Ozone dalam Aplikasi industri makanan dan pertanian

LAIN bidang dari pemanfaatan: 

Di sini, referensi akan dilakukan untuk kemungkinan untuk cepat dan efisien kehancuran dalam suasana ozon berbagai non-patogenik mikro-organisme termasuk cetakan, spora dan makhluk primitif sel tunggal lainnya. Kemungkinan luas menggunakan ozon di industri makanan dan pertanian juga dalam bidang lain, demikian pula diciptakan oleh itu bakteri dan kuman membunuh kekuasaan. 

Tidak hanya itu bertindak sebagai germicide tetapi sebagai agen pembunuhan spora juga. Buah-buahan, bahan makanan, dll, terkena efek, di bawah pergi perubahan lebih atau kurang diucapkan sebagai konsekuensi dari tindakan itu pada proses penting sel, proses metabolisme ada khususnya, melalui inaktivasi produk metabolisme mereka. Pada saat yang sama ia bereaksi dengan bahan lain hadir yang dapat teroksidasi dan dengan demikian itu menghancurkan wewangian dan bau. 

Pemanfaatan sifat-sifat ini membuat ozon nyata cocok untuk meningkatkan kehidupan penyimpanan makanan tahan lama didinginkan lokal. Pada saat yang sama itu digunakan secara ekonomi sebagai investasi dan biaya operasional peralatan pada tingkat yang dapat diterima dalam kaitannya dengan ukuran kamar didinginkan. Itu aplikasi menghilangkan resiko dari meninggalkan bau yang tidak menyenangkan atau jejak antiseptik yang digunakan untuk pelestarian pada bahan makanan lainnya. 

Pemanfaatan ozon untuk meningkatkan kehidupan penyimpanan makanan, terutama jika diadakan pada suhu rendah, diyakini telah dimulai pada tahun 1909 ketika, pada tanaman cold storage Cologne, pengurangan dalam hitungan kuman pada permukaan daging yang disimpan di sana terlihat setelah ozon generator telah dipasang di saluran udara segar yang digunakan untuk ventilasi ruang penyimpanan. Lebih luas ujian dan percobaan ini dibutuhkan pada Penyimpanan buah-buahan dalam penyimpanan dingin tanaman untuk memutuskan apakah perawatan oleh ozon dapat dianggap menguntungkan atau tidak menguntungkan karena persyaratan yang berbeda dikenakan pada Penyimpanan berbagai buah-buahan. 

Meskipun beberapa publikasi atau laporan penelitian yang belum menjadi bagian dari domain publik, penggunaan ozon meningkat di beberapa tanaman penyimpanan dingin utama di Eropa. Van Laer dan Troquet dijelaskan, sedini tahun 1928, pemanfaatan ozon di tempat pembuatan bir. R.I. Tenny fokus perhatian lagi 1972 pada kemungkinan untuk digunakan dalam industri pembuatan bir. Kekurangan teknis dari generator ozon di tahun 1940-an yang bertanggung jawab untuk kemunduran yang dihadapi saat itu

PELESTARIAN dan penyimpanan operasi praktis untuk pelestarian mulai dengan sterilisasi terhadap udara sedemikian rupa bahwa udara yang masuk ruang berisi jumlah yang cukup ozon untuk menghancurkan mikro-organisme. Pada saat yang sama, namun, ozon dekomposisi banyak diharapkan karena kadar tinggi diperlukan, dinding ruang penyimpanan bahan Kemasan, efek penyerapan disimpan barang, dan juga untuk reaksi oksidasi berlangsung. Persyaratan ini dua permintaan distribusi paling sempurna ozonated udara di ruang penyimpanan dan membuatnya penting bahwa kapasitas generator ozon menjamin pemeliharaan konsentrasi ozon sesuai sepanjang seluruh massa udara. 

Sebaliknya mungkin terjadi bahwa ozon tidak akan mencapai ruang penyimpanan dengan benar, apalagi permukaan barang disimpan. Efek yang diperlukan dapat dicapai oleh gerakan udara yang kuat, Ruang Penyimpanan, pada gilirannya, perlu tidak akan tertutup rapat seperti, misalnya, dalam kasus penyimpanan di bawah statis dalam atmosfir gas CO2. 

