Impact of SRT on Simultaneous Nitrification and Denitrification in a Carrousel Oxidation Ditch for Sewage Treatment

2012 ◽  
Vol 550-553 ◽  
pp. 2104-2107
Author(s):  
Yi Ming Chen

The impact of SRT on simultaneous nitrification and denitrification (SND) in the Carrousel Oxidation Ditch was carried out based on pilot-scale to treat low COD/TN municipal sewage. The impact factor, sludge retention time (SRT), was investigated on the occurrence of SND. The experiment results showed that in the oxygen-deficient environment whose DO was 0.3 mg/L, R of 50%, MLSS of 4000 mg/L, the treatment efficiency achieved the best with SRT of 20 d, the COD, ammonia nitrogen, total nitrogen (TN) of effluent were lower than 32 mg/L, 5 mg/L, 13 mg/L, respectively, which was observed efficient phenomenon of SND. Overall, these results demonstrated that the Carrousel Oxidation Ditch with the occurrence of SND could have the potential to treat low C/N sewage.

Author(s):  
Izabela Major Barbosa ◽  
José Carlos Mierzwa ◽  
Ivanildo Hespanhol ◽  
Eduardo Lucas Subtil

This study evaluated the removal of nitrogen and organic matter in a membrane bioreactor system operating in a condition of simultaneous nitrification and denitrification controlled by intermittent aeration. A submerged-membrane system in a bioreactor was used in a pilot scale to treat domestic wastewater. The dissolved oxygen concentration was maintained between 0.5 and 0.8 mg L-1. The concentration of the mixed liquor suspended solids (MLSS) in the system ranged from 1 to 6 g L-1. The system efficiency was evaluated by the removal efficiency of organic matter, quantified by Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD5) and Total Organic Carbon (TOC). Nitrogen removal was assessed by quantifying Total Kjeldahl Nitrogen (TKN) and ammonia nitrogen. During the system start-up, the removal efficiencies of COD and NTK were around 90% and 80%, respectively. After the simultaneous nitrification and denitrification (SND) conditions were established, the removal efficiencies of COD and NTK were 70% and 99%, respectively. These results showed that sewage treatment with the membrane bioreactor (MBR) system, operating with simultaneous nitrification and denitrification conditions, was able to remove organic matter and promote nitrification and denitrification in a single reactor, producing a high-quality permeate.


Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2181 ◽  
Author(s):  
Gonghan Xia ◽  
Wenlai Xu ◽  
Qinglin Fang ◽  
Zishen Mou ◽  
Zhicheng Pan

In this work, the influence of graphene on nitrogen and phosphorus in a batch Chlorella reactor was studied. The impact of graphene on the removal performance of Chlorella was investigated in a home-built sewage treatment system with seven identical sequencing batch Chlorella reactors with graphene contents of 0 mg/L (T1), 0.05 mg/L (T2), 0.1 mg/L (T3), 0.2 mg/L (T4), 0.4 mg/L (T5), 0.8 mg/L (T6) and 10 mg/L (T7). The influence of graphene concentration and reaction time on the pollutant removal performance was studied. The malondialdehyde (MDA) and total superoxide dismutase (SOD) concentrations in each reactor were measured, and optical microscopy and scanning electron microscopy (SEM) characterizations were performed to determine the related mechanism. The results show that after 168 h, the total nitrogen (TN), ammonia nitrogen (AN) and total phosphorus (TP) removal rates of reactors T1–T7 become stable, and the TN, AN and TP removal rates were gradually reduced with increasing graphene concentration. At 96 h, the concentrations of both MDA and SOD in T1–T7 gradually increased as the graphene concentration increased. In optical microscopy and SEM measurements, it was found that graphene was adsorbed on the surface of Chlorella, and entered Chlorella cells, deforming and reducing Chlorella. Through the blood plate count method, we estimated an average Chlorella reduction of 16%. According to the water quality and microscopic experiments, it can be concluded that the addition of graphene causes oxidative damage to microalgae and destruction of the Chlorella cell wall and cell membrane, inhibiting the nitrogen and phosphorus removal in Chlorella reactors. This study provides theoretical and practical support for the safe use of graphene.


2021 ◽  
Vol 8 (12) ◽  
Author(s):  
Zhen-dong Zhao ◽  
Qiang Lin ◽  
Yang Zhou ◽  
Yu-hong Feng ◽  
Qi-mei Huang ◽  
...  

