Sustainable technologies for on-site domestic wastewater treatment: a review with technical approach

Environment, Development and Sustainability - The rapid population growth has rendered the centralized sewerage systems a non-realistic option in sparsely populated areas, particularly in...     

Model coupling approach for daily runoff simulation in Hamp Pandariya catchment of Chhattisgarh state in India

Environment, Development and Sustainability - Runoff estimation is of immense importance in hydrological analysis for water resource planning and management. The developing countries cannot afford...     

Increased UV-B radiation reduces N2-fixation in tropical leguminous crops

Net photosynthesis, leaf area, biomass, and number, size and activity of nodules were examined in three leguminous plants subjected under field conditions to supplemental UV-B radiation equivalent to a 15% ozone depletion at 25 degrees N latitude. Enhanced UV-B radiation adversely affected the net photosynthetic rate, growth characteristics and nodule activity in all three species. Maximum reduction in net photosynthesis occurred in Phaseolus mungo cv. Pant U-30, whereas the greatest reduction in nitrogenase activity occurred in Vigna radiata.     

Effects of fly ash, Pseudomonas striata and Rhizobium on the reproduction of nematode Meloidogyne incognita and on the growth and transpiration of pea

Glasshouse experiments were conducted twice to assess the ash amendments (0, 20, and 40% with soil), a phosphate solubilizing microorganism Pseudomonas striata and a root-nodule bacterium Rhizobium sp on the reproduction of root-knot nematode Meloidogyne incognita and on the growth and transpiration of pea. Amendments of fly ash with soil had no effect on transpiration. However, M. incognita reduced the rate of transpiration from 1st week onward after inoculation while inoculation of Rhizobium sp and P. striata increased transpiration from 1st week onward after their inoculation both in nematode inoculated and uninoculated plants. Increase in transpiration was greater when both organisms were inoculated together. Addition of 20 and 40% fly ash with soil was beneficial for plant growth both in nematode inoculated and uninoculated plants. Inoculation of above organisms also increases plant growth of nematode inoculated and uninoculated plants in different fly ash soil mixture but increase in growth was greater when both organisms were inoculated together. Use of 20% fly ash increased galling and nematode multiplication over plants grown in without fly ash while 40% fly ash had adverse effect on galling and nematode multiplication. Rhizobium sp had greater adverse effect on galling and nematode multiplication than P. striata. Use of both organisms together had greater adverse effect on galling and nematode multiplication than caused by either of them alone. Highest reduction in galling and nematode multiplication was observed when both organisms were used in 40% fly ash amended soil. However, highest transpiration was observed in plants without nematodes and inoculated with both organisms together both in with or without fly ash amended soil.     

Atmospheric depositions around a heavily industrialized area in a seasonally dry tropical environment of India

Clear and through-fall bulk depositions were collected in the downwind of a highly industrialized region in Sonbhadra district of India to estimate the influence of anthropogenic activities on chemical composition of depositions. Significant spatial and temporal variations in depositions of cations and anions were observed. Depositions were higher near the thermal power stations and coal mines as compared to distantly situated site. Seasonally summer samples showed maximum cation and anion depositions followed by winter and minimum in rainy season. The mean pH of the depositions indicates that rainfall in the area is alkaline. Among the anions, maximum deposition was recorded for SO4(2-) followed by NO3- and minimum for Cl-. Among the cations, Ca2+ deposition was maximum followed by NH4+. Na+, K+ and Mg2+ deposition rates showed more or less similar values. The depositions of cations and anions as well as pH were higher in through-fall than clear-fall samples. Results of the present study suggest that atmospheric depositions are strongly modified due to thermal power stations and coal mines in the area.     

A comparative study of cadmium phytoextraction by accumulator and weed species

Phytoextraction has shown great potential as an alternative technique for the remediation of metal contaminated soils. The objective of this study was to investigate cadmium (Cd) phytoextraction ability of high biomass producing weeds in comparison to indicator plant species. The pot study conducted with 10 to 200 mg Cd kg(-1) soil indicated that Ipomoea carnea was more effective in removing Cd from soil than Brassica juncea. Among the five species, B. juncea accumulated maximum Cd, but I. carnea followed by Dhatura innoxia and Phragmytes karka were the most suitable species for phytoextraction of cadmium from soil, if the whole plant or above ground biomass is harvested. In the relatively short time of this experiment, I. carnea produced more than 5 times more biomass in comparison to B. juncea. There were significant differences (p < 0.05) between the shoot length and shoot mass of control and treated plants.     

Semiconductor-mediated photocatalysed degradation of two selected priority organic pollutants,benzidine and 1,2-diphenylhydrazine,in aqueous suspension

The photocatalysed degradation of two selected priority organic pollutants, namely benzidine (1) and 1,2-diphenylhydrazine (DPH, 2) has been investigated in aqueous suspensions of titanium dioxide (TiO2) under a variety of conditions employing a pH-stat technique. The degradation was studied by monitoring the change in substrate concentration of the model compound employing HPLC analysis and the decrease in total organic carbon content, respectively, as a function of irradiation time. The degradation kinetics were studied under different conditions such as reaction pH, substrate and photocatalyst concentration, type of TiO2 photocatalyst and the presence of alternative additives such as H2O2, KBrO3 and (NH4)2S2O8 besides molecular oxygen. The degradation rates and the photonic efficiencies were found to be strongly influenced by the above parameters. Toxicity tests for the irradiated samples of benzidine measuring the luminescence of bacteria Vibrio fischeri after 30 min of incubation were also performed. 4-amino-biphenyl (7) and hydroquinone (13) were identified as intermediate products by GC/MS technique and probable pathways for the formation of the products are proposed.