外文原文-接种活性污泥的生物滴滤池处理氯苯的性能研究.pdf

Procedia Environmental Sciences 18 2013 391 396 1878 0296 2013 The Authors Published by Elsevier B V Selection and peer review under responsibility of Beijing Institute of Technology doi 10 1016 j proenv 2013 04 052 Available online at 2013 International Symposium on Environmental Science and Technology 2013 ISEST Performance of biotrickling filter inoculated with activated sludge for chlorobenzene removal Bairen Yanga Xian Niua b Cheng Dinga Xiaojiang Xua Dongxue Liua b aSchool of Environmental Science and Engineering Yancheng Institute of Technology Jiangsu Yancheng 224051 China bSchool of the Environment Jiangsu University Jiangsu Zhenjiang212013 China Abstract Activated carbon fibers and multi surface hollow balls were used to establish biotrickling filter BTF and the acclimated sludge was inoculated on surface of packing to purify waste gas containing chlorobenzene The BTF performance was examined under different conditions in steady state Results showed that the maximum removal efficiency RE could be reached under the condition of chlorobenzene initial concentration of 878 53 1522 48 mg m 3 and the empty bed retention time EBRT of 56 s while the average removal efficiency was 91 34 EBRT of 45 s was determined appropriately and the maximum chlorobenzene removal rate of 102 79 g m 3 h had been achieved under the condition of chlorobenzene initial concentration of 920 36 2019 85 mg m 3 and EBRT of 28 s In the experiment the BTF system ran stably and had no problem of reactor clogging 2013 The Authors Published by Elsevier B V Selection and or peer review under responsibility of Beijing Institute of Technology Keywords biotrickling filter chlorobenzene activated sludge elimination capacity 1 Introduction Chlorobenzenes CBs are widely used as solvents degreasers odorizers and intermediates in the synthesis of various pesticides and dyes 1 CBs have great potential harm for their strong toxicity damagement to the endocrine system of organisms stimulating effect on eye and nose but also for its teratogenicity carcinogenicity and mutagenicity effect 2 4 It was reported that about 1 5 million CBs were released to the air every year 5 And long term exposure to chlorobenzene contaminated environment did great harm to human physical and mental health 6 Therefore the control and treatment of chlorobenzenes deserved certain practical significance And biological treatment of chlorobenzene and other organic matter had attracted increasing attention at Cheng Ding Telfax 88168611 E mail address ycdingc Available online at 2013 The Authors Published by Elsevier B V Selection and peer review under responsibility of Beijing Institute of Technology 392 Bairen Yang et al Procedia Environmental Sciences 18 2013 391 396 home and abroad in recently Biotrickling filter was chosen because of the better control of reactor conditions including spray water and pH compared with traditional biofilters and bioscruber filters Several studies have proven good removal efficiency on volatile organic compounds such as H2S 7 NH3 8 2 chlorophenol 9 methanol 10 and other VOCs 11 Nevertheless until now there was little study published about biotrickling filter applied to the treatment of chlorobenzene gas The aim of study was to investigate the potential of biotrickling filter inoculated activated sludge to remove gaseous chlorobenzene and the effect of EBRT and inlet load on the performance of BTF in steady state were examined which can provide some guidance to further study on this system and industrial application 2 Materials and Methods 2 1 Experiment equipment The biotrickling filter was made of plexiglass with diameter of 10 cm and height of 120 cm and a packing material volume of 8 64 L The studied BTF has four segments which is presented in Fig 1 The BTF was operated in a countercurrent flow mode i e with the gas flowing upward and the recirculation liquid flowing downward The spray liquid was raised to the top of BTF and a water distributor was placed at the top of the column to enable liquid redistribution The chlorobenzene contaminated stream was introduced through the bottom of the column of the BTF The chlorobenzene inlet concentration was adjusted by rotameter though mixing with air supplied by an air compressor The chlorobenzene initial concentration was controlled in appropriate range by changing the flow of the two air path Experiments were carried out at laboratory room temperature in the range 17 28 and room pressure The superficial liquid velocity was 0 25 0 8 m3 h which corresponds to the empty bed retention time of 28 90 s And the inlet concentration was 648 9 2019 85 mg m 3 Buffer tank Chlorobenzene bottle Rotameter Gas sample port Biotrickling filter Water recirculation tank Packing sample port Air outlet Peristaltic pump Air compressor Fig 1 Schematic diagram of biotrickling filter 2 2 Materials The packing materials consisted of activated carbon fibers and multi surface hollow balls And the sludge was taken from aeration tank of a wastewater treatment plant in Yancheng Jiangsu province And 393 Bairen Yang et al Procedia Environmental Sciences 18 2013 391 396 the components of spray liquid were given in reference 12 2 3 Analytical method Concentration of CB was determined by capillary gas chromatography PerkinElmer Clarus with a flame ionization detector fitted and an Elite 5 capillary column 30 m length 0 25 mm diameter Samples were analyzed at a 1 5 mL min 1 total nitrogen flow rate and no split injection with the sampling volume of 500 The hydrogen flow rate was 45 mL min 1 the air flow rate was 450 mL min with the injection and detector temperatures were 200 and 250 respectively Oven temperature was increased at a rate of 10 min from 70 to a final temperature of 110 And the mixed liquid suspended solids MLSS and mixed liquor volatile suspended solids MLVSS were determined according to the standard