Nebojsa Knezevic

Civil Engineering Institute “IG” LLC Banja Luka, Kralja

Petra I Karađorđevića 92-98, 78 000 Banjaluka,

Republic of Srpska, BaH, e-mail: izg@blic.net

RESEARCH OF DISPOSAL TREATMENT OF

HAZARDOUS HYDROCARBON SLUDGE GENERATED

FROM THE REFINING OIL PROCESS AND

REGENERATION OF USED OILS

INTRODUCTION

Contamination of petroleum derivatives is one of the mostserious environmental problems in the world today.

The more numerous reservoirs of oil fuel and other petroleumderivatives that have been buried in the ground are theincreasing danger for the purity of the land and groundwaters.

The tests have shown that in the most cases these reservoirsleak its contents into the environment.

Pollution of the environment with waste oils is a very actualproblem.

In the process of treatment and regeneration of used motoroil there are different tailings and residues, and as such theyrepresent a waste that can not be used for furthertechnological processing.

INTRODUCTION

The sludge is a mixture of oil residues, tar, and sulfuric acidwith admixture of heavy metals and polyhalogenichydrocarbons.

Acid sludge is a black gelatinous mass with following basicstructure: 19-45 % of humidity, 20-35 % of ashes, 40-56 %of carbon, 8 -9,5% of hydrogen, 12-13 % of combustiblesulfure and 12-20 % N+O. The upper calorie power of thiswaste is from 24000 - 28000 kJ/kg, and the lower caloriepower is from 22000 – 25000 kJ/kg. Heavy metals thatappears in this waste are: lead (Pb), cadmium (Cd), nickel(Ni), tin (Sn), zinc (Zn), arsenic (As), copper (Cu), and other.

INTRODUCTION

MATERIAL AND METHODS OF

WORK

In order to obtain relevant indicators of composition of thiswaste and to estimate quantity, it was necessary toconduct extensive research works in site of this landfillthat included: drilling and sampling the sludge and soil,physical and chemical analysis of the same, geophysicsand geodetic researches and recording of the landfill, andall as foundation and starting point for selection ofappropriate procedure for final disposal of this hazardouswaste.

For the selection of the appropriate procedure for thewaste disposal different methods and various solutions offinal waste disposal are analysed, economic analysis of allvariant has been done, and for each variant advantagesand disadvantages have been analysed. Volume ofavailable options of the treatment of this waste is verywide.

MATERIAL AND METHODS OF

WORK

Various solutions of final disposal of the hazardous acid sludge that are

analysed in this paper are:

Recycle of waste;

Neutralization and solidification of waste;

Export and disposal abroad;

Waste deposition;

Use as fuel in power plants and in the process of production of

cement clinker in cement factories;

Pyrolisys of waste;

Processing of waste with plasma technology;

Heat treatment of waste (insineration) and

Thermal desorption.

MATERIAL AND METHODS OF

WORK

Arrangement of measured points of geoelectric soundings and positions for an exploratory well

MATERIAL AND METHODS OF

WORK

For the need of the identification of disposed waste and contaminatedsoil from the vicinity of the sludge landfill was performed sampling onthe landfill of this waste which is placed in the oil rafinery in BosanskiBrod.

These drillings have been done with special geomechanic drilling toolswith accessory equipment which can drill through the waste body. Eightwells have been drilled (five at the landfill and three in the vicinity of thelandfill). Forty samples have been taken for analysis (25 samples ofacid sludge and 15 samples of contaminated soil in the vicinity of thelandfill).

Sampled waste is subjected to thorough laboratory analysis in thelaboratory Chemica s.r.l. Società di Servizi Analisi Chimiche eAmbientali Viale Cadorna, 17- 21052 Busto Arsizio (VA).

RESULTS AND DISCUSSION

Results of the researches on the field showed that theanalysed landfill of the sludge waste is the landfill withhazardous waste under the code 05 01, the waste fromrefining oil process, and now in the mentioned landfillaround 35.000,00 tons of this waste is dumped.

Geologic research works, beside basic purpose to doappropriate sampling of this waste, found certain profilesof the sludge waste in depth and the degree ofcontamination of surrounding soil. Results of theresearches showed that this waste on the analysed landfillis in certain layers, and certain breach has been done indepth and width in the surrounding soil around the landfill.

