METHOD FOR NEUTRALIZING AND REGAINING OF GASES BEING RELEASED BY WET COMPOSTING OF DOMESTIC ANIMAL MANURE AND SEWAGE AND SIMILAR MASSES, AND ALSO INSTALLATION FOR CARRYING THE METHOD INTO EFFECT

Abstract: The invention relates to the neutralization and controlled recovery of environmentally harmful or polluting manure gases and sewage gases which are released during wet-composting of manure from domestic animals, sewage mud, or similar masses. It also relates to the return of such released gases to ready composted manure, sewage mud or similar mass in order to produce an improved fertilizer. To this end, manure gas (5) or sewage gas released during the wet-composting process is atomized and conducted into ready-composted manure (7) or sewage mud. In a wet-composting plant for carrying out this method, a first basin (1) (the fermentation basin) is sealed so as to be gas-tight. In this basin, the gas space above the manure (3), sewage mud or similar mass communicates with a second basin (6) containing ready-composted manure (7), sewage mud or similar mass. Thus, manure gas or sewage gas is conducted into the mass in the second basin where it is atomized and mixed into ready-composted manure, sewage mud or similar mass.

Description: METHOD FOR NEUTRALIZING AND REGAINING OF GASES BEING RELEASED BY WET COMPOSTING OF DOMESTIC ANIMAL MANURE AND SEWAGE AND SIMILAR MASSES, AND ALSO INSTALLATION FOR CARRYING THE METHOD INTO EFFECT The present invention relates to a method and a plant for neutralizing and recovering gases, socalled manure gases respectively sewage gases or the like formed and released when wet composting manure from domestic animals respectively sewage mud or similar masses. The invention aims at partly to render harmless harmfull, toxic and/or polluting manure gases and sewage gases and similar by preventing respectively reducing their concentrated outlet into the atmosphere, partly to return the gases to a finnished composted mass for increasing the nourishing value thereof as manure. Thus, composted sewage mud and similar masses are in this connection called manure and are used as such. Manuring with composted manure, sewage mud or similar masses admixed manure gases respectively sewage gases and the like will reduce the need for artificial fertiliser in a not inconsiderable degree. Manure gas and sewage gas are hereinafter used as common terms for the gases here in question. Thus, manure gas and sewage gas consist of a large number of various gases wherein carbon dioxide, methane, ammonia and hydrogen sulphide are the dominating. The absolutely most dangerous manure gas constituent is hydrogen sulphide (confer manure gas poisoning). Ammonia is usually released in relatively harmless concentrations. However, released ammonia will increase the poisonous effect of hydrogen sulphide when the two gases appear together. Manure gas and sewage gas are formed in organic material which is demolished under socalled anaerobic conditions, i.e. without access of air. A typical material in this connection is wet manure. The gas is present within the manure partly in the form of small gas bubbles, partly dissolved in the manure liquid. As long as the manure rests, very little manure gas is released; it is first when the manure comes into motion that manure gas is released and rise. Aerobic fermentation of e.g. manure from domestic animals, socalled wet composting, is effected through continuous or intermittent supply of oxygen to the wet manure. In practice the process involves air admixture during vigorous stirring of the manure, causing a strong increase of temperature and fermentation. Within the raw material, the wet manure, it has already prior to initiated aerobic fermentation been formed some manure gas in' dissolved state as well as in the form of small gas bubbles. The gas is released as soon as the manure is put into motion. It is manure gas respectively sewage gas released through wet composting of manure from domestic animals respectively sewage mud and similar masses which are intended neutralized and recovered by means of teh invention. In order to mix air into e.g. wet manure with wet composting within manure basin, it is known to use an immersed injector through which the manure is pumped using great force. This causes a vigorous stirring of the manure in the basin and provides admixture of air. The air supply and the air admixture are attended to by the nozzle of the injector. This is assigned an air inlet pipe which opens above the manure surface. The through-pumping of manure creates sub pressure conditions at the injector nozzle, which thereby through the air inlet pipe sucks air into the manure stream, which is spraid into the manure basin. This efficient through-airing of the wet manure gives, in combination with the -stirring, rise to a a favourable temperature increase and acceleration of the fermentation process, causing a shortening of required fermentation time. In conventional wet composting technique, no measures whatsoever have been effected, neither to neutralize released manure gas nor to recover the same for utilization within the finnished manure product. Thus, from a pollution point of view as well as from an ecological and economical point of view there exists a need for a method and a plant of the kind defined introductorily, wherein controlled neutralisation and recovery of manure gases respectively sewage gases have been provided. The object of the invention is to satisfy these needs. Composted manure from domestic animals respectively sewage mud or similar masses containing manure gases respectively sewage gas in dissolved form and in the form of a very large number of tiny gas bubbles will represent an ecologically very good fertilizer and soil amelioration agent which in a substantial degree will reduce the need for completing supply of artificial fertilizer. The object of the invention is achieved proceeding in accordance with claim 1. Suitable plants for carrying out the method are defined through the features of the subsequent claims. Thus, the invention consists substantially in taking care of manure gas respectively sewage gas released during wet composting of manure from domestic animals respectively sewage mud and similar masses and mix this gas into a finnished composted or substantially finnished composted manure from domestic animals respectively sewage mud and similar masses during a manure respectively mud stirring and gas injection process. A plant for carrying ojut this method must comprise at least two basins, one for fermentation of raw manure from domestic animals respectively sewage mud or similar mass and one for admixture of manure gas respectively sewage gas released in the first basin, into finnished or substantially finnished composted manure respectively sewage mud or similar mass. The first basin, the fermentation basin, must be gas-tightly closed, so that released manure gas respectively sewage gas does not escape. When the process starts, finnished or substantially finnished composted manure from domestic animals respectively sewage mud or similar mass must be provided within the second basin. Then, when this mass has been supplied and admixed released manure gas respectively sewage gas from the first basin and, thus, has been converted into the desired fertilizer, this may be removed from the second basin, which thereafter may be filled with manure respectively sewage mud or similar mass from the first basin as soon as this is finnished or substantially finnished composted. The treatment of the manure respectively the sewage mud or similar mass will take place intermittent. Suitable wet composting plants for carrying out the invention may -be subjected to many constructive modifications within the general scope as defined in the following claims. Thus, it is e.g. possible to use a separate stirrer in order to put finnished or substantially finnished composted manure respectively sewage mud or similar mass into motion during the manure gas respectively sewage gas admixture, which in such a case is effected by means of a separate gas injection means. The stirring respectively injection function of these means is, however, preferably effected by a single means, e.g. in the form of a submerged injector having a manure gas respectively sewage gas supply pipe. Further objects, features and advantages beyond those described in the foregoing will appear from the following specification, reference being made to the enclosed substantially diagrammatical drawing figure illustrating examples of two embodiments of wet composting plants in accordance with the invention and representing a principle sketch for the method according to the invention, and wherein general features of plants of the invention appear. The examplary embodiments relate to wet ςomposting of manure from domestic animals in basins. In the left basin in the figure of the drawing, later called the first basin 1 because the process starts here, aerobic fermentation takes place in known manner, air being supplied through a pipe 2 and conducted into the manure 3 through a submerged injector 4, such as .described in the foregoing. As mentioned, the manure 3 is subjected to vigorous stirring movements during admixture of air; this causing a rise of temperature within the manure and an acceleration of the fermentation process, whereby manure gas 5 is released. The first basin 1, the fermentation basin, is gas-tightly closed by a cover 1 ' . The wet composting plant comprises also a second basin 6, which in two alternative embodiments may be upwardly open or gas-tightly closed by a cover 6' (dotted lines). In the second basin 6, finnished or substantially finnished composted manure 7 has been placed. The first basin 1 and the second basin 6 are uppermost mutually connected by means of a manure gas transfer pipe 8 for the transfer of manure gas 5 from the first basin 1, -the fermentation basin, to the second basin 6, or more specifically to an injector 9 submerged into the manure 7. According to the embodiment shown, the manure gas transfer pipe 8 has a vertical downwardly directed portion 8 ' , and this portion 8 ' is with its lower end connected to the injector 9, which may have the same general construction as the injector 4 within the fermentation basin 1. The injector 9 within the second basin 6, the manure gas admixing basin, serves to spray supplied manure gas, finely powdering the same, into the finnished or substantially finnished composted manure 7 and, thus, supply valuable nourishing substances to the finnished manure. Simultaneously, manure gas released during the fermentation process is rendered harmless, concentrated outlet of manure gas being made impossible. The plant may possibly comprise a third basin 10 (dotted lines) having an injector 11. The third basin 10 which may be filled with water 12 admixed e.g. lime - or the basin 10 may be filled with another suitable liquid - communicates with the gas space 6" of the second basin 6 through a gas transfer pipe 13. The purpose of this arrangement is that any surplus gas from the basin 6 shall have the possibility of flowing further to the third basin 10 for admixture into the lime water 12 by means of the injector 11. The use of such a third basin 10 has in some cases been found to give improved results through optimal utilization of manure gas 5 released in the fermentation basin 1. Thus, the nitrification process which hithertofore only could take place within the soil, may now take place in a basin.

