Ecological restoration of coal fly ash–dumped area through bamboo plantation.

The present study entails the phytoremediation potential of different bamboo species on 5-year-old FA-dumped site near Koradi thermal power plant of Nagpur, Maharashtra, India. The selected FA-dumped site was treated with farmyard manure, press mud, and bio fertilizer followed by plantation of six promising species of bamboo namely Bambusa balcooa Roxb., Dendrocalamus stocksii (Munro.) M. Kumar, Remesh and Unnikrishnan, Bambusa bambos (L.) Voss, Bambusa wamin E.G. Camus, Bambusa vulgaris var. striata (Lodd. ex Lindl.) Gamble, and Bambusa vulgaris var. vittata Riviere and Riviere. The experimental results indicated that the organic input in the FA-dumped site nourished the soil by improving its physico-chemical, and biological characteristics. The results revealed the contamination of the site with different trace elements in varied quantity including Cr (89.29 mg kg−1), Zn (84.77 mg kg−1), Ni (28.84 mg kg−1), Cu (22.91 mg kg−1), Li (19.65 mg kg−1), Pb (13.47 mg kg−1), and Cd (2.35 mg kg−1). A drastic reduction in concentration of heavy metals in FA was observed after 1 year of bamboo plantation as compared to the initial condition. The results showed that bamboo species are good excluders of Ba, Co, Cr, Li, Ni, Mn, and Zn, whereas they are good accumulators of Cd, Pb, and Cu. The values of biochemical parameters, such as pH, total chlorophyll, ascorbic acid (AA), and relative water content of all the bamboo leaves ranged from 5.11–5.70, 1.56-6.33 mg g−1, 0.16-0.19 mg g−1, and 60.23–76.68%, respectively. It is thereby concluded that the bamboo plantation with biofertilizers and organic amendments may indicate adaptive response to environmental pollution on FA-dumped site

Stabilized landfill leachate treatment by zero valent aluminium-acid system combined with hydrogen peroxide and persulfate based advanced oxidation process

The toxic leachate generated from landfills is becoming a major nuisance to the environment and has vital role in groundwater contamination. This study evaluated the potential of zero valent aluminium (ZVAl) based advanced oxidation processes (AOPs) for stabilized landfill leachate treatment. Hydrogen peroxide (HP) and persulfate (PS) were used to generate additional radicals in aerated ZVAl acid process. ZVAl-acid system achieved 83% COD removal efficiency under optimized conditions such as acid washing time of 20 min, ZVAl dose of 10 g L�1 at initial pH 1.5. The highest exclusion efficiencies in terms of TOC, COD as well as color were 83.52%, 96% and 63.71% respectively in treatment systems showing the following order: ZVAl/H+ /Air/HP/PS > ZVAl/H+ /Air/PS > ZVAl/H+ /Air/HP > ZVAl/H+ /Air > ZVAl/H+ . The involvement of other metals such as Fe and Cu in the process has been found. The reusability study revealed that ZVAl powder can be effectively used up to three cycles. The 28.48 mg/l of Al3+ residue was observed in this process which has to be removed before discharge of effluent. The study indicated that the ZVAl based AOPs is stable and active for the degradation of organic pollutants present in landfill leachate and a promising solution except for the aluminium discharge which has to be given special care

Evaluation of Hydrochemical Facies and Suitability of Water in Tilaiya Dam Reservoir of the Jharkhand State in India

The reservoir at Tilaiya Dam in the Jharkhand state of India is one of the most important freshwater sources in the region. The water of the reservoir is primarily used for domestic, drinking, and irrigation. Water quality of the reservoir was monitored at five locations during pre-monsoon, monsoon, and post-monsoon seasons in 2017-2018 to understand spatiotemporal variation and also, the suitability of water for existing uses. A hydro-geochemical analysis of reservoir water was undertaken with the help of Piper Diagram, Schoeller-Berkaloff diagram, Stiff diagram, U.S Salinity Laboratory diagram, Water Quality Index, Salinity Index, Sodium Percentage, Sodium Absorption Ratio, Magnesium Hazard, etc. The hydrochemical facies in the present study showed that water was of Ca-HCO3 water type. Factor analysis revealed two predominating factors, both geogenic in nature, that influenced reservoir water quality, accounting for 81.992 % of the variance in data. Slight variation in water quality was observed with time and space but it was nonsignificant statistically. Water Quality Index had increasing trends at three sites from monsoon to pre-monsoon through post-monsoon and winter seasons. The study revealed that the water of the reservoir is good and suitable for drinking, domestic use, irrigation, and industry in all the seasons during 2017-18

Continuous treatability of oily wastewater from locomotive wash facilities by electrocoagulation

The present work focuses on the feasibility of electrocoagulation (EC) process for the treatment of oil and grease wastewater generated from locomotive wash facilities. Experimental investigations have shown the influence of various factors affecting EC using continuous reactor. The effect of various operating parameters, like reaction time, electrode spacing, and applied voltage, was investigated and optimized using Box-Behnken design method. The optimized value of applied voltage and electrode spacing were found to be 28 V and 3 cm, and Chemical Oxygen Demand removal efficiency obtained was 91.9%. As a result, EC process can be an alternative method for the treatment of oily wastewater

Treatment of mixed industrial wastewater by electrocoagulation and indirect electrochemical oxidation

