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Analysis of the Correlation among Three Oxygen Demand Indexes in Surface Water
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作者 Bin YANG Jing LIU Jinglong LIU 《Meteorological and Environmental Research》 CAS 2022年第2期61-64,共4页
Based on the monitoring data of chemical oxygen demand(COD),permanganate index(I Mn)and five-day biochemical oxygen demand(BOD 5)of surface water in Tongling section of Yangtze River,the linear relationship among the ... Based on the monitoring data of chemical oxygen demand(COD),permanganate index(I Mn)and five-day biochemical oxygen demand(BOD 5)of surface water in Tongling section of Yangtze River,the linear relationship among the three indexes in the annual data analysis and the internal reasons,as well as the linear relationship and changes among the three indexes in different seasons were analyzed.The results reveal that in terms of the whole year,COD,I Mn and BOD 5 had a significant correlation and good linear relationship.The fitting slopes of the three indexes were 3.89 of COD/I Mn,4.39 of COD/BOD 5 and 1.16 of I Mn/BOD 5,respectively,which corresponded to the proportional relationship among the three indexes.From the perspective of seasonal changes,there was a very significant correlation between the three indexes in spring and summer.In autumn and winter,only COD and I Mn had a good correlation,but they had a poor correlation with BOD 5. 展开更多
关键词 Chemical oxygen demand Permanganate index Biochemical oxygen demand SEASON CORRELATION
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Chemical oxygen demand reduction in coffee wastewater through chemical flocculation and advanced oxidation processes 被引量:7
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作者 ZAYAS Pérez Teresa GEISSLER Gunther HERNANDEZ Fernando 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第3期300-305,共6页
The removal of the natural organic matter present in coffee processing wastewater through chemical coagulation-flocculation and advanced oxidation processes (AOP) had been studied. The effectiveness of the removal o... The removal of the natural organic matter present in coffee processing wastewater through chemical coagulation-flocculation and advanced oxidation processes (AOP) had been studied. The effectiveness of the removal of natural organic matter using commercial flocculants and UV/H202, UV/O3 and UV/H2O2/O3 processes was determined under acidic conditions. For each of these processes, different operational conditions were explored to optimize the treatment efficiency of the coffee wastewater. Coffee wastewater is characterized by a high chemical oxygen demand (COD) and low total suspended solids. The outcomes of coffee wastewater treatment using coagulation-flocculation and photodegradation processes were assessed in terms of reduction of COD, color, and turbidity. It was found that a reduction in COD of 67% could be realized when the coffee wastewater was treated by chemical coagulation-flocculation with lime and coagulant T-1. When coffee wastewater was treated by coagulation-flocculation in combination with UV/H2O2, a COD reduction of 86% was achieved, although only after prolonged UV irradiation. Of the three advanced oxidation processes considered, UV/H2O2, UV/O3 and UV/H2O2/O3, we found that the treatment with UV/H2O2/O3 was the most effective, with an efficiency of color, turbidity and further COD removal of 87%, when applied to the flocculated coffee wastewater. 展开更多
关键词 advanced oxidation processes coagulation-flocculation: coffee wastewater chemical oxygen demand (COD)
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Environmental capacity of chemical oxygen demand in the Bohai Sea: modeling and calculation 被引量:5
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作者 赵喜喜 王修林 +2 位作者 石晓勇 李克强 丁东生 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2011年第1期46-52,共7页
