|Qualification:||Ph.D(Organic Chemistry),M.Sc(Organic Chemistry),Alexander von Humboldt Fellow|
Environmental Chemistry/Water Quality Assessment
CSIR-NEERI, Nehru Marg, Nagpur
|Sr. No.||Publication Name|
3D printing of high surface area ceramic honeycombs substrates and comparative evaluation for treatment of sewage in Phytorid application
Substrates properties play an important role in immobilization of bio-organisms and hence in optimizing design of the bioreactor to maximize the performance. Highly flexible 3D printing process based on virtual Computer Aided Design (CAD) is used for producing honeycomb substrates with desired properties. Clay based honeycomb with square, triangular and hexagonal configurations are 3D printed in order to achieve substrates with pre-designed geometrical surface areas. Laboratory reactors were fabricated with engineered properties using 3D printed honeycombs and a combination of honeycombs and commonly used stones for performance evaluation. Additionally, reactor based on commonly used gravel stones also fabricated for sake of comparison of performance. In order to elucidate the performance, sewage mix was fed into the reactors and the space velocity of all the three reactors were maintained at 0.041 h?1. The sewage before and after treatment was tested for the performance markers such as pH, TSS, BOD and COD. Treated water met the stipulated standards prescribed by American Public Health Association with respect to all parameters studied. Though the difference in the performance of the reactors was marginal, with honeycombs a substantial reduction in the weight of the reactor can be accrued along with high mass transfer due to low pressure drop which can be attributed to the inherent higher surface to volume ratio. Further, by engineering the surface porosity of the honeycombs, it is possible reduce TSS as demonstrated in this study. These advantages offer flexibility in scaling up the reactors for larger capacities for de-centralized requirements.
Hydrodynamic and Advection-Dispersion Simulation of Cool Seawater Discharges from an LNG Facility
The impact of cool seawater discharge in the coastal waters from a Liquefied Natural Gas (LNG) plant has been simulated using MIKE21. In this work, hydrodynamics conditions of the coastal waters were calibrated and corroborated to predict the cool seawater discharge under two plant design scenarios by selecting flow rate 15 m3 /s and 10 m3 /s with a temperature drop of 5 °C and 7 °C, respectively. The simulations were carried out under different scenarios, to arrive at the best possible case to minimize the potential impact on the coastal environment. Both the simulated scenarios complied with the available World Bank guidelines for LNG facilities. However, the designed scenario of flow rate 10 m3 /s with a temperature drop of 7 °C between inlet and outlet presents a better choice as it reduces the pumping power of seawater intake. As there are no Indian guidelines for cool seawater discharges from LNG plant, the present work can support the policymakers and regulators to formulate coherent discharge standards.
Traffic noise prediction model of an Indian Road: An increased scenario of vehicles and honking
Noise is considered as an underrated and underemphasized pollutant in contrast to other pollutants of the environment. Due to the non-acute response of health effects, people are not vigilant towards consequences regarding noise pollution. The expansion of the transportation industry is contributing towards the increment in the public and private vehicular volume which causes an increment in noise pollution. For evaluation of respective scenario, the research study has been conducted on one of the minor roads of Nagpur, India; for 2 years, viz., 2012 and 2019. The study concludes an increment of 5–6 dB(A) in noise level, 4–6 times in honking, and 1.7 times in traffic volume. The study confirms increment in sound pressure by 65.9% and 81.9% for the year 2012 and 2019 during morning and evening sessions, respectively. Noise prediction model has also been developed for the abovementioned years, using multiple regression analysis, considering traffic volume, honking, and speed against noise equivalent level. Honking has been further characterized into honk by light and medium category vehicles as acoustical properties of horns vary with respect to category of vehicle and introduced into the noise prediction model. Noise prediction model for 2019 has predicted the noise level in a range of ? 1.7 to + 1.4 dB (Leq) with 84% of observations in the range of ? 1 to + 1 dB (Leq), when compared with observed Leq on the field. For proper management of noise pollution, a noise prediction model is essentially needed so that the noise level can be anticipated, and accordingly, measures can be outlined and executed. This increased noise level has serious impacts on human hearing capacity and overall health. Accordingly, noise mitigation preventive measures are recommended to control traffic noise in the urban environment.
