RESEARCH ON THE INFLUENCE OF METALLURGICAL INDUSTRY WASTE ON SOIL AND GROUNDWATER QUALITY Daniela Cîrțînă 1, Eugen Traistă 2

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1 Journal of Chemical Technology Daniela Cîrțînă, and Metallurgy, Eugen Traistă 49, 3, 2014, RESEARCH ON THE INFLUENCE OF METALLURGICAL INDUSTRY WASTE ON SOIL AND GROUNDWATER QUALITY Daniela Cîrțînă 1, Eugen Traistă 2 1 Constantin Brancusi University of Tg. Jiu, Romania, cirtinadaniela@yahoo.com 2 University of Petrosani, Romania, eugen_traista@yahoo.com Received 28 May 2013 Accepted 07 April 2014 ABSTRACT Metallurgical industry waste lead to soil pollution both by removing from the circuit some land areas, the degradation of the physical and chemical quality of soils, the diffuse emission of noxious compounds and by the contamination of groundwater, on areas far beyond the perimeters of storage. The influence of metallurgical waste on soil and groundwater quality is determined especially by the chemical composition of metallurgical slag as by the interactions with the environmental factors mentioned. The paper presents aspects of the chemical composition of some types of metallurgical slag generated from the metallurgical industry of Romania and the influence exerted by the metallurgical slag deposits on soil and groundwater quality. Keywords: waste, metallurgical industry, soil, groundwater. INTRODUCTION Industrial processes produce large amounts of waste that, due to lack of facilities and poor exploitation are among the recognized as generating impact and risk to the environment and public health. The main forms of risk and impact caused by deposits of metallurgical waste, in the order that they are perceived by the population, are: changes of scenery and visual discomfort, air pollution, pollution of surface and groundwater, changes in the composition of soil fertility and neighboring land biocoenoses. Even in the event of future rehabilitation of the areas affected, be it near, removal of land consisting of metallurgical slag heaps out of natural or economic circuit is a process that can be considered temporary, but in terms of sustainability it spans at least two generations when adding construction time (1-3 years), mining (15-30 years), ecological restoration and postmonitoring (15-20 years) [1]. An environmental problem in areas developing metallurgical industry are hazardous materials (including toxic sludge, slurries, metallurgical slag) which are stored, usually in common with municipal solid waste. This situation could generate inflammable, explosive or corrosive mixtures and combinations; on the other hand, the presence of easily degradable waste can facilitate decomposition of complex hazardous components and reduce environmental pollution. A negative aspect is that many useful recyclable materials are stored together with non-recyclable ones, being mixed and contaminated chemically and biologically, and their recovery is difficult [3]. Waste management strategy takes into account the following basic principles: the principle of prevention at source; the polluter pays principle, which states that waste management costs are borne by the waste generators; the precautionary principle, so that 311

2 Journal of Chemical Technology and Metallurgy, 49, 3, 2014 the measures and actions taken are to anticipate environmental impacts; the proximity principle, according to which the waste will be managed close to the source of generation. In 2003, metallurgical industry generated about 5,3 million tons of waste, accounting for over 17 % of the total amount of waste from economic activity. Out of these 3,1 million tons and 58 %, respectively, l were recovered. Currently, the slag heaps of ferrous metallurgy industry occupy an area of over 300 hectares and contain over 100 million tons of waste particularly slags. In this context metallurgical waste management, especially dross, play an important role because waste is not only a potential source of pollution, but they can be a source of secondary raw materials. Therefore, efforts are being made for the purposes of encouraging increased use of slag in areas where use skills were demonstrated, meaning a more efficient exploitation of natural resources [4]. EXPERIMENTAL To assess the quality of slag from metallurgical industry there were made determinations of the chemical composition of slag samples of black and red color Table 1. Chemical composition of black slag. Component Value, % MgO 0,1929 Al 2 O 3 24,5876 SiO 2 26,3903 P 2 O 5 0,0676 K 2 O 0,9133 CaO 12,7987 TiO 2 4,6932 V 2 O 5 0,3466 Cr 2 O 3 4,2687 MnO 0,4085 Fe 2 O 3 19,7413 NiO 0,0581 CuO 0,0425 Ga 2 O 3 0,0332 As 2 O 3 0,0048 Rb 2 O 0,0196 SrO 0,0908 ZrO 2 1,4840 collected from the ArcelorMittal landfill of Hunedoara county, Romania. Components determined in the composition of these materials are shown in Table 1 and Table 2. Test results of levigated materials (levigation test 1/10) for metallurgical slag collected fom the ArcelorMittal landfill of Hunedoara county are presented in Table 3. Ferrous metallurgical slag processing brings benefits in terms of environmental protection, in terms of community or agriculture and from a technical standpoint: ferrous metallurgical slag, being non-toxic materials, but with physical and mechanical properties similar to rocks, are a viable alternative in some applications even more valuable than natural alternatives in the building field. RESULTS AND DISCUSSION The negative influence caused by industrial landfills in ferrous metallurgy industry can be quantified upon the environmental factors soil and groundwater. Sealing of natural or economic land for landfills spans during the Table 2. Chemical composition of red slag. Component Value, % MgO 0,3438 Al 2 O 3 24,8235 SiO 2 16,4172 P 2 O 5 0,1643 SO 3 0,0458 Cl 0,0066 K 2 O 0,3203 CaO 18,3148 TiO 2 6,2607 V 2 O 5 0,2888 MnO 0,3302 Fe 2 O 3 26,3512 NiO 0,1212 CuO 0,0302 As 2 O 3 0,1744 Rb 2 O 0,1444 SrO 0,1132 ZrO 2 0,5561 Nb 2 O 5 0,0210 CdO 0,