Keadaan kesetimbangan dapat mengatur, bahkan di tempat ini relatif tertutup, antara jumlah ozon yang dikonsumsi oleh lingkungan bahan kemasan dan tembok dll, melalui penyerapan, dan dimanfaatkan oleh barang disimpan (untuk menghancurkan permukaan kuman, oksidasi metabolik produk dll.) pada satu sisi, dan jumlah ozon yang diperkenalkan pada yang lain. Setelah berhenti pakan, dekomposisi berlanjut yang ozon disediakan sampai waktu tertentu oleh desorption dari lingkungan; Meskipun demikian, penipisan ozon konten total set dalam cepat. Selama penyimpanan, ozon diberikannya efek tiga oleh menghancurkan mikro-organisme, mengoksidasi bau dan mempengaruhi proses metabolisme.

EFEK YG MENGHAPUS KUMAN PENYAKIT

Efek ini ozon telah sudah dibahas secara umum persyaratan. Untuk aplikasi dalam industri makanan, penekanan lebih besar harus dimengerti diletakkan pada perubahan dalam kualitas berlangsung setelah pengobatan ozon, bersama dengan efek khusus yang diberikan pada produk individu. Yg menghapus kuman penyakit kekuatan ozon umumnya khusus dengan masing-masing spesies. Itu tindakan utama pada cetakan adalah untuk menekan ada pertumbuhan dan efek ini dapat mengatur dalam pesat, terutama pada tahap awal pada permukaan cetakan gratis. Setelah proses ini menyebabkan kehancuran budaya yang sudah dibentuk. Ozon segera menyerang sel-sel yang mudah diakses di permukaan karena ozon diberikannya efek permukaan di tempat pertama dan memiliki kedalaman hanya sedikit penetrasi. Kolodyaznaya dan Sponina diselidiki flora mikro yang menyebabkan kerusakan kentang.

Budaya murni jamur Fusarium Solani, Rhisoctonia Solani dan Phytophtora Solani terkena tindakan ozon. Dari spesies ini Fusarium Solani terbukti resisten terhadap ozon. Ozonization diterapkan untuk penyimpanan berpendingin daging menghancurkan permukaan mikro-organisme, terutama keluarga Pseudomonas bertanggung jawab untuk pembusukan. Meningkatkan kadar lingkungan menguntungkan mempengaruhi efek yg menghapus kuman penyakit. Hal ini disebabkan oleh pembengkakan mikroba yang membuat mereka lebih rentan terhadap kerusakan. Eksperimen dilakukan dengan daging sapi yang menunjukkan bahwa ozon paling efisien jika permukaan memiliki kandungan pasti kelembaban sekitar 60%.

EFEK PADA BAU 

Ozon itu sendiri memiliki bau khas, namun hasil dari aplikasi tidak menutupi bau. Atom oksigen yang dibentuk oleh dekomposisi ozon segera mengoksidasi bahan-bahan yang berbeda berbau. Karakteristik bau busuk, bagaimanapun, tetap dan sulit untuk menghilangkan bahkan dengan penggunaan ozon. Secara umum, semakin rendah suhu dan semakin besar molekul yang mengambil bagian dalam reaksi, lemah adalah mengoksidasi efek. Kandungan kelembaban di udara tidak berpengaruh pada proses. Pada konsentrasi yang sangat sedikit, mengatakan antara 0,01 dan 0,04 ppm. ozon, udara kamar ruang penyimpanan merasa segar dan menyenangkan dan tidak ada bau pengap merasakan lagi. Ini adalah fakta bahwa bau buah-buahan aromatik seperti stroberi ditingkatkan hadapan ozon. Dimungkinkan bahwa pembentukan wewangian dan bau yang memberikan buah rasa khas yang dibantu oleh ozon. Sterilisasi udara di toko-toko buah dengan ozon mencegah bau bahan kemasan dipindahkan ke barang yang disimpan, sebuah fenomena yang sering mengambil tempat lain, terutama ketika peti kayu yang digunakan di toko-toko berpendingin kelembaban relatif dari 85% sampai 90%.

EFEK PADA METABOLISME 

Efek pada metabolisme juga merupakan konsekuensi dari oksidasi kuat kekuatan ozon. tidak ada kerusakan buah diamati, tetapi alasan untuk ini adalah bahwa ozon hanya mempengaruhi permukaan buah yang mengandung senyawa sulit untuk mengoksidasi dalam kebanyakan kasus. Selama penyimpanan proses respirasi buah adalah dipercepat dan begitu adalah pematangan. Dalam kasus yang masak lebih cepat daripada yang diinginkan, etilena diproduksi yang mempengaruhi buah lain dan jadi memprakarsai pematangan bahkan lebih intensif.

