Garbage disposal unit

A Küchenabfallzerkleinerer (KAZ ) is a, particularly in the U.S. and Canada widely used device for comminuting organic kitchen waste. With its help, biodegradable waste is shredded from private households and small businesses for the transport through the sewers to the treatment plant. These can then be converted into digesters for sewage gas.

• 7.1 counterarguments
• 7.2 arguments of the proponents

General

The waste is in running water is finely divided in Küchenabfallzerkleinerer by the motor, and transported as sewage through the public sewer to the sewage treatment plants. The required transport work is done while the wastewater itself

The first Küchenabfallzerkleinerer in 1927 invented by John Hammes in the U.S. and brought in the following years of his company founded in 1938 on the local market. The number of deployed shredder is estimated in the United States at about 75 million to about 120 million worldwide.

Features and Function

The units are about 30 cm high, have a diameter of 15-20 cm and are installed between the sink drain and the siphon below the kitchen sink and operated at normal line voltage. The water drainage is ensured even when the device; For example, when using the sink.

By the sink drain kitchen scraps fall on a rotating disk mounted on the small, portable hammers, pressing waste by centrifugal force against the wall (about 5 mm in diameter) they crush the small sharp-edged holes until they through this be flushed down the drain. Long-fiber food waste (such as leeks or banana peels ) Some devices can only cross-cut process trouble free.

The turntable typically rotates at 1400-2800 rpm. The power consumption of the motors moves 200-1000 watts.

Legal situation

In the EU KAZ can be allowed. Thus in EN 12056-1 Chapter 4, paragraph 6: "The demands on the quality and volume flows of waste water, which is directly discharged into the public sewer system, are subject to national and regional regulations and technical rules and must be followed. The penetration of substances into the plant, which interfere with their effectiveness or which are not approved by the competent authorities is to prevent. National and regional regulations and technical rules may permit the use of Abfallzerkleinerern ".

In Germany, such approval as well, mostly rejected in many EU countries. DIN 1986-100, No. 6.5 dated October 2001: " Grinding Equipment for kitchen waste, garbage, paper, etc., and towel dispenser with flushing device in which the crushed ware can pass into the drainage system must not be connected to the sewage system, " however, is the not mentioned device in the succession plan 12056. In Germany there are no national ban, prohibit individual communities but waste, whether crushed in their Wastewater Ordinance. In Switzerland, the local waste water regulations normally prohibits the use also.

Dissemination

Küchenabfallzerkleinerer be used worldwide, mainly known they are in the USA. In Europe they are explicitly allowed in the following countries:

• Great Britain: citizens get in some municipalities grants for the purchase of Küchenabfallzerkleinerern.
• Ireland
• Norway
• Sweden
• Denmark
• Spain
• Italy

Practice

In particular, the decades- long practice in the U.S. has shown that normal kitchen waste pipes with diameters of 40-50 mm are perfectly adequate. The waste water correctly unused KAZ differ with their increased proportion of food waste in their viscosity not particularly from those of conventional flushing sewage.

Arguments of the proponents

Because of the construction and functioning are Küchenabfallzerkleinerer usually only able to process biodegradable waste. This access method requires no impurities in addition to the organic waste into the sewage system. In contrast, provide illegally deposited impurities (mainly packaging, metals, etc. ) in special fermentation plants for the waste from waste tons a major cost factor dar. This problem does not occur with an introduction of biowaste by chopper.

Fricke in 2003 and in the years before detailed studies on the domestic disposable behavior. As a result, the proportion of organic waste was found in the trash at 33-51 percent by weight. The proportion of organic waste have also reduced by the compost bin only to 27-39 % and form still the largest proportion of residual waste.

Kitchen waste consists of up to 90% water, so it stands to reason to dispose of together with the waste water. Furthermore, it is widely practice that - despite ban - organic kitchen waste is disposed of through the toilets. A previous shredding here is an alternative as crushed particles are processed better by the treatment plant. So anyway as human waste and toilet paper composted in the digester and the digester gas be converted to electricity, other organic waste to come.

An attraction of rats is not to be feared, since rats only accept certain food consistency and size. Scientific studies and decades of practice in the United States also show that it is possible to contain the rat populations through the use of KAZ because the animals a part of the food source is removed. The bigger problem in line blockage is known to the water installers: deposited fats that are cool to the conduit wall and become hard, can only be removed mechanically. The additional, albeit tiny solids create the contrary, an additional degree of abrasion.

Since mid-2005 the landfilling of untreated waste in the EU is largely prohibited. In Germany therefore hardly takes place a landfill. The so-called residual waste is burned. With the help of KAZ, the volume of residual waste could be reduced greatly. Furthermore, it is hoped that significant cost benefits for the citizens, because the disposal costs of the compost bin largely omitted or would be reduced and the operation improved in the treatment plants.

