management of material flows in waste disposal networks: a new approach for the economic and...

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With the efficient cooperation of both micro-organisms groups a reasonable wastewater purification procedure is designed first of all in areas with long sunshine duration. 006 Removal of Flame Retardants from Electronic Waste Materials Using Supercritical CO 2 -Extraction ThomasGamse RolfMarr Institut fu ¨ r Thermische Verfahrenstechnik und Umwelttechnik, TU Graz, Inffeldgasse 25, A-8010 Graz, Austria, fax: ++43 316 873 7472, E-mail: [email protected] Electronic waste materials contain flame retardants to protect the plastic material in case of fire. Especially these flame retardants cause problems during incineration because of forming dioxines. In the first step solubility measurements and calculations were per- formed for two mainly used flame retardants, for hexabromcyclo- dodecane (HBCD) and for tetrabrombisphenyl-A (TBBA). Differ- ent pressures (200, 300, 400 and 500 bar) and temperatures (25 C, 40 C, 60 C, 80 C and 100 C) were investigated and the ex- perimental solubility data were fitted by means of the Chrastil equation. Supercritical CO 2 -extraction experiments were carried out for the polymer polybuylenterephthalate (PBT) containing on one hand TBBA and on the other hand HBCD. With pure CO 2 extraction yields up to 100 % could be achieved at 500 bar and 100 C. Using CO 2 – modifier mixtures (methanol, isopropyl alcohol, toluene) reduces the necessary extraction pressure for complete separation to 200 bar. 007 Minimisation of Nitrogen Discharge for Small Size Wastewater Treatment Plants B.Chachuat N.Roche M.A.Latifi Laboratoire des Sciences du Ge ´nie Chimique, CNRS-ENSIC, B.P. 451, 1 rue Grandville, 54001 Nancy Cedex, France, Tel : ++ 33 3 83 17 52 34, Fax : ++ 33 3 83 17 53 26, E-mail addresses : {chachuat, roche, latifi}@ensic.inpl-nancy.fr The use of dynamic optimisation methods to provide optimal oper- ating strategies for small size wastewater treatment plants is inves- tigated. The optimisation objective is to determine the aeration pro- file (air-on and air-off periods) which minimise the concentration of total nitrogen that is discharged over a specified time horizon. Long term effects of the optimisation are considered; it is shown that appreciable reductions of total nitrogen residual concentration of about 30 % can be achieved with respect to usual operating modes, along with large reductions of aeration time. 008 Management of Material Flows in Waste Disposal Networks: A New Approach for the Economic and Ecological Combination of Logistics and Process Engineering JensNeugebauer Dr.HartmutPflaum Prof.Dr.HansFahlenkamp Fraunhofer-Institute for Environmental, Safety, and Energy Technology UMSICHT On the threshold of the new millennium, networking has already become an important part of our life. However, not only production networks but also waste disposal networks must be regarded to realise a sustainable closing of business cycles. Waste disposal net- works cannot be compared with the traditional production manage- ment mainly due to the underlying specific legislative regulations and different economic structures. This article presents the so- called “elementary processes” as one possible basis for the consis- tent aggregation of mass and energy flows in such networks. Each unit operation of a waste transport or treatment process is de- scribed by specific phenomena which are concentrated on the waste material flow. The transformation of given input into possi- ble output parameters in combination with characteristic indices for each elementary process finally lead to the economic and eco- logical optimisation of a given network. 009 The Reactivity of Soot Surfaces and Its Role in Aerosol Particle Formation SabineSeisel Go ¨tzGleitsmann ReinhardZellner Institute of Physical and Theoretical Chemistry University of Essen, Universita ¨tsstr. 5, D-45117 Essen, Germany, E-mail: [email protected] The uptake of HNO 3 and H 2 O on kerosene soot has been studied at 300 K using a Knudsen flow reactor. An uptake coefficient of c = 1.4·10 -4 for HNO 3 and c = 4.7·10 -4 for H 2 O has been determined. The results have been implemented together with water adsorp- tion isotherms into a model calculating contrail formation in the jet regime of a B-747 airliner. Depending on the ambient physical conditions the visibility of the contrail has been predicted to com- mence between 40 and 270 m behind the engine in good agreement with in-flight observations. 590 Environmental Engineering Chemie Ingenieur Technik (73) 6 I 2001

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Page 1: Management of Material Flows in Waste Disposal Networks: A New Approach for the Economic and Ecological Combination of Logistics and Process Engineering

With the efficient cooperation of both micro-organisms groups areasonable wastewater purification procedure is designed first ofall in areas with long sunshine duration.

