of immense importance to know the extent of pollution for its monitoringandmanagemenlMeasurementofdissolvedoxygen (DO), biologicaloxygen demand (BOD), pH and fecal coliform (FC) are vital in water quality monitoring and assessment studies. Usually these parameters are determined by analysing water samples collected from various locations. Since this is tedious and expensive, it is limited to small scales. In this paper, an effort has been made to quickly assess the quality of coastal waters of Kerala directly from the satellite imagery by estimating National Sanitation Federation Water Quality Index (NSFWQI) along with DO, BOD, pH and FC. Multiple linear regression is used to develop statistically significant models using Sea Surface Temperature (SST) and Remote Sensing Reflectance (Rrs) from Moderate Resolution Imaging Spectroradiometer (MODIS) and in-situ data available on DO, BOD, pH and FC. The models when validated showed good correlation between in situ values and predicted values with r values ranging from 0.73 (p=0.001) for DO to 0.89 for NSFWQI (p=0.018). Spatial maps are generated showing the distribution of these parameters along the coast. The parameters in the study are checked to see if they are in compliance with the standards. The study gives models to estimate the daily distribution of these parameters along the coast using MODIS data. Thus, appropriate control measures could be adopted to limit the effect on susceptible rural population. © 2019 JPR Solutions. All rights reserved.Item Spatial and temporal variations in river water quality of the Middle Ganga Basin using unsupervised machine learning techniques(Springer Science and Business Media Deutschland GmbH, 2020) Krishnaraj, A.; Deka, P.C.In this study, cluster analysis (CA), principal component analysis (PCA) and correlation were applied to access the river water quality status and to understand spatiotemporal patterns in the Ganga River Basin, Uttara Pradesh. The study was carried out using data collected over 12 years (2005–2017) regarding 20 water quality parameters (WQPs) covering spatially from upstream to downstream Ankinghat to Chopan, respectively (20 stations under CWC Middle Ganga Basin). The temporal variations of river water quality were established using the Spearman non-parametric correlation coefficient test (Spearman R). The highest Spearman R (?0.866) was observed for temperature with the season and a very significant p value of (0.0000). The parameters EC, pH, TDS, T, Ca, Cl, HCO3, Mg, NO2 + NO3, SiO2 and DO had a significant correlation with the season (p < 0. 05). K-means clustering algorithm grouped the stations into four different clusters in dry and wet seasons. Based on these clusters, box and whisker plots were generated to study individual clusters in different seasons. The spatial patterns of river WQ on both seasons were examined. PCA was applied to screen out the most significant water quality parameters due to spatial and seasonal variations out of a large data set. It is a data reduction process and a more conventional way of speeding up any machine learning algorithms. A reduced number of three principal components (PCs) were drawn for 20 WQPs with an explained total variance of 75.84% and 80.57% is observed in the dry and wet season, respectively. The parameters DO, EC_ Gen, P-Tot, SO4 are the most dominating parameters with PC score more than 0.8 in the dry season; similarly, TDS, K, COD, Cl, Na, SiO2 in the wet season. The different components of water quality monitoring, such as spatiotemporal patterns, scrutinize the most relevant water quality parameters and monitoring stations are well addressed in this study and could be used for the better management of the Ganga River Basin. © 2020, Springer Nature Switzerland AG.