Claims: C l a i m s 1. A method for the neutralization and recovery of gases, socalled manure gases respectively sewage gases, released when wet composting manure from domestic animals respectively sewage mud or similar masses, c h a r a c t e r i z e d i n that manure gas (5) respectively sewage gas released during the wet composting process is conducted into finnished or substantially finnished composted manure (7) respectively sewage mud or similar mass, and finely powdered therein, the manure gas (5) respectively the sewage gas or substantial constituents thereof being retained within the finnished or substantially finnished composted manure respectively sewage mud or similar mass. 2. A plant for carrying out the method as defined in claim 1, comprising a first basin (1) for wet composting manure from domestic animals respectively sewage mud or similar masses, releasing manure gas (5) respectively sewage gas, c h a r a c t e r i z e d i n that the first basin (1) is gas-tightly closed ( 1 ' ) , the gas space thereof above the manure (3) respectively the sewage mud or similar mass communicating with a second basin (6) for finnished or substantially finnished composted manure (7) respectively sewage mud or similar mass, for supplying manure gas respectively sewage gas to the manure (7) respectively the sewage mud or similar mass within the second basin (6). 3. A plant as set forth in claim 2, c h a r a c t e r i z e d i n that gas transfer pipe(s) ( " 8,8') from the gas space of the first basin (1) lead(s) to an in per se known submerged injector (9) in the second basin (6). 4. A plant as set forth in claim 2 or 3, c h a r a c t e r i z e d i n that the second basin (6) is gas-tightly closed (6' ), and that the top space (6") thereof, serving as gas space, communicates with a third basin (10) containing water (12) or another liquid, for receiving any residual manure gas respectively sewage gas into the water (12) or another suitable liquid in the third basin ( 10 ) . 5. A plant as set forth in claim 4, c h a r a c t e r i z e d i n that pipe(s) (13) from the gas space (.6") ' of the second basin (6) lead(s) to an in per se known submerged " injector (11) within the third basin (10).

Inventors: TEGLE SVEIN, TEGLE, SVEIN
Applicants: TEGLE SVEIN, TEGLE, SVEIN
Application year: 1992
Main classification: C05F17
IPC codes: B01D53, C05F17