JPH04180898A - Treatment of mixture of oils and fats and sludge - Google Patents

Abstract

PURPOSE:To economically and effectively treat a mixture of oils and fats and sludge by heating the mixture of oils and fats and sludge in an oil-water separator to separate the same into three layers, and succesively heating crude oils and fats to 101 deg.C or higher in an oils and fats heating apparatus consisting of three or more tanks connected in series. CONSTITUTION:The mixture of oils and fats and sludge stored in a grease trap is recovered by cleaning to be supplied to an oil-water separator 1 and heated to predetermined temp. in the separator 1 to be separated into three layers of crude oils and fats, intermediate water and sludge on the basis of specific gravity difference. The separated crude oils and fats are supplied to a filter tank 3 to remove the solid therein by the screen bucket 4 in the tank 3 and supplied to an oils and fats heating apparatus 2 consisting of several heating tanks connected in series. The crude oils and fats are successively heated to 101 deg.C or higher stepwise in the respective heating tanks and the impurities coagulated by heating are settled on the bottoms of the respective heating tanks by the metal nets 5 provided between the heating tanks. The oils and fats obtained by treating the crude oils and fats in an oils and fats processing apparatus can stable be used as the fuel of a waste oil burner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for treating a mixture of fats, oils, and sludge discharged from factories or workplaces that manufacture, process, or cook food.

[Conventional technology]

From the standpoint of environmental conservation, untreated landfill or ocean disposal of mixtures of oils, fats, and sludge has been prohibited by law, so incineration has generally been performed.

(Standards for disposal based on Law No. 137 of December 25, 1970, Article 12 of the Waste Disposal and Public Cleansing Law, and Article 6 of the Cabinet Order of the same law) [Claim to be solved by the invention] Food-related Oils and fats discharged from factories and workplaces.

Since sludge mixtures generally contain 90-95% water,
Direct incineration requires a large amount of fuel and is expensive, so there was a need to develop an economical treatment method.

In the present invention, after heating and separating a mixture of fats and sludge into three layers of crude oil, intermediate water and sludge, the crude oil is further heated to remove impurities and recovered as fats and oils. Provides an easy and economical method for treating a mixture of oil and sludge by using it as a fuel and saponifying a portion of the oil to make a soap solution, and using this soap solution as a flocculant for the separated sludge. The purpose is to

[Means to solve the problem]

The mixture of oil and sludge is collected in a collector (grease trap) installed in factories, workplaces, etc. to remove oil and fat from wastewater, and is then supplied to the oil-water separator 1. do.

The mixture of fats and oils and sludge heated to 70°C to 80°C in the oil-water separator 1 is separated into three layers of crude oil, intermediate water, and sludge based on the difference in specific gravity.

The separated crude oil capacity is transferred to the screen packet 4 in the filtration tank 3.
After removing solid matter, the oil is supplied to a fat/oil heating bag W2 consisting of several heating tanks connected in series.

The crude oil capacity is heated in stages from 101°C to 110°C in each heating tank, and the impurities solidified by heating are moved to the next heating tank by a wire mesh 5 installed between each heating tank. It settles to the bottom of the respective heating tank without being removed.

Moreover, as a result of this heating, most of the water mixed in the crude oil and fat as an emulsion evaporates as the emulsion breaks, but some of it separates and precipitates.

The temperature of the heating tank needs to be at least 101°C, and it is sufficient if the final heating tank has a temperature of 105°C to 110°C.

The average residence time from the first heating tank to the final heating tank is usually within 1 hour.

The oil and fat obtained by processing the crude oil in the oil and fat heating device 2 can be stably used as fuel for a commonly used waste oil burner.

The oils and fats recovered here are used as fuel for the waste oil boiler, and the generated steam is used for the oil and moisture pre-equipment 1 and the oil and fat heating bag! Used for warming or heating in step 2.

In addition, a part of the recovered fats and oils is saponified with an alkali to form a soap solution, and this soap solution is used for coagulation and concentration of the sludge separated by the oil-water separator 1.

The intermediate water separated in the oil-water separator 1 is supplied to a flocculant mixing tank 11, and FeCQ3 and Ca(OH),
is added and sent to the coagulation sedimentation tank 6, where the pollutants are coagulated and sedimented, and the treated water is discharged to the public sewer system.

The sludge separated and settled in the oil/water front loading w1 is supplied to the sludge flocculating tank 7, where a flocculant is added and the sludge is flocculated and concentrated.
It is dehydrated to form a cake, which can be easily incinerated.

In flocculating this sludge, it is particularly effective to use a soap solution prepared from recovered fats and oils as a flocculant, and it is also preferable to use calcium carbonate or the like.

In the above method for treating a mixture of oil, fat, and sludge, oil and water front loading! ! 1 and the oil/fat heating device 2 can be sufficiently supplied by using the recovered oil/fat as fuel for the boiler.

[Effect]

The crude oil separated in the oil-water separator 1 contains water and other impurities as an emulsion because the mixed organic matter acts as an emulsifier. The oil heating device 2, which often causes clogging and other troubles, is heated sequentially from 101℃ to 1.
By heating to 10°C, the emulsion in the crude oil and fat is destroyed and water is almost completely removed.

