WO2006126797A1

WO2006126797A1 - Hydrophilic and hydrophobic packing media of biofilter for treating mixed malodor gases

Info

Publication number: WO2006126797A1
Application number: PCT/KR2006/001848
Authority: WO
Inventors: Wook Jin Chung; Melvin M. Galera; Ariz Lorenzana; Alex Anonas; Enkhdul Tuuguu; Grace M. Nisola; Dong Min Shim; Ju Hyeon Ahn; Shin Jeong Park; Suk Il Son; Eun Mi Gwon; Nam Jong Yoo
Original assignee: Wook Jin Chung; Galera Melvin M; Ariz Lorenzana; Alex Anonas; Enkhdul Tuuguu; Nisola Grace M; Dong Min Shim; Ju Hyeon Ahn; Shin Jeong Park; Suk Il Son; Eun Mi Gwon
Priority date: 2005-05-23
Filing date: 2006-05-18
Publication date: 2006-11-30
Also published as: KR100665548B1; KR20060120971A

Abstract

The present invention relates to hydrophilic and hydrophobic packing media for bio-filters for the treatment of mixed malodorous gases. This invention relates to the hydrophilic and hydrophobic bio-filter with a new concept, where only the advantages of bio-filters of organic and inorganic media are applied. The hydrophilic and hydrophobic packing media for bio-filters for the treatment of mixed malodorous gases of this invention characterized in the media is composed of a mixture of organic and inorganic media in a certain ratio, where activated carbon, organic and inorganic binding agents are added to form beads. The hydrophilic and hydrophobic packing media for bio-filters for the treatment of mixed malodorous gases manufactured in the manner described above are ball-type, light-weight, hard in structure, excellent in porosity and water-holding capacity, and can contain additional nutrients and microbes. The packing media are a very useful invention since they have excellent physical features, provide nutrition, water and the culture environment required for the growth and activities of microbes, provide desirable features for the operation of bio-filters in terms of pressure loss and compaction, and have remarkable effects in removing hydrophilic and hydrophobic malodorous gases.

Description

[Specification]

HYDROPHILIC AND HYDROPHOBIC PACKING MEDIA OF BIOFILTER FOR TREATING MIXED MALODOR GASES

[Technical Field]

The present invention relates to hydrophilic and hydrophobic packing media for bio-filters for the treatment of mixed malodorous gases. More specifically, this invention relates to the hydrophilic and hydrophobic bio-filter with a new concept where only the advantages of bio-filters of organic and inorganic media are applied.

[Background Art]

The functions of the packing media in bio-filters are a critical factor in malodorous gas elimination and operational cost. In general, desirable microbial media are light, have a large surface area and high water-holding capacity, and should be able to maintain their shape without biodegradation even after a long period of operation. However, existing fibrous media such as peat, compost and wood are easily biodegradable, which results in degradation after a long period of operation and increasing pressure loss, thus there is a frequent need to replace the media.

Meanwhile, the inorganic media that are currently in use often use oyster shells and ceramic media, which enjoy the advantage of non-degradation.

However, they are too heavy, have too low water-holding capacity, and require an enormous amount of additional water and nutritional supplies from the outside in order to keep microbes growing. Table 1 compares the physical and biological conditions of rock wool, organic media (compost and wood) and inorganic media (polyurethane foam and ceramic).

[Table 1 ] Physical features of bio-filter media

As seen in Table 1, rock wool is the most excellent medium among them, with the highest water-holding capacity, porosity and the lightest weight. However, its critical shortcoming is that since it is a fibrous medium, compaction occurs very quickly when it holds water, which results in increasing pressure loss.

Because of these reasons, this inventor has conducted research activities in an effort to develop a new medium that does not have the problems of the existing media. As a result of his research, the inventor came up with the solution to the aforementioned problems.

[Disclosure] [Technical Problem]

Therefore, the object of this invention is to provide hydrophilic and hydrophobic microbial media with light weight, large surface area and high water- holding capacity, while maintaining their shape even after a long period of operation.

The object of the invention could be achieved by using mixed rock wool and bentonite media, which can maintain shape and provide a high water-holding capacity.

