Faculty Publications

Now showing 1 - 3 of 3

Isolation and identification of Pseudomonas from wastewater, its immobilization in cellulose biopolymer and performance in degrading Triclosan
(Academic Press, 2019) Devatha, C.P.; Narasimhappa, N.
Triclosan (TCS) is a well-known emerging contaminant got wide use in daily use products of domestic purpose, which provides the way to enter the ecological cycle, and is preferably detected in sewage treatment plants. In this study, TCS degrading bacteria (TDB) was isolated and identified from a wastewater treatment plant at the National Institute of Technology-Karnataka, Surathkal (NITK), India. The isolate was reported as Pseudomonas strain by performing 16S RNA Sequencing using BLAST analysis. Bacterial growth depends upon several environmental factors. Hence its growth optimization was carried out by response surface method (RSM) based central composite design (CCD) and validated by the artificial neural network (ANN). The Parameters or inputs used for optimization are pH, time (days), agitation (rpm) and sorbent dosage (?g/L). Experiments were conducted in batch mode to achieve optimum growth of bacteria based on RSM trial runs. The RSM model predictions were in better agreement with the experimental results and it was confirmed by ANN. The deviation lies within ±10% with experimental results compared to ANN for maximum trials. Hence optimized parameters were established and arrived at pH - 7, time - 13 days, agitation - 150 rpm, dosage - 1.5 ?g/L presented 69% removal of TCS. Minimum inhibitory assay of isolated strain was conducted to identify the degradation capacity of TCS and it was found out to be lesser than 0.025 mg of TCS. Later the strain was immobilized in two different matrices. One is biopolymer extracted from cellulose (Water Hyacinth) along with sodium alginate and second is free bacteria with sodium alginate and was made in the form of beads. The removal of TCS by TDB-cellulose-alginate (BCA) and TDB-Alginate (BA) beads were 58% and 30% respectively. Hence it was concluded that BCA beads showed effective removal compared to BA beads. Therefore, isolate can degrade TCS when the concentration ranges from 0.025 mg/L to 5.5 ng/L. © 2018 Elsevier Ltd
Experimental investigation on sludge dewatering using granulated blast furnace slag as skeleton material
(Springer, 2020) Rashmi, R.H.; Devatha, C.P.
The highly compressible nature of sludge and the presence of colloidal particles cause difficulties in sludge dewatering. Reducing the moisture content in secondary sludge is a key factor in reducing the capital costs, operational costs, and transportation costs in wastewater management. This investigation concerned the combined utilization of quicklime and granulated blast furnace slag (GBFS) to improve sludge dewatering. The experimental work included the initial characterization of the sludge and granulated blast furnace slag and evaluation of the dewatering ability of the treated sludge (CST, moisture content, turbidity, zeta potential, and heavy metal and biopolymer contents). Optimization using the Box-Behnken design (BBD) was carried out with various operational parameters, and the best performance was found to be at a pH of 10.2, a dose of 0.34 g/g DS, and a contact time of 14 min. A characterization study was carried out by scanning electron microscopy (SEM) in conjunction with EDS, X-ray diffractometry (XRD), and Fourier transform infrared spectroscopy (FTIR) to confirm the structural features (dense), elemental composition, and the presence of different functional groups. Hence, this study concluded that the use of quicklime with granulated blast furnace slag is suitable for conditioning during sludge dewatering. [Figure not available: see fulltext.]. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
Experimental investigation on sludge conditioning and dewatering using an agricultural biomass coupled with resource recovery
(Academic Press, 2024) Chopade, G.; Devatha, C.P.
In this study, the effect of modified areca husk fibre biochar (MAFB-AlCl3) on dairy sludge conditioning and dewatering along with raw and modified coconut shell biochar (MCSB-FeCl3) was investigated. Further, MgO impregnated biochars of areca husk fibre and coconut shells was carried out to evaluate the performance on phosphate recovery from the diary sludge. The enhancement in sludge dewatering with MAFB-AlCl3 were evaluated experimentally and significant reduction of capillary suction time (CST) (51.6 %), moisture content (18%), zeta potential (1.3 mV) and increased settleability (32.7%) were observed. The sludge conditioning parameters namely dosage (% of dry solids (DS)), rapid mixing time (RMT), slow mixing time (SMT) were optimized by response surface methodology for the modified biochars. Optimum CST (31.51 s) was obtained at dosage (50 % of DS), RMT (9.89 min) and SMT (17.23 min). Results of batch study for phosphate recovery by MgO impregnated biochars (MgB) was found to be 96.6 % and 100 % by MgB of areca husk fibre (MgAFB) and coconut shells (MgCSB) respectively. The morphological characteristics and elemental distribution using field emission scanning electron microscopy (FE-SEM) & energy dispersive X-ray spectroscopy (EDS) reveals the structural change in the sludge particles for the modified biochars as well as for sludge. Hence MAFB-AlCl3, MgAFB and MgCSB is proved to be suitable and an effective candidate for sludge conditioning and dewatering coupled with phosphate recovery in handling the diary sludge. © 2024 Elsevier Ltd

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