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==Summary== | ==Summary== | ||
[[Clinical Waste Incinerator]] operated by [[SRCL]] and located in Avonmouth, with an annual capacity limit of 6,570 tonnes. | [[Clinical Waste Incinerator]] operated by Stericycle ([[SRCL]]) and located in Avonmouth, Bristol. It is designed to process 750 kilgrams per hour<ref name="SRCL">Operator's Annual Report 2020</ref> with an annual capacity limit of 6,570 tonnes. | ||
The Avonmouth plant [[incineration|incinerates]] [[Clinical Waste|clinical waste]], including [[clinical Waste|clinical wastes]] classed as hazardous under the [[Hazardous Waste (England and Wales) Regulations 2005]]. The bulk of the [[Clinical Waste|waste]] is produced at hospitals, but also includes smaller quantities from doctors’ surgeries, dentists, health clinics, residential and nursing homes, and from medical research facilities. The [[Hazardous Waste|hazardous wastes]] [[Incineration|incinerated]] include infectious waste and [[Clinical Waste|waste]] containing cytotoxic or cytostatic medicines<ref name="SRCL" />. | |||
The plant also [[Incineration|incinerates]] small amounts of specialised wastes where it is recognised that [[High Temperature and Clinical Waste Incineration|high temperature incineration]] represents the best [[Disposal|disposal]] option<ref name="SRCL" />. | |||
==Plant<ref name="Adden">Annual Performance Report 2020</ref>== | ==Plant<ref name="Adden">Annual Performance Report 2020</ref>== | ||
The [[Avonmouth Clinical Waste Incinerator]] is of stepped hearth design, with three main combustion hearths and an ash box. [[Healthcare Waste|Healthcare wastes]] are loaded mechanically direct from the wheeled bins used to deliver the [[clinical Waste|waste]], into the inspection cradle which provides the opportunity to visually inspect the [[Clinical Waste|waste]] before it is tipped into the [[incineration|incinerator]] charging hopper. | |||
The [[Clinical Waste|waste]] is discharged into the loading box and is pushed from there onto the first hearth where the [[combustion|combustion]] process commences. Hydraulic rams operate at intervals to push the [[Clinical Waste|waste]] along the first hearth, until it falls off the end onto the second hearth where it burns vigorously at a temperature of between 850°C and 1000°C, where it burns out to produce an ash. This [[Incinerator Bottom Ash|bottom ash]] and any remaining part-combusted [[Clinical Waste|waste]] is then pushed onto the last hearths, where the fixed carbon in the ash is further burned out. The retention time of the entire process is between 4-6 hours. The residues are then dropped into an ash quench pit at the end of the process before being transferred into a skip. Ram movements are programmed in relation to the number of bins fed. | |||
The [[Flue Gas|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 [[Wikipedia:Carbon monoxide|Carbon Monoxide]], [[Wikipedia:Volatile organic compound|Volatile Organic Compounds]], and [[Wikipedia:Dioxins and dioxin-like compounds|dioxins]] and [[Wikipedia:Furan|furans]] produced by the [[Combustion]] process. [[Wikipedia:Ammonia|Ammonia]] in the form of [[Wikipedia:Urea|urea]] solution is injected into the secondary chamber for further control and reduction of [[Wikipedia:Nitrogen oxide|oxides of nitrogen]] emissions. | |||
The [[Flue Gas|flue gases]] are then cooled by passing through a waste-heat boiler and [[wikipedia:Economizer| economiser]], before passing into the final, abatement section of the process. Powdered [[Wikipedia:Lime (material)|lime]] (Calcium Hydroxide) and powdered [[wikipedia:Activated carbon|activated carbon]] are added to the flue gases entering the abatement process to remove acid gases, heavy metals and residual [[Wikipedia:Dioxins and dioxin-like compounds|dioxins]] and [[Wikipedia:Furan|furans]] before discharge to atmosphere from the stack. The flue gases being discharged from the stack are continuously monitored for [[wikipedia:Hydrogen chloride|Hydrogen Chloride]], [[wikipedia:Sulfur dioxide|Sulphur Dioxide]], [[Wikipedia:Carbon monoxide|Carbon Monoxide]], [[Wikipedia:Nitrogen oxide|Oxides of Nitrogen]], particulate matter (dust), [[Wikipedia:Volatile organic compound|Volatile Organic Compounds]], [[Wikipedia:Oxygen|oxygen]], [[Wikipedia:Ammonia|Ammonia]] and [[Wikipedia:Nitrous oxide|nitrous oxide]]. | |||
The [[Incineration|incineration]] process produces two residues; [[IBA|bottom ash]] and [[APC Residues|spent lime]]. | |||
==References== | ==References== |