NEW TRENDS IN AMMONIA NITROGEN REMOVAL FROM WASTEWATER: NITRITATION – ANAMMOX AT LOW TEMPERATURE

Partial nitrification (nitritation) – anammox (anaerobic ammonia oxidation) process is increasingly used to treat wastewater, characterized by a high nitrogen content and high temperature (25 - 40°C). It is connected with the optimal temperature of anammox bacteria, which is at the range between 30 and 40°C. Mainstream application of anammox for the municipal wastewater, characterized by lower temperature seems to be one of the most challenging, but profitable process. Thenceforth, the research performed in the field of the nitritation – anammox at low temperature (10 - 20°C) become more and more intense. Compared with the conventional nitrification – denitrification system, nitritation – anammox reduces oxygen demand, eliminates the need for organic carbon source and produces less excess sludge. As a result, it allows to a significant cost reduction. This paper reviews the most important and recent information in the field of nitritation – anammox process at low temperature. Effective nitrogen removal from the municipal wastewater was demonstrated at 15°C in a pilot scale and at 12°C in a laboratory scale reactor. The best performance is achieved in sequencing batch reactors and moving bed reactors with biofilm or granular biomass, as well as combinations of these technologies. Molecular biology studies shows that anammox bacteria of the genus Candidatus Brocadia may have the biggest predispositions to adapt to low temperature. However, temperature about 10°C, time and method of biomass adaptation are still the main challenges for stable and common nitritation – anammox process

Comparative study on different Anammox systems

The legal requirements for wastewater discharge into environment, especially to zones exposed to eutrophication, lately became stricter. Nowadays wastewater treatment plants have to manage with the new rules and assure better biogenic elements’ removal, in comparison with the past. There are some well-known methods of diminishing concentrations of these compounds, but they are ineffective in case of nitrogen-rich streams, as landfill leachate or reject waters from dewatering of digested sludge. This wastewater disturbs conventional processes of nitrification-denitrification and raise necessity of building bigger tanks. The partial nitritation followed by Anaerobic Ammonium Oxidation (Anammox) process appear to be an excellent alternative for traditional nitrification/denitrification. The process was investigated in three different reactors – Membrane Bioreactor (MBR), Moving Bed Biofilm Reactor (MBBR) and Rotating Biological Contactor (RBC). The process was evaluated in two options: as a two-stage process performed in two separate reactors and as a one-stage process. The two-step process, in spite of very low nitrogen removal rates, assured very high nitrogen removal efficiency, exceeding even 90% in case of the MBBR. However, obtained results revealed that the one-step system is a better option than the two-step system, no matter, what kind of nitrogen-rich stream is taken into consideration. Moreover, the one-step process was much less complicated in operation. Performed research confirmed a hypothesis, that the oxygen concentration in the bulk liquid and the nitrite production rate are the limiting factors for the Anammox reaction in a single reactor. In order to make a quick and simple determination of bacteria activity, the Oxygen Uptake Rate (OUR) tests were shown as an excellent tool for evaluation of the current bacteria activity reliably, and without a need of using expensive reagents. It was also shown, that partial nitritation/Anammox process, could be successfully applied at temperatures much lower than the optimum value. Performed Fluorescent in situ Hybridization (FISH) analyses, proved that the Anammox bacteria were mainly responsible for the nitrogen removal process.QC 2010070

