Effect on Denitrification Efficiency in Alternating Process at Different C/N Ratio

2014 ◽  
Vol 1030-1032 ◽  
pp. 442-445
Author(s):  
Chun Di Gao ◽  
Wei Xiao Wang ◽  
Shi Xin Fan ◽  
Hao Li ◽  
Er Long Jiao
Keyword(s):  
Accumulation Rate ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Partial Nitrification ◽  
Biological Nitrogen Removal ◽  
Nitrite Accumulation ◽  
High Level ◽  
Biological Nitrogen ◽  
The Impact

Nitrification-denitrification biological nitrogen removal process has become the hotspot for the wastewater. During carbon/nitrogen (C/N) ratio was 1.16, 2.25, 4.07 and 6.20, the change of denitrification efficiency and the impact on the partial nitrification/denitrification was investigated. The results showed that removal rate of ammonia nitrogen was maintained in the high level, and was stable above 98% after C/N ratio higher than 1.16. With C/N ratio increased, the removal rate of chemical oxygen demand was increased about 20%, total nitrogen was increased from 54.9% to 84.6%. Simultaneously, after C/N ratio was higher than 4.07, the concentration of effluent TN was below 15 mg/L. Nitrite accumulation rate was maintained above 95%, the effect on partial nitrification was good, and the concentration of effluent nitrate was nearly 0, the best ratio of the C/N ratio was 4.07.

Effects of Alternating Oxic-Anoxic Model on Nitrite Accumulation in Biological Nitrogen Removal System

2014 ◽  
Vol 1030-1032 ◽  
pp. 422-425
Author(s):  
Er Long Jiao ◽  
Chun Di Gao ◽  
Hao Li ◽  
Wei Xiao Wang ◽  
Shi Xin Fan
Keyword(s):  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Ammonia Nitrogen ◽  
Biological Nitrogen Removal ◽  
Nitrite Accumulation ◽  
Total Nitrogen Removal ◽  
Cod Removal Rate ◽  
Biological Nitrogen ◽  
Removal System

The effects of chemical oxygen demand (COD), ammonia nitrogen, total nitrogen removal rates and nitrite accumulation are investigated under alternating oxic-anoxic model in biological nitrogen removal system——sequencing batch reactor (SBR). The system operational effect was studied by analyzing pollutants removal and nitrite accumulation changes. The results showed that the ammonium nitrogen removal rate increased gradually and reached 60% at last. The average removal rate of ammonia nitrogen was 50.2%. The average total nitrogen removal rate was 31.0% due to the low ammonia nitrogen removal and the low carbon in the inflow. The average COD removal rate was 41.7%, finally the COD removal rate reached near 60%. The average nitrite accumulation rate was 68.71%. The alternating oxic-anoxic model reached stable nitrite accumulation.

scholarly journals Partial Nitrification in a Sequencing Moving Bed Biofilm Reactor (SMBBR) with Zeolite as Biomass Carrier: Effect of Sulfide Pulses and Organic Matter Presence

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2484
Author(s):  
César Huiliñir ◽  
Vivian Fuentes ◽  
Carolina Estuardo ◽  
Christian Antileo ◽  
Ernesto Pino-Cortés
Keyword(s):  
Organic Matter ◽  
Sulfide Oxidation ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Biofilm Reactor ◽  
Partial Nitrification ◽  
Liquid Volume ◽  
Nitrite Accumulation ◽  
Moving Bed Biofilm Reactor ◽  
Moving Bed

This work aimed to achieve partial nitrification (PN) in a Sequencing Moving Bed Biofilm Reactor SMBBR with zeolite as a biomass carrier by using sulfide pulses in the presence of organic matter as an inhibitor. Two conditions were evaluated: sulfide (HS−) = 5 mg S/L and vvm (air volume per liquid volume per minute, L of air L−1 of liquid min−1) = 0.1 (condition 1); and a HS− = 10 mg S/L and a vvm = 0.5 (condition 2). The simultaneous effect of organic matter and sulfide was evaluated at a Chemical Oxygen Demand (COD) = 350 mg/L and HS− = 5 mg S/L, with a vvm = 0.5. As a result, using the sulfide pulse improved the nitrite accumulation in both systems. However, Total Ammonia Nitrogen (TAN) oxidation in both processes decreased by up to 60%. The simultaneous presence of COD and sulfide significantly reduced the TAN and nitrite oxidation, with a COD removal yield of 80% and sulfide oxidation close to 20%. Thus, the use of a sulfide pulse enabled PN in a SMBBR with zeolite. Organic matter, together with the sulfide pulse, almost completely inhibited the nitrification process despite using zeolite.

