Ilkka Välimäki

Suitability of the Respirometric Bod Oxitop Method for Determining the Biodegradability of Oils in Ground Water using Forestry Hydraulic Oils as Model Compounds

Different forestry hydraulic oils were used as model compounds for evaluating the applicability of the respirometric BOD Oxitop method in following the progress of biodegradation of oils in ground water. It is obvious that the biodegradability values of substances depend on the measurement medium used. In this study the same ground water was used in all the ground water experiments. It was observed that the biodegradability of hydraulic oils is dependent on the oil type, being faster for bio oils than for mineral oils. The rate of biodegradation of used hydraulic oils was slower than that of corresponding new oils. All the experiments show that the respirometric BOD Oxitop method is a good and reasonable method for monitoring the biodegradability of oils in water, and the method is independent of the biology and composition of the measurement medium. No changes to the equipment are necessary if conditions are changed. Because the method needs only one sample for measurement, and monitoring of the pressure in the closed bottles is automatic, biodegradability is determined easily and quickly. The precision of the results studied was good. By contrast, traditional measurement of biodegradability using IR, for example, is time consuming, requiring several samples and a considerable amount of poisonous extraction solvent (CCl4). Nevertheless, studies describing the biodegradability of oils using the respirometric BOD Oxitop method have not been published previously.

Leachability of metals in fly ash from a pulp and paper mill complex and environmental risk characterisation for eco-efficient utilization of the fly ash as a fertilizer

Abstract A five-stage, sequential leaching procedure was used to determine the distribution of metals (Cd, Cu, Pb, Cr, Zn, Ni, Co, As, V, Ba, Ti and K) in fly ash from a pulp and paper mill complex between the water-soluble fraction (H2O), exchangeable fraction (CH3COOH), easily reduced fraction (HONH3Cl), oxidizable fraction (H2O2.CH3COONH4), and the residual fraction (HF+HNO3+HCl). The possible environmental risk associated with the eco-efficient utilization of fly ash as a fertilizer, especially the Cd load, was estimated. In addition, the mobility (i.e. bioavailability) of Cd, Cu, Pb, Zn, Ni and Cr was evaluated. The fly ash was derived from an electrostatic precipitator of a fluidized bed boiler in the co-combustion (55% bark and wood residues,45% peat) process at pulp and paper mill in Northern Finland. The accuracy of the leaching procedure was tested using a certified reference material SRM 1633b (Coal Fly Ash). The metals were determined by graphite furnace atomic absorption spectrometry (GFAAS) or by inductively coupled plasma atomic emission spectrometry (ICP-AES). The mobility factors (i.e. bioavailability) of the metals followed the order: Cd, Cu, Zn, Ni, Pb and Cr. The fly ash from the pulp and paper mill was enriched in Ca, Mg, P and K, and could therefore be used as a soil amendment for liming purposes.

Wear Metal Analysis of Oils

This article concentrates on reviewing the literature related with wear metal analysis of oils. An overview on the existence of metals in oils and typical wearing situations is discussed briefly. Different pre-treatment methods of oil samples before wear metal analysis are presented with application remarks. Common measurement techniques of wear metal analysis, both qualitative and quantitative, are handled and compared with each other.

Studies of biodegradability of certain oils in forest soil as determined by the respirometric BOD OxiTop method

The suitability of the respirometric BOD OxiTop method for biodegradation studies of different oils in soil was assessed. Different forestry chain oils and wood-preservative oils were used as model substances. Experiments were carried out on different types of Finnish forest soils. The results of these experiments are in good agreement with our earlier results of oil-biodegradation experiments in water. The BOD OxiTop method proved to be a highly suitable analysis method for biodegradation studies of oils in soil.

Determination of Heavy Metals in Waste Lubricating Oils by Inductively Coupled Plasma–Optical Emission Spectrometry

Abstract In accordance with EU strategy on waste, the utilization of waste oils as a fuel in local power plants has become an interesting choice in hazardous waste treatment planning. The present requirement in Finland is that all oil batches to be burned in power plants must be analyzed for six heavy metals. Thus rapid and cheap methods are needed for these analyses. We have studied and optimized the analytical conditions in the use of sequential inductively coupled plasma–optical emission spectroscopy (ICP-OES) for the quantitative determinations of heavy metals (Cd, Cr, Cu, Ni, Pb, V) in waste lubricating oils. The study showed that using that proposed kerosene dilution method, waste oils can easily be analyzed for heavy metals and the analytical performance of the method is good. In addition, the results suggest that, at least in the case of the Oulu Municipal Waste Management the use of a pair of indictor metals should be sufficient for required determination of heavy metals.