NEW TRENDS IN AMMONIA NITROGEN REMOVAL FROM WASTEWATER: NITRITATION – ANAMMOX AT LOW TEMPERATURE

Partial nitrification (nitritation) – anammox (anaerobic ammonia oxidation) process is increasingly used to treat wastewater, characterized by a high nitrogen content and high temperature (25 - 40°C). It is connected with the optimal temperature of anammox bacteria, which is at the range between 30 and 40°C. Mainstream application of anammox for the municipal wastewater, characterized by lower temperature seems to be one of the most challenging, but profitable process. Thenceforth, the research performed in the field of the nitritation – anammox at low temperature (10 - 20°C) become more and more intense. Compared with the conventional nitrification – denitrification system, nitritation – anammox reduces oxygen demand, eliminates the need for organic carbon source and produces less excess sludge. As a result, it allows to a significant cost reduction. This paper reviews the most important and recent information in the field of nitritation – anammox process at low temperature. Effective nitrogen removal from the municipal wastewater was demonstrated at 15°C in a pilot scale and at 12°C in a laboratory scale reactor. The best performance is achieved in sequencing batch reactors and moving bed reactors with biofilm or granular biomass, as well as combinations of these technologies. Molecular biology studies shows that anammox bacteria of the genus Candidatus Brocadia may have the biggest predispositions to adapt to low temperature. However, temperature about 10°C, time and method of biomass adaptation are still the main challenges for stable and common nitritation – anammox process

Wpływ nanocząstek tlenku manganu (MnO2) na aktywność procesów nitryfikacji i anammox

The anammox (anaerobic ammonia oxidation) process is one of the most efficient processes of nitrogen removal from wastewater. Although there are some applications of anammox-based technologies, it is still difficult to apply this process widely because of the high optimal temperature around 30–40°C. Thus, the main objective of this study was to evaluate the short-term effects of MnO2 on the anammox and nitrification process activity at a wide range of temperatures between 10 and 30°C, using statistical methods based on the central composite design (CCD). The influence of MnO2 on anammox and nitrification activity, suspended biomass from the laboratory-scale sequencing batch reactor (SBR), and activated sludge from WWTP, respectively, was used. MnO2 concentration range was set between 15 and 85 mg/L, and the temperature range was set between 10 and 30°C. Anammox and nitrification process activity was measured based on the batch test and oxygen uptake rate (OUR), respectively. The results were statistically analyzed. Results revealed that nanoparticles can slightly improve anammox activity by several percent, by up to 10%, but in most cases MnO2 influence was insignificant. The optimal concentration for the anammox stimulation at temperatures below 20°C was evaluated between 40 and 60 mg/L, corresponding to 36 and 56 mg/g VSS. Manganese oxides contribution in the nitrogen removal processes was proved and they should be considered in the field of the anammox process. Thus, further studies are suggested to investigate the long-term effects of MnO2 on the low-temperature anammox process, overcoming possibility of inhibition.Proces anammox (beztlenowe utlenianie amoniaku) jest procesem efektywnego usuwania azotu ze ścieków. Pomimo, że istnieje wiele technologi wykorzystujących proces anammox, jego zastosowanie nadal jest ograniczone ze względu na wysoką optymalną temperaturę (około 30–40°C). W związku z tym, celem tej pracy była ocena krótkoterminowego wpływu MnO2 na aktywność procesów anammox i nitryfikacji w zakresie temperatur od 10 do 30°C, przy użyciu metod statystycznych. Do badań wykorzystano biomasę anammox pobraną z laboratoryjnego sekwencyjnego reaktora porcjowego oraz biomasę bakterii nitryfikacyjnych pochodzącą z komunalnej oczyszczalni ścieków. Badania prowadzono przy zastosowaniu stężeń MnO2 z zakresu od 15 do 85 mg/l oraz temperatur pomiędzy 10–30°C. Aktywność procesu anammox zbadano przy pomocy testów porcjowych, natomiast do zbadania aktywność procesu nitryfikacji wykorzystano pomiar szybkości zużycia tlenu. Wyniki wykazały, że nanocząstki MnO2 mogą poprawić aktywność procesu anammox o kilka procent (nawet o 10%). Optymalne stężenie MnO2 dla stymulacji procesu anammox w temperaturach poniżej 20°C wynosiło między 40 a 60 mg/l, co odpowiada 36 i 56 mg/g s.m.o. Niniejsze badania udowadniają, że dodatek MnO2 może powodować wzrost aktywności procesu anammox przy jednoczesnym obniżeniu temperatury. Dlatego sugeruje są dalsze badania w celu zbadania długoterminowego wpływu nanocząstek MnO2 na niskotemperaturowy proces anammox

