Knostrop Clinical Waste Incinerator

Clinical Waste Incinerator operated by SRCL and located adjacent to Knostrop Treatment Works, Leeds, with an annual throughput limit of 17,000 tonnes.

Knostrop Clinical Waste Incinerator
Site Location See HT & Clin → page for a larger UK Wide map.
Waste Licence	CP3930XL
Operator	SRCL
Operational Capacity	17,000tpa
Number of Lines	2
Region	Yorkshire and Humber

Annual Report Data

Year	Total In	Total Clinical	IBA Out	ACP Out	Op Hours
2019	13200	12940	2584	913	13760
2018	13937	13937	3137
2017	14111
2020	12754	12539	2358	807	15660
2021	10625	10280	2460	705	12246
2022	13198	13017	1921	799	14643

Knostrop Clinical Incinerator, SRCL, Captured from Google Earth June 21, all rights reserved

Summary

Clinical Waste Incinerator operated by SRCL and located adjacent to Knostrop Treatment Works, Leeds, of a twin-line stepped hearth design, with an annual throughput limit of 17,000 tonnes.

Plant

The Leeds incinerator consists of two streams, known as the East and West streams, each with a nominal throughput of one tonne of clinical waste per hour. The permit sets an annual throughput limit of 8,500 tonnes on each stream, with lower limits on specific waste types. The two streams are independent of each other, so that one stream can still be operated while the other stream is shut down for maintenance.

The two incinerators are of stepped hearth design, with three main combustion hearths and an ash box. Clinical Waste is loaded mechanically direct from the wheeled bins used to deliver the waste, onto the first hearth, and the combustion process commences. Hydraulic rams operate at intervals to push the waste along the first hearth, until it falls off the end onto the second hearth where the waste burns vigorously at a temperature of between 1000 and 1100 degrees Centigrade. The waste is then pushed from the second hearth onto the third hearth, where it burns out to produce an ash. This bottom ash is then pushed into an ash box, where the fixed carbon in the ash is further burned out. The retention time on the hearths is approximately 12 hours, with the bottom ash being retained in the ash box for up to 8 hours before being dropped into a skip. Ram movements are programmed in relation to the number of bins fed.

The flue gases from the Incineration process then pass through a secondary chamber, or afterburner, where any gaseous products of Combustion are burned out under oxygen rich conditions. This stage is designed to destroy any Carbon Monoxide, Volatile Organic Compounds, and dioxins and furans produced by the Combustion process.

The flue gases are then cooled by passing through a waste-heat boiler and economiser, before passing into the final, abatement section of the process. Powdered lime (Calcium Hydroxide) and powdered activated carbon are added to the flue gases entering the abatement process to remove acid gases, heavy metals and residual dioxins and furans before discharge to atmosphere from the stack. The flue gases being discharged from the stack are continuously monitored for Hydrogen Chloride, Sulphur Dioxide, Carbon Monoxide, Oxides of Nitrogen, particulate matter (dust), Volatile Organic Compounds, oxygen and moisture content.

The incineration process produces two residues; bottom ash and spent lime. The bottom ash is sent to a recycling transfer station for reprocessing, the bulk of the material ultimately ending up as a landfill cover material. The spent lime, which is the residue from the flue gas abatement process, went to a site in Leeds where it is used to neutralise acidic wastes.

Waste Tonnage, By Origin

The table shows a list of the Waste for the Permit CP3930XL, that has arrived into sites as reported to the Regulator and then publicised in their reported statistics. The Data used is from the most recent returns. The total reported tonnage arriving at the site was: t.

Where this tonnage exceeds that reported in year of the corresponding annual report, this may be due to the following reasons:

• Tonnage may have been received but not incinerated, i.e. the material is held pending incineration (the operator return to the EA reports as received whereas the annual report focuses on when the waste is incinerated.)
• Material may have been received into the site but treated in some other way than incineration.
• Material may have been received on the but transferred out of site for disposal/treatment at another site rather than incineration on the site.

EWC Code	Origin of Waste	Tonnes In