Waste Water Cleaning from Oil Products Based on Non organic Coagulants and Oil Oxidizing Bacteria

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1 Waste Water Cleaning from Oil Products Based on Non organic Coagulants and Oil Oxidizing Bacteria Aleksander Sh. Gershenkop 1, Galina A. Evdokimova 2, Natalia P. Mozgova 2 1 Mining Institute, 2 Institute of Industrial Ecology of the North of the Kola Science Center RAS, Russia galina@inep.ksc.ru Received 25 February 2014; Accepted 11 March 2014; Published May Science and Engineering Publishing Company Abstract The combined cleaning method of waste water out of transport service and petroleum bases has been developed based on non organic coagulants and oil oxidizing bacteria (OOB). Introduction of native bacteria of g. Pseudomonas have increased the intensity of floccules formation. The best results were achieved when using aluminium containing coagulant and introducing bacteria before coagulant introduction. Suggested method provided for maximum permissible concentrations (MPC) of oil products for fishery waters. Keywords Waste Water; Oil Products; Cleaning; Bacteria; Coagulants; Flotation Introduction Along with long time use of microorganisms for food production, food additives, drugs, etc., it is widely used in beneficiation and processing of minerals. Many countries utilize microorganisms and their metabolites long since during metal leaching from low grade sulphide ores thus providing for full recovery of natural raw materials. Basic studies of the last decade show that some bacteria can play a positive role in the processes of low grade ore beneficiation by flotation and flocculation. Bacterial cells and their metabolites can be used as flotation reagents and contribute to selective mineral processing. Today these studies are carried out mainly using sulphide minerals, however, the pre exist for such studies using oxide minerals, in particular, those found in iron ore. In a comprehensive review of the research related to mineral processing of R. Dwyer1 et al., 2012 the issue is discussed of possible use of bacteria and its metabolites as flotation reagents during beneficiation of iron ores of Australia. It is shown that hydrophobic bacteria of Micobacteria phlei and Rhodococcus opacus can be used as flocculants in the beneficiation of hematite being non sulphide mineral [R. W. Smith, et al., 1993; R. W. Smith, et al., 2006; L. M. S. Mesquita, et al., 2003]. The studies are carried out on importance of bacteria of circulated waters in flotation of apatite nepheline ores [G. A. Evdokimova, et al., 2012]. The idea is to use oil oxidizing bacteria as an embryo of flocculation in the waste water cleaning from oil products (OP). Formation of oil effluents is characteristic of the majority of industrial enterprises, petroleum bases, transport services etc. Many of them are equipped with treatment facilities or have devices for waste water purification from oil products, its efficiency will not allow to obtain permissible concentrations before discharging it into natural water reservoirs. Lack of efficient and cost effective technologies for waste water treatment, tight standards of maximum permissible concentrations of oil products content in discharge, inadequate control on the part of water protection and environmental agencies result in the fact that it is easy to pay fines rather than invest funds into construction or reconstruction of treatment facilities. For each department of manufacturing company often have various contaminant admixtures content, the solution can be given using progressive technologies of water recycling or discharging water into natural water reservoirs with required purification efficiency. 57