The Use of a Five-stage Sequential Leaching Procedure for Risk Assessment of Heavy Metals in Waste Rock Utilized in Railway Ballast

A five-stage sequential leaching procedure was used to determine the distribution of 10 metals in three combination samples taken from waste rock material, originating from a Finnish zinc mine, and used as railway ballast in Northern Finland. The leaching procedure consists of the following five sequential fractions: a water-soluble fraction (H2O), an exchangeable fraction (CH3COOH), an easily reduced fraction (NH2OH-HCl), an oxidizable fraction (H2O2 + CH3COONH4), and a residual fraction (HF + HNO3 + HCl). The results show, in accordance with all earlier corresponding studies, that a sequential extraction procedure is very suitable for evaluating the effects of external conditions on the solubility of harmful heavy metals, and that external conditions have a large effect on their leachability/solubility, and therefore on their mobility, bioavailability, and environmental risk. In addition, the total concentration of each element is much larger than its solubility in each of the first four fractions (1)–(4) – the potential bioavailability fractions – because the highest concentrations of all metals occurred in the residual fraction (5). The conditions of this phase – three strong acids and strong, long-lasting shaking – are never possible in nature, and therefore the residual fraction is called the inert phase. Thus, the total concentrations of the heavy metals are poor measures of real environmental risk and give no information about the effect of external conditions on their solubility. In addition, the dependency of different elements on the external conditions differs.

Correction of spectral interference of calcium in sulfur determination by inductively coupled plasma optical emission spectrometry using multiple linear regression

Interference effects caused by calcium when determining sulfur from extracted soil samples by inductively coupled plasma optical emission spectrometry (ICP-OES) were studied. The multiple linear regression (MLR) model was utilized for this purpose. Interferences were classified according to how they affected the regression coefficients in the MLR model. Although MLR methodology has been widely used in different instrumental techniques, this was a new viewpoint in ICP-OES methodology. It was observed that calcium caused a severe spectral overlap at the sulfur emission line. Calcium had been reported to cause matrix effects in earlier studies, but these were not observed in this study. The MLR model was also utilized as a calibration function to correct the observed spectral interference. The developed method proved to be accurate and easy to use when compared to two separate single variable regression models previously used to correct spectral interference. The number of standards required for calibration was reduced from 12 to 6. Thus, the time required for calibration or re-calibration was decreased substantially.

Comparison of Different Standard Methods to Evaluate the Total Concentrations of Heavy Metals in Waste Rock

The mining industry is a very rapidly increasing production sector in Finland. Many new mines have been opened recently and others are in the planning phase. Mining legislation has been recently revised and compilation of an ID-directive (Industrial Emission Directive, 2010) required to implement environmental law revision is in progress. The aim of this study was to compare different digestion methods recommended by the Finnish Environmental Administration for threshold and guideline value determinations in the Finnish PIMA Decree (214/2007) and Government Decree (591/2006) concerning recovery of certain wastes in earth construction. Altogether six methods were tested, of which five were microwave-assisted acid digestion methods: ISO 11466, EPA Method 3051A (aqua region), EPA Method 3051A (HNO3), EPA Method 3051A (HNO3/HCl), and SFS-EN 13656, while one was a fusion method with lithium tetraborate (ASTM C 1391 - 95). The results showed that concentrations of heavy metals (As, Cd, Co, Cu, Ni, Pb, Sb, V, and Zn) can be determined reproducibly with standard methods, but the chemical method used can have a significant impact on the results. This conclusion is very important, because the measured heavy metal values can affect the classification and processing of waste materials, and thereby can significantly impact the cost of treatment.

Release of metals from grate-fired boiler cyclone ash at different pH values

Abstract The concentrations of metals (Ba, Cr, Zn, Cd, Ni, Cu, As, Hg, Pb, Mo, Se and Sb) extractable from cyclone ash, obtained from a municipal district heating plant (6MW) incinerating forestry and sawmill residues, was studied as a function of pH (1.1-12.8) at a liquid-to-solid (L/S) ratio of 10L/kg. The following main fractions were obtained: (1) metals (Ba, Cr, Zn, Cd, Ni, Cu, As, Hg, Pb and Sb) that were primarily extractable in extreme or strongly acidic conditions; (2) metals (Cr and Zn) that expressed amphoteric behaviour, i.e. they were extractable both in acidic (low pH) and alkaline (high pH) conditions, but were relatively insoluble at neutral pH values; and (3) metals (Mo and Se) which were primarily extractable only in alkaline conditions. The maximum extraction recovery (R) value (%) of the metals, which varied between 1.3 and 93.4%, indicates that most of the metals in cyclone ash are not easily soluble in the conditions normally found in nature.

Evaluation and Optimization of the Oxidation efficiency of a UV-Persulphate-Oxidation Toc-Analyzer for the Determination of Oil Contamination from Forestry in Ground Water

Different chain oils (tall, rape seed and mineral oils) have been used as model compounds to evaluate and optimize the applicability of UV-persulphate TOC-analyzer for quantitative determination of forestry oils and to follow the progress of their biodegradability. It was shown, that K 2 S 2 O 8 -UV-oxidation method is not sufficient to oxidize chain oils completely. There were differences in oxidation efficiency between different oils, changing from about 46% measured for tall oil to about 25% observed for rape seed chain oil. The addition of Triton X-100 surfactant up to 2% (w/w) was observed to increase the oxidation efficiency, e.g. to 75% for tall oil. The observations can be explained by assuming that in the presence of surfactant the emulsions are more homogeneous and stable. Optimization using two-level full factorial design (temperature of the oxidation chamber and the amount of persulphate) was studied. The results show that the UV-persulphate-oxidation TOC-analyzer is not suitable method to monitor biodegradability of chain oils.