CA1041127A

CA1041127A - Method of rendering waste substances harmless

Info

Publication number: CA1041127A
Application number: CA201,309A
Authority: CA
Inventors: Friedrich Bolsing
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-06-06
Filing date: 1974-05-30
Publication date: 1978-10-24
Also published as: YU147974A; GB1477209A; FR2232517B1; CH606380A5; NL7407581A; IT1013360B; FR2232517A1; YU36680B; ATA466474A; NL175315C; AT335375B; NL175315B; DD112969A5; JPS5032075A; SU913934A3; JPS582000B2

Abstract

A B S T R A C T

A method for treating inorganic and organic waste materials comprises adding an alkaline earth oxide which has been treated with surface active substances to the waste material.
The surface active substance delays the reaction of the earth oxide with water. The mixture of alkaline earth oxide is reacted with an approximate stoichiometric quantity of water to form the alkaline earth hydroxide. The solid produced by this reaction may be disposed in various ways which are not harmful to the environment such as in highway road construction.

Description

The invention relates to a method for rendering waste substances harmless, especially used oils and oily substances.
The increasing use of hydrophobic substances, such as oils and oily substances, as well as macromolecular substances -especially, has created new problems which arise mainly out of the handling of these substances. Particularly the use of old oil, heating oils, lubricating oils and diesel fuels often leads, either intentionally or through negligence, and often due to emergency situations, to dangerous contamination of the environ-ment.
There are a number of methods for rendering harmlessoils or oily substances which, in a single phase or in multiple phase systems, entail an endangerment of the environment. Thus, for example, oil can be chemically reacted by being burned, for example, or biologically degraded.
The combustion method used frequently in combating oil damage results in considerable air pollution if the burning is performed in the open rather than in expensive combustion apparatus. -The use of adsorbents solves the present problem only when the oil can be fixed with them in such a manner that it ischemically unaltered but no longer constitutes any danger to the environment or is accessible to biological degradation. With the ;~
known adsorptive agents such as active charcoal, kieselguhr or bentonite, waste oil, for example, can be adsorptively bound only with difficulty. Large amounts of oil may cement the adsorptive agent, especially in the case of high-viscosity oils, making further processing difficult. It has furthermore been proposed in various ways to treat porous mineral substances with hydro-phobic substances for the purpose of improving their adsorptive characteristics. In this manner hydrophobic waste substances can -- 1 -- '~
~ .
~' .

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1 be preferentially bound, while the water is no longer primarily absorbed. In such adsorptive agents, such as hydrophobized pearlite, however, the absorptive capacity is greatly reduced, since the mineral starting material is partially sealed by sur-face treatment with hydrophobizing substances, so that the inner cavities are no longer accessible.
It is particularly important that the substances which are adsorptively bound by the known processes are so fixed on the adsorptive agent that they no longer constitute any danger to the 10 environmentO
The invention is addressed to the problem of creating a method which in a simple manner will make it possible to render waste substances harmless, especially used oils and oily substances.
The subject of the invention is a method~for rendering waste substance harmless, which is characterized in that an alkaline earth oxide, which has been treated with surface active substances,which delay the reaction with water, is added to the waste substances, the alkaline earth oxide charged with the waste substances is made to react with approximately stoichiometric amounts of water to form the alkaline earth hydroxide, and the solid thus obtained is dumped or a technical application is made of it Whenever the term "waste substances" is used in the '`
framework of the present invention, it is to be understood in its . .
broadest sRnse. Such wastes may be organic or inorganic wastes.
The applicability of the process of the invention is largely independent of the physical state of the waste substances, and is also possible, for example, when the mostly organic wastes are in the form of solids which are still suspended in water at low temperature, and do not become liquid until the temperature is ~ -increased or until they are dissolved by a solvent. They may be

