Effects of the DO of Nitrification Return Flow on the Nitrogen Removal of A/A-MBR Combined Process

2012 ◽  
Vol 174-177 ◽  
pp. 58-63 ◽  
Author(s):  
Xiao Ying Zheng ◽  
Wei Chen ◽  
Ji Li ◽  
Yu Jie He ◽  
Xi Huang ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Membrane Fouling ◽  
Municipal Wastewater ◽  
Removal Rate ◽  
Treatment Plant ◽  
Denitrification Rate ◽  
Effective Control ◽  
Return Flow ◽  
Stable Operation ◽  
Combined Process

In this study, the traditional A/A/O process was combined with MBR to create the A/A-MBR combined process. A 2.0 m3/h pilot scale study on the combined process was carried out. The influence mechanism of dissolved oxygen (DO) in the return flow on the A/A-MBR combined process was analyzed and the suitable dissolved oxygen concentration in MBR was further optimized. The results show that the combined process has the characteristics of rapid start and stable operation. Its COD, NH4+-N, TN and TP removals were 82.1%~92.4%, 93.0~98.3%, 48.4~70.7% and 93.8~97.9%, respectively. The return flow with high concentration of DO in MBR seriously affected the denitrification rate. The DO concentration of return flow increased gradually from 2.0 mg/L to 5.0 mg/L, the denitrification rate continuously decreased, the denitrification rate in the first stage decreased from 2.52 mg NO3--N/(gVSS•h) to 0.34mg NO3--N/(gVSS•h). When the DO of nitrification return liquid ascended to 5 mg/L, the denitrification ability of activated sludge was severely inhibited, and its denitrification activity was even lost. DO were controlled between 4.0±0.5 mg/L by adjusting the aeration rate in the MBR, effluent TN could be stably maintained between 10.82-13.94 mg/L with 62.6% average removal rate. The effluent COD, NH4+-N, TN and TP stably qualified to t criteria of the first level A of China’ s "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant" (GB18918-2002). If the effective control of membrane fouling could be ensured, the DO in the MBR was controlled as much as possible fewer than 4.0 mg/L. This could decrease the inhibition of denitrification by high DO from the return flow and insure that effluent TN achieved the discharge standard.

Control of Bulking in an Extended Aeration Sewage Treatment Plant

1972 ◽  
Vol 7 (1) ◽  
pp. 13-20
Author(s):  
D.D.P. Cane ◽  
G.J. Farguhar
Keyword(s):  
Dissolved Oxygen ◽  
Control Measure ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Effective Control ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Mixed Liquor ◽  
Air Supply

Abstract A case of filamentous activated sludge bulking was investigated at an extended aeration plant treating wastes from a highway service centre. The purpose of the study was to find an effective control measure for the bulking and, if possible, to determine the cause of the bulking condition. Experiments were conducted to determine the effects upon bulking of: (a) a controlled copper dosage to the mixed liquor, (b) variations in the organic loading rate, and (c) maintenance of high and low dissolved oxygen concentrations in the mixed liquor. The microorganism responsible for the bulking condition was tentatively identified as Sphaerotilus natans. Extensive growths of these bacteria occurred in the sludge when the mixed liquor dissolved oxygen concentration dropped below 0.5 mg/1. Such dissolved oxygen levels had frequently occurred at this plant due to the use of timed aeration cycles and the use of insufficient air supply during peak loading periods. Variations in organic loading rates were found to have no adverse effect on sludge settleability. When bulking was slight, the condition could be improved by increasing the dissolved oxygen level to 1.5 mg/1, or more. The rate at which the filamentous growths could be eliminated from a highly filamentous sludge by increased aeration was very slow, but could be greatly increased by the simultaneous feeding of copper to the mixed liquor at a dosage rate of 1.0 mg/1, based on the raw sewage flows.

scholarly journals Assessment of Microplastics in a Municipal Wastewater Treatment Plant with Tertiary Treatment: Removal Efficiencies and Loading per Day into the Environment

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1339
Author(s):  
Javier Bayo ◽  
Sonia Olmos ◽  
Joaquín López-Castellanos
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Municipal Wastewater ◽  
Removal Rate ◽  
Treatment Plant ◽  
Source Control ◽  
Municipal Wastewater Treatment ◽  
Tertiary Treatment ◽  
Stable Performance ◽  
Wastewater Samples