Treatment of mixed industrial wastewater is a challenging task due to its high complexity. This work scrutinizes the electrochemical treatment of mixed industrial wastewater, specifically electrocoagulation and indirect electrochemical oxidation processes through COD and color removal studies. Both processes are found to be more efficient at the wastewater pH. Monopolar connection was found more effective than bipolar connection for the removal of COD and color from wastewater. The monopolar connection removed COD up to 55% and color 56% whereas bipolar connection leads to the removal of 43% and 48% respectively at wastewater pH with an applied voltage 1.5 V in the course of 1 h of electrolysis. In the case of indirect electrochemical oxidation process using graphite electrodes, the COD and color abatement efficiencies of the indirect electrochemical oxidation process were found as 55% and 99.8%, respectively within 1 h of electrolysis conducted at pH 7.7, applied voltage 4 V, and NaCl concentration 1gL1 . This work also highlights the importance of the presence of electrolytes in the indirect electrochemical oxidation process as the external addition of sodium chloride significantly enhanced both COD and color elimination efficienc

Eco-rejuvenation of degraded land by microbe assisted bamboo plantation

Eco-restoration is a technique for rejuvenation of degraded ecosystem to their near original state. It also helps to control soil erosion, develop microbial ecology, enhance biomass production and socio-economic development. The present study was focused on a new approach called Eco-Rejuvenation Technology (ERT) for reclamation and ecological/biodiversity restoration of degraded land. To demonstrate this technology, plantation of seedlings of 5 different bamboo species (Bambusa balcooa Roxb., Bambusa vulgaris var. vittata (Schrad. ex Wendl) (Green), Bambusa vulgaris var. striata (Yellow), Bambusa nutans Wall. ex Munro and Dendrocalamus asper (Schult.f.) Backer ex Heyne) was carried out in a village community degraded land located in Central India where organic amendments, such as press mud, farmyard manure and bio-fertilizers were apllied. This study showed how ERT benefited the growth of bamboo (viz., increased height, diameter, number of culms) and further explained how it could help in increasing soil biomass and carbon sequestration capacity over a period of one year. The results reflected that the success of a rural wasteland restoration program depends on community participation and socio-economic factors as well as ecological improvement. In this study, the soil organic carbon (SOC) was restored to nearly 1% within a year. It clearly suggested that ERT is a potential tool for sustainable rural development through native biodiversity development on degraded land

Importance of Graphene in the Electro-Fenton Process

Graphene-based nanomaterials have attracted researchers from various fields due to their extraordinary physical, chemical, and electrochemical properties. An emerging class of graphene-based nanostructures and nanocomposites is considered to be a promising solution to various types of environmental pollution. The electro-Fenton process is one of the easy and effective approaches to treating a wide range of organic pollutants in a liquid medium. The usage of graphene-based electrodes in the electro-Fenton process is considered to be a promising and cleaner way to produce reactive oxygen species to mineralize organic contaminants rapidly. Graphene derivatives are used to immobilize various heterogeneous Fenton catalysts for improved catalytic activity, stability, and reusability. In this review, the importance of graphene-based materials in improving the performance efficiency in the electro-Fenton process is presented along with an enhancement mechanism through the following discussions: (i) the significance of oxygen functional groups and nitrogen doping on graphene layers to enhance the two-electron oxygen reduction reactions; (ii) the advantages of iron-loaded graphene-based materials as catalysts and composite electrodes for the enhanced production of reactive oxygen species; (iii) a summary of various forms of graphene-based materials, modifications in their chemical structure, properties, and applications in the electro-Fenton process to remove organic contaminants

An Integrated Process of Value Addition to Citrus Waste and Performance of Fenton Process for Its Conversion to Biogas

Citrus fruits are commercially important fruit crop all over the world. About 50–60% of citrus fruit is considered waste including peels and its handling is costly at municipal and industry levels. Citrus wastes in general show a low pH (3–4), relatively high water content and organic matter. Its composting is not recommended, as it has inherent low pH and presence of high concentration of limonene in essential oils that slow down its biological decomposition due to inhibitory activity. Anaerobic digestion for biogas production seems to be a technically sustainable way to valorise by suitable pre-treatment methods. Present study shows extraction of essential oil in minimum requirement of water (1:1 w/v) for hydro-distillation that yields about 2% essential oil from fresh peels. Further, pre-treatment of left over de-oiled biomass with of 30% Fenton’s reagent treatment show biogas and methane production up to 322.63 ml biogas/g VS feed and 122.48 ml methane/g VS feed, respectively under mesophilic condition which is superior to conventional treatment

Noise pollution in Mumbai Metropolitan Region (MMR): An emerging environmental threat

Noise pollution in urban areas is an emerging environmental threat which local agencies and state authorities must consider in planning and development. Excessive noise is becoming a significant problem adversely affecting the physiological and psychological health of the citizens. Present study was carried out to assess and quantitatively evaluate ambient noise levels in Mumbai Metropolitan Region (MMR) consisting of 9 cities namely Bhiwandi-Nizampur, Kalyan-Dombivli, Mira-Bhayandar, Mumbai, Navi Mumbai, Panvel, Thane, Ulhasnagar and Vasai-Virar. The noise environment was assessed on the basis of equivalent continuous sound pressure levels (Leq), day-night noise levels (LDN) and noise limit exceedance factor (NEF) during day and night time of working and non-working days in four different area categories, viz. industrial, commercial, residential and silence zones. Present study shows that silence zones have been the worst affected areas where noise pollution levels and NEF indicate excessive violation of permissible noise limits due to unplanned, congested and unruly spaces for developmental and commercial activities, followed closely by residential and commercial zones. Cities with separate industrial and commercial zones showed less noisy surroundings in comparison with those cities where land use pattern of industrial and commercial zones is around or overlapping each other. It can thus be concluded that appropriate demarcation and planned use of city space is important to avoid exposure to rising noise pollution levels. Based on the noise pollution in (MMR), various control measures are suggested including awareness campaign and strict compliance of the rules and regulations