Partial Nitrification in Microaerobic Tank of “Anoxic-Anaerobic- Microaerobic-Aerobic (A2O2)” Biological Nitrogen Removal Process

2013 ◽  
Vol 295-298 ◽  
pp. 1039-1044 ◽  
Author(s):  
Jian Lei Gao ◽  
Bing Nan Lv ◽  
Yi Xin Yan ◽  
Jian Ping Wu
Keyword(s):  
Nitrogen Removal ◽  
Removal Rate ◽  
Pilot Scale ◽  
Partial Nitrification ◽  
Biological Nitrogen Removal ◽  
Nitrogenous Fertilizer ◽  
Removal Process ◽  
Batch Tests ◽  
N Removal ◽  
Biological Nitrogen

The pilot-scale Anoxic-Anaerobic-Microaerobic-Aerobic (A2O2) biological nitrogen removal process was used to treat the wastewater from nitrogenous fertilizer production with C/N ratio of 1~2. Batch tests were conducted to investigate the patial nitrification using the activated sludge from the microaerobic tank rich in nitrite bacteria as the experimental object. Results showed that 95% removal efficiency of NH3-N could be obtained with the HRT of 30 h. The SVI affected the NH3-N removal rate and the optimal SVI was 106 mL/g. The ORP was well correlated with the logarithm of NH3-N concentration with the linear regression equation of y=-57.233x+3.308. Moreover, the kinetic model for partial nitrification was determined as v=4.762s/(9.86+s).

scholarly journals Rapid cultivation and stability of autotrophic nitrifying granular sludge

2020 ◽  
Vol 81 (2) ◽  
pp. 309-320 ◽  
Author(s):  
Linan Zhang ◽  
Bei Long ◽  
Yuanyuan Cheng ◽  
Junfeng Wu ◽  
Binchao Zhang ◽  
...  
Keyword(s):  
Heterotrophic Bacteria ◽  
Accumulation Rate ◽  
Removal Rate ◽  
Granular Sludge ◽  
Ammonia Nitrogen ◽  
Nitrifying Bacteria ◽  
Structure Stability ◽  
Nitrite Accumulation ◽  
Term Operation

Abstract Autotrophic nitrifying granular sludge (ANGS) was cultivated by gradually decreasing the influent organics and adding exogenous nitrifying bacteria. Under the strategy, ANGS was domesticated within 36 days. Stability of the seed heterotrophic granules decreased significantly during conversion of organic wastewater to inorganic ammonia wastewater. Obvious granular breakage was observed during these days. However, the granular debris still had good settlement performance. With microbes gradually acclimated to the new environment, the debris provided a large number of carriers for the attached growth of the exogenous nitrifying bacteria, and they replaced the heterotrophic bacteria and became the dominant species. The domesticated ANGS showed good nitrification performance during the 37th to the 183rd day (ammonia nitrogen load between 0.28 and 0.29 kg/m3 · d). The removal rate of ammonia nitrogen was usually more than 95%, and nitrite accumulation rate was always larger than 50%. However, nitrification ability was gradually lost with the increase of the ammonia nitrogen load (0.3–0.64 kg/m3 · d) from the 184th day, and it almost approached the influent ammonia nitrogen at the 269th day. Interestingly, good structure stability of the ANGS was maintained during long-term operation, and the ANGS became smoother and denser at the end of the experiment.

scholarly journals Achieving Partial Nitrification via Intermittent Aeration in SBR and Short-Term Effects of Different C/N Ratios on Reactor Performance and Microbial Community Structure

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3485
Author(s):  
Zhengyao Zhou ◽  
Meixia Qi ◽  
Hongping Wang
Keyword(s):  
Ammonia Oxidation ◽  
Accumulation Rate ◽  
Batch Reactor ◽  
Ammonia Nitrogen ◽  
Partial Nitrification ◽  
Nitrite Accumulation ◽  
Intermittent Aeration ◽  
Reactor Performance ◽  
Short Term ◽  
Short Term Effects