Tanda-tanda eksternal dari proses ini adalah berpaling cokelat kulit, pelunakan daging dari sisa buah dan, akhirnya, pembusukan. Proses ini dikendalikan oleh kehadiran ozon karena itu mengoksidasi produk metabolik yang dibuat pada awalnya, dengan demikian mengurangi proses belakang tindakan pada buah-buahan lainnya. Selain itu, ini mempromosikan penyembuhan luka dan meningkatkan resistensi terhadap infeksi lebih lanjut.

DAGING

Untuk penyimpanan daging ditemukan bahwa efek memuaskan yang dapat ditimbulkan oleh satu atau dua periode harian aplikasi ozon, tahan dua jam setiap kali jika konten ozon diadakan di 6 mg. (0) m. (udara).

Penerapan ozon terbukti sangat bermanfaat untuk proses Anda tenderizing daging. Selama Anda tenderizing, daging sapi segar sisi disimpan selama berjam-jam 42-44 dalam ruang tertutup pada suhu 293K dan kelembaban relatif 85%. Proses tenderization terdiri, dalam kenyataannya, tindakan pencernaan yang disebabkan oleh enzim alami hadir untuk melunakkan dan mengendur otot dan jaringan penghubung. Proses yang sama dapat mengambil sebanyak 20 hari di suhu 279K. Efek percepatan kenaikan suhu di tenderization mempromosikan pembentukan tanah subur yang cocok untuk perkalian dari infeksi bakteri dan spora merugikan alam. Tujuan harus dicapai dengan pengobatan ozon adalah kehancuran organisme permukaan ini berbahaya. Di seperti Anda tenderizing kamar konsentrasi 0.1 ppm.

dan kelembaban relatif 60% sampai 90% harus dipertahankan, menurut Ewell. Menurut orang lain, ozon efisien, bahkan jika hadir dalam konsentrasi 0,04 ppm. dan, meskipun gagal untuk membawa penuh sterilisasi, itu masih menghambat pertumbuhan bakteri. Tindakan yg menghapus kuman penyakit ozon dibatasi hanya untuk permukaan dalam kasus daging terlalu, dan memiliki kedalaman penetrasi kecil. Cetakan hadir dalam bentuk spora dapat dihancurkan hanya jika diserang oleh konsentrasi tinggi ozon. Masa penyimpanan daging sapi dalam keadaan didinginkan dapat ditingkatkan oleh 30% sampai 40% jika daging sapi yang disimpan dalam suasana 10 sampai 20 mg. (0) m (udara) dan saturasi mikroba permukaannya tidak lebih besar dari bakteri 10 cm. milyar dilakukan penyelidikan lebih detil pada t Dia kehidupan penyimpanan daging sapi, daging sapi, domba, babi, ayam, dan kelinci di atmosfer ozonized. Dalam hal jenis daging yang disimpan dalam suasana yang normal, ditemukan bahwa cemaran mikroba signifikan menetapkan setelah 7 hari. Kontaminasi dari tingkat yang sama tiba pada daging yang terkena tindakan ozon hanya setelah 14 hari di bawah kondisi yang identik. Itu bisa dinyatakan secara umum bahwa, dalam suasana yang didinginkan dan di depan mata ozon, pertumbuhan flora mikro permukaan (Pseudomonas Keluarga, spora, salmonellae, staphylococci) adalah melambat. Namun demikian, tidak ada efek yang diberikan oleh ozon Flora mikro permukaan jika tingkat pencemaran besar sudah.

Dengan demikian, meskipun ozon gagal untuk menghasilkan efek Check antiseptik pada daging disimpan, itu masih membuat suasana toko berpendingin segar dan sehat. Ikan yang baru saja ditangkap dapat disimpan lebih lama jika dicuci dalam air yang mengandung ozon; Jika itu yang diawetkan dengan es yang dihasilkan dari ozon yang berisi air meningkat lebih tinggi dalam waktu penyimpanan bebas kerusakan dapat diperoleh.

EGGS 

Ozon telah berhasil digunakan untuk penyimpanan telur. Pada akhir tahun 1930-an, lebih dari 80% dari toko-toko berpendingin telur di Amerika Serikat dilengkapi dengan ozon menghasilkan peralatan untuk meningkatkan kehidupan penyimpanan.