methods 13 3 Results and Discussion 3 1 Enrichment of inoculum The raw sludge was washed for several times and then sludge supernatant and deposit were removed then adding water to form activated sludge mixed liquor Glucose and other nutrient solution 12 were added to the mixed liquor each day and stop 1 h of aeration meanwhile the sludge supernatant was wiped off aim to remove the intermediate products At last complement water to maintain constant volume of mixed liquid As shown in Fig 2 along with the increase of cultivation time the concentration of MLSS and MLVSS presented an upward tendency it showed that the sludge concentration increased gradually While the MLSS MLVSS varied from raw sludge of 0 54 to 0 62 after 10 d of culturation indicated that the biomass also increased in the process of sludge cultivation 0246810 4 5 6 7 8 9 10 Concentration g L Time d MLSS MLVSS Fig 2 Changes of MLSS and MLVSS during cultivation 3 2 Adaption to chlorobenzene degradation By gradually reducing the glucose content and increasing the chlorobenzene for directional domestication eventually chlorobenzene was used to replace glucose as the sole source of carbon for microorganisms growth Other nutrient solution was unchanged 394 Bairen Yang et al Procedia Environmental Sciences 18 2013 391 396 As shown in Fig 3 the concentrations of MLSS and MLVSS suddenly dropped at the start of acclimationwhich indicated that the worse tolerance nature on chlorobenzene Furthermore although the concentrations of MLSS and MLVSS also dropped down the MLSS MLVSS increased persistently the maximum value can reach 0 81 The result showed that the biomass in the sludge was an improvement more and more microorganism also can degrade chlorobenzene 1216202428323640 5 10 15 20 25 MLSS MLVSS Concentration g L 1 Time d 0 2 0 4 0 6 0 8 1 0 MLSS MLVSS MLSS MLVSS Fig 3 Changes of MLSS and MLVSS during cultivation 3 3 Effect of EBRT on the removal efficiency of the biotrickling filter Empty bed retention time is one of the key control parameters in the system running if the EBRT was too short the mass transfer between microorganisms and packing was inadequate On the other hand EBRET was too long which went against the efficiency of biotrickling filter So the study of the Fig 1 investigated the performance of the system after operating 50 d with the conditions of chlorobenzene gas concentration of about 1200 mg m 3 and EBRT of 28 s 45 s 75 s 90 s As shown in Fig 4 a stable behavior of the BTF was observed Also the removal efficiency of chlorobenzene was all above 60 along with the increase of time the removal efficiency of chlorobenzene increased gradually and the system operated stably The maximum removal efficiency could be reached under the condition of chlorobenzene initial concentration of 878 53 1522 48 mg m 3 and the EBRT of 56 s while the average removal efficiency was 91 34 Nevertheless in contrast to EBRT of 45 s RE of chlorobenzene did not increase substantially therefore the optimum empty bed retention time was at 45 s during operation in the experiments 50556065707580 0 500 1000 1500 2000 2500 3000 3500 4000 Outlet concentration Inlet concentration Removal efficiency Time d Chlorobenzene concentration mg m 3 0 20 40 60 80 100 EBRT 28s Removal efficiency EBRT 90sEBRT 75sEBRT 45s Fig 4 Correlation of EBRT and chlorobenzene removal efficiency 395 Bairen Yang et al Procedia Environmental Sciences 18 2013 391 396 3 4 Relationship between inlet load and outlet load The experiment investigated the relationship between elimination capacity of chlorobenzene and inlet load under the conditions of chlorobenzene concentration of 648 90 2019 85 mg m 3 and the EBRT for 28 s 45 s 75 s 90 s The results from Fig 5 showed that the elimination capacity under different EBRT presented the same trend along with the increase of inlet load under conditions of test the EC protocol was linearity elevation along with the increasing inlet load The maximum elimination capacity of 154 32 g m 3 h was reached at 28 s of EBRT However with the EBRT reduction elimination capacity of chlorobenzene deviated from 100 removal curve more and more distantly it indicated that the RE decreased So the lower of inlet load the more degradation of chlorobenzene was complete 20406080100120140160180200 20 40 60 80 100 120 140 160 180 EBRT 90s EBRT 75s EBRT 45s EBRT 28s 100 removal Elimination capacity g m 3 h 1 Inlet load g m 3 h 1 Fig 5 Correlation of elimination capacity and inlet load 4 Conclusions Cultivated and acclimated activated sludge was inoculated to biotrickling filter for degradation of chlorobenzene contamined gas In the experiment The BTF could start up successfully operate stably and have no problem of reactor clogging Trial results highlighted the effectiveness of the BTF system on degradation of gaseous chlorobenzene the maximum removal efficiency was reached under the EBRT of 90 s and the initial chlorobenzene concentration of 878 53 1522 48 mg m 3 while the average RE could reach 97 3 And 45 s was proven optimal EBRT Furthermore the maximum elimination capacity of 154 32 g m 3 h 1 was reached under the EBRT of 28 s and the initial chlorobenzene concentration of 920 36 2019 85 mg m 3 Acknowledgements This work was financially supported by National Innovation Program of Science and Technology 09C26213203714 research fund of Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province AE201119 and Qinglan Project of Science 1995 61 677 680 2 Alberici RM Jardim WF Photocatalytic destruction of VOCs in the gas phase using titanium dioxide Appl Catal B Environl 1997 14 55 68 3 Tsoukleris DS Maggos T Vassilakos C Falaras P Photocatalytic degradation of volatile organics on TiO2 embedded glass spherules Catal Today 2007 129 96 101 4 Jo WK Park JH Chun HD Photocatalytic destruction of VOCs for in vehicle air cleaning J of Photochem and Photobio A Chem 2002 148 109 119 5 Wcctman DF Volatile o