Removal Efficiencies Of NH3-N Research Articles

CONTROL STRATEGIES OF NITRITE ACCUMULATION IN A SUBMERGED BIOFILTER

Short-cut nitrification under various Nitrogen Loading Rate (NLR), dissolved oxygen (DO) concentrations and pHs at a constant temperature of 25 ±1 0C was investigated in a submerged biofilter reactor. The lowest NO2-N/NOx-N ratio was observed when the NLR was up to 160 g/m3·day. Further increase the NLRresulted in incomplete oxidation of ammonium and the effluent NH4-N and NO2-N concentration increased. Although the highest NO2-N/NOx-N ratio of 0.61 was achieved, the NH4-N removal efficiency was drastically dropped to 48% at the NLR of 294 g NH4-N/m3.day. The highest NO2-N/NOx-N ratio of 0.68 was achieved at the pH of 9.0 and 1.0 mg O2/l. However, NN4-N removal efficiency and the NO2-N/NOx-N ratio were sharply dropped to 33% and 0.55 by getting the NLR to 381 g NH4-N/m3⋅day at the DO concentrations of 2.0 mg/l. Key words: partial nitrification, NO2-N/NOx-N ratio.

Effect of temperature on the wastewater treatment of a novel anti-clogging soil infiltration system

Effects of temperature (7°C, 13°C, 18°C, 25°C and 33°C) on the treatment of wastewater by a novel soil wastewater infiltration system (SWIS) and its properties were investigated in this study. The results showed that low temperatures had negative effects on the pollutants removal. Removal efficiencies of the pollutants increased with the temperature increasing throughout the overall experimental operation period. Taking the temperature and removal efficiency into consideration, when the temperature was about 33°C, the removal efficiencies of COD, NH3-N, TN, and TP in soil column were 98.3%, 97.1%, 85.0%, and 96.0%, respectively. Overall, 50 weeks of lab-scale tests indicated that the robustness of the SWIS in terms of achieving very high quality of treated water was very well when the operation temperature was higher than 13°C. In addition, the ORP values decreased from top to bottom of the soil column during the experimental process, while the pH values increased. This study will guide the decision on a pilot-scale SWIS application in the campus area.

Nitrogen removal efficiency of an A2/O bio-reactor treating domestic sewage mixed with landfill leachate and fecal sewage

A set of anaerobic-anoxic-aerobic (A2/O) bio-reactor system was used to treat domestic sewage mixed with landfill leachate and fecal sewage in Datansha Sewage Treatment Plant in Guangzhou China. The experiment investigated the optimal mixing proportion of treating landfill leachate, fecal sewage mixed with domestic sewage synchronously and the optimal running conditions for the removal efficiency of nitrogen by an orthogonal array test. A confirmatory experiment was also carried out to verify the optimal parameters obtained by the orthogonal array test. The results showed that: the optimal volume ratio of landfill leachate, fecal sewage and urban wastewater in the A2/O process was 1:3.75:1000. The average removal efficiency of NH3-N, TN and COD can reach 96%, 61% and 85% respectively under the conditions of hydraulic retention time (HRT) of 11h, dissolved oxygen (DO) of 3 mg L-1 the mixed-liquid return ratio (r) of 200% and sludge return ratio (R) of 80%.

Effect of different temperatures on performance and membrane fouling in high concentration PAC–MBR system treating micro-polluted surface water

A bench-scale immersed microfiltration coupled with 50 g/L PAC was developed to treat micro-polluted surface water (MPSW) under 10 and 20 °C and the effects of temperatures on the performance and the membrane fouling were also investigated. The low temperature (10 °C) delayed the time for the start-up by 9 days and the complete nitrification by 10 days. In the stable operation, two systems both had high NH₃-N removal efficiency (above 90%) and better removal of organic matters (10% DOC, 5% UV₂₅₄ and 4% SUVA) at 10 °C. Polysaccharides (SMP) were the main membrane fouling matters at low temperature (10 °C) and low temperature (10 °C) didn't cause serious chemical irreversible membrane fouling.

