Landfarming of Polycyclic Aromatic Hydrocarbons and Mineral Oil Contaminated Sediments

Chapter .. Introduction Landfarming of polycyclic aromatic hydrocarbons and mineral oil contaminated sediments 1 Landfarming of polycyclic aromatic hydrocarbons and mineral oil contaminated sediments Promotor: Prof. Dr. Ir. W.H. Rulkens Hoogleraar Milieutechnologie Wageningen Universiteit Copromotoren: Prof. Dr. H.J.P. Eijsackers Hoogleraar Natuurbeheer in relatie tot algemene milieukwaliteit Vrije Universiteit Amsterdam Prof. Dr. R.C. Sims Hoogleraar Biological & Irrigation Engineering Utah State University Promotiecommissie: Prof. Dr. Barbara Maliszewska-Kordybach Institute of Soil Science and Plant Cultivation, Poland Prof. Dr. R.N.J. Comans Wageningen Universiteit Prof. Dr. P.C. de Ruiter Universiteit Utrecht Dr. A.M. Breure RIVM, Bilthoven 2 Chapter .. Introduction Landfarming of polycyclic aromatic hydrocarbons and mineral oil contaminated sediments Joop Harmsen Proefschrift ter verkrijging van de graad van doctor op gezag van de rector magnificus van Wageningen Universiteit, Prof. Dr. Ir. L. Speelman, in het openbaar te verdedigen op maandag 22 november 2004 des namiddags te vier uur in de Aula 3 Landfarming of polycyclic aromatic hydrocarbons and mineral oil contaminated sediments CIP-gegevens Koninklijke Bibliotheek, Den Haag Author: Harmsen, J. Title: Landfarming of polycyclic aromatic hydrocarbons and mineral oil contaminated sediments PhD-Thesis, Wageningen University, Wageningen, the Netherlands, 344 pp. - With ref. - With summary in Dutch ISBN 90-8504-112-0 4 Abstract Abstract Harmsen, J. Landfarming of polycyclic aromatic hydrocarbons and mineral oil contaminated sediments Doctoral thesis, Wageningen University, Wageningen, the Netherlands, 344 pages. Key words: landfarming, sediment, polycyclic aromatic hydrocarbons, mineral oil, biodegradation, bioavailability, risks, target value, intensive, passive. Due to the necessity of continuous dredging activities in the Netherlands, there is an enormous amount of contaminated sediments generated. These sediments require an efficient treatment procedure to reduce contaminant levels at low costs and with reasonable spatial demands. Landfarming offers a good solution for sediments contaminated with Polycyclic Aromatic Hydrocarbons (PAHs) and mineral oil. Sediments become aerobic during landfarming, which enables aerobic organisms to biodegrade the contaminants. Two main principles and types of landfarming are distinguished: (1) Intensive landfarming, in which processes are optimised using active management activities to reduce contaminants to residual concentrations as quickly as possible and (2) Passive landfarming, consisting of minimal management activities that are used when rapid bioremediation is not necessary, but residual concentrations of contaminants must be reduced. PAHs and mineral oil are strongly ad- or absorbed by the organic matter in the sediment. Biodegradation of these contaminants in landfarmed sediment is shown to be a slow process and often high levels of residual concentrations are left. It is therefore important to understand limiting conditions for biodegradation. Limiting conditions that are discussed and mathematical described include (1) desorption and diffusion of the contaminant within soil aggregates to a place with active micro- organisms, (2) presence of active micro-organisms, and (3) aeration of the dredged sediment. The concept of bioavailability and its use to predict biodegradation and the risks during landfarming are also extensively discussed. Landfarming of dredged sediment has been applied from 1990 onwards on the landfarm Kreekraksluizen in the Netherlands. From these long-term experiments it was possible to recognise fast, slow and very slowly degradable fractions of PAHs. The degradation rate constants of these fractions are derived from the measured data. To fully degrade these three fractions requires, respectively, 1 year, about 7 years, and 30-60 years. Optimisation of the degradation process (dewatering, temperature, aeration and activation of biological activity) only leads to an acceleration of the 5 Landfarming of polycyclic aromatic hydrocarbons and mineral oil contaminated sediments biodegradation of the fast degradable fraction. Therefore, optimisation of passive landfarming is not effective in most cases. Risks for the retention (ability to adsorb contaminants and to prevent mobilisation) and habitat (optimal functioning of soil living organisms) functions of the landfarmed sediments on Kreekraksluizen have been studied by measuring leaching, application of several bio-assays, and monitoring biological activity in general. Risks for the retention function decreased very rapidly during dewatering. The risk for the habitat function decreased more slowly. Small effects in bio-assays were