Existing biological nitrogen removal processes and current scope of advancement Sandip Magdum, V. Kalyanraman To cite this version: Sandip Magdum, V. Kalyanraman. Existing biological nitrogen removal processes and current scope of advancement. Research Journal of Chemistry and Environment, World Research Journals, 2017, 21 (7), pp.43-53. hal-01883538 HAL Id: hal-01883538 https://hal.archives-ouvertes.fr/hal-01883538 Submitted on 10 Oct 2018 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Research Journal of Chemistry and Environment____________________________________________Vol. 21 (7) July (2017) Res. J. Chem. Environ. Review Paper: Existing biological nitrogen removal processes and current scope of advancement Magdum Sandip1,2* and Kalyanraman V.2 1. Department of Technology, Savitribai Phule Pune University, Pune, INDIA 2. COE Biotechnology, R.D. Aga Research, Technology and Innovation Centre, Thermax Ltd., Pune, INDIA *[email protected] Abstract demand in natural water systems because nitrifying bacteria In India, to achieve the stringent norms of total will consume dissolved oxygen (DO) while oxidizing nitrogen less than 10 mg/l in sewage treatment plant is ammonia to nitrite and nitrate. Nitrate levels above 10 ppm may present a serious health concern for infants and a big challenge for the public - private facilities and 20 organizations. After successful implementation of this pregnant or nursing women . norm the pollutant burden from rivers and natural Also, the current scenario of wastewater treatment is facing water bodies certainly reduces. The use of conventional towards the development and use of energy efficient biological nitrogen removal (BNR) processes for new technologies. Method of pumping air into the wastewater is treatment facility development or retrofitting is also an defined as aeration process and it takes 55.6% of total energy energy and cost intensive practice. The process consumption in the wastewater treatment41. Further technologies offered by current market such as MLE, advanced treatment with nitrification required 40% more MBBR, IFAS and SBR are still in with downside of energy than conventional one15. In case of total nutrient higher footprint, multi tank reactors, heavy removal, anoxic recycling for denitrification with anoxic or instrumentation for IR and RAS which ultimately incur anaerobic mixing also increases the energy consumption. In higher capital and operating cost. The current market recent times, the novel biological nitrogen removal (BNR) mechanisms were identified such as Simultaneous Nitri- need and lack of sustainable nitrogen removal Denitrification (SND)25, Nitritation-Denitritation49 and applications, trigger to review the of all available Nitritation-Anaerobic Ammonium Oxidation efficient biological nitrogen removal processes. This (ANAMMOX)32 methods. These methods offer the review will gives an overall scenario of past and economically attractive and environmentally friendly current biological nitrogen removal process alternative to current wastewater treatment processes for the technologies with showing possible scope and way removal of fixed nitrogen29. forward towards more energy neutral nitrogen removal technologies. Current high rate wastewater treatment technologies include the moving bed biofilm reactor (MBBR) and integrated fixed Keywords: Nitrogen removal, sewage, footprint, energy, film activated sludge (IFAS) process. The MBBR is known sustainable for completely mixed, continuously operated, compact and 7,9,11 its simplicity of operation with major benefits of lower Introduction footprint, high degradation/reaction rate, nitrifiers retention Underground water is already overexploited in the United and its flexibility of operations at varying load. There are States, India and China and providing the water needed to also some process disadvantages of MBBR such as high feed a growing population and balancing this with all the operating cost, chemical requirement, settlers for sludge other demands on water, is one of the great challenges of this separation and high sludge production. These energies and century38. People living in river basins under severe water cost intensive limitations need to be minimized, to accept stress are projected to more than double between 2000-2050, MBBR as an ideal process. The MBBR used for high rate reaching 3.9 billion39. Almost one fifth of the world's COD or BOD removal applications and second reactor can population lacks the access to safe drinking water and this be attached for nitrification whereas the IFAS process can be water crisis is leading to cause of death and disease in the used for total nitrogen removal by using high hydraulic 38 retention time (HRT) and as efficient nitrogen removal world, with more than 14000 people dying each day . 