BEVERAGES 

Ozon pengobatan mempercepat penuaan anggur, menghindari kekeruhan, dan menyempurnakan bouquet nya, yang dipertahankan untuk waktu yang lama. Kehidupan penyimpanan susu, botol jus dan minuman ringan juga ditingkatkan dengan ozon melalui menekan asam pembusukan. Terlepas dari kota air pasokan jumlah besar air botol didesinfeksi dengan ozon ritel di Amerika Serikat. Sterilisasi air yang diperlukan untuk produksi minuman adalah subjek yang signifikan karena permintaan yang meningkat untuk air berkualitas baik oleh produksi tanaman. Untuk produksi skala industri minuman ringan, air humat socalled dapat digunakan yang sempurna dalam memenuhi persyaratan biologis (rasa, bau), tetapi mereka warna kecoklatan tidak diinginkan. Warna ini diambil dari tanah dapat dihilangkan dengan ozon. Syarat utama untuk dipenuhi mempertahankan negara steril di periode 4-8 minggu yang elapsing antara mengisi dan konsumsi. Ozon telah terbukti menjadi metode yang paling efisien untuk sterilisasi melebihi proses konvensional digunakan sebelumnya seperti UV, iradiasi, klorinasi, perak pengobatan, sterilisasi penyaringan. Salah satu minuman ringan yang paling banyak dikonsumsi adalah air mineral botol. Banyak nilai, namun, mengandung Mangan dan besi. Jika metode yang biasa diterapkan untuk menghilangkan mangan dan besi, konten yang secara alami dilarutkan karbon dioksida sebagian besar habis.

Penggunaan ozon dalam hal ini adalah keuntungan tertentu seperti besi dan mangan dapat lengkap teroksidasi oleh ozon dengan retensi simultan konsentrasi tinggi karbon dioksida terlarut. Ozon juga digunakan dalam industri susu, untuk menekan souring. Langkah sterilisasi seperti sangat meningkatkan kehidupan penyimpanan. Dalam industri pembuatan bir, ozon dapat digunakan dengan keuntungan untuk disinfeksi jalur pipa, filter, botol, dll. Jika ada limbah fenolik, klorin mengoksidasi mereka untuk chlorophenols, yang memiliki selera dan bau tak tertahankan bir. ozon menciptakan titik-titik khusus minat khusus untuk bir dan pengguna proses serupa lainnya karena merupakan biosida dengan residu yang non-persistent dan beracun.

DISINFECTION AND REMOVAL OF ODORS Storage places, warehouses and

refrigerated stores can be disinfected in most cases by the admission of

ozonized air. This is independent of the direct action exerted on food, fruits,

beverages, etc. stored there. Such a process, apart from disinfection,

removes the frequently unpleasant odors of packaging materials so the

various produces retain there original flavour. It happens frequently that

the stored products, due to insufficient air locking, imperfect separation or

facilities for communication. The oxidation of compounds creating odors in

such premises has the advantage that it creates an atmosphere resembling

pleasant fresh air. For such a purpose a very low ozone concentration of

0.01 to 0.04 ppm. is sufficient. In refrigerated tunnels, meat tenderizing

halls and meat warehouses, ozone is generated by special sterilization

lamps. These are designed to have a portion of there radiation band in the

range below 200nm. so they have an active photochemical ozone generation

effect. Initially, when by product ozone was discovered in the application of

UV lamp systems, efforts were made to restrict the formation of traces of

ozone associated with the use of these lamps. Later it was found that the

presence of ozone at concentrations of up to 0.1 ppm. by volume protects

meat from decay. The increase in storage life (see preceding section) had

the secondary benefit of reducing odors. The effect of ozone in a domestic

refrigerators was also investigated. Here to, sterilizing lamps were used for

ozone generation. It was necessary to find a balance between the amount of

ozone potentially available and ozone demand that mold and bacteria on the

food and the refrigerator walls would be destroyed and the level of food

odor and there transfer to other foods would be greatly reduced. Ozone, if

present at a concentration of 0.1 ppm. is capable of destroying microorganisms

and removing odors after an exposure lasting about 48 hours. A

longer exposure time (At lower concentrations) is equivalent in terms of

bactericidal effect; it fails, however to eliminate the odors.

APPLICATION FOR AGRICULTURE Ozone is eminently suitable for the

processing of various by-products and secondary products originating in the

agriculture and food industries. It has proved suitable for the bleaching of

bees wax, starch, flour, straw products, bones, feathers, lard among others.

The majority of these products become whiter after treatment and there

smell is improved. If cotton and wool are treated with ozone, the grease and

wax like materials on the surfaces of fibres are decomposed. The removal of

these substances increases significantly the storage life of cotton fibre and

improves the dye ability of wool with a simultaneous bleaching action. The

Ozonization of flax speeds up the process of ripening and facilitates further

processing. For the removal of odors from large stalls, ozone has long been

used in the Soviet Union, the United States and Canada, in conjunction with

the process described previously.

