Compounds interaction on the biodegradation of butanol mixture in a biofilter.

Compounds interaction on the biodegradation of n-butanol and sec-butanol mixture in a composite bead biofilter was investigated. The biodegradation rate of compounds in the exponential growth phase and stationary phase for the single compound and two compounds mixing systems was determined. The microbial growth rate and biochemical reaction rate of two compounds decreased with increasing compound inlet concentration for the single compound system. The microbial metabolic activity of sec-butanol biodegraded in the microbial growth process and biochemical reaction process was inhibited as n-butanol was introduced. This inhibitive effect was more pronounced at higher n-butanol inlet concentration and lower sec-butanol inlet concentration for the two compounds mixing system.

Compounds interaction on the biodegradation of acetone and methyl ethyl ketone mixture in a composite bead biofilter.

Compounds interaction on the biodegradation of acetone and methyl ethyl ketone (MEK) mixture in a composite bead biofilter was investigated. The biodegradation rate of two compounds in the exponential growth phase and stationary phase for the single compound and two compounds mixing systems was determined. The microbial growth rate and biochemical reaction rate of biodegraded two compounds was inhibited at higher compound inlet concentration for the single compound system. The microbial metabolic activity of biodegraded acetone in the microbial growth process and biochemical reaction process was inhibited by introducing MEK and was more pronounced at higher MEK inlet concentration and lower acetone inlet concentration for the two compounds mixing system. The maximum elimination capacity of acetone and MEK for the single compound system was smaller and greater than those for the two compounds mixing system, respectively.

Biofiltration of ethyl acetate and amyl acetate using a composite bead biofilter.

Biodegradation kinetic behaviors of ethyl acetate and amyl acetate in a composite bead biofilter were investigated. The composite bead was the spherical PVA/peat/KNO3/GAC composite bead which was prepared in our previous works. Both microbial growth rate and biochemical reaction rate were inhibited at higher inlet concentration. For the microbial growth process, the microbial growth rate of ethyl acetate was greater than that of amyl acetate in the inlet concentration range of 100-400ppm. The degree of inhibitive effect was almost the same for ethyl acetate and amyl acetate in this concentration range. The half-saturation constant Ks values of ethyl acetate and amyl acetate were 16.26 and 12.65ppm, respectively. The maximum reaction rate Vm values of ethyl acetate and amyl acetate were 4.08 and 3.53gCh(-1)kg(-1) packed material, respectively. Zero-order kinetic with the diffusion limitation could be regarded as the most adequate biochemical reaction model. For the biochemical reaction process, the biochemical reaction rate of ethyl acetate was greater than that of amyl acetate in the inlet concentration range of 100-400ppm. The inhibitive effect for ethyl acetate was more pronounced than that for AA in this concentration range. The maximum elimination capacity of ethyl acetate and amyl acetate were 82.3 and 37.93gCh(-1)m(-3) bed volume, respectively. Ethyl acetate degraded by microbial was easier than amyl acetate did.

Kinetic characteristics of n-butyl alcohol and iso-butyl alcohol in a composite bead air biofilter.

Kinetic characteristics of n-butyl alcohol and iso-butyl alcohol in a composite bead biofilter were investigated. The microbial growth rate of n-butyl alcohol was greater than that of iso-butyl alcohol in the average inlet concentration range of 50-300 ppm. The microbial growth rate was inhibited at higher inlet concentration, and the inhibitive effect in the concentration range of 50-150 ppm was more pronounced than that in the concentration range of 150-300 ppm. The degree of inhibitive effect for n-butyl alcohol was more sensitive than that for iso-butyl alcohol in the concentration range of 50-150 ppm. The zero-order kinetic with the diffusion rate limitation could be regarded as the most adequate biochemical reaction model. The biodegradation rate of n-butyl alcohol was greater than that of iso-butyl alcohol in the average inlet concentration range of 50-300 ppm. The biochemical reaction rate was also inhibited at higher inlet concentration, and the inhibitive effect for iso-butyl alcohol was more pronounced than that for n-butyl alcohol. The factor of the chemical structure of compound was more predominant in the microbial growth and biochemical reaction processes. The maximum elimination capacity of n-butyl alcohol and iso-butyl alcohol were 55.7 and 34.8 g C h(-1)m(-3) bed volume, respectively. The compound with no side group in the main chain would be easier biodegraded by the microbial.

Biofiltration of ketone compounds by a composite bead biofilter.

In this study, the biochemical kinetic behaviors of ketone compounds in a composite bead biofilter were investigated. Both microbial growth rate kg and biochemical reaction rate kd would be inhibited at higher average inlet concentration. For the microbial growth process, the inhibitive effect was the least pronounced for acetone and the order of kg value was MEK>MIPK>acetone in the average inlet concentration range of 100-150 ppm. The degree of inhibitive effect was almost the same for three ketone compounds and the order of kg value was acetone>MEK>MIPK in the average inlet concentration range of 200-300 ppm. The values of half-saturation constant Ks for acetone, MEK and MIPK were 26.80, 21.56 and 22.96 ppm, respectively. The values of maximum reaction rate Vm for acetone, MEK and MIPK were 8.55, 9.06 and 7.55 g-C/h-kg packed material, respectively. The zero-order kinetic with the diffusion rate limitation could be regarded as the most adequate biochemical reaction model. For the biochemical reaction process, the inhibitive effect was the most pronounced for MEK and the order of kd value was MEK>acetone>MIPK in the average inlet concentration range of 100-150 ppm. The degree of inhibitive effect was MIPK>MEK>acetone and the order of kd value was acetone>MEK>MIPK in the average inlet concentration range of 200-300 ppm. The maximum elimination capacity of acetone, MEK and MIPK were 0.157, 0.127 and 0.101 g-C/h-kg packed material.