This study investigates the removal of microplastics from wastewater in an urban wastewater treatment plant located in Southeast Spain, including an oxidation ditch, rapid sand filtration, and ultraviolet disinfection. A total of 146.73 L of wastewater samples from influent and effluent were processed, following a density separation methodology, visual classification under a stereomicroscope, and FTIR analysis for polymer identification. Microplastics proved to be 72.41% of total microparticles collected, with a global removal rate of 64.26% after the tertiary treatment and within the average retention for European WWTPs. Three different shapes were identified: i.e., microfiber (79.65%), film (11.26%), and fragment (9.09%), without the identification of microbeads despite the proximity to a plastic compounding factory. Fibers were less efficiently removed (56.16%) than particulate microplastics (90.03%), suggesting that tertiary treatments clearly discriminate between forms, and reporting a daily emission of 1.6 × 107 microplastics to the environment. Year variability in microplastic burden was cushioned at the effluent, reporting a stable performance of the sewage plant. Eight different polymer families were identified, LDPE film being the most abundant form, with 10 different colors and sizes mainly between 1–2 mm. Future efforts should be dedicated to source control, plastic waste management, improvement of legislation, and specific microplastic-targeted treatment units, especially for microfiber removal.

Enhanced Performance of Ultrafiltration Membrane with Powdered Zeolite Addition for Secondary Effluent Treatment

2013 ◽  
Vol 838-841 ◽  
pp. 2712-2716
Author(s):  
Yong Tu ◽  
Yong Gang Bai ◽  
Yong Chen ◽  
Wei Jing Liu ◽  
Jun Xu ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Fluorescence Spectra ◽  
Municipal Wastewater ◽  
Three Dimensional ◽  
Treatment Plant ◽  
Ultrafiltration Membrane ◽  
Effluent Treatment ◽  
Secondary Effluent ◽  
Municipal Wastewater Treatment ◽  
Sem Images

The research on ultrafiltration membrane assisted by powdered zeolite for the treatment of secondary effluent from a municipal wastewater treatment plant was studied. The results show that membrane fouling rate is reduced by pre-coating the ultrafiltration membrane with powdered zeolite, and the treatment performance of secondary effluent is enhanced. UV-vis, three-dimensional excitation emission matrix (3D-EEM) fluorescence spectra and scanning electron microscopy (SEM) images for ultrafiltration were also discussed.

scholarly journals Upflow packed bed Anammox reactor used in two-stage deammonification of sludge digester effluent

2018 ◽  
Vol 78 (9) ◽  
pp. 1843-1851 ◽  
Author(s):  
İ. Çelen-Erdem ◽  
E. S. Kurt ◽  
B. Bozçelik ◽  
B. Çallı
Keyword(s):  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Municipal Wastewater ◽  
Removal Rate ◽  
Treatment Plant ◽  
Packed Bed ◽  
Municipal Wastewater Treatment ◽  
Two Stage ◽  
N Removal ◽  
Total Nitrogen Removal

Abstract The sludge digester effluent taken from a full scale municipal wastewater treatment plant (WWTP) in Istanbul, Turkey, was successfully deammonified using a laboratory scale two-stage partial nitritation (PN)/Anammox (A) process and a maximum nitrogen removal rate of 1.02 kg N/m3/d was achieved. In the PN reactor, 56.8 ± 4% of the influent NH4-N was oxidized to NO2-N and the effluent nitrate concentration was kept below 1 mg/L with 0.5–0.7 mg/L of dissolved oxygen and pH of 7.12 ± 12 at 24 ± 4°C. The effluent of the PN reactor was fed to an upflow packed bed Anammox reactor where high removal efficiency was achieved with NO2-N:NH4-N and NO3-N:NH4-N ratios of 1.32 ± 0.19:1 and 0.22 ± 0.10:1, respectively. The results show that NH4-N removal efficiency up to 98.7 ± 2.4% and total nitrogen removal of 87.7 ± 6.5% were achieved.

Upgrading of Florence wastewater treatment plant: co-digestion and nitrogen autotrophic removal

2005 ◽  
Vol 52 (4) ◽  
pp. 9-17 ◽  
Author(s):  
S. Caffaz ◽  
R. Canziani ◽  
C. Lubello ◽  
D. Santianni
Keyword(s):  
Nitrogen Removal ◽  
Pilot Plant ◽  
Municipal Wastewater ◽  
Biogas Production ◽  
Removal Rate ◽  
Treatment Plant ◽  
Experimental Results ◽  
Septic Tank ◽  
Technical Solution ◽  
Nitrite Production