OTHER FIELDS OF APPLICATION Finally, fields of application that have not

been referred to previously will be summarized. At the same time, the

processes and methods described previously will serve as examples for a

variety of further applications where each of them uses a high reactivity of

ozone in some form. The textile industry uses ozone to bleach various basic

materials, yarns and textiles. Health protection or, in an indirect way,

medical science examined long ago the disinfecting and bacterial action of

ozone in the interest of its use on a wide basis. In this framework,

successful experiments were conducted for the bleaching of hospital linen

with ozone generated via sterilizing lamps. Orlowski reports on the

disinfection of bandages and surgical devices where the action of ozone was

used instead of the conventional temperature effect. Chemical industry and

metallurgy utilize the process described previously for the neutralization of

vent gases from sewage works, to remove industrial odors which are

frequently harmful to health. For deodorization, of refresh of air in rooms

accommodating large masses of people such as theatres, assembly halls,

etc., and for improving air in offices, ozonized air is used widely in

conjunction with air conditioning systems. In this way, demand for make-up

air is reduced as the recycle system furnishes air of sufficient purity. For

premises such as theatres, assembly halls, etc., stringent code requirements

limit the allowable concentration of ozone in the air; this concentration

must not exceed several ppm. generally. At the same time it has been

proved that the effect of various unpleasant smells and body odor, cigarette

smoke, etc., can be eliminated in practice by treatment with a small amount

of ozone.

SWIMMING POOLS In the field of the classical water and wastewater

treatment, further new applications have been found for ozone processes.

According to official regulations, only hygienically and aesthetically perfect

water is allowed to be used in baths and swimming pools due to infection

hazard. Ozone as a dominating disinfectant, is not only efficient in

reconditioning bathing water due to the destruction of spores and viruses,

as well as the decomposition of human urine, but its use brings economies

owing to a reduction in the demand for make-up water. Equipment normally

used to purify drinking water complemented by special units required for

the application is suitable also for the reconditioning of bathing water.

(Reconditioning means an appropriate recirculation method to ensure

proper filtering and dispersion of the disinfectant). In Switzerland,

hundreds of indoor and outdoor swimming pools are equipped with these

ozone treatment devices today. The development of the "Sauter-Var Ozone

Process" is due to the Swiss firm A.G., which also supplies the ozone

generator. No injury to health has been experienced so far in baths

operated with ozone reconditioning. An essential part of the "Complex

ozone-per mutate-mixed-bed filter" process is formed by the filter,

inoculated with ions of heavy metals and metal oxides. The name of the

"Indirect Quant ozone" process applies the use of ozone mixed indirectly

into water. It is used particularly for the purification of the water in salt

thermal baths. The "Combined Ospa Chlorine-Oxygen" process is based on

the production of chlorine by the process of electrolysis. The electrolytic

allows a concentrated oxygen content in the bathing water, with the

consequent presence of traces of ozone. The number of processes clearly

shows the headway ozone has made in this special field. Apart from the

uses of ozone, an essential feature of all these processes is the

incorporation of water purification steps into the process. A more detailed

discussion of this subject, however, would go beyond the parameters of this

paper. The sometimes sketchy description of the multitude of applications

shows the increasing utilization of ozone in a great variety of technical

fields. From this review in can be inferred that the uses of ozone in certain

areas is not yet fully competitive with other long established methods. Thus

ozone represents no cure-all, but it has definite advantages in many cases

making worth-while a search for its economic use. In addition to the

applications described here, a great number of possibilities will develop in

the future for which only laboratory experiments have so far been carried

out.

CHEMICAL REACTIONS OF OZONE The chemical reactions of ozone are

related to its molecular structure. One of the oxygen atoms can be detached

relatively easily, yielding there-by nascent oxygen, and this makes ozone

practically the strongest oxidizing agent. In other reactions, the whole of

the ozone molecule can be added to a reagent. Ozone takes part in inorganic

reactions as an exceptionally powerful oxidizing agent. This behaviour

follows also from its high redox potential, exceeded only by that of fluorine.

It oxidizes metals (with the exception of gold, platinum, iridium) to oxidize

of the metals in there highest oxidation states, oxides to oxides of higher

oxidation or to peroxides, sulphides to sulphates, carbon to carbon dioxide

(even at normal temperatures), and ammonia in either the dry or gaseous

liquid states, of dissolved in carbon tetrachloride, to ammonium nitrate.

ozone does not react with ammonium salts. In the majority of oxidation

reactions, it is reduced to molecular oxygen releasing only one oxygen

atom. Ozone can react in three different ways with organic compounds, vis.