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1 not only one~ase systems and two-phase systems of water and an organic fluid that is not miscible or is miscible only to a limited exten~t with water, but also multiple-phase systems with the inclusion of finely divided solids. The viscosity of the phase containing the wastes is not of decisive importance for the applicability of the method of the invention. -The same applies to the chemical nature of the wastesO
They may be both monomeric compounds and polymers, polycondensates and polyaddition compounds. These substances may be of natural or synthetic origin. Examples of waste substances which occur in practice also in the form of emulsions are: old oils, such as used motor oils, cutting oils, drilling oils, vegetable and animal fats, waxes and wax-like substances such as those produced by the removal of wax from automobiles, tar oils, resins, bitumin-ous substances and pitchesJ acid resins, synthetic resins, petro-leum, petroleum fractions such as gasoline and kerosene, as well .. . .
as machine oils, cylinder oils and lubricating oils, and also aromatic compounds such as benzene and toluene.
The following are given as examples of multiphase systems which are produced, sometimes in large quantities, as a waste product in technical processes, and which can be rendered harmless by the method of the invention:
Acid resinl~, drilling greases, drilling oils, cutting oils, enamel emulsions, waste impregnating emulsions used in the textile industry as well as resin emulsions in the paper industry, synthetic resin emulsions such as are produced in the after-treat~
ment of metals, waste waters containing grease and oil discharged from machines for washing ball bearings and friction bearings, electroplating sludges, bleaching earths charged with oily comp- ~-onents such as are produced, for example, in the decoloring of .~
. . . . -. ~ : . , : : . . . : -1 dark mineral oils, fats and waxesO
Suitable for the performance of the process of the invention are all alkaline earth oxides, ioeO, the oxides of calcium, barium, strontium or magnesium. For the purposes of the -invention, calcium oxide is preferred in the form of the commercial quicklime, e.g., fine white lime, but coarse granules are usable in many casesO The quicklime may contain up to 18 wt-% magnesium oxide or other foreign componentsO As the percentage of magnesium oxide increases the water slaking of the pretreated quicklime charged with the organic substances is slower and takes place with a lesser development of heat, which may be advantageous in a number of applicationsO On account of the preferred use of quicklime the following measures and advantages of the invention will be described only with reference to calcium oxide, although . .
they apply essentially also to t~e other name~ alkaline earth ; ~ -oxides or their mixturesO ~-~
Quicklime reacts with water rapidly and exothermicallyO i: ;
It would therefore be slaked, i.e., transformed to calcium hydrox-ide, in aqueous systems, without needing special preliminary treatment, and the calcium hydroxide would adsorb the oily sub-stances just as unsatisfactorily as directly added slaked limeO
: .:
Even hydrophobized calcium hydroxide has only a comparatively . .
low capacity for the adsorption of oily substances. ~
:, :, Now it has surprisingly been found that calcium oxide behaves quite differently if, after preliminary treatment with hydrophobizing agents, it is reacted in the presence of the waste -~
materials with water which either is already present in the system ~;
in the stoichiometric minimum amount necessary for the formation of hydroxide or is added after the absorption of the liquid wastesO
.

