US2175300A - Method of destroying sewage - Google Patents

Description

Oct. 10, 1939. H. H. MORETON METHOD OF DESTROYING SEWAGE Filed Aug. 2, 1935 2 Sheets-Sheet 1 Oct. 10, 1939. H. H. MORETON METHOD OF DESTROYING SEWAGE Filed Aug. 2, 1935 4 2 Sheets-Sheet 2 Tjjji: 75

55 the chamberl0.

Patented Oct. 10, 1939 PATENT OFFICE 2,175,300 I METHOD OF DESTROYING' SEWAGE Henry H. Moreton, Santa Monica, Calif. Application August 2, 1935, Serial No. 34,481

8 Claims.

This invention is a method and apparatusfor effecting complete destruction of sewage.

The effective destruction of sewage without soil or water pollution has long been a serious probe lem. In fact, attempts heretofore made to physically destroy sewage have met with indiiferent success from the standpoint of practical economy, and convenience and complete sanitary safety in handling, and so that at the present time, the so-called bacterial systems are considered the safest and most desirable methods for municipal installations. A system of the last-mentioned type, however, involves the installation of apparatus which must be spread over a considerable area, requires a very large investment to meet the initial cost of installation, and is more or less expensive to operate.

One of .the objects of the invention is to pro-j vide for complete and economical physical de-' struction of sewage by incineration, whereby practically no residue is left, so that thepossi bility of either soil or water pollution is reduced to the absolute minimum. A further object is to provide for complete incineration of sewage in such manner that the discharge of objectionable and offensive odors, smokes and gases into the surrounding atmosphere is prevented. A further object is to pro-vide a system of low installation cost and highly economic operation, capable of providing for initial dehydration of thesewage and subsequent complete incineration in a continuous process. A further object is to employthe' caloric values inherent to the sewage being treated, to assist in the incineration of the material being treated, after its dehydration.

The invention will be hereinafter fully set. forth and particularly pointed out in the claims.

In the accompanying drawings:

Figure 1 is a vertical elevation more or less diagrammatic in character, illustrating an apparatus constructed in accordance with the invention, certain parts being shown in section. Figure 2 is a detail sectional view of a portion of one of the rotatable furnaces. Figure 3 is a side elevation diagrammatically illustrating a modification.

Referring to the drawings, I designates a combined dehydrator and incinerator, which consists of a relatively long cylindrical chamber In, rotatively supported in a longitudinally inclined position, a well known manner, by suitable bearings ll. may be efiected by any suitable means, such as a gear l2 engaging a gear-ring l3, which encircles The higher end of said cham- Rotation of the cylindrical chamber berlfl' projects into a receiving chamber l4, through the top of which extends an inlet chute l6.f a

- The open lowerend of the cylindrical chamber It extends into a burner box 20, into which is projectedone -or more burners 2| for gas, oil, or the like,,the delivery ends of the burners being directed axially toward the incinerator I, in such manner as to project the flame into the open lower end of the latter. The burner casing rests upon a suitable platform 22, onto which the chamber [0 deposits the material which is discharged from the lower end thereof, said platform, having a chute 23 which communicates with theinterior of a mixing apparatus 24, operated by'a suitable motor 25. The mixing apparatusfz l maybe of any suitable or desired construction, such as'the common type of apparatus usually employed for, mixing concrete. Any

gases .whi ch' may accumulate in the top of the 20 mixer are drawn out by blower l5 and delivered to theburner box 20. A flue 26 connects the receiving chamber with" an offset chamber a of a "lihe"mixer .j2 l discharges into the inlet chute 5 incinerator I' consists of a relatively long cylin- 30 drical chamber lza which is rotatively supported in a lo'ngitudinallyinclined position, by suitable bearings I la. Rotation of said cylinder Illa. may be-also'efiected by means of a gear [211 engaging the gear-ring I3w, encircling the cylinder Illa. A 35 flue '2 60. connects the receiving chamber l4a with offset chamber a. of the stack 3. The incineratorI'; at its lower end, discharges into a burner box 23a, into which is projected one or more burners 2 la, similar to the burners 2i, the deliv- 40 ery ends of the burners being directed axially toward the incinerator'I', in such manner as to project the flame into the open lower end of the latter. The burner casing Zia also rests upon a suitable platform 22a, onto which said chamber 45 I discharges the 'materialwhich has been passed therethrough, said platform also having a chute 23a, which discharges into a second mixer 24a, similar in every respect to the mixer 24, and

driven by a motor 25a, and similarly vented by 50 blower ltd.-

The mixer 240. may discharge into. a suitable storage bin or the like, but it is preferred to discharge'the same into the bottom of a conveyor pit 21, from which a'chain conveyor 28 will detributing chamber 28', adjacent the high end of incinerator I, from which material may be fed to the last-mentioned incinerator through the inlet chute I6. It will be observed that each of the incinerators I and I is provided with an annular bafiie 29, which is spaced a short distance from the delivery end of the chamber.