(I) a common oxidation reaction takes place, (II) peroxide compounds are

formed or (III) addition to double or triple bonds is brought about, with the

formation of ozonides, in many cases only as intermediates. Oxidation,

particularly at high ozone concentrations, can go as far as the formation of

CO2 and H2O. Usual concentrations, however, cause the formation of

substances containing more oxygen or less hydrogen from the original

molecule.

INTERACTION BETWEEN OZONE AND VARIOUS SUBSTANCES For materials

in contact with ozone two considerations apply. The first relates to the

extent ozone reacts to the materials in question, the second being

associated with the magnitude of the effect exerted by the material on

ozone itself to promote or catalyze its decomposition. Groups of materials

encountered in practice will be investigated below according to the two

view points referred to above. As has been shown earlier, most metals are

strongly oxidized by ozone. Corrosive action can be generally noted over 2

to 3 ppm., Particularly in the presence of moisture. Lacquering or other

surface treatments applied for corrosion protection can be beneficial to a

certain extent. Metals promote in most cases the decomposition of ozone,

some of the reactions being catalytic. Good catalysts are, for example, iron,

particularly if rusted, zinc, mercury, platinum and silver. According to

Yemelyanova et al, noble metals are the most active catalysts at low

temperatures. Kastanov et al, found that, all of the metals, pure aluminium

has the smallest catalyzing effect at low ozone concentrations and 373k.

Schumacher found aluminium acceptable at low temperatures even for the

stability of liquid oxygen-ozone mixtures, whereas, according to Lamneck

decomposition is slower under such conditions, for example, in the presence

of copper than in contact with aluminums Mahieux's investigations showed

that a room temperature and an ozone concentration of 7%, decomposition

of O3 is not assisted by pure lead, copper, or tin in addition to aluminums.

Stainless steel, besides anodized aluminium is suggested as a metallic

material for construction, particularly for applications involving low

temperatures and high ozone concentrations. In terms of chemical

resistance and stability of ozone, glass would be an ideal material for

vessels and piping. Owing to its low strength and lack of elasticity, however,

the use of glass is severely limited. For higher mechanical loads (due to

pressure for example) and increased ozone concentrations therefore, the

use of glass lined steel is being proposed. It is noteworthy that Waller and

McTurk found that bottles made of stainless steel with the inside surface

phosphate to be as satisfactory as glass. Minimum wall effect and maximum

half-life for the thermal decomposition of ozone were experienced with such

bottles. Due to their large specific surfaces, all absorbents such as activated

carbon, molecular sleeves, silica gel, activated aluminums, etc., act as

strong catalysts to assist the decomposition of ozone at room temperature.

In the case of activated carbon, oxidation also takes place, whereas the

pure absorption effect prevails in molecular sleeves because the catalytic

effect ceases on saturation. The catalytic effect of molecular sleeves for

preventing the decomposition of ozone can be well utilized in practice, e.g.

for the de Ozonization of tail gases containing ozone. Judging from the

investigations of Szabo a properly sized stainless steel reactor packed with

13X type molecular sleeves, is suitable for continuous de Ozonization at

room temperature, yielding an ozone free outlet stream even with ozone

concentrations in the inlet stream at the percent range. Due to the

exothermic decomposition the part of the catalyst bed, the state of which is

dependent on ozone concentration and flow velocity will be heated to a

temperature above ambient. Melted pure X-Al2O3 containing relatively large

pores has practically no catalytic effect on decomposition. The presence of a

small amount of metallic oxide inclusions, however, can initiate explosive

decomposition. Oxides of iron, cobalt, nickel, silver and manganese are

particularly active catalysts. Pure (CU O), in turn, has practically no effect

on ozone. Activity of catalysts is strongly dependent on their crystalline

structure, the presence and distribution of moisture and other factors. A

good catalyst for cracking ozone is soda lime, which is also used in practice

together with metallic oxides and the absorbents referred to above for the

removal of ozone from tail gases discharged into the atmosphere. Rubber,

which is used in practice as material for seals, pipes and other components,

like organic materials in general, reacts actively with ozone. Synthetic

rubbers have a superior resistance to ozone over natural grades. From

among plastics, fluorinated plastics can be used with advantage as

materials for seals, pipes and even general construction materials, due to

their resistance to the action of ozone and to their lack of catalytic action to

promote decomposition. For high ozone concentrations, use of PTFE and

polydichlorodifluorethylene is recommended. These plastics can be utilized

for coatings, e.g. for lining steel bottles used in the storage of concentrated

ozone.

