Original Article

Determination of Soils Properties Texturally Distinguished and their Influence on Thermal Desorption Process

POP Dorina1*, Valer MICLE1, Horaţio FODOR2, Ioana Monica SUR1

1Technical University of Cluj – Napoca, Bd. Muncii No. 103 – 105, 400641 Cluj –Napoca, Romania

2County Office for Pedological and Agrochemical Studies Cluj – Napoca, Str. Fagului No.1, 400483 Cluj Napoca, Romania

Received 10 March 2013; received and revised form 29 March 2013; accepted 7 April 2013

Available online 1 June 2013

Abstract

This paper presents the area soil sampling and the results obtained as a result of determining the physico –

chemical properties. The measurements performed point the fact that the samples have a different texture (P1: sandy - clayey; P2: gouge; P3: clayey). The results obtained will be used in subsequent researches that will follow the highlighting of the influence of soil texture on thermal desorption process of contaminated soils.

Keywords: soil, physical – chemical properties, texture, thermal desorption. 1. Introduction

Soil represents one of the most complex natural systems of the planet, a key – component of the environment, a biological assembly which is in continuous transformation, a system that supports all the basic functions of life on earth [4, 5].

Thermal desorption technology is proposed because it is one of the most effective in terms of eliminating the pollution sources.

Compared to incineration, thermal desorption treats a very wide range of organic contaminants, records a significant fuel economy and produces smaller volumes of residual gases which requires treatment [7].

From various experimental studies [2, 3] emerges that the adsorption phenomena and desorption efficiency are influenced by soil texture and that temperature and time of treatment are key factors in remediation process.

* Corresponding author. Tel.: 0040754617771; Fax: 0040264/415054 e-mail: dddorinaa@yahoo.com; Dorina.POP@im.utcluj.ro

The results of Falciglia P.P researchers, et. all. showed that for the sandy and oozy soils polluted with diesel oil, the necessary remedial temperature is 175°C, while the clay soils require a higher temperature (250 °C) [2].

The purpose of this paper is the determination of soil samples properties to determine the influence of soil texture on the thermal desorption process of some pollutants such as petroleum hydrocarbons. 2. Material and Method

Soil sampling was performed in Cluj county, Bonţida parish, according to STAS 7184/1-75 [9].

Bonţida parish is located near the contact area between Transylvanian Plain and Somes Plateau, mostly on the right bank of Somesul Mic. Geographical coordinate points for locating Bonţida parish are: eastern longitude 23°45’ and northern latitude 46°53' (fig. 1) [8].

Available online at http://journals.usamvcluj.ro/index.php/promediu

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Figure 1. The map of the three points of soil sampling, satellite image [6]

From this parish were performed soil samples

from three different points on the following depth intervals 0 – 20 cm and 20 – 40 cm. The analyses of the main physico – chemical soil properties were performed at the County Office for Pedological and Agrochemical Studies Cluj – Napoca. It was necessary to use the following equipment: pH meter, distiller produced by ITM AMIRO, the complete system Kjeldahl, analytical balance SHIMADZU, spectrocalorimeter METERTECH 830 PLUS, sand bath, adjustable stove for determination the properties. 3. Results and Discussions 3.1. Physical properties of samples

Texture As a result of the analysis on soil

granulometry there were observed the following textures according to the sample and depth (fig. 2):

Sample 1 (P1) – sandy – loamy texture. The taxonomic name of the texture is Calcareous alluvial soil on gravels, sands, clays, sandy - clayey/sandy clayey having ASka-k1d5-u/s-Tft/NB / L-SI-am Q4 the formula.

The appearance of the terrain is normal and the natural conditions in which it occurs are hill – meadow. The fundamental soils they are associated with are aluviosol gleyic şi gley cern.

Morphological characteristics of the soil samples in this section are:

- Ao → 0 – 20 cm: clayey sand; 10YR 4/3 brown color in wet state; structure – small angular polyhedral; well developed; neplastic and non adhesive; coprolite; cervotocine, abundant roots; moderate effervescence; gradual transition.

- A/C → 20 – 40 cm: clayey sand; 10YR 5/4 yellowish brown colour in wet state; structure – medium subradial polyhedra; moderately developed; neplastic and non adhesive; rare roots; strong effervescence; gradual transition.

Sample 2 (P2) – loam – sandy texture. The taxonomic name of the texture is a „Aluviosol eutric on gravels, sands, clays LN/LL”, having ASeu-d6-sql/lql-Tft/NI-* L-SJ- ad p03 Q3 formula.

The territorial unit is spread on river valleys on horizontal surfaces, at about 290.8 hectares and the main soils which are associated with are: „Aluviosol eutric gleizat moderate, Aluviosol epiprundic, Aluviosol gleizat moderate” having the following morphological characteristics:

- Ap → 0 – 20 cm: clayey – sandy; 10YR 5/3 brown colour; small subangular polyhedral structure; well developed; cervotocine; weak plastic and adhesive; common roots, gradual transition.

- Ao → 20 – 40 cm: sandy clayey, 10YR 5/3 brown colour, small subangular polyhedral structure; well-developed; weak plastic and adhesive; roots rare; gradual transition.

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Sample 3 (P3) – loamy texture. Its denomination is „Aluviosol eutric on fluvial deposits clayey/clayey”, expressed by the formula Aseu-d4-lq1/lq2-Spp/CI.

Is spreading is on the meadow, with a natural aspect of the land. The morphological characteristics are:

- Ao → 0 – 20 cm: clayey, 7.5YR 4/3 brown colour; small subangular polyhedral structure, moderate plastic and adhesive; rare roots; gradual transition.

