Arunabha Majumder

Cadmium Removal by Lemna minor and Spirodela polyrhiza

The present study investigates the ability of two genus of duckweed (Lemna minor and Spirodela polyrhiza) to phytoremediate cadmium from aqueous solution. Duckweed was exposed to six different cadmium concentrations, such as, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 mg/L and the experiment was continued for 22 days. Water samples were collected periodically for estimation of residual cadmium content in aqueous solution. At the end of treatment period plant samples were collected and accumulated cadmium content was measured. Cadmium toxicity was observed through relative growth factor and changes in chlorophyll content. Experimental results showed that Lemna minor and Spirodela polyrhiza were capable of removing 42–78% and 52–75% cadmium from media depending upon initial cadmium concentrations. Cadmium was removed following pseudo second order kinetic model. Maximum cadmium accumulation in Lemna minor was 4734.56 mg/kg at 2 mg/L initial cadmium concentration and 7711.00 mg/kg in Spirodela polyrhiza at 3 mg/L initial cadmium concentration at the end of treatment period. Conversely in both cases maximum bio-concentration factor obtained at lowest initial cadmium concentrations, i.e., 0.5 mg/L, were 3295.61 and 4752.00 for Lemna minor and Spirodela polyrhiza respectively. The present study revealed that both Lemna minor and Spirodela polyrhiza was potential cadmium accumulator.

Arsenic Uptake by Lemna minor in Hydroponic System

Arsenic is hazardous and causes several ill effects on human beings. Phytoremediation is the use of aquatic plants for the removal of toxic pollutants from external media. In the present research work, the removal efficiency as well as the arsenic uptake capacity of duckweed Lemna minor has been studied. Arsenic concentration in water samples and plant biomass were determined by AAS. The relative growth factor of Lemna minor was determined. The duckweed had potential to remove as well as uptake arsenic from the aqueous medium. Maximum removal of more than 70% arsenic was achieved at initial concentration of 0.5 mg/l arsenic on 15th day of experimental period of 22 days. Removal percentage was found to decrease with the increase in initial concentration. From BCF value, Lemna minor was found to be a hyperaccumulator of arsenic at initial concentration of 0.5 mg/L, such that accumulation decreased with increase in initial arsenic concentration.

Removal of arsenic from drinking water using dual treatment process

This paper focuses on determining an efficient and simple method to remove arsenic from groundwater. Arsenic is a naturally occurring element widely distributed in the earth’s crust. Arsenic is very toxic when found in large quantities in drinking water. This report documents the selected treatment method and laboratory experimentation of arsenic removal from drinking water in small water delivery systems and domestic water systems. The objective is to expand upon research of new and existing arsenic removal technologies or promote a new, alternative process. Several treatment technologies have been considered to perform this function, but cost and reliability concerns prompted the decision to analyze small-scale, community-based filtration units, specifically. Based upon initial test data, the use of dual treatment method comprising of oxidation-coagulation-filtration and adsorption by activated alumina has proven to be more economic having more capacity and superior reliability as compared to other arsenic removal processes using various other media.

Quality of packaged drinking water in Kolkata City, India and risk to public health

AbstractIn recent years, packaged drinking water (PDW) has become one of the major sources of drinking water and is very popular among consumers. The study was conducted to assess the bacteriological and physicochemical quality of PDW sold in Kolkata city, India, and its effects on public health. The quality of Indian PDW has been compared with that of Kolkata Municipal Corporation (KMC) supply water. Further, the quality of PDW and KMC supply water has been compared with an average quality of bottled water of some branded companies of advanced countries with respect to relevant Indian and international standards (World Health Organization, IBWA, US FDA and EPA). The samples of 27 types of bottled PDW, 10 types of bubble top can PDW of different Indian brands and 18 samples of KMC supply water have been collected from different locations of the city. Physicochemical and bacteriological parameters of collected samples have been tested at School of Water Resources Engineering, Jadavpur University, as per AP...

Arsenic and Excess Fluoride Removal in Public Water Supply: Key Issues and Challenges

Water is essential for our life, livelihood, food security and sustainable development. It is a scarce natural resource but renewable through cyclic process of the climate. India having one-sixth of world population and 2.4% of world’s land area is to satisfy with only 4% of world’s renewable water resources. The per capita availability of water is decreasing in the country and it has reduced to one-third today compared to water availability during independence. The demand of water is increasing at a faster rate due to growing population, growing agriculture, food production, rapid industrialization and economic development. Again climate change in recent time has resulted in alteration of rainfall pattern. It has been predicted that the climate change is likely to increase the variability of water resources affecting livelihood and human health. Spatial rainfall pattern of varying characteristic has resulted in uneven water resources and thereby developing water stress and water-scarce situation in many stretches of the country. The situation has aggravated due to natural and anthropogenic pollution of both groundwater and surface water sources.

Urban Solid Waste Management: Key Issues and Challenges

Most of the cities and towns in India are plagued by the acute problems related to solid waste management (SWM). Municipal authorities provide conservancy services to the citizens and accordingly they are responsible for collection, transportation, treatment and disposal of solid waste. The solid waste management system needs improvement through introduction of source segregation of solid waste, door to door collection system, transfer station, improved transportation, composting of organic waste, energy recovery, value-based inorganic recycling, secured landfilling etc. Resource recovery through waste processing may partially solve the future land requirement problem of the municipalities. The SWM system should be established in a planned manner with provision of infrastructural facilities, funding and peoples’ participation. The municipalities should take up action plan to modernize SWM and ensure public participation.