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Executive Summary 7 Assessment of Offshore and Onshore Handling, Transport and Treatment Options for Lifted Cuttings Material This report is part of the UKOOA Drill Cuttings Research JIP Phase II and assesses and compares the various options for treatment of removed cuttings and associated water. Both offshore and onshore treatment options are considered. In total six treatment options were identified from the previous UKOOA JIP Phase I reports and consultations with industry as follows: Option 1:   Separation offshore, treatment and disposal of solids and liquids offshore. Option 2:   Separation, treatment of liquids offshore, transport and treatment of solids onshore. Option 3:   Separation, treatment of solids offshore, transport and treatment of liquids onshore. Option 4:   Separation offshore, transport onshore treatment of both solids and liquids. Option 5:   Injection of cuttings. Option 6:   Transport of slurry to shore, separation and treatment onshore. These options were compared using a high level Best Practical Environmental Options Study assessments method, which is based on technical, environmental, cost and health and safety performance. The results of this assessment suggested that no one option was obviously superior and all had some significant drawbacks. Options 1 and 3 were not considered viable due to the deposition of treated solids on the seabed and restrictions on offshore solids treatment equipment. Option 4 is logistically complex and is considered impracticable. Option 5, cuttings injection was overall the most attractive option which is estimated to be viable at 25% of UKCS installations. However, the injection of lifted cuttings is not currently legal in UKCS waters. Option 2 is logistically complex and likely to be constrained by weather but was considered potentially viable providing legal constraint can be resolved. Option 6 was the only option which is viable and legal but some aspects of the technology have not yet been proved in the context of cuttings recovery and removal. Onshore impacts due to cuttings treatment and the availability of treatment facilities are major constraints provided the rate of cuttings generation is managed to avoid excess demand. The viability of Options 2, 5 and 6 could be improved by the following: changes to legislation; development and testing of offshore water treatment and cuttings handling equipment, and investment in onshore cuttings treatment facilities for the separation of solids and liquids. The specific circumstances of pile removal and treatment operation would be very different and a Best Practical Environmental Option (BPEO) study would be required in each case. A number of specific questions regarding the energy consumption, costs and feasibility of cuttings handling, treatment and disposal were raised from Phase I reports 7.1 and 7.2 and these are dealt with below: 1. Relating to reinjecting slurry offshore How much would reinjection cost? £390/MT What is the energy consumption for reinjection? 1.1 GJ/MT 2. Relating to reinjecting water offshore and shipping solids to shore How would water be best separated from solids offshore? Mud shakers and screens How would solids be shipped back to shore e.g. skip and ship vs bulk loading to dedicated vessel? Currently, skip and ship is only the proven marine transport method 3. Relating to shipping slurry to shore, treating and disposing water How would water be best separated from solids onshore? Mud shakers and screens How would the water be treated? Onshore production/ballast water treatment facility eg Nigg Oil terminal (Cromarty Firth) What are the discharge standards for the separated water? Dependent on individual facility licence agreement (typically 5-15 ppm hydrocarbons) How would slurry be shipped back to shore e.g. skip and ship vs bulk loading to dedicated vessel? Trailer dredgers (range from 1000-30,000 m3 capacity) are designed to transport slurry and liquids and can be equipped with a dynamic positioning system How much would shipping slurry to shore, separating, treating and discharging the water cost? £440/MT What is the energy consumption for shipping slurry to shore, separating, treating and discharging the water? 3.4 GJ/MT 4. Relating to disposal of oily solids Where, today, could the oily solids be land-filled? In the North East of Scotland currently, Stoney Hill landfill near Peterhead, other licences are under review Could a purpose built special waste land-fill facility be constructed? A site with suitable geology and management could be dedicated for special waste, subject to licence requirements eg Stoney Hill What would be the long-term impact of the oily solids in the land-fill site? Providing the facility is correctly maintained, contamination outside the site is unlikely How much would disposing of the oily solids cost? Approximately £150/MT for landfilling untreated cuttings (includes transport costs from quayside to landfill facility) 5. Relating to treatment and disposal of solids What processes could treat the oily solids? Direct/indirect thermal desorption or solvent extraction onshore and, grinding with thermal desorption offshore What existing plants could treat the oily solids? Total Waste Management Alliance and Oil Tools (Aberdeen, Peterhead and Lerwick), Maersk and Scotoil (Aberdeen) How is the oil disposed of? Can the oil be re-used? Oil is currently reused as fuel for the thermal treatment process, as a base for fresh drilling muds (oil from residual cuttings may be weathered and unsuitable for reuse in drill muds) or, reconditioned for use as fuel for power stations and quarry operations What would be the long-term impact of the cleaned solids in the land-fill site? Similar to that for oily solids providing site is correctly managed How much would treating and disposing of the cleaned solids cost? £257/MT (includes treatment, transport to landfill and disposal costs) What are the throughput capacities of existing facilities (compared with the volume to be treated)? Currently, treatment capacity is greater than volume to be treated What is the energy consumption for treating and disposing of the cleaned solids 2.3 GJ/MT (includes treatment and transport to landfill) 6. Relating to treatment, disposal of oil and re-use of solids What re-use opportunities are there for cleaned solids e.g. Scotoil cat litter project? Cleaned solids are currently used as a liner and cell wall building material in landfill sites, Scotoil propose to use the cleaned cuttings as an absorbent base material for cat litter.