Compte rendu en anglais de la visite d'AVR
Visit of the AVR plant – Rotterdam – 17 May 2016
(1e S - DNL Physique-Chimie)
On Wednesday 17th of May, the 11th grade class of DNL Physics was lucky enough to visit the AVR waste to energy plant just outside of Den Haag, thanks to their teachers, M. Eneau and Mrs. Mangenot.
Converting waste into energy
This plant converts waste into steam, heat, and electricity thus powering hundreds of thousands of houses and businesses with heating and electricity.
The plant runs on any kind of waste from fruits, vegetables, garden waste, plastic, waste wood, and paper bags to trash bags full of domestic from local homes and businesses all while being as green and efficient as possible. These AVR plants are so efficient (having burned in 2014 around 1.8 million tons of Dutch waste) that they even burn waste from countries that do not have the necessary infrastructures to convert their waste into energy (AVR has processed about 0.4 million tons of waste from other countries in Europe – such as Italy, the U.K. or Ireland…) through burning.
From waste to ashes
To understand how AVR manages to efficiently create energy from waste we must first analyze the waste’s trip from public garbage to clean energy. It all begins with the waste coming into the plant. It either comes in by truck, which represents a bit less than 1/5th of the total deposited waste or by boat through the back of the plant on a network of canals. This waste is then dropped off into a huge 14-meter deep pit or bunker. At this stage, cranes inside the bunker pick up the waste and sift through it to separate it and take out as much humidity and liquids as possible. These cranes then drop the picked-up waste into enormous incinerators heated to about 1,000 degrees Celsius.
Recycling ashes
After a while the waste turns to ash and falls to the bottom of the incinerator. Due to the slope at the bottom of the incinerators and the huge gears that help churn out what’s left of the waste the ashes drop out of the incinerators onto a conveyor belt. The conveyor belt wraps around the plant. When on this conveyor belt, the ashes are soaked in water to drop their temperature to a cool 80 degrees Celsius. The ashes are then deposited outside where the company can start its sorting job. AVR uses many techniques refined over the years to extract as much useful material from the ashes such as metals (for which they use a complicated set of magnets). They then sell these metals as raw materials back to the metallurgical industry. Most of the rest is sold to companies that make highways to be used as base substrate for their roads. Only a tiny percentage is left over that cannot be recycled or reused (yet!), this remainder is packed up and kept in a storage hangar until AVR figures out a use for it.
Producing energy
While selling ashes and metals to companies remains one of the pillars of AVR’s income, their main priority is still converting waste to energy. While the ashes are being sifted through in search for anything of use the heat created by the incinerators heats up water to make steam.
This steam is then pushed through hundreds of meters of sealed tubing to power a number of generators that thus create electricity which is then distributed to households near the plant.
The steam is then pushed again into kilometers of pipes to be sold to different companies.
Pollution treatment
That is all well and good, but some might be wondering what happens to the fumes from the incinerators, the one used to heat up the water in the first place? It can’t be non-polluting right? That would indeed be right; the fumes coming out of the incinerators are indeed toxic and dangerous as they carry unhealthy chemicals and “fly ash”. Fly ashes are ashes that were too light too be swept with the rest of the ashes but instead float up with the fumes. These are especially dangerous because they can easily be sucked into a person’s lungs and can cause irreparable damage. This is why a big chunk of AVR’s plants are made up of treatment centers for the steam. The fumes that exit the incinerators are led through a series of tubing to be treated for their different chemicals and particles so that at the end, no harmful gases escape into the atmosphere.
To conclude, this is how AVR manages to be a “green”, cost and power efficient plant that reduces a country waste while churning out a sizable profit. It is the perfect example of a win-win situation, we get rid of our waste and get heating and power while AVR gets to burn it and resell it. Who knows maybe one day this will become most countries-main source of electricity and waste disposal.
Constantin and Roxanne, 1e S DNL
Special thanks go to M. Lukacie from AVR who organized this visit for our group !
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