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Influence of Nitrogen Loading Rate on impact of DEAMOX reaction for Sulphide and Organics DEAMOX processesтезисы доклада
- Авторы: Trukhina A., Gladchenko M., Kalyuzhnyi S.
- Сборник: Proc. of the 2nd International Conference “Hazardous and Industrial Waste Management
- Тезисы
- Год издания: 2010
- Место издания: Crete, Greece
- Первая страница: 79
- Аннотация: Wastewaters containing ammonia are generated by many industrial processes (e.g. food industry effluents, sludge liquor, manure flushings etc.). Discharging such wastewaters is a cause of toxic affect not only on aquatic organisms, but also on humans. Since the first observation of ANAMMOX (anaerobic ammonium oxidation) in an autotrophic denitrification reactor], numerous researches about the ANAMMOX -based conversion have been accomplished and other relating projects are still proceeding around the world over the last decade. Through ANAMMOX process, ammonium is converted into dinitrogen gas using nitrite as an electron donor in anaerobic condition (Eq.1) NH4+ + NO2- → N2 + 2Н2О (1) The advantages of these processes consist in no need in external carbon sources and oxygen as well as much smaller construction areas. These benefits make this process cost-effective compared to conventional nitrogen removal treatment (via nitrification-denitrification). Recent research on the Anammox process coupled to denitrification resulted in the development of the DEAMOX (DEnitrifying AMmonia OXidation) technology. In this process, the anammox reaction is combined with autotrophic denitratation using inorganic (e.g., sulphide, Eq.2) or organic (e.g., VFA, Eq.3) electron donor for the production of nitrite from nitrate within an anaerobic biofilm. NO3- + 0.25HS- à NO2- + 0.25SO42- + 0.25H+ (2) NO3- + 0.25CH3COO- à NO2- + 0.5HCO3- +0.25H+ (3) The DEAMOX-process configuration has several advantages compared to the most marketed configuration SHARON-ANAMMOX such as no complex process control is required for production of nitrite and the concentration of generated nitrite is much lower than the inhibitory level for the microorganisms involved. This process can also be applied for the industrial wastewater having a deficiency of organics but containing sulphide. The “ideal” simplified balance equations for sulphide or organics driven DEAMOX (reaction 1 + reaction 2 or 3) are the following: NO3- + 0.25HS- + NH4+ à N2 + 0.25SO42- +0.25H+ + 2H20 (4) NO3- + 0.25CH3COO- + NH4+ à N2 + 0.5HCO3- +0.25H+ + 2H20 (5) However, in reality, it is practically impossible to avoid denitritation in these systems: NO2- + 0.375HS- + 0.625H+ 0.5N2 + 0.375SO42- + 0.5H2O (6) NO2- + 0.375CH3COO- + 0.625H+ 0.5N2 + 0.75HCO3- + 0.5H2O (7) Thus, in the DEAMOX reactor, a strong competition for nitrite between ANAMMOX and denitritation is usually observed. For evaluation for outcome of such competition, the simple approach was elaborated. The full equations describing sulphide or organics driven DEAMOX process were suggested as: NO3- + (0.938-0.471)HS- + (0.125+0.881)NH4+ + (0.563-0.658)H+ + (0.625-0.251)HCO3- à (0.5+0.462)N2 + (0.125-0.063)C5H7NO2(denitrif.) + 0.062CH2O0.5N0.15(anammox) + (0.875+1.227)H2O (8) NO3- + (1.042-0.523)CH3COO- + (0.167+0.859)NH4+ + (0.625-0.689)H+ à (0.5+0.462)N2 + (1.25-0.69)HCO3- + (0.167-0.084)C5H7NO2(denitrif.) + 0.062CH2O0.5N0.15(anammox) +(1+1.164)H2O (9) Where – impact of DEAMOX reaction; thus, 1- – impact of full denitrification. In practice, can be roughly calculated from the experimentally measured ratio of consumed N-NH4+/consumed N-NOx- (r): = (r-0.125)/0.881 (for sulphide driven DEAMOX process) (4) = (r-0.167)/0.859 (for organic driven DEAMOX process) (5) In this paper, we investigated the influence of nitrogen loading rate (NLR) on impact factor of S- and O-DEAMOX processes. Both approaches for a stepwise increase of NLR were explored: i) the increase of influent substrate concentrations under the fixed hydraulic retention time (HRT) and ii) the decrease of HRT under the fixed influent substrate concentrations. The researches revealed that, the highest impact of DEAMOX reaction, 0.6, for S-DEAMOX process was reached under NLR of 725 mg N/l/d and the HRT of 0.51 d. At this regime also the highest removals of ammonia (84%), NOx- species (100%) and total N (93%) were observed. For O-DEAMOX process the highest impact of DEAMOX reaction, 0.7, was observed under NLR of 267 mg N/l/d and HRT of 0.71 d. The removals of ammonia, NOx- species and total N were accounted for 83, 81 and 82%, respectively. Further increase of NLR by means of increase of influent substrate concentrations led to decrease of impact of DEAMOX reaction till 0.24-0.35 and removal efficiencies of nitrogen species. The HRT didn’t show the significant influence on process performance.
- Добавил в систему: Гладченко Марина Анатольевна