An explosion in a petrochemical plant in Jilin in the northeast of China on 13 November 13 2005 was responsible for the discharge of large quantities of benzene and nitrobenzene into Songhua River. This endangered the water supply of Harbin city and influenced the daily life for millions of people. The dispersion-advection equation was solved analytically and numerically and used to simulate the concentration of benzene and nitrobenzene in the Songhua River after the accident. Both solutions gave practically identical results. The main elimination process for both compounds was volatilization. The model results are quite close to the results obtained by measurements at monitoring stations. Arrival time of the pollutant wave, peak concentrations and end of the pollutant wave at Harbin and along the river were predicted successfully. The peak concentrations of nitrobenzene at Harbin were more than 30 times above the permissible limits for drinking water. This paper describes the distribution of benzene and nitrobenzene in the Songhua River after the accident in Jilin

Fu, Huijin

Fu, Wenjing

Skøtt, Karen

Yang, Min

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Downloaded from orbit.dtu.dk on: Dec 17, 2017Modeling the Spill in the Songhua River after the Explosion in the Petrochemical Plantin JilinFu, Wenjing; Fu, Huijin; Skøtt, Karen; Yang, MinPublished in:Environmental science and pollution research internationalLink to article, DOI:10.1065/espr2007.11.457Publication date:2008Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Fu, W., Fu, H., Skøtt, K., & Yang, M. (2008). Modeling the Spill in the Songhua River after the Explosion in thePetrochemical Plant in Jilin. Environmental science and pollution research international, 15(3), 178-181. DOI:10.1065/espr2007.11.457Explosion in the Petrochemical Plant in Jilin Subject Area 2.2178© Springer-Verlag 2008Env Sci Pollut Res 15 (3) 178 – 181 (2008)Area 2.2 • Modeling of Chemicals in WaterResearch ArticleModeling the Spill in the Songhua River after the Explosion in thePetrochemical Plant in Jilin*Wenjing Fu**, Huijin Fu, Karen Skøtt and Min YangInstitute of Environment & Resources DTU, Technical University of Denmark, 2800 Kongens Lyngby, Denmark**Corresponding author  (wenjingfu@gmail.com)Here, dispersion-advection models have been used to simu-late and interpret the transport of the pollution wave in theSonghua River downstream of the explosion point. The re-sults were compared to the measured concentrations in theriver and to legal standards.1 Methods1.1 Model ImplementationThe downstream transport of chemicals in rivers after pulseemissions (accidents) is described by the dispersion-advec-tion equation (Trapp & Matthies 1998):CxuCxCDtC λ−∂∂−∂∂∂=∂∂ )(2whereC is the concentration in the river water [mg m–3],t is the flow time [s], D is the dispersion coefficient [m2 s–1],u is the flow velocity [m s–1] andλ is a first-order loss rate.DOI: http://dx.doi.org/10.1065/espr2007.11.457Please cite this paper as: Fu W, Fu H, Skøtt K, Yang M(2008): Modeling the Spill in the Songhua River after the Ex-plosion in the Petrochemical Plant in Jilin. Env Sci Pollut Res15 (3) 178–181AbstractAn explosion in a petrochemical plant in Jilin in the northeastof China on 13 November 2005 was responsible for the dis-charge of large quantities of benzene and nitrobenzene intoSonghua River. This endangered the water supply of Harbincity and influenced the daily life for millions of people. Thedispersion-advection equation was solved analytically and nu-merically and used to simulate the concentration of benzeneand nitrobenzene in the Songhua River after the accident. Bothsolutions gave practically identical results. The main elimina-tion process for both compounds was volatilization. The modelresults are quite close to the results obtained by measurementsat monitoring stations. Arrival time of the pollutant wave, peakconcentrations and end of the pollutant wave at Harbin andalong the river were predicted successfully. The