Municipal solid waste management in Indian cities - A review

Municipal solid waste management (MSWM) is one of the major environmental problems of Indian cities. Improper management of municipal solid waste (MSW) causes hazards to inhabitants. Various studies reveal that about 90% of MSW is disposed of unscientifically in open dumps and landfills, creating problems to public health and the environment. In the present study, an attempt has been made to provide a comprehensive review of the characteristics, generation, collection and transportation, disposal and treatment technologies of MSW practiced in India. The study pertaining to MSWM for Indian cities has been carried out to evaluate the current status and identify the major problems. Various adopted treatment technologies for MSW are critically reviewed, along with their advantages and limitations. The study is concluded with a few fruitful suggestions, which may be beneficial to encourage the competent authorities/researchers to work towards further improvement of the present system.     

Simultaneous Removal of Nitrate and Natural Organic Matter from Drinking Water Using a Hybrid Heterotrophic/Autotrophic/Biological Activated Carbon Bioreactor

Simultaneous removal of nitrate ([Formula: see text]) and natural organic matter (NOM) from drinking water using a hybrid heterotrophic/autotrophic/BAC bioreactor (HHABB) was studied in continuous mode. The HHABB consisted of three compartments: ethanol heterotrophic part, sulfur autotrophic part, and biological activated carbon (BAC)-part (including anoxic and aerobic sections). Experiments were performed with [Formula: see text] concentration 30?mg N/L, [Formula: see text] loading rate 0.72?kg N/m(3)/d, C?:?N ratio 0.53, and three concentrations of NOM (0.6, 2.6, and 5.7?mg C/L). Overall denitrification rate and efficiency of the HHABB were not affected by NOM concentration and were in the suitable ranges of 0.69-0.70?kg N/m(3)/d and 96.0%-97.7%, respectively. NOM removal at concentration 0.6?mg C/L was not efficient because of organic carbon replacement as soluble microbial products. At higher NOM concentrations, total NOM removal efficiencies were 55%-65%, 55%-70%, and 55%-65% for dissolved organic carbon, trihalomethane formation potential, and UV absorbance at 254?nm (UV(254)), respectively. The more efficient compartments of the HHABB for the removal of NOM were the ethanol heterotrophic phase and aerobic BAC-phase. The efficiency of the HHABB in the removal of NOM was considerable, and the effluent dissolved organic carbon and trihalomethane formation potential concentrations were relatively low. This study indicated that the HHABB without the anoxic BAC-phase could be a feasible alternative for simultaneous removal of [Formula: see text] and NOM from drinking water at full scale.     

Synthesis of nanoparticles using microorganisms and their applications: a review

Environmental Chemistry Letters - Nanoparticles synthesis under green conditions has been performed using natural resources to diminish the use of toxic chemicals. For instance, microbial synthesis...     

Geo-based model of intrinsic resilience to climate change: an approach to nature-based solution

A substantial amount of researches have been done on the understanding and assessment of resilience from multiple perspectives, e.g., ecological, social, economic, and disaster management; however, recent international approach is trending toward more systematic and comprehensive risk assessment processes. Pivotal element of such approach is to emphasizing on promoting resilience in the face of climate change impacts. Conceptualization and identification of parameters to assess climate change resilience is one of the remaining challenges that academia is facing. Reviewing the principles of the climate change resilience highlighted in the literature, the goal of this study is to introduce a theoretical model about the climate change resilience concept to facilitate and enhance future climate change resilience-related researches. The model proposed in this study is named as the climate change resilience of place (C-CROP) model, a geo-based model which is designed to assess climate change resilience for any geographic region with an approach to the incorporation of nature-based solution (NBS). C-CROP model considers vulnerability, exposure, sensitivity to climate change on one side; another side is co-benefit, climate proofing, and disservices of proposed NBS. An operational framework of the C-CROP model is also proposed, that allows spatially explicit assessment of climate change resilience in real world by developing an indicator-based framework and comprehensive mapping using the geospatial approach. Therefore, this model includes vulnerability hotspots identification; better understanding of the pathways of resilience; and solutions (i.e., NBS) to infer the impacts and effectiveness of resilience-building interventions.

     

Quantification of polychlorinated biphenyl contamination using human placenta as biomarker from Punjab Province,Pakistan

Environmental Science and Pollution Research - The present study biomonitored the placental polychlorinated biphenyl (PCB) concentrations in women from Punjab Province, Pakistan, that provides the...     

