Atritor was approached by a UK Tea, Manufacturer to design and build a small scale Turbo Separator which could be installed inline with their tea bag packaging machinery.
The machine had to be capable of separating the tea from teabags diverted from the packaging machines during blockages to reduce downtime.
A prototype was installed on site and ran in conjunction with a tea packaging line resulting in the development of the new TS1260 Model Turbo Separator.
The recovered tea separated from the bags is clean enough to allow it to be fed back into the packaging line, with the separated bags being used for animal bedding.
Depackaging Feedstock for AD Success
Packaged food waste is a valuable commodity and a rich source of material for Anaerobic Digestion plants.
The main food stuff materials available are, packaged supermarket waste and kerbside collected kitchen waste which generally arrives in the dreaded biodegradable starch bags.
Starch bags pose their own problems to AD if not removed, they wrap around mixers, block pumps and screw conveyors and take up valuable space in the digesters. The bags will not break down in the digesters as they require air to degrade (aerobic). Depending on the environmental conditions and thickness, starch bags will take from 6 weeks up to 1 year to totally degrade. Farmers are not so keen to spread digestate, which include starch bags, because their fields initially gain the appearance of a landfill site prior to the bags decomposing. Starch bags are only made up of typically, 15% starch, the remainder is inorganic matter.
There are a growing number of machines coming onto the market professing to be the solution to the depackaging problem.
The majority of the depackaging equipment presently available are based on hammer mills or shredding machinery which shred the packaged food waste before passing it through a squeezing process. Shredding reduces all the material to a similar size, increasing the difficulty of separation at the next stage. The size of the screens fitted has a profound effect on the amount of packaging passing through with the feedstock and the quantity or organics carried over with the separated packaging.
The smaller the screen size the cleaner the feedstock and higher the organic material content of the separated packaging.
The amount of organics found in the packaged waste after separation is also effected by the size of the dry solids content of the organic fraction. The larger the size of the organic fraction in the waste will result in higher organic content in the separated packaging using this method of separation.
The organic carryover must be kept to a minimum, as not only are you losing it as a fuel source, you will also be paying to dispose of it.
With some packaged materials, the organic content found in with the packaging after separation was greater than 20% using this method of repackaging.
Shredding the materials prior to separation makes it more difficult to achieve the high separation efficiencies required by Anaerobic Digestion plants.
The greater the size difference achieved between the packaging and contents the easier it is to separate them efficiently.
The Atritor Turbo Separator is designed to open the packaging just enough to allow the contents to be removed. Keeping the size differential as large as possible between the packaging and the organic contents, allows high separation rates to be achieved using relatively low power when compared with the alternatives.
Both packaged dry and liquid materials can be efficiently separated using the Turbo Separator method of separation.
The Atritor Turbo Separator, utilizing centrifugal forces and the mechanical action generated by the paddle system damages the packaging just enough to achieve separation rates of up to 99% efficiency
The results taken from a sample of recovered material (feed stock) which had been separated from packaged mixed supermarket food waste using a TS3096 Turbo Separator system were as follows:
Total Sample size collected: 20kg
Analysed Sample Size: 1.272kg
Dry Matter Content: 16.84% (214.2 gram)
- Plastic Films > 5mm: 0.01% (0.0214 gram)
- Plastic Particles > 5mm: 0%
- Stones > 5mm: 0%
- Glass > 5mm: 0%
- Metals > 5mm: 0%
- Plastic Films between 2 mm & 5mm: 0.01% (0.0214 gram)
- Plastic Particles between 2 mm & 5mm: 0%
- Stones between 2 mm & 5mm: 0.03% (0.0642 gram)
- Glass between 2 mm & 5mm: 0%
- Metals between 2 mm & 5mm: 0%
- Inert material < 2mm: 0.51% (1.092 gram)
Total Inert Contents: 0.56% (1.199 gram)
The organics were removed from the solids content by dissolving and flushing the material in three separate stages which consist of three hour, four hour and six hour process periods to reveal the inert contents.
The analysis was conducted by a company independent from either Atritor or the Anaerobic Digestion Plant where the sample was taken.
Atritor have supplied over 80 Turbo Separator systems separating a wide range of packaged materials to Waste Companies, AD plants, Composting Companies, Rendering Companies, Animal Feed Companies, Food Manufacturers and Secure Destruction Plants.
The first TS42120 model Turbo Separator has recently been supplied to an anaerobic digestion company based in Canada; they are achieving separation rates of over 20 ton/hr of mixed packaged food waste.
A number of AD Plants using this depackaging technology already have or are in the process of achieving PAS110.