[Technical Solution]

The hydrophilic and hydrophobic packing media for bio-filters for the treatment of mixed malodorous gases in this invention is composed of a mixture of organic and inorganic media in a certain ratio, where activated carbon, organic and inorganic binding agents are also added to form beads.

In the composition of this invention, the inorganic medium is rock wool and the organic medium is compost, preferably excrements of earthworm.

In the composition of this invention, the mixture ratio of organic and inorganic media can be 65 ~ 75 : 35 ~ 25. When the ratio falls outside the mentioned range, it is becomes undesirable in terms of biodegradability, water- holding capacity and weight.

In the composition of this invention, the above organic adhesive can be Polyvinyl alcohol (PVA), glutaraldehyde or TEOS, and the inorganic adhesive is bentonite.

In the beads manufactured as bio-filter media, which were composed in the manner described above, the rock wool media with high hydrophilic water- holding capacity is coated with PVA and cross-linking agents such as glutaraldehyde or TEOS can be added in order to enhance the media-binding capacity.

In addition, in the composition of this invention, pore size and porosity of the surface of the PVA media can be adjusted by controlling the corn starch. In the composition of this invention, nutrients and odor-degrading microorganisms can also be fixed together in the media.

Furthermore, in this invention, activated carbon is added in order to facilitate the physical absorption of hydrophobic gases to the surface of the PVA media.

Below are the detailed descriptions of the attached drawings for this invention.

First, it describes how to manufacture the media of this invention and the experimental conditions. FIG 1 shows the shape of the media manufactured according to the composition of this invention, and FIG 2 shows the manufacturing processes of the media.

First, compost that was passed through a sieve of between Mesh 9 and

Mesh 14, was used, rock wool was purchased from UR, and the mass ratio of the rock wool and compost for the mixture was 70:30. The water added amounted to

70% of the total weight. The ingredients were wet before they were mixed, and a little amount of activated carbons was added. After they were thoroughly mixed,

PVA and bentonite were added as organic and inorganic binding agents, respectively. And then, the mixture was manufactured into balls with a diameter of 0.8-1.0cm and dried for three to four hours in a 60 ^°C oven (refer to FIG 2).

The features, roles and purposes of each of the ingredients are as follows:

Rock wool is composed of 35-45% SiO₂, 20-40% CaO, 10-20% Al₂O₃, 0- 12% FeO, 0-12% Fe₂O₃ and 3-10% MgO, and comprises a major part of the culture medium. It has high porosity, high water-holding capacity, light weight, favorable drainage capacity, good buffering capacity, and both hydrophilic and hydrophobic features. However, it also has disadvantages such as a low 2% organic content, compaction when it contains water, and no nutrients. The compost added to supply the organic features and nutrients to the culture medium can be various and has high microbe density, excellent water suppression capacity, neutral pH and appropriate organic content. Its culture medium is more responsive to combining microbial cells. Meanwhile, when this ingredient is used alone, it generally shows significant pressure drops and high compaction, which is undesirable.

Activated carbon absorbs the polluted gases from the culture medium in the early stage. Activated carbon has favorable absorption capacity, acts as a buffer for inlet concentration that is highly fluctuating, has water-holding capacity, and provides favorable surfaces for holding microbes. However, its cost is high and it requires the addition of nutrients and microbes.

Polyvinyl alcohol, which is used as a bonding agent in this invention, is the most universally used and safest bonding agent in the microbial field. It is hydrophilic so it can absorb water for the culture medium. Lastly, Bentonite is a hardener that prevents melting in the water. It has high absorption capacity, whereas its disadvantage is high swelling and relatively poor permeability.

This invention will be described with more detail during the execution examples, while the scope of this invention is not limited to these examples. In addition, in the execution examples, the rock wool and compost ratio was fixed at 70:30, and the amount of activated carbon was also fixed, and then the ratios of organic and inorganic adhesive liquids were changed. Compost is an important factor in the media of this invention, as it provides organic features and nutrition. Furthermore, it provides active binding areas required to fix the microbes. On the other hand, as an inorganic medium, rock wool is added to provide the media with relatively high porosity, water-holding capacity and drainage capacity. In addition, activated carbon is added for its excellence in malodorous gas absorption in the early stage, while PVA and Bentonite act as organic and inorganic binding agents, respectively, to hold the ingredients together. The amounts of PVA and Bentonite are varied in the examples.