Anaerobic bioconversion of carbon dioxide to biogas in an upflow anaerobic sludge blanket reactor

The increasing concentration of carbon dioxide (CO2)--the most dominant component of greenhouse gases--in the atmosphere has been of growing concern for many years. Many methods focus on CO2 capture and storage and there is always the risk of CO2 release to the environment. In this study, a new method to convert CO2 to biogas with a high content of methane (CH4) in an anaerobic system with a lab-scale upflow anaerobic sludge blanket reactor at 35 degrees C was developed. In a series of experiments, the reactor was run with and without CO2-saturated solutions including volatile fatty acids (VFAs) as sources of hydrogen. The concentration of dissolved CO2 in the influent solutions was 2.2-6.1 g/L, with corresponding chemical oxygen demand (COD) values of 2.6-8.4 g/L for the solutions. Overall CO2 removal values of 2.7-20 g/day (49-88% conversion) were obtained for the organic loading rates (OLR) and CO2 loading rates of 8-36 gCOD/L day and 6-26 gCO2/L x day, respectively with CH4 purity of above 70%. Also, VFA and COD removal were in the range of 79-95% and 75-90%, respectively. Methanogenic activities of the cultures with the concentrations measured as volatile suspended solids (VSSs) were 0.12-0.40 L CH4/gVSS x d with the highest value for the system containing acetic acid. This anaerobic method can be applied to reduce CO2 emitted to the atmosphere from a wide variety of industrial point sources with a value-added product, CH4.     

Habitat preference and population estimates of Indian pangolin (Manis crassicaudata) in district Chakwal of Potohar Plateau,Pakistan

Indian pangolin (Manis crassicaudata) is a fossorial, “Near threatened” mammalian species occurring in Pakistan and facing a risk of endangerment in its wild habitat. Being nocturnal, ecological data of the species is lacking in the country and in south Asia as well. The current study investigated some ecological parameters of the species like, distribution, habitat analysis, population and food habits in district Chakwal of Potohar Plateau. Illegal trapping and killing by professional nomads for its scales is the main threat to the species in the study area.     

Effect of land use activities on PAH contamination in urban soils of Rawalpindi and Islamabad, Pakistan

Urbanization can increase the vulnerability of soils to various types of contamination. Increased contamination of urban soils with polycyclic aromatic hydrocarbon (PAH) could relate to increased number of petrol pump stations and mechanical workshops—a phenomenon that needs to be constantly monitored. This study was undertaken to explore the soil PAH levels in Rawalpindi and Islamabad urban areas in relation to land use activities. Composite soil samples from petrol pump stations and mechanical workshops (n?=?32) areas were evaluated for five PAHs––naphthalene, phenanthrene, pyrene, benzo[a]pyrene, and indeno(1,2,3-cd)pyrene—and compared with control area locations with minimum petroleum-related activity (n?=?16). Surface samples up to 3 cm depth were collected and extraction of analytes was carried out using n-hexane and dichloromethane. Prior to running the samples, standards (100 μg ml^–1) were run on HPLC to optimize signal to noise ratio using acetonitrile as mobile phase at a flow rate of 1.25 ml/min at 40 °C. Significant differences between petrol pump stations and mechanical workshop areas were observed for individual PAH as well as with control area soil samples. Naphthalene was found to be the most abundant PAH in soil, ranging from 2.47 to 24.36 mg kg^–1. Correlation between the benzo[a]pyrene (BaP) level in soil and the total PAH concentration (r?=?0.82, P?<?0.0001) revealed that BaP can be used as a potential marker for PAH pollution. A clear segregation between petrogenic and pyrogenic sources of contamination was observed when low molecular weight PAHs detected in soil was plotted against high molecular weight PAHs. The former source comprised lubricants and used engine oil found at mechanical workshops, whereas the latter could be mostly attributed to vehicular emission at petrol pumps. The results indicate that PAH contamination in urban areas of Rawalpindi and Islamabad has direct relevance with land use for petroleum activity. We conclude that in order to reduce the soil PAH exposure in urban environment, petrol pumps and mechanical workshops must be shifted to less densely populated areas because of their role as important point sources for PAH emission.     

Health risk assessment of occupational exposure to styrene in Neyshabur electronic industries

Environmental Science and Pollution Research - Styrene is one of the essential components in making thousands of everyday products. Occupational exposure to styrene causes pulmonary, neurological,...