Sludge waste from sludge pit Količina (m3)

Sludge waste from the vicinity of the sludge pit 34.920

TOTAL SLUDGE 550

Contaminated soil from the vicinity of sludge pit 35.470

Contaminated soil from the slope of the sludge pit 10.590

TOTAL SOIL 3.560

Sludge waste from sludge pit 14.150

TOTAL FOR TREATMENT 49.620

RESULTS AND DISCUSSION

RESULTS AND DISCUSSION

Geologic and later laboratory testing showed that there is around15.000,00 tons of contaminated soil in the vicinity of the landfill thatshould be disposed in an appropriate way.

Results of geophysics researches confirmed this testing and found out in

the measured geoelectric sounds and prognostic 3 D depth model.

Based on the value of specific electric resistance, the following

lithological environments are separated:

• environment 1 - mound, sandy clay, waste;

• environment 2 - hydrocarbon layer (sludge);

• environment 3 - brown clay;

• environment 4 - sandy gray clay;

• environment 5 - sand with water.

RESULTS AND DISCUSSION

RESULTS AND DISCUSSION

RESULTS AND DISCUSSION Quantitative interpretation of geo-electric measuring

points of sounding is based on determination of thespecific electrical resistance and the thickness ofregistered lithological - geoelectric areas.

Interpretation of results of geo-electric sounding isperformed by a computer programs IPI 2win and Res2dinv and graphic - analytic method with help of albumORELIANA - MOONEY for double- and triple- layertheoretic cases. Thereby are determined parameters ρ(specific electric resistance) and h (thickness) for eachrecorded lithological - geolectric area.

RESULTS AND DISCUSSION

Based on determined parameters for ρ and h, it is shown interpreting 3Dterrain model. The following can be concluded from the softwareanalyses results:

Environment with values of apparent specific resistance ρp < 300hmm, corresponding to the lithological complex made by clays.

Environment with values of apparent specific resistance ρp from 300hmm up to 60 0hmm, lithologically corresponding to the clays andsandy clays.

Environment with values of apparent specific resistance ρp from 600hmm up to 120 0hmm, lithologically corresponding to the sand.

Environment with values of apparent specific resistance ρp over 1500hmm, corresponding to the embankments, clayey-graveland sandy layer and landfill waste material.

RESULTS AND DISCUSSION

RESULTS AND DISCUSSION

The following can be concluded according to the analyses of obtained 3Dmodel of sludge landfill:

mound, sandy clay, waste, located in peripheral parts of investigatedlandfill. Thickness of this layer is variable and ranges from 1 m up to 3meters;

hydrocarbon layer (sludge), located in central parts of investigatedlandfill and its thickness ranges from 3 m up to 4 m;

brown clay, located in all parts of investigated landfill. This sectionmakes basis of hydrocarbon layer (sludge layer). Its thickness rangesfrom 1,5 m up to 3 m;

sandy gray clay, represented in all parts of investigated landfill indeeper terrain layers. This section makes basis of hydrocarbon layer(sludge layer). Its thickness ranges from 5 up to 8 meters;

sand with water, extends from gray sandy clay on the 5 meters depthin northwestern to 12 meters in southeastern parts of investigatedlandfill.

RESULTS AND DISCUSSION

Physical and chemical analysis of the sludge waste from the

analysed well (the well G2 which is placed in the centre of the

landfill shows representative well for this landfill), show that

the sludge has:

low pH value (up to 1.7)

large content of humidity (up to 20-40%),

increased content of heavy metals (Cr, Pb, Ni, and other),

which classify this waste as the waste with increased risk

(hazardous waste) to the environment.

Average values of the results of sludge from the well

No Sulfuric parameter Unit

Average

values

1. pH value 4.59

2. Humidity content % 40.86

3. Ash content % 35.13

4.