Biochemical kinetic behaviors between n-butyl acetate and composite bead in biofilter.

In this study, the kinetic behaviors between n-butyl acetate and composite bead were investigated. Both microbial growth rate and biochemical reaction rate would be inhibited with increasing average inlet concentration. The order of the inhibitive effect, which resulted from increased average inlet concentration for four operation temperatures, was 30>35>40>25 degrees C. Both microbial growth rate and biochemical reaction rate would be enhanced and inhibited with increasing operation temperature in the operation temperature ranges of 25 to 30 and 30 to 40 degrees C, respectively. The enhancing and inhibitive effects resulting from increased operation temperature were the most pronounced at the average inlet concentration of 200 ppm. The values of maximum reaction rate V (m) and half-saturation constant K (s) ranged from 0.011 to 0.047 g C h(-1) kg(-1) packed material and from 19.30 to 62.40 ppm, respectively. The zero-order kinetic with the diffusion rate limitation could be regarded as the most adequate biochemical reaction kinetic model. The values of maximum elimination capacity ranged from 0.51 to 0.20 g C h(-1) kg(-1) packed material, and the optimal maximum elimination capacity of biofilter occurred at the operation temperature of 30 degrees C.

Kinetic behaviors between acetone and composite bead in biofilter.

In this study, the kinetic behaviors between acetone and composite bead were investigated. The microbial growth rate decreased with increasing average inlet concentration and increased with increasing operation temperature at average inlet concentration ranging from 50 to 300 ppm and operation temperature ranging from 30 to 40 degrees C. The microbial growth rate would be inhibited with increasing average inlet concentration, and the inhibitive effect was more pronounced at higher operation temperature. The microbial growth rate would be enhanced with increasing operation temperature, and the enhancing effect was more pronounced at higher average inlet concentration. The values of maximum reaction rate Vm and half-saturation constant Ks ranged from 0.04 to 0.05 g-C/h-kg packing material and from 37.19 to 42.77 ppm, respectively. The biochemical reaction model could be regarded as the zero-order kinetic with the diffusion rate limitation. The biochemical reaction rate decreased with increasing average inlet concentration and increased with increasing operation temperature. The biochemical reaction rate would be inhibited with increasing average inlet concentration, and the inhibitive effect was more pronounced at lower operation temperature. The biochemical reaction rate would be enhanced with increasing the operation temperature, and the enhancing effect was more pronounced at higher average inlet concentration. The maximum elimination capacity of biofilter increased with increasing operation temperature. The values of critical and maximum elimination capacity ranged from 0.07 to 0.15 and from 0.13 to 0.16 g-C/h-kg packing material, respectively.

A process to prepare a synthetic filter material containing nutrients for biofiltration.

In this study, an optimal process to prepare a synthetic filter material (poly(vinyl alcohol) (PVA)/peat/KNO(3) composite bead) containing nutrients was developed for biofiltration. The optimal preparing condition was that each of the peat and PVA aqueous solutions contains 6.4 g KNO(3) and the nitrogen content in the boric and phosphate aqueous solutions must retain higher than 3.94 and 1.52 g N/l, respectively. The equilibrium amount of water-soluble nitrogen dissolved out of the prepared composite bead was between 7.95 and 8.21mg N/g dry solid. The path of water-soluble nitrogen dissolving out of the A-type bead was the water-soluble nitrogen dispersed in the peat phase initially diffused into the outer PVA phase and then it diffused out of the bead surface. And the path of water-soluble nitrogen dissolving out of the H-type bead was the water-soluble nitrogen dispersed in both the peat and PVA phases simultaneously diffused into the outer PVA phase and out of the bead surface, respectively. The microbial growth rate k(g) of the H-type composite bead was higher than that of the A-type composite bead approximately 1.09-1.58 times, and its value was between 0.100 and 0.417 day(-1) as the composite bead was immersed in 0-0.896 M KNO(3) solution. The maximum value of k(g) appeared at the composite bead immersed in 0.384 M KNO(3) solution and was higher than that of the compost by a factor approximately 1.49. The percentage of removed volatile organic compounds (VOCs) remained at more than 98% during the biofilter operating 230 days as the composite bead was immersed in KNO(3) aqueous solution before packing. This composite bed was without the further addition of nutrients during this operating period. It was proved that this composite bead was superior to the compost as a filter material.

The mechanism of nutrients dissolved out of a synthetic composite bead filter material in a biofilter.

In this study, an optimal process to prepare a synthetic material having nutrient (PVA/peat/KNO(3) composite bead) is developed. The equilibrium water-soluble nitrogen content in the composite bead prepared by this process is 8.25-10.06 mg N/g dry solid. The mass-transport process for the water-soluble nitrogen dissolved out of the composite bead was also investigated. The dissolved out process occurs in two stages: external mass transport occurs in the early stage and the intraparticle diffusion process occurs in the long-term stage. The rate of water-soluble nitrogen dissolved out in both stages is concentration dependent. The path of nitrogen dissolved out is that the nitrogen dispersed in the peat and PVA phases simultaneously diffused into the outer PVA phase and out of the bead surface. The moisture holding capacity of the composite bead bed is better than the compost bed. The percentage of removed volatile organic compounds (VOCs) can remain at levels higher than 99% for a longer time (about 230 d) as the composite bead immersed in a KNO(3) aqueous solution before packing with an optimal concentration of KNO(3) aqueous solution of 0.384 M. The rate of nitrogen dissolved out in the intraparticle diffusion process could be used as an index to predict the microbial growth rate in the biofilter.