still measurable after 7 years of treatment. No measurable risks were present in the longest (12 years) treated sediments. As a traditional management practice, slightly polluted sediments from ditches in the rural area of The Netherlands are spread over adjacent land. In experiments on the island of Goeree-Overflakkee, it has been shown that the practise of spreading of thin layers also led to fast, slow and very slow degradation of the PAHs present. The historical practise of spreading had led to a small but stabilised increase, of the PAHs- concentration beside the ditches. This thesis concludes with a description of the application of passive landfarming in real-world situations, as it is combined with nature development, used in construction, and combined with growing of biomass for energy production. The presence and effects of heavy metals are also discussed. 6 Abstract Contents Abstract 5 Preface 6 1 General introduction 6 1.1 Introduction 6 1.2 Development of landfarming 6 1.2.1 From waste treatment to soil treatment 6 1.2.2 Landfarming of sediments 6 1.2.3 Impact of target values 6 1.3 Developments in research 6 1.4 Application of landfarming 6 1.4.1 Biodegradable contaminants 6 1.4.2 Heavy metals 6 1.5 Aim and scope of this thesis 6 1.6 Outline of this thesis 6 2 Processes in a landfarm 6 2.1 Introduction 6 2.2 Presence of the contaminant 6 2.2.1 Equilibrium approaches 6 2.2.2 Non-equilibrium sorption 6 2.2.3 Influence of adsorption sites 6 2.3 Presence of micro-organisms 6 2.3.1 Degrading Organisms 6 2.3.2 Acclimation time 6 2.3.3 Threshold value of contaminants 6 2.3.4 Distribution of organisms in sediment and soil 6 2.3.5 Effect of temperature on activity 6 2.4 Presence of oxygen 6 2.4.1 Basic parameters of sediments 6 2.4.2 Volume changes of sediment during dewatering and ripening 6 2.4.3 Air filled pore volume in the sediment profile 6 2.4.4 Oxygen in aggregates 6 2.5 Modelling of processes in a landfarm 6 2.5.1 Description of the aeration model 6 2.5.2 Results of the aeration model 6 2.6 Conclusions 6 2.7 List of symbols 6 7 Landfarming of polycyclic aromatic hydrocarbons and mineral oil contaminated sediments 3 Chemical measures of bioavailability 6 3.1 Introduction 6 3.2 Definition of bioavailability 6 3.2.1 Conceptual definition of bioavailability 6 3.2.2 Operational definition of bioavailability 6 3.2.3 Definition of bioavailability in this thesis 6 3.3 Present use of chemical methods for bioavailability 6 3.3.1 Nutrients 6 3.3.2 Heavy metals 6 3.4 Requirements for chemical methods for measurement of bioavailability of organic contaminants 6 3.4.1 Measurement of total concentration of organic contaminants 6 3.4.2 Established methods for measurement of bioavailability of organic contaminants 6 3.4.3 Promising new chemical methods for measurement of bioavailability of organic contaminants 6 3.5 Chemical methods used in this thesis to establish bioavailability 6 3.5.1 Availability of PAHs 6 3.5.2 Availability of mineral oil, 6 3.6 Discussion and conclusions 6 3.6.1 Implementation of bioavailability 6 3.6.2 Bioavailability; definition and tools used in this thesis 6 4 Degradation and desorption of PAHs in sediments: kinetic approach 6 4.1 Introduction 6 4.2 Materials and methods 6 4.2.1 Degradation experiments (field) 6 4.2.2 Desorption experiments (laboratorium) 6 4.2.3 Calculation of rate constants 6 4.3 Results 6 4.3.1 Degradation of PAHs 6 4.3.2 Desorption of PAHs 6 4.3.3 Decomposition of organic matter 6 4.4 Discussion 6 4.4.1 Degradation and desorption 6 4.4.2 Degradation of PAHs and organic matter 6 4.5 Conclusions 6 5 Degradation of mineral oil in landfarmed sediments 6 5.1 Introduction 6 5.2 Materials and methods 6 5.3 Results and discussion 6 5.3.1 Composition of mineral oil in sediments 6 5.3.2 Degradation of mineral oil 6 5.3.3 Prediction of the degradation curve 6 5.4 Conclusions 6 8 Abstract 6 Effects of optimisation of landfarm treatment of sediments on bioremediation 6 6.1 Introduction 6 6.1.1 Optimisation on a landfarm 6 6.1.2 Dewatering 6 6.1.3 Forced aeration and higher temperature 6 6.1.4 Adding of substrate containing active fungi 6 6.1.5 Activation of microbiological activity in soil by vegetation 6 6.2 Materials and methods 6 6.2.1 Origin of the sediments and applied optimisation methods 6 6.2.2 Dewatering 6 6.2.3 Forced aeration and higher temperature 6 6.2.4 Adding of substrate containing active fungi 6 6.2.5 Activation of microbiological activity in soil by vegetation 6 6.2.6 Measurement of the fraction available for fast degradation 6 6.3 Results and discussion 6 6.3.1 Optimisation of landfarming versus passive landfarming 6 6.3.2 Effect of dewatering 6 6.3.3 Effect of forced aeration and higher temperature 6 6.3.4 Effect of adding of substrate containing active fungi 6 6.3.5 Activation

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