Riverbank stabilization based on the modulation of the near bank turbulence scales

Environment, Development and Sustainability - Sundarban area of the lower Gangetic plain experiences embankment failure almost every year due to the formation of toe undercuts. Waves generated due...     

Hydrogen Peroxide and Ultraviolet Irradiations in Water Treatment

Trihalomethanes (THMs) the by-products of chlorination in water treatment are recognised as a threat to public health due to their carcinogenicity. The photodegradation of THMs using hydrogen peroxide has been found to give increased removal efficiency and the outcome of the study may find, its application in designing a unit process for water treatment. Batch experiments were carried out using UV lamp of 83 W and 40% w/w Hydrogen peroxide (H₂O₂) in test waters between 2.5–10 pH range of chloroform, bromodichloromethane, dibromochloromethane and bromoform at 50–200 μg L⁻¹ initial concentration. 92–100% removal of chloroform, bromodichloromethane, dibromochloromethane and bromoform were found with 0.1% of H₂O₂ and 90 min of UV exposure.     

Biochemical changes in plant leaves as a biomarker of pollution due to anthropogenic activity

The air pollution due to anthropogenic activities seriously affected human life, vegetation, and heritage as well. The vegetation cover in and around the city mitigates the air pollution by acting as a sink for pollution. An attempt was made to evaluate biochemical changes occurred in four selected plant species, namely Azadirachta indica, Mangifera indica, Delonix regia, and Cassia fistula of residential, commercial, and industrial areas of Nagpur city in India. It was observed that the correlated values of air pollutants and plant leaves characteristics alter foliar biochemical features (i.e., chlorophyll and ascorbic acid content, pH and relative water content) of plants due to air pollution. The changes in air pollution tolerance index of plants was also estimated which revealed that these plants can be used as a biomarker of air pollution.     

Adsorptive Removal of Diuron Herbicide on Carbon Nanotubes Synthesized from Plastic Waste

In this study, carbon nanotubes (CNTs) were synthesized from waste polyethylene bottles and their use as an adsorbent for the removal of diuron herbicide from aqueous solution was evaluated. Batch adsorption was performed by varying adsorbent dosage, initial concentration, contact time, and temperature. Kinetic models applied to experimental data indicated that the pseudo-second-order model had the best fit. The equilibrium data were analyzed using different isotherm models. The adsorption capacity of CNTs for diuron removal, determined using the Hill isotherm, was approximately 40.37 mg/g at 303 K. From thermodynamic studies, the values of ΔH° (kJ/mol) and ΔS° [kJ/(mol K)] were calculated as ?17.307 and ?0.0528, respectively, which suggested that the adsorption process was exothermic. The negative values of ΔG° at three different temperatures indicated that adsorption of diuron on CNTs was favorable.     

Exploring risk,resistance and the power of myths among coastal fishing communities in Kerala,India

This paper attempts to capture the socially constructed nature of risk by analyzing the discourses embedded in community beliefs, myths and experiential narratives regarding coastal hazards and fishworkers' livelihoods. This paper draws insights from the works of James Scott on power and resistance in the everyday life of marginalized populations. Qualitative data for the study was collected using semi‐structured interview schedules, in‐depth group interviews, oral histories and storytelling across twenty marine fishing villages in Kerala. A significant finding of the study is that the communal discourse of coastal hazards or kolu is an integral part of fishworkers' resistance against formal authority and scientific knowledge systems in coastal management. The myths and beliefs of fishworkers are expressions of their concerns about present forms of development and coastal resource management.     

Community action planning in East Delhi: a participatory approach to build urban disaster resilience

The paper addresses disaster risk of an urban community in a mega city, which experiences high risk to natural hazards. The Community Action Planning (CAP) tool is used in this case. It has been developed from five resilience dimensions (physical, social, economic, institutional, and natural), 25 parameters and 75 actions. A detailed CAP structured questionnaire survey was conducted with 89 Residential and Welfare Associations (RWAs) in East Delhi, India situated in three types of settlements: planned Delhi Development Authority (DDA) housing and societies, colonies, and urban villages. The result identifies and prioritizes 32 actions as important for all three settlements. The result shows both consistent and inconsistent responses from RWAs. To give some examples, parameter S3 is “tasks to reduce number of people suffer from water borne diseases after a disaster”. In response to this parameter, approximately 80% of total respondents prioritized action (A1), “promoting people to take preventive measures after a disaster”. It shows consistent response from all three settlements. However, parameter S5 is “tasks to improve the awareness and knowledge about threat and impact of disasters”. Approximately 40% of total respondents prioritized A1, “organizing training program for awareness and knowledge building”. This action was prioritized in planned DDA housing and societies (56%) as well as in colonies (52%). However, none of the respondents from urban villages prioritized this action. These responses show inconsistency in response to specific action. In addition, the study shows the potential impact of CAP process for other communities in cities that are experiencing disaster risks and impact of climate change.     

Effect of heavy metals on earthworm activities during vermicomposting of municipal solid waste.

The effect of heavy metals on the activities of earthworm species Eudrillus eugineae was studied during vermicomposting of municipal solid waste (MSW) spiked with heavy metals. The activities of earthworms, in terms of growth and biomass production and number of cocoons produced, were monitored periodically, and the concentration of heavy metals in earthworms and substrates was determined at definite intervals. Laboratory-scale experiments were performed by mixing individual heavy metals in MSW. Copper, cadmium, chromium, lead, and zinc were selected for the study. The study concludes that heavy metals tend to accumulate in the body of earthworms; hence, the inherent concentration of heavy metals in the substrate before vermicomposting must be considered in view of composting of MSW and its application to soil. It was observed that copper and cadmium were toxic for the worms at 1.5 and 0.1 g/kg of the waste, respectively. The studies also suggest that earthworms are susceptible to the free form of heavy metals. Cadmium is the most toxic metal, followed by copper. Based on the investigation and observation, it was also found that earthworms should be separated from castings before the use of castings in soil amendments.     

Solid waste characteristics and their relationship to gas production in tropical landfill

Solid waste characteristics and landfill gas emission rate in tropical landfill was investigated in this study. The experiment was conducted at a pilot landfill cell in Thailand where fresh and two-year-old wastes in the cell were characterized at various depths of 1.5, 3, 4.5 and 6 m. Incoming solid wastes to the landfill were mainly composed of plastic and foam (24.05%). Other major components were food wastes (16.8%) and paper (13.3%). The determination of material components in disposed wastes has shown that the major identifiable components in the wastes were plastic and foam which are resistant to biodegradation. The density of solid waste increased along the depth of the landfill from 240 kg m⁻³ at the top to 1,260 kg m⁻³ at the bottom. Reduction of volatile solids content in waste samples along the depth of landfill suggests that biodegradation of solid waste has taken place to a greater extent at the bottom of the landfill. Gas production rates obtained from anaerobic batch experiment were in agreement with field measurements showing that the rates increased along the depth of the landfill cell. They were found in range between 0.05 and 0.89 l kg⁻¹ volatile solids day⁻¹. Average emission rate of methane through the final cover soil layer was estimated as 23.95 g⁻²day⁻¹ and 1.17 g⁻²day⁻¹ during the dry and rainy seasons, respectively.