BACTERICIDAL, STERILIZING AND OTHER EFFECTS IN LOWER ORGANISMS

The use of ozone for decanted in water purification was mainly due to its

toxic effects on micro-organisms found in water, effects which exceed those

of any other disinfectant. Experience has demonstrated that it destroys with

extreme efficiency the spores of molds, amoebae, and viruses, and bacteria

as well as various pathogenic and saprophytic germs. These microorganisms

represent a wide variety of species, genera and families.

Therefore, organisms were to be selected for further investigations which

would best represent typical pathogenic effects on humans and animals. It

was similarly the long and successful use of ozone that created interest in

its utilization as a general germicide and sterilizing agent and for

highlighting its advantages over the other germicides used generally for

water purification, primarily chlorine. Special importance can be attached to

investigations relating to the specific destructive power of ozone on

selected bacteria, including quantitative data and the mechanism of

sterilizing and germicidal effects. As is known, bacteria are microscopically

small, single-cell creatures having a primitive structure, and they take up

foodstuffs from and release metabolic products to the exterior and multiply

by division. The bacteria body is sealed off towards the exterior by a

relatively solid cell membrane. Their vital processes are controlled by a

complex enzymatic system to which macro-molecular organic compounds,

frequently containing phosphorus or sulphur, contribute. Viruses are

extremely small, independent particles, built up by crystals and

macromolecules. Unlike bacteria they multiply only within the host cell.

They transform the protein of the host cell, to a certain extent autocatalytic

ally, in proteins of their own. Germicides and sterilizing agents interfere

with the metabolism of bacterium-cells, most likely through inhibiting of

blocking the operation of the enzymatic control system. A sufficient amount

of oxidizing agent breaks through the cell membrane and this leads to the

destruction of the bacteria or virus. The free electrical charge of the cell

membrane constitutes in most cases a strong obstacle for the effective

operation of the disinfectant. Chlorine is known to enter into reaction with

water and the reaction products generated will have a distribution

depending on the pH of the water. Free chlorine and un dissociated HOCI

can penetrate relatively easily into the bacterium cell; penetration ,

however, is not so easy for the negative OCI (Hypo chlorite) ion. Therefore,

it is more difficult for chlorine to kill germs in an alkaline solution (pH > 7)

where dissociated OCI ions are in preponderance. The destruction rate of

germs depends in general, on the concentration, the number of bacteria in

unit volume and on the pH of the medium. The process of necrosis of

bacterium cells and the contribution of the penetration of germicides

throughout the cell membrane and the part played by the various reactions

taking place in metabolism have not been fully explored yet. On the basis of

considerations referred to above, and Bering in mind that ozone does not

react with water, it can be assumed that the free electrical charge of the

cells does not reduce the effect. Holluta and Unger showed that the

destruction rate of germs has no measurable dependence on pH. This fact

constitutes one of the major advantages of ozone over other disinfectants.

For comparison, the germicidal effect of ozone and chlorine on the basis of

experiments conducted by independent investigators is show in table 21.

For the experiments, the bacterium Escherichia coli was selected as a

characteristic indicator of contaminants stemming from feces found in

natural water. Despite the different circumstances, the better germicidal

effect of ozone can be inferred from the comparison. Kizhinov and Kozhinov

report, the bacterial action of ozone on the basis of measurements carried

out at one of the municipal water works in Moscow. Measurements carried

out by Fetner and Ingols indicated the need for higher ozone concentrations

and longer exposure times under approximately identical conditions.

Deviations can probably be contributed to changes in the technique used for

the analyzes and to differences between experimental conditions. The curve

for chlorine is logarithmic, however, the effect of ozone below a certain

critical concentration value is small, of zero, but practically all germs above

this level are destroyed. This effect is called all or none response and the

critical concentration is referred to as "flash point". The critical

concentration lies just at the level, generally between 0.4 and 0.5 mg dm

that produce a small amount of residual ozone in water. The threshold value

of 0.4 to 0.5 mg dm -3 was observed by several research workers in case of

the viruses of influenza and polio, certain coli form bacteria and the spores

of Clostridium botulinum. For water purification it is the residual

concentration which is the critical factor in controlling the destruction of

micro-organisms. At the beginning of the 1960's it was unanimously

established that ozone solutions, particularly in the presence of free ozone,

have a more rapid effect on viruses than attained by the action of chlorine.