peak concentra-tions of nitrobenzene at Harbin were more than 30 times abovethe permissible limits for drinking water.Keywords: Accidents; benzene; chemical industry; China; Har-bin; Jilin; model; nitrobenzene; petrochemical plant; SonghuaRiver; spillsESS-Submission-Editor: Stefan Trapp (stt@er.dtu.dk)IntroductionOn the 13 November 2005, at 13:00 pm, an explosion oc-curred at the Jilin Chemical Industrial Co., a subsidiary ofthe China National Petroleum Corporation Plant, locatedin Jilin Province. Five people died and more than 70 otherswere injured (Tan 2005). Approximately 100 tons of a mix-ture of benzene, nitrobenzene and other toxic compoundswere spilled into the Songhua River (UNEP 2005). Harbin,which is the capital of the Heilongjiang Province, is locatedapproximately 500 km downstream from the explosion scene(Fig. 1). The pollution front was expected to arrive at SifangTai, one of Harbin's monitoring points, at 5 am on Novem-ber 24, 2005, and since Songhua River is responsible for90% of the water supply to Harbin, the water supply wascut off from midnight on November 23, 2005.To our knowledge, except for a UNEP report (UNEP 2005),no scientific study of this accident has been published so far.  Fig. 1: Map of Songhua River (China) from the explosion scene to Harbin.The arrows indicate the flow direction of the river waterSubject Area 2.2 Explosion in the Petrochemical Plant in JilinEnv Sci Pollut Res 15 (3) 2008 179Both analytical (IKSR 1991, Brüggemann et al. 1991) andnumerical solutions (Reichert & Wanner 1987) of this equa-tion have been used to simulate chemical spills in rivers. Abasic analytical solution, assuming constant conditions andpulse input, is( ) ( )0 24,4x uttDtmAC x t e eDtλπ−−= ⋅ ⋅wherem0 is the emitted mass of chemical [kg],A is the river cross-sectional area [m2] andx is the distance from release [m].An easy numerical solution of the dispersion-advection equa-tion uses the explicit finite-difference method. The numeri-cal dispersion is made equal to the real dispersion in theriver by appropriate selection of time and space grid underconsideration of the Courant-criterion (Trapp & Matthies1998). Subsequently, the dispersion term can be omitted fromthe equations. The resulting iteration scheme is( ), 1 , , 1,i j i j i j i juC C C C t C txλ+ −= − ⋅ − ⋅ ∆ − ⋅ ⋅ ∆∆wherei is the step in x-direction, andj in t-direction.Numerical and analytical solution gave practically the sameresult. Below, only results obtained with the analytical solu-tion are shown.The elimination constant λ is the sum of all elimination pro-cesses. However, for benzene and nitrobenzene, sedimenta-tion, photo- and biodegradation were neglected due to thelow sorption coefficient Kd and the low temperature and lightof the river in winter. The loss from water was subsequentlyassumed to be due to volatilization of the compounds andcalculated with the two-film theory (Trapp & Harland 1995):gAWlV kKkh111+=λwhereV is the rate for loss via volatilization (1/time),kl is conductance of the liquid film [length/time],kg is conductance of the gaseous film [length/time],h is average river depth [m] andKAW is the partition coefficient air-water of the chemical.The regression equations of Southworth (1979) for rivers wereused to calculate the exchange velocities, for the liquid filmMhukl322351.0 673.0969.0 ×××= −    (m/h)whereM is the molar mass of the chemical andu is the flow velocity (m s–1).The conductance of the gaseous film was calculated as( )Muvkl1837.11 ×+=     (m/h)whereν is the wind speed (here: set to zero).1.2 DataThe input data for benzene and nitrobenzene are shown inTable 1. The released amounts of benzene and nitrobenzenewere fitted. The other parameters were taken from thewebsite of the HINC Heilongjiang Information Network ofChina (2006) and other sources.Parameter Symbol Value Units Reference Input of benzene m  7.5 tons fitted Input of nitrobenzene m 92.6 tons fitted Partition coefficient air-water of benzene KAW  0.23  Rippen (2006) Elimination