Concentration of heavy metals

Cu mg/kg 19.252

Cr mg/kg 68.057

Tl mg/kg 0.1

Cd mg/kg 0.1

V mg/kg 10.423

Pb mg/kg 37.732

As mg/kg 1.797

Sb mg/kg 0.1

Sn mg/kg 0.154

Ni mg/kg 38.7376

Zn mg/kg 56.2861

5. PCB concentration mg/kg 0.5910667

6. Cyanide concentration mg/kg 0.014

7. Total content of sulfure, S+SO42- % 13.463633

8. Total content of sulfate, SO42- mg/kg 14249.417

9. Total content of nitrate, NO3- mg/kg 648.22537

10. Total content of nitrite, NO2- mg/kg 0.2687

11. Total content of chlorine mg/kg 16.839033

12. Total content of fluorine mg/kg 24.5218

13. Total content of bromine mg/kg 0.646

14. Calorific value kcal/kg 2719.61

15. Total organic carbon, TOC % S.S 26.145667

16. The total hydrocarbons <12C mg/kg 112.10233

17. >12C % 31.4166

18. Determination of flash point 0C 158.60333

RESULTS AND DISCUSSION On the basis of performed theoretical consideration for final

disposal of hazardous sludge waste, performed waste analyses,waste categorization, economic analyses, the ThermalDesorption Method is selected as the best solution forprocessing of this type of waste.

Analyzing all input waste parameters that should be processedand conditions that have to satisfy plant emissions (air quality,waste water quality and obtained ash and slug quality), and incooperation with thermal desorption plant producer, it is madeflow diagram of hazardous sludge waste thermal desorptionprocess.

All previously performed investigations and analyses, as well asthermal desorption flow diagram should serve as a basis forfuture system designing of hazardous sludge waste treatmentmade in the refining oil process and regeneration of used oils.

CONCLUSION

In the aim of the selection of appropriate technology for the disposal ofthe hazardous sludge waste from the refining oil process andregeneration of used oils, the appropriate research and laboratory workshave been done on the landfill of the hazardous sludge waste and theyincluded: drilling and sampling of the sludge waste and soil, geophysicsand geoelectric researches, geodesy recording of the landfill and physicaland chemical analyses of the waste.

On the basis of the researches and laboratory analysis, clasification andcategorization of the waste have been done in accordance withregulations of waste categories with catalogue. Also, the estimation of thewaste quantity, that is on the landfill, has been done in the aim of the besttechnology selection from the point of technical and economicparameters and conditions of the environment protection.

The waste is categorized as waste from the oil refining process withbasic code 05 01 (muds from the bottom of reservoir, acid base muds,acid tar, other tar, oils that contain acids, spent filter clays, waste thatconclude sulfure from desulfurization of oil).

CONCLUSION

In this sense, in this paper, the possibilities and alternativesolutions of final disposal of industrial hazardous waste areanalysed and the most acceptable technology of the wastedisposal is suggested.

In this paper, all advantages and disadvantages are shownfor each analysed technology (method).

For technology selection important condition was to findtechnologies which could be used “on situ”, on the spot, andwhich could be used relativly quickly.

CONCLUSION

On the basis of all mentioned we can make conclusion that the mostacceptable for the final disposal of the acid sludge waste is thermalmethods of waste treatment, with the following advantages:

• Suggested technology can be relatively easy installed in site, on

landfill of the waste, and large processing capacities of this waste

can be done;

• This technology enables 99,9% of purification of waste emission

gases from waste treatment facilities;

• Waste waters from waste processing are completely purified with

this technology prior to discharge into the ultimate recipient;

• Construction of facilities for thermal desorption is simple, it doesn't

need large infrastructure support and is easy to install;

• Cost of processing hazardous sludge waste with this technology is

the cheapest of all analysed methods in this paper;

CONCLUSION

• There is no any preparation of the waste for application of this

technology, therefore it is complete technology;

• The rest of the thermal desorption process is decontaminated soil

which can be again returned to the site and use it for process of

landfill reclamation;

• Obtained diagram shows that this technology represents a quite

easily technological solution compared to other suggested

technologies, and that for the same, there is no need for a large

infrastructure investment.

• After reviewing the necessary approvals of the competent

authorities for the implementation of this and other methods of

final disposal of the waste and the needed financial investments, it

shows that the use of this technology is the most simple, ecology

the most acceptable and with minimum needed financial means.

Thank You for Your Attention