In recent years a completely autotrophic nitrogen removal process based on Anammox biomass has been tested in a few European countries in order to treat anaerobic supernatant and to increase the COD/N ratio in municipal wastewater. This work reports experimental results on a possible technical solution to upgrade the S. Colombano treatment plant which treats wastewater from the Florentine urban area. The idea is to use 50% of the volume of the anaerobic digester in order to treat external sewage sludge (as septic tank sludge) together with waste activated sludge and to treat the resulting effluent on a SHARON-ANAMMOX process in order to remove nitrogen from the anaerobic supernatant. Anaerobic co-digestion, tested in a 200 L pilot plant, enables low cost treatment of septic tank sludge and increases biogas production; however, it also increases the nitrogen load re-circulated to the WWTP, where nitrogen removal efficiency is already low (<50%), due to the low COD/N ratio, which limits predenitrification efficiency. Experimental results from a SHARON process tested in a lab-scale pilot plant show that nitrite oxidising bacteria are washed-out and steady nitrite production can be achieved at retention times in the range 1–1.5 days, at 35 °C. In a lab-scale SBR reactor, coupled with a nitration bioreactor, maximum specific nitrogen removal rate under nitrite-limiting conditions (with doubling time equal to about 26 days at 35 °C) was equal to 0.22 kgN/kgSSV/d, about 44 times the rate measured in inoculum Anammox sludge. Finally, a cost analysis of the proposed upgrade is reported.

scholarly journals Enhancing Nitrate Removal from Waters with Low Organic Carbon Concentration Using a Bioelectrochemical System—A Pilot-Scale Study

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 516 ◽  
Author(s):  
Rauno Lust ◽  
Jaak Nerut ◽  
Kuno Kasak ◽  
Ülo Mander
Keyword(s):  
Organic Carbon ◽  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Power Efficiency ◽  
Municipal Wastewater ◽  
Nitrate Removal ◽  
Treatment Plant ◽  
Municipal Wastewater Treatment ◽  
Dissolved Oxygen Concentration ◽  
Organic Carbon Concentration

Assessments of groundwater aquifers made around the world show that in many cases, nitrate concentrations exceed the safe drinking water threshold. This study assessed how bioelectrochemical systems could be used to enhance nitrate removal from waters with low organic carbon concentrations. A two-chamber microbial electrosynthesis cell (MES) was constructed and operated for 45 days with inoculum that was taken from a municipal wastewater treatment plant. A study showed that MES can be used to enhance nitrate removal efficiency from 3.66% day−1 in a control reactor to 8.54% day−1 in the MES reactor, if a cathode is able to act as an electron donor for autotrophic denitrifying bacteria or there is reducing oxygen in a cathodic chamber to favor denitrification. In the MES, greenhouse gas emissions were also lower compared to the control. Nitrous oxide average fluxes were −639.59 and −9.15 µg N m−2 h−1 for the MES and control, respectively, and the average carbon dioxide fluxes were −5.28 and 43.80 mg C m−2 h−1, respectively. The current density correlated significantly with the dissolved oxygen concentration, indicating that it is essential to keep the dissolved oxygen concentration in the cathode chamber as low as possible, not only to suppress oxygen’s inhibiting effect on denitrification but also to achieve better power efficiency.

Performance of membrane bioreactor combined with pre-coagulation/sedimentation

2004 ◽  
Vol 4 (1) ◽  
pp. 143-149 ◽  
Author(s):  
T. Itonaga ◽  
Y. Watanabe
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Suspended Solids ◽  
Extracellular Polymeric Substances ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Municipal Wastewater Treatment ◽  
Term Operation ◽  
Made In

This paper deals with the performance of a hybrid membrane bioreactor (MBR) combined with pre-coagulation/sedimentation. Primary clarifier effluent in a municipal wastewater treatment plant was fed into the hybrid MBR to investigate its performance during long-term operation. Pre-coagulation/sedimentation process efficiently removed the suspended solids including organic matter and phosphorus. Comparison of the hybrid MBR and conventional MBR was made in terms of the permeate quality and membrane fouling. As the organic loading to the MBR was significantly reduced by the pre-coagulation/sedimentation, production and accumulation of extracellular polymeric substances (EPS) may be limited. Therefore, the mixed liquor viscosity in the hybrid MBR was much lower than that in the conventional MBR. These effect caused by pre-coagulation/sedimentation brought a remarkable improvement in both permeate quality and membrane permeability.