65 Currently pressure for water is growing on natural systems processes with a sludge recycling cost . and urgent steps must be taken to begin to implement tried and tested methods of wastewater treatment before the The increasing demands of water and energy with increase situation gets out of control. With the organic pollutants, of population will be unavoidable whereas the energy fixed nitrogen such as ammonium and nitrate must be resources remain same. This paper reviews the current removed to avoid the eutrophication in water bodies. biological nitrogen removal processes used in wastewater treatment and scope for further sustainable development in nitrogen removal process. Lower NH3-N concentration at 1.68 mg/l also showed its toxic effect on fish flora52. Ammonia also imparts an oxygen 43 Research Journal of Chemistry and Environment____________________________________________Vol. 21 (7) July (2017) Res. J. Chem. Environ. Existing Processes of Biological Nitrogen nitrogen removal by 40%. Additionally, 25% of the aeration 62,70 Removal Conventional wastewater treatment systems for costs can be saved by avoiding nitrite oxidation . It is nitrogen removal require a lot of energy to create aerobic reported that combination of controlled aeration phase conditions for bacterial nitrification with use of organic length and DO at 15°C resulted in nitritation- denitritation carbon to remove nitrate by bacterial denitrification30. Major reactions under aerobic granular sludge in SBR, resulted in 33 biological nitrogen removal process reactions are as follows: total nitrogen removal efficiency of up to 95% . Similar studies on nitritation – denitritation were carried out in SBR Nitrification – Denitrification: Conventional nitrogen form of system with maximum 96% nitrogen removal with 13 removal process follows the nitrification- denitrification ammonia-rich landfill leachates . pathway (Figure 1a) where the autotrophic two step nitrification is carried by Nitrosomonas sp. and Nitrobactr Nitritation – ANAMMOX: Application of anaerobic sp. ammonium oxidizing (ANAMMOX) process for the treatment of high nitrogen strength wastewater is an Aerobic Denitrification: Simultaneous nitrification and emerging technology and scope for lower oxygen denitrification (SND) process occur concurrently in the same requirement. In the process (Figure 1c), aerobic ammonia aerobic reactor inside of floc structure (Figure 2) which oxidizing bacteria (AOB) oxidize half of the ammonia to remove 80 to 96 % nitrogen without additional carbon and nitrite which is used by ANAMMOX bacteria (Candidatus alkalinity requirement. The C:N ratio is required to be 10 and Brocadia fulgida) as electron acceptor for oxidizing the the bulk dissolved oxygen (DO) concentrations need to be remaining ammonia to dinitrogen gas2. maintained is between 0.3 mg/l to 0.7 mg/l25. The reaction depends on DO level, sludge size and diffusion barriers24. The quantitative analysis of oxygen consumption in a partial nitrification-ANAMMOX biofilm process16 and effect of Nitritation – Denitritation: The nitritation- denitritation granule size on autotrophic nitrogen removal66 was studied process is also called as “Nitrite Shunt” which avoids the in the ANAMMOX process. In 2014, the group of Delft oxidation of nitrite to nitrate by nitrite oxidizing bacteria University also reported the simultaneous partial nitritation (NOB) and allows for the reduction of the formed nitrite to and ANAMMOX process35 with physiological and kinetic dinitrogen gas by heterotrophic denitrification (Figure 1b). characterization of a suspended cell ANAMMOX reaction34. It would decrease the organic carbon demand for total Figure 1: Biological nitrogen removal reactions: a) Conventional biological nitrification and denitrification reaction, b) Nitrogen removal reaction by nitritation- denitritation process and c) Nitrogen removal reaction by ANAMMOX process 44 Research Journal of Chemistry and Environment____________________________________________Vol. 21 (7) July (2017) Res. J. Chem. Environ. Engineered biological nitrogen removal processes: Based on the known reactions many systems were engineered and applied for advance nitrogen removal in wastewater treatment.