rate of benzene λ 0.182 D–1 calculated Cross area of the river A 1,480 m2 HINC (2006) Width of the river W 370 m HINC (2006) Dispersion coefficient D 500  Typical value (Trapp & Matthies 1998) Flow velocity u 0.53 m s–1 estimated Molar mass of benzene M 78 g mol–1 Rippen (2006) Molar mass of nitrobenzene M 123.11 g mol–1 Rippen (2006) Partition coefficient air-water of nitrobenzene KAW 0.0029  Rippen (2006) Elimination rate of nitrobenzene λ  0.0318 D–1 calculated Water depth  h  4 M estimated Wind speed v 0 m s–1 assumption  Table 1: Input data used for the simulationsExplosion in the Petrochemical Plant in Jilin Subject Area 2.2180 Env Sci Pollut Res 15 (3) 2008The measured data of benzene were collected from the pub-lic report released by the Environmental Protection Bureauof Heilongjiang Province. These data were monitored bythe Heilongjiang Environmental Monitoring Centre and atthe Jiamusi Environmental Monitoring Station. The mea-sured data of nitrobenzene were collected from the UNEPexpert team report (UNEP 2005).2 Results and DiscussionBenzene. Fig. 2 shows the result of the analytical solutionfor the concentration of benzene at Harbin compared tothe measured data. The agreement is not completely unex-pected, since the input of benzene was fitted. However, alsothe shape of the curve and the peak arrival are in goodagreement. The river water concentration of benzene atHarbin is throughout below the Chinese permission levelof 0.01 mg/L (UNEP 2005).Nitrobenzene. The results for nitrobenzene are shown inFig. 3. Again, simulations and measurements are in goodagreement. A deviation is seen for the second measured con-centration (t = 10.5 d). This might indicate that dispersion,which drives the width of the peak, was overestimated. Therelease of nitrobenzene into the river was much higher thanthe release of benzene, and much higher concentrations weremeasured at Harbin. The guideline for nitrobenzene in drink-ing water in China is 0.017 mg/l, which was exceeded sig-nificantly at the time the pollution wave passed Harbin onNovember 23, 2005 (UNEP 2005). The peak concentrationwas 0.58 mg/l, which is about 33 times the permitted level.00.0050.018 10 12 14t (d)C (mg/L)  00.250.50.758 13t (d)C (mg/L)  00.10.20.30.40.50.60.70.80.914 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36time after release [days]Concentration [mg/l]   00.250.50.751Songyuan (286 km)Harbin (500 km)Mulan (705 km)Tonghe (775 km)Yilandalian (912 km)Pre-Jiamusi (1046 km)Jiamusi (1145 km)Fujin (1415 km)Concentration (mg/l)Modeled Measured  Fig. 2: Comparison of the calculated and the measured concentration ofbenzene in the Songhua River at Harbin after the accidentFig. 3: Comparison of the calculated and the measured concentration ofnitrobenzene in the Songhua River at Harbin after the accidentThe simulation of the concentration of nitrobenzene alongthe Songhua River versus time is shown in Fig. 4. The peakbroadens and the maximum concentrations decrease withdistance and flow time, due to dispersion. There is also adecrease of pollutant mass (represented by the area belowthe curve), which is due to volatilization of the chemicalfrom the river water into air. Nevertheless, the peak con-centration at the Fujin monitoring station 1415 km down-stream and 31 days after the accident is still 10 times abovethe permissible level of 0.017 mg/l for drinking water inChina. The comparison between measured and calculatedpeak concentration of nitrobenzene is shown in Fig. 5. Thesmall differences between calculated and measured concen-trations of nitrobenzene might be explained by the varia-tion of the width and depth of the river, which the modeldid not account for.3 ConclusionsThe concentrations of benzene and nitrobenzene in theSonghua River after the accident in Jilin could be success-fully calculated and interpreted using an analytical or a nu-Fig. 5: Comparison of predicted and measured peak concentration of ni-trobenzene along the Songhua RiverFig. 