A three-dimensional advection-diffusion model coupled with the degradation process is established for describing the transport of chemical oxygen demand (COD). Comparison of the simulated distribution of COD at the su... A three-dimensional advection-diffusion model coupled with the degradation process is established for describing the transport of chemical oxygen demand (COD). Comparison of the simulated distribution of COD at the surface in the Bohai Sea in August, 2001 with field observations, shows that the model simulates the dataset reasonably well. The Laizhou Bay, Bohai Bay, and Liaodong Bay were contaminated heavily near shore. Based on the optimal discharge flux method, the Environmental Capacity (EC) and allocated capacities of COD in the Bohai Sea are calculated. For seawater of Grades I to IV of the Chinese National Standard, the ECs of COD in the Bohai Sea were 77×104 t/a, 116×104 t/a, 154×104 t/a and 193×104 t/a, respectively. The Huanghe (Yellow) River pollutant discharge accounted for the largest percentage of COD at 14.3%, followed by that of from the Liugu River (11.5%), and other nine local rivers below 10%. The COD level in 2005 was worse than that of Grade II seawater and was beyond the environmental capacity. In average, 35% COD reduction is called to meet the standard of Grade I seawater. 展开更多
关键词 Bohai Sea environmental capacity (EC) chemical oxygen demand (COD) degradation process
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Spatial distribution and diurnal variation of chemical oxygen demand at the beginning of the rainy season in the Changjiang (Yangtze) River Estuary 被引量:3
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作者 高学鲁 宋金明 +1 位作者 李宁 李学刚 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2007年第3期254-260,共7页
A field observation was carried out in the Changjiang (Yangtze) River Estuary from May 19 to 26, 2003. A total of 29 stations, including 2 anchored stations, were occupied through almost the whole salinity gradient. B... A field observation was carried out in the Changjiang (Yangtze) River Estuary from May 19 to 26, 2003. A total of 29 stations, including 2 anchored stations, were occupied through almost the whole salinity gradient. Based on the observation data, biogeochemistry of chemical oxygen demand (COD) was examined. Spatial distribution pattern of COD shows that it decreased downstream. The COD concentration varied generally within a narrow range of 1.24–1.60 mg/L in the zone around the river mouth, beyond which it decreased rapidly to 0.20 mg/L. In the mixed water zone, the fluctuation in COD was smaller at 2 m above the bottom layer than at the surface layer in 48 h. In the seawater zone, the 48-h fluctuation at the surface was the largest, followed by that of 5 m below the surface and 2 m above the bottom layers in a range of from 2.50 to 0.55 mg/L. Freshwater discharge was the dominant source of COD in the estuary. The average COD beyond the river mouth was 2.7 mg/L, which accorded with the Chinese seawater quality Grade I. Relationships between dissolved oxygen and biogeochemical parameters such as suspended particulate matter, dissolved organic matter and chlorophyll-a were also discussed. 展开更多
关键词 spatial distribution diurnal variation chemical oxygen demand the Changjiang (Yangtze) River Estuary
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On-Line Measurement of the Chemical Oxygen Demand in Wastewater in a Pulp and Paper Mill Using Near Infrared Spectroscopy 被引量:5
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作者 John Dahlbacka Josefina Nystrom +2 位作者 Torgny Mossing Paul Geladi Tom Lillhonga 《Spectral Analysis Review》 2014年第4期19-25,共7页
Although near infrared (NIR) spectroscopy has been evaluated for numerous applications, the number of actual on-line or even on-site industrial applications seems to be very limited. In the present paper, the attempts... Although near infrared (NIR) spectroscopy has been evaluated for numerous applications, the number of actual on-line or even on-site industrial applications seems to be very limited. In the present paper, the attempts to produce online predictions of the chemical oxygen demand (COD) in wastewater from a pulp and paper mill using NIR spectroscopy are described. The task was perceived as very challenging, but with a root mean square error of prediction of 149 mg/l, roughly corresponding to 1/10 of the studied concentration interval, this attempt was deemed as successful. This result was obtained by using partial least squares model regression, interpolated reference values for calibration purposes, and by evenly distributing the calibration data in the concentration space. This work may also represent the first industrial application of online COD measurements in wastewater using NIR spectroscopy. 展开更多
