Evaluation of upflow hybrid bioreactor system for treating low-strength nitrogenous wastewater under low-shear environment (original) (raw)
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Water Science and Technology, 2017
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Influence of Internal and External Recycle on Nitrogen Removal in Compact Bioreactor
2015
Internal Recycle ratios (IR) were alternated and operated to determine its efficiency on nitrate removal within a SMALL FOOTPRINT bioreactor. Determining a suitable recycle ratio is essential to justify the prerequisites required for operative optimization. In order to achieve considerable nitrogen reduction, the reactor was designed with primary (pre) and secondary (post) anoxic chambers, combined aeration chamber for nitrification and carbon removal and final settler to settle the biomass prior to discharge. The nitrate oxidized in aeration chamber was recycled back to the pre-anoxic chamber. The residual nitrate flows to the post anoxic chamber for denitrification. Each IR ratio of 6, 4 and 0, was operated with distinct influent Chemical Oxygen Demand (COD) to Total Kjeldahl Nitrogen (TKN) ratios of 18.9, 14.9 and 10.9, respectively. The IR of 6 with COD/TKN ratio of 18.9 attained maximum Total Nitrogen (TN) removal efficiency of 90.7%. The overall average total nitrogen (TN) = 4...
Iranian Journal of Environmental Health Science and Engineering, 2013
The lab-scale upflow anaerobic biofilm reactor was successfully operated for the treatment of synthetic wastewater with high nitrogen load by Anammox (anaerobic ammonium oxidation) process. During the entire period of operation, the reactor temperature was kept at 35±1°C. The operational strategy consisted of both increasing the ammonium and nitrite concentrations from 60 to 700mgN/L and from 80 to 920 mgN/L, respectively and decreasing the hydraulic retention time from 24 to 6 h, at each step. The highest achieved removal efficiency of ammonium and nitrite were 91 and 93%, respectively. Consequently, due to their acceptable performance for nitrogen removal in previous researches, modified Stover-Kincannon and Grau second-order models were used in this study. According to the experiment results, the model validity testing showed that the Stover-Kincannon model was a little more appropriate for the description of nitrogen removal in the reactor, even though both models gave high corr...
Nitrate removal in an innovative up-flow stirred packed-bed bioreactor
Chemical Engineering and Processing: Process Intensification, 2017
Highlights ï‚· An anaerobic up-flow stirred packed-bed reactor for nitrate removal is proposed. ï‚· Sludge carbonaceous material was used as support material. ï‚· High nitrate removal efficiency was achieved at very short space time. ï‚· Michaelis-Menten model was found to describe the denitrification process rather well at low initial nitrate concentration. ï‚· An effective and promising method for nitrate removal was demonstrated using a cheap and environmental friendly reactor.
International Journal of Environmental Science and Technology, 2011
In this research, a novel laboratory scale anaerobic/upflow sludge blanket filtration combined bioreactor was designed and operated to improve the efficiency of the upflow sludge blanket filtration process for the simultaneous removal of phosphorus and nitrogen from wastewater. The anaerobic/upflow sludge blanket filtration technique was developed by adding an anaerobic reactor to its influent and operated by varying the main process parameters in order to gain the optimum conditions. The results showed that biological removal efficiency of nitrogen and preservation of sludge blanket strongly depend on wastewater characteristics, hydraulic retention time, sludge age and process controlling parameters. The combined bioreactor performed a total nitrogen removal efficiency of 96.6 % with the sludge age of 25 days, total hydraulic retention time of 24 h and optimum "chemical oxygen demand/nitrogen/phosphorus" ratio of 100/ 5/1. This ratio also improved the compaction quality of sludge blanket in the upflow sludge blanket filtration clarifier. The average specific nitrification and denitrification rates occurred during the process can be expressed as 4.43 mg NOx-N produced/g VSS.d and 5.50 mg NOx-N removed/g VSS.d at the optimum ratio, respectively. To avoid sludge rising due to denitrification process, the optimum total hydraulic retention time of 16 to 24 h was achieved based on the effluent quality. This study suggested that the anaerobic/upflow sludge blanket filtration bioreactor at the optimum operational conditions can be an effective process for removal of nutrients from municipal wastewater.