A sequencing batch reactor (SBR) with an intermittent aeration mode was established to achieve partial nitrification (PN) and the short-term effects of C/N ratios were investigated. Stable nitrite accumulation was achieved after 107 cycles, about 56d, with the average ammonia nitrogen removal efficiency (ARE) and nitrite accumulation rate (NAR) of 96.92% and 82.49%, respectively. When the C/N ratios decreased from 4.64 to 3.87 and 2.32, ARE and NAR still kept a stable and high level. However, when the C/N ratio further decreased to 0.77, nitrite accumulation became fluctuation, and ARE, total nitrogen (TN), and chemical oxygen demand (COD) removal performance declined obviously. Except for four common phyla (Proteobacteria, Bacteroidetes, Chloroflexi, and Actinobacteria) in the wastewater treatment system, Patescibacteria, the newly defined superphylum, was found and became the most dominant phylum in the PN sludge for their ultra-small cell size. The only ammonia oxidation bacteria (AOB), Nitrosomonas, and nitrite oxidation bacteria (NOB), Nitrospira, were detected. The relative abundance of NOB was low at different C/N ratios, showing the stable and effective inhibition effects of intermittent aeration on NOB growth.

Characterization of slowly-biodegradable organic compounds and hydrolysis kinetics in tropical wastewater for biological nitrogen removal

2020 ◽  
Vol 81 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Seow Wah How ◽  
Jia Huey Sin ◽  
Sharon Ying Ying Wong ◽  
Pek Boon Lim ◽  
Alijah Mohd Aris ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Uptake Rate ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Hydrolysis Rate ◽  
Biological Nitrogen Removal ◽  
Tropical Region ◽  
Kinetic Coefficients ◽  
Wastewater Samples ◽  
Biological Nitrogen

Abstract Many developing countries, mostly situated in the tropical region, have incorporated a biological nitrogen removal process into their wastewater treatment plants (WWTPs). Existing wastewater characteristic data suggested that the soluble chemical oxygen demand (COD) in tropical wastewater is not sufficient for denitrification. Warm wastewater temperature (30 °C) in the tropical region may accelerate the hydrolysis of particulate settleable solids (PSS) to provide slowly-biodegradable COD (sbCOD) for denitrification. This study aimed to characterize the different fractions of COD in several sources of low COD-to-nitrogen (COD/N) tropical wastewater. We characterized the wastewater samples from six WWTPs in Malaysia for 22 months. We determined the fractions of COD in the wastewater by nitrate uptake rate experiments. The PSS hydrolysis kinetic coefficients were determined at tropical temperature using an oxygen uptake rate experiment. The wastewater samples were low in readily-biodegradable COD (rbCOD), which made up 3–40% of total COD (TCOD). Most of the biodegradable organics were in the form of sbCOD (15–60% of TCOD), which was sufficient for complete denitrification. The PSS hydrolysis rate was two times higher than that at 20 °C. The high PSS hydrolysis rate may provide sufficient sbCOD to achieve effective biological nitrogen removal at WWTPs in the tropical region.

scholarly journals Impact of Partially Treated Wastewater on Downstream Water Quality of Notwane River in Botswana

2018 ◽  
pp. 1-9
Author(s):  
Gilbert K. Gaboutloeloe ◽  
Gugu Molokwe ◽  
Benedict Kayombo
Keyword(s):  
Water Quality ◽  
Pearson Correlation ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Treated Wastewater ◽  
Nitrate N ◽  
River Stretch ◽  
Ph Range ◽  
The Impact

The impact of partially treated wastewater on the water quality of Notwane river stretch in the Gaborone region of Botswana was investigated. Water samples collected at effluent discharge point and three other sampling sites downstream were analyzed for pH, temperature, Biological Oxygen Demand (BOD5), Ammonia-nitrogen (Ammonia-N) and Nitrate-nitrogen (Nitrate-N). Sampling was conducted bi-weekly between February 2013 and April 2013. The ranges of measured parameters were:  pH (7.6-8.5), temperature (22-23ºC), BOD5 (11.2-27.0 mg/l), Ammonia-N (2.4-60.5 mg/l), Nitrate-N (20.6-28.6 mg/l). Analysis of variance, Games-Howel multiple comparisons and Pearson correlation were used to separate variable means. The results signal river non-point pollution due to runoff inflow of organics mainly from land use and domestic waste dumping by nearby dwellings. Temperature, BOD5, and pH range values were all within the Botswana Bureau of Standards (BOBS) limit while the maximum Ammonia-N and Nitrate-N were above BOBS limit by 50.5 mg/l and 6.6 mg/l, respectively. Regulations on indiscriminate waste dumping and discharge standards adherence should be enforced.

