Effects of chemical oxygen demand (COD)/N ratios on pollutants removal in the subsurface wastewater infiltration systems with/without intermittent aeration

2016 ◽  
Vol 73 (11) ◽  
pp. 2662-2669 ◽  
Author(s):  
Siyu Song ◽  
Jing Pan ◽  
Shiwei Wu ◽  
Yijing Guo ◽  
Jingxiao Yu ◽  
...  
Keyword(s):  
Chemical Oxygen Demand ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Oxygen Deficiency ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Intermittent Aeration ◽  
Oxidation Reduction ◽  
The Matrix ◽  
Pollutants Removal

The matrix oxidation reduction potential level, organic pollutants and nitrogen removal performances of eight subsurface wastewater infiltration systems (SWISs) (four with intermittent aeration, four without intermittent aeration) fed with influent chemical oxygen demand (COD)/N ratio of 3, 6, 12 and 18 were investigated. Nitrification of non-aerated SWISs was poor due to oxygen deficiency while higher COD/N ratios further led to lower COD and nitrogen removal rate. Intermittent aeration achieved almost complete nitrification, which successfully created aerobic conditions in the depth of 50 cm and did not change anoxic or anaerobic conditions in the depth of 80 and 110 cm. The sufficient carbon source in high COD/N ratio influent greatly promoted denitrification in SWISs with intermittent aeration. High average removal rates of COD (95.68%), ammonia nitrogen (NH4+-N) (99.32%) and total nitrogen (TN) (89.65%) were obtained with influent COD/N ratio of 12 in aerated SWISs. The results suggest that intermittent aeration was a reliable option to achieve high nitrogen removal in SWISs, especially with high COD/N ratio wastewater.

scholarly journals In Situ Nutrient Removal from Rural Runoff by A New Type Aerobic/Anaerobic/Aerobic Water Spinach Wetlands

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1100 ◽  
Author(s):  
Ya-Wen Wang ◽  
Hua Li ◽  
You Wu ◽  
Yun Cai ◽  
Hai-Liang Song ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Constructed Wetland ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Ammonium Nitrogen ◽  
Water Spinach ◽  
Nitrogen And Phosphorus ◽  
The Matrix ◽  
New Type ◽  
Nitrification And Denitrification

Rural runoff with abundant nutrients has become a great threat to aquatic environment. Hence, more and more attention has been focused on nutrients removal. In this study, an improved aerobic/anaerobic/aerobic three-stage water spinach constructed wetland (O-A-O-CW) was used to improve the removal of nitrogen and phosphorus of rural runoff. The removal rate of the target pollutants in O-A-O-CW was compared with the common matrix flow wetland as well as the no-plant wetland. The results showed that the O-A-O-CW significantly increased the chemical oxygen demand, total phosphorus, ammonium-nitrogen, nitrate, and total nitrogen removal rate, and the corresponding removal rate was 55.85%, 81.70%, 76.64%, 89.78%, and 67.68%, respectively. Moreover, the best hydraulic condition of the wetland, including hydraulic retention time and hydraulic loading, was determined, which were 2 days and 0.45 m3·m−2·day−1, respectively. Furthermore, the removal mechanism of the constructed wetland was thoroughly studied, which included the adsorption of nitrogen and phosphorus by the matrix and water spinach, and the nitrification and denitrification by the bacteria. The results demonstrated that the mechanisms of nitrogen removal in the new type wetland were principally by the nitrification and denitrification process. Additionally, adsorption and precipitation by the matrix are mainly responsible for phosphorus removal. These results suggested that the new O-A-O-CW can efficiently removal nutrients and enhance the water quality of the rural runoff.

Nitrogen removal and N2O emission by shunt distributing wastewater in aerated or non-aerated subsurface wastewater infiltration systems under different shunt ratios

2018 ◽  
Vol 78 (2) ◽  
pp. 329-338 ◽  
Author(s):  
Fanping Zheng ◽  
Yue Zhao ◽  
Zhiqi Li ◽  
Chaoquan Tan ◽  
Jing Pan ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Emission Rate ◽  
Oxygen Demand ◽  
N2o Emission ◽  
Functional Gene ◽  
Intermittent Aeration ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Functional Gene Abundance ◽  
Combined Strategy

Abstract This study investigated matrix oxidation–reduction potential (ORP), nitrogen removal, N2O emission and nitrogen removal functional gene abundance in three subsurface wastewater infiltration systems (SWISs), named SWIS A (without aeration or shunt distributing wastewater), SWIS B (with shunt distributing wastewater) and SWIS C (with intermittent aeration and shunt distributing wastewater) under different shunt ratios. Aerobic conditions were produced at a depth of 50 cm and anoxic or anaerobic conditions were not changed at depths of 80 and 110 cm by aeration in SWIS C. High average removal rates of chemical oxygen demand (COD) (83.1% for SWIS B, 90.9% for SWIS C), NH3-N (74.3% for SWIS B, 90.8% for SWIS C) and total nitrogen (TN) (61.1% for SWIS B, 87.9% for SWIS C) were obtained under shunt ratios of 1:3 and 1:2 for SWIS B and C, respectively. The lowest N2O emission rate (28.4 mg/(m2 d)) and highest nitrogen removal functional gene abundances were achieved in SWIS C under a 1:2 shunt ratio. The results suggested intermittent aeration and shunt distributing wastewater combined strategy would enhance nitrogen removal and reduce N2O emission for SWISs.