4: Concentration of nitrobenzene along the Songhua River estimatedwith the analytical model at the following monitoring stations: 1. Songyan(286 km); 2. Harbin (500 km); 3. Mulan (705 km); 4. Tonghe (775 km); 5.Yilandal (912 km); 6. Pre-Jiamus (1046 km); 7. Jiamus (1145 km); 8. Fujin(1415 km)Subject Area 2.2 Explosion in the Petrochemical Plant in JilinEnv Sci Pollut Res 15 (3) 2008 181merical solution of the one-dimensional dispersion-advec-tion equation. The simulations could predict the time ofarrival of the pollutant wave, the peak concentrations andthe end of the pollutant wave at Harbin and along the river.The model results and the measurements along the riverindicate that the contamination with benzene was less seri-ous than the contamination with nitrobenzene. This wasprobably due to the higher amount of nitrobenzene releasedduring the accident. According to the model simulations,the elimination in the river was mainly due to volatiliza-tion, while photolysis and biodegradation were low, due towinter conditions.Acknowledgements  This study was prepared as project work inthe course 12233 Water Pollution at the Technical University of Den-mark under supervision of the course coordinator Stefan Trapp. Wewant to thank our teacher for the interesting course and for help withthe manuscript.ReferencesBrüggemann R, Trapp S, Matthies M (1991): Behaviour assess-ment for a volatile chemical in the Rhine River. Environ ToxicolChem 10, 1097–1103HINC Heilongjiang Information Network of China (2006)http://www.hljxxw.gov.cn/sqgl/dxqh/t20051115_3204.htm, ac-cessed 21 Nov 2006IKSR Internationale Kommission zum Schutz des Rheins (1991):Rhine alarm model 2.0. Report-no. II-4 of the KHR, Koblenz,D (in German)Reichert P, Wanner O (1987): Simulation of a severe case of pol-lution of the Rhine River. Proceedings of the Twelfth Congressof the International Association of Hydraulic Research, Lau-sanne, Switzerland, Aug. 31–Sept. 4. Water Resources, Littleton,CO, pp 239–244Rippen G (2006): Handbuch Umweltchemikalien. ecomed, Lands-berg am Lech, GermanySouthworth GR (1979): The role of volatilization in removingpolycyclic aromatic hydrocarbons from aquatic environments.Bull Environ Contam Toxicol 21, 507–511Tan F (2005): Toxic threat watered down in Harbin. Asian Chemi-cal News 11 (517) 11Trapp S, Harland B (1995): Field test of volatilization models.Env Sci Pollut Res 2 (3) 164–169Trapp S, Matthies M (1998): Chemodynamics and environmen-tal modeling, Springer, Berlin, GermanyUNEP United Nations Environment Programme (2005): ChineseRiver Contamination Resulting from A Petrochemical Explo-sion and Toxic Spill. http://www.uneptie.org/pc/apell/disasters/china_harbin/info.htm and http://www.uneptie.org/pc/apell/di-sasters/china_harbin/unepmr.pdf, accessed 21 Nov 2006Received: May 3rd, 2007Accepted: November 7th, 2007OnlineFirst: December 7th, 2007http://www.uneptie.org/pc/apell/disasters/china_harbin/unepmr.pdfUnited Nations Environment Programme – The Songhua River SpillChina, December 2005: Field Mission Report1  Introduction1.1  Background to the spill1.2  Scope of the mission1.3  Mission team1.4  Meteorological conditions2  Observations and Discussions2.1  Description of the Songhua River Spill2.2  Coordination of response2.3  Emergency pollution monitoring2.4  Pollution control and mitigation measures2.5  Information and communication2.6  Medium and long term measures2.7  Cooperation and coordination with Russia in monitoring and response2.8  Limitations to the mission 143  Conclusions and RecommendationsAnnex 1. Itinerary of the UNEP Mission on Songhua River Chemical SpillAnnex 2. Fact sheet of Benzene, Nitrobenzene and AnilineAnnex 3 Key resource persons to the missionAnnex 4. UNEP Field Team

Modeling the Spill in the Songhua River after the Explosion in the Petrochemical Plant in Jilin

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Modeling the Spill in the Songhua River after the Explosion in the Petrochemical Plant in Jilin

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