关键词 Chemical oxygen demand (COD) Industrial Wastewater Near Infrared Spectroscopy (NIR) Multivariate Calibration On-Line Measurement
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Simultaneous Determination of Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD5) in Wastewater by Near-Infrared Spectrometry 被引量:6
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作者 Qiong YANG Zhenyao LIU Jidong YANG 《Journal of Water Resource and Protection》 2009年第4期286-289,共4页
To rapidly determine the pollution extent of wastewater, the calibration models were established for deter-mination of Chemical Oxygen Demand and Biological Oxygen Demand in wastewater by partial least squares and nea... To rapidly determine the pollution extent of wastewater, the calibration models were established for deter-mination of Chemical Oxygen Demand and Biological Oxygen Demand in wastewater by partial least squares and near infrared spectrometry of 120 samples. Spectral data preprocessing and outliers’ diagnosis were also discussed. Correlation coefficients of the models were 0.9542 and 0.9652, and the root mean square error of prediction (RMSEP) were 25.24 mg?L-1 and 12.13 mg?L-1 in the predicted range of 28.40~528.0 mg?L-1 and 16.0~305.2 mg?L-1 for Chemical Oxygen Demand and Biological Oxygen Demand, respectively. By statistical significance test, the results of determination were compared with those of stan-dard methods with no significant difference at 0.05 level. The method has been applied to simultaneous de-termination of Chemical Oxygen Demand and Biological Oxygen Demand in wastewater with satisfactory results. 展开更多
关键词 Near-Infrared SPECTROMETRY WASTEWATER BIOLOGICAL oxygen demand Chemical oxygen demand
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Soft Computing of Biochemical Oxygen Demand Using an Improved T–S Fuzzy Neural Network 被引量:4
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作者 乔俊飞 李微 韩红桂 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2014年第Z1期1254-1259,共6页
It is difficult to measure the online values of biochemical oxygen demand(BOD) due to the characteristics of nonlinear dynamics, large lag and uncertainty in wastewater treatment process. In this paper, based on the k... It is difficult to measure the online values of biochemical oxygen demand(BOD) due to the characteristics of nonlinear dynamics, large lag and uncertainty in wastewater treatment process. In this paper, based on the knowledge representation ability and learning capability, an improved T–S fuzzy neural network(TSFNN) is introduced to predict BOD values by the soft computing method. In this improved TSFNN, a K-means clustering is used to initialize the structure of TSFNN, including the number of fuzzy rules and parameters of membership function. For training TSFNN, a gradient descent method with the momentum item is used to adjust antecedent parameters and consequent parameters. This improved TSFNN is applied to predict the BOD values in effluent of the wastewater treatment process. The simulation results show that the TSFNN with K-means clustering algorithm can measure the BOD values accurately. The algorithm presents better approximation performance than some other methods. 展开更多
关键词 BIOCHEMICAL oxygen demand WASTEWATER treatment T–S fuzzy NEURAL network K-MEANS clustering
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IN-SITU DETERMINATION OF SEDIMENT OXYGEN DEMAND IN CULTIVATION PONDS
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作者 孙耀 陈聚法 +1 位作者 殷丽 宋云利 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2000年第2期157-161,共5页
This paper presents a method for in situ determining sediment oxygen demand (SOD) in cultivation pond. This method based on sediment surface structure, temperature, and other determining conditions like those in shrim... This paper presents a method for in situ determining sediment oxygen demand (SOD) in cultivation pond. This method based on sediment surface structure, temperature, and other determining conditions like those in shrimp cultivation environments, overcomes defects of old methods and provides more accurate estimation of SOD’s effect on dissolved oxygen in culture waters. Our experiment shows that the sediment surface structure and temperature had important effect on SOD in culture water. Different SOD values were derived from different parts of oxygen consumption curves of sediment, because the curves were not linear. According to the oxygen consumption curves of sediment and saturated DO in culture water, it was thought more suitable to calculate SOD with dissolved oxygen reduction from 5.0 to 2.0 mg/l. This method to determine the SOD of shrimp ponds yielded satisfactory results. 展开更多