What the reason for this is not entirely understood. Apparently 1 the calcium oxide micelles loaded with the hydrophobizing agent are protected against slaking with water, so that the formation . . ..
of the hydroxide takes place only with a considerable delay whose degree depends on the quantity and chemical nature of the hydro-phobizing agent. ~n-cethe reaction with water of a calcium oxide thus hydrophobized does not take place even after several minutes and may be delayed for as much as an hour or more, we are justified in speaking of a calcium oxide that does not react with water. It is all the more surprising that it can react with water again after it has come in contact with, for example, an organic waste substance, such as oils, and has managed to become charged therewith. It is assumed that the molecules of the hydrophobizing agent first cover the surface of the calcium oxide micelles and protect it against the attack of the water. Under the action of the organic substances contained in the nonaqueous phase, the molecules of the hydrophobizing agent become gradua~ly inactivated -ioe., absorbed by the organic phase, so that water molecules can get to the CaO lattice and, with a considerable increase in vol-ume, form calcium hydroxide whose particles in statu nascendi absorb the organic substances.
In the method o the invention, the surface can increase to more than 20-fold during the formation of hydroxide in the presence of an organic phase. In particular, the surface enlarge-ment depends on the nature of the substance to be adsorbed and on the surface-active substances used, which delay the reaction with water ~nd with which the calcium oxide has been treated. The surface-active substances are contained in the ~uicklime in amounts of from OoOOl to 10% by weight, preferably OoOl to 5 wt-%o They are particularly effective when they are very uniformly distributed - -therein. This can be achieved by intimately grinding the quicklime, ' ~' 1 for example, in the presence of the surface active substancesor by impregnating it with them if they are liquids of low viscosity, or by impregnating it with solutions of the surface active substances. This can be done, for example, by injecting them into a mixing drum in which the calcium oxide is being stirred.
- For the purposes of the invention, surface active sub-stances in the widest sense are suitable. Apparently the only important thing is that they have a special affinity for the ;
waste substance to be separated, especially in the case of an aqueous multi-phase system, so that a preferred interaction with the latter takes place before the reaction with water begins.
Fundamentally, anion-active and cation-active as well as non-ionogenic surface active substances are usab~ë,. Chemically these substances may be in the followi~g classes: fatty acids such as stearic and palmitic acid, alkyl su~fates, alkyl aryl sulfonates, alkyl sulfonates, sulfosuccinic acid esters, salts of carboxylic acids, the true soaps, sulfosuccinamides, ether sulfates,nonylphenylpolyglycol ethers, fatty alcohol polyglycol ethers and their sulfation productsO But polyglycol ethers, ;
aliphatic amines, aminoxides, aliphatic alcohols and c~llulose derivatives as well as polymeric compounds are usable.
The selectivity of the above-named adjuvants for the organic substances to be separated may be adjusted very precisely through the selection of the functional groups and of the chain length of the molecule. This is especially important whenever the substance to be adsorbed is inhomogeneous and contains sub-stances of different origin, e.gO, emulsifiers, lubricant additives, etc.. It is desirable in determining the appropriate adjuvant to start with representatives of a homologous series. If one series fails completely, another is tested. With the aid of simple lab-' '~:' ' 1 oratory tests a suitable representative will be found in known homologous series, such as for example the series of the alkanes, the aliphatic carboxylic acids or the aliphatic alcohols. The precision with which the selective behavior of the adjuvant added to the calcium oxide can be adjusted is surprising to the technical man. For example, an emulsion that could not be separated by any former means can be separated within seconds by using a fine lime pretreated with n-octylamine, but the separation of the emulsion fails when the homologous C12 amine is used.
The adjuvants may also be selected in such a manner as to cancel the effect of certain types of emulsifier present in the multi-phase system that is to be separatedO For example, anion-active emulsifiers, such as soaps for example, can be rendered harmless by cation-active additives, such as long-chain ammonium ;
salts for example, so that the separation of the emulsion takes place substantially rap~dly. The same applies to the addition of other adjuvants, such as hydrocarbons for example.
To render hydrophobic wastes harmless it is desirable to use a calcium oxide treat~d with fatty acids or paraffin oilO
The calcium oxide treated with these or other hydrophobizing ag0nts is not of itself especially hydrophobic, but it loads up--pr2ferent-ially it seems-- with hydrophobic wastes when they occur in aqueous multi-phase systems~ In the course of the gradually beginning reaction of the calcium oxide charged with the organic wastes with the water contained in the aqueous multi-phase system or added in accordance with the stoichiometric requirements, to form calcium hydroxide, the organic substances are adsorbed uniformly and extrem-ely finely. The calcium hydroxide containing the hydrophobic ;
adjuvant and the wastes displays an unusually intensified hydro-phobic behavior, so that it can be separated without difficulty ~ 7 ~ ;~

