Effluent NH4 Research Articles

Research on the Start-Up of Anaerobic Ammonia Oxidation and the Influence Factors Experiment

Experiment studies the startup of Anammox and the effect of pH and temperature on the denitrification performance of Anammox. We take the UASB reactor for Anammox startup experimental study, and study the removal of NH4+-N and NO2--N under different temperature and pH. Controlling the influent NH4+-N/NO2--N concentration ratio is 1:1.32, the initial concentration of NH4+-N is 50 mg/L, then increase NH4+-N concentration with gradient of 50 mg/L.We detect the influent and effluent NH4+-N and NO2--N and effluent NO3--N concentration .We also Control the temperature (20°C~40°C) and the pH (6.0~9.0) to study the influencing factors. The optimum temperature is 30°C, the removal rate can reach more than 80%, and the optimum pH is 8, the NH4+-N and NO2--N highest removal rate is 82.92% and 87.59%. The effect of the Anammox reaction can be efficient promotion of denitrification and provides theory basis, which provides reference for engineering application on actual conditions.

A Pilot-Scale Study on Start-Up and Operation of Biofilter with Composite Media

According to the characteristic of high ammonia nitrogen concentration of Huaihe River in winter, a pilot-scale test was studied in this paper. This paper compared the start-up and operation performance of zeolite biofilter, quartz sand + activated carbon biofilter and zeolite + activated carbon composite biofilter in lower temperature. The results show that three kinds of biofilters for NH4+-N have high remove effects. Average removal rate of zeolite biofilter, quartz sand + activated carbon biofilter, zeolite + activated carbon composite biofilter for NH4+-N were 73%,64% and 78% and effluent NH4+-N concentration were 0.31mg/L,0.24mg/L,0.21mg/L. Average CODMn removal rate of three kinds of biofilters were 5%,13% and 28%. Zeolite + activated carbon composite biofilter does not exist to NO2-N accumulation phenomenon and showed good ability to start-up and running.

Adaptability of wastewater wetland models in estimating nutrient removal in a stormwater wetland on dry days

ABSTRACT Several types of nutrient removal models, which were developed for wastewater wetlands, were applied to the data collected from a wetland treating stormwater runoff from extensive cow feeding area. First-order and regression equations were used and calibrated to estimate the removal of total phosphorus (TP), ammonium (NH4–N), total kjeldahl nitrogen (TKN), and total nitrogen (TN). To evaluate the performance of the models, the coefficient of determination (R 2), relative root mean square error (RRMSE), and model efficiency (ME), were determined. The first-order models developed produced a good prediction of the effluent TP concentration with R 2 = 0.79, RRMSE = 0.23, and ME = 0.66. On the other hand, the regression models produced very good predictions of effluent NH4–N, TKN, and TN concentrations with R 2 > 0.70, RRMSE 0.70. Therefore, the models for wastewater wetlands can be used to estimate the nutrient removal in stormwater wetlands during dry days. The removal of nutrients ...

Evaluation of rule-based control strategies according to process state diagnosis in A2/O process

In this study, rule-based control strategies were proposed according to the result of the process state diagnosis. Multivariate statistical techniques were used to derive the diagnosis results that included comprehensive information for the current process state. Based on the diagnosis result, the quantitative control setpoint could be calculated by using the optimized mathematical model. The developed process diagnosis procedure and the control strategies were applied in a pilot-scale A2/O (anaerobic/anoxic/oxic) process. The target variables in the proposed rule-based control strategies according to the process state diagnosis were the effluent NH4–N and NOX–N components. From the application of these rule-based control strategies according to the process state diagnosis, the percentages of groups 3 and 4, which were considered the abnormal process state, were decreased by about 53.8% compared to the no-control case. In addition, the maintenance interval of the control action ranged from 4h to 25h. Effluent NH4–N and NOX–N concentrations lower than the target values were maintained by applying the proposed rule-based control strategies according to the process state diagnosis. Moreover, frequent changes of the process operating state were minimized and the electrical equipment load was reduced.