Partial Nitrification in Microaerobic Tank of “Anoxic-Anaerobic- Microaerobic-Aerobic (A<sub>2</sub>O<sub>2</sub>)” Biological Nitrogen Removal Process

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).

Performance of Membrane Bioreactor (MBR) in High Phosphate Wastewater

This study presents the performance of membrane bioreactor in treating high phosphate wastewater. The laboratory scale MBR was operated at permeate flux of 25 L/m2.h with a hollow fiber membrane (polypropylene, approx. pore size 0.01 - 0.2 μm) at hydraulic retention time (HRT) of 12 hrs. Scanning electron microscopy (SEM) and energy diffusive X-ray (EDX) analyzer were used to characterize the membrane foulants. Results showed that the removal efficiencies of COD, TSS, NH3-N and PO4 3- were 93, 98, 80 and 30% respectively. On average 91% of influent soluble microbial products (SMP) were eliminated, with the eliminations of polysaccharides mostly above 80%. The main fouling resistance was cake resistance. It should be noted that SMP were found in major portions of mixed liquor that played a relatively significant role in membrane fouling. SEM and EDX analyses indicated that the foulants covering the membrane surfaces comprises not only organic substances but also inorganic elements including Mg, Ca, Al, K and P.

Application of Chemical Precipitation in Treating Ammonia Nitrogen from Excess Sludge Liquor

Removal effect of NH3-N by chemical precipitation process was studied in treating excess sludge liquor (the NH3-N concentration 600~1000mg/L) produced from a municipal wastewater treatment plant. MgSO4 and Na2HPO4 were used as the precipitants to investigate the influences of initial pH, reaction time and the precipitants dosage on the NH3-N removal effect as well as the concentration of residual TP. Results showed that with the initial pH of 11.0, reaction time of 10min, and the additional ratio of precipitants being Mg:N:P＝1.0:1.0:1.0, over 90% NH3-N removal efficiency was achieved which would significantly facilitate the subsequent biological treatment process.

Research on Removal Effects of Pollutants by the (A/O)<sub>4</sub> SBR Process

The staged SBR is the process that divides aeration and sedimentation process of conventional SBR into several stages in time, and operates under the conditions of different stages of anaerobic/oxic/anoxic alternation. The experiment mainly discussed the five-stage SBR with useful volume of 12 L for nitrogen and phosphorous removal of synthetic municipal wastewater in the temperature ranges of 15~30°C. Tests revealed that under the condition of hydraulic retention time (HRT) is 8 hours and sludge retention time (SRT) is 15 day, the removal efficiency of COD, NH3-N, TN and TP can reach to 88.9%, 99.61%, 78.9% and 94.21%. The quality of effluent water is good, and don’t need to add Carbon Source through the experiment.

Treatment Effect of Coking Wastewater Using Three-Phase Biological Fluid-Bed with New Ultrastructure Biological Carriers Based on Properties of Biological Materials

The degradation of COD and ammonia nitrogen (NH3-N) in coking wastewater was researched using the new ultrastructure biological carriers in three-phase aerobic biological fluid-bed. The results show that the optimum conditions of the new biological carriers are as follows: HRT of 20 h, neutrality skew alkaline pH (about 7.5) and dissolved oxygen (DO) of 2~5mg/L. Under the optimum conditions, the removal efficiency of COD and NH3-N can reach 82% and 87%, respectively, when the influent concentration of COD and NH3-N is about 3000 mg/L and 60mg/L. At the same time, comparison with the activated sludge process and common biological ceramisite carriers, it is found that the most excellent treatment effect and the strongest resistance to impact are obtained under the condition of the shortest HRT in this new ultrastructure biological carriers reactor, and the effluent of two-stage reactors in series can reach the first national discharge standard, which will has a wide application prospect.