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1 from any aqueous phase that might possibly remain. Furthermore, the calcium hydroxide that forms remains virtually undissolved even upon long contact with water In view of the properties of the end product of the process of the invention, those hydrophobizing agents are espec- -ially selected which give the calcium hydroxide hydrophibic prop-erties by themselves or in conjunction with the absorbed organic ;
substancesO Suitable for this purpose are, for example, fatty acids, such as stearic and palmitic acid, but also fractions of petrole~m, such as paraffin oil. The selection and amount of the .............. .
hydrophobizing agent will depend decisiv~i*y{~on what is to be done with the end product, i.e., the calcium hydroxide cantaining the waste substances in adsorbed form. As a rule the desired action is achieved by the addition of 0ol to 5 wt-%, especially 1 to 3 wt-%, of the hydrophobizing agent.
In order that the calcium oxide treated with hydro-phobizing agents and in some cases other adjuvants may absorb the wastes before it is reacted to alkaline earth hydroxide -with the w~ter present in the system or added thereto, with the 2~ adsorptive binding o~ the organic substances, it suffices to mix the treated quicklime with the waste substanceO If liquids are involved, it is enough to stir the treated quicklime into them or to imbibe lumps of quicklime with themO If the waste addition- ~' ally contains solidsJ provision can be made for a thorough distrib-ution of the treated calcium oxide in the system by means of suit-~le mixers or kneaders The amount of treated quicklime required in order-to render the wastes harmless depends essentially on the desired state of the end product or the possible use to which it may be puto In the case of liquids it is sufficient to add so much treated calcium ;

1 oxide that the calcium hydroxide containing the wastes adsorptively bound is produced in the form of a dry powder on the basis of its hydrophobic properties. In the majority of practical applications the weight ratio of treated calcium oxide tothe waste substances to be made harmless ranges from about 1:1 to 1:10O
Surprisingly it has been found that the~hydrophobic calcium hydroxide resulting as the end product can be carbonized with the included wastes with exceptional ease, which is evidently due to the fine division of the calcium hydroxide formed in the process of the inventionO After only a few days of storage in air, it is no longer alkaline calcium hydroxide, but calcium carbonate.
Through the appropriate choice of the hydrophobizing agent, this and the adsorbed organic waste substances which are also in finely divided form, can be biologically degraded. In cases in which biological decomposition of the waste is possible, adjuvants which themselves are biodegradable are s~l-ected. These include, for example, natural fatty acids, such as stearic and palmitic acid, and alkanes such as paraffin oil. What has been said also applies when the waste substance still contains a solid phase, and it is, for example, crude oil which is both on and in the soil. In this case it is expedient to use hydrophobized quicklime containing, for example, 0.4 wt-% stearic acid and 0.2 wt-% paraffin Gil in very finely divided formO This can then be blown onto the oil layer according to its thickness; the oil that is on the ground immediately sinks in, and the oil in the soil is brought in contact with the treated quicklime mechanically, with a rotary tiller, for exampleO If the soil~L~mo~sture is insufficient for the reaction, the amount of water necessary for hydroxide formation is sprinkled on and worked in, the distribution of the oil which is in the hydro~
phobized calcium oxide into the large surface area of the end product, - 9 - ~: -' . :. : . . .. . . :

l i.e., the calcium hydroxide, will then take place The charged powdered adsorption agent can be tilled into the subsoil where the oil is accessible to biodegradation on account of its extremely ~ - , . . .
fine division. The calcium hydroxide will be transformed in the course of time into calcium carbonate.
If aqueous multi-phase systems with a highper-centage of acid resins or emulsified used oils are to be made fit for dumping, hydrophobized calcium oxide is added preferably in such amounts that the end product will be a solid.
The dry, highly hydrophobic po~der that results, which is no longer wettable with water, can be used in the form of a layer up to several meters thick as a lining for dumps for oily materials.
That is, this very hydrophobic powder absorbs oil very greedily, so that oil pol~ution can no longer get into the ground water. For example, if calcium hydroxide and used oil are present in an end ~ -product obtained by the present invention, in a weight ratio of 1 ~, additional oil and oily substances can nevertheless be adsorbed in considerable amounts, namely upcto approximately double its ' weightO The hydrophobic end product is particularly well suited 20 for the above-named application if it contains non-biodegradable adjuvants such as, for example, stear~lamine, or dimethylbenzyl-stearyl ammonium chloridec It can also be used to special advantage as a construction material in street and highway construction, esp-ecially as a frostproofing layer.
Lastly, it is very important to transform waste substances such as used lubricating and motor oils, even chemically in some cases. The adsorption in accordance with the instant invention is performed such that the heat of the reaction of the reactive, charged quicklime with water is dammed up until a spontaneous coking process 30 begins. For this purpose the product charged with the waste and ,. .

