Prangya Ranjan Rout

A mechanistic approach to evaluate the effectiveness of red soil as a natural adsorbent for phosphate removal from wastewater

AbstractThe present study was conducted to investigate the efficacy of red soil (RS), as a natural adsorbent, for phosphate removal from wastewater. The chemical composition of the adsorbent was determined by proton-induced X-ray emission and proton-induced γ-ray emission methods. Apart from evaluating the influence of major experimental parameters, the equilibrium data were analyzed by different isotherm models and kinetic models. Experimentally obtained values, such as separation factor (RL), 0.0297, Freundlich exponent (n), 2.994, and Gibb’s free energy change (ΔG°), −1.279 kJ mol−1, suggest that the phosphate adsorption by RS was a favorable and spontaneous process. The presence of coexisting anions showed no competing effects on phosphate removal efficiency. For synthetic initial phosphate concentration of 20 mg L−1 and contact time of 90 min, phosphate removal efficiency was 96.47% in batch mode and 19 h of breakthrough time in column mode. Whereas with real domestic wastewater having 5.62 mg L−1 of...

Simultaneous removal of nitrogen and phosphorous from domestic wastewater using Bacillus cereus GS-5 strain exhibiting heterotrophic nitrification, aerobic denitrification and denitrifying phosphorous removal

A newly isolated GS-5 strain exhibiting heterotrophic nitrification, aerobic denitrification and denitrifying phosphorous removal was identified as Bacillus cereus GS-5 based on its phenotypic and phylogenetic characteristics. The isolate had exhibited efficient NH4+-N, NO3--N, NO2--N and PO43--P removal from nutrient spiked real domestic wastewater with average rates of 2.62, 2.69, 1.16 and 0.42mgL-1h-1, respectively under aerobic condition. Metabolic inhibitor based mass balance analysis indicated that dinitrogen gas (41%), intracellular nitrogen (29%) and intracellular phosphorous (60%) were the major fates of the initial NH4+-N and PO43--P. The successfully expression of hydroxylamine oxidase (hao), nitrate reductase (nar), nitrite reductase (nir) and poly phosphate kinase (ppk) enzyme in the cell free extracts and PCR amplification of nar, nir and ppk genes in the isolated strain provided further evidences for the nutrient removal possibility. A possible pathway of for nitrogen removal by GS-5 is suggested.

Development of an integrated system for the treatment of rural domestic wastewater: emphasis on nutrient removal

With the aim of enhancing the nutrient removal from rural domestic wastewater while reducing the cost of the treatment process, a novel, integrated treatment system consisting of a multi-stage bio-filter with drop aeration and a post positioned attached growth carbonaceous denitrifying bio-reactor was designed and developed in this study. The bio-filter was packed with ‘dolochar’, a sponge iron industry waste, as an adsorbent mainly for phosphate removal through a physicochemical approach. The denitrifying bio-reactor was packed with many waste organic solid substances (WOSS) as carbon sources and substrates for biomass attachment, mainly to remove nitrate in the biological denitrification process. The performance of the modular system, treating real domestic wastewater was monitored for a period of about 60 days and the average removal efficiencies during the period were as follows: phosphate, 99.48%; nitrate, 92.44%, ammonia, 96.64%, with mean final effluent concentration of 0.153, 5.5, and 1.06 mg L−1, respectively. This treatment system would allow multipurpose reuse of the final effluent. Moreover, the saturated dolochar can be used as a nutrient supply in agricultural practices and the partially degraded carbonaceous substances can also be used as an organic fertilizer after composting. Thus, the system displays immense potential for treating domestic wastewater significantly by decreasing the concentrations of nutrient and most importantly, facilitating the conversion of the waste materials into usable ones.

Assessing Possible Applications of Waste Organic Solid Substances as Carbon Sources and Biofilm Substrates for Elimination of Nitrate Toxicity from Wastewater

AbstractThis work aimed to find inexpensive alternatives that could serve both as carbon source and biofilm carrier for heterotrophic denitrification in treating nitrate contaminated waters. To asc...

Role of Bacillus cereus GS-5 strain on simultaneous nitrogen and phosphorous removal from domestic wastewater in an inventive single unit multi-layer packed bed bioreactor

This work evaluates the performance efficiency of a newly developed single unit packed bed bioreactor for nutrient removal from domestic wastewater. The packing materials, including dolochar, and a mixture of waste organic solid substance, were immobilized with a simultaneous nitrifying, denitrifying and phosphate removing bacterial strain, Bacillus cereus GS-5 and packed in the bioreactor alternatively in multiple layers. The bioreactor was operated continuously for a period of 70 days using both synthetic and real domestic wastewater (NH4+-N 30-100 mg/L, NO3--N 10-100 mg/L, PO43--P 5-20 mg/L and COD 250-1000 mg/L). The innovative single unit bioreactor exhibited simultaneous removal of NH4+-N (87.1-93.1%), NO3--N (69.4-88.4%), PO43--P (84-100%), and even COD (69.8-92.1%), in a remarkable disparity to traditional distinct aerobic-anaerobic treatment systems. This work advocated for a promising and feasible application prospect of the developed single unit packed bed bioreactor in domestic wastewater treatment emphasizing on nutrient removal.