Located in a suitable position adjacent to the apparatus thus far described is a suitable storage tank 30 for the sewage, preferably in the form of sludge. Leading from the lower end of said tank is a discharge pipe 3|, which delivers the sludge to the pump 32, by which the sludge is delivered to the mixer 24 through a pipe 33. Also leading from the tank 30 is a branch outlet pipe 31a connected to a second pump 32a, which delivers sludge through a pipe 33a to the mixer 24a. The pumps 32 and 320. are driven in suitable manner, as by a motor 34,

In operation, assuming the burners 2| and Zla are lighted and in operation, an initial charge of sand or similar inorganic granular material, capable of withstanding high temperature without fusing, is placed in the pit 21. It is preferred to use good sharp silica sand. Sufiicient sand must be initially employed to insure a continuous stream of sand through all of the incinerators. The sand is elevated to the hopper 28' and introduced into the incinerator I through the chute i5, and the rotation of the cylinder ID will cause the sand to travel slowly downwardly through said cylinder, so that it will receive a high temperature due to the heat generated by the burners 2|. The burners are directed toward the downwardly flowing material in a manner adapted to impart a relatively high temperature to the sand, but the heat must be regulated so as to avoid fusing temperature, because fusing of the sand particles would greatly impair the operation.

The apparatus will be primed for operation at the time that cylinder l0 begins to discharge heated sand from the lower end thereof. As the heated sand is discharged from the incinerator I, it is delivered to the mixer 24. Coincidentally with delivery of hot sand to the mixer,

the pump 32 is put into operation, so as to deliver sludge to the mixer 24 for mixture with the heated sand. The sand and sludge are intimately mixed until the sand particles are thoroughly coated with colloidal portions of the sewage constituents. The coated inorganic material is then discharged into the high end of incinerator I. Because of the rotation of the chamber Illa the coated material will be tumbled about and agitated, and caused to travel downwardly toward the burners Zia, thereby being caused to move through a heated space within which it is subjected to a gradually increasing temperature as it approaches said burners. Therefore, almost immediately after the mixture enters the incinerator I, the temperature is sufficiently high to dehydrate the coatings, and during the subsequent travel of the mixture the temperature is sufficiently increased to ignite the dehydrated organic material, but without fusing the refractory material, and incineration of the organic constituent is completed by the time that the granular carrier material reaches the discharge end of said chamber Ifla and immediately before it is discharged into the mixer 24a. Due to the retarding action of the baffle 29, a constantly moving bed of fire back of the bafile is provided, with the result that complete combustion takes place in this zone, to such an extent that there is 2,175,300 a liver the discharged material to an elevated dispractically no residual matter left by the sewage, and the material discharged to the mixer 24a is practically the dried heated sand. As dehydration and incineration take place during the travel of the mixture, combustible gases are given off, which are ignited by the heat within the cylinder, thereby aiding in the combustion of the dehy drated coatings material. The products of combustion pass to the stack S through flue 26.

As the stream of sand is discharged from chamber Illa, it is delivered to the mixer 24a, and at this time the pump 32a is put into operation, so as to supply sludge to the mixer 24a, as the latter receives the hot sand from said chamber lOa. Said sand and the new sludge are intimately mixed and the sewage-coated refractory material is discharged into the pit 21. From this last position, the mixture of hot sand and sludge is elevated to the platform 28 and discharged into the incinerator I through the chute 5, whereupon, the mixture travels through the chamber In in such manner as to be subjected to the heat of the burners 2|, so that dehydration takes place at the upper portion, and complete combustion takes place at the baffie 29, in the manner already described in connection with the incinerator I, the products of combustion passing to the stack through chamber l6. In both instances the operation is so complete that as dehydration takes place, the combustible gases will also be ignited, thereby materially aiding in the destruction of odors and smoke, as well as in the combustion of the sewage itself, the gases of combustion which are carried to the stack being without noticeable odor. served that once the apparatus has been put into operation, the cycle is continuous and that the same batch of sand may be used over and over indefinitely as long as the heat is kept below the fusing temperature. If desired, however, at the end of a cycle the sand that has been used may be replaced with new sand, the old sand being treated to a separating process of any desirable character, so as to remove any foreign material which may possibly remain, so that the sand is rendered suniciently pure for building purposes. Where a plant of smaller capacity will suifice, a single incinerator I may be employed in lieu of the plurality of incinerators illustrated in Figure 1. Such a modification is illustrated in Figure 3, in which the same type of rotating cylinder lilb is employed, as heretofore described, the same being provided with the receiving chamber Mb, the burner chamber 20b and burners 2lb, rotation of the cylinder being effected in the manner already described in connection with Figure 1. Material from the chamber IOb is discharged into a mixer 2%, which is vented by means of the blower I'Jb, and the mixture discharges through a spout 31 onto a conveyor C, which elevates the mixture to the chute I6b, so as to be delivered into the chamber Mb. Sludge is supplied to the mixer through the pipe 331). The receiving chamber Mb is connected with an extension at of the stack S by means of a flue 261).