关键词 SEDIMENT oxygen demand CULTIVATION PONDS in SITU DETERMINATION
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Sediment Oxygen Demand of a Leachate Pond at an Offshore Municipal Solid Waste Disposal Site 2 Years after the Site Was Closed
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作者 Shogo Sakita Jun Nishimoto Kazuyuki Nishimura 《Journal of Geoscience and Environment Protection》 2018年第4期181-193,共13页
Various water quality parameters of a leachate pond at an offshore municipal solid waste disposal site were monitored. The pH, dissolved oxygen (DO), and water temperature at the bottom of the leachate pond were measu... Various water quality parameters of a leachate pond at an offshore municipal solid waste disposal site were monitored. The pH, dissolved oxygen (DO), and water temperature at the bottom of the leachate pond were measured during Sep. (the 1st period) and Nov.-Dec. (the 2nd period) of 2011. The results suggested that the stratification of water temperature in the pond had gradually broken down due to convection occurring between the end of the 1st period and the 2nd period. The pH was almost constant at 10 - 11 during the 1st period and was approximately 11.5 during the 2nd period. The DO was almost zero during both periods. An anaerobic batch experiment with sampled sediment was undertaken to elucidate the mechanism of material leaching from the sediment. DO decreased under all experimental conditions. With respect to oxidation reduction potential (ORP) and total sulfide in addition to DO, the condition most closely mimicking that of the site became the most anaerobic. The average sediment oxygen demand, SODave, was calculated using a brief numerical model based on batch experiment data. The SODave was 1114.7 mg/m2/d, indicating that at least 434 g/d of oxygen must be supplied to the leachate pond to maintain the DO. 展开更多
关键词 OFFSHORE Disposal SITE LEACHATE POND SEDIMENT SEDIMENT oxygen demand
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Chemical oxygen demand oxidation via sustained-release persulfate balls: a rate-compatibility study of flow velocity, releasing, and oxidation
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作者 Bate BATE Danting ZHANG +3 位作者 Jianshe YE Min XIA Yixin YANG Shuai ZHANG 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2024年第9期749-762,共14页
Identification of chemical oxygen demand(COD)in municipal solid waste(MSW)landfill leachates is a challenging problem.This paper investigated the feasibility of using sodium persulfate(PS),a strong oxidant,as a permea... Identification of chemical oxygen demand(COD)in municipal solid waste(MSW)landfill leachates is a challenging problem.This paper investigated the feasibility of using sodium persulfate(PS),a strong oxidant,as a permeable reactive barrier(PRB)filling material.Firstly,sustained-release persulfate balls were manufactured to adjust the release rate of persulfate,the oxidation agent.In addition,Fe(II)-loaded activated carbon(Fe-AC)was used to help with an even distribution of Fe(II)in the porous medium(PRB in this case).Then,the oxidation efficiency and kinetic rate of COD removal by the sustained-release balls were subjected to batch tests.A mass ratio of 1:1.4:0.24:0.7 for PS:cement:sand:water was the most efficient for COD removal(95%).The breakthrough curve for a 5 mm sustained-release ball revealed that the retardation factor was 1.27 and that the hydrodynamic dispersion coefficient was 15.6 cm^(2)/d.The corresponding half-life of COD oxidation was 0.43 d,which was comparable with the half-life of PS release from sustained-release balls(0.56 d).The sustained-release persulfate balls were shown to be an economical material with a simple recipe and production method when catalyzed by Fe-AC.Compared with cutting-edge methods,sustained-release balls used in PRBs offer significant advantages in terms of both effectiveness and economy for the preparation of sustained-release and catalytic materials.These results verified the feasibility of using sustained-release persulfate balls as a PRB material for COD removal. 展开更多