006

Removal of Flame Retardants fromElectronic Waste Materials UsingSupercritical CO2-Extraction

T h o m a s G a m s e

R o l f M a r r

Institut fuÈ r Thermische Verfahrenstechnik und Umwelttechnik,TU Graz, Inffeldgasse 25, A-8010 Graz, Austria, fax: ++43 316 8737472, E-mail: [email protected]

Electronic waste materials contain flame retardants to protect theplastic material in case of fire. Especially these flame retardantscause problems during incineration because of forming dioxines.In the first step solubility measurements and calculations were per-formed for two mainly used flame retardants, for hexabromcyclo-dodecane (HBCD) and for tetrabrombisphenyl-A (TBBA). Differ-ent pressures (200, 300, 400 and 500 bar) and temperatures(25 �C, 40 �C, 60 �C, 80 �C and 100 �C) were investigated and the ex-perimental solubility data were fitted by means of the Chrastilequation. Supercritical CO2-extraction experiments were carriedout for the polymer polybuylenterephthalate (PBT) containingon one hand TBBA and on the other hand HBCD. With pureCO2 extraction yields up to 100% could be achieved at 500 barand 100 �C. Using CO2 ± modifier mixtures (methanol, isopropylalcohol, toluene) reduces the necessary extraction pressure forcomplete separation to 200 bar.

007

Minimisation of Nitrogen Discharge forSmall Size Wastewater TreatmentPlants

B . C h a c h u a t

N . R o c h e

M . A . L a t i f i

Laboratoire des Sciences du Ge nie Chimique, CNRS-ENSIC, B.P.451, 1 rue Grandville, 54001 Nancy Cedex, France, Tel : ++ 33 3 83 1752 34, Fax : ++ 33 3 83 17 53 26, E-mail addresses : {chachuat, roche,latifi}@ensic.inpl-nancy.fr

The use of dynamic optimisation methods to provide optimal oper-ating strategies for small size wastewater treatment plants is inves-tigated. The optimisation objective is to determine the aeration pro-file (air-on and air-off periods) which minimise the concentration oftotal nitrogen that is discharged over a specified time horizon. Longterm effects of the optimisation are considered; it is shown thatappreciable reductions of total nitrogen residual concentrationof about 30% can be achieved with respect to usual operatingmodes, along with large reductions of aeration time.

008

Management of Material Flows inWaste Disposal Networks:A New Approach for the Economic andEcological Combination of Logisticsand Process Engineering

J e n s N e u g e b a u e r

D r . H a r t m u t P f l a u m

P r o f . D r . H a n s F a h l e n k a m p

Fraunhofer-Institute for Environmental, Safety, and EnergyTechnology UMSICHT

On the threshold of the new millennium, networking has alreadybecome an important part of our life. However, not only productionnetworks but also waste disposal networks must be regarded torealise a sustainable closing of business cycles. Waste disposal net-works cannot be compared with the traditional production manage-ment mainly due to the underlying specific legislative regulationsand different economic structures. This article presents the so-called ªelementary processesº as one possible basis for the consis-tent aggregation of mass and energy flows in such networks. Eachunit operation of a waste transport or treatment process is de-scribed by specific phenomena which are concentrated on thewaste material flow. The transformation of given input into possi-ble output parameters in combination with characteristic indicesfor each elementary process finally lead to the economic and eco-logical optimisation of a given network.

009

The Reactivity of Soot Surfaces and ItsRole in Aerosol Particle Formation

S a b i n e S e i s e l

G oÈ t z G l e i t s m a n n

R e i n h a r d Z e l l n e r

Institute of Physical and Theoretical Chemistry University ofEssen, UniversitaÈ tsstr. 5, D-45117 Essen, Germany, E-mail:[email protected]

The uptake of HNO3 and H2O on kerosene soot has been studied at300 K using a Knudsen flow reactor. An uptake coefficient of c =1.4´10-4 for HNO3 and c = 4.7´10-4 for H2O has been determined.The results have been implemented together with water adsorp-tion isotherms into a model calculating contrail formation in thejet regime of a B-747 airliner. Depending on the ambient physicalconditions the visibility of the contrail has been predicted to com-mence between 40 and 270 m behind the engine in good agreementwith in-flight observations.

590 E n v i r o n m e n t a l E n g i n e e r i n gChemie Ingenieur Technik (73) 6 I 2001