• The Topographic map (from SRTM), digital elevation model (from SRTM), geology & geomorphology map (from GSI), drainage map (from toposheet, DEM), Stream order map, land use land cover map (from LISS-III, 2017), Thiessen polygon map (from rain gauge stations) were prepared and used as layers in integrated flow modelling. 
• Demarcation of various quarries, old channels in Chennai region were carried out with Satellite imagery and toposheets and possible interventions were noted based on the base maps prepared in ArcGIS 10.4 software package. 
• Volume of the quarries, water availability in quarries and water bodies, surface and groundwater level in different locations and elevations were assessed, thus possible links and diversions were conceptualized. 
• Rainfall occurrence and variation studies for the Adyar sub-basin for the past 39 years were analyzed using the homogeneous and autocorrelated rainfall records procured from IMD and PWD. 
• a box-model approach for reservoir operation (Chembarambakkam reservoir) under extreme conditions has been developed and the performance was ascertained using the correlation coefficient and Nash–Sutcliffe efficiency with an average error estimation of 15% and 25% in water level, 21% and 18% in outflow simulation, respectively. 
• The R-R model for the Chembarambakkam sub-catchment was set up using MIKE11 NAM package and the performance of this model was ascertained using the Coefficient of determination and water balance error with 0.72 and -10% respectively. 
• The Chembarambakkam reservoir (3.65 TMC) and the three abandoned quarries (1 TMC approx.) at the downstream part of the modelled Chembarambakkam sub-catchment were used for distributing and storing the simulated discharge to achieve improved water storage, reduced inundation and better water supply. 
• The flow model of Adyar watershed using MIKESHE package has been set up. Calibration and validation are in progress. 
• The daily rainfall data, projected under RCP 4.5 and 8.5 from RegCM 4.4 prepared by IITM, Pune was acquired for the Chennai region and was downscaled and bias-corrected by linear scaling method using IMD daily rainfall data. The projected rainfall data until 2100 will be used for further simulations of the model. 
• The water samples from abandoned quarries, lakes, ponds and groundwater were collected and analyzed periodically once in three months
•  Collection of real time data of river discharges at critical locations across Adyar River and Kosasthalaiyar River. 
• Evaluation of the hydrological response of the catchment due to the application of different combinations of SUDS using SWMM. 
• Vadose zone modelling using HYDRUS -1D to simulate the infiltration based SUDS to combat the limitations of SWMM in SUDS representation through SWMM-HYDRUS coupling. 
• Development of the SWMM-HYDRUS-1D coupled model using pySWMM and phydrus to simulate hydrological response of rainwater harvesting, permeable pavement, infiltration trench, infiltration basin and recharge shaft for IIT Madras campus, India. 
• Formulation of methodology for strategizing a regional level planning of SUDS that would facilitate holistic water resource management for the basin. 
• Development of modules for SWAT model formulation of LIDs using MATLAB to facilitate river basin scale decision making. 
• LID modules for bio-retention cells, rain gardens, green roofs, permeable pavements, infiltration trenches and swales were formulated and the verification of the same is going on using HYDRUS 1D model. 
• Conceptual model for recharge shaft was formulated and the development of the module is completed. 
• Hydrological and hydraulic modelling to estimate the impact of traditional water storage tanks to control flood inundations in the Pallikaranai Marshland. 
• Data sets that represent critical watershed parameters for site suitability analysis of LID components were collected from various sources.
• Methodology for site suitability analysis of LID components using Multi-Criteria approach was formulated. 
• Thematic data layers viz., depth to bedrock, drainage density, geology, geomorphology, land use & land cover, lineament density, profile curvature, rainfall, slope, soil, Topographic Position Index (TPI), and Topographic Wetness Index (TWI) was created in GIS. 
• Preliminary site suitability map of detention basin using Analytical Hierarchy Process (AHP) was prepared for Chennai basin using 11 of 14 thematic layers. 
• Collection of rainfall data and calibration of time series predictive model developed at the study areas, and tracking the change in trend, cyclicity and seasonality 
• Spatio-temporal hydrological modeling at University campus and estimation of water quality contours
• Assessment of water flow pattern variation through SWAT modeling and exploration of improved water utilization approach. 