关键词 Chemical oxygen demand(COD) Sodium persulfate(PS) Sustained-release balls Permeable reactive barrier(PRB) Fe(II)-loaded activated carbon(Fe-AC)
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A new FTO/TiO_(2)/PbO_(2)electrode for eco-friendly electrochemical determination of chemical oxygen demand
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作者 Lei Wang Yuehan Zhang +3 位作者 Xiaoxuan Sun Yunhui Li Junfeng Zhai Shaojun Dong 《Nano Research》 SCIE EI CSCD 2023年第8期11042-11047,共6页
Eco-friendly chemical oxygen demand(COD)sensors are highly desired with respect to the importance of COD determination in environmental protection.In this work,a new FTO/TiO_(2)/PbO_(2)(FTO=fluorine-doped tin oxide)el... Eco-friendly chemical oxygen demand(COD)sensors are highly desired with respect to the importance of COD determination in environmental protection.In this work,a new FTO/TiO_(2)/PbO_(2)(FTO=fluorine-doped tin oxide)electrode was fabricated with a two-step method and used as an eco-friendly electrochemical COD sensor.The interlayer TiO_(2)was employed to strengthen the adhesion of PbO_(2)on the FTO substrates by providing a large TiO_(2)/PbO_(2)interface area.The effects of the factors including applied potential,supporting electrolyte concentration and stirring speed on the sensing performance were investigated.Under the optimized conditions,linear responses to the COD of water with different COD sources were achieved,and a linear range from 5 to 120 mg/L was obtained in the case of sucrose as the COD source.The relative standard deviations(RSD)were determined to be less than 9%for the glucose solutions with the COD of 7.5,12.5 and 17.5 mg/L.For real sample analysis,the obtained results were comparable with those measured with the conventional dichromate method,with a relative error less than 11%. 展开更多
关键词 chemical oxygen demand organic pollution chloride interference PbO_(2)electrode
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The liver-to-spleen ratio is a risk factor predicting oxygen demand in COVID-19 patients
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作者 Hiromasa Nakayasu Shogo Sakurai +12 位作者 Shuichi Sugiyama Kotaro Shiratori Kohei Okawa Yoshihiro Kitahara Shingo Takahashi Toshihiro Masuda Yutaro Kishimoto Mika Saigusa Akito Yamamoto Taisuke Akamatsu Satoru Morita Kazuhiro Asada Toshihiro Shirai 《Infectious Medicine》 2023年第2期105-111,共7页
Background:We aimed to investigate risk factors predicting oxygen demand in COVID-19 patients.Methods:Patients admitted to Shizuoka General Hospital with COVID-19 from August 2020 to August 2021 were included.First,we... Background:We aimed to investigate risk factors predicting oxygen demand in COVID-19 patients.Methods:Patients admitted to Shizuoka General Hospital with COVID-19 from August 2020 to August 2021 were included.First,we divided patients into groups with and without oxygen demand.Then,we compared patients’clinical characteristics and laboratory and radiological findings to determine factors predicting oxygen demand.Results:One hundred seventy patients with COVID-19(aged 58±15 years,57 females)were enrolled.Common comorbidities were cardiovascular diseases(47.6%),diabetes mellitus(28.8%),and dyslipidemia(26.5%).Elder age,higher body mass index,cardiovascular diseases,diabetes mellitus,lower lymphocyte count,albumin,hep-atic attenuation value,and the liver-to-spleen ratio(L/S),higher D-dimer,aspartate aminotransferase,lactate dehydrogenase,troponin-T,C-reactive protein,KL-6,chest and abdominal circumference,and visceral fat were found in patients with oxygen demand.According to the multivariate logistic regression analysis,L/S,lympho-cyte count,D-dimer,and abdominal circumference under the diaphragm were independent risk factors predicting oxygen demand in COVID-19 patients.Conclusions:On admission,L/S,lymphocyte count,D-dimer,and abdominal circumference were predictive factors for oxygen demand.These factors may help in the appropriate triage of COVID-19 patients in the decision to admit them to the hospital. 展开更多
关键词 COVID-19 SARS-CoV-2 oxygen demand The liver-to-spleen ratio Abdominal circumference
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Photocatalytic Oxidation for Determination of Chemical Oxygen Demand Using Nano-TiO2 Film 被引量:4
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作者 丁红春 柴怡浩 +4 位作者 张中海 刘梅川 鲜跃仲 潘振声 金利通 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2005年第10期1425-1429,共5页
