Retraction Note to: Environmental impact of plantations in and around the petroleum refinery: a case study.

This article [1] has been retracted at the request of the Editor-in-Chief. Significant sections of the article show a similarity with the author's own article published previously [2]. All the authors agree with the retraction.

Particle size distribution in ambient air of Delhi and its statistical analysis.

Particle size distribution in ambient air has been studied in an urban city, Delhi. Different activity sites namely; kerbside, industrial and residential were selected for the study. The statistical analysis was carried out to study the frequency distribution and sources of different particle size fractions. The dominance of coarse particles attributed to local activities was observed at all the sites. It was observed that at kerbside sites, up to 52% of the particles were lower respiratory tract and up to 47% of the particles were upper respiratory tract particles. At residential and industrial sites, up to 40% and 31% were lower and upper respiratory tract particles, respectively. Factor analysis results indicated auto-exhaust as the dominant source of particulate matter at two of the kerbside sites. Resuspended dust was dominant at remaining two kerbside and residential sites. It was inferred using geometric standard deviation of particle size fractions that these were from different sources at residential and industrial site and from similar sources at three of the kerbside sites.

Environmental impact of plantations in and around the petroleum refinery: a case study.

Plantation or green belt (GB) grown around the factories and industrial premises improves the condition of land, mitigates air pollution (as the plants serve as a sink for pollutants and check the flow of dust, etc.), and reduces the level of noise pollution. The software developed by NEERI for the determination of the optimal width of GB in and around an industry is based on the pollution attenuation coefficient of selected plant species of deciduous trees existing in the region. The assessment of the impact of these plantations/green belts of 500-m width in and around a petroleum refinery in the west coast of India is evaluated for reducing/managing various waste generated, and it is observed that the overall efficiency is more than 60%.

Identification of air pollutant sampling period using horizontal dilution potential.

A new model is proposed for estimating horizontal dilution potential of an area using wind data. The mean wind speed and wind direction variation are used as a measure of linear and angular spread of pollutant in the atmosphere. The methodology is applied to monitored hourly wind data for each month of 1 year for wind data collected at Vadodara, Gujarat and monthly dilution potential is estimated. It is found that there is a gradual variation of horizontal dilution potential over a year with limited dilution during post monsoon period i.e., October and November and a high dilution in pre monsoon period i.e., May and June. This information can be used to design air quality sampling network and duration of sampling for source apportionment study. Air pollutant sampling during high dilution period can be carried out for identifying urban and rural dust and wind blown dust from mining activity. Air pollutant sampling during low dilution period can be carried out for capturing large amount of particulate matter from anthropogenic sources like elevated stack of furnace.

Source apportionment of PM10 in Mumbai, India using CMB model.

Source apportionment study is carried out to identify the sources of particulate matter of size less than 10 microm in Mumbai using chemical mass balance model. Various locations representing different activity zones as low activities (control), normal activity including commercial and residential areas and traffic sites (kerbside) are selected for this purpose to represent the city. It is observed that at control sites industrial contributions prevail, the other significant contributions are from marine and vehicular activities. At normal activity sites, vehicular, industrial and soil dust contributions are observed to be dominant. At two of the kerbside sites, marine contributions are observed to be significant which was due to the proximity of the sites to sea. The vehicular and soil dust contributions are observed to be significant at remaining kerbside sites. The study is useful for preparing the particulate matter reduction action plan for Mumbai, which can be extended further to other cities of India.

Microbial dynamics and enzyme activities during rapid composting of municipal solid waste - a compost maturity analysis perspective.

An investigation was carried out in the laboratory to find out the microbial dynamics and enzyme activities during rapid composting of municipal solid waste (MSW). Various treatments such as aeration (A), addition of chemical agents (glucose (G) and acetic acid (AA) and application of cellulolytic microbial (M) inoculum (Phanerochaete chrysosporium and Trichoderma reesei) were used to facilitate the decomposition of MSW. The result of the present investigation revealed that the degradation of organic substrates were quick (within 9-12 days) in case of rapid composting as indicated by the reduction (below 20) in C/N ratio. Whereas, normal composting took more than 20 days to attain C/N ratio of below 20. Estimation of selected enzymes (amylase, protease, phosphatase and cellulase) provided information on the substrate specific degradation profiles of various labile substrates contained in organic waste.

Qualitative evaluation of Kanhan river and its tributaries flowing over central Indian plateau.