Bioresource Technology, 2018
The feasibility of a continuous feed and intermittent discharge airlift bioreactor for simultaneous carbon and nitrogen removal from a low COD/N wastewater was evaluated. The effect of two independent variables, HRT (10-20 h) and NH 4 + /(NH 4 + +NO 3-) ratio (0.25-0.75), on the bioreactor performance was studied. The relatively high anaerobic to aerobic time ratio made an effective contribution to NH 4 + , NO 3-, and TN removal. TN removal was enhanced with increase in HRT and decrease in NH 4 + /NH 4 + +NO 3 and at the optimum condition, 616 mg/L (88%) and 213 mg/L (76%) of sCOD and TN were removed, respectively. The results suggested that the nitrogen removal process was based on a combination of anaerobic ammonium oxidation (Anammox), simultaneous nitrification-denitrification (SND), and presumable dissimilatory nitrate reduction to ammonium (DNRA) mechanisms.
The paper deals with the results obtained as nitrogen removal in a platform for the treatment of industrial liquid wastes. The reaching of the optimal reduction percentages was related, at first, with the choice of a flexible treatment flow scheme characterized by the application of best available technologies. The advanced alternate cycles process in the biological reactor determined, after three months of experimental work, removal performances on average equal to 97% for the ammonia and 77% for TN. Moreover, the best nitrification results were achieved despite the complex mixtures of different chemical species in the main influent that can inhibit the NH4-N reduction. The ammonia uptake rate measured was 0.112 kgNOx-NkgVSS -1 d-1 at 20 °C. The denitrification process was assured also at COD/TN condition lower than 5.
Water, Air, & Soil Pollution, 2019
Both domestic and industrial effluent treatments contain or produce nitrogen loading during the treatment process. It is important to seek the removal of nitrogen while maintaining the design of existing systems, which are usually composed by the association of anaerobic and aerobic reactors. Thus, in this research, an anaerobic filter (AF) and an upflow anaerobic sludge blanket (UASB) reactors were fed with synthetic effluent enriched with nitrate to compare how these reactors would behave if they became denitrifying reactors. With the application of 100.0 mg NO 3 −-NL −1 , the AF presented better efficiency. With respect to the biogas production, the composition was significantly altered: from CH 4 and CO 2 concentrations close to 70% and 13% without NO 3 N addition to N 2 concentration higher than 85% with addition of 100.0 mg NO 3 −-NL −1. The UASB hydrodynamic profile was modified due to an increase in the mixing behavior along the denitrification stages by biogas production. This was not observed in the AF due to the presence of the support media, which was also responsible for ensuring a greater capacity to withstand denitrification without organic matter being carried out of the system.
Environmental Engineering Science, 2010
Discharge of nitrogenous components to water bodies can cause eutrophication, deterioration of water quality, toxicity to aquatic life, and pose a potential hazard to human and animal health. Biological nitrogen removal can remove nitrogenous components via conversion to harmless nitrogen gas with high efficiency and relative low costs. However, the removal of nitrogen from domestic wastewater with a low carbon=nitrogen (C=N) ratio can often be limited in municipal wastewater plants (WWTPs) because organic carbon is a limiting factor for denitrification. The present work reviews innovative bacterial nitrogen removal pathways such as shortcut nitrification=denitrification, simultaneous nitrification=denitrification, and the nitritation Anammox process, which can remove nitrogen with low or zero dosage of organic carbon sources. We conclude that advanced process control and some new biological treatment processes including the modified anaerobic=anoxic=oxic (A 2 =O) process, the step-feed multistage an-aerobic=oxic (A=O) process, and new reactors like the membrane bioreactors (MBRs) and the membrane-aerated biofilm reactors (MABRs) can support the innovative biological nitrogen removal pathways. They can effectively be used for nitrogen removal from low C=N domestic wastewater without external carbon addition. In addition, conventional and alternative carbon sources for enhanced biological nitrogen removal were also reviewed. We conclude that alternative carbon sources such as wine distillery effluent, the leachate of food waste, digested piggery manure, hydrolyzed molasses, biologically hydrolyzed or mechanically disintegrated sludge offer the same or better performance for nitrogen removal at reduced costs. Finally, we suggest that (1) these new processes and technologies are implemented at large scale for nitrogen removal from low C=N domestic wastewater, (2) further method logic are explored to introduce the Anammox pathway into domestic wastewater treatment, and (3) alternative carbon sources are explored and optimized for supporting the denitrification. With these efforts, cost-effective nitrogen removal from low C=N ratio domestic wastewater can be obtained in the near future.