Anaerobic Wastewater Treatment from Finnish Forest Industry : VFA Analysis - The acidic wastewater effect on vola-tile fatty acids concentration
Li, Xingrong (2017)
Li, Xingrong
Savonia-ammattikorkeakoulu
2017
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-2017061213276
https://urn.fi/URN:NBN:fi:amk-2017061213276
Tiivistelmä
METVI, the efficient waste water pre-treatment project for forest industry wastewater is to strengthen the wastewater treatment process of paper mills. It is to reduce organic load in wastewater by more cost-effectively and significantly and improve the energy efficiency of the process.
Influent is the wastewater from Finnish forest industry. Recycled plant wastewater and part of debarking plant wastewater (very acidic one) is operated and added in the influent. These two types of wastewater are rich in COD. The measurement of volatile fatty acids is the key to the experiment.
In this study, the samples from influent, reactor 1, reactor 2, and effluent was done monitoring analyses by the anaerobic wastewater treatment: VFA analysis method. The ultimate aim of it is to reduce sludge management and recover energy in the form of biogas. The direct purpose is not only to investigate how different ratios of recycled plant wastewater and debarking plant wastewater influences the activity of biogas process, but also to evaluate the methanogenic bacteria from point the view of how the acidic wastewater effect of water volatile fatty acids concen-tration.
As a result of this, experiments show that with the increasing of debarking plant wastewater, acetic acid propionic acid, ethanol, butanediol and other organic matter also increased. The energy and carbon sources of methanogenic bacteria increased, the production of methane increased. This is an advantage of increasing the proportion of de-barking plant wastewater. At the same time, if the ratios of debarking plant wastewater is increased too much, the pH of the influent would reduced too much. The balance of the original bacteria would be destroyed. If an imbal-ance occurs, the amount of volatile fatty acids produced by acid bacteria would increased. Increasing VFA would cause pH decreases to a harmfully low level. This may weaken the activity of methanogens and may completely stop the production process. Because the optimum pH range for methanogens is between 6.8 and 7.2 (Cioabla, Ionel, Dumitrel and Popescu, 2012).
Influent is the wastewater from Finnish forest industry. Recycled plant wastewater and part of debarking plant wastewater (very acidic one) is operated and added in the influent. These two types of wastewater are rich in COD. The measurement of volatile fatty acids is the key to the experiment.
In this study, the samples from influent, reactor 1, reactor 2, and effluent was done monitoring analyses by the anaerobic wastewater treatment: VFA analysis method. The ultimate aim of it is to reduce sludge management and recover energy in the form of biogas. The direct purpose is not only to investigate how different ratios of recycled plant wastewater and debarking plant wastewater influences the activity of biogas process, but also to evaluate the methanogenic bacteria from point the view of how the acidic wastewater effect of water volatile fatty acids concen-tration.
As a result of this, experiments show that with the increasing of debarking plant wastewater, acetic acid propionic acid, ethanol, butanediol and other organic matter also increased. The energy and carbon sources of methanogenic bacteria increased, the production of methane increased. This is an advantage of increasing the proportion of de-barking plant wastewater. At the same time, if the ratios of debarking plant wastewater is increased too much, the pH of the influent would reduced too much. The balance of the original bacteria would be destroyed. If an imbal-ance occurs, the amount of volatile fatty acids produced by acid bacteria would increased. Increasing VFA would cause pH decreases to a harmfully low level. This may weaken the activity of methanogens and may completely stop the production process. Because the optimum pH range for methanogens is between 6.8 and 7.2 (Cioabla, Ionel, Dumitrel and Popescu, 2012).