Frequently Asked Questions
WHAT TYPE OF TECHNOLOGY IS PROPOSED?
PREL proposes an integrated resource recovery facility to meet local community and Authorities’ Landfill Directive targets. The facility would use the following technology types:
- Separation equipment (Advance Mechanical Recycling)
- Gasification with 2nd stage high temperature combustion (Biomass Power Ltd gasification modules)
- Tetronics plasma vitrification
- Electric Arc glass furnaces (optional)
- Gortex ™ filtrations systems
- Concrete batching equipment (optional- CONECO or equivalent)
- In vessel or enclosed windrow composting with gas and leachate capture and destruction (Optional – enclosed negative pressure atmosphere)
- Industry Standard flue gas scrubbers; Low temperature acid gas scrubbing, SNCR scrubbing and activated carbon systems for heavy metal and organic contaminant removal
- Flue gas recirculation
- Steam turbines and boiler sets
- Waste heat recovery systems using off the shelf heat pumps
- Sealed containers with tracking systems
IS IT A PROVEN TECHNOLOGY AND ARE THERE ANY REFERENCE PLANTS?
All elements of the integrated facility can be found operating around the world and the technology is proven. Biomass Power Ltd has had three working plants operational in the UK since 2006 and one under construction in Italy (2011). Tetronics plasma is in use in the UK, Italy and Japan and has years of operating data.
The company has achieved environmental and UK Section 36 planning consent (obtained 2009) to build a large facility in Peterborough.
WHAT NUMBER AND SIZE OF PLANTS ARE NEEDED FOR A TYPICAL LOCAL AUTHORITY?
PREL EnergyParks have a modular configuration and may be specified according to the number of gasifying combustors required, the waste to be converted to energy or the amount of energy production needed. Each unit has an annual capacity of approximately 39,400 tonnes. The choice of plant size will have to be decided against the background of waste available after recycling operations, distance to waste sources, availability of water for cooling, transfer stations and transport routes, distribution for electricity produced and local area conditions.
For a “typical” county, the need might be initially for one main facility and recycling precinct with a network of transfer station / recycling centres of various sizes.
CAN THE TECHNOLOGY HANDLE ALL OF OUR RESIDUAL MUNICIPAL WASTE INCLUDING HAZARDOUS AND CLINICAL WASTE?
No. The plant’s combustion system is designed for non-hazardous wastes and will be permitted by the relevant bodies as such. However, the plasma units are capable of meeting and processing hazardous materials and indeed are used to do so by recycling the fly ash and Air Pollution Control (APC) residues, along with energy saving light bulbs and some batteries. The plants will not be allowed or designed to take external medical, nuclear, radioactive or explosive materials.
DOES THE SOLUTION ENCOURAGE RECYCLING/COMPOSTING?
Yes. This is an 100% recovery and recycling solution, catering also for composting of clean green waste and food waste to fertiliser.
These are options that can be included where a need is identified. These options are dependent on the availability of clean green waste, un-contaminated food wastes and local demand for the output.
PREL recycling and transfer stations will handle construction and demolition waste, recycling up to 95% (when combined with a PREL EnergyPark facility).
In addition, transfer stations offer the easy and hassle free option to encourage residents to bring their waste to PREL facilities rather than fly-tip. They can become the focus for localised recycling efforts.
Secondary factors include the development and promotion of high quality recycled materials, improving demand, understanding and market share for recycled materials. The knock on effect is that more people buy recycled materials with a known, safe recycling system and the quantity of virgin materials made from earth minerals is reduced as a result.
IS PRE-TREATMENT AT THE HOUSEHOLD / BUSINESS LEVEL REQUIRED?
Not from a plant operations perspective, as all mixed waste will go through a separation plant. The company would always encourage people to re-use what they can and where they can.
WHAT ENERGY RECOVERY IS POSSIBLE?
This is a key part of our process and the vast majority of energy recovered is renewable, attracting Renewable Obligation Credits (ROCs). The plant is an efficient energy recovery system. An 18 unit plant is capable of creating electrical energy (circa 80 Mega Watts) as well as opportunities to use recovered low grade thermal energy for localised district heating, glass houses and heating / chilling industrial spaces.
As with all Rankin Cycle thermal power plants, a considerable amount of waste heat has to be disposed of, primarily via cooling towers. If the plant is located within one kilometre of a centre of population the option is available for providing a district heating service, similar to those established in continental Europe or use adsorption chilling systems to create cold stores.
WHAT HAPPENS TO THE MATERIAL THAT CANNOT BE TREATED OR IS LEFT OVER AFTER TREATMENT?
There is no material that is acceptable to the plant that cannot be treated to enhance its value or utility. Nothing leaves the plant to be disposed of by landfilling.
The immediate fate of materials falls into one of five categories:
- Material recovered or recycled at the transfer station
- Bed ash recovered and classified for use as a construction filler or soil additive
- High temperature fly ash that accumulates at the cyclones for use as an enhanced cement replacement in concrete
- Low temperature fly ash trapped at the Baghouse (to be vitrified and used in making glass products, recycling of metals, the production of acids and materials for market)
- Direct entry to the vitrifiers for toxic and hazardous waste (lightbulbs, batteries) for recycling and recovery of materials
WHAT FLEXIBILITY OF LOCATION AND TREATMENT CAPACITY DOES THE PLANT OFFER?
Being modular, the plants can readily be configured to accommodate the available waste stream quantum.