Improving the Performance of Membrane Bioreactors by Adding a Metabolic Uncoupler, 4-Nitrophenol

Effects of 4-nitrophenol (4NP) on the overall performance of membrane bioreactors (MBRs) were investigated in two bench-scale submerged MBRs. Positive impacts of 4NP on activated sludge production and membrane fouling were demonstrated over 45 days of stable operational period. After addition of 4-nitrophenol, the sludge production could be reduced effectively, but only a slight reduction in chemical oxygen demand removal was obtained. The effluent NH4(+)-N concentrations were almost the same in two MBRs. The transmembrane pressures (TMPs) and resistance R increased with increasing mixed liquor suspended solid concentration at each MBR. The average daily TMP increase rates in the control MBR reactor remained at about 0.23 kPa day(-1) and dropped to about 0.12 kPa day(-1) in the 4NP-MBR. Compared with the control MBR, a wider dispersion and lower peak of floc size, a lower zeta potential, and a lower extracellular polymeric substance concentration were observed in the 4NP-MBR.

Analysis on the Start-up of Campus Sewage Treatment with 3-Stage Biological Aerated Filter

In this study, the alternating 3-stage biological aerated filter system with the brush as the filler was proposed for campus sewage treatment and the biofilm formation process was researched. Adopting the four-stage inoculated biofilm formation method, the treatment effects of the 3 filter columns respectively lasted 23d, 20d, 23d to reach stable. After the attached biofilm grew steadily, the effluent COD concentration was between 45 mg/L and 95 mg/L, and the removal efficiency was 77%~85%. The effluent NH4+-N concentration of 1st and 3rd filter columns was 11~25 mg/L, and the removal efficiency was 47%~67%; while the effluent NH4+-N concentration of 2nd filter column was 8 ~19 mg/L, the removal efficiency was 64%~ 78%.

A Modified Oxidation Ditch with Additional Internal Anoxic Zones for Enhanced Biological Nutrient Removal

A novel modified pilot scale anaerobic oxidation ditch with additional internal anoxic zones was operated experimentally, aiming to study the improvement of biological nitrogen and phosphorus removal and the effect of enhanced denitrifying phosphorus removal in the process. Under all experimental conditions, the anaerobic-oxidation ditch with additional internal anoxic zones and an internal recycle ratio of 200% had the highest nutrient removal efficiency. The effluent NH+4-N, total nitrogen (TN), PO3−4-P and total phosphorus (TP) contents were 1.2 mgL−1, 13 mgL−1, 0.3 mgL−1 and 0.4 mgL−1, respectively, all met the discharge standards in China. The TN and TP removal efficiencies were remarkably improved from 37% and 50% to 65% and 88% with the presence of additional internal anoxic zones and internal recycle ratio of 200%. The results indicated that additional internal anoxic zones can optimize the utilization of available carbon source from the anaerobic outflow for denitrification. It was also found that phosphorus removal via the denitrification process was stimulated in the additional internal anoxic zones, which was beneficial for biological nitrogen and phosphorus removal when treating wastewater with a limited carbon source. However, an excess internal recycle would cause nitrite to accumulate in the system. This seems to be harmful to biological phosphorus removal.

Pilot-scale verification of efficient nitrifier backseeding in a combined activated sludge-biofilm system

Purpose of the paper is to experimentally verify that a downstream nitrifying fixed-film reactor may effectively backseed an activated sludge (AS) system. The experiment was carried out at the Southpest Wastewater Treatment Plant in Budapest, Hungary, with two pilot-scale AS systems connected directly to the preclarified influent and to the stream recirculated from the nitrifying fixed-film reactor of the full-scale plant ensuring both the nitrate and the backwashed biomass recirculation. Effluent NH 4 -N level dropped down to near zero in the experimental systems whereas no significant nitrification occurred in the fullscale plant being operated at lower aeration intensity. Simulation model developed for describing the combined system supported that backseeding was the cause of the high nitrification efficiency having been limited by inadequate oxygen supply in the full scale system.