  

•  Development of portable and low-cost techniques for detecting and removing trace pollutants. For this, a traditional method such as paper strip sensor and carbon-based adsorbents from waste have been tested. At the same time, two low-cost green adsorbents were made from agriculture and sewage sludge to remove emerging contaminants. A risk assessment model was developed to characterize the hazard efficiency of micropollutants in the Cauvery river basin. Additionally, the application of MOF for sorptive and electrosorption removal of phosphate was teste
• Degradation of three dyes (methylene blue, methyl orange and basic fuchsin) was studied in pulse power plasma technology was completed 
• To utilize the pulse in activation of catalyst was studied to improve the efficiency of technology and to reduce the cost of the treatment process 
• Effects of various parameters such as input voltage, initial dye concentration, treatment time etc was studied to find the optimized treatment condition 
• The degradation mechanism and cost of treatment is being carried out to understand the feasibility of such process in dye degradation 
• The synthesis of triptycene based polymers was completed to use for sorptive removal of pharmaceuticals (diclofenac and carbamazepine) from wastewater 
• Adsorption studies and the effect of ultrasonication is being studied 
• The model-based analysis will be carried out to optimize the various parameters involved 
• Characterization of the polymers is carried out to find out the mechanism behind the sorption 
• Nanocellulose reinforced organo-inorganic nanocomposite for synergistic and affordable defluoridation of water and an evaluation of its sustainability metrics 
• Sensors and Kits for Water Quality Monitoring 
• Scalable drop-to-film condensation on a nanostructured hierarchical surface for enhanced humidity harvesting 
• The properties of the electrochemical cell (adopted with three-electrode configuration) was measured by Electrochemical impedance spectroscopy (EIS) and cyclic voltammogram (CV). This work is in progress now 
• A Covalently Integrated Reduced Graphene Oxide–Ion-Exchange Resin Electrode for Efficient Capacitive Deionization 
• Industrial Utilization of Capacitive Deionization Technology for the Removal of Fluoride and Toxic Metal Ions (As3+/5+ and Pb2+) 
• Low-cost microfluidic platform for multi-analyte assessment of water quality 
• The standalone AgNC film showed good stability in water, and the system could release silver ions of the required quantity till 500 cycles in distilled water and 250 cycles in surface and groundwater 
• The AgNC films subjected to various water conditions were investigated with microscopic and spectroscopic tools 
• The spent AgNC films were recycled to form composite termed as "G Plug," and it is disposed of as a sealant to heal micro-cracks in the concrete 
• The G Plug has demonstrated excellent potential to seal the micro-cracks in the concrete and enhanced the compressive strength of the concrete cubes that are subjected to damage 
• The interaction between G Plug and the cement were studied using spectroscopic and microscopic characterization tools 
• The concrete cubes sealed with G plug was evaluated for the potential leaching of Ag ions via modified TCLP analysis, and the results showed that the release of Ag ions is around 150 times lesser than the permissible limits given by RCRA 
• Based on the results, a manuscript titled "Chitosan-based nanopolymer composite as a sustainable point-of-use reservoir of silver ions: Water disinfection and safe disposal" is being prepared 
• Methods of coating nanocomposite film on various surfaces for developing a PoU system were studied. Among various methods, (i) coating on a glass substrate after pretreatment at high temperature and pressure in the presence of Tri-sodium citrate and (ii) packed bed reactor employing nanocomposite beads were found to be feasible 
• The coating of nanocomposite coated citrate-functionalized glass plates is found to be hydraulically stable 
• The studies showed approximately 100% removal of U(VI) [5 mg/L]. Isotherm studies showed a maximum adsorption capacity of 183 mg/g at 30 oC 
• An article titled "A critical review of uranium contamination in groundwater bodies: Treatment and safe disposal" is accepted with minor revisions in the Journal Science of Total Environment 
• Article titled "Chitosan immobilized granular FeOOH-MnXOY bimetal-oxides nanocomposites for the adsorptive removal of lead from water" is accepted with minor revisions in the Journal of Environmental and Chemical Engineering 
• The electronic components are procured locally and assembled. The instrument comprises of linear voltage regulator powered by a 12V battery, which has been fed into the switching voltage converted to 5V. This is to provide the differential voltage at the potentiostatic unit. An integrated circuit LM2902N has been used to connect the three electrode system comprises of working, counter, and reference electrode. An LED display is also integrated into the device, which indicates the changes in the potential and has been proportional to the concentration of metal ions present in the system. The electrode was constructed using the carbohydrazide and thymine functionalized graphene oxide drop cast on the screen-printed carbon electrode surface. Further, fabricated electrodes were used for the electrochemical sensor using the handheld device developed by us. Initially, the electrode was validated for sensing using the electrochemical workstation. The fabricated handheld device was evaluated for sensing chromium(VI) and control samples. The electrode senses the metal ions by indicating the potential changes corresponding to the specific metal ion. This handheld electrochemical device can use for on-site detection of chromium (VI) in an environmental water sample. Further, evaluation of the device is in progress and the total materials cost of the device is around Rs.1000/-.