세라믹 담체에 적용된 해양박테리아 4종의 저농도 질소-인 제거

세라믹담체에 적용한 4종의 해양박테리아 (Aeromonas hydrophila, Chryseomonas indologenes, Pseudomonas diminuta, Vibrio parahaemolyticus)의 저농도 질소 인 제거 효율의 변화를 분석하였다. 해양박테리아는 광양만에서 분리 동정하였다. 담체에 적용한 4종의 해양박테리아 모두 대조군에 보다 약 3배 정도의 성장률이 증가하였으며, 암모니아서 질소 제거효율도 30% 이상 증가하였다. 질산성 질소의 제거 효율은 A. hydrophila 균주가 가장 높았으며, 인의 제거는 P. diminuta 균주가 가장 높은 것으로 나타났다. 본 연구의 결과는 세라믹담체는 질소-인 제거 효율 증진에 좋은 재료이며, 분리된 해양박테리아는 현장의 저농도 질소-인 조절에 유용할 수 있음을 보여준다. 【Changes of low concentrated nitrogen-phosphate removal efficiency were investigated in 4 strains of marine bacteria applied to ceramic media. Marine bacteria were isolated and identified from Gwangyang bay. Growth rates and removal efficiencies of $NH_3$ -N of 4 strains of marine bacteria applied to ceramic media were increased approximately 3 fold and over 30% than control group, respectively. A. hydrophila and P. diminuta had highest ${NO_3}^-$ -N and phosphate removal efficiencies, respectively. This results showed that ceramic media is very nice material for improvement of nitrogen-phosphate removal efficiency and isolated marine bacteria may be useful to control nitrogen-phosphate at low concentration in field.】

Evaluation of Sequencing Batch Biofilm Reactor for Biological Nutrient Removal from Simulated Domestic Wastewater

A lab-scale sequencing batch biofilm reactor (SBBR) was developed to treat domestic wastewater. After one year’s operation, the results were obtained as follows: when the reaction carried out in 3 h, COD removal efficiency approached or reached the maximal value, up to 90%. The nitrification process of NH3-N needed 4 h, and NH3-N removal efficiency reached the maximal value. Moreover, according to the variation of TN , NO3--N and NO2--N concentration in the nitrification and denitrification process, when NH3-N degraded to zero or the minimal value, just two cycles ending, it means that the SBBR system completed the nitrification and denitrification process.

Study on Gravel-Less Perforated Pipe Leach Fields under Different Substrate

With hydraulic loading of 3.3cm/d, five kinds of Gravel-less perforated pipe leach field’s experimental equipment (GPPLF) filled with soil or river sand to treat rural sewage were discussed. The results indicated that the optimal combination's average removal efficiencies of COD, turbidity, TP, NH3-N, and TN were 82.4%, 94.2%, 74.1%, 98.4%, 55.1% respectively. And average effluent COD, turbidity, TP, NH3-N, and TN were 17.3 mg/L, 3.9 NTU, 0.55 mg/L, 0.36 mg/L, 12.1 mg/L correspondingly. They could reach the requirement of the first degree discharge standards in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002). And contrasted with conventional perforated pipe leach fields, the removal efficiencies of COD, turbidity, TP, NH3-N, and TN were increased 1.4%, 5.1%, 22.1%, 61.8%, 15.1% accordingly. The removal mechanism analysis of NH3-N and TN revealed that the low C/N ratio was probably the most important factor for the low removal of TN.

Comparison of Luffa Cylindrical Sponge and Plastic Sponge as Carriers in Sequencing Batch Biofilm Reactor for Sewage Treatment

Luffa cylindrical sponge and plastic sponge were used as carriers in sequencing batch biofilm reactor (SBBR) for sewage treatment in this paper. The removals of suspended solid (SS), chemical oxygen demand (COD) and NH3-N in sewage were studied. The average removal efficiencies of SS, COD and NH3-N with luffa cylindrical sponge were 96%, 89% and 90%, respectively, while these with plastic sponge were 94%, 83% and 80%, respectively. As a natural, cheap and environment friendly biocarrier, luffa cylindrical sponge was easy to get a biofilm with enriched microbes during the first few days of sewage treatment. It was much more suitable as a carrier than the plastic sponge for SBBR.