1 containing the necessary amount of water, but not yet fully reacted to calcium hydroxide, is placed in a ditch and covered with a thin layer of dirt. After a period of time the contents of this "minidump" cokes without any appreciable formation of smoke; this will take place in hours or days depending on the quantity~ What remains is an ash which can be used for ~ertiliz-ing purposesO
The process of the invent'on, however, is usable not only for rendering liquid wastes harmless; sludges can also be rendered harmless, such as those, for example, which are produced by electro-plating processes, or which are produced in the form of charged bleaching earths in the bleaching of dark mineral oils or fatty oils. To this end the alkaline earth oxide to be used in accord-ance with the invention is stirred into the waste sludge in a ratio of about 1:1, and is then further processed in the manner -~
taught by the invention.
Oils floating on water, as well as whole lakes of waste oils representing ~queous multi-phase systems due to the presence of ground water or rainwater, may be rendered harmless by the method of the invention~ It is expedient to select again for this purpose hydrophobized quicklime which has been pretreated with somewhat larger amounts of hydrophobizing adjuvants, namely 1 to 5 wt-%, for the purpose of checking the formation of hydroxide as long and as effectively as possible. The quicklime thus treated is so hydrophobic that it floats on water.
It absorbs the oil at different rates according to the origin of the oil, and sinks when it is charged with oil After a period of time--hours, for example, on open waters~e the chemical reaction with the water begins. This results in the formation of calcium hydroxide which acts as an adsorptive `' 7 . ~
1 agent which in statu nascendi fixes the oil in very finely divided formO If the adjuvants serving for the pretreatment of the ~uicklime are appropriately selected, this end product is biodegraded after a period of time.
In combatting oil on deep waters, suitable oxygen carriers can be added to the treated calcium oxide, which promote ~ -not only chemical but also biological degradation. These include, for example, nitrates and sulfates. They are locked onto the particles after the reaction and cannot be eluted by the water on account of the hydrophob~c shell.

For the elimination of 190 kg of used motor oil, 190 kg of quicklime containing lwt-% stearic acid and 0.2 wt-% sodium diisooctylsulfosuccinate is mixed in with ito Then the calcium oxide is reacted with 80 1 of waterO After about 30 minutes a ~ ' powdery, dry solid is obtained, one kilogram of which can still absorb approximately one half kilogram of additional used oil.

100 kg of an electroplating sludge containing approx-imately 20 wt-% of inorganic and organic components plus 80%
water can no longer be broken down to separate a clean aqueou~
phase on account of its consistency. 150 kg of pretreated quick-lime (1% fatty acid) is stirred into it. The water that is present is completely eliminated by the formation of hydroxide and by evaporation due to the heat of reactionO A highly hydrophobic powder forms which contains the components of the electroplating sludge 90 fixed that the dumped product is no longer wetted by surface or ground waterO

500 kg of a pasty emulsion containing 240 kg of various ~(~4~1Z ~
1 organic substances is mixed by stirring with 500 kg of a fine white lime pretreated with 5 wt-% of a mixture of stearic and palmitic acid. After the reaction a dry3 dumpable powder is formed.