Water quality evaluation of Kanhan river and its tributaries viz. Pench and Nag rivers was carried out in order to assess the qualitative changes and possibility of point and non-point pollution loads in these rivers for the post monsoon and summer seasons. pH, turbidity, conductivity, total alkalinity and total hardness were found in the range 7.18.7, 0.835 (NTU), 227970 (microScm(-1)), 7.18.7, 158486 (mg/L) and 142246 (mg/L), respectively. Ca, Mg, Na and K were in the range 2462, 1328, 15183 and 333 mg/L, respectively. The respective ranges of Cl, SO(4), NO(3) and PO(4) were observed between 19102, 823, 332 and 0.11.4 mg/L. DO and COD in the rivers ranged between nil to 8.5 and 7172 mg/L, respectively. Absence of DO and higher COD in Nag river is due to its sewage content from Nagpur city. Nag river showed higher bacterial counts than Kanhan and Pench rivers. The temporal and spatial variability in the river water quality may be attributed to catchment characteristics, agricultural and urban activities in catchment and on the bank of the river. The values of RSC, ESP and SAR indicated that the water of Kanhan and Pench rivers are suitable, whereas that of Nag river is unsuitable for irrigation purpose.

Measurement of particulate phase polycyclic aromatic hydrocarbon (PAHs) around a petroleum refinery.

A study on concentrations of ambient particulates viz. total suspended particulate matters (TSP), respirable suspended particulate matter (RSPM) and polycyclic aromatic hydrocarbons (PAH) were carried out at six sites around the Asia's largest, 12 MMTPA, petroleum refinery in west coast of India. PAH concentrations are correlated with each other in these sites, suggesting that they have related sources and sinks. The present article discusses the monitoring aspects such as sample collection, pretreatment and analytical methods and compares the monitored levels for assessing the source receptor distribution pattern. The main sources of RSPM and PAHs in urban air are automobile exhaust (CPCB, Polycyclic aromatic hydrocarbons (PAHs) in air and their effects on human health. " http://www.cpcb.nic.in/ph/ch21103.htm ", 2003; Manuel et al., Environmental Science and Technology, 13: 227-231, 2004) and industrial emissions like petroleum refinery (Vo-Dinh, Chemical analysis of polycyclic aromatic hydrocarbons, Wiley: New York, 1989; Wagrowaski and Hites, Environmental Science and Technology, 31: 279-282, 1997). Polycyclic aromatic hydrocarbons (PAH) are ubiquitous constituents of urban airborne particulate mostly generated by anthropogenic activities (Li et al., Environmental Science and Technology, 37:1958-2965, 2003; Thorsen et al., Environmental Science and Technology, 38: 2029-2037, 2004; Ohura et al., Environmental Science and Technology, 32: 450-455, 2004) and some of them are of major health concern mainly due to their well-known carcinogenic and mutagenic properties (Soclo et al., Marine Pollution Bulletin, 40: 387-396, 2000; Chen et al., Environment International, 28: 659-668, 2003; Larsen and Baker, Environmental Science and Technology, 32: 450-455, 2003). Limited information is available on PAHs contributions from refineries to ambient air. Hence this study would not only create a database but also provide necessary inputs towards dose-response relationship for fixing standards. Also, since it acts as precursor to green house gas, the data would be useful for climate change assessments. The objective of this article is to find out the concentration of PAHs in particulate matter around petroleum refinery and compare with their concentrations in major Indian urban centers.

Locating air quality monitoring station using wind impact area diagram.

In this study a new methodology is suggested to approximate the impact area downwind of an air pollution source, where air quality monitoring can be carried out to capture the maximum pollutant concentration. Hourly wind speed for a given month is grouped in to different wind speed ranges and the distance of pollutant travel is approximated from the average wind speed of that wind speed range. Since change in wind direction causes the impact distance to rotate, its rotation is approximated by the SD of wind direction change. Using this approach, area or region down wind of a source is determined and plotted. The pattern of monthly change of wind is better represented by the new type of diagram as compared to the wind rose diagram.

Hydrated cement: a promising adsorbent for the removal of fluoride from aqueous solution.

The present study was carried out to investigate the potential of cement hydrated at various time intervals for the removal of excess F- from aqueous solution by using batch adsorption studies. The influence of different adsorption parameters, viz. effect of adsorbent dose, initial concentration, pH, interfering ions and contact time were studied for their optimization. It was observed that the adsorbent exhibited reasonably significant F- removal over a wide range of pH. The presence of carbonate and bicarbonate ions in aqueous solution were found to affect the F- removal indicating that these anions compete with the sorption of F- on adsorbent. The equilibrium adsorption data were fitted well for both the Freundlich and Langmuir isotherms and the adsorption capacities were calculated. Comparative studies for F- removal in simulated and field water show relatively higher F- removal in simulated water. XRD and SEM patterns of the hydrated cement were recorded to get better insight into the mechanism of adsorption process. From the experimental results, it may be concluded that HC was an efficient and economical adsorbent for F- removal.

Monitoring and assessment of particulate matter and poly aromatic hydrocarbons (PAHs) around a petroleum refinery.