A photocatalytic oxidation method for determination of chemical oxygen demand (COD) using nano-TiO2 film, based on the use of a nano-TiO2-Ce(SO4)2 system and electrochemical detection, was proposed. The technique ... A photocatalytic oxidation method for determination of chemical oxygen demand (COD) using nano-TiO2 film, based on the use of a nano-TiO2-Ce(SO4)2 system and electrochemical detection, was proposed. The technique was originated from the direct determination of the Ce(Ⅲ) concentration change resulting from photocatalytic oxidation of organic compounds. Ce(Ⅲ), which was produced by photocatalytic reduction of Ce(SO4)2, could be measured at a multi-walled carbon nanotubes (MWNT) chemically modified electrode (CME). The COD values by this method were calculated from the differential pulse voltammetry (DPV) current of Ce(Ⅲ) at the CME. Under the optimal operation conditions, the detection limit of 0.5 mg·L^-1 COD with the linear range of 1-600 mg·L^-1 was achieved. This method was also applied to determination of various COD of ground water and wastewater samples. The resuits were in good agreement with those from the conventional COD methods, i.e., permanganate and dichromate ones. 展开更多
关键词 photocatalytic oxidation chemical oxygen demand electrochemical detection nano-TiO2 film
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Inhibitory effect of nitrobenzene on oxygen demand in lake sediments 被引量:2
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作者 Xiaohong Zhou Xuying Wang Hanchang Shi 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2012年第5期934-939,共6页
Nitrobenzene is an important raw material and product, which presents a heavy threat to the ecosystem. The potential impacts of nitrobenzene on sediment oxygen demand (SOD) were studied in lake sediment simulating r... Nitrobenzene is an important raw material and product, which presents a heavy threat to the ecosystem. The potential impacts of nitrobenzene on sediment oxygen demand (SOD) were studied in lake sediment simulating reactors receiving relatively low inputs of nitrobenzene. Oxygen microprofiles were measured in these sediment reactors using microelectrodes. After an initial microprofile measurement as a control, nitrobenzene was added to the overlying water resulting in concentrations of 0, 50, 100, and 150 μg/L. Microprofiles were measured on day 1, 2, 4 and 7 following the addition of nitrobenzene. SODs were determined from the microprofiles using a reaction-diffusion model. Results showed that the SODs increased relative to the initial values measured in the pre-treatment period in reactors exposed to all nitrobenzene concentrations on day 1. However, the values decreased gradually on the following days, which eventually resulted in a 50% loss in SODs after 7 days of exposure to nitrobenzene in all reactors. In addition, the inhibition effect of nitrobenzene on SOD exhibited a weak relationship with its concentration. The microscopic observation and count of algae in the sediment showed that the exposure to nitrobenzene did not change the composition of algae greatly, however, it decreased the number of dominant algae species sharply after 7 days of exposure. These results suggested that nitrobenzene could significantly alter SOD in lakes, which could ultimately affect the pollutant recovery in aquatic-sediment systems. 展开更多
关键词 NITROBENZENE SEDIMENT inhibitory effect MICROELECTRODE sediment oxygen demand
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Excessive greenhouse gas emissions from wastewater treatment plants by using the chemical oxygen demand standard 被引量:1
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作者 Zongqing LV Xiaoyu SHAN +3 位作者 Xilin XIAO Ruanhong CAI Yao ZHANG Nianzhi JIAO 《Science China Earth Sciences》 SCIE EI CSCD 2022年第1期87-95,共9页