[Effects of the Invention]

The hydrophilic and hydrophobic packing media for bio-filters for the treatment of mixed malodorous gases manufactured as described above are ball- type, light-weight, hard in structure, excellent in porosity and water-holding capacity, and can contain additional nutrients and microbes. In addition, the packing media have excellence in physical features and in providing nutrition, water and the culture environment required for the growth and activities of microbes, excellent features for the operation of bio-filters such as pressure loss and compaction, and remarkable effects in removing hydrophilic and hydrophobic malodorous gases.

[Brief Description of the Drawings]

FIG 1 shows a section of the hydrophilic and hydrophobic media for bio- filters of this invention.

FIG 2 shows the overall manufacturing method for the hydrophilic and hydrophobic media for bio-filters of this invention.

FIG 3 is a photograph of the hydrophilic and hydrophobic media for bio- filters of this invention, which is filled in a cylinder for optimal operation.

FIG 4 shows the flow of the bio-filter system for the treatment of ammonia gas. FIG 5 shows the flow of the bio-filter system for the treatment of hydrogen sulfide gas. FIG 6 shows the flow of the bio-filter system for the treatment of toluene gas.

FIG 7 is a photograph of a bio-filter for the treatment of various gases using the media of this invention. FIG 8 shows graphs on the elimination rates of ammonia gas following the increase in its concentration, a) shows the elimination rate of Bio-filter A using rock wool only as media, whereas b) shows the elimination rate of Bio-filter B using the media of this invention.

FIG 9 shows a graph on elimination efficiency according to the media used in the bio-filter.

FIG 10 shows a graph that indicates the relation between the height of the media of the ammonia gas bio-filter and the pressure drop.

FIG 11 shows a graph on water held in the reactor.

FIG 12 shows graphs on the pH of the water from Bio-filter A using only rock wool as media and Bio-filter B using the media of this invention, as well as ammonium concentrations and bed temperatures.

FIG 13 shows a graph that indicates the ammonia gas elimination ability of Bio-filter A with only rock wool and Bio-filter B with the media of this invention. FIG 14 shows graphs on the concentration and elimination effects of hydrogen sulfide gas. 14a is for Bio-filter A using only rock wool, whereas 14b is for Bio-filter B of this invention.

FIG 15 shows graphs of the pH and sulfate concentration of the water drained after the hydrogen sulfate was removed. FIG 16 shows a graph on the water in the reactor.

FIG 17 indicates the relation between the height of the hydrogen sulfide bio-filter and pressure drop. FIG 18 shows a graph on the temperature changes in the reactor during the experiment.

FIG 19 shows graphs on toluene concentration and elimination efficiency. 19a is for Bio-filter A with only rock wool and 19b is for Bio-filter B with the media of this invention.

FIG 20 shows a graph on the pH changes of the water drained from the Toluene column.

FIG 21 shows a graph indicating the relation between the height of the toluene bio-filter and pressure drop. FIG 22 shows a graph on the water in the reactor.

FIG 23 shows a graph on the temperature changes in the reactor during the experiment.

FIG 24 shows graphs on the test results on the spike of reactors (Bio- filters A-F) in removing ammonia, hydrogen sulfide and toluene. FIG 25 shows graphs indicating the capacities of the bio-filters in eliminating ammonia, hydrogen sulfide and toluene.

FIG 26 shows ESEM photographs of the inside and the surface of the hydrophilic and hydrophobic media after the experiments were conducted according to the experiment examples of this invention.

[Best Mode]

Example 1

Bead-type media were manufactured, in which a 130-g rock wool- compost mixture (70:30 weight ratio) that contains 70% water, 3g granule type activated carbons, 30ml, 10% (w/v) PVA liquid, and a solution of 25g Bentonite in 35ml water were mixed. [Mode for Invention] Example 2

Except for the mixture of the solution of 35g bentonite in 49ml water, the media were manufactured in the same manner described in Example 1.