3 Daniela Cîrțînă, Eugen Traistă Table 3. Results of metallurgical slag levigated material analysis. Parameter UM black slag Value red slag ph Unit ph 7,64 7,64 As mg/kg s.u. 0,07 0,08 Ba mg/kg s.u. 1,59 2,08 Cd mg/kg s.u. 0,00 0,00 Cr total mg/kg s.u. 0,14 0,13 Cu mg/kg s.u. 0,68 0,49 Hg mg/kg s.u. 0,00 0,00 Mo mg/kg s.u. 0,01 0,01 Ni mg/kg s.u. 0,14 0,11 Pb mg/kg s.u. 0,01 0,01 Sb mg/kg s.u. 0,00 0,00 Se mg/kg s.u. 0,00 0,00 Zn mg/kg s.u. 0,08 0,09 Chloride mg/kg s.u Fluoride mg/kg s.u. 0,03 0,03 Sulphates mg/kg s.u Phenol mg/kg s.u. index 0,00 0,00 DOC mg/kg s.u. 0 0 TDS mg/kg s.u planning, operation, ecological rehabilitation and postmonitoring, which implies a significant impact on all environmental factors. Forms of impacts due to existing landfills are summarized in the following aspects: some existing landfills are located in the vicinity of riparian areas and/or near surface water resources, not fitted properly to protect the environment, leading to pollution of soil and groundwater in the area [2]. Leakage slopes landfills located near surface waters contribute to their pollution with organic substances and suspensions. Abandoned landfills with non-waterproof waste from metallurgical industry are often the source of groundwater pollution by nitrates and nitrites, as well as other pollutants. Both landfill seepage and water running down the sides influence the quality of soils, which in turn affect their utilization. Moreover, the negative effects of metallurgical slag mountains, especially in height in the city unincorporated areas, exercise due to their weight, high pressure on underground water crossing the dumps, practically bottlenecking water supply in neighboring localities [5]. However, the most important impact is determined by the organization of industrial waste landfills which leads to removal from the circuit of areas of land and implicitly quality deterioration of their soils. Solid residues occupy large areas of land for installation of dumps resulting in the accumulation of a sordid mass, landscape degradation, groundwater pollution, preventing the use of soil. Heaps of ashes and slags of ferrous metals industries contain traces of toxic heavy metals (Cu, Zn, Cd, Pb), SO 2 and As. Powders and dust cover the neighboring mining region and suppress vegetation with Aeolian deposits. Liquid wastes pollute soil by polluted water infiltration that partially purify by depositing harmful elements in the soil. Infiltrated wastewater produces significant changes on the surface and in the immediate vicinity of the surface (chemical content, ph, soil fertility) so adversely changing the development environment of flora and fauna. Scale oil deposits affect soil surface they spread on and the groundwater they infiltrate into. Residues have 313