Ambient air particulates, both total and respirable fraction collected at number of locations around a petroleum refinery in west coast of India, having crude processing capacity of 12.5 million metric tones per annum, were analyzed and associated PAH concentrations were determined. PAHs in SPM near the refinery varied from 12% to 45% while in urban cities, it varied from 0.45% to 0.65%. The percentage PAHs in RSPM near the refinery varied from 6% to 20% while in urban cities, it varied from 0.5% to 1.45%. The refinery contribution of 11.5%-44.3% PAHs to ambient TSP and 5.5%-18.5% PAHs to ambient RSPM was observed. Non-respirable fraction of ambient TSP near refinery contributed upto 25% PAHs.

Anaerobic-aerobic treatment of purified terephthalic acid (PTA) effluent; a techno-economic alternative to two-stage aerobic process.

This paper addresses the treatment of purified terephthalic acid (PTA) effluent using anaerobic and aerobic processes. Laboratory studies were carried out on flow proportionate composite wastewater generated from the manufacturing of PTA. An activated sludge process (ASP-two stage and single stage) and an upflow anaerobic fixed film fixed bed reactor (AFFFBR) were used, individually and in combination. The performance of a full-scale ETP under existing operating conditions was also studied. Full scale ETP studies revealed that the treatment of PTA effluent using a two-stage ASP alone does not meet treated effluent quality within the prescribed Indian Standards. The biomass produced in the two stage ASP was very viscous and fluffy and the sludge volume index (SVI) was very high (200-450 ml/g). However, pretreatment of PTA effluent using an upflow AFFFBR ensured substantial reduction in BOD (63%) and COD (62%) with recovery of biogas at 1.8-1.96 l/l effluent treated at a volumetric loading rate (VLR) 4-5 kg COD/m(3) d. The methane content in the biogas varied between 55% and 60%. The pretreated effluent from the upflow AFFFBR was then treated through a single stage ASP. The biomass produced in the ASP after anaerobic treatment had very good settlability (SVI: 75-90 ml/g) as compared to the two stage ASP and the treated effluent quality with respect to BOD, COD and SS was within the prescribed Indian Standards. The alternative treatment process comprising an upflow AFFFBR and a single stage ASP ensured net power saving of 257 kW and in addition generated 442 kW of power through the AFFFBR.

Seasonal variation of toxic benzene emissions in petroleum refinery.

Petroleum refineries are largest chemical industries that are responsible for the emission of several pollutants into the atmosphere. Benzene is among the most important air pollutants that are emitted by petroleum refineries, since they are involved in almost every refinery process. Volatile organic compounds (VOCs) are a major group of air pollutants, which play a critical role in atmospheric chemistry. These contribute to toxic oxidants, which are harmful to ecosystem, human health and atmosphere. The variability of pollutants is an important factor in determining human exposure to these chemicals. The ambient air concentrations of benzene were measured in several sites around the Digboi petroleum refinery, near the city of Gowahati in northeast India, during winter and summer 2004. The seasonal and spatial variations of the ambient air concentrations of this benzene were investigated and analyzed. An estimation of the contribution of the refinery to the measured atmospheric levels of benzene was also performed. The ambient air mixing ratios of benzene in a large area outside the refinery was generally low, in ppbv range, much lower than the ambient air quality standards. This article presents the temporal and spatial variation of air pollution in and around petroleum refinery and showed that no health risk due to benzene is present in the areas adjacent to the refinery.

Use of wind data for estimating horizontal dilution potential of atmosphere.

In this study, a new methodology is suggested for estimating horizontal dilution potential of an area using wind data. The mean wind speed and wind direction variation are used as a measure of linear and angular spread of pollutants in the atmosphere. A formula is developed for estimating the potential of horizontal spread of pollutants in an area wherein only the wind speed and direction are used. The methodology is further applied to monitor wind data of one year. It is found that there is a very smooth variation of horizontal dilution potential over a year with limited dilution during post monsoon period and a high dilution in pre monsoon period.

Application of chemical, biological and membrane separation processes in textile industry with recourse to zero effluent discharge--a case study.

Environmental concerns associated with textile processing had placed the textile sector in a Southern State of India under serious threat of survival. The textile industries were closed under the orders of the Statutory Board for reason of inadequate compliance to environmental discharge norms of the State for the protection of the drinking water source of the State capital. In compliance with the direction of the Board for zero effluent discharge, advanced treatment process have been implemented for recovery of boiler feed quality water with recourse to effluent recycling/reuse. The paper describes to a case study on the adequacy assessment of the full scale effluent treatment plant comprising chemical, biological and filtration processes in a small scale textile industry. In addition, implementation of measures for discernable improvement in the performance of the existing units through effective operation & maintenance, and application of membrane separation processes leading to zero effluent discharge is also highlighted.