Potential of wastewater grown algae for biodiesel production and CO2 sequestration

Algae have been proposed as a potential renewable fuel source. Photosynthetic CO2 fixation to substrates that can be converted to biodiesel by microalgae is thought to be a feasible technology with energy-saving and environment-friendly approach. In the present study, potential of microalgae, from wastewater stabilization pond, as a feedstock for biodiesel production and CO2 sequestration was evaluated. Mixed algae sample showed the highest CO2 fixation rate, followed by Chlorella sp., Scenedesmus incrassatulus, Scenedesmus dimorphus and Chroococcus cohaerens (2.807, 1.627, 1.501, 1.270 and 0.786 g L-1 d-1, respectively). Nile red stain was used for detection of lipid in microalgal sample which was further extracted and analysed by gas chromatography (GC). The main fatty acids present in the mixed algae sample were fatty acids with C14–C18 (>98%) that are generated after natural CO2 sequestration. At ambient CO2 concentration, total fatty acid methyl esters (FAME) mainly comprised of myristic acid (C14:0), 0.0718%; palmitic acid (C16:0), 2.558%; octadecenoic acid (C18:1), 28.98% and linoleic acid (C18:2), 12.54% which makes the microalgal biomass a suitable feedstock for biodiesel production and CO2 mitigation.Keywords: Biodiesel, carbon dioxide fixation, fatty acid profile, microalgae, wastewater stabilization pondAfrican Journal of Biotechnology Vol. 12(20), pp. 2939-294

In Vivo Studies to Elucidate the Role of Extracellular Polymeric Substances from Azotobacter in Immobilization of Heavy Metals

The role of extracellular polymeric substances (EPS) produced by the heavy metal-resistant strain of Azotobacter spp. in restricting the uptake of cadmium (Cd) and chromium (Cr) by wheat plants cultivated in soils contaminated with the respective heavy metals has been demonstrated. A heavy metalresistant strain of Azotobacter spp. was isolated and identified. Minimum inhibitory concentrations (MIC) of Cd2+ and CrO4 2- were determined to be 20 and 10 mg L-1, respectively. Under in vitro conditions, the EPS produced by the strain could bind 15.17 ( 0.58 mg g-1 of Cd2+ and 21.9 ( 0.08 mg g-1 of CrO4 2-. Fourier transform infrared spectra of the EPS revealed the presence of functional groups like carboxyl (-COOH)andhydroxyl (-OH), primarily involved in metal ion binding. Under pot culture experiments, the isolated strain of Azotobacter was added to the metal-contaminated soils in the form of free cells and immobilized cells. The total Azotobacter count and plant metal concentrations under different treatments showed a negative coefficient between the Azotobacter population and plant Cd (-0.496) and Cr (-0.455). Thus it could be inferred that Azotobacter spp. is involved in metal ion complexation either throughEPSor through cell wall lipopolysaccharides (LPS

Pulp and papermill wasterwater: can it solve the irrigation water scarcity problem

Changes in physico-chemical properties of soils and crops grown with pulp and paper mill wastewater in field lysimeters were carried out for three years at the integrated pulp and paper mill, madhya pradesh (india). lysimeters were prepared by excavating pits of 5 m x 2 m x 2 m, lined with polyethylene sheet and filled with sandy loam, clay and loamy sand soils and provided with percolate collection system. treated wastewater was used for crop irrigation containing high salinity and specific ion toxicity. with respect to sodium adsorption ration (sar), it was categorized under group `no restriction on use’. sandy loam & loamy sand soils in lysimeter i and iii percolate was 17% and 20% of irrigation while clay soil in lysimeter ii it was only 15%. sandy loam & loamy sand soils respectively showed 97 & 96% removal of chemical oxygen demand (cod) while clay soil removed 99% of cod and the color removal in both cases was 100%. percolate initially showed leaching of calcium and magnesium and retention of sodium, which got adsorbed in soil matrix. Application of wastewater resulted in increase in water holding capacity, ph (0.6 - 1.3 units), electrical conductivity of saturated extract (ece - 0.6 - 2.1 ms cm-1) and exchangeable sodium percent (esp - 8.1 - 11.6). organic carbon and available nitrogen, phosphorus and potash content of soils were also increasing. however, there was decrease in bulk density. the results showed that the application of wastewater increased the grain and straw yield of jowar, wheat and moong as compared to plain water respectively. there was slight variation in micro and macro nutrient content of grains of crop irrigated with wastewater, but it did not affect the nutrient quality and there was no accumulation of toxic heavy metals in the food grain. we measured nutrient input by wastewater and output by leaching and harvest export on unfertilized crop. a semi quantitative nutrient balance showed that all lysimeters had negative balance of micronutrients, indicating open nutrient cycles on these soils. these results showed that the pulp and paper mill wastewater might be successfully utilized for crop productio