Vertical-flow constructed wetlands treating domestic wastewater contaminated by hydrocarbons

2015 ◽  
Vol 71 (6) ◽  
pp. 938-946 ◽  
Author(s):  
R. H. K. Al-Isawi ◽  
A. Sani ◽  
S. A. A. A. N. Almuktar ◽  
M. Scholz
Keyword(s):  
Positive Impact ◽  
Oxygen Demand ◽  
Aggregate Size ◽  
Ammonia Nitrogen ◽  
Flow Mode ◽  
Vertical Flow ◽  
Treatment Standards ◽  
Diesel Spill ◽  
The Impact ◽  
Outflow Concentration

The aim was to compare the impact of different design (aggregate size) and operational (contact time, empty time and chemical oxygen demand (COD) loading) variables on the long-term and seasonal performance of vertical-flow constructed wetland filters operated in tidal flow mode before and after a one-off spill of diesel. Ten different vertical-flow wetland systems were planted with Phragmites australis (Cav.) Trin. ex Steud. (common reed). Approximately 130 g of diesel fuel was poured into four wetland filters. Before the spill, compliance with secondary wastewater treatment standards was achieved by all wetlands regarding ammonia-nitrogen (NH4-N), nitrate-nitrogen (NO3-N) and suspended solids (SS), and non-compliance was recorded for biochemical oxygen demand and ortho-phosphate-phosphorus (PO4-P). Higher COD inflow concentrations had a significantly positive impact on the treatment performance for COD, PO4-P and SS. The wetland with the largest aggregate size had the lowest mean NO3-N outflow concentration. However, the results were similar regardless of aggregate size and resting time for most variables. Clear seasonal outflow concentration trends were recorded for COD, NH4-N and NO3-N. No filter clogging was observed. The removal efficiencies dropped for those filters impacted by the diesel spill. The wetlands system shows a good performance regarding total petroleum hydrocarbon (TPH) removal.

Effect of dosing regime on nitrification in a subsurface vertical flow treatment wetland system

2012 ◽  
Vol 66 (6) ◽  
pp. 1220-1224
Author(s):  
Suwasa Kantawanichkul ◽  
Walaya Boontakhum
Keyword(s):  
Continuous Flow ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Synthetic Wastewater ◽  
Experimental Unit ◽  
Vertical Flow ◽  
Treatment Wetland ◽  
Wetland System ◽  
Flow Treatment

In this study, the effect of dosing regime on nitrification in a subsurface vertical flow treatment wetland system was investigated. The experimental unit was composed of four circular concrete tanks (1 m diameter and 80 cm deep), filled with gravel (1–2 cm) and planted with Cyperus alternifolius L. Synthetic wastewater with average chemical oxygen demand (COD) and ammonia nitrogen of 1,151 and 339 mg/L was fed into each tank. Different feeding and resting periods were applied: continuous flow (tank 1), 4 hrs on and 4 hrs off (tank 2), 1 hr on and 3 hrs off (tank 3) and 15 minutes on and 3 hrs 45 minutes off (tank 4). All four tanks were under the same hydraulic loading rate of 5 cm/day. After 165 days the reduction of total Kjeldahl nitrogen and ammonia nitrogen and the increase of nitrate nitrogen were greatest in tank 4, which had the shortest feeding period, while the continuous flow produced the lowest results. Effluent tanks 2 and 3 experienced similar levels of nitrification, both higher than that of tank 1. Thus supporting the idea that rapid dosing periods provide better aerobic conditions resulting in enhanced nitrification within the bed. Tank 4 had the highest removal rates for COD, and the continuous flow had the lowest. Tank 2 also exhibited a higher COD removal rate than tank 3, demonstrating that short dosing periods provide better within-bed oxidation and therefore offer higher removal efficiency.

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