Advanced

Biological removal of chlorinated organic compounds from kraft bleaching plant effluent

Yu, Peijie (1996)
Abstract (Swedish)
Popular Abstract in Swedish

Vid blekning av pappersmassa använd i många fall klorinnehållander blekkemikalier. Detta resulterar bildandet av olika klororganiska föreningar som hamnar i avloppsvattnet. Många klororganiska föreningar är giftiga och skadliga för miljön. För att minska utsläppen av dessa föreningar kan avloppsvattnet renas innan det släpps ut. I detta doktorsarbetet har nedbrytningen av klororganiska föreningar i blekeriavloppsvatten med hjälp av mikroorganismer studerats med syfte att förbättra möjligheterna att biologiskt rena denna typ av avloppsvatten.



En bakterie med förmåga att bryta ned triklorättiksyra, en av de klororganiska föreningar som förekommer i högst halt i... (More)
Popular Abstract in Swedish

Vid blekning av pappersmassa använd i många fall klorinnehållander blekkemikalier. Detta resulterar bildandet av olika klororganiska föreningar som hamnar i avloppsvattnet. Många klororganiska föreningar är giftiga och skadliga för miljön. För att minska utsläppen av dessa föreningar kan avloppsvattnet renas innan det släpps ut. I detta doktorsarbetet har nedbrytningen av klororganiska föreningar i blekeriavloppsvatten med hjälp av mikroorganismer studerats med syfte att förbättra möjligheterna att biologiskt rena denna typ av avloppsvatten.



En bakterie med förmåga att bryta ned triklorättiksyra, en av de klororganiska föreningar som förekommer i högst halt i blekeriavloppsvatten, isolerades och karatäriserades. Denna bakterie och en annan bakterie, med förmåga att bryta ned monoklorättiksyra och diklorättiksyra, användes i en studie av inverkan av kloreringsgraden hos organiska föreningar på förmågan hos aeroba bakterier att tillväxa genom att bryta ned dessa föreningar. Försöken visade att antalet kloratomer på den organiska molekylen har stark inverkan på både tillväxthastighet och tillväxtutbyte hos de bakterier som bryter ned ämnet i fråga. Ju högre kloreringsgrad hos föreningen desto lägre tillväxthastghet och utbyte.



I ett annat laboratorieförsök studerades mojligheten att genom en syrefri (anaerob) behandling av blekeriavloppsvatten avlägsna olika klorerade föreningar. Den anaeroba reningen visade sig därvid avlägsna ett flertal klororganiska föreningar som anses svårnedbrytbara i konventionella, luftade anläggningar. Den anaeroba reningen påverkades dock negativt av giftiga, oidentifierade föreningar i blekeriavloppsvattnet. Dessa föreningar befanns vara små molekyler med ursprung i blekeriets klorsteg.



