An introduction to heavy metal pollution and different technologies available for remediation

This paper revises the fundamental facts about potentially toxic elements belonging to the group of heavy metals. The study highlights the ongoing soil pollution status affected by these non-biodegradable elements, the basic characteristics of these metals that make them toxic, their mode of accumulation in different trophic levels, their toxic effect on human beings and the probable remediation technologies being used to remediate soils contaminated with heavy metal when the pollution problem has evolved. The technologies focused on solidification, soil washing, soil flushing, electro-kinetic remediation and phytoremediation are presented. The choice of the technology to be used for remediation depends on the condition of the soil and the extent of contamination. Conventional electro-kinetics is the most effective and rapid technology, but on the scale of ecosystem restoration, phytoremediation is an eco-friendly, green and cost-effective solution.

Duckweed: a model for phytoremediation technology

The Lemnaceae or duckweed family comprises 37 species of smallest and simplest flowering plants. Duckweeds have a fast growth rate, can survive under a wide range of temperature and pH conditions and are easy to maintain and harvest which makes them an excellent candidate for bioremediation of wastewaters. The main objective of the present review is to extend an appreciation for the potential of living and non-living biomass of duckweed in remediating waters contaminated with heavy metals. Along with showing the detailed mechanism of phytoremediation by duckweed, the paper also discusses the enhancement of duckweed phytoremediation by the integration of transgenic technology. Furthermore, the paper explores other applications of duckweed specifically as fuel, animal feed, in human nutrition, in medicine and as a life support system. Apart from this, various disposal mechanisms for harvested duckweed have been analysed. Current understanding of removal efficiencies of several contaminants by employing duckweed is limited mainly to laboratory experiments. More concentrated and persistent efforts to develop efficient approaches for the genetic transformation of duckweeds can expand the development and utilization of duckweeds.

Sewage sludge management at the central wastewater treatment plant Ljubljana

The treated sewage sludge under consideration is a hygienized biodegradable waste in the form of pellets. It can be used as a fertilizer, but only for spreading on non-agricultural land. Regarding “waste to energy” philosophy, the specification of pellets as an alternative solid fuel according to EN 15359 resulted in “NCV4; Cl1; Hg3-4” class. The major problem regarding the final pellets utilization is the lack of facilities for energy and material recovery from this type of waste in Slovenia. According to the newest legislation regarding the waste management, a product status for residues generated in combustion and pyrolysis of pellets on a laboratory and semi-pilot scale was not achieved. The holistic approach to final pellets utilization was studied and regarding the full-scale level of self-sufficient sewage sludge management in Slovenia, some legislative provisions become significant obstacles.

Physicochemical investigation of some primitive water sources in district Champawat for potability and preservation of historical aesthetics, Uttarakhand, India

The present study deals with the assessment of physicochemical properties of spring water samples collected from the surroundings of Champawat city, Uttarakhand, India. The total of twenty-three parameters were analysed for the study including pH, total dissolved solids (TDS) (mg/L), electrical conductance (EC) (µS/cm), temperature (T) (°C), dissolved oxygen (DO) (mg/L), chloride (Cl- ) (mg/L), and uranium (U) (µg/L). The seasonal variation was also observed in these samples. In the hills, spring water has been the common source of public water supply from ancient times, therefore this study includes the springs that have survived from the distant past and were being used for drinking purpose at earlier time. However, with time, the quality of these water sources has depleted due to both natural and anthropogenic reasons to such an extent that two of these sources are not in use any more. The analysis has shown that pH of these samples ranged from 6.74 - 7.77, the highest values of TDS and nitrate (NO3 - ) were observed to be 500 mg/L and 39.1 mg/L respectively. This study can help determine the present state of these ancient water sources, which can be used as alternative water sources in the time of water supply crisis, and maintaining these historical water sources can be an example of sustainable development and preservation of historical aesthetics.

Floristic diversity of Umari Dham sacred grove in Jaipur, Rajasthan, India

The Umari Dham is a sacred grove situated at the Jamwa Ramgarh Wildlife Sanctuary, Jaipur District of Rajasthan, India. It’s a beautiful arbour near the city of Jaipur. Umari Dham sacred grove has a temple, which has been visited by worshippers for approximately 450 years. During present field investigation, attempts were made to categorize the floral diversity of this sacred grove, and around 215 flowering plant species belonging to 159 genera under 52 families have been recorded according to Angiosperm Phylogeny Group III (APG III) classification. This grove serves as a vital pool for preservation of threatened, endemic and medicinal plant species.