Chemical oxygen demand(COD)is widely used as an organic pollution indicator in wastewater treatment plants.Large amounts of organic matter are removed during treatment processes to meet environmental standards,and con... Chemical oxygen demand(COD)is widely used as an organic pollution indicator in wastewater treatment plants.Large amounts of organic matter are removed during treatment processes to meet environmental standards,and consequently,substantial greenhouse gases(GHGs)such as methane(CH_(4))are released.However,the COD indicator covers a great amount of refractory organic matter that is not a pollutant and could be a potential carbon sink.Here,we collected and analysed COD data from 86 worldwide municipal wastewater treatment plants(WWTPs)and applied a model published by the Intergovernmental Panel on Climate Change to estimate the emission of CH_(4) due to recalcitrant organic compound processing in China’s municipal wastewater treatment systems.Our results showed that the average contribution of refractory COD to total COD removal was55%in 86 WWTPs.The amount of CH_(4) released from the treatment of recalcitrant organic matter in 2018 could have been as high as 38.22 million tons of carbon dioxide equivalent,which amounts to the annual carbon sequestered by China’s wetlands.This suggests that the use of COD as an indicator for organic pollution is undue and needs to be revised to reduce the emission of GHG.In fact,leaving nontoxic recalcitrant organic matter in the wastewater may create a significant carbon sink and will save energy during the treatment process,aiming at carbon neutrality in the wastewater treatment industry. 展开更多
关键词 Chemical oxygen demand Wastewater treatment Recalcitrant dissolved organic matter Greenhouse gas emission
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A pilot scale trickling filter with pebble gravel as media and its performance to remove chemical oxygen demand from synthetic brewery wastewater
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作者 Haimanot HABTE LEMJI Hartmut ECKST DT 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2013年第10期924-933,共10页
Evaluating the performance of a biotrickling filter for the treatment of wastewaters produced by a company manufacturing beer was the aim of this study.A pilot scale trickling filter filled with gravel was used as the... Evaluating the performance of a biotrickling filter for the treatment of wastewaters produced by a company manufacturing beer was the aim of this study.A pilot scale trickling filter filled with gravel was used as the experimental biofilter.Pilot scale plant experiments were made to evaluate the performance of the trickling filter aerobic and anaerobic biofilm systems for removal of chemical oxygen demand(COD) and nutrients from synthetic brewery wastewater.Performance evaluation data of the trickling filter were generated under different experimental conditions.The trickling filter had an average efficiency of(86.81±6.95)% as the hydraulic loading rate increased from 4.0 to 6.4 m3/(m2·d).Various COD concentrations were used to adjust organic loading rates from 1.5 to 4.5 kg COD/(m3·d).An average COD removal efficiency of(85.10±6.40)% was achieved in all wastewater concentrations at a hydraulic loading of 6.4 m3/(m2·d).The results lead to a design organic load of 1.5 kg COD/(m3·d) to reach an effluent COD in the range of 50–120 mg/L.As can be concluded from the results of this study,organic substances in brewery wastewater can be handled in a cost-effective and environmentally friendly manner using the gravel-filled trickling filter. 展开更多
关键词 BIODEGRADATION Pilot scale trickling filter Aerobic treatment Brewery wastewater Chemical oxygen demand(COD) Trickling filter performance
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Effects of benthic hydraulics on sediment oxygen demand in a canyon-shaped deep drinking water reservoir:Experimental and modeling study
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作者 Nan Li Tinglin Huang +1 位作者 Zhiying Chang Kai Li 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2021年第4期226-234,共9页
Sediment oxygen demand(SOD)is a major contributor to hypolimnetic oxygen depletion and the release of internal nutrient loading.By measuring the SOD in experimental chambers using in both dissolved oxygen(DO)depletion... Sediment oxygen demand(SOD)is a major contributor to hypolimnetic oxygen depletion and the release of internal nutrient loading.By measuring the SOD in experimental chambers using in both dissolved oxygen(DO)depletion and diffusional oxygen transfer methods,a model of SOD for a sediment bed with water current-induced turbulence was presented.An experimental study was also performed using near-sediment vertical DO profiles and correlated hydraulic parameters stimulated using a computational fluid dynamics model to determine how turbulences