In particular, allergic or other health predisposed people have with a KAZ the way to prevent the inevitable occurrence of mycotoxins from the beginning, because the unwanted organic material is removed immediately ( see also compost bin ).

Many wastewater treatment plants suffer from a bad C / N ratio and the effluent must admit for obtaining any necessary by law limits for nitrogen carbon, so that denitrification can be performed. Today, this is generally achieved by the addition of expensive external carbon source such as methanol, glucose, acetic acid, etc.. By carbonaceous kitchen waste to the treatment plant saves the effort. Therefore, some wastewater treatment plants with a high content of nitrogenous waste in the urine have been transferred to zuzukaufen external kitchen waste and this crushed add the wastewater.

Advantages over the composting of organic waste

Moisture organic waste are not well suited for composting because inevitably form in the compost windrows during the composting anaerobic zones where large amounts of greenhouse gases (mainly methane). Why rent ( eg, diesel fuel for the tractor ) must be up to 30 times play during composting using fossil fuels. For drum plants electrical energy is used. The cancellation of the compost bin brings an immediate saving of around 50 euros per year on average.

Production of biogas ( sewage )

With increasing tendency, the so-called co-fermentation is also operated in German sewage treatment plants, ie decomposable wastes with high water and sufficiently high energy content are fermented together with the sludge from the primary clarifier in the digester. The biogas ( called in sewage treatment plants sewage ) with a high methane content is converted into electricity in the plant uses the heat for heating the building and operating digesters.

However, in practice in Germany from a few exceptions (such as the municipal wastewater treatment plant Baden Baden) hardly biowaste as a co- substrate used, but mainly separately delivered and pretreated materials. The decades- long, very successful practice of co-digestion of kitchen waste in the United States shows that a fermentation in other countries would be possible.

As experience from the operation of agricultural biogas plants showed the processing of a mixture ( co-digestion ) is from normal household waste water and shredded biowaste significantly more stable to operate than a conventional mono-digestion. Fermentation plants for biowaste have often struggled with the composition of the fermentation substrate, which is evidenced by fluctuating gas revenues. The supply always new bacterial cultures from the waste water stabilizes the degradation processes and ensures a constant gas production.

In contrast to conventional composting, which such as methane comes up mainly due to the inevitable production of highly potent greenhouse gas with a very poor carbon footprint, the average energy content of 3.9 MJ per kg of kitchen waste can be part of the co -digestion in the digester of the WWTP make it usable.

In the latest amendment to the Renewable Energy Law, the current generated from sewage gas in sewage plants is far less well paid than eg biogas from maize silage or green. This is a disadvantage of using this renewable resource and also that the investments of the citizen in the area-wide sanitation worth about two trillion euros can not be used to the extent necessary for power leads.

Counter-arguments and responses

Counterarguments

Through the incorporation of additional organic waste, the inflow of the wastewater treatment plants with organic material increases. In many cases, the equipment for these additional amounts are not designed. An enlargement of the plants just because of biowaste would be required, but not economically viable. It is also shown as economically questionable, inflicting only solid wastes expenditure of energy and drinking water to the waste water in order to separate the other hand, within the wastewater treatment plants. Due to mixing with other substances no more then quality recycling is possible.

Also brings before you, were formed in the duct system reinforced deposits. These increased maintenance. As in Germany, about half of all duct systems was still designed as a mixing system for rainwater and wastewater, it would apply in heavy rain events there in an additional discharge over the spillways directly into the receiving water. In separation systems were it not for this effect.

In addition, the compost bin would be through the introduction of Küchenabfallzerkleinerern not ultimately superfluous as garden owners took advantage of this for garden waste.

Incinerators are dependent on a constant calorific value of the waste. It should be rather less than more, because otherwise the combustion temperatures rose too strong and therefore decreases the service life of costly grates. A large part of what was burned in the plants, would consist of packaging, plastics, and paper and paperboard. A mixture without the wet kitchen waste meadow on an energy content of 25 and more MJ / kg and was therefore too high. The wet kitchen waste made ​​for a system acceptable value. Contrary to popular belief, the proceeds usually played on the sale of heat and electricity in the calculation of a waste incineration plant not matter, but rather the maintenance costs, eg the fire grates.

Arguments of the proponents

The requirements of EN 12056-1 are prohibitive. One wants to avoid, among other things, that the lucrative disposal of biowaste through the system of "Bio- ton ", "green bin" or " brown bin" be withdrawn. Stood the kitchen garbage here no longer available, the question arose concerning the existence of expensive fetching system of domestic organic waste, which is financed by the waste disposal charges of the citizen.

2007 about 6 million tonnes of organic waste were collected nationwide, for which the citizens were charged at an average cost of 100 EUR / ton with fees in the amount of approximately 800 million euros. When used by KAZ those transactions would greatly diminished. Citizens would not only save waste charges, sewage charges could also drop, since in many cases, treatment plants could be energy self-sufficient because they used the energy from the organic waste.

Swell

• Food processor
• Waste Management