10 kg of an acid resin industrial byproduct is placed in a kneader in which sulfuric acid present in the resin is first neutralized with untreated quicklime. Then 4 kg of water and 10 kg of fine white lime are added, the latter having been treated with 2 wt-% of a mixture of stearic and palmitic acid and 0O5 wt-% of succinateO During the kneading only the resin is at first absorbed -by the hydrophobized calcium oxide. The reaction with water does not take place until after about 20 minutes of additional mechanical treatmentO A dumpable powder results 100 kg of diesel oil is to be removed from a sea beach.
Aperoximately 100 kg of fine white lime plus 1 wt-% of a mixture of stearic and palmitic acid and 0.5 wt-% paraffin oil is distrib-uted over the beach by means of a spreader truck with a proportion-ing apparatusO Then the ground is worked over with a rotary tiller to such a depth that all of the diesel oil that has seeped into the soil comes in contact with the pretreated fine white lime.
After 80 liters of water have been sprayed on the ground i5 tilled again~ The end product that ~orms can be left in the ground since it contains the diesel oil in very finely divided form, ioeO, in easily decomposable form.
EX~MPLE 6 . .
One cubic meter of an emulsion from a special dump is ~ ~ -treated in a tank equipped with a propeller type agitator with 600 g of a pretreated calcium oxide containing 5% of a nonylphenyl polyglycol ether. Then the propeller agitator is operated for l about l minute. The emulsion precipitates and in about 10 seconds a botb~m sludge has formed, the supernatant liquid consisting of clear water. The purified aqueous phase is decanted -and theremainder plus the sludge is filtered on a belt filterO
After the chemical reaction of the sludge the hydrophobic components ~ -from the oily phase of the emulsion are so fixed on the adsorptive agent that the end product can be dumped as a dry powderO

One cubic meter of a synthetic resin dispersion contain- ;
ing ap~ oximately 7% synthetic resin is stirred energetically with l kg of pretreated calcium oxide (2~ paraffin oil) for several ;~
minutæ~SO The synthetic resin immediately precipitates and sinks ~-on the adsorptive agent to the bottomO Filtration with a belt filter yeilds a clarified aqueous phase and, after the chemical reaction of the sludge, a dry powderO ~;

Two kg of an adsorptive agent consisting of ~uicklime with 2 wt-% paraffin oil is stirred into 100 liters of an aqueous neutral emulsion containing 2 kg of drilling oil. After a fewS-minutes complete clarification tak0s place; the bottom sludge isremoved by filtration. The pH of the aqueous m0dium is at first 11, but by brief gassing with air it is easily reduced.

! An aqueous emulsion from a machine shop (2 kg oil in 100 1 of water) is stirred with 2 kg of quicklime containing 6 wt-%
nonylphenoltetraglycol etherO Within 2 minutes complete clar-ification of the emulsion takes placeO The solid end product is removed by filtration For the separation of a synthetic resin dispersion con-:' . -1 taining 400 g of an epoxy resin per liter, the adsorber ~electedis a mixture or calcium oxide and magnesium oxide (10% MgO) con-taining 1 wt-% paraffin oil and 1 wt-% nonylphenol tetraglycol ether, 50 g of this adsorber is stirred into 1 liter of th~ ; -synthetic resin dispersion. After 5 minutes clarification of the ~; ~
dispersion takes placeO The precipitated solid is removed by ~-filtration.

' Approximately 50 tons of crude oil which is lying on arable land and some of which had seeped into the soil are rendered harmless in the following manner: approximately 50 tons of pow-dered calcium oxide containing 0O5 wt-% of a mixture of stearic acid and palmitic acid plus 0.2 wt-% of paraffin oil very finely distributed therein are deposited with a blower from a hopper truck onto the surface of the crude oil (approximately 15 cm thick).
After about 30 minutes the free oil is absorbed by the treated calcium oxide. This results in a thin slurry of treated oxide and oil. Then the soil is worked with a rotary tiller to such a depth that all of the percolated oil comes in contact with the calcium oxide. In spite of the presence of moisture in the soil, no reaction with the ground water takes place until all of the oil has~been adsorbed in the mechanical working by the calcium oxideO
In the chemical reaction a dry and hydrophobic powder is formed of the oil slurry in the soil. The end product, which was part-ially on the surface of the ground and partially in the soil, is buried with a bulldozer at a depth of about 50 cm under the previously bulldozed subsoil, where tne oil, no longer recogniz-able as a phase is accessible to biological decomposition after the carbonization of the calcium hydroxide, due to its being ~ ;~

so very finely divided.