Example 3

Except for the use of 20% (w/v) PVA solution, the media were manufactured in the same manner described in Example 1.

Example 4

Except for the use of 20% (w/v) PVA solution and the mixture of the solution of 15g bentonite in 21ml water, the media were manufactured in the same manner described in Example 1.

Example 5

Except for the use of 20% (w/v) PVA solution and the mixture of the solution of 25g bentonite in 15ml water, the media were manufactured in the same manner described in Example 1.

Example 6

Except for the use of 20% (w/v) PVA solution, the mixture of the solution of 15g bentonite in 21ml water, and the addition of 6.5 g limestone powder, the media were manufactured in the same manner described in Example 1.

Example 7 Except for the use of 20% (w/v) PVA solution, the mixture of the solution of 15g bentonite in 21ml water, and the addition of 6.5g limestone powder, the media were manufactured in the same manner described in Example 1.

Experimental Example 1

Measurement of physical-chemical features of the media

The features of the media manufactured according to each of the execution examples were measured through the methods described in Table 2. The results of the measurements are described in Table 3. [Table 2]

Physical-chemical test of hydrophilic and hydrophobic media

[Table 3]

Among the items above, for 'After submerging in water' and 'After submerging in acid solution', 1 refers to hard structure, 2 refers to not-so-hard structure, 3 refers to somewhat softened structure, 4 refers to softened structure, and 5 refers to undesirable structure.

The features of the media shown in Table 3 indicate that the media in Example 5 were light and did not experience structural changes in the acid solution, and therefore, were proven to be the most suitable media for bio-filters. FIG 3 is a photograph of the media manufactured according to this example.

Experimental Example 2

Reviews on optimal operational conditions

In order to compare the functions of the media of this invention, experiments were conducted on the ability of bio-filters to eliminate ammonia, hydrogen sulfide and toluene (hydrophobic) gases, based on which the optimal operational conditions for bio-filters using the media of this invention were sought.

1) Microbe fixing The media were mass-produced according to the execution examples of this invention, and the microbes for gas degradation were fixed on the culture medium as in Table 4. For ammonia-treating microbes and hydrogen-treating microbes, ImI pure culture fluid was placed in IL culture medium and mixed at 150rpm and 28 °C for two to three days. The culture medium was centrifuged at

7000rpm for 20 minutes, and the concentrated part was placed in a new culture medium without NH₄Cl for ammonia-treating microbes and another new culture medium without Na₂S₂O₃ ^• 5H₂O for hydrogen sulfide-treating microbes. They were cultured for a certain period of time, and then the microbes were fixed in the media.

For toluene-treating microbes, ImI pure culture liquid was placed in a liquid culture medium where glucose was used as carbon source. It was mixed at 28 °C and 150rpm for two to three days. The culture medium was composed of

10g/L glucose, 5g/L yeast extract, 5g/L (NH₄)₂SO₄, 5g/L KH₂PO₄, and lg/L MgSO₄ ^• 7H₂O. The concentrated part after the centrifuge was transferred to the culture medium as in Table 4 and cultured for five days. The flask was corked with a silicon plug coated with teflon to prevent the loss of toluene. The culture medium was centrifuged once again, and then the concentrated part was transferred to a new culture medium without toluene, cultured for two days and fixed.

For the purpose of comparison, the microbe-fixing on rock wool media was conducted in the same manner as above.

[Table 4] Compositions of mineral culture media for other microbes

2) Bio-filter equipment using the media of the invention and experimental conditions

FIG 4, 5 and 6 show bio-filter systems for the treatment of ammonia, hydrogen sulfide and toluene gases. Each of the gases was infused in equilibrium into the rock wool media and the media of this invention. The initial operational conditions are described in Table 5, and FIG 7 shows a photograph of the bio- filter response system.