- A/C → 20 – 40 cm: clayey, 10YR 5/4 brown color, medium angular polyhedral structure, moderate plastic and adhesive.

0

10

20

30

40

50

60

70

80

90

0 - 20 20 - 40 0 -20 20 - 40 0 -20 20 - 40

P1 P2 P3

Granulometric analysis according to depth [%]

fine sand

coarse sand

dush I

dush II

argyle

Figure 2. Granulometric analysis chart of soil samples

Apparent density Compared to the optimum apparent density

(1.3 g/cm3) it is found (fig. 3) that in the P1 and P3 points the apparent density is very low and in the

sampling point P2 the value is medium at 0 – 20 cm depth of, probably due to soil compaction by agricultural works and for 20 – 40 cm depth this value is 1.25 so it is very small.

1.17 1.13

1.42

1.25

0.99 1.01

0.4

0.6

0.8

1

1.2

1.4

1.6

The apparent density [g/cm³]

Figure. 3. Apparent density chart of soil sampled

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Hygroscopicity Hygroscopicity coefficient values are

intended for assessing the soil texture based on mutual relationship between them [1]. Thus, the values obtained for the hygroscopicity coefficient

(fig. 4.) shows for P1 point – sandy clayey texture (22/NL) for both depths; P2 – clayey sandy texture (LN) for both depth and in the sampling point P3 a clayey texture (LL/42).

2.411.73

3.76 3.54

5.79 6.2

01234567

0 - 20 20 - 40 0 - 20 20 - 40 0 - 20 20 - 40

P1 P2 P3

Higroscopicity [%]

Higroscopicity [%]

Figure 4. Higroscopicity chart of soil sampled

Total porosity The apparent density influences porosity so

that following analyzes, it can be observed that the

total porosity is extremely high in P1 and P3 points, and in P2 point this is great (fig. 5).

57 5847

5363 63

010203040506070

0 - 20 20 - 40 0 - 20 20 - 40 0 - 20 20 - 40

P1 P2 P3

Total porosity [%]

Total porosity [%]

Figure 5. Chart representing total porosity of soil samples 3.2. Chemical properties

As a result of chemical properties determinations (fig. 6) we can conclude the following: pH results – in P1 sampling point the soil is slightly alkaline; in P2 point at 0 – 20 cm depth the soil is weakly acid and in depth this is neutral. In P3 sampling point the soil is weakly acid in the its entire studied depth with an increase on the depth of 20 – 40 cm which is close to neutral pH.

Soils showing a humus content below 3% are considered poor and those which exceed the value of 8% are rich. The Analyses of soil samples show that they are poor in humus in all 3 sampling points.

In terms of mobile phosphorus quantity we can see that it decreases together with the depth increasing in all three sampling points. Total nitrogen content (fig. 7) shows alow concentration in all three sampling points.

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7.81 8.35 6.86 6.92 6.43 6.892.81

0.69 2.17 1.56 3.18 1.72

33

10

55

40

15

9

0

10

20

30

40

50

60

0 - 20 20 - 40 0 - 20 20 - 40 0 - 20 20 - 40

P1 P2 P3

Chemical properties of soil samples

pH

Humus [%]

P2O5 mobile [ppm]

Figure 6. Chemical properties chart according to depth

0.14

0.034

0.11

0.05

0.154

0.086

00.020.040.060.08

0.10.120.140.160.18

0 - 20 20 - 40 0 - 20 20 - 40 0 - 20 20 - 40

P1 P2 P3

Total nitrogen [%]

Total nitrogen [%]

Figure 7. The total nitrogen content chart of soil samples 4.Conclusions

As a result of determining the physico - chemical properties of the soil samples from Bonţida area/Cluj county, it results that soils from these three sampling points have different textures: P1 – sandy – clayey texture, P2 – claye–sandy texture, P3 – clayey texture.

Analyzed soil porosity is high, fact which

shows that they adsorb water and pollutants, leading to their rapid contamination.

The results of measurements performed will be used in further research which will aim to highlight the influence of soil texture on thermal desorption process of contaminated soils.

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References [1] Berar (Sur) I. M., 2011, Teza de doctorat – Cercetări privind extracţia metalelor grele prin biolixiviere in situ din solurile poluate [2] Falciglia P. P., M. G. Giustra, F. G. A.Vagliasindi, 2011, Low-temperature thermal desorption of diesel polluted soil: Influence of temperature and soil texture on contaminant removal kinetics, Italy, Journal of Hazardous Materials 185, 392 – 400 [3] Prodan C. V., 2012, Teza de doctorat – Cercetări privind aplicarea desorbţiei termice la tratarea solurilor contaminate cu Hexaclorciclohexan, Facultatea de Ingineria Materialelor şi a Mediului [4] Stadnic S., 2010, Pedologie (Ştiinţa solului: geneza, proprietăţile, clasificarea, geografia), Curs de prelegeri, Bălţi

[5] ***, 1978, Metodologia Elaborării Studiilor Pedologice, Partea a-III-a ,,Indicatori Ecopedologici”, Ed. I. P. Oltenia, Craiova [6] ***, 2008, Petrom E&P, Studiu de fezabilitate privind procesarea şlamului existent în depozitele de reziduuri petroliere, Volum I – Piese scrise [7] ***, 2012, Rezumat al raportului la studiul de evaluare a impactului pentru “Înfiinţare reţele de canalizare menajeră în satele Bonţida (parţial) şi Răscruci, comuna Bonţida, judeţul Cluj”, http://mmediu.ro [8] ***, 1998, SR ISO 11464:1998, Calitatea solului. Pretratarea probelor pentru analize fizico – chimice [9] ***, 2013, http://maps.google.com