Each combustion line is a stand-alone unit connected to common plant services and control systems. Downstream plants such as turbines, vitrifiers and waste handling equipment are standard commercial items, supplied to meet the output from the chosen number of combustion units.
The element of scale is absolutely critical to effective ongoing facility operation. There are numerous instances around the world of waste treatment processes being shut down completely for maintenance to be carried out, compromising the financial viability of the plant and associated by-product industries that rely on the plant for power and raw materials. This completely undermines the overall sustainability of the process.
Site requirements, which are not overly demanding include:
- A minimum site size of 6 – 15 hectares on a flat site
- A water supply capable of delivering 1m3 per hour per combustion line or 7884 m3 per year per line, for cooling tower and process water (can be sewage effluent)
- Adequate road access
- Access to the local electricity grid
- A market for the recovered and re-manufactured saleable output
Water requirements can be made up from sewage water recycling but access to “town’s water”, a river or seawater for cooling water is helpful.
WOULD THE TECHNOLOGY REQUIRE COLLECTION SYSTEMS TO BE MODIFIED?
No, but efficient use of containerisation will be encouraged and the ability to compact off-site and at transfer stations can result in improved recycling and environmental standards during collection rounds. This could be achieved by using lighter electric powered collection vehicles for household waste. Multi-body vehicles could also offer greater sort-at-source services, improving awareness and take up of recycling schemes.
The plant transfer station can handle loose waste as delivered by standard city compactor trucks, bulk industrial/construction waste and bulk liquids. We anticipate that waste from the area close to the main plant would be delivered in this manner.
IS THE TECHNOLOGY FLEXIBLE ENOUGH TO MEET ANY FUTURE CHANGE IN LEGISLATION?
The plant has the exceptional ability to meet any reasonably foreseeable changes in emissions legislation and fits extremely well with government objectives of moving to a low carbon economy.
The plant technology has been designed to meet and surpass current legislation, particularly that relating to emission and pollution regulations. All aspects of the technology are under full computer control and the process can be varied, for instance, to modulate the calorific value of the firing and the rate of injection of flue gas scrubbing reagents.
If necessary, whole units such as boilers, economisers, and baghouses can be removed and new or modified units installed. Ancillary plants within the complex are generally modular or bolt-on/bolt-off. This allows modifications to be made in a very short time frame. Redundancy within the system means that if modifications are required to meet legislation they can generally be made without compromising waste throughput.
The system is capable of running solely on energy crops, should the necessary quantity be available. So if the community we serve suddenly stopped producing waste, the plant would remain viable.
HOW FLEXIBILE IS THE PLANT TO MEET ANY FUTURE CHANGE IN WASTE STREAMS?
Our flexibility enables the plant to generate revenue from not only waste management, but electricity, renewable energy credits and by-product streams through the recovery and recycling process.
On this basis, waste minimisation does not have the detrimental impact on revenues as it would with landfill or other processes
We encourage councils and communities to look beyond immediate legal obligations and requirements and to consider the waste management needs of industry when it makes its own choices regarding provision of waste management services. In doing this with buy-in options to the facility, PREL can reward waste minimisation for local councils. We actively encourage waste minimisation to improve environmental quality.
The EnergyPark facility is designed to be versatile with regard to composition, energy content and presentation of fuel derived from waste.
WHAT ENVIRONMENTAL HEALTH ISSUES ARE THERE WITH THIS TYPE OF TECHNOLOGY?
The PREL solution is an exceptionally clean process. There are no adverse environmental health issues of any significance associated with our facility.
PREL is serious about having the cleanest, most efficient process and we undertake to make available information about known impacts to health and reduce these to the lowest practicable levels.
The older generation of “incinerators” had a well-deserved reputation for pollution and generally inefficient management and were rightly criticised by environmental organisations. Over the last 15 to 20 years we have seen a dramatic improvement in all aspects of energy recovery technology, from waste handling pollution control to overall plant energy efficiency. We know our facilities easily exceed all applicable EU regulations and environmental standards.
WHY IS THE PROPOSED SOLUTION SUITABLE FOR MY AUTHORITY/ COMMUNITY? DOES IT FIT IN WITH THE LOCAL WASTE STRATEGY?
PREL offers a world class solution that fits with most, if not all waste and planning strategies.
This is demonstrated as follows:
- Meets the landfill directive (a requirement of the strategy)
- Provides additional recycling credits that would normally not be possible with other residual treatment plants (assists meeting high recycling rates)
- Deals with municipal wastes and provides options for the commercial, industrial and agricultural sectors of the community
- Fits with the national waste strategy
- Can meet proximity principle guidelines
- An affordable, reliable solution that is adaptable to council need
WHAT COUNCIL & COMMUNITY INVOLVEMENT IS REQUIRED IN THE PLANNING APPLICATIONS PROCESS?
Ultimate responsibility for progressing the planning applications must rest with the developer. However, given the level of risk involved by the contractor, the application cannot proceed without a clear indication of the intent of the relevant Council and community.
PREL welcomes community and Local Authority involvement in the planning process at national, regional and local level.
The precise mechanism of involvement would need to be determined in each specific case.
In order for PREL to proceed though, it would engage in public pre-application consultation to gauge the suitability of any sites and understand the direct community and council view to help shape and inform any planning application. Councils and Local Authorities are not required to be a party to any development. EnergyParks are fully capable of being a completely Merchant facility but there are significant local benefits that can be passed through to councils that use the facility.