Environmental Science and Remote Sensing Applications in Hydrological Studies
Geospatial assessment of land surface temperature in Nagpur, India: an impact of urbanization
Temperature is one of the factors which affects the meteorological phenomenon prevailing in an urban area and ultimately leads to climate change and global warming. Measurement of surface temperature with conventional temperature sensors is tedious, has single point value and expensive. Satellite data of 2005, 2008, 2010 and 2016 are used to assess the land use land cover (LULC) and to measure the land surface temperature (LST) during the hottest month of May in Nagpur city, India. Based on the image analysis, it is observed that there is an increase in the average temperature from 40.0 to 44.6 ºC. This may be due to an increase in built-up area from 55.5 to 69.8% during 2005 to 2016, respectively. It has also been revealed that the outskirts of the city are hotter than the central portion of the city as there is more barren land on the outskirts. Results were compared to ambient temperature sensor that showed good agreement between temperature retrieved from satellite and temperature sensor. The study suggests that urban areas should be developed intermixed with vegetation and plantation and provisions of green belt along the city roads, highways and ring roads. Based on LST and LULC analysis, a green belt of 30 m along both sides of the road would lower the road temperature by 9.3 ºC from existing temperature of 44.7 ºC. This would help in lowering down the average temperature of the city.
Characterization of Honking Noise in Urban Environment of Nagpur
India where festivals and functions are incomplete without blare sound of loudspeakers in every nook and corner introduces noise as a pollutant in the environment. Contributing to such activities, major sources of noise seeks to be the traffic noise which also entails noise produced by constant honking scenario of the vehicles. Due to existing heterogeneous condition of traffic scenario in India, the research was carried out on National highway whichemphasis on characterization of traffic and honking noise. Traffic volume, noise metrics with statistical indicators (Leq, L10, L90, Lmax, Lmin) were observed during morning, afternoon and evening session. Study includes manual quantification of honking incident of different categories of vehicle (light and medium), which exhibit positive relationship with observed Leq level. As per traffic volume data collected, 60-64% light category vehicles contributed 60-70% honks and medium category vehicle volume of 29- 32% contributing 30-40% of honks. Statistical analysis and
Geospatial assessment of urban sprawl and landslide susceptibility around the Nainital lake, Uttarakhand, India
Landslide is one of the challenges faced by mountainous regions due to natural phenomena and human activity. Nainital district in the state of Uttarakhand is one of the popular tourist spots in India. It is situated in a lesser Himalayan belt facing experiences number of landslides every year. This region comes under the Main Boundary Thrust and Main Central Thrust which are considered to be very sensitive for landslides. Landslide susceptibility mapping is a proficient tool to identify vulnerable zones for landslides. Remote sensing and geographic information system are very effective tools for collecting, analysing and interpreting land use data, and on the other hand, multi-criteria valuation (MCE) allows users for decision-making by considering various factors affecting the process of the landslide. The MCE technique was applied considering present land use/land cover, slope, drainage, lithology, geomorphology, and type of soil. Overlay analysis and land susceptibility mapping was carried out for the area around the Nainital lake. The study concludes with hot spot analysis and recommends mitigation measures like geotextiles, retaining walls and strict building by-laws for preventing landslides.
Impact of urbanization on creeks of Mumbai, India: a geospatial assessment approach
Creeks are the inherent coastline feature that connects rivers to the sea and plays an important role in the ecological processes and the material transfer. In the present study, an impact of urbanisation on the creeks of Mumbai, India namely Thane, Malad and Manori creeks, has been addressed. Multi-temporal satellite images of Landsat for the years 1972, 1994 and 2016 are considered to perform the changes in the mudflat and growth of the mangrove, as well as the changes in creeks width apart from the Land use Land cover (LULC). Object-based image analysis using multi-spectral resolution confirmed that there is an overall increase in the spatial extent of mangroves and reduction in the width of all the creeks. Mangroves around Thane creek and Manori creek have increased from 50.7 km2 to 57.6 km2 and 8.4 km2 to 25.2 km2respectively. However, there is a decrease in mangroves around Malad Creek from13.3 km2 to 9.7 km2during 1972 to 2016. The relationship between the creek geometry and LULC was also explored, and it has been revealed that the creek width has reduced due to urbanisation. Life expectancy analysis projected a further reduction in the width of the creeks for the years 2025 and 2050. The study suggests that there must be stringent bye-laws for disposal of sewage into the creeks and development activity near the creek areas. Further, upper stretches of the creeks require cleaning and dredging so that the tidal water will be approached up to the upper portion to maintain the creek ecosystem.