The Effect of Temperature on Performance of Powder Activated Carbon-I Membrane Biological Reactor (PAC-IMBR)

Under the unique long-time low temperature conditions (average 8°C) of the northern winter in China, the effects of temperature on water quality and the performance of Powder activated carbon-I Membrane biological reactor (PAC-IMBR) were studied and demonstrated quantitatively by the NH4+-N value, chemical oxygen demand (CODCr) and transmembrane pressure (TMP). The results showed that the supernatant NH4+-N decrease from 1.20 mg·L-1 to 0.81 mg·L-1 with the temperature rising from 8°C to 20°C, while 30.8 mg·L-1 to 23.1 mg·L-1 for the CODCr. However, the temperature rising have no marked influence on the effluent NH4+-N and CODCr due to the filtration of membrane. TMP was measured to characterize membrane fouling and it is clear that the TMP and its increasing rate descend with the temperature rising, which demonstrates that the raising temperature is advantageous to prolong the cycle of PAC-IMRB and alleviate the membrane fouling.

Evaluation of model-based control strategy based on generated setpoint schedules for NH4–N removal in a pilot-scale A2/O process

This paper proposes a model-based control strategy that can predict the influent and effluent as well as control the effluent water quality in the A2/O (Anaerobic/Anoxic/Oxic) process for 1day in advance. In the model-based control strategy, ANN (Artificial neural network) and modified ASM3+Bio-P model were used to predict the influent and effluent for 1day in advance, respectively. When the predicted effluent NH4–N concentration was higher than the target value, the optimal setpoint schedules of the DO (Dissolved oxygen) could be deduced using a scenario simulation. The scenario simulation was carried out to obtain DO setpoint schedules to reach the effluent NH4–N concentration under the target value. The deduced optimal setpoint schedules were used to control the operation of the process for the next day. The results of model prediction showed that the behavior of the influent and effluent could be predicted successfully. The proposed model-based control strategy was tested in a pilot-scale A2/O process for 2weeks, which confirmed that the effluent NH4–N concentration could be maintained steadily lower than the target value of 5mg/L. The air flow rate during control period was increased by 9% of that during without control period. On the other hand, their corresponding average effluent NH4–N concentrations were 4.42 and 13.89mg/L, respectively, which highlight the significant effect of this control strategy with only a slight increase in air flow rate. These results show that the developed model-based control strategy can be used successfully in the A2/O process and possibly other processes.

A Pilot-Scale Experimental Research on Biological Nitrogen Removal in a Modified SBR

A pilot-scale modified SBR process was investigated to treat urban wastewater. The average NH4+-N efficiency removal was 98 %. The average TN removal efficiency was 52 %. The average effluent NH4+-N was 0.34 mg/L. The average effluent TN was 12 mg/L. The average effluent phosphorus was 0.75 mg/L. The average effluent COD was 35 mg/L. The result showed that the ratio of influent NH4+-N /TN was equal approximately to TN removal efficiency. The TN removal ratio was decided by the influent NH4+-N. The long anaerobic time was benefit to the nitrogen removal. The optimal anaerobic time should be set at 1 hour.

A Pilot-Scale Experimental Research on Biological Phosphorus Removal in a Modified SBR Treating Urban Wastewater

A pilot-scale modified SBR process was used to treat urban wastewater. The average NH4+-N efficiency removal was 98 %. The average TN removal efficiency was 52 %. The average TP removal efficiency was 85 %. The average COD removal efficiency was 85 %. The average effluent NH4+-N was 0.34 mg/L. The average effluent TN was 12 mg/L. The average effluent phosphorus was 0.75 mg/L. The average effluent COD was 35 mg/L. The result shows that the increase of 100 mg/L MLSS concentrations by proliferation or decrease of 100 mg/L MLSS concentrations by discharging residual sludge can remove 1 mg/L total phosphorus from wastewater. The faster the MLSS increases, the higher efficiency the phosphorus removal is achieved. When MLSS is fluctuating or decreasing, the phosphorus removal would be worse than MLSS increase. When MLSS increases 500 mg/L everyday, phosphorus removal efficiency would be very high; the average phosphorus removal efficiency would be higher than 90 % in the most urban wastewater treatment plant.

Application of using surface constructed wetland for removal of chemical oxygen demand and ammonium in polluted river water

Abstract River water was mostly polluted in northern China in the past decades and the major contaminants were organic matter and ammonia. In this study the performance of the pilot-scale and full-scale surface constructed wetlands for removing COD (chemical oxygen demand) and ammonium from polluted river water was evaluated. Results showed that the effluent COD and NH4 +-N concentrations in the pilot scale wetland systems were 10.72–19.34 mg l−1 and 0.18–0.90 mg l−1, respectively, which met Grade-III (COD 20 mg l−1, NH4 +-N 1 mg l−1) of national surface water standards in China. The maximal COD and NH4 +-N removal efficiency was 96.18% and 99.78%. COD and NH4 +-N removal in spring and summer were better than that in fall and winter based on the k–C∗ model. Combined with research results of the two-year full-scale study, it indicated that the surface wetland system was a promising technology for treating polluted river water to meet the requirement of Grade-III water quality in northern China.