[Table 5] Initial operating parameters for the bio-filter experiment

Experimental Example 2

Gas elimination experiments of bio-filters using the media of this invention φ Experiment of ammonia gas elimination

Ammonia gas elimination

FIG 8 shows the results of the two bio-filters made up of the existing rock wool media and the media of this invention, with the concentration of ammonia gas increasing in 64 days. The initial ammonia gas concentration was 19ppm_v. The initial inlet concentration was 0.7528g-NH₃/m³/hr for Biofiter A (rock wool) and 0.7887 g-NH₃/m³/hr for Bio-filter B (the media of this invention). After 8 days, the ammonia concentration was increased to 150-160ppm_v,

According to the results shown in FIG 8, Bio-filter B, with the media of this invention, displayed superior elimination capacity than Bio-filter A. Up to 46 days, when the inlet concentration was 155ppm_v, the elimination capacity was 98

- 100%. However, when the concentration was further increased to the next stage, the elimination capacity was slightly reduced to -90%. Meanwhile, Bio-filter A, using rock wool as media, showed poor ammonia gas elimination rate of 10-50% for 11 to 46 days. The relatively better elimination rate for the initial seven days is attributed to the absorption.

The elimination rate of Bio-filter B was down to 67% in 8 days after the inlet concentration of ammonia gas was increased to 155-165ppm in the 53rd day. At this stage, as the air flow rate of the inlet air was reduced from 1.5L/min to 0.75L/min, EBRT doubled from 62.8 seconds to 125.6 seconds for Bio-filter A and from 65.9 seconds to 131.9 seconds for Bio-filter B. As a result, the elimination rate of Bio-filter B rose again to 98%, whereas that of Bio-filter A stayed at around 60%. FIG 9 shows the comparison of the elimination rates of the two bio-filters.

Changes in other factors

Media samples were collected from the bio-filter reactors. From the samples, water content, pH, ammonia ion concentration and microbial count were analyzed every 14 days. FIG 10 indicates the height of the media and pressure drop during the experiment period. Bio-filter A with rock wool shows a decrease in the height of the media, which is attributed to its fibrous structure that can be easily compressed when it is wet due to its high porosity and water-holding capacity. After operation for 59 days, the height of the media was decreased by 5.20cm. On the other hand, Bio-filter B with the media of this invention showed a decrease of only 1.Ocm in height after 59 days of operation. The results prove that the newly-invented media have better mechanical strength such as material decomposition, bed compaction and water condensation. In addition, the invented media are light and are expected to minimize compression at the bottom of the reactor. The pressure drops were more increased in Bio-filter A than in Bio-filter

B. On the 52nd day, the pressure drop of Bio-filter A was 26.78mmH₂O/m bed, whereas that of Bio-filter B was 10.00mmH₂O/m bed. The low pressure drop of Bio-filter B is attributed to the ball shape of its media, which is not easily compressed and provides space through which air can flow well. Since the pressure drop is in direct proportion to the air flow rate, the pressure was decreased as the air flow rate was reduced from 1.5 to 0.75L/min on the 53rd day. The water contained in the reactor is shown in FIG 11. The microbial count (CFU/g media) was attained from media samples regularly collected. The analysis of microbial count is shown in Tables 6 and 7 together with the pH of the media samples.

[Table 6] Microbial count in media samples from NH₃ columns

CFU/g media

Days Elapsed

Rock wool only Rock wool-Compost media

1 4.76E+06 2.98E+06

8 8.00E+06 4.05E+06

16 1.01E+07 2.01E+07

24 5.97E+07 1.50E+08

45 1.47E+08 1.83E+08

59 5.87E+08 5.78E+08

[Table 7] Variation of media pH in NH₃ columns

Media pH

Days Elapsed

Rock wool only Rock wool-Compost media

16 8.10 7.38

24 7.72 7.66

45 8.18 7.88

59 8.60 7.92

The pH of the media of the invention was between 7 and 8, which is the most appropriate pH for bio-filters. The results of the analysis on the water drained from the two filters were also indicated in FIG 12. The increased ammonium ion concentration was reduced by the solution of ammonia gas. The pH of the drained water was appropriately between 7 and 8.5 (FIG 12). The temperatures of the reactor are seen in FIG 12. Elimination capacity

FIG 13 shows the elimination capacities of Bio-filters A and B according to the ammonia inlet. It indicates that Bio-filter B is superior to Bio-filter A in this regard. The maximum elimination capacity of Bio-filter A was 3.55 g- NH₃,_removed/ni³ _bed/hr (2.92 g-N/m³ _bed/hr), whereas that of Bio-filter B was 6.44 g-

NH_3,remOved/m³ _bed/hr (5.30g-N/m³ _bed/hr).