An impact of sewage pumping failure on coastal water quality of Mumbai, India
A model was conceptualized to emulate the behaviour of coastal water during high and low tides and the impact of the pump failure in present and projected future scenarios was estimated on it. The model was validated before being used for failure scenario simulation. The study indicates that potential adverse effects on water quality are imminent in case of sewage pumping station failure and warrants better planning and management in terms of diversionary and evacuation routes and preparedness plans.
Noise pollution in Mumbai Metropolitan Region (MMR): An emerging environmental threat
Noise pollution in urban areas is an emerging environmental threat which local agencies and state authorities must consider in planning and development. Excessive noise is becoming a significant problem adversely affecting the physiological and psychological health of the citizens. Present study was carried out to assess and quantitatively evaluate ambient noise levels in Mumbai Metropolitan Region (MMR) consisting of 9 cities namely Bhiwandi-Nizampur, Kalyan-Dombivli, Mira-Bhayandar, Mumbai, Navi Mumbai, Panvel, Thane, Ulhasnagar and Vasai-Virar. The noise environment was assessed on the basis of equivalent continuous sound pressure levels (Leq), day-night noise levels (LDN) and noise limit exceedance factor (NEF) during day and night time of working and non-working days in four different area categories, viz. industrial, commercial, residential and silence zones. Present study shows that silence zones have been the worst affected areas where noise pollution levels and NEF indicate excessive violation of permissible noise limits due to unplanned, congested and unruly spaces for developmental and commercial activities, followed closely by residential and commercial zones. Cities with separate industrial and commercial zones showed less noisy surroundings in comparison with those cities where land use pattern of industrial and commercial zones is around or overlapping each other. It can thus be concluded that appropriate demarcation and planned use of city space is important to avoid exposure to rising noise pollution levels. Based on the noise pollution in (MMR), various control measures are suggested including awareness campaign and strict compliance of the rules and regulations.
An innovative approach of urban noise monitoring using cycle in Nagpur, India
Noise is one of the most significant sources of environmental pollution in metro cities. Traffic noise plays an important role to contribute to ambient noise pollution. Noise pollution monitoring was carried out using sound level meter mounted on the cycle with the help of mould fixed on it. Cycle is a noiseless mode of transport and therefore, it was used for noise monitoring over 700 locations in Nagpur City. Noise levels were recorded at each location for 5 min during peak rush hours of traffic in the morning and in the evening at an interval of 1 s leading to around 300 readings each. Noise indices like Leq, L90, L10, Lmax and Lmin were calculated for noise level data analysis. TNI was also determined for analysis of traffic noise on intersections of roads. Equivalent noise levels were transferred into the Geographic Information System (GIS) and spatial analysis tool was used to create spatial and strategic noise maps. Based on the maps, it is revealed that noise levels are exceeded all over the city with respect to ambient noise standards. It was experienced that intersections of roads during peak rush time are very noisy due to honking. The study recommends the noise monitoring through cycle-mounted sound level meter since it covers unapproachable sites, more coverage in the city that helps in identifying hotspot area of concern for noise abatement strategies and planning.
Hydrodynamics and water quality simulation of Thane creek, Mumbai: an impact of sewage discharge
To assess the impact of sewage discharges on creek water quality, a hydrodynamic and water quality simulation was carried out for Thane Creek. DO and BOD values showed non-compliance up to middle and upper stretches during low tide and even in upper stretch during high tide. FC was found beyond compliance level during low and high tides. Simulated results were correlated with observed tide and current as hydrodynamics and DO, BOD and FC as water quality parameters with correlation coefficients 0.66 to 0.91.
Impact of Sewage Discharges on Coastal Water Quality Mumbai, India: Present and Future Scenarios.
The simulation study assesses the impact of sewage discharges on the present and predicted water quality of the Mumbai coast using MIKE 21. Water quality parameters in terms of dissolved oxygen (DO), biochemical oxygen demand (BOD) and faecal coliform (FC) are checked against specified standards. The simulation is validated for the present coastal hydrodynamics and observed water quality parameters. The validated model is further used for predicting scenarios in terms of upgradation in a pumping station and improvement in wastewater collection, treatment level and disposal systems. The water quality of the existing coastal environment does not conform to the stipulated standards but improves considerably in the prediction scenarios. However, despite a marked improvement in FC, it is not as per desired standards as no treatment for bacteria removal is considered. The simulation study emphasizes the need for exploring options like the reuse or recycle of treated effluent, as an effort for water conservation.