Sunil Kumar Gupta

Size-segregated particulate matter and its association with respiratory deposition doses among outdoor exercisers in Dhanbad City, India

ABSTRACT Regular exercise improves physiological processes and yields positive health outcomes. However, it is relatively less known that particulate matter (PM) exposure during outdoor exercises may increase several respiratory health problems depending on PM levels. In this study, the respiratory deposition doses (RDDs) in head airway (HD), tracheobronchial (TB), and alveolar (AL) regions of various PM size fractions (<10, <2.5, and <1 μm; PM10, PM2.5, and PM1) were estimated in healthy male and female exercisers in urban outdoors and within house premises. The highest RDDs were found for PM during morning hours in winter compared with remaining periods. RDDs in AL region for males and females, respectively, were 34.7 × 10−2 and 28.8 × 10−2 µg min−1 for PM10, 65.7 × 10−2 and 56.9 × 10−2 µg min−1 for PM2.5, and 76.5 × 10−2 and 66.3 × 10−2 µg min−1 for PM1. The RDD values in AL region were significantly higher in PM1 (27%) compared with PM2.5 (13%) and PM10 (2%) during exercise in all periods. This result showed that the morning peak hours in winter are more harmful to urban outdoor exercisers compared with other periods. This study also showed that the AL region would have been the main affected zone through fine particle (PM1) to all the exercisers. Implications: Size-segregated particle concentrations in urban outdoors and within house premises were measured. The highest respiratory deposition doses (RDDs) were found for PM during morning hours in winter compared with remaining periods. During light exercise, the RDD values in alveolar (AL) region for PM10, PM2.5, and PM1 for male exercisers were significantly higher, 20.4%, 15.5%, and 15.4%, respectively, compared with female exercisers during morning peak hours in winter.

Management of Coalbed Methane and Coal Mine Produced Water for Beneficial Use in Damodar Basin of India

In India, coalbed methane (CBM) is rapidly emerging source of natural gas with current production levels of about 1.35 million metric standard cubic metres per day (mmscm/day) and expected to rise to 7 mmscm/day by 2020. CBM extraction associated with pumping of large amount of formation water to reduce hydrostatic pressure existing on gas-bearing coalbeds. At this time out of 32 awarded CBM blocks, only 6 blocks have commenced recovery of methane gas from about 200 wells, with water producing rate more than 20 m3 per well per day. Out of 424 underground coal mines, only 10–20 places, mine water is being used for domestic, washing of coal and other industrial uses with or without treatment. The high cost of water disposal and lack of efficient technology for treatment are barriers to advance development of CBM reserves in the country. If large amount of CBM and mine-produced water handled economically and treated efficiently to make it acceptable for different uses or surface discharge, it may become a source of fresh water. Produced water samples were collected from CBM production wells and different coal mines water disposal heads in various locations of Damodar basin and analysed using ICPMS and water analysis kit for the assessment of water quality. In CBM water the physical parameters like pH, electrical conductivity, TDS and alkalinity observed in the range of 7.23–8.72, 1678–5436 µs/cm, 1124.26–3642.26 mg/L and 1650–2150 mg/L respectively, whereas in coal mine water, it varies from 6.78 to 8.58, 623–1513 µs/cm, 417.41–1013.71 mg/L and 100–800 mg/L respectively. CBM water is mainly of Na–HCO3 type and coal mine water is Ca–Mg–SO4 and HCO3–Cl–SO4 type. Much of the produced water has total dissolve solids (TDS) content <3000 mg/L and can potentially be put to beneficial use within and outside the CBM industry. Sodium adsorption ratio (SAR) was calculated for each sample using concentration of sodium to the sum of the concentrations of calcium and magnesium. The higher the SAR, the greater the potential for reduced permeability, which reduces infiltration, reduces hydraulic conductivity, and causes surface crusting. Trace metal concentrations have a very similar range of distribution in both CBM and coal mine water. With minimal processing, much of this water may be used for a variety of industrial and agricultural purposes controlling pH, electrical conductivity, alkalinity, bicarbonate, sodium, fluoride, metals and SAR values. Drinking water availability is the major issue in Damodar basin; however the large quantity of water generated from CBM production wells can be potential freshwater sources for various applications, including potable consumption after RO treatment. This investigation employs CBM and mine water management strategies considering the spectrum of geologic, hydrologic and geochemical parameters to ensure environmental protection, foster beneficial use, treatment options of produced waters and improving reservoir performance. The CBM-produced water is derived from virgin multiple deep aquifer system having higher concentrations of Na+ and HCO3 −, while mine water is of shallow aquifer continuously flushed by seasonal rain water percolation and water drainage system employed in underground coal mine. It also reviews specific water treatment options and associated economics for managing CBM-produced water in Damodar basin.

Application of response surface methodology for optimization of an onsite electro-chlorinator for drinking water treatment

The potential of the novel electro-chlorination system assembled with graphite anodes for its application in drinking water supply was explored. The process parameter optimization was carried out using response surface methodology (RSM) approach and the optimal conditions for highest yield of active chlorine were arrived. The effect of the process variables were investigated using Box-Behnken design. The experimentally observed results were correlated and integrated to derive a mathematical model. The derived RSM model predicted active chlorine production was validated using various statistical parameters i.e., coefficient of determination (R2), adjusted R2 (R2adj), and predicted R2 (R2pred). The experimental results were fitted well with the quadratic model suggested by the software and the R2 value obtained was 0.9828. The study concluded that active chlorine formation can be optimized and modeled using RSM approach and can be effectively implemented.

Endeavor toward competitive electrochlorination by comparing the performance of easily affordable carbon electrodes with platinum

ABSTRACT Kinetics of chloride ion oxidation was studied on graphite, glassy carbon (GC), and platinum electrodes. The performance of the electrodes was monitored using the cumulative productivity and current efficiency of the cell as indicators. It was seen that the performance of the working electrode improved with repeated uses, the current efficiency increased from 22% in the third use to about 46% in the tenth use. The study also revealed that the role of diffusion to the total anodic current was insignificant and chloride ions were transported at the electrode surface only by conduction. The hypochlorite production in case of platinum was about 3.66 times than that of graphite and GC with the current efficiency of 75% in contrast to 46% found in graphite and GC. But platinum undergoes passivation to a significant extent unlike the graphite and GC electrodes. Chronopotentiometry experiments confirmed the passivation process in platinum electrodes, showed a steep rise in potential from 1.2 to 2 V while the electrode potential was uniformly maintained at 1.7 V in carbon electrodes. The highest io, exchange current density value was observed at 0.45 mA/cm2 in 0.5 M electrolyte, which is an indication of improved electrocatalytic activity with increased molar concentration. After continuous uses the corrosion rate studies revealed that platinum and GC electrodes were corrosion resistant whereas graphite underwent corrosion at the rate of 0.006 mm/h. The study dictated that carbon electrodes has great potential to be used as an alternatives to platinum electrodes, however, further investigations are required to assess its practical applicability in the public water supply system.