• Graphene oxide (GO) synthesized as a building block for the reporter and grafted are L-Cysteine functionalization. The grafted and graphene oxide are connected covalently via C-S conjugation. The solid-state nuclear resonance spectroscopy (ss-NMR) data shows the functionalization of graphene oxides (Figure 1). It confirms the attachment of L-cysteine on the graphene oxide layer. Further evaluation of the materials for sensing is in progress.
  Sample Control.

• For colorimetric sensing, the following molecules were synthesized, characterized and the sensing studies are being evaluated.

• The toxicity studies of the synthesized compounds were evaluated using MTT assay.
• Human skin origin, HaCaT and Kera cell lines as well as A549 and MCF 7 cancer cell lines were used for the study.
• Fabrication conditions for molecular cage derived crystalline covalent organic framework based free-standing film for nanofiltration.
• The recent research findings on broad-spectrum micropollutant removal from water published in ACS Appl. Mater. Interfaces has been shared with the media team. The news is going to be covered with frontline print media.
• Testing of pristine and sulfonated HCPs for real-time removal of pharmaceuticals found in Indian surface water in collaboration with Prof. Ligy Philip Group, IITM
• We have successfully developed a simple, greener, and cost-effective way to synthesize 2D and 3D GBM from the extract and fibre of Drepanostachyum falcatum. At low temperatures (150 °C), the 2D-MDGOs are extremely hydrophilic and readily bluish fluorescent under UV light of 365 nm. This material is biocompatible and nontoxic, whereas the synthesized 3D-GNR at high temperature (300 °C) is hydrophobic and has a 3D network-like structure. This 3D-GNR shows its excellent behavior for the removal of cationic dyes, i.e., MB. Therefore, the 3D-GNR can act as a promising candidate in the field of water purification.
• We have submitted the manuscript titled "Green and cost-effective synthesis of 2D and 3D Graphene-based nanomaterials from Drepanostachyum falcatum for Bio-imaging and Water purification applications" to a reputed journal, "Chemical Engineering Journal Advances." The manuscript is under revision.
• In addition, in this time frame, we successfully synthesized graphene-based sponge for oil water separation, and manuscript has been submitted.
• We have successfully developed nanocomposites using agricultural waste and waste plastic derived graphene. The synthesized materials have been characterized by Raman, XRD, FTIR, UV, and TGA. Some characterization and lead removal studies are in progress.
• Also in this frame of time, we developed the material for graphene-based water filters. The synthesis of the material has been completed and the testing of the water filter made from our sample is in progress.

• In this study, the fate of three PhACs – atenolol (ATL), carbamazepine (CBZ), and diclofenac (DCF) were investigated in each component of the CW.
• The hydroponics study with Canna indica  removed 19.3 to 31.2% without substrate materials (initial PhACs:100 µg/L each). 
•  The breakthrough and sorption capacity of unplanted CW followed the order: natural zeolite (1.6-2.15µg/g) < Light-weight expanded clay aggregate (LECA) (5.37-8.27µg/g) < waste autoclaved aerated concrete (AAC) block (9.27-10.79µg/g) < wood charcoal (24.1-26.4µg/g), according to their surface and textural properties.
• Eventually, four laboratory-scale CW units with enriched microbes, C. indica , and different supporting materials were monitored for the removal of organics, nutrients, and PhACs. 
•  The synergistic interaction among AAC blocks, macrophytes, and microbial population in the system exhibited higher removal of COD, TN, TP, and PhACs as 88.6%, 81.6%, 77.6%, and 95.3%, respectively.
• Owing to the highly porous nature of waste AAC blocks, higher microbial activity was observed in the CW unit with AAC as substrate material.
• Performance of pilot scale ceramic membrane filter with pore size of 4 µm was tested for treating secondary treated wastewater under different operating conditions.
• Study showed that the filter was able to achieve desired treated wastewater quality with respect to pH, Turbidity, COD and Fecal coliforms.
• Removal efficiency of different pollutants such as turbidity, TSS, COD, and Fecal coliform ranged between 94-98.5%, 86-100%, 45-60%, and 80-85% respectively for 4µm pilot scale ceramic filter.