4 Journal of Chemical Technology and Metallurgy, 49, 3, 2014 long persistence and degrade the soil for long periods. Decantation ponds occupy large areas, minerals and toxic residues deposited in them reaching the ground is hard and very little degradable by microorganisms and soil is immediately and irreversibly degraded by dissolution. The quality of the soil also influences on the formation and protection of water sources, both surface waters, and especially the underground. A special feature is the self-purification of soil. This is achieved by the presence in soil of a large number of microorganisms which contribute to the degradation of waste and destruction of pathogens. Other factors that contribute to self-purification are: low temperature, low humidity in the surface layers of soil, lack of support for food, the presence of soil s own germs (forming flora called the telluric flora) [6]. Graphs of soil quality in the metallurgical slag heaps, depending on the ph, is shown in Fig. 1 and Fig. 2. To reduce the impact of waste on the environment there it is necessary for legislation to encourage reduction of waste at source and their capitalization. It is also necessary that the specific regulations ensure the necessary framework for safe management of waste regarding the environment and human health, and solving certain problems in economic activity, in terms of high profitability compared to other resources. The modality of valorization slag from ferrous metallurgy at Member State level is highlighted by the following statistics: 4,7% reused in the manufacturing plant; 23,1% for external use; 10,8% sold elsewhere and 61,4% in deposits. Of course, the main goal in valorizing steelworks slag is the recovery of metal mechanically driven in slag and of metal scrap resulted from various sectors of metallurgical plants that are mixed with slag heaps. The solution adopted for the extraction of ferrous slag is the electromagnetic one. Deferrization steel plants are designed to recover metal from slag and in many cases to granulometrically prepare the deferrizated slag for use in various sectors of the economy. Extensive research conducted in recent years on the steelworks slags have demonstrated the possibility of their use in various fields such as steel industry, construction, railway construction, hydrotechnical constructions, road construction, civil engineering, agriculture, cement industry, glass industry, refractory material industry etc. Procedures applied worldwide for powdery waste 314 Fig. 1. Soil quality in the metallurgical slag heaps. Fig. 2. Soil quality in the decommissioned area. recovery are pyro-metallurgical, hydrometallurgical and other processes, such as: hydrocycloning, pelletizing, briquetting hot and others [7]. CONCLUSIONS Romanian metallurgy has currently technological gaps regarding the collection, transport, storage and especially the exploitation of all categories of waste. Worldwide, about 80 % from the waste steel is recovered, while in Romania, currently it is recovered maximum 48 % of them, the rest being heaped. Dumping this waste in heaps leads to both environmental pollution by removing land areas out of circuit and hence soil quality deterioration, diffuse recesses of noxious compounds and contamination of groundwater, on surfaces far beyond the perimeters of stockpiles. Worldwide there is developed an intense activity to find solutions for the full recovery of steelworks slag. Their use is driven by both economic and environmental considerations, environmental protection, aiming at the abolition of slag heaps. By harnessing slag deposits currently totaling approx. 200 million tons and continuously increasing, we

5 Daniela Cîrțînă, Eugen Traistă will be able to recover large areas of land that can be restored to agricultural circuit (after a prior improvement) or used as industrial areas. Extensive research conducted on steelworks slags during recent years has demonstrated the possibility of their use in various fields such as: steel industry, construction and agriculture. In line with its commitments under the Accession Treaty, Romania must comply with the policy and requirements of the environmental community acquis in the field of industrial waste management. Therefore it requires large-scale exploitation of waste slag from the steel industry and their use instead of natural resources in order to reduce environmental impact and to respect the principle of sustainable development. REFERENCES 1. T. Apostol, A. Badea, C. Mărculescu, Environmental management system, Politechnica Press Publish, Bucharest, M. N. Bălănescu, I. Melinte, A. Nicolae, Environmental risk assessment, Printech Publish, Bucharest, Gh. Bularda, D. Bularda, Waste street and industrial, Technical Publish, Bucharest, O. V. Bold, G. A. Mărăcineanu, Municipal and industrial solid waste management, MatrixRom Publish, Bucharest, A. Reiss, Pollution and environmental protection, Sitech Publishing House, Craiova, S. Vişan, S. Creţu, C. Alpopi, The Environment Pollution and Protection, Economic Publishing House, Bucharest, A. Wehry, M. Orlescu, Recycling and disposal of organic waste, Orizonturi Universitare Publish, Timișoara,