HU203708B - Process for treating and agricultural utilizing oil-containing slam of waste waters - Google Patents

Abstract

A fertiliser is produced by mixing the dehydrated oil waste residue with a nitrogen binding bacteria, such as Rhizobium, Azobacter or Clostridium and with gibberiline and/or substance with a large specific surface, e.g. bentonite, montmorillonite, zeolite, alginite or perlite.

Description

The present invention relates to a process for the treatment and agricultural utilization of oil-containing sewage sludge.

It is known that as motorization increases, more and more oil-containing sludge is produced, which, if released to the soil without proper treatment, can cause serious environmental pollution. Therefore, it is generally the case that the oil-containing sludge is either dewatered or placed on a desiccant bed or centrifuged, then mixed with sawdust and placed on agricultural land. This process is labor intensive, costly and utilization of agriculture is not significant.

Alternatively, such sludge is incinerated, but at a high investment cost.

It is also known that the oil content of sewage sludge can be decomposed by oil-decomposing bacteria [e.g., U.S. Patent No. 2,234,637 to Taggert,

1941) and its refinements, e.g., U.S. Patent No. 2,413,278 (Zobell, 1946), U.S. Patent No. 2,442,476 (Taggert, 1948)]. Examples of bacteria that can be used for direct oil decomposition include: B.aliphaticum, decomposed to C6C34 (isolated by Tausz, 1919), B.aliphaticum liquefaciens, decomposed by cyclic compounds (isolated by Johnson)

1942), B.benzol, decompose benzene, xylene (isolated by Norris, 1944), B.hidium, decompose kerosene (isolated by Tausz, 1919), BJipolyticum, decompose paraffin (isolated by Söhngen, 1913), B.stutzeri, decontaminate (isolated) Söhngen, 1913).

However, the direct production of such bacteria is difficult (not only the production of pure but dominant cultures is difficult), and the degradation of the oil content of large quantities of sludge is difficult to achieve in practice (Davis, J.B. Bull.AmAssoc.PetroIeum Geol., 1952); Porter, J.R .: Bacteriol Chemistry and Physiology, Wiley, New York (1976); Amer.Petr.Inst. Petr. Facts and Figur. 9th Edition, New York, (1950); Hoppe-Seyler, Bér., J. Petroleum, Technol., Oil and Gas, J. Soil Science], The major disadvantage of the use of oil-eating bacteria is that they break down only certain compounds and, moreover, have an adverse effect on health by attacking the skin.

It is also known that nitrogen-binding bacteria can be used to decompose oil, which completely decomposes the oil. For example, British Patent No. 1,177,077 discloses a fertilizer containing a solid or liquid hydrocarbon and a living microorganism, such as a nitrogen-binding bacterium, and, if desired, additives such as bentonite.

The disadvantage of all known processes is that the oil is degraded slowly and / or at an inadequate rate.

The present invention is based on the discovery that by decomposing the oil content of sewage sludge with nitrogen-binding bacteria of the genus Rhizobium, Azotobacter or Clostridium, the efficiency of the decomposition can be increased by the simultaneous use of gibberellin and optionally a high specific surface area. This solution is based on our discovery that the faster and better the breakdown, the more oil can be converted into an oil-in-water emulsion using nitro2 gene binding bacteria. Among the emulsifiers we use for this purpose, gibberellin is particularly potent because it contains cycloparaffin rings which are oleophilic and the carboxyl and hydroxyl groups attached to the rings are hydrophilic. Thus, this compound not only exerts a biological synergism, but also a diaffin, and indeed a triaff in, because it binds to water, oil and soil, thereby significantly reducing the time of oil breakdown and increasing its efficiency.

Other emulsifiers that may be used are those with a high specific surface area which have a thixotropic property and also improve the emulsion degradation by providing a favorable alkaline pH for the fungi.

According to the present invention, the oil-containing sewage sludge, optionally dewatered, is treated with nitrogen-binding bacteria of the genus Rhizobium, Azotobacter or Clostridium, gibberellin and optionally a high specific surface area, and the treated sludge is then applied to the soil surface. soil.

Nitrogen-binding bacteria are preferably aerobic species of various Rhizobium and Azotobacter species, in particular commercially available Rhizobium or Philazonid (manufactured by Phylaxia). The following are some examples of preferred nitrogen-binding bacterial species:

Azotobacter chrococcum (Beijerinok), Azobacter indius (Beijerinok), Azobacter agilis (Beijerinok), Azotobacter vinelandi, Azotobacter beijerinokia, Rhizobium leguminosarum (Frank), Rhizobium phascoli (Dangearum), Rhizobium trifolii (Dangeariz), (Kirchner), Rhizobium melüoti (Dangeard).

Clostridia such as Clostridium pasteurianum can be advantageously used under anaerobic conditions. In a preferred embodiment, gibberellin is obtained using Giberella fungus (Fusarium moniliforme), a fungus metabolic product that is soil-friendly, thereby synergizing, stimulating a nitrogen-binding bacterium such as Clostridium pasteurianum.

The advantage of using high specific surface materials, besides promoting emulsion formation and alkalizing the pH, is to prevent leaching in high permeability soils and to bind any toxic heavy metals that may be present. Bentonite (including sodium or ammonium bentonite), montmorillonite, zeolite, alginite or perlite is preferably used as a high surface area material.

In carrying out the process according to the invention, the treated sewage sludge spread on the soil surface is routinely sprayed into the soil, to which a butterfly plant such as alfalfa is then sown. However, it is also possible to treat the treated sludge 30-31 below the soil surface

HU 203 708 Β om deep.

The advantage of the process according to the invention is that its implementation does not require any additional investment and is easy to implement. On sandy soils it results in nutrient enrichment, thus increasing yields, increases water retention capacity, on hard soil it positively influences soil cultivation, makes the soil crumbly and thus has a positive effect on crop yield.

In summary, the process of the present invention provides for faster and more efficient oil degradation than known hitherto without the presence of harmful carcinogenic derivatives.

The process of the invention is illustrated by the following embodiments

Example 1

To the wastewater sludge containing 2000 mg of oil (expressed as solvent extract) per liter are added 10 liters of commercial solution of Rhizobium, 0.25 cm gibberellin, 10 g sucrose, 1 g potassium hydrogen phosphate and 1 g citric acid per liter. The thus treated sludge is uniformly covered and plowed on sandy soils with a low humus content, and after a year alfalfa has been added to the soil at an oil content of 100 mg / l as determined from the soil sample.

Example 2 To a dewatered sludge with an oil content of g / kg (expressed in solvent extract) is added 40 liters of m3 of Rhizobium solution per m 3. /liter.

Example 3

In the same manner as in Example 1, 15 kg of bentonite per m3 are added to the sludge and the treated sludge is spread over a soil with a permeability of 2.10-5 cm / s after a year, with an oil content of 90 mg / l.

Example 4

Clostridium pasteurianum and g / liberellin are added to 2,000 mg per liter of sewage sludge. The sludge thus treated is spread on sandy soil and applied to the soil at a depth of 40 cm.

After a year, the oil content of the soil is 80 mg / liter.

Claims (2)

1. A process for the start-up and agricultural use of oil-containing sewage sludge using nitrogen-binding bacteria of the genus Rhizobium, Azotobacter or Clostridium followed by spreading the treated sewage sludge on the soil, gibberellin and optionally a high specific surface area 2. A process according to claim 1, wherein the high specificity diyl material is bentonite