t^X`r~MPlE 12 1 From a pond whose surface is covered with an oil slick about 10 cm thick, oil and water are pumped into a conical con~
tainer with a capacity of about 5 m e~uipped with a stirrer. -At the bottom of the cone with the container has an outlet valve In addition, a second outlet valve is installed on the con~ iner such that, after the liquid above it has been drained, a volume of 600 liters of liquid will remain. After the water-oil mixture is pumped in ~e oil floats on the surface of the water in the tankO Excess -water is let out of the tank through the side valve and the pumping action is repeated until approxim tely 1600 liters *
of oil have collected in the tank (measured by a level mark Underneath the oil the re~uired amount o~ 600 liters of water will thus be present. By means of a screw conveyor 1600 liters of powdered, pretreated (with 1 wt-% of a fatty acid mixture of C
to C18 acid) calcium oxide are added, and the stirrer is started up. The calcium oxide at first rapidly mixes with the oil and is ~-not wetted by the waterO Not until after 10 minutes of stirring is the water also absorbed by the suspensionO A thin slurry formsO
This slurry is immediately released through the bottom valve into a reaction vessel i~ the resultant product is to be further pro-cessedJ or, if the end product is to be dumped, it is immediately delivered to the floor of the dumpO Here the chemical reaction takes place after a period of time (about 1/2 to one hour) and a dry, hydrophobic powder forms in whichthe oily phase is no longer recognizable.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method for rendering harmless an oily waste material comprising mixing an alkaline earth metal oxide with a surface active agent which has a special affinity for the waste sub-stance to be separated and which temporarily delays reaction between the alkaline earth metal oxide and water until after the alkaline earth metal oxide has interacted with the oily waste material, combining the alkaline earth metal oxide carry-ing the surface active agent with said oily material, and reacting the alkaline earth metal oxide charged with the waste material with water to convert the alkaline earth metal oxide to the hydroxide.

2. The method of claim 1, wherein the oily waste material is insoluble in water and is present in an aqueous multiple-phase system.

3. The method of claim 1, wherein the alkaline earth metal oxide is calcium oxide.

4. The method of claim 1, wherein the alkaline earth metal oxide is also treated with about 0.1 to 5% its weight of a hydro-phobizing agent prior to mixing with the oily waste material, whereby the alkaline earth metal oxide is rendered hydrophobic.

5. The method of claim 4, wherein the alkaline earth metal oxide is calcium oxide and the surface active agent is used in about 0.01 to 5% and the hydrophobizing agent in about 1 to 3%

by weight of the calcium oxide.

6. The method of claim 1, wherein the surface active agent is biologically degradable.

7. The method of claim 2, wherein the pretreated alkaline earth metal oxide is added to the aqueous multiple phase system in such quantity that a solid forms as the end product.

8. The method of claim 1, including the further step of exposing the alkaline earth metal hydroxide containing the waste material to the action of carbon dioxide.

9. The method of claim 1, wherein the alkaline earth metal oxide charged with oily waste material is reacted with water under a protective cover so that the heat of reaction effects coking of the waste material.

10. The method of claim 1, including the further steps of lining a dump site with the alkaline earth metal hydroxide laden with the oily waste material and thereafter piling dump waste on said lining.

11. The method of claim 1, including the further step of laying down the alkaline earth metal hydroxide laden with the oily waste material on a road bed.

12. The method of claim 3, wherein the calcium oxide is mixed with about 0.01 to 5% its weight of a surface active agent selected from the group consisting of a fatty acid, paraffin oil and an aliphatic alcohol, the calcium oxide carrying the surface active agent is combined with at least an equal weight of the oily waste material, and the calcium oxide charged with the oily waste material is reacted with approximately the stoichiometric amount of water.

13. A method of claim 1 wherein the amount of said surface active agent is from 0.001 to 10% by weight of said alkaline earth metal oxide.