Teesside Ef W Plant - Operations

Operations

The station operates constantly, burning municipal household waste from the local councils of Stockton-on-Tees, Hartlepool, Middlesbrough, Redcar & Cleveland, North Tyneside and Northumberland. When there is a shortfall in household waste, non-hazardous industrial and commercial waste are used to make up capacity. The station burns only residual waste, which is material left over after recycling. The incinerator operates 24 hours a day, seven days a week.

Waste is delivered to the station by road, using up to 100 waste collection vehicles. Up to 2,800 tonnes of waste a week or as much as 1,000 tonnes of waste a day, can be delivered at the plant. A rail head was also built on the railway sidings adjacent to the site in 2009. This allows for waste to be delivered to the plant by rail, rather than just by road. This is more sustainable as it reduces the amount of traffic on local roads. In December 2011, it was announced that the rail head would be used to receive up 500,000 tonnes of residual waste per year from Merseyside via a rail waste transfer facility at Knowley Industrial Park, Kirby, in a contract worth £400 million.

Waste arriving at the plant is checked in and weighed, before being delivered to the plant's reception hall. The large reception hall allows the vehicles to dump their waste safely. Air for the combustion of the waste later in the plant is drawn from the reception hall so that odour and dust doesn't pollute the building's surroundings. From the hall waste is tipped into a large concrete bunker. Here the feedstock is homogenefied by a crane operator, who mixes and removes unsuitable waste. A grab crane then manoeuvers waste from the bunker to the hoppers that feed the furnace. This crane is operated from a control room. This room also monitors the equipment in the plant, the combustion gases and maximises the efficiency of the plant.

From the hoppers, the waste falls onto the furnace-charging chute and from there onto the incinerating grate. Here it is burned at a temperature in excess of 1,200 °C. This heat is then converted into super heated steam through the plant's boilers. This in turn powers steam turbines, much in the same way as a conventional thermal power station. Electricity is generated at 11 kilovolts. After exiting the turbines, the steam is condensed back to water. For the original two incinerating lines use river water from the Tees as a cooling medium, whereas in the third line, water is condensed through air cooled condenser. The cooled water is treated and reused in the boilers.

Gases from the furnace are cleaned using selective non-catalytic reduction (SNCR), spray absorbers and active carbon injection. These processes remove nitrogen oxides, acidic gasses, dioxins and heavy metals from the plants emissions. The remaining gases are passed through fine-fabric bag filters to remove and solid particles, before it is released from the chimney. Each incineration line has its own independent stack in the chimney, and the flue gases are continuously monitored before being released. This information is relayed to the control room. The remaining fly ash from the filters contains particles from the incineration, lime from the spray absorbers, salt and carbon dust, and so is stored in a sealed silo until it is taken from the site for disposal. Incinerator bottom ash left on the incineration grate after the burning is moved by converyor to a bunker. Whilst on the conveyor, a magnet removes ferrous metal from the ash for recycling. The remaining ash is then used as an aggregate in the construction industry.

A recycling centre operates next to the plant, which opened in December 2001. In 2006 a composting facility was opened.