• Batch process was carried out to check the efficiency of filter by fixing the flow rate below 15m3/h till the pressure reaches 1.5 bar. For every cycle, the flux value has been calculated by using volume of water filled in the permeate tank w.r.t time and the Transmembrane pressure evolve during each cycle. Air + water Backwash was initiated at the end of each cycle. The provision of air + water backwash was able to recover the original flux during each cycle of operation.
• After modification work for continuous process, Flux Monitoring study has been carried out by fixing flowrate below 15m3/h for continuous process.
• Air + water Backwash was initiated for 30sec at the end of each cycle and the volume along with percentage of water used for backwash also estimated for every cycle. Optimization of running time by 20 minutes and 25 minutes was carried out for every cycle and flux also calculated.
• Chemical backwash was found to be effective in flux recovery Chemical washing was initiated to clear the blockage due to fouling when the transmembrane pressure not reduced as much after the air + water backwash. Chemical backwash was initiated in an efficient way by combining Caustic and hypochlorite and found to be effective. Overall cumulative net treated water and backwash water volume for 90 cycles was 2,53,718 L and 11,240 L, respectively. Percentage of water used for backwash was found to be below 5. Overall studies showed that the treated wastewater quality from ceramic filter (CF) was as same as the existing ultrafiltration (UF) outlet in IITM STP. The feasibility of decolorization of high concentration of azo dye Methyl Red (MR) in the presence of sucrose and NO3--N was evaluated in a laboratory scale membrane bioreactor operated in sequencing batch mode.
• Mixed microbial culture, which was previously enriched in a simple sequencing batch reactor under anoxic and static conditions, was used as seed biomass to decolorize high concentrations of MR (500 mg/L) using NO3--N as electron acceptor during start-up.
• After successful start-up, the reactor performance was assessed in increasing loading rates by decreasing the Hydraulic Retention Time (HRT) in different phases of reactor operation.
• Results indicate an effective decolorization of MR. Maximum removals of color (93%), COD (85%), and TN (81%) were achieved in phase I at a HRT of 16 d. On increasing the loading rate, the average removals obtained in phase III at a HRT of 4 d were color (77%), COD (78%), TOC (76%), and TN (95%). This process may help in treating dye effluents cost-effectively using hybrid technologies (biological treatment followed other advanced techniques) because around 75% of dye could be treated in anoxic conditions without external aeration.
• A review paper published based on nutrients recovery from wastewater to promote circular economy and sustainable agricultural practice in India·
• A book chapter (Springer) published titled ‘Hybrid Bioreactors for Dye Biodegradation’. A mini review paper published based on preliminary results of bio solids management using nano-scale oxides of Iron
• . Fine tuning AD-MEC unit and optimization of nitrogen flow rate as well as recirculation ratio (and flow rate)
• Estimation of energy harvesting and water quality purification potential of the MFC/MEC system along with accompanying efficient sludge utilization approach Inoculum development (SBR) – Development of bacterial consortia for the removal of carbon and nitrogen removal in Sequential batch reactor.
• Batch studies were performed to evaluate the efficiency of bacterial consortia.
• After acclimatization process, Sequential batch process was performed to study the efficiency of inoculum for the aerobic process (C & N removal) with the cycle time of 36 and 24 hrs was evaluated over a period of 240 days. Inoculum development (UASB) – Cultivation and enrichment of sulfur reducing bacteria (SRB) using three different medium
• The acclimatization of bacterial consortium for the removal of Sulphur and Nitrate and residual COD from the synthetic tannery wastewater. The initial concentration of COD in UASB was 830 (±165) mg/L which got reduced to 270 (±80) mg/L. The maximum removal efficiency of Sulphate was found to be 58.8 % with the initial concentration of 1028 (±86) mg/L and the sulphide concentration in the final effluent was 315 (± 58) mg/L.
• The performance of the SBR for three different COD of loading rates (1.36, 1.85, and 2.45) has been evaluated. SBR Kinetic studies has been performed to find the complete cycle and its treatment efficiency. Degradation kinetics were performed based on the experimental data obtained from SBR and found that Monod and first order model fits well.
• The performance of the SBR for four different nitrogen of loading rates (0.101, 0.145, 0.178, 0.237 g/L/d) has been evaluated over a period of 30 days at each loading rate and TKN removal efficiencies were found to be 83.3, 87.7, 83.3 and 80.9 respectively.
• Gene amplification was performed in the Bacterial sludge from SBR and confirmed the presence of ammonia oxidizing and nitrifying bacteria using PCR. Preliminary studies with Combined De-Sulfurization, De-nitrification and conversion of sulphide into elemental sulfur showed enhanced performance in the UASB with microaerophilic process.