2 Advances in Water Resource and Protection (AWRP) Volume 2, 2014 The practice shows that the easiest and most available method is coagulation of admixtures found in waste water by providing intense floccules formation and its further reduction from purifying water. This waste water treatment method is characterized by maximum increase of sorption capacities of floccules with contamination admixtures including in its composition, increasing the speed of its sedimentation, decreasing of coagulation threshold. As it was shown in previous studies, joint application of different coagulants, surfactants, ph optimization of environment contributes to a great extent to waste water treatment process efficiently [Ye.D. Babenkov, 1977]. Floccules formation significantly reduces the necessary surface areas of sedimentation ponds [A.Sh. Gershenkop, et al., 1995]. In order to intensify the floccules formation the surfactants were introduced, they were the basis for flotation to withdraw the floccules [A.Sh. Gershenkop, et al., 1995; A.Sh. Gershenkop, et al., 2000]. In purified waste water, the oil product content in water for household needs doesn t exceed 0.3 mg/l [Hygienic requirements to surface water protection, 1980], for fishery waters 0.05 mg/l [List of fisheries regulation standards, 1999]. This data was set requirements to purifying water. In the course of study, we take into account standard values of ph of purifying water. The study aimed at obtaining MPC of oil product content in discharged waste water of transport services and petroleum bases required for fishery waters. Objects and Methods of Study Oil products are a dispersed part of this study; they can be referred to colloid component due to its small concentration. These particles are characterized by natural hydrophobic properties, being easy to be included in micelle composition, have minor frothforming capacity. Model were carried out with artificial contamination by OP of tap water and waste water directly with transport services and petroleum bases. Experiments on coagulation of waste water contamination containing 5 mg/l of OP were performed with non organic coagulants. Oil product content in water for experiment was of the same content as in the waste water after rough cleaning. The non organic coagulants were iron sulphates in concentrations of 50, 75, 100 mg/l and aluminium sulphates 80, 100, 120 mg/l calculated using anhydrous salts. Taking into account the fact that lack of coagulant concentration can result in astabilization of colloid particles, in case of excess it is a new stabilization (restabilization) of particles due to its recharge and changes of ph values of environment. In such there was no floccules flotation because it was only coagulation efficiency that was established. In specific cases anion surfactants of 20 mg/l concentration were used to intensify floccules formation [A.Sh. Gershenkop, et al., 2000]. Residual concentrations of surfactants can overestimate oil product content in purifying water as oil product content refers to amount of non polar and low polar compounds extracted by carbon tetrachloride, hexane and petroleum ether. This allows obtaining total hydrocarbon content in spite of its origin. In some, fine dispersed activated carbon was introduced to increase sorption surface of floccules and CaO as an additional coagulant for providing additive effect of both coagulants. In of waste water purification, two strains of OOB of Pseudomonas were used and extracted from clarification pond of Belomorsk petroleum basis of Murmansk region. Suspension of two strains of bacteria of n x 10 7 cell/ml was introduced into water containing 5 mg/l of OP, then after mixing (during 1 minute),iron sulphate or aluminium sulphate were introduced. To make a comparative evaluation, coagulant and bacteria introduction procedure was varied from purifying water. Experiments were carried out without introducing bacteria too. was determined by plating on meat and peptone agar just after its introduction into purifying water and after experiment in the liquid phase and sedimentation, i.e. in floccules sedimented on the bottom. OP content [Methods of mass fraction measurements, 1998] was evaluated using luminescent fluid analyzer Fluorat 02 of Lumex company production. Results and Discussions Table 1 contains data of hydrocarbon content in decantate in experiment with tap water after adding iron sulphate (coagulant), sodium oleate (surfactant) and OOB suspension of different density. As showed, introduction of bacteria 58

3 insignificantly increases the content of organic carbon in purifying water. TABLE 1. HYDROCARBON CONTENT (MG/L) IN DECANTATE IN EXPERIMENT WITH SURFACTANTS. FeSO4 condition Oleate Na OOB (cell/ml) ph Hydrocarbon content During, we condidered issues related to sequence of bacteria and coagulants introduction. First, we took control over OOB distribution between sediment and clarified water after one day of settling with introduction of bacteria after all reagents. Hydrolysis of coagulants was achieved at ph equal to 8 (Table 2). TABLE 2. BACTERIA DISTRIBUTION BETWEEN LIQUID PHASE AND SEDIMENT AFTER 24 HRS OF SETTLING WITH INTRODUCTION OF BACTERIA AFTER ALL REAGENTS initia solution solution after 24 sediment hrs FeSO activated carbon activated carbon activated carbon Note. Unit amount of all reagents is mg/l here and in tables 3 and 4. As it follows from the data of the Table, significant number of bacteria is kept in solution after one day s settling in all variants of experience. Other series of included bacteria suspension added prior coagulants and other reagents introduction into working solutions. In this case, floccules formation took place in presence of bacteria thus providing increasing its sorption capacity and transfered bacteria and floccules into sediment. We followed surfactants effect on bacteria population in solution and in sediment as well as during first experiment. Surfactants introduction has intensified floccules formation and gave possibility to make flotation to withdraw formed floccules out of system. This indicated the practical excluding of use of sedimentation ponds or significant reduction (10 times less) of their areas. This data can be found in the Table 3. TABLE 3. BACTERIA DISTRIBUTION BETWEEN LIQUID PHASE AND SEDIMENT AFTER 24 HRS OF SETTLING WITH INTRODUCTION OF BACTERIA BEFORE ALL REAGENTS initial solution sediment solution after 24 hrs < < < In further it was observed the influence of various concentrations of coagulants on bacteria distribution between solution and sediment (Table 4). Coagulant hydrolysis was carried out at рн = 8. TABLE 4. BACTERIA DISTRIBUTION AFTER 24 HRS OF SETTLING AT DIFFERENT CONCENTRATIONS OF COAGULANTS AND BACTERIA IN MOTHER SOLUTION WITH BACTERIA INTRODUCTION BEFORE REAGENTS initial solution solution after 24 hrs sediment 1 Al2(SO4) Al2(SO4) FeSO FeSO It was found out that coagulant concentration increase had low impact on bacteria distribution between solution and sediment. Number of OOB used for water treatment from oil products was evaluated by waste water contamination level but it should be no less than n cells per 1 ml. Model with artificially contaminated water provided to work directly with waste waters of transport services and petroleum bases. On this purpose aboriginal oil oxidizing bacteria were introduced into purifying waste water after rough 59

