Microbial mediated anoxic ammonia removal in the presence of granulated nanoscale oxyhydroxides of Fe (GNOF) was investigated in a SBR, as a novel alternative to conventional nitrification and denitrification. Activated sludge flocs collected from a SBR treating sewage was used as seed biomass to develop the process. After confirming the feasibility of anoxic ammonia removal, SBR operations were carried out for 267 days in 9 phases by varying the initial NH4 +-N concentrations from 100 to 500 mg/L and cycle time from 2 to 0.5 day. Effective anoxic ammonia removal was achieved in 0.5 day cycle time with the removal rates of NH4 +-N and TN as 130 mg/L/d and 115 mg/L/d, respectively. Batch studies showed that the optimum COD/NH4 +-N ratio for effective NH4 +-N removal was less than or equal to 2. The kinetics of NH4 +-N removal, confirmation studies for GNOF coupled nitrification-denitrification and Fe redox cycling involved in the process were also performed and discussed. The developed process is economical as there is no need for aeration and alkalinity. © 2018 Elsevier Ltd.

Sabumon  Pothanamkandathil Chacko

School of Civil Engineering

Chennai Campus

Desireddy S

Maliyekkal S.M.

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Journal of Environmental Chemical Engineering

This paper describes a chitosan template assisted synthesis of nanocrystalline aluminium oxyhydroxide (γ-AlOOH) at an ambient temperature (30 ± 2 °C) and atmospheric pressure. High ability of the composite in removing fluoride from water has been demonstrated. The structural, morphological and compositional characteristics of the composite were studied using various spectroscopic and microscopic techniques. The results showed that the composite has nanoarchitecture comprising a number of γ-AlOOH nanoparticles of size less than 10 nm attached to the fibrils of chitosan. Batch and continuous flow adsorption experiments were conducted to assess the parameters that influence the adsorption process. The parameters investigated include contact time, initial fluoride concentration, adsorbent dose, pH of the solution, co-existing ions in water, and size of the adsorbent granules. The composite showed good affinity to fluoride and the maximum uptake capacity was 13.47 (mg/g) (mg/L)-1/n as described by Freundlich isotherm model. The kinetics of adsorption was affected by the size of the granules and the kinetic data followed pseudo-second-order rate equation. Except bicarbonate and sulfate, other competing ions studied did not affect the uptake of fluoride significantly. The high affinity to fluoride, simple and eco-friendly synthesis approach demonstrate the utility of the material for defluoridation of water. © 2014 Elsevier Ltd. All rights reserved.

A low cost approach to synthesize sand like AlOOH nanoarchitecture (SANA) and its application in defluoridation of water

Enhanced simultaneous partial nitrification, anammox and denitrification (SNAD) process was developed using a 2.4 L down-flow packed bed reactor for removing higher concentrations of ammonia and chemical oxygen demand (COD) (at COD/NH4-N ratio = 1.0) in low dissolved oxygen concentrations (≤0.35 mg/L). SNAD was developed using flocculent type activated sludge sourced from a tannery common effluent treatment plant and the reactor was operated continuously for 122 d at various loading rates with hydraulic retention time (HRT) varied between 12 h and 3 h. The reactor was operated in room temperature and the liquid temperature varied between 28 and 32 °C. The performance of the reactor at 3 h HRT showed enhanced removal rates of NH4-N (2.8 g/L d), total nitrogen (2.5 g/L d) and COD (4.9 g/L d) at ammonia and COD loading rates of 5.4 g/L d. The nitrogen removal was due to the competitive involvement of anammox (∼50%) and denitrification (∼50%) and these processes were confirmed by conducting separate batch experiments. There was no external addition of alkalinity at higher loading rates corresponding to the requirement of oxidation of NH4-N. This study demonstrates SNAD for enhanced rate of removals of NH4-N and COD at high concentrations compared to the reported results in literature and indicates a potential application. © 2015 Elsevier Ltd. All rights reserved.

Development of enhanced SNAD process in a down-flow packed bed reactor for removal of higher concentrations of NH4–N and COD

This work describes development of a microbial consortium dominant in anammox in presence of organic carbon (available through cell lyses) by employing simple sequencing batch operation in 23 cycles exceeding 400days. Seed biomass from a tannery Common Effluent Treatment Plant (CETP) was enriched for anammox and attained maximum removals of NH4-N (95%) and NO2-N (98%). The anammox was confirmed by nitrogen mass balance in a controlled batch experiment and by DNA extraction-PCR-agarose gel electrophoresis. The effective anammox followed first order reaction kinetics with rate constant of 0.0141/h and half-saturation constant of 10.6mg/L. Evidence for coexistence of denitrification (99% NO2-N removal) and anammox (57.8% NH4-N removal) was demonstrated. This study opens-up possible application of microbial consortium dominant in anammox for simultaneous removal of ammonia and organic carbon from wastewaters.

Journal	Data powered by TypesetJournal of Environmental Chemical Engineering
Publisher	Data powered by TypesetElsevier BV
ISSN	2213-3437
Open Access	No