Resource conservation through land treatment of municipal wastewater

Industrialization and urbanization have been causing tremendous pressure on the water resources. In turn, to maintain the pace of development, it has become necessary to search for alternative sources of water. Conventional wastewater-treatment technologies are cost-intensive and often pose financial constraint in developing countries. Therefore, considerable attention has been directed towards design and development of low-cost wastewater management technologies coupled with recycle and reuse benefits. High Rate Transpiration System (HRTS) is one such technology which can be implemented for domestic effluent disposal and reuse. This hypothesis was examined in field and laboratory experiments conducted by the National Environmental Engineering Research Institute (NEERI), Nagpur, India. This communication highlights the use of HRTS for the removal of pollutants like BOD, nitrogen and phosphorus from primary treated wastewater. The low-tech and low-cost wastewater treatment HRTS shows good performance for reduction of pollutants with minimal soil and plant contamination

Effect of amendment on phytoextraction of arsenic byVetiveria Zizanioides from soil

The present study was undertaken to evaluate the growth response of Vetiveria zizanioides amended with organic amendments to arsenic (As) in contaminated soils and its ability to sequester As. The test results indicate that the plants exhibited high tolerance to As in the soils and their normal growth continued even though As concentration reached 500 mg/kg. However, when As concentrations in soils were in the range of 1000~2000 mg/kg the plants could not survive no matter whether the soils were amended. The accumulation of As in roots (185.4 mg/kg) was higher than that in shoots (100.6 mg/kg). The As level in the contaminated soil was reduced from 500 mg/kg to 214 mg/kg after six months of As phytoextraction. Microbial population was not affected in the As contaminated soil amended with dairy sludge, mycorrhizae and Azotobacter

Land Capability Classification for Agro-economic Evaluation of Mahadayi Dam, Karnataka, India

This paper examines the socio-economic impact of proposed dam on cropland productivity of Mahadayi project, Karnataka, India. Systematic appraisal of dam and their designing by categories of classes on the basis of physical and chemical characteristics of soil has been done in favour of development of agronomic conditions for the study of proposed dam sites in Karnataka. The study is aimed at the effective utilization of land according to their classes. Documentation on the land capability classification is a versatile component in formulation effective land use planning before the construction of dam. Thus an attempt was made to evaluate dominantly occurring soils on four class’s viz. soil depth, soil texture, soil drainage and soil erosion. The study was focused on the evaluation of economics of crop production based on agro climatic condition of the study area and existing cropping pattern. This study is important as it explores how an input of water and nutrient would respond under variable climatic conditions. In addition,interactions of water supplies with fertilizer rates at optimizing these resources need have been investigated. This paper identifies key challenges and solutions for carrying out project-level economic analysis of adaptation to climate change, both stand-alone and integrated into broader development projects. Very few projects addressing adaptation thus far have been subject to in-depth and rigorous economic analysis for a variety of reasons, including a lack of guidance on how to deal with assessments of the impacts of climate change, as well as with estimating costs and benefits of adaptation under uncertainty. Our focus is on the agricultural sector, where the impacts of climate change have the potential to disrupt the livelihoods of rural populations in many regions and where adaptation must be given urgent consideration. Nevertheless, some of the approaches discussed are suitable to projects in other sectors

Effect of gypsum on moisture availability in vertisols under soybean gram sequence.

A field experiment entitled, effect of gypsum on moisture availability in Vertisols in under soybean–gram sequence was conducted during season of 2008-2009 at extra assistant director (EAD) farm, College of Agriculture, Nagpur. The field experiment was laid out in randomized block design (RBD) with seven treatments replicated thrice. Highest yield and moisture use efficiency in soybean were obtained 3 t gypsum ha-1 whereas 1.5 t gypsum ha-1 also increased yield and MUE of soybean over control. Increasing level of gypsum also increased the yield and MUE efficiency of gram. Reduction in water dispersible clay, ESP, pH, exchangeable sodium, Mg. Improvement in HC, exchangeable Ca and Ca/Mg ratio was found with higher level of gypsum but low level of gypsum i.e. 1.5 t ha-1 was also sufficient to give better result over control (no gypsum). Favourable changes in soil physical and chemical properties were mostly found in surface soil (0-30 cm) and in sub-soil (30-60 cm) effect was not significant. Increased in moisture storage in sub soil observed in gypsum applied plots over control. Result revealed that 1.5 t gypsum ha-1 was found sufficient to maintain enough electrolyte concentration and maintaining Ca/Mg ratio for improving H.C. and other physical properties resulted in better storage of moisture and increased in yield of soybean and gram

Treatment of waste gas containing low concentration of dimethyl sulphide in a high performance biotrickling filter

1018-1023A bench-scale biotrickling filter was operated in the laboratory for the treatment of dimethyl sulphide (DMS). The biotrickling filter was packed with pre-sterilized polyurethane foam and seeded with biomass developed from garden soil enriched with DMS. The biotrickling filter was operated for the generation of process parameters. The biotrickling filter could remove an average removal efficiency of 40.95 % at an effective bed contact time of 84 sec with an average loading rate of 0.56 mg/m3/h. Evaluation of microbiological status of the biotrickling filter indicated the presence of other bacterial cultures viz. Paenibacillus polymyxa, and Bacillus megaterium, besides Bacillus sphaericus.</i