On 2.: Biological- mechanical treatment in a three- phased process
Besides scrap plastics and rubber products the BKB catalogue (see above, www.eon-energyfromwaste.com ) contains waste of biological origin which, however, is highly contaminated, e.g., with technically produced colors, coatings, impregnations, salts of haevy metal or even enfectious pathogenes, e.g., in hospital waste.
We can entrust such contaminated biowaste ( http://en.wikipedia.org/wiki/Biowaste / http://en.wikipedia.org/wiki/Organic_waste ) to the cleaning work of microorganisms ( http://en.wikipedia.org/wiki/Microorganism ). They have practiced this about three billion years longer than we do. They allways have been successful, too. We often have had to rely on microbes in the hope of having an industrial wasteland recultivated or the ocean renaturalized after a tanker accident ( http://en.wikipedia.org/wiki/Tanker ).
We must, however, control them with microbiological expertise so that they can deliver these results quickly enough.
The Eikmanns criticize the existing BMT plants, which they call MBT- plants, in the article ( 21 ) quoted earlier. Their exact words:
"In Germany their are about 48 MBT- plants in operation today with about 5.1 million tons treatment capacity. .... The realized egineering concepts are very different and as a whole not easy to compare. Despite partly very costly exhaust air cleaning systems, ever since these plants were put into service offensive odors in the neighborhood of many MBT plants have bees a cause of considerable nuisance to the population, leading to massive protests of the residents. Biogas, landfill gas ( http://en.wikipedia.org/wiki/Landfill ), the air from the treatment and percolation sheds, the biostabilized output called Geostabilat, but also the dumping areas can be classified as relevant emission sources for the odors ( http://en.wikipedia.org/wiki/Odor ). Mainly composting activities (partly in decay sheds) and disposal and transfer processes of material from the landfill area come into questions for the release of bioaerosols. ( http://en.wikipedia.org/wiki/Aerosol )
And they continue:
"A health risk to the population in the sence of a higher frequency of symtoms, syndroms or deseases can very probably be ruled out for residual areas in the vicintity of mechanical- biological plants (MBT).
The nuisance ( http://en.wikipedia.org/wiki/Nuisance ) caused by the odors occurning in the vicinity of MBT plants are described as exremely unpleasant by the population - and according to the hedonic criteria ( http://en.wikipedia.org/wiki/Hedonic ) According to the GIRL ( odor emissions guidline) assessment criteria they constitute per se a "risk to health" and are basically to be avoided."
An accompanying illustration shows a girl who obviously is about to become nauseous.
This negative assessment of the MBT plants seems to be as tendentious to us as the one- sided praise if waste incineration plants (WIPs) in the same article ( http://en.wikipedia.org/wiki/Incineration ).
Of course, MBT/BMT- plants shouldn´t stink. But that doesn´t have to be. If residents complain about this at existing MBT plants, these plants are neither expertly disgned nor correctly dimensioned. Perhaps these plants are designed for a catchment area which is too large, and they are not able to properly process the accumulating waste. Perhaps they are more similar to large compost piles than to technical plants. As we conceive it, the BMT plant, too, follows a techncally controlled concept and has nothing more to do with large compost stockpiles. ( http://en.wikipedia.org/wiki/Compost )
* Dr. Rosins BMT- concept
The contaminated organic waste are immediately channeled into a closed system consisting of three rotary tube reactors. In these rotary tubes the waste is constantly in motion. The three- phase treatment thus can be finished in 12 to 14 days. The bulk of what comes out is equivalent to ripe compost which smells like forest humus.
Each BMT unit consists of three rotary tube connected in series, which are alternately operated in aerobic mode, then in anaerobic mode, then again in an intensive aerobic mode. Such a line or several lines in a parallel could be established on one site. In any case a biofilter on each reactor ensures that the reactors`gaseous emissions are made reliably odor- free. Slaughterhouses have proved that this is possible: they keep their sheds odor-free with the help of biofilters so that no nuisance is created in the neighborhood. Incidentally residents in the near vicinity of WIPs also occasionally report pungent odors.
