Europàisches Patentamt ê 0 098 753 ® European Patent Office (ÏÏ) Publication number: B1 Office européen des brevets EUROPEAN PATENT SPECIFICATION (§) Dateof publication of patent spécification: 11.03.87 ® Int. ci.4: A 23 K 1/00, C 05 F 3/00 (fi) Application number: 83303884.7 (g) Dateoffiling: 04.07.83 (H) Process of utilising animal and vegetable waste. (§) Priority: 02.07.82 GB 8219213 (73) Proprietor: NATIONAL RESEARCH 15.03.83 GB 8307046 DEVELOPMENT CORPORATION 101 Newington Causeway LondonSEl 6BU (GB) Date of publication of application: 18.01.84 Bulletin 84/03 ® Inventor: Edwards, Clive Arthur 1 Ashley Gardens (§) Publication of the grant of the patent: Harpenden Hertfordshire (GB) 11.03.87 Bulletin 87/11 74) Représentative: Percy, Richard Keith (fi) Designated Contracting States: Patent Department National Research DE FR GB NL Development Corporation 101 Newington Causeway London SE1 6BU (GB) (3) Références cited: US-A-2620 274 Patent Abstracts of Japan vol. 3, no. 65, 6 June 1979, Page152M61. m h- oo o> o o Note: Wïthin nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been m paid. (Art. 99(1 ) European patent convention). Courier Press, Leamington Spa, England. This invention relates to a process of utilizing animal waste, especially pig and cattle wastes, or vegetable waste solids, especially potato peelings. The term "animal wastes" used herein means waste comprising predominantly animal dung, urine, and water, as distinct from slaughterhouse or butchery waste comprising inedible parts of animal carcase. The very large amounts of animal wastes generated by farm animals constitute a double problem. Firstly, they must be disposed of without causing pollution, secondly considerable amounts of energy-rich resources are lost during their disposal. Moreover, many such wastes have very noxious odours and decompose only slowly. Traditionally, most pigs and cattle were loose housed on a deep layer of straw during the winter. The straw served to absorb dung and urine so that a solid farmyard manure could be forked out of the buildings, stacked and eventually spread on the land. Today about 50% of animals in the UK are kept in buildings using minimal amounts of straw, sawdust or sand for bedding. Dung and urine are handled as a semi-liquid slurry, often made more liquid by washing out the houses. This can be handled more easily but creates disposal problems. 84 million tonnes of cattle waste and more than 9 million tonnes of pig waste were produced in the UK in 1980. Most of these are currently disposed of on the land, mainly in the form of slurries. As these slurries are normally too viscous to be pumped, disposal is very labour-intensive. More recently a process of mechanical separation of slurry into a "solids" component with 18-22% dry matter and a liquid component with about 8% dry matter has been developed. This improves the uptake of nitrogen by plants when the solids are spread on the land and the liquid fraction can be readily sprayed on to land. Various commercial types of separator have been developed for this purpose. It has been estimated that only 50% of animal wastes are applied to land with regard to their value as a fertilizer. Thus, more than 50% of this valuable material is at present wasted. It has now been found that the separated animal waste solids, especially from pigs and cattle, are an ideal medium for growing worms and they process the waste into a valuable agricultural material useful as a plant food, soil conditioner or a plant growing substrate. Since the product has little odour and an appealing peat-like texture it is readily saleable. The very large amounts of organic wastes generated by the food industry constitute a double problem. Firstly, they must be disposed of without causing pollution; secondly considerable amounts of energy-rich resources are lost during their disposal. Moreover, many such wastes have highly noxious odours and do not decompose readily. A typical waste of this kind is that produced by the processed potato industry. The proportion of potato peelings generated by mechanical peeling devices is high, typically 15-20%. These peelings are malodorous and do not decompose readily. The solids can be sold as pig food at about £1-per tonne, but the cost of transport is prohibitive if pig farms are not close to the processing factory. Potato production in the UK has been increasing annually, so that the waste disposal problem is likely to increase in the 1980's. It has now also been found that solid vegetable wastes from peelings, especially potato wastes, can be processed by earthworms into a valuable agricultural material useful