Study on Oil Refining Wastewater Treatment by Membrane Bioreactor with A/O Process

In this experimentation an A/O submerged membrane bioreactor was designed to study the treatment of oil-refining wastewater. The result show that the average effluent COD was below 18 mg/L, the removal rate of COD was over 97% and the removal rate was stable; the removal rate of NH4+-N was influenced by PH value, the average effluent NH4+-N was less than 0.97 mg/L and the average removal rate was over 98%; the average effluent oil was below 5mg/L and removal rate was over 96%; effluent phenol was less than 0.12mg/L and the removal rate was nearly 100%.

Performance of an ultra-compact biofilm reactor treating domestic and synthetic wastewaters

The performance of an ultra-compact biofilm reactor (UCBR) treating domestic wastewater (DWW) collected from a local water reclamation plant; and gradually shifting to a mono-type carbon source synthetic wastewater (SWW) combined with DDW (CWW) and finally SWW; was investigated in this study. The total COD concentrations of influent DWW and CWW/SWW were 413.6 ± 80.8 mg/L and 454.9 ± 51.3 mg/L, respectively. The UCBR was able to achieve average total COD removal efficiencies of 70 ± 10% and 80 ± 4% for DWW and SWW respectively. The total COD concentrations of the effluent of DWW and CWW/SWW were 122.5 ± 44.4 mg/L and 89.7 ± 10.3 mg/L, respectively. These observations suggested that heterotrophs in the UCBR system were able to better assimilate and remove carbon of mono-type SWW compared to diverse carbon sources such as DWW; although the influent soluble COD concentrations of the SWW were higher than those of the DWW. However, the effluent NH(4)(+)-N concentrations for both types of wastewater were rather similar, <3.0 mg/L; although the influent NH(4)(+)-N concentrations of the DWW were 1.5 times those of the SWW.

Nutrient Removal from Polluted River Water by Using Vertical and Horizontal Subsurface Flow Constructed Wetlands

The main purpose of this study was to treat organic pollutants, nitrogen and phosphorus in polluted river water by the use of constructed wetland (CW) systems. A laboratory experiment research was conducted on subsurface flow constructed wetland systems operated in vertical flow (VF) and horizontal flow (HF) mode. The systems were unplanted and hydraulic retention times were identically 2.7 days. The average removal efficiencies for HFCW and VFCW were NH+ 4-N 64.9% and 75.2%, NO- 3-N 92.3% and 40.1%, COD 97.5% and 90.1%, TP 94.6% and 96.2%, respectively. The removal of NH+ 4-N and NO- 3-N in the different CW units were in order of VFCW (drained) &gt; VFCW (flooded) &gt; HFCW and HFCW &gt; VFCW (flooded) &gt; VFCW (drained), respectively. When the water level in the VFCW was changed, an obvious fluctuation of the effluent NH+ 4-N and NO- 3-N concentrations was observed.

The Performance of a Three Phase Fluidized Bed Biofilm Reactor in Treatment of Sugar Factory Wastewater

The performance of a three phase fluidized bed biofilm reactor used to treat cane sugar wastewater has been investigated. Experimental results showed that, the continuous bioprocess treated the real wastewater of sugar cane factories under the condition of maintaining the hydraulic retention time (HRT) at 3~3.5 h, the maximum removal percentage of COD and NH4–N could reach to 91.38% and 92.39% respectively, and the effluent COD and NH4–N were lower than 120 and 10 mg /L for 40 days, which had achieved the national primary discharge standard of PR China. And when the organic loading rate (OLR) was increased from 2.3 kgCOD/m3•d to 5.1kgCOD/m3•d, the reactor can achieve the treatment without affecting its performance, and the reactor had high operation flexibility and the ability to resist shock loading.