(2) Experiment on hydrogen sulfide gas elimination

Hydrogen sulfide gas elimination FIG 14 shows hydrogen sulfide gas concentration and elimination efficiency. Bio-filter C is a rock wool media system, while Bio-filter D is the media system of this invention. The initial inlet concentration was 20ppmv. Bio-filter C showed a high elimination rate of 95-100% in the first few days. However, when the inlet concentration was increased to 60-70ppmv, the elimination rate started to become unstable. When the concentration was further increased to 90-100ppmv, the instability also increased. However, when the air flow rate was reduced, the elimination rate rose to 100%. Meanwhile, Bio-filter D maintained a high elimination rate of 90% or above for up to the 40th day even when the inlet concentration was increased to 150ppmv. The elimination rate was lowered to 60% when pH and water content were lowered, and then was recovered to about 80% when pH and water content were adjusted.

Analysis on drained water

FIG 15 shows the pH and sulfate ion concentration of the drained water.

The acidic condition due to the oxidation of hydrogen sulfide could be detected. Due to the acidic environment, the microbes were deactivated, and consequently, the elimination efficiency deteriorated. Thus, the pH of the two reactors were controlled by adding 0.33N NaOH. Bio-filter D, with the media of this invention, more efficiently oxidized hydrogen sulfide to increase the concentration of the sulfate ion. As seen in the pH results, Bio-filter D also showed a better buffering capacity.

Analysis on media FIG 16 shows the water content of the media. Similar to the ammonia elimination experiment, a decrease in water content was detected on the 45th day, so additional water was provided. Providing water to the hydrogen sulfide elimination system not only provides water to the microbes but also minimizes the drop in pH with regards to sulfate ion dilution. It was observed that the loss of water content is related to the decreased elimination rate.

FIG 17 shows the pressure drop and bed compaction. The bed compaction of the rock wool media was 3.6cm on the 59th day, whereas that of the media of this invention hardly changed. The rock wool media system saw a maximum pressure drop of 14.37mmH₂O/m, while that of the media of this invention was only 6.31 mmH₂0/m.

FIG 18 shows the temperature changes during the period of experiment.

Table 8 and 9 show the microbial count and pH of the media. It was proven that the media of the invention shows an increase of microbial count over time due to more nutrients. The pH of the media was high, as it was measured after pH adjustment by adding NaOH solution.

[Table 8] Microbial count in media samples from H₂S columns

(3) Experiment on toluene gas elimination Toluene gas elimination

FIG 19 shows the results of the experiment on toluene gas elimination for 57 days using Bio-filter E with rock wool media and Bio-filter F with the media of the invention. The initial inlet concentrations of Bio-filters E and F were 12.73ppmv and 10.46ppmv, respectively. The initial elimination efficiency was almost 100%. However, when the inlet concentration was increased from 100 to 200ppmv, the elimination rate of Bio-filter E dropped from 90% to 40%. On the other hand, Bio-filter F displayed a 100% elimination rate up to the 30th day, when the inlet concentration was 260ppmv. However, it also fell to 75% over time. The decreased elimination rate rose again when the inlet concentration was reduced to lOOppmv, water was added, and the gas residence time was extended to 131.88 seconds. Thanks to the activated carbons contained in the media, Bio- filter F with the media of the invention showed a high elimination rate despite a high inlet concentration and also enjoyed the elimination effect by absorbing hydrophobic gases. Analysis on drained water

FIG 20 shows the pH of the drained water. The pH ranged from 6 to 7.4. The lowered pH was expected as toluene was decomposed to produce organic acid. However, the degree of lowered pH observed was not to the extent of significantly hindering the activation of microbes.