as a plant food or soil conditioner. This also is a product of low odour with an appealing peat-like texture, which can be sold. These processes are therefore a valuable'way of utilizing the wastes, turning them from being a largely unwanted and expensive nuisance into a useful commercial product and solving a vexing problem of waste disposal. The worms are composed of 60-70% protein, 8-20% carbohydrate, 7-10% fat and 2-3% minerals and are rich in vitamins. The worms bred in this material are therefore a valuable protein feed additive for fish-farming, or for pigs or poultry and they can be separated from the worked waste and sold for this purpose, thus giving a second useful saleable material from the wastes. The invention accordingly provides a process of decomposing a waste consisting of, or including a major proportion of, separated animal waste solids or of vegetable peelings waste solids, the separated animal waste solids being obtained by separation of a solids fraction from animal waste slurry, the waste to be decomposed having a pH of between 5 and 9, any ammonia content less than 0.5 mg/g and a water content from 65 to 90% by weight which process comprises introducing earthworms or earthworm cocoons, preferably of the species E. foetida, D. veneta, E. eugeniae or P. excavatus, into the waste and- allowing the worms to mature and breed therein at a temperature of from 15 to 30°C and break down the waste into a product of peat-like appearance. Optionally, most or substantially all the worms are separated from the peat-like material. They can then be killed and processed for use as a feedstuff (see later). It should be made clear that, although the product could be said to have some of the appearance of a potting compost, the process of the invention is not one of composting. In composting, the starting waste is predominantly anaerobic and becomes aerobic only slowly. The unseparated animal waste slurry as produced is anaerobic but, after the separation process, the solids fraction becomes rapidly aerobic and acceptable to the worms and, once established the worms accelerate this process, by making air passages in the material and passing it through their intestines which increases the activity of aerobic microorganisms. The breeding of worms in waste has previously involved mixing the waste, usually sewage sludge or horse manure, with a bulking medium such as straw or wood shavings and letting this become aerobic by composting. Here it is the practice of separating solids from liquids that makes the waste acceptable to the worms. It is also distinct from ordinary garden composting, normally practised in heaps and using dead plants, grass and household organic wastes. The pig and cattle solids separation process produces a medium (78-82% by weight water, 18-22% by weight solids) which resembles that of worms (20-25% by weight solids) in terms of moisture content and thus places no osmotic or other stress on the worms, which probably accounts to a considerable extent for the success of the invention. The separated solids make an open medium that becomes aerobic rapidly with a minimum of composting necessary. Although the worms tolerate a wide range of moisture content in the waste, normally 50-90% by weight, they grow much faster and process organic waste much better at a moisture content in the waste of 65-90% by weight, the exact optimum range depending on the species of worm. The vegetable waste starting material is also solid, in the sense that it is capable of being handled as a solid. The potato processing industry also creates a liquid sludge containing only about 2-8% by weight of solids. This is not suitable for treatment in this invention as the water content is too high to create the areobic conditions necessary, and for the worms to breed optimally. The peelings produced have a water content of around 77% by weight, which does not normally vary by more than 1 or 2%. Again this particular water content (say 75-79% by weight) is very similar to the water content of most earthworms and it is quite possibly this factor which makes the peelings waste so outstandingly suitable for use, without pre-treatment, in the process of the invention. By contrast, many other wastes require a pre-treatment for vermicomposting. The water content should not normally exceed 90% and preferably not exceed 88% by weight. A range from 65 to 90% is preferred, the exact optimum range again depending on the species of worm. Worms can be grown satisfactorily in either kind of waste in boxes or crates lined with polythene with no additions of water from the beginning to the end of the process.