Graham Ellis of Rye Sustainable Living Forum organised a trip to the Newhaven Energy Recovery Facility, which takes all our non-recycled domestic waste. The facility is in effect a large incinerator which uses the heat from burning up to 210,000 tonnes of waste per year, to generate electricity for the National Grid to power about 25,000 homes.
The facility was seen as controversial prior to its construction in 2008. The Rother Environmental Group was concerned that the facility would necessitate a constant flow of waste over its lifetime, at the expense of recycling programmes. In the event, there has never been a shortage of waste to burn since its completion in 2011 and doesn’t in itself prevent increased recycling. The Veolia contract runs until 2033 and the lifespan of the facility is a maximum of 50 years.
One of the most reassuring things to report is that at no time has the facility been used to burn waste collected for recycling. None of what you put into your recycling bin will be burnt, other than what is rejected in the Materials Reclamation Facilities (see previous article).
About 58% of all the waste we produce is turned into energy in Newhaven, with 41% being recycled or reused and just 1% going to landfill. In practice, these figures have barely changed in the last 10 years. Sadly, there appears to be a ceiling to recycling.
The facility manager, Martin Micallef, together with Steph of Veolia South Downs Ltd, took us on a tour of the facility that employs 36 staff. It’s a neat design, certainly compared to the rather ramshackle recycling and storage depots along the access road. The whole site is surrounded by a bund, to 5m above sea level, and is part of the Newhaven flood protection. All the rainwater is stored on site and used for quenching the ash.
The waste arrives for the most part in large 23 tonne capacity articulated trucks from waste transfer stations across the county. The tipping hall can take up to eight of these at a time, although in practice there are always fewer. Some waste also arrives in street cages and trucks. Each day it’s about 650 tonnes that is delivered. Most of that is from homes in East Sussex, although there are some commercial companies using the facility too. When we were there, a truck from Gatwick airport was emptying its load.
The whole facility operates at negative air pressure, to ensure no dust or contaminants escape. 160,000 m3 of air is drawn in per hour, and a megadoor is fitted to the reception hall to minimise the escape of air.
Surprisingly, part of the facility is below ground, to a depth of 20m. That allows for a large bunker to fill with waste, with a 4000 tonne capacity, creating a buffer that can allow for outages as well as peaks and troughs in waste supply. Unsurprisingly, there is more waste after Christmas, with a low period in March. Every three months, the waste is surveyed to find out what changes are occurring in the waste streams.
Two relatively new waste streams are a concern
Disposable E-cigarettes, or vapes, can burst into flames at any time prior to arrival at the facility. They have caused a significant rise in fires at waste transfer sites and recycling plants around the UK, releasing toxic fumes into the environment in the process. Well over a million disposable vapes are thrown away each week in the UK, with many of them find their way into general waste. When broken, their lithium-ion batteries can easily catch fire. AVD (a pioneering fire extinguishing agent) fire extinguishers can be used to put out these fires.
The other risk is explosions of gas bottles and canisters, in particular resulting from the rise in the use of nitrous oxide, popularly referred to as laughing gas, as a recreational drug. Veolia UK experienced more than 25 serious incidents of explosions and damages at energy recovery facilities last year due to discarded canisters, costing the company £1.4 million from outages and repairs.
Thankfully the boilers are very tough – 120 bar pressure tested – so most explosions do not close down the facility, they just pause the process before the gases can stabilise.
Other than removing some gas bottles, the waste is not sorted before it is poured into the holding pit. A manually operated claw is used to mix the waste to allow an even burn.
The process
Waste is fed into a chute with a ram feeder into the furnace where it combusts. It is combined with pre heated oxygen to produce ‘syngas’, to allow for a full combustion. Ammonia is injected at this point as this helps break down the NOx gases (nitric oxide and nitrogen dioxide). The heat at one point exceeds 850 degrees, to allow for a full breakdown of all materials. High risk medical waste is not treated here, as the temperatures need to be even higher, so need sending to a specialised incinerator.
The hot gases from the furnace travel through a boiler, heating water that runs through pipes to create steam. The steam spins a turbine to generate electricity, of which 16MW/hr is then exported to the grid. 2MW/hr is used on site for running the fans and all the other electrical equipment of the facility.
Incinerator bottom ash (IBA) is the noncombustible residue left over after waste is burned in an incinerator. It’s a complex mixture of irregularly shaped particles that can include metals, rubble, concrete, minerals, ceramics, and glass. IBA can also contain heavy metals, organic compounds, and other toxic contaminants. This is treated to remove contaminants and reused as an aggregate in construction.
Control of pollutants and safety
The exhaust combustion gas is highly acidic, so 3 tonnes of lime is added during the process to neutralise these gases, help remove sulphur dioxide and other contaminants. There is a whirlwind within the reactor that binds the acids to the lime. These are then removed as a solid ash known as Air Pollution Control Residues (APCr). These are hazardous and have a high pH, heavy metal content and persistent organic pollutants such as dioxins. At Newhaven, these are containerised in bespoke bags – Martin calls them Gucci bags because they are so expensive – to then have them transported by train to have them securely stored at Minosus – Veolia’s underground storage facility at a salt mine in Cheshire. Newhaven ERF generates about 6000 tonnes of this difficult waste per year.
Processes are also in place to remove ferrous metals from the ash pit, as well as aluminium.
The emissions to air of the facility through its twin stacks are very tightly controlled. Until last year 10mg/m3 of air dust particles were permitted, this reduced to 5mg/m3 last year. The actual emissions from this facility are 1mg/m3, five times lower than the permitted maximum.
The steam at the end of the process amounts to 80 tonnes per hour, where it is cooled to condense back into liquid water.
The facility runs at 100% capacity all the time, with planned outages every 2 years, at which time all the hotels in Newhaven get booked up to accommodate all the contractors carrying out maintenance.
It was reassuring to see how thoroughly the automated process is monitored, with the gas being analysed instantly at every point in the process and banks of screens.
One aspect of the visit that made for it being a bit stranger than necessary was a testing of the public address system which went on for an hour ‘Attention please, attention please…’. It was just bad luck that this once a month test was happening during our visit.
A frustration for me was seeing just how much waste is being incinerated that has the potential to be recycled, if only we the consumers could make the effort to separate it out better when we can.
By Dominic Manning
Article featured in Rye News 2nd August 2024