Thus, viruses prove to be resistant to chlorine under certain circumstances

but, it is increasingly difficult to destroy them even by exposure to ozone.

In general, the various genera of the polio virus was used for the

experiments. Katzenelson et al put greater emphasis on the effect exerted

on viruses during their investigations since they are known to be more

resistant to disinfectants than bacteria. A noteworthy phenomenon of their

investigation was the two step process of inactivation. Period 1 lasts less

than 10 seconds at which time a kill rate of 99% is achieved. Period 2 runs

for several minutes to complete destruction. Ozone was applied at 7

intermediate levels between 0.07 and 2.5 mg dm -3 but the phenomenon

was independent of the changes in the concentration. According to Berg et

al the higher resistance of viruses is caused by the formation of clumps. To

establish the theory, a preparation of polio virus was subjected to

ultrasound of 100w for 2 minutes at 20mhz. Ultrasound caused the

breakdown of such virus clumps, which then became extremely susceptible

to ozone. The other interesting observation was that the susceptibility of

the virus to ozone exposure persisted for a long time, even after protracted

storage of the culture at 203K. The virus relocated to a storage temperature

of 258K, however, became resistant. To account for this phenomenon the

most acceptable explanation appears to be that a significant percentage of

the viruses form clumps. Sommerville and Rempel published data (referring

to results obtained in 1943 by Kessel et al according to which the virus was

inactivated within 1.5 to 3 hours at a residual concentration of 1 mg dm. At

the same time, Naumann stated in 1954 that a residual ozone content of

0.45 mg dm inactivated the polio virus within 2 minutes. As virus

transmission can take place in water, possibilities of inactivation had to be

more precisely determined to prevent infection from viruses. In France Coin

et al, investigated the inactivation of the poliomyelitis virus by ozone. They

attained a kill rate of 99.99% with residual ozone content of 0.3 to 0.4 mg

dm in water within 3 to 4 minutes. Gevaudan et al studied, under somewhat

different conditions and by various methods, the destruction of viruses from

the sabin species of the poliomyelitis III genus. They found that organic and

inorganic substances in water reduce the effects of ozone. In other respect

their findings were identical to those published by Coin et al in 1964.

American investigators studied a variety of typical micro-organisms to

determining the specific effects of ozone. These included Bacillus

Anthracites (which causes Anthrax in sheep, cattle, and pigs, but is also a

human pathogen), Clostridium Botulinum (its toxin paralyzes the central

nervous system, being a poison multiplying in food and meals), Influenza

virus, Bacillus Subtilis (hay Bacillus, it decomposes organic matter in soil

and water, but not pathogens). For the experiments an average ozone

concentration between 100 and 200 ppm. was used. Miller et al achieved a

full sterilization of the spores of Bacillus Subtilis by exposing them to 100

ppm. of ozone for 45 minutes. Mice were inoculated with type A toxin with

the bacterium causing botulism and cultures of egg with influenza virus. The

culture contained a maximum of 10 bacilli causing botulism which

represents the exact lethal dose for mice. An exposure of the culture for 30

minutes to ozone was generally sufficient for inoculated animals to survive.

In the case of the influenza virus the egg cultures remained negative during

the check examination. It was shown also for other micro-organisms that

they could be destroyed by the application of 1.5 to 2.0 mg dm -3 ozone.

Included in this class were the Klebs-Loffler Bacillus or Typhus Abdominalis,

that spreads typically by aqueous infection and causes Typhoid. This group

also contains the typical Staphylococci causing general inflammation as well

as the spores of niger known under the name of Black Mount. At present,

treatment at a suitable temperature is used for sterilization, but sterilizing

by chemical means was also suggested. Results obtained from a large

number of experiments carried out with water show that most probably

ozone is the only substance which can be used as a chemical sterilizing

agent to substitute for the effects of temperature. Ozone excites intense

light emission of Armillaria mellea, a luminescent basidiomycete, over the

concentration range of 75 to 500 p.p.m. investigated. Exposures running for

3 hours were not fatal for all of its species (269). This property favouring

ozone is caused by a pigment of melamine type because another species of

luminescent basidiomycetes have no such pigment was destroyed after an

exposure to 100 ppm. of ozone for 10 minutes. For the progeny of Vicia

faba, ozone causes chromosome aberration and its effect is twice that

observed by x-rays.

Excerpt from "OZONE", by M. Horvath, L. Bilitzky, and J. Huttner , Budapest, Hungry,

published 1985...