Green manuring with crimson clover as an alternative to mineral fertilization in maize production

Role of mineral fertilizers is to complement the soils’ indigenous supply of minerals for crop plants nutrition. Among the mineral nutrients, nitrogen is generally considered as the most yield-contributing. Obtaining nitrogen from legumes is potentially more sustainable than from industrial sources. Crimson clover (Trifolium incarnatum L.) has long been appreciated as cover crop grown for green manuring due to its capability for binding the atmospheric nitrogen into plant-available form. Green manuring effects of crimson clover for succeeding maize crop were tested in 2019 year on two locations of Northeastern Croatia differing in soil texture: 1) on the site A where the soil was compact and dominated by clay and 2) on the site B where the soil was loose and dominated by loam. The research was conducted in a year with favourable rainfall during maize vegetation. Results have shown that green manuring with crimson clover for maize as the main crop delivered somewhat lower maize grain and aboveground mass yields than the conventional full-dose mineral fertilization on deep fertile soils around Osijek (Northeastern Croatia). When compared to conventional agronomy, green manuring was associated with additional agrotechnical operations required for crimson clover cover crop establishment and its herbage incorporation into soil prior to seeding main maize crop. Research should be continued in more different environments (year × location combinations) in order to produce reliable evaluation of crimson clover’s green manuring services.

Natural resources and policies for community-based ecotourism

This paper in particular deals with the analysis and reviews of the ecotourism policies and the framework of the state of Uttarakhand and the Indian government. In general, it evaluates and discusses the future and significance of the natural resources for the development of the community-based ecotourism in Uttarakhand for the sustainable development of the villages including conservation of biological diversity. This paper argues that the homestay programme, if encouraged, might help the state to achieve its goal of ecotourism and the green economy. Tourism was given an industry status by the government of Uttarakhand in 2018, providing attractive incentives and subsidies. Nevertheless, there is still a need for the appropriate policy framework for the better management of the natural resources, development and the training of the various stakeholders and the entrepreneurs involved in the community-based ecotourism industry.

Environment education in India

It is now widely acknowledged that the impact of human activities on environment is significant and will have serious consequences for future generations. Environment education has a significant role in making the youth conscious about their environment, adopting green social behaviour and thus responding to the environment crises. Recognizing the importance and need of environment education, India has initiated several efforts including making the environment education compulsory at all level of education. Today when environmental conditions are changing adversely and all living beings are suffering from the negative consequences of environmental pollution and climate changes, there is a need to reorient the curriculum of environment education for making it more attractive and responsive to the local environmental issues. Moreover, related policies are also needed to be restructured for sensitizing the people, especially school and college level students about the issues related to environment management.

From anthropocentrism to sustaincentrism: case study on beverage companies in India

Business organizations have been facing an unprecedented level of criticisms for being one of the prime contributors to the deterioration of environmental health. These criticisms have prompted organizations to make environmental sustainability a part of their business strategy. The case study on the beverage companies show how organizations are making a shift from anthropocentrism to sustaincentrism. Here we have mainly focussed on how PepsiCo and Coca-Cola have transformed their image from the one that contributes to bad health of the environment to the one that operates in an environment-friendly manner and how their environmental strategies have helped them in balancing the needs of stakeholders while earning profits.

Thermodynamic study of NOx and SO2 formation and possible reduction during Pb waste recycling

With the increasing demand for electricity due to the increasing economic boom, there is an excessive production of emissions that natural processes cannot cope with. Fortunately, there are various technological solutions for capturing harmful substances from produced emissions. However, the European Union aims to prevent the formation of emissions in the process of industrial production itself. In order to achieve this, it is necessary to reconcile the interests of individual European Union member states by the implementation of regulations into laws, to monitor short-term and long-term changes in air quality, and also to put into practice increasingly effective methods of capturing emissions from the air. This paper offers an example of thermodynamic calculation of quantities by appropriate software in the process of recycling waste from the metallurgical industry and possibilities of technological improvement in emission reduction.