Effect of EM Techniques on Aquaculture Wastewater Purification

2015 ◽  
Vol 1092-1093 ◽  
pp. 838-843
Author(s):  
Long Wang ◽  
Ya Lu Shao ◽  
Li Hua Chen ◽  
Jie Liu ◽  
Xiao Hou Shao ◽  
...  
Keyword(s):  
Chemical Oxygen Demand ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Wastewater Purification ◽  
Technological Cooperation ◽  
Liquid Preparation ◽  
Active Calcium ◽  
Aquaculture Wastewater ◽  
Better Than

Through real-time monitoring of chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), total nitrogen (TN) and total phosphorus (TP) in the aquaculture wastewater, the purification effects of EM techniques by applying EM active calcium, Microbial nanoSilica Ball and both of them were studied. The results showed that the purification effect of solid preparation for Microbial nanoSilica Ball was better than that of the liquid preparation for EM active calcium. Moreover, the purification effect with the technological cooperation of Microbial nanoSilica Ball with EM active calcium reached best, indicating that the removal rate of COD, NH4+-N, TN and TP in the aquaculture wastewater was 72.12% , 73.85% , 64.99% and 67.87% respectively.

scholarly journals Pollutants Removal in Sewage Wastewater Efficiency and Kinetic of Ammonia Nitrogen Removal through Subsurface Vertical Flow Constructed Wetlands (SSVFCW)

2021 ◽  
pp. 22-37
Author(s):  
Dègninou Houndedjihou ◽  
Tomkouani Kodom ◽  
Delmira Beatriz Wolff ◽  
Luis Gustavo Marchioro ◽  
Thiago Augusto Formentini ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Nitrogen Removal ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Ammonia Removal ◽  
Phosphate Removal ◽  
Septic Tank ◽  
Subtropical Climate ◽  
Environment Temperature ◽  
Pollutants Removal

Aims: The removal of some pollutants such as ammonia nitrogen, Total Kjeldahl Nitrogen (TKN), chemical oxygen demand (COD), biological oxygen demand (BOD5), phosphate and some solids (total (TS), fixed (TFS) and volatile (TVS)) from sewage wastewater was investigated in vertical subsurface flow constructed wetlands (SSVFCW). Study Design: The bed of the constructed wetland is composed of gravel and Canna indica is used as vegetation. Place and Duration of Study: The study was conducted at the Federal University of Santa Maria, southern Brazil, under subtropical climate from June to September 2019. Methodology: Three kinds of samples of water collected (Raw, septic tank and outlet from the wetland) one time per week were analyzed according to American standards. Anions were analyzed by gas chromatography using 930 compact IC Flex Metrohm. Statistical analysis performed using ANOVA and U test of Mann-Whitneyto investigate the statistical difference were performed by STATISTICA and Origin software. Results: A total of 10 samples of each kind of water were collected and analyzed. In the conditions of this study, the removal percentage is 89.88, 88.00, 84.93, 84.62, 84.31, 72.94, 41.71, 15.63 respectively for COD, TKN, NH4+-N, TVS, BOD5, TS, TFS and PO43--P. Environment temperature, hydraulic retention time have an effect on the performance of the wetlands system. The effect of the contact time shows that adsorption process is a partway of ammonia nitrogen removal in the wetland. Among the three models of kinetic studied to describe the removal of ammonia nitrogen, Stover-Kincannon and second order models showed a better fit than the first order model. Conclusion: The nitrification and adsorption are the principal process of ammonia removal in the wetland. The plant has been found to be very efficient on the removal of ammonia nitrogen, TKN, COD, BOD5 while phosphate removal has been found too weak.

scholarly journals Digestate Liquid Fraction Treatment with Filters Filled with Recovery Materials

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 21
Author(s):  
Ilaria Piccoli ◽  
Giuseppe Virga ◽  
Carmelo Maucieri ◽  
Maurizio Borin
Keyword(s):  
Chemical Oxygen Demand ◽  
Total Nitrogen ◽  
Liquid Fraction ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Green Technology ◽  
Filling Material ◽  
Community Interactions ◽  
Material Particle ◽  
N Removal

Constructed wetlands (CWs) represent a green technology for digestate liquid fraction (DLF) treatment. However, previous research has warned about their performance when treating wastewater with high suspended solid and organic loads. In addition, the high NH4-N concentration typical of this wastewater can compromise vegetation establishment and activity. In view of this, a digestate pretreatment is needed. This study aimed to test the performance of filters filled with recovery materials, such as brick and refractory material, for DLF pretreatment. The effect on DLF physical (electrical conductivity, pH, dissolved oxygen, and temperature) and chemical (total nitrogen, ammonia–nitrogen, nitrate–nitrogen, total phosphorus, soluble phosphorus, and chemical oxygen demand) characteristics was monitored during eight weekly cycles. The effect of filtration on total nitrogen and ammonia–nitrogen removal began after about one month of loading, suggesting that an activation period is necessary for bacteria. For effective N removal, the presence of multiple digestate recirculations per day through the filters appears mandatory to guarantee the alternation of nitrification and denitrification conditions. For P removal, filling material particle size appeared to be more important than its composition. Unclear performances were observed considering chemical oxygen demand. Further studies on filling media and microbial community interactions, and the long-term efficiency of filters, are desirable.

