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Impact From Onshore Disposal Executive Summary - Topic Area 7.1 Det Norske Veritas The project objective is to determine the onshore practicalities and impacts of dealing with recovered drill cuttings, using technologies ranging from landfill to thermal recovery of oil, and to explore the potential for re-using the raw materials. The scope of this study follows recovered drill cuttings piles material delivered to the quayside, through landfill, processing options and subsequent disposal and re-use of end products. For each option, an evaluation has been undertaken of capacity, practicalities, environmental impacts and societal impacts. There is no experience of bringing onshore cuttings previously discharged to the seabed, thus the basis for considerations have been experiences with fresh cuttings coupled with data on old cuttings pile characteristics. Capacity and practicalities There are currently identified 10 operating and 4 developmental processing options in the United Kingdom (UK). In Norway there are 3 operating and 1 developmental processing plant. The total capacity of the identified processing options in the UK is estimated at about 300,000 tonnes a year, although their present processing rate of fresh cuttings is far less. The total amount of drill cuttings in the UK sector of the North Sea is assumed to be 2.9 million tonnes. If the UK cuttings are to be brought ashore for treatment and disposal this is assumed to be phased with field cessation (i.e. the 2.9 million tonnes will be spread over a few decades). The present UK onshore treatment capacity is thus theoretically sufficient to handle cuttings brought onshore. However, if all cuttings from one of the largest fields are taken ashore in one year, and all cuttings are to be processed, the capacity will be insufficient. Also, if the cuttings are coming in concentrated bursts rather that in an evenly flow capacity problems may arise. Proper planning and temporary storage is thus important to avoid such situations. The total capacity for the processing plants in Norway is estimated at about 120,000 tonnes per year. This capacity is considered sufficient for processing drill cuttings which could be brought onshore in Norway (assumed at 1.6 million tonnes with single field amounts at 30,000 tonnes). Today's processing methods are based roughly on 5 different technologies:  Thermal desorption, thermal distillation, solvent extraction, solidification and incineration/combustion. The conclusion that current capacity is sufficient for processing cuttings is based on experience with fresh cuttings. The introduction of old cuttings into the feed stream is assumed to cause some difficulties due to the varying chemical and physical characteristics among the piles and even within any given pile. Most processes are susceptible to even minor changes in quality of input material. Other uncertainties which could influence processes, especially those that are thermal, are particle sizes (fines) and wettability properties of the material. For the possible reuse of solids, the content of chloride, various chemicals and heavy metals are often limiting factors. Although these factors are problematic, they can be addressed by applying available technology, albeit at elevated costs in some instances. In UK 50 landfill sites accepting oily waste were identified, and the total capacity of these is estimated at 360,000 tonnes per year of sludge and 1.5 mill tonnes per year of solids. Landfill capacity is thus theoretically not a limiting factor in the UK. However, if the waste is being disposed of directly without treatment it could be classified as sludge, and capacity will be limited. Pre-treatment for lowering the water content or processing will then be preferable as to classify the waste as solid. In Norway 19 landfill sites (in relevant geographical areas) have been identified which either accept oily waste or would consider using this material as covering/capping material on their disposal sites. The total capacity of these relevant landfill sites is estimated at 360,000 tonnes processed cuttings per year. There is a significant discrepancy in the regulations for disposal of oily waste to landfill in the UK and Norway. In the UK there is no defined limit for oil content of wastes which can be disposed of to landfill, whereas the regulations in Norway are more prescriptive. In the UK, the type of waste that can be disposed depends on the licensing conditions of specific landfill sites and the decision of the regulatory authority on appropriate disposal routes for specific wastes. In Norway, no waste containing more than 0.5 % by weight oil can be deposited in landfill sites. If the waste has an oil content between 0.5 and 2.0% it will be transported to a special waste deposit at Langøya (abandoned limestone quarry) for final disposal. If the oil content exceeds 2 % by weight, the waste will have to be exported or burnt in the cement kiln at Brevik. After treatment at a processing site in the UK the oily waste is assumed not contain more than 1 weight percentage oil. However, in the UK cuttings may be disposed of in landfills without any processing if they meet the landfill specific requirements. In Norway the cuttings have to be processed prior to disposal to meet the regulations. Currently in the UK there is no regulatory framework to specifically address the landfarming of drill cuttings. Technically, this is an option that could be used for disposal of the drill cuttings as microbial action could break down the hydrocarbon content over a period of time; in practice this would involve negotiating with regulatory authorities through the planning process to assess the feasibility