Biological Nutrient Removal from Simulated Domestic Wastewater in Sequencing Batch Biofilm Reactor

A lab-scale sequencing batch biofilm reactor (SBBR) was developed to treat domestic wastewater. After one year’s operation, the results were obtained as follows: when the reaction carried out in 3 h, COD removal efficiency approached or reached the maximal value, up to 90%. The nitrification process of NH3-N needed 4 h, and NH3-N removal efficiency reached the maximal value. Moreover, according to the variation of TN , NO3--N and NO2--N concentration in the nitrification and denitrification process, when NH3-N degraded to zero or the minimal value, just two cycles ending, it means that the SBBR system completed the nitrification and denitrification process.

Performance evaluation of a granular activated carbon-sequencing batch biofilm reactor pilot plant system used in treating real wastewater from recycled paper industry

A pilot scale granular activated carbon-sequencing batch biofilm reactor with a capacity of 2.2 m3 was operated for over three months to evaluate its performance treating real recycled paper industry wastewater under different operational conditions. In this study, dissolved air floatation (DAF) and clarifier effluents were used as influent sources of the pilot plant. During the course of the study, the reactor was able to biodegrade the contaminants in the incoming recycled paper mill wastewater in terms of chemical oxygen demand (COD), adsorbable organic halides (AOX; specifically 2,4-dichlorophenol (2,4-DCP)) and ammoniacal nitrogen (NH3-N) removal efficiencies at varying hydraulic retention times (HRTs) of 1–3 days, aeration rates (ARs) of 2.1–3.4 m3/min and influent feed concentration of 40–950 mg COD/l. Percentages of COD, 2,4-DCP and NH3-N removals increased with increasing HRT, resulting in more than 90% COD, 2,4-DCP and NH3-N removals at HRT values above two days. Degradation of COD, 2,4-DCP and NH3-N were seriously affected by variation of ARs, which resulted in significant decrease of COD, 2,4-DCP and NH3-N removals by decreasing ARs from 3.4 m3/min to 2.1 m3/min, varying in the ranges of 24–80%, 6–96% and 5–42%, respectively. In comparison to the clarifier effluent, the treatment performance of DAF effluent, containing high COD concentration, resulted in a higher COD removal of 82%. The use of diluted DAF effluent did not improve significantly the COD removal. Higher NH3-N removal efficiency of almost 100% was observed during operation after maintenance shutdown compared to normal operation, even at the same HRT of one day due to the higher dissolved oxygen concentrations (1–7 mg/l), while no significant difference in COD removal efficiency was observed.

Removal of polycyclic aromatic hydrocarbons and phenols from coking wastewater by simultaneously synthesized organobentonite in a one-step process

AbstractThe optimal condition for a one-step process removing organic compounds from coking wastewater by simultaneously synthesized organobentonite as a pretreatment was investigated. Results showed that sorption of organic compounds by organobentonite was positively correlated to the cation surfactant exchange on the bentonite and the octanol-water partition coefficient (Kow) of the solutes. With 0.75 g/L bentonite and 180 mg/L (60% of bentonite cation exchange capacity) cetyltrimethylammonium bromide, the removal efficiencies of the 16 polycyclic aromatic hydrocarbon (PAHs) specified by the US Environmental Protection Agency in coking wastewater except naphthalene were more than 90%, and that of benzo(a)pyrene was 99.5%. At the same time, the removal efficiencies of CODCr, NH3-N, volatile phenols, colour and turbidity were 28.6%, 13.2%, 8.9%, 55% and 84.3%, respectively, and the ratio of BOD5/CODCr increased from 0.31 to 0.41. These results indicated that the one-step process had high removal efficiency for toxic and refractory hydrophobic organic compounds, and could improve the biodegradability of the coking wastewater. Therefore it could be a promising technology for the pretreatment of toxic and refractory organic wastewater.