Betydelsen av icke biologiska, spontana kemiska dekloreringsreaktioner på nedbrytningen av klororganiska föreningar i biologiska reningsverk studerades. Dessa reaktioner befanns ha endast en liten betydelse vid normala driftsförhållanden för biologisk rening (pH 7, 37°C). Vid förhöjda temperaturer och pH-värden accelererades dock den kemiska dekloreringen och vid pH 9 och 60°C var den icke biologiska dekloreringen av det klororganiska materialet i blekeriavloppsvatten av samma storlek som den biologiska dekloreringen vid pH 7 och 37°C. (Less)
Abstract
The microbial decomposition of chlorinated organic compounds in kraft bleaching plant effluent (KBPE) was studied. An aerobic bacterium, Strain TCA1, able to grow on trichloroacetic acid as the sole source of energy and carbon was isolated and characterized. Cultivations of Strain TCA1 and another bacterium, Strain DCA1, on acetic acid and its chlorinated analogues mono-, di-, and trichloroacetic acid showed that the growth rate and yield of the bacteria decreased considerably with an increased chlorine substitution of the substrate. This could be fully explained by the decreased energy content of the compounds following an increased degree of chlorine substitution. Anaerobic treatment of KBPE in a continuous laboratory scale reactor... (More)
The microbial decomposition of chlorinated organic compounds in kraft bleaching plant effluent (KBPE) was studied. An aerobic bacterium, Strain TCA1, able to grow on trichloroacetic acid as the sole source of energy and carbon was isolated and characterized. Cultivations of Strain TCA1 and another bacterium, Strain DCA1, on acetic acid and its chlorinated analogues mono-, di-, and trichloroacetic acid showed that the growth rate and yield of the bacteria decreased considerably with an increased chlorine substitution of the substrate. This could be fully explained by the decreased energy content of the compounds following an increased degree of chlorine substitution. Anaerobic treatment of KBPE in a continuous laboratory scale reactor showed this treatment to effectively remove a number of chloroorganic compounds. However, the effluent was found to be inhibitory to the methanogenic microflora. The toxicity was found to derive from compounds of a low molecular mass originating from the acidic part-stream of the KBPE. A comparison of different biological processes for the treatment of KBPE showed a sequential anaerobic/aerobic treatment to be the best alternative. This process combined the high dechlorination of chloroorganic compounds and removal of chlorate in the anaerobic process with the efficient removal of organic matter in the aerobic system. Studies of the importance of abiotic dechlorination reactions in biological treatment processes showed these reactions to be rather insignificant under normal biological operating conditions (pH 7, 37°C) while they were considerably speeded up at higher temperatures and pH values (thermo-alkaline treatment). At pH 8-9 and 60°C, the abiotic dechlorination was almost as efficient as the biological dechlorination. Combining thermo-alkaline and biological treatment resulted in a somewhat greater removal of chloroorganic compounds than was obtained when the two processes operated separately. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Svensson, Bo
publishing date
type
Thesis
publication status
published
subject
keywords
Thermo-alkaline, Aerobic, Anaerobic, Trichloroacetic acid, Kraft bleaching plant effluent, Biological wastewater treatment, Chloroorganic compounds, Biotechnology, Bioteknik
pages
56 pages
publisher
Department of Biotechnology, Lund University
defense location
Lecture Hall B, Chemical Center, Lund University, Lund
defense date
1996-06-06 13:15
external identifiers
  • other:ISRN: LUTKDH/TKBT-96/1029-SE
language
English
LU publication?
no
id
2bce35c2-6700-47e7-9b04-8ebb3dc591be (old id 28577)
date added to LUP
2007-06-15 09:13:55
date last changed
2016-09-19 08:45:01
@phdthesis{2bce35c2-6700-47e7-9b04-8ebb3dc591be,
  abstract     = {The microbial decomposition of chlorinated organic compounds in kraft bleaching plant effluent (KBPE) was studied. An aerobic bacterium, Strain TCA1, able to grow on trichloroacetic acid as the sole source of energy and carbon was isolated and characterized. Cultivations of Strain TCA1 and another bacterium, Strain DCA1, on acetic acid and its chlorinated analogues mono-, di-, and trichloroacetic acid showed that the growth rate and yield of the bacteria decreased considerably with an increased chlorine substitution of the substrate. This could be fully explained by the decreased energy content of the compounds following an increased degree of chlorine substitution. Anaerobic treatment of KBPE in a continuous laboratory scale reactor showed this treatment to effectively remove a number of chloroorganic compounds. However, the effluent was found to be inhibitory to the methanogenic microflora. The toxicity was found to derive from compounds of a low molecular mass originating from the acidic part-stream of the KBPE. A comparison of different biological processes for the treatment of KBPE showed a sequential anaerobic/aerobic treatment to be the best alternative. This process combined the high dechlorination of chloroorganic compounds and removal of chlorate in the anaerobic process with the efficient removal of organic matter in the aerobic system. Studies of the importance of abiotic dechlorination reactions in biological treatment processes showed these reactions to be rather insignificant under normal biological operating conditions (pH 7, 37°C) while they were considerably speeded up at higher temperatures and pH values (thermo-alkaline treatment). At pH 8-9 and 60°C, the abiotic dechlorination was almost as efficient as the biological dechlorination. Combining thermo-alkaline and biological treatment resulted in a somewhat greater removal of chloroorganic compounds than was obtained when the two processes operated separately.},
  author       = {Yu, Peijie},
  keyword      = {Thermo-alkaline,Aerobic,Anaerobic,Trichloroacetic acid,Kraft bleaching plant effluent,Biological wastewater treatment,Chloroorganic compounds,Biotechnology,Bioteknik},
  language     = {eng},
  pages        = {56},
  publisher    = {Department of Biotechnology, Lund University},
  title        = {Biological removal of chlorinated organic compounds from kraft bleaching plant effluent},
  year         = {1996},
}