Incineration technology

Waste is transported to the site in special containers and barrels placed in enclosed transport vehicles, or in tank truck. Solid wastes are emptied into the  solid waste bunkers, or are collected in closed containers on  the reception area.

Healthcare wastes are transported in hermetically sealed (ADR certified) plastic containers equipped with a special, single-use, insoluble bond in closed transport vehicles. The  containers are transferred  to the feed chute of a rotary kiln  without being touched by human, and then through a double sluice into the furnace.

Paste-like waste and any other type of waste arriving in barrels, separated by their inflammability class, is collected in covered, chemically resistant, andesite-bottomed barrel-storage equipped with a retention pit.

Liquid wastes are mixed based on their  calorific value, blending and chemical properties, and are collected in conical bottomed, cylindrical, rigid-topped steel storage tanks equipped with a stirrer and placed in retention pits.

A part of the waste consisting of mixed consistency materials is pre-treated before being fed into the rotary kiln.

The shredding of solid and paste-like wastes is carried out by a hydraulic shredder installed in the waste reception building. The shredded waste  is loaded into a feeding system by a mechanical grabber  crane and then dosed to the rotary kiln. „A” and „B” class shredded and homogenized solid wastes are fed into the kiln from a separate bunker (bunker 4).

Incineration is planned on the basis of an optimization program, which allows us to determine the hourly waste streams of the various  composite wastes, taking into account the heat load of the furnace.

Thermal treatment

In order to ensure the safe and perfect combustion of waste that contain more than 1 % halogen, the temperature of the afterburning chamber must be at least 1100 oC after the final combustion air has been admixed. The incineration is carried out in a rotary kiln with refractory lining at 1250 +/- 50 oC. The thermal treatment of persistent substances is carried out in an afterburning chamber. Afterburning is optimized by the introduction of secondary air, which provides the right temperature and oxygen concentration. Temperature in the afterburning chamber is 1150 +/- 50 oC, the flue gas residence time is at least 2 seconds.

Flue gas from the afterburner enters the heat recovery boiler where the recovered heat is used to produce steam. The steam exceeding the demand of our plant is sold.

Flue gas cleaning

The first step of the flue gas cleaning system is the hydrated lime absorber, which partly absorbed the acidic components. Dioxins and furans and other polluting compounds are adsorbed in the reactor by active carbon. This process is enhanced by slowing down the speed of the flue gas, and increasing the residence time.

Pre-treated flue gas loses its dust content in the bagfilter. Built in between the bagfilter and the scrubber, the dioxin catalyst as well as the  extraction fan provides constant depression in the combustion chamber and the flue gas cleaning system. The catalyst used for dioxin removal is vanadium pentoxide applied to sponge-like titanium dioxide, which helps the decomposition of dioxin and furan by oxidation.

The final stage of the flue gas cleaning system is the counter-current scrubber equipped with two-plane spray nozzles. Triggered by the hydrated lime, the washing liquid in the washing tower cools down to the saturation temperature of the water vapour and becomes saturated with water vapour, thus absorbing the remaining pollutant. Gypsum sludge formed at the bottom of the washing-tower is deposited in the conical part, then drained with vacuum drum filter and collected in steel containers and then recycled into the rotary kiln. Purified flue gases are rejected to the outside air through a 70-m chimney.

Flue gas monitoring and control

The composition of the flue gas is continually checked and registered according to European Union regulations. These measurements form an integral part of the supervisory system. Substances used or produced during the technological processes are continuously analysed by our laboratory.

Physico-chemical treatment process

The physico-chemical pre-treatment system aims to clean contaminated water containing various hazardous waste from inorganic and organic pollutants. The small amounts of pollutants produced after the treatment is treated by incineration, and then the cleaned water is further treated in an industrial waste water treatment system.