and DO concentrations in the overlying water affects SOD and diffusive boundary layer thickness.The dependence of the oxygen transfer coefficient and diffusive boundary layer on hydraulic parameters was quantified,and the SOD was expressed as a function of the shear velocity and the bulk DO concentrations.Theoretical predictions were validated using microelectrode measurements in a series of laboratory experiments.This study found that flow over the sediment surface caused an increase in SOD,attributed to enhanced sediment oxygen uptake and reduced substances fluxes,i.e.,for a constant maximum biological oxygen consumption rate,an increased current over the sediment could increase the SOD by 4.5 times compared to stagnant water.These results highlight the importance of considering current-induced SOD increases when designing and implementing aeration/artificial mixing strategies. 展开更多
关键词 Sediment oxygen demand Sediment-water flux Diffusive boundary layer thickness Turbulence Biological oxygen consumption
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Study on Determination of Chemical Oxygen Demand in Water with Ion Chromatography
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作者 张中海 丁红春 +2 位作者 方艳菊 鲜跃仲 金利通 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2007年第2期228-232,共5页
A new method for determining chemical oxygen demand (COD) value in water using ion chromatography coupled with nano TiO2-K2S2O8 co-existing system was described. The photocatalytic oxidation system and nano TiO2-K2S... A new method for determining chemical oxygen demand (COD) value in water using ion chromatography coupled with nano TiO2-K2S2O8 co-existing system was described. The photocatalytic oxidation system and nano TiO2-K2S2O8 co-existing system could degrade the organic compounds in water. All sulfur-containing species in the reactive solution were eventually transformed to sulfate which could be determined by conductivity detector in ion chromatography. The change of conductivity of sulfate was proportional to COD value. The optimal experimental conditions and the mechanism of the detection were discussed. The application range was 10.0-300.0 mg·L^-1 and the lowest limit of detection was 3.5 mg·L^-1. It was considered that the value obtained could be reliably correlated with the COD value obtained using the conventional methods. 展开更多
关键词 ion chromatography chemical oxygen demand nano TiO2-K2S2O8
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基于KPCA-PSO-ELM算法的地表水化学需氧量紫外-可见吸收光谱检测研究 被引量:1
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作者 郑培超 周椿棪 +5 位作者 王金梅 尹义同 张莉 吕强 曾金锐 何雨欣 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2024年第3期707-713,共7页
化学需氧量(COD)是水质检测重要指标之一,反映水体有机物含量。传统的COD化学检测方法存在操作繁琐,等待时间长,二次污染等缺点。紫外-可见吸收光谱法是目前水体化学需氧量检测中应用最为广泛的方法之一,具有检测快速、无污染等特点。... 化学需氧量(COD)是水质检测重要指标之一,反映水体有机物含量。传统的COD化学检测方法存在操作繁琐,等待时间长,二次污染等缺点。紫外-可见吸收光谱法是目前水体化学需氧量检测中应用最为广泛的方法之一,具有检测快速、无污染等特点。为了满足地表水化学需氧量快速、实时、在线监测等要求,采用紫外-可见吸收光谱进行测量,提出了内核主成分分析(KPCA)结合粒子群优化极限学习机(PSO-ELM)预测模型,满足当前对地表水化学需氧量快速、实时监测的要求。对光谱进行Savitzky-Golay(SG)滤波以降低随机噪声的影响;用积分光谱代替原光谱,以降低信号波动带来的影响;再将得到的光谱信息归一化,消除不同光谱数据量纲的影响。将预处理后的数据利用KPCA算法将全光谱数据压缩为5个特征,有效解决光谱信息冗余的问题;采用PSO算法对ELM的权重和偏置进行优化极大提高了模型的精度。对217个河流、长江及支流、湖库等地表水样本按照7∶3随机划分成训练集和测试集,并进行建模测试,其中训练集拟合优度(R2)为0.930 2、均方根误差(RMSE)为0.363 0 mg·L^(-1)、测试集拟合优度R2为0.931 9、均方根误差(RMSE)为0.400 7 mg·L^(-1)。为了验证提出的基于KPCA全光谱数据压缩方法对预测模型的提升效果,分别对比了主成分分析(PCA)、连续投影算法(SPA)、套索回归(LASSO)等特征处理算法。PCA-PSO-ELM模型的RMSE为0.715 1 mg·L^(-1)、 SPA-PSO-ELM模型的RMSE为0.473 7 mg·L^(-1)、 LASSO-PSO-ELM模型的RMSE为0.412 6 mg·L^(-1), KPCA-PSO-ELM模型较上述三种模型,RMSE分别降低了78.46%、 18.22%、 2.97%,结果表明KPCA是一种高效的光谱降维算法,能够有效消除光谱冗余信息,提升模型预测精度。基于KPCA-PSO-ELM预测模型结合紫外-可见吸收光谱可以实现对地表水COD快速、实时检测,为在线COD检测场景提供方法支撑。 展开更多
关键词 化学需氧量 紫外-可见吸收光谱 内核主成分分析 极限学习机
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PVDF/PVA共混膜的制备及其在去除污水COD中的应用
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作者 张爱文 种延竹 高官俊 《合成树脂及塑料》 CAS 北大核心 2024年第4期32-35,共4页
以聚乙烯醇(PVA)、聚偏氟乙烯(PVDF)为原料,聚乙烯吡咯烷酮为溶剂,制备了PVDF/PVA共混膜。将该膜应用于膜生物反应器处理污水,测试化学需氧量(COD)去除率和膜的使用性能。结果表明:膜的水通量随PVA加入量的增加而逐渐增加,在牵伸比为1.7... 以聚乙烯醇(PVA)、聚偏氟乙烯(PVDF)为原料,聚乙烯吡咯烷酮为溶剂,制备了PVDF/PVA共混膜。将该膜应用于膜生物反应器处理污水,测试化学需氧量(COD)去除率和膜的使用性能。结果表明:膜的水通量随PVA加入量的增加而逐渐增加,在牵伸比为1.7时,膜的水通量达到最大值;平板膜用清水清洗后,膜的水通量恢复率较高,膜的运行周期经第一次清洗后下降了18 h,经第二次和第三次清洗后,膜的运行周期基本稳定在6~8 h,COD去除率高于90%,表明该膜具有良好的使用性能。 展开更多
关键词 聚偏氟乙烯 聚乙烯醇 共混膜 生物处理 水通量 化学需氧量
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