The development of efficient and low-cost wastewater treatment processes remains an important challenge. A microaerobic up-flow oxidation ditch (UOD) with micro-electrolysis by waterfall aeration was designed for treating real municipal wastewater. The effects of influential factors such as up-flow rate, waterfall height, reflux ratio, number of stages and iron dosing on pollutant removal were fully investigated, and the optimum conditions were obtained. The elimination efficiencies of chemical oxygen demand (COD), ammonia nitrogen (NH 4 + -N), total nitrogen (TN) and total phosphorus (TP) reached up to 84.33 ± 2.48%, 99.91 ± 0.09%, 93.63 ± 0.60% and 89.27 ± 1.40%, respectively, while the effluent concentrations of COD, NH 4 + -N, TN and TP were 20.67 ± 2.85, 0.02 ± 0.02, 1.39 ± 0.09 and 0.27 ± 0.02 mg l −1 , respectively. Phosphorous removal was achieved by iron–carbon micro-electrolysis to form an insoluble ferric phosphate precipitate. The microbial community structure indicated that carbon and nitrogen were removed via multiple mechanisms, possibly including nitrification, partial nitrification, denitrification and anammox in the UOD.


2015 ◽  
Vol 57 (42) ◽  
pp. 19609-19618
Author(s):  
Jiashun Cao ◽  
Jianming Cai ◽  
Chao Li ◽  
Zhen Zhang ◽  
Yusheng Li ◽  
...  

1994 ◽  
Vol 29 (10-11) ◽  
pp. 431-438 ◽  
Author(s):  
Y. Watanabe ◽  
D. Y. Bang ◽  
K. Itoh ◽  
K. Matsui

This paper concerns simultaneous nitrification and denitrification in a completely mixed bio-reactor with partially and fully submerged rotating biological contactors. The bio-reactor is designed to cause the nitrification and denitrification in partially and fully submerged biofilms, respectively. An experimental investigation was made into the effect of organic material and ratio of influent organic carbon to ammonia nitrogen concentrations(C/N ratio) on the efficiency of simultaneous nitrification and denitrification in the bio-reactor. Settled municipal wastewater and synthetic wastewater containing ammonia nitrogen and organic material such as acetate, ethylene-glycol, phenol and poly-vinyl-alcohol(PVA) were fed into the experimental units. A biofilm dominated by nitrifiers developed on the partially submerged contactors, while a biofilm dominated by heterotrophs developed on the fully submerged contactors. A micro-aerobic environment was formed and biological denitrification occurred in the submerged biofilm. In the municipal wastewater treatment where the influent C/N ratio was around 3.5, the maximum nitrogen removal efficiency was about 60 %. Acetate and ethlene-glycol were effectively used as the organic source of the denitrification. The ability to aerobically degrade PVA was induced by phenol. Once the bacteria inhibiting the biofilm gained the ability to degrade PVA, PVA became an effective organic source of the denitrification.


2012 ◽  
Vol 550-553 ◽  
pp. 2142-2145 ◽  
Author(s):  
Gao Shun Qiu ◽  
Ling Feng Qiu ◽  
Jian Zhang ◽  
Yi Ming Chen

This paper was based on Carrousel oxidation ditch, which was common in the urban sewage treatment plants. With the effect of SND in the oxidation ditch, it was accomplished the effective removal for nitrogen and phosphorus of urban sewage with low C/N, while adopting point-aeration and brush flow, combining with the operation parameters adjustment. Under the condition of low dissolved oxygen (DO), the phenomenon of simultaneous nitrification and denitrification was obvious in macro and micro environments. And compared with the traditional process, this process increased the proportion of organics up to 51% in the ditch, which raised utilization rate of organics. Based on this to establish the kinetics model of TN removal, it could control the concentration of TN in the effluent effectively by adjusting HRT, MLSS and other parameters in the oxidation ditch, which would provide effective theory basis for optimization and adjustment of the process


2017 ◽  
Vol 43 (3) ◽  
pp. 74-81 ◽  
Author(s):  
Bartosz Szeląg ◽  
Lidia Bartkiewicz ◽  
Jan Studziński ◽  
Krzysztof Barbusiński

AbstractThe aim of the study was to evaluate the possibility of applying different methods of data mining to model the inflow of sewage into the municipal sewage treatment plant. Prediction models were elaborated using methods of support vector machines (SVM), random forests (RF), k-nearest neighbour (k-NN) and of Kernel regression (K). Data consisted of the time series of daily rainfalls, water level measurements in the clarified sewage recipient and the wastewater inflow into the Rzeszow city plant. Results indicate that the best models with one input delayed by 1 day were obtained using the k-NN method while the worst with the K method. For the models with two input variables and one explanatory one the smallest errors were obtained if model inputs were sewage inflow and rainfall data delayed by 1 day and the best fit is provided using RF method while the worst with the K method. In the case of models with three inputs and two explanatory variables, the best results were reported for the SVM and the worst for the K method. In the most of the modelling runs the smallest prediction errors are obtained using the SVM method and the biggest ones with the K method. In the case of the simplest model with one input delayed by 1 day the best results are provided using k-NN method and by the models with two inputs in two modelling runs the RF method appeared as the best.


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