In operation of the form disclosed in Figure 3, a charge of sand is first introduced through the chute lfib into chamber I 0b, and is heated by the burners as it travels toward the lower end of said chamber. The hotsand is then discharged into the mixer Web and mixed with sewage sludge in the manner already fully described, and the mixture is deposited upon the conveyor, so that it Will be elevated and discharged into the chute l6b. Thereafter, the mixed sludge and hot sand From the foregoing, it will be obwill travel through the cylinder I 01), and during this travel the sludge will first be dehydrated and then completely incinerated, so that the practically pure heated sand may again be discharged into the conveyor for another cycle. The foregoing cycle may be continued until the supply of sludge is exhausted.

As previously stated, any preferred type of mixer may be employed in the apparatus illustrated in the drawings, but in each instance it is preferred to provide a structure similar to that shown in Figure 3, in which a baflle 35 depends from the top wall of the mixer to a position well below the normal liquid level in the mixture, so as to trap any gases and to allow them to escape into the upper part of the mixer, where they are vented in the manner already described. The mixture is forced outwardly from the mixer through the outlet opening 36 into the discharge spout 31.

The advantages of the invention will be readily apparent to those skilled in the art to which it belongs. An important advantage is that owing to the fact that the sand particles acquire coatings of the colloidal constituents of the water content of the sludge during the passage of the mixture through the incinerator, it is easy to so control its passage that even dehydration and subsequent incineration are effected. Therefore, after the apparatus is once put in operation less heat is required at the burner end than would otherwise be required, thereby preventing fusing of the sand, so that as the sand leaves an incinerator, it may be immediately mixed with more sludge and returned to another incinerator, and a continuous hot sand cycle is provided. Another advantage is that as the sludge is subjected to the heat, it will first give off its moisture and later will be completely incinerated, the combustible gases given off during these stages being capable of developing sufiicient B. t. us. to very materially aid in the destruction of following sewage. Another advantage is that by using two or more incinerators, one set above the other, and the transferring of the hot sand from one incinerator to another, and then back to the first incinerator, a very simple and effective apparatus is provided capable of economic continuous operation. Another advantage is that the mixture of sand and sewage travels in a general longitudinal path, and that the burners project their flames in lines parallel with said path and at the terminal end thereof, so that the hottest zone in each incinerator is adjacent to its annular internal baffle.

Having thus explained the nature of the invention and described an operative manner of constructing and using the same, although without attempting to set forth all of the forms in which it may be made, or all of the forms of its use, what is claimed is:

1. A method of destroying sewage comprising intimately mixing sewage material with heated granular refractory material until the particles of refractory material are provided with coatings of colloidal sewage material, and completely destroying said coatings by subjecting the coated granular material to an incinerating temperature.

2. A method of destroying sewage comprising intimately mixing sewage material with heated granular refractory material until the particles of refractory material are provided with colloidal coatings of said sewage material, and dehydrating and subsequently completely destroying said coatings by subjecting the coated granular material to a gradually increasing temperature.

3. A method of destroying sewage comprising heating an inorganic high temperature-resistant material, intimately mixing sewage material with the heated inorganic material until the particles of said inorganic material are provided with coatings of said sewage material, and effecting complete destruction of said coatings by subjecting the coated material to an incinerating temperature while traveling through a heated space.

4. A method of destroying sewage comprising heating an inorganic high temperature-resistant material by causing it to travel through a heated space, intimately mixing sewage with said temperature-resistant material until the particles of the latter are provided with coatings of said sewage material, and completely destroying said coatings by causing the coated temperature-resistant material to be recycled through the same heating space, and maintaining said space at an incinerating temperature during such recycling.

5. A method of destroying sewage comprising heating a granular refractory material, intimately mixing said heated granular material with sewage material until the particles of granular material are provided with coatings of said sewage material, dehydrating said coatings by causing the coated material to pass through a heated space, and completely incinerating the dehydrated coatings by gradually increasing the temperature of said heated space as the granular material approaches the end of its travel through said space.

6. A method of destroying sewage comprising intimately mixing sewage sludge and a heated high temperature-resistant inorganic material until the particles of said inorganic material are provided with coatings of said sewage, effecting initial dehydration and complete incineration of said coatings by causing the coated material to travel toward a source of heat so as to increase the temperature applied to the coatings during 1 travel of the temperature-resistant material through said heated zone.

'7. A method of destroying sewage comprising intimately mixing heated granular refractory material with sewage material until the particles of the granular material are provided with coatings of said sewage material causing said coated material to travel through a heated zone, to effect dehydration of said coatings, and increasing the temperature of the heated zone as the coated material approaches the end of its travel so as to effect complete incineration of said coatings, and subjecting the coated material to a turbulent tumbling action during its travel through said heated zone.

8. The method of destroying sewage comprising causing heated granular refractory material to travel in succession through a plurality of heating zones, and then recycling the same through said zones, intimately mixing sewage material with said refractory material prior to its entrance into each heating zone during the recycling stage and in such manner as to provide the particles of refractory material with coatings of said sewage material, and effecting complete incineration of said coatings by the action of the incinerating temperature maintained in the respective heating zones during the travel of the coated particles therethrough.

HENRY H. MORETON.

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