Electrochemical oxidative degradation of indigo wastewater based on chlorine-containing system

2020 ◽  
Vol 49 (1) ◽  
pp. 46-54 ◽  
Author(s):  
Wei Zhang ◽  
Weiwei Lv ◽  
Xiaoyan Li ◽  
Jiming Yao
Keyword(s):  
Chemical Oxygen Demand ◽  
Response Surface ◽  
Electrochemical Oxidation ◽  
Surface Analysis ◽  
Removal Rate ◽  
Oxidative Degradation ◽  
Oxygen Demand ◽  
Single Factor ◽  
Dyeing Wastewater ◽  
Content Type

Purpose In this study, the oxidative degradation performance of indigo wastewater based on electrochemical systems was explored. The decolourization degrees, removal rate of chemical oxygen demand and biochemical oxygen demand of the indigo wastewater after degradation were evaluated and optimized treatment conditions being obtained. Design/methodology/approach The single factor method was first used to select the electrolyte system and electrode materials. Then the response surface analysis based on Box–Behnken Design was chosen to determine the influence of four independent variables such as FeCl3 concentration, NaCl concentration, decolourization time and voltage on the degradation efficiency. Findings On the basis of single factor experiment, the electrode material of stainless steel was selected in the double cell, and the indigo wastewater was electrolyzed with FeCl3 and NaCl electrolytes. The process conditions of electrochemical degradation of indigo wastewater were optimized by response surface analysis: the concentration of FeCl3 and NaCl was of 16 and 9 g/L, respectively, with a decolourization time of 50 min, voltage of 10 V and decolourization percentage of 98.94. The maximum removal rate of chemical oxygen demand reached 75.46 per cent. The highest ratio of B/C was 3.77, which was considered to be more biodegradable. Research limitations/implications Dyeing wastewater is bringing out more and more pollution problems to the environment. However, there are some shortcomings in traditional technologies such as adsorption and filtration. As a kind of efficient and clean water treatment technology, electrochemical oxidation has been applied to the treatments of various types of wastewater. The decolourization and degradation of indigo wastewater is taken as an example to provide reference for the treatment of wastewater in actual plants. Practical implications The developed method provided a simple and practical solution for efficiently degrading indigo wastewater. Originality/value The method for the electrochemical oxidation technology was novel and could find numerous applications in the degradation of printing and dyeing wastewater.

Does intermittent aeration and/or an influent distributary affect nitrogen removal and nitrous oxide emission of an ecological soil wastewater infiltration system?

2019 ◽  
Vol 79 (7) ◽  
pp. 1417-1425 ◽  
Author(s):  
Yue Zhao ◽  
Zhiyu Zhang ◽  
Ziqi Li ◽  
Shiyao Wang ◽  
Chaoquan Tan ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Nitrogen Removal ◽  
Emission Rate ◽  
N2o Emission ◽  
Functional Genes ◽  
Intermittent Aeration ◽  
Anaerobic Conditions ◽  
N Removal ◽  
The Matrix ◽  
Removal Efficiencies

Abstract The effect of intermittent aeration and an influent distributary on NH4+-N removal, total nitrogen (TN) removal, nitrous oxide (N2O) emission and the abundances of nitrogen removal and N2O emission functional genes in four types of ecological soil wastewater infiltration systems (ESWISs) (which were conventional ESWIS 1 (operated without aeration and influent distributary), ESWIS 2 (operated with intermittent aeration), ESWIS 3 (operated with influent distributary) and ESWIS 4 (operated with intermittent aeration and influent distributary)) were studied. Intermittent aeration in ESWIS 2 and 4 created aerobic conditions above 50 cm depth of the matrix and anoxic or anaerobic conditions in the lower matrix (below 80 cm depth). ESWIS 4 improved NH4+-N (to 90.1%) and TN (to 87.8%) removal efficiencies and increased the abundances of eight nitrogen removal and N2O emission functional genes (amoA, nxrA, narG, napA, nirS, nirK, qnorB and nosZ) in contrast with other ESWISs. The combination of intermittent aeration and influent distributary achieved the lowest N2O emission rate of 34.7 mg/(m2 d) in ESWIS 4. Intermittent aeration combined with influent distributary was recommended for ESWISs to enhance nitrogen removal and reduce N2O emission.

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