Warrington Clinical Waste Treatment Centre Appeal Proposed Outline Evidence of Alan Watson

2. The application and the proposed incinerator

13. 
    The relevant details of the application are largely addressed in the Statement of Common Ground between UBB and GlosVAIN (CD4.9) and are not repeated here save for a few key facts with associated commentary which are of particular relevance to this evidence and help to set a background to the following chapters. This includes information on mass balances and production of residues which is missing from the planning application and which has been derived particularly from the Environmental Permit application and permission.
    
14. 
    The main incinerator building would be 236 metres long, between 55 and 25.6 metres wide, and up to 48 metres high. The stack would be located adjacent to the western elevation of the building and would be 70m high with a diameter of 2.5m.
    
15. 
    The application is founded on the proposed plant burning of non-hazardous residual waste the majority of which would be municipal solid waste from Gloucestershire. The application indicated that a smaller proportion of commercial and industrial waste would be treated. This should also be sourced from Gloucestershire. In both cases only waste which is not recyclable or compostable and which would otherwise be landfilled should be treated.
    
16. 
    An Environmental Permit, ref EPR/CP3535CK/A001, was issued by the Environment Agency on 22^nd May 2013.
    
17. 
    The design electrical output would be 17.4 MW of which 14.5 MW would be available for export with the remainder being used parasitically to run the incinerator. This represents a basic thermal efficiency of c.22.7%¹ as can be seen from the Sankey diagram accompanying the Environmental Permit R1 application²:
    

18. 
    There are no buildings or processes requiring a heat load in the immediate vicinity of the proposal. Nor is there any evidence of expressions of interest in using heat from the facility.
    
19. 
    In spite of this the schematic diagram of the proposed Incinerator in the application to the Environment Agency and in the Decision Document³ optimistically – and misleadingly - includes a heat exchanger (which is understood not part of the current proposals) and a supply to heat users – also not included in the current application:
    

20. 
    In fact the only CHP schemes in the UK associated with incinerators are those which have been designed and operated as such from the outset. In this case it is therefore considered that there is little or no realistic prospect of combined heat and power operation in this location.
    
21. 
    The Environmental Statement states⁴ that: “the plant throughput in any year is a combination of three factors:
    

 thermal capacity;

 waste CV; and

 plant availability”.

22. 
    The thermal capacity of the grate is fixed and this, together with the limitations of mechanical handling equipment and effective ‘burn-out’ on the grate effectively restrict the operating range of the incinerator and reduce it’s flexibility to deal with major fluctuations in the nature of the waste stream. This makes it a particularly poor choice of technology for managing waste in a time of great change and uncertainty.
    
23. 
    In the case of Javelin Park the capacity of the proposed incinerator is generally reported in the application documents as 190,000 tpa with a net calorific value of 9.65 MJ/kg but it is noted that in the engineering design drawings the capacity is reported as 23.1 tonnes/hr (c.185,000 tpa) with a calorific value of 9.94 MJ/kg.
    
24. 
    The plant would have the capacity to burn approximately 190,000 tonnes of waste per year with an availability of 91%⁵ or 7,972 hours⁶.  Operating at higher availability would increase the annual tonnage of waste. Conversely reducing availability would reduce the annual throughput.
    
25. 
    Most applications include a stoker capacity diagram which clearly illustrates the operating range of the incinerator. UBB has not, unfortunately, included this diagram with their application but an example from another, rejected, incinerator application in Plymouth by Viridor is included below. This was a more flexible twin line proposal and the stoker diagram relates to a single line with a capacity of c.140,000 tonnes based on a design calorific value of 9,360 MJ/kg:
    

26. 
    The Stoker capacity diagram shows that incinerators can only operate if the throughput rate and the calorific value of the feedstock remain within a fairly narrow range. The Nominal Design Point is a municipal waste throughput of 17.6 tonnes per hour at a Lower Heat Value⁷ (‘LHV’) of 9,360 kJ/kg which is equal to a thermal input of 45.8 MW. The municipal waste LHV range can vary from 7,000 kJ/kg up to 14,000 kJ/kg. Municipal waste with a LHV below 7,000 kJ/kg can be incinerated only with the support of auxiliary fuel.
    
27. 
    There are constraints on the operating ranges in terms of plant inputs / outputs and efficiency. If the calorific value of waste rises above 9,360 kJ/kg then throughput must be progressively reduced from 17.6 tonnes/hour @ 9,360 kJ/kg to about 11.6 tonnes/hr @ 14,000 kJ/kg. If waste calorific value falls below 9,360 kJ/kg then there is only a small mechanical over-load, of 1.8 tonnes/hour, possible. If waste calorific value falls below 9,360 kJ/kg then the heat input to the incinerator falls as would the electrical output.
    
28. 
    It is important to be confident, therefore, that the quantities and calorific value of the waste would fall within the operating parameters of the Stoker diagram, and ideally be close to the ‘nominal point’ over the lifetime of the facility.
    
29. 
    The experiences of Veolia with their application in Sheffield provides a warning to how failure to address the waste stream properly at the application stage can prejudice local management of waste in the future and increase transport distances.
    
30. 
    When the original application was considered for replacing the Sheffield incinerator in 2001 the capacity was tested against higher recycling rates, up to 45%. It was argued that, if MSW was to reduce, the capacity gap could be filled with up to 80,000 tonnes of commercial waste. When this actually happened, just 7 years later in 2008 Veolia argued that this level of commercial waste presented a problem.
    

Bottom ash Generation:

31. 
    The engineering drawing⁸ for the proposed boiler shows the design mass flow rates of bottom ash (‘slag’) @ 5,300 kg/hr (equivalent to c. 42,400 tonnes/year) and for boiler ash @ 212 kg/hr (equivalent to c. 16,960 tonnes/year). This means that the plant would be producing a total of 59,360 tonnes of residues.
    

32. 
    These flows seem to be significantly higher than those in the application – shown for example from the WRATE model⁹:
    

33. 
    This indicates that a total of 39,999 tonnes of bottom ash including metals would be produced. Engineering drawings are, however, generally considered to be more reliable sources of design information than the supporting text and models in a planning application. It therefore appears that the generation wastes and residues may be significantly greater than have been modelled or assessed as part of the application.
    
34. 
    Besides the production of large quantities of ash the incinerator will also consume significant quantities of raw materials including 200,000 l/annum Fuel oil; 800 tonnes/year Ammonium Hydroxide; 2,400 tonnes/year Hydrated Lime; 70 tonnes/year Activated carbon and a (‘nominal’) consumption of 32,000 tonnes/year of Process water.
    
35. 
    These do not seem to have been included in the Environmental Statement but are listed in the Environment Agency decision document on the Environmental Permit¹⁰.