Degradation of organic matter from domestic wastewater with loofah sponge biofilm reactor

A laboratory-scale oxic biofilm reactor using loofah sponge as support material was carried out to study its start-up characteristics and the optimum operation parameters in removing organic matter and nitrogen from domestic wastewater. It took no more than 10 days to complete microbiological cultivation and acclimation, indicating that the natural loofah sponge was a superior support material compared with some conventional ones. The influence parameter experiments showed that the hydraulic retention time (HRT) had a significant influence on the COD and NH(3)-N removal efficiencies, the average COD and NH(3)-N removal efficiencies were 83.7 and 96.9% respectively when the temperature was 25 ± 2 °C, the influent flow rate was 0.21 L/h and the HRT was 7.5 h. The loofah sponge biofilm system had a strong tolerance to organic shock loading in the present experiment. Additionally, it was found that domestic wastewater could be preferably treated with 88.9% of COD and 98.7% of NH(3)-N removal efficiencies with the corresponding influent concentrations of 260.0 and 26.8 mg/L, respectively. The observations obtained in the present study indicated that the loofah sponge was an excellent natural support material, potentially feasible for the present system for the treatment of the decentralized domestic wastewater.

Effect of organic loading rate on organic matter and foulant characteristics in membrane bio-reactor

In this study, the influence of organic loading rate (OLR) on the performance of a membrane bio-reactor (MBR) was investigated. The MBR was operated with 6 different OLRs between 0.5 and 3.0kgCOD/m3d. The hydrodynamic parameters of the MBR were kept constant. The hydraulic retention time and sludge retention time were kept at 8h and 40d respectively. From the experimental investigation, it was found that the removal efficiency of DOC, COD and NH4-N decreased when OLRs were increased from 0.5 to 3.0kgCOD/m3d. Higher OLRs of 2.75–3.0kgCOD/m3d resulted in a higher transmembrane pressure development. The fractionation of organic matters showed more hydrophilic substances with higher OLRs. A detailed organic matter characterization of membrane foulant, soluble microbial product and extracellular polymeric substances showed that bio-polymers type substances together with humic acid and lower molecular neutral and acids were responsible for membrane fouling.

Degradation of Landfill Leachate by Combined Three-Dimensional Electrode and Electro-Fenton

Three-dimensional-electrode electro-Fenton is a newly electrochemical oxidation technology to treat landfill leachate. In contrast, the removal efficiencies of COD and color in DSA system are obviously higher than those in iron anode system and the organics can be degraded more thoroughly. Under the optimal operating conditions, the removal efficiencies of COD, NH3-N and color in landfill leachate by DSA system are up to 80.8% ,55.2% and 98.6％. Besides, the reaction mechanism of three-dimensional-electrode electro-Fenton is also discussed.

Optimum Process Parameters for the Treatment of Landfill Leachate Using Powdered Activated Carbon Augmented Sequencing Batch Reactor (SBR) Technology

The sequencing batch reactor (SBR) process was used for the treatment of raw landfill leachate. Optimum preliminary parameters of leachate/activated sludge ratio, powdered activated carbon (PAC) dosage, and settling time were studied. Optimum obtained parameters (mixing ratio of 10%, PAC dosage of 10 g/L, and settling time of 1.5 h) were applied on two types of SBRs, namely, non-powdered and powdered activated carbon (NPAC and PAC, respectively). Consequently, the effect of factors, the aeration rate and contact time, on both NPAC and PAC reactors were studied. Response surface methodology was used for the design, analysis, and optimization of the experiments. Removal efficiencies of ammonia (NH3-N), color, chemical oxygen demand (COD), total dissolved salts (TDS), and sludge volume index (SVI) were measured for 13 experiments. Based on the obtained results, the optimum aeration rate and contact time for both NPAC and PAC reactors were 2 and 1 L/min and 5.56 and 5.5 h, respectively. Better performance (in terms of NH3-N, color, COD, and TDS removal efficiencies and SVI values) was exhibited by PAC reactors rather than NPAC.