Analysis on media

As for the media compaction, it hardly happened to the media of the invention, and the rock wool media also displayed a low pressure drop (refer to FIG 21). As indicated in Table 10 below, the microbial count for Bio-filter F decreased in the first 6 weeks, which is attributed to the high concentration toluene inlet and media dryness. FIG 22 also shows the decreased water content on the 38th day. This seems to be related to the lowered elimination rate. Since toluene does not easily melt in water, the loss of water content may contribute to the improvement in mass transfer on the gas/biofilm surface. However, overall, the decreased water content resulted in lowered microbial count and activation and had a negative impact on the elimination capacity of the bio-filter.

[Table 10] Microbial count in media samples from toluene columns

Table 11 below shows the pH of the media. The temperature of the reactor ranged between 22 "C and 30 ^°C (refer to FIG 23). The optimal temperature for the activation of microbes is between 22 ^°C and 35 ^°C, and the hydrophobic gas elimination can be hindered at a temperature of 40 ^°C or higher. This shows that the temperature in the reactor is appropriate for both microbe activation and gas elimination. [Table 11 ] Variation of media pH in toluene columns

A spike test refers to a test to observe the reactions of bio-filters to an abrupt increase in inlet concentration. FIG 24 shows the results of the spike tests on Bio-filters A to F, which are the reactors for removing ammonia, hydrogen sulfide and toluene gases. The inlet concentration of ammonia gas was increased from 80ppmv to 160ppmv, the inlet concentration of hydrogen sulfide was up from 75ppmv to 150ppmv, and the inlet concentration of toluene increased from lOOppmv to 200ppmv. The media system of this invention displayed excellent functions for all gases. Of particular note, the function was outstanding for ammonia and toluene gases. On the other hand, rock wool media showed good elimination rates for hydrogen sulfide within the range of concentration applied in the test.

© Elimination capacity FIG 25 shows the elimination capacities of the bio-fϊlters for treating ammonia, hydrogen sulfide and toluene. Table 12 below shows the elimination capacities for each of the gases.

[Table 12] Elimination Capacities of the columns for NH₃, H₂S and Toluene

The ammonia and hydrogen sulfide elimination volumes of the media of the invention were low to some degree, though not so bad. Since the elimination rate was normal, this result is thought to be due to the limited volume of the bio- filter reactor. The diameter of the reactor column was 0.1m while the floor height was 0.22m. In this reactor dimension, the contact time between the gas phase and the liquid phase on the media surface is short to some degree, and the mass transfer mechanism is inefficient in high gas concentration. Consequently, these affect the elimination rates. The toluene-treating bio-filter system displayed a good elimination rate.

This is attributed to the addition of activated carbons.

© Analysis on ESEM on the surface of the media of the invention FIG 26 shows the ESEM photographs of the surface and inside of the media of this invention after the experiment. As expected, on the surface and inside the media of the invention, a thick bio-film could be observed on the surface of the rock wool fiber. A relatively smaller amount of bio-film was observed in the ammonia-treating media.

[Industrial availability] This invention relates to hydrophilic and hydrophobic packing media for bio-filters for the treatment of mixed malodorous gases. It is a useful invention since it is excellent in terms of physical features and in providing nutrition, water and the culture environment required for the growth and activities of microbes, desirable features for the operation of bio-filters such as pressure loss and compaction, and remarkable effects in removing hydrophilic and hydrophobic malodor gases.

Claims

[CLAIMS] [Claim 1]

A hydrophilic and hydrophobic packing media for bio-filters for the treatment of mixed malodorous gases characterized in the media is composed of a mixture of organic and inorganic media in a certain ratio, in which activated carbon, organic and inorganic binding agents are added to form beads. [Claim 2]

The media according to claim 1 , characterized in the inorganic medium is rock wool and the organic medium is compost. [Claim 3]

The media according to claim 1, characterized in the mixture ratio of organic and inorganic media is 65 ~ 75 : 35 ~ 25. [Claim 4]

The media according to claim 1, characterized in the organic adhesive is Polyvinyl alcohol (PVA), glutaraldehyde or TEOS, and the inorganic adhesive is bentonite. [Claim 5]

The media according to claim 1, characterized in nutrients and odor- degrading microorganisms are fixed together in the media when manufacturing the media.