of this option. Landfarming is not permitted in Norway. A high content of salt will eliminate landfarming as an option. The average processing costs in the UK are estimated at £192 per tonne (£153 - 250), and this is almost double the processing costs in Norway (estimated at £100 per tonne). The reason could be that Norwegian plants have been running for some years, and as such are more settled both with regard to experience and continuity in delivery of cuttings. Another aspect could be electricity cost which is lower in Norway. For disposal costs the situation is reversed - the Norwegian costs for disposal could be more than double the cost in the UK. In the UK disposal cost is dependent on type of waste. Average costs for transporting and disposing of sludge are estimated at £39/tonne and the average costs for disposing of solids are estimated at £24/tonne. Additional landfill tax will be £2/tonne for processed inactive waste and £11/tonne for unprocessed active waste. In Norway it is usual to operate with one disposal cost, not dependent on waste structure. The average cost for Norway is estimated at £79/tonne. The reasons for this difference could include more competitive conditions in the UK, better infrastructure in the UK, stricter disposal requirements in Norway, etc. In the UK, the distances between most frequently used ports and processing sites, ports and landfill sites and processing sites and landfill sites vary significantly. It is an advantage that 4 of the most used ports in the UK are located in Scotland where the majority of the operating processing plants are also located. However, there are no landfills in Scotland licensed to receive oily cuttings which could lead to long distance transportation requirements. In Norway, all processing plants are located on the south-west coast of Norway, and landfill sites accepting oily waste are located nearby. Furthermore, all plants are also located very close to port facilities. Therefore transportation requirements once the cuttings are onshore are not as extensive as in the UK. Reuse opportunities Waste streams from processing have a potential for different reuses. For most alternatives however high salt content will limit this opportunity, and a salt washing process is necessary. This will add costs and make the process more complex. A clean solid residue could be used in construction materials, and possibly in road cover materials depending on chemical content, particle size distribution etc. The greatest potential for reuse of solid residues is considered to be as covering masses on landfills. Many landfills have a demand for such material, but the solids chemical contents (including trace metals) and costs (e.g. transportation) could reduce this potential. Recovered oil is assumed to consist of a variety of fractions with chemical impurities. Reuse in drilling mud is therefore not considered practical. Depending on quality it could possibly be sent to refineries for refining together with crude, or more likely it could be burnt as fuel in the processing plant. An option to use whole cuttings as fuel for coal fired power stations has also been raised. We assume a high organic content will be necessary to make this cost efficient, but the idea has some potential. Environmental impacts As there is no experience with processing or disposing of "old" cuttings onshore, the impact evaluations are based on experiences with fresh cuttings and assumptions related to old cuttings. For all types of processing and/or disposal strict requirements and regulations are presumed and no acute spillage situations are considered. For processing cuttings there will normally be some emissions to air from the process or from associated utilities (energy supply etc.). Some emissions will also arise from transport, depending on type and distance. Stabilisation methods will not emit much, but will utilise some resources and increase the volume for disposal (by about 20%). Old cuttings are assumed a source of odour, and this is experienced with some processes for fresh cuttings. Dry solid fines from some processes may represent a potential for spread of dust, which could be a local nuisance. Some processes would also be noisy, and location relative to settlement is therefore of importance to avoid problems. Environmental effects from land disposal of cuttings depend on many factors such as cuttings characteristics and the design and quality of the landfill. Most landfills have strict regulations with regard to leachate water and emissions, and continuos undertake monitoring. Many landfills also collect methane which is flared or utilised. Given the strict regulation for landfills, cuttings disposed there should not represent significant negative environmental impacts. Without having assessed individual landfills we presume that landfills allowed to receive waste with an oil content to 35% have very strict conditions of operation. Such issues have to be assessed for actual landfills when relevant, as local conditions related to environmental sensitivity could be of great importance. Societal impacts No significant negative impacts on local society are identified. Positive effects such as new employment and business in new areas will be very limited if any. From a societal point of view increased pressure on landfills from a new waste source may be considered negative. For the UK the increase related to total waste volume will be about 1% if all cuttings are disposed of in one year. Split over a realistic number of years and compared with total oily waste disposal only the increase will be more significant (5-10% assuming an even flow of cuttings for disposal). In Norway the increased volume will show even on the total annual waste statistics.