The organic substances that act as emulsifiers in the crude oil and fats and other suspended organic substances are dehydrated by heating, coagulate, and settle.

As described above, the water and contaminant organic matter mixed in the crude oil and fat are removed by the oil and fat heating bag W2, and the recovered oil and fat has properties that can be stably used as boiler fuel.

Oil and moisture veneer! The sludge separated in step 1 has a water content of approximately 93% and is mainly composed of organic matter obtained by fermentation of animal and plant residues with organic acids, and is highly hydrophilic. Necessary and essential.

However, the present inventors have discovered that the soap solution prepared from the recovered fats and oils is effective as a flocculant for this sludge.

According to experiments, 10% soap solution was applied to sludge for 1 to 2 hours.
%, and by adding 0.3 to 0.5% of calcium carbonate as an auxiliary agent, the sludge could be effectively flocculated. In this case, the optimal pH condition was 4.5 to 5°.

〔Example〕

A description will be given of the treatment of 1,000 OOQ of waste, which is a mixture of oil, fat, and sludge, discharged during cleaning of a grease trap for kitchen wastewater at a food preparation facility.

The mixture of the above oils and fats and sludge has a pH of 4.0 and a BOD of 8.
%, SS was 4.2%, oil (n-hexane extracted material) was 5.5%, and water was 3.5%.

Separate oil and sludge mixtures! ! ! 1 for several hours, heated to 80°C using a heat exchanger 9, and separated into crude oil, intermediate water, and sludge.

The amount of crude oil and fat separated into the top layer was about 600.

After removing the solids in the crude oil and fat using a screen packet 4, heat treatment was performed using an oil and fat heating device 2 consisting of three types.
The temperatures of the first tank, second tank, and second tank are 101°C, respectively.
The temperatures were 103°C and 105°C.

There was a wire mesh between 30 and 100 meshes between each type to remove heat-solidified impurities.

The sludge consisting of impurities removed with wire mesh and the sludge accumulated in the screen packet is approximately 8Q, and the collected oil and fat is 52Q.
Met.

The intermediate fishing rod 7502 discharged from the oil-water separator 1 was treated by adding ferric chloride and calcium hydroxide in the coagulation sedimentation tank 6, and the supernatant, approximately 700Q, was discharged into the public sewer system.

Approximately 240Q of sludge discharged from the oil-water separator 1 is received in the sludge flocculation tank 7, and 129Q (5%) of a 10% concentration soap solution prepared from the recovered oil and fat and 0.7kg of calcium carbonate (approximately 0.0Q) are added as an auxiliary agent. 3%) was added to coagulate and concentrate the sludge, and the coagulated sludge was dehydrated in a dehydrator 8. About 80k here
g of dehydrated sludge cake was obtained, which could be easily incinerated.

In this example, the amount of oil and fat recovered per time was 5212,
10Q for warming or heating in processing steps.

2Q for soap manufacturing, 10Q for incineration auxiliary fuel
However, the remaining 30 U of fats and oils can be used as other industrial raw materials.

In addition, treated intermediate water and sludge dewatering liquid are BOD.

Both SS and oil have a sewer inflow regulation value of 600■/Q.

600m1g/Q, 30+++g/Q or less.

The total amount of sludge, etc. incinerated was 90,111, including untreated fats and oils.

Compared to the case where the entire sludge mixture is incinerated, it is less than 1710, and the water content of the sludge is less than 80%, making it possible to significantly reduce incineration costs.

The amount of chemicals used in this example was comparable to that used in general water treatment, and did not pose a special burden.

〔effect〕

The present invention deals with oils and fats that have been subject to costly incineration treatment because landfilling or ocean disposal is prohibited.

By recovering fats and oils from a mixture of sludge, it is possible to treat the mixture of fats and sludge economically and effectively, and to use the recovered fats and oils as raw materials for other industries.

As a result, the present invention has the effect of significantly reducing environmental costs in food-related factories and workplaces, and contributing to the effective use of resources.

[Brief explanation of drawings]

FIG. 1 is a process diagram for treating a mixture of oil and fat and sludge. FIG. 2 is a schematic diagram of the main equipment used in the present invention. 1... Oil/water separator 2... Oil/fat heating device 3... Filtration tank 4... Screen packet 5... Wire mesh 6... Coagulation sedimentation tank 7... Sludge coagulation tank 8... Dewatering Machine 9...Heat exchanger 10...Oil storage tank 11...Flocculant mixing tank Patent applicant Shoji Ikemoto, representative of Sanitary Co., Ltd. Procedural amendment (method) Shishomu March 9, 1991

Claims (1)

[Claims] 1. A mixture of fats and oils and sludge is heated in an oil-water separator 1 and separated into three layers: crude oil, intermediate water, and sludge, and then heated to 101°C in an oil-and-fat heating device 2 consisting of three or more tanks connected in series.
By sequentially heating the crude oil and fat to high temperatures as described above, impurities mixed in the crude oil and fat are coagulated and removed by sedimentation,
By removing colloidal water dispersed in fats and oils and recovering them as oils and fats that can be used as fuel, and using a soap solution prepared from the collected fats and oils as a flocculant, the oil and fats are separated from the oil-water separator 1. A method for treating a mixture of oils, fats, and sludge, which is characterized by treating the sludge by coagulating it.