Performance of the anammox sequencing batch reactor treating synthetic and real landfill leachate

The anaerobic ammonium oxidation (anammox) process is one of the most energy efficient and environmentally-friendly bioprocess for the treatment of the wastewater with high nitrogen concentration. The aim of this work was to study the influence of the high nitrogen loading rate (NLR) on the nitrogen removal in the laboratory-scale anammox sequencing batch reactor (SBR), during the shift from the synthetic wastewater to landfill leachate. In both cases with the increase of NLR from 0.5 to 1.1 – 1.2 kg N/m3d, the nitrogen removal rate (NRR) increases to about 1 kg N/m3d, but higher NLR caused substrates accumulation and affects anammox process efficiency. Maximum specific anammox activity was determined as 0.638 g N/g VSSd (NRR 1.023 kg N/m3d) and 0.594 g N/g VSSd (NRR 1.241 kg N/m3d) during synthetic and real wastewater treatment, respectively. Both values are similar and this is probably the nitrogen removal capacity of the used anammox biomass. This indicates, that landfill leachate did not influence the nitrogen removal capacity of the anammox process

Adsorption of oxytetracycline and ciprofloxacin on carbon-based nanomaterials as affected by pH

With the increase in use and application of carbon nanomaterials and the frequent presence of fluoroquinolones and tetracyclines antibiotics in the aquatic environment, their interactions have attracted extensive attention. In this study, adsorption of two antibiotics: oxytetracycline (OTC) and ciprofloxacin (CIP) by four carbon-based nanomaterials (graphene oxide, reduced graphene oxide, multiwalled carbon-nanotubes, oxidized multiwalled carbon-nanotubes) affected by pH was investigated. The experiment was performed in two steps: (i) adsorption of OTC and CIP at different pH values, (ii) adsorption isotherm studies of both antibiotics on four carbon-based nanomaterials. Both steps were conducted using the batch equilibration technique. The results showed that the adsorption of both antibiotics on studied adsorbents was highly pH-dependent. The highest adsorption was obtained at pH 7.0, implying the importance of the zwitterionic antibiotics forms to adsorption. Antibiotics adsorption isotherms at three given pH values followed the order of pH 7.0 > 1.0 > 11.0, which confirmed zwitterionic species of OTC and CIP as having the greatest ability to adsorb on carbonaceous nanomaterials. Electrostatic interaction, π-π EDA interaction, hydrophobic interaction for both antibiotics, and additionally hydrogen bond for CIP were possible mechanisms responsible for OTC and CIP adsorption onto studied nanomaterials. These results should be important to understand and assess the fate and interaction of carbon-based nanomaterials in the aquatic environment. This study can also be important for the use of carbon nanomaterials to remove antibiotics from the environment

Performance of the anammox sequencing batch reactor treating synthetic and real landfill leachate

The anaerobic ammonium oxidation (anammox) process is one of the most energy efficient and environmentally-friendly bioprocess for the treatment of the wastewater with high nitrogen concentration. The aim of this work was to study the influence of the high nitrogen loading rate (NLR) on the nitrogen removal in the laboratory-scale anammox sequencing batch reactor (SBR), during the shift from the synthetic wastewater to landfill leachate. In both cases with the increase of NLR from 0.5 to 1.1 – 1.2 kg N/m3d, the nitrogen removal rate (NRR) increases to about 1 kg N/m3d, but higher NLR caused substrates accumulation and affects anammox process efficiency. Maximum specific anammox activity was determined as 0.638 g N/g VSSd (NRR 1.023 kg N/m3d) and 0.594 g N/g VSSd (NRR 1.241 kg N/m3d) during synthetic and real wastewater treatment, respectively. Both values are similar and this is probably the nitrogen removal capacity of the used anammox biomass. This indicates, that landfill leachate did not influence the nitrogen removal capacity of the anammox process