Integrated Treatment of Domestic Wastewater Using Anaerobic Filter-Constructed Wetland in Military Camps

2011 ◽  
Vol 356-360 ◽  
pp. 1331-1334
Author(s):  
Tao Lv ◽  
Wu Long Zhang ◽  
Xie Zhang ◽  
Feng Xue
Keyword(s):  
Constructed Wetland ◽  
Municipal Wastewater ◽  
Removal Rate ◽  
Treatment Plant ◽  
Domestic Wastewater ◽  
Integrated Treatment ◽  
Municipal Wastewater Treatment ◽  
Anaerobic Filter ◽  
Integrated Technique ◽  
Packing Layer

This paper studies through project cases the treatment effect of integrated technique of anaerobic filter and constructed wetland on domestic wastewater in military camps, and the method for preventing the blocking of anaerobic filter and constructed wetland packing. The results show that its average removal rate of COD, NH4+-N, TP and SS is 83.1%, 37.5%, 49.8% and 91.5% respectively, with effluent meeting the standard of Grade II in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002); as planned, two anaerobic filters, one for operation and the other laying fallow at a alternate period of 6 months, in combination of the design of spoil disposal, can effectively prevent the packing layer from being blocked; being preprocessed, anaerobic filter can effectively prevent the packing layer of constructed wetland from being blocked; in case of a certain difference in elevation, the integrated technique can achieve unpowered operation. Besides, it is easy to implement and manage at a low operational cost without professional technician, and can treat decentralized domestic wastewater, therefore, is suitable for camps.

Removal Efficiency of Environmental Endocrine Disrupting Chemicals Pollutants-Phthalate Esters in Northern WWTP

2013 ◽  
Vol 807-809 ◽  
pp. 694-698
Author(s):  
Rong Xin Huang ◽  
Zhen Xing Wang ◽  
Gang Liu ◽  
Qi Jin Luo
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Municipal Wastewater ◽  
Removal Rate ◽  
Phthalate Esters ◽  
Endocrine Disrupting Chemicals ◽  
Treatment Plant ◽  
Activated Sludge Process ◽  
Wastewater Reclamation ◽  
Conventional Activated Sludge

In order to guarantee the reliability and security of reclaiming water, research on the removal efficiency of the environmental endocrine chemicals (EDCs) --the Phthalate Esters (PAEs) in conventional secondary activated sludge and wastewater reclamation and reuse process was undergoing at Harbin wastewater treatment plant (WWTP). The wastewater samples were colleted from every unit effluent of WWTP. The results showed that contamination of EDCs were presented in municipal wastewater at Harbin and the concentrations of the four PAEs were 21.01μg/L for Di-n-butyl Phthalate (DBP); 9.63μg/L for Di-n-octyl Phthalate (DnOP); 4.56μg/L for Diethyl Phthalate (DEP); 1.96μg/L for Dimethyl Phthalate (DMP) respectively in the influent. The conventional activated sludge has good removal efficiencies performance on DMP, DEP and DBP. With the increasing of molecular weight and branch chains of PAEs contaminations, the removal rate of the four PAEs in the conventional activated sludge process decreased from 99.82%(DMP)，90.60%(DEP)，90.10%(DBP) to the only 45.13% removal rate for DnOP, which was mostly removed from primary treatment but no from secondary activated sludge process; Coagulation-air flotation plus filtration process was not a feasible way to remove PAEs from reclaiming treatment units.

scholarly journals Microcoagulation improved the performance of the UF–RO system treating the effluent from a coastal municipal wastewater treatment plant: a pilot-scale study

2021 ◽  
Author(s):  
Tong Yu ◽  
Chenlu Xu ◽  
Feng Chen ◽  
Haoshuai Yin ◽  
Hao Sun ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Membrane Fouling ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Contaminant Removal ◽  
Municipal Wastewater Treatment ◽  
Municipal Wastewater Treatment Plant ◽  
Ro Membrane

Abstract Microcoagulation has recently been considered as a promising pretreatment for an ultrafiltration (UF) process from numerous studies. To investigate the effects of microcoagulation on the performance of the UF–reverse osmosis (RO) system treating wastewater with high and fluctuant salinity, different dosages of coagulant (poly-aluminum chloride) were added prior to the UF unit in a pilot-scale UF–RO system for a 10-week period operation. Microcoagulation obviously improved the contaminant removal and cleaning efficiencies, including water backwash, chemical enhanced backwash and cleaning in place processes. Organic fouling was dominated during the initial stage of the RO membrane fouling. The microbial communities of water samples and foulant on the RO membrane were similar to those of seawater and foulant on the RO membranes from seawater RO plants. The microbial community of the foulant on the membrane was similar to that of UF permeate and RO concentrate. These results demonstrated that microcoagulation could improve the performance of the UF–RO system treating the effluent with high and fluctuant salinity from a coastal municipal wastewater treatment plant.

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