Improving Nitrogen Removal in Two Modified Decentralized Wastewater Systems

Efficient nutrient removal in decentralized wastewater treatment systems is a challenging task. To improve the removal of organic matter and nitrogen from wastewater, two types of bioreactors using membrane-aerated biofilm reactor (MABR) and microbial fuel cell (MFC) techniques were evaluated. During more than 250 days of continuous-flow reactor operation, both reactors showed consistently high chemical oxygen demand removal (>86%). At an influent ammonium-nitrogen (NH4(+)-N) concentration of 30 mg N/L, the average effluent NH4(+)-N concentrations were 6.2 and 0.5 mg N/L for the MABR and MFC reactor, respectively, while the effluent nitrate-nitrogen (NO3(-)-N) concentrations were 5.4 mg/ L in the MABR and 19.2 mg/L in the MFC-based reactor. The overall total inorganic nitrogen removal efficiencies were 64% and 36% for the MABR and MFC reactor, respectively. At the measured dissolved oxygen concentrations of 5.2 and 0.23 mg/L in the aerobic/anoxic zone of the MFC and MABR, respectively, a specific oxygen uptake rate of 0.1 g O2/g VSS-d, resulting from ammonia oxidation, was detected in the settled sludge of the MFC, while no nitrifying activity of the sludge from the MABR was detected. Molecular microbial analysis demonstrated a link between the bacterial community structure and nitrifying activity. The relatively high abundance of Nitrosomonas europaea was associated with its detectable nitrification activity in the settled sludge of the MFC. The results suggest that MABR and MFC techniques have the potential to improve organic and nitrogen removal in decentralized wastewater systems.

Oxic-settling-anoxic (OSA) process combined with 3,3′,4′,5-tetrachlorosalicylanilide (TCS) to reduce excess sludge production in the activated sludge system

The potential of oxic-settling-anoxic (OSA) process with addition of 3,3′,4′,5-tetrachlorosalicylanilide (TCS) to reduce excess sludge production was investigated. TCS was dosed into aeration tank with 0.05, 0.10 and 0.15 g every other day in three lab-scale OSA processes, respectively to form the TCS and OSA combined processes. The OSA and TCS combined processes reduced sludge yield by 21–56% under the same sludge retention time (6.75 h) in sludge anoxic holding tank. Substrate removal capability, effluent NH 3-N concentrations and total phosphorus removal rates were not adversely affected by the presence of TCS or insertion of sludge anoxic holding tank, but total nitrogen removal rates only decreased significantly in the system with addition of 0.15 g TCS during the 60-day continuous operation. The settleability of sludge in four systems was qualitatively comparable and not significantly different. Microscopic examination and the banding patterns of DGGE profiles demonstrated that microbial population changed after TCS addition and insertion of anoxic sludge holding tank. The results suggest that TCS and OSA combined process is effective in reducing sludge yield, and process performance as well as sludge settleability are not significantly affected by introduction of the chemical uncoupler. The results imply that reduction of excess sludge production is due to uncoupled metabolism at low TCS dosage, but microbial death at high TCS dosage.

Modeling a bench-scale alternating aerobic/anoxic activated sludge system for nitrogen removal using a modified ASM1

The Activated Sludge Model No. 1 (ASM1), developed by The International Association of Water Pollution Research and Control, was applied to model dynamics of NH4 +, and NO3 − in a bench scale alternating aerobic-anoxic (AAA) activated sludge system for nitrogen removal. The model was modified by eliminating inert soluble COD (SI) and inert particulate COD (XI) from the model's state variables as these two variables are not involved in any biological reaction and are not readily measurable with conventional routine COD analysis. It was assumed that the soluble COD and particulate COD of wastewater represent readily biodegradable COD (SS) and slowly biodegradable (XS) in the model, respectively. In addition, alkalinity was also removed from the model, since alkalinity of an AAA system remains stable due to the cyclic modes of the system. Even with the elimination of the three state variables and the assumption made, the model could reasonably predict the NH4 + and NO3 − dynamics of the AAA system, and effluent NH4 + and NO3 − concentrations with adjustment of only a few kinetic parameters. Compared to the original ASM1, it is expected that the modified ASM1 presented in this study can be more easily utilized by engineers in designing or operating an AAA system in practice, since it requires simple characterization of wastewater COD.