4 Advances in Water Resource and Protection (AWRP) Volume 2, 2014 TABLE 5. OIL PRODUCT CONTENT IN THE WASTE WATER DURING ITS PURIFICATION BY OIL OXIDIZING BACTERIA AND NON ORGANIC COAGULANTS Oil product Al2(SO4)3 content in FeSO4 consumption water in purified consumption in sediment purified water Note. A dash indicates that the reagent has not been entered. cleaning. They started interacting with colloid particles of oil and OP. Then coagulant was added to form floccules containing OP and bacteria. Immobilization of bacteria by floccules took place directly in purifying water. Oil and oil products being a part of floccules contributed to bacteria accumulation by floccules. Floccules obtained this way and have increased its sorption capacity in relation to OP. and obtained results are presented in the Table 5. According to described above methods, the initial concentration of OP in purifying water was 5 mg/l after rough cleaning. In, 3 and 6 bacteria were introduced after coagulant feed. in 2 and 5 prior coagulant introduction. Experiments 1 and 4 were carried out without bacteria introduction. Presented data showed that immobilization of OOB by floccules formed during hydrolysis of non organic coagulants (at рн=8) contributes to waste water purification from OP till MPC for fisheries. In variants without bacteria with coagulants. OP content in purified water exceeded maximum permissible concentrations. Use of aluminium containing coagulant was more preferable to iron sulphate due to residual concentrations of iron in purified water of more than 0.3 mg/l. At the same time, the content of Al2O3 in purified water was insignificant. it was about 0.01 mg/l when using aluminium containing coagulant. It is important to consider the order of input components for water treatment. Best results are achieved with the introduction of bacteria prior coagulant addition. This contributed to immobilization of bacteria by floccules and increase of its sorption activity. i.e. bacteria introduction increased intensity of floccules formation. Obtained floccules could be separated using settling or flotation. The sedimentation pond area required was evaluated by settling rate of floccules. When using flotation for floccules removal. OP content could be estimated excluding residual concentrations of surfactants determined in concurrent blank tests. Therefore, introduction of aboriginal oil oxidizing bacteria of g. Pseudomonas and non organic coagulants into purifying water containing oil products provided for achieving MPC by oil products for fishery waters. The best results were obtained when using aluminium containing coagulant and bacteria introduction prior coagulant introduction. REFERENCES A.Sh. Gershenkop, V.F. Skorokhodov, L.P. Sulimenko, L.L. Kreimer, Intensification of waste water published BI 5, 1998, purification processes. Gorny informatsionnoanalitichesky bulleten, MSMU, No. 3, 2000, pp G.A. Evdokimova, A.Sh. Gershenkop and N.V. Fokina, The impact of bacteria of circulating water on apatitenepheline ore flotation, Journal of Environmental Science and Health. Part A: Toxic/Hazardous Substances and Environmental Engineering, Vol. 47, 2012, pp Hygienic requirements to superficial water protection. SanPin L. M. S. Mesquita, F. F. Lins and M. L. Torem, Interaction of a hydrophobic bacterium strain in a hematite quartz flotation system, Int. Journal Miner. Process,Vol. 71, (1 4), 2003, pp List of fisheries regulation standards: maximum permissible concentrations and estimated safe level of hazardous substances impact on water and water entities of commercial fishing importance, Moscow: VNIRO, Methods of mass fraction measurements of oil products in soil samples using liquid analyzer Fluorat 2, Quantitative chemical analysis of soils, Moscow,

5 Patent of RF С16 С02 F 1/52. «Waste water purification method». A.Sh. Gershenkop, L.A. Man kuta, Yu.V. Il chenko, Priority dated R. Dwyer, W. J. Bruckard, S. Rea and R. J. Holmes, Bioflotation and bioflocculation review: microorganisms relevant for mineral beneficiation, Mineral Processing and Extractive metallurgy (Trans. Inst. Min. Metall. C), Vol. 121, No. 2, 2012, pp R. W. Smith, M. Miettinen, Microorganisms in flotation and flocculation: future technology or laboratory curiosity? Miner. Eng., 19, (6 8), 2006, pp R. W. Smith, M. Misra and S. Z. Chen, Adsorption of a hydrophobic bacterium onto hematite implications in the froth flotation of the mineral, Journal Ind. Microbiol. Vol. 11, No. 2, 1993, pp Ye.D. Babenkov, Water treatment by coagulants, Moscow: Nauka,

1 Introduction Overview of iron ore reserves and production

1 Introduction Overview of iron ore reserves and production 1 Introduction 1.1. Overview of iron ore reserves and production Iron, the chemical element present in most of the naturally formed ores, has been used since the Neolithic period as raw material for the