* Differences from BMT and WIP
Much more important is that we remember the fundamental differnces between the material transformation in WIPs (also HWIPs) on the one hand, and BMT plants on the other:
----in the WIP the substances are heated to high temperatures, consuming very large amounts of atmospheric oxygen ( http://en.wikipedia.org/wiki/Oxigen ). The heating effect degasses them. It tears most molecules into fragments of molecules ( radicals / http://en.wikipedia.org/wiki/Radical ). These radicals search for reaction partners in a chaotic way to become completed again. Innumerable problematic substances and toxins emerge through the chaotically proceeding de novo synthesis during the cooling phase, and they "poison" all residues from WIP ( http://en.wikipedia.org/wiki/Poison ). In the slag ( http://en.wikipedia.org/wiki/Slag ) they are in the gas- filled pores. Otherwise they adhere to the toxically laden dust ( http:/7en.wikipedia.org/wiki/Dust ) and soot particles ( http://en.wikipedia.org/wiki/Soot ). Waste which had been use- freindly a short time ago emerges "poisoned" from WIP. Nothing that leaves the wip is still "inert"!
In the BMT plant, in contrast , the atmospheric oxygen and the water in the waste mainly serve as medium of life for the substances´microbial conversion.
In the first stage aerobic decay, just enough heat is produced as it is necessary for "hygienization", about 70°C. This temperature kills all vegetative, i.e., directly infectious, human pathogens. This is enough for "hygienization". The slowly revolving rotary tube reactors, in which resistors, so- called baffles, permanently circulate the waste, expose the microorganisms in the reactor to always new nutrients. this permits completing aerobic decay including hygienization of waste within two days.
As second stage anaerobic fermentation then follows. Here special emphasis is placed on detoxification ( http://en.wikipedia.org/wiki/Detoxification ) as well as dehalogenation ( http://en.wikipedia.org/wiki/dehalogenation ) and mobilization of heavy metals ( http://en.wikipedia.org/wiki/Heavy_metal_%28chemistry%29 ). Lower reaction temperatures of about 30°C must prevail in the reactor ( 40 ) ( 42 ) to make enzyme systems work which enable the anaerobic bacteria to dehalogenate and detoxify. This can be controlled in the reactor. At the end of anaerobic fermentation the part of the reactor contents which is enriched with heavy metal salts will be routed in a shunt through an innovative biosorption reactor. There the heavy metals will be collected in an easily smeltable concentration. Everybody knows, since the disaster of the nuclear MCA of Chernobyl at the latest, that mushrooms and certain bacteria are able to accumulate heavy metals. For years afterwards - actually until today - it was forbidden to gather forest mushrooms in the fallout zones. The salt ellimination is a missing in current MBT plants. This is a much bigger hygienic disadvantage than perhaps odor problems. (The text forgets the winning of Biogas at this step! F.St.)
As third stage after salt elimination and anaerobic detoxification, once again an intensive decay phase follows. It is designed to decompose also lignin ( http://en.wikipedia.org/wiki/Lignin ) and humic substances ( http://en.wikipedia.org/wiki/Humin ) with activated oxigen ( http:/7en.wikipedia.org/wiki/Activated_oxygen ). So that enclosed toxins (http://en.wikipedia.org/wiki/Toxin ) will be made harmless by oxidation ( http://en.wikipedia.org/wiki/Oxidation ). After that the biggest part of the biolocial/ organical waste meets the requirements of ripe compost of the best RAL quality category. It has been really been made "inert", and the waste as a whole is sufficiently reduced in volume. Only a smal rest, e.g., residues of lignin and leather, have to be decomposed by fungi cultures. These cultures need to be left alone to do their work. This can be made possible in encapsulated longtime decay devices. Biofilters prevent any odor emissions ( http://en.wikipedia.org/wiki/Biofilter ).
The commercial explotation of larger quantities of compost should not be a problem. For the Medeteranean area, but also for Germany and many other regions of the world, heavy downpours and longer dry periods are predicted to cause considerable problems for our agriculture. To compensate these anomalous conditions for farming as well as possible, much compost will be needed as soil conditioner and as outstanding rainwater reservoir ( 63 ).
( 21 ) eikmann, Th., S. Eikmann: Machen (Makes) MVA (WIP), MBA (MBT) und SVA (HWIP) die Menschen krank (the humans ill)? RECYCLINGmagazin, 24-25 (2008)
( 40 ) Leahy, J.G., R. Colwell: Microbial Degradation of Hydrocarbons in the Environment. Microbiological Review, pp 205-315 (1990)
( 42 ) Lovely, D.R., J.C. Woodward: Consumtion of Freons CFC-11 and CFC 12 by Anaerobic sediments and Soils. Environmental Science & Technology 26, 925-929 (1992)
( 63 ) Seifert, A.: Gärtnern, ackern - ohne Gift. Biederstein Verlag (1973)
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