by Natalia Chernihovskaya, October 13, 2019
In the last three years waste incineration plants that RT-Invest is constructing in the Moscow Region have become a key topic in the media. There are serious concerns that these plants will cause major damage to people’s health and to the environment. These concerns have raised a wave of protest actions in the areas adjacent to the plants. Opinions have split. Some are certain that waste incineration is safe enough because this technology has been used in Europe for a long time. Others believe waste incineration plants are silent killers because exhaust from chimneys and incineration residue will contain a huge amount of dioxins which are highly poisonous and are more toxic than some warfare agents.
Hitachi Zosen Inova technology purchased by RT-Invest Moscow-based company is a waste-to-energy (W2E) technology of grate incineration. It was developed in the middle of the 20th century and until recently was widely used in Europe and Japan. Europeans were proud of their waste incineration plants and, being certain of their safety, placed them near settlements, villages and even in cities. It was believed that after restructuring of waste incineration industry conducted in the 70s-90s, waste incineration plants became totally safe for the people and environment. However, a few years back, some shocking facts came out and disproved that belief.
Since 1997 until 2007 Spanish experts collected medical statistics on cancer patients who lived near waste incineration plants in Spain. After the research over, the Spanish experts published an article with heavy arguments proving that 90 thousand people died from 33 forms of cancer in the ten year timespan. The article came out in 2013 and four years later EU environmental institutions strongly recommended to stop investments in new waste incineration plants and gradually replace waste incineration with other ways of waste treatment – thermal destruction, recycling and waste reuse.
In the meantime, $2 billion have already been spent on four Hitachi Zosen W2E plants. They will be constructed in Timohovo, Mogutovo, Svistyagino and Solnechnogorsk and will process 2,8 million tons of waste per year. That will be tailings left over recycling of all of 11 million tons of Moscow municipal waste. Accordingly, 8,2 million tons will be partly recycled and partly taken to landfills.
Construction of the first plant in Svistyagino is in full swing. It will be launched in 2021. However, it has already become obvious that, first, Hitachi W2E plants are a money pit, not only because of the original high cost, but also because of high maintenance costs; second, W2E plants will produce dangerous dioxin exhaust in the amount of 400 thousand square meters per hour and dioxin ash residue in the amount of 35% of one load. The exhaust and the residue will have to be treated too. The cost of treatment is not included in the cost of W2E plants. Moreover, Hitachi Zosen technology does not provide for exhaust control and ash residue treatment. Different parts of the technological chain need to be replaced every two years which will cost up to 40-50% of the basic W2E plant value. This explains high maintenance costs of W2E plants. Considering one plant costs $500 mln, replacement of parts will cost additional $200-250 mln. It turns out that the cost of waste fuel will exceed $1000 per one ton. Such rate will burn an enormous hole in the budget of Moscow and in the pockets of the citizens.
According to the original plan, ash residue was supposed to be taken by rail to the city of Tomsk, Western Siberia, where there are special enterprises technologically equipped for dangerous substances treatment. However, later it became clear that is not an option because on the way to Tomsk a vast territory will be exposed to dioxin contamination. Another thing is that Tomsk enterprises are not designed for such enormous amounts of toxic waste brought from Moscow W2E plants.
Once RT-Invest owners realized the scale of the catastrophic failure they were facing, they desperately started looking for the way out. And they lucked out – two Russian old school scientists Mr. Igor Mazurin and Mr. Sergey Ognyov – came to their aid.
It turns out that in the Soviet Union by the 70s there was a number of fully worked out waste treatment technologies, but they were majorly used for industrial purposes. By the early 90s with the transition to the market economy and total commercialization those technologies was neglected. Now that we found ourselves in the dead end of waste management crisis it’s high time to bring those technologies back to life.
Mr.Mazurin and Mr.Ognyov have similar backgrounds but in different industries. Now they decided to pool resources to “cure” W2E Hitachi plants purchased by RT-Invest. They found the remedy – the technology of electric arc melting and catalytic afterburning. Read on to learn what this technology is about.
After burning on the grate, three components are formed – ash residue, dust and smoke gases. All three are highly toxic and contain a huge amount of dioxins. That’s why they need to go through several stages of cleaning. The first stage implies capturing ash residue, dust and smoke and directing them into a special chamber for electric acr melting: carbon electrodes enter the chamber, electric current is supplied and an electric acr appears between the electrodes. The mixture begins to melt. Slowly the temperature rises to 1600-1800 degrees C and the melting mass turns into a liquid, so called melt. In the pyrolysis process, different gases are emitted – they have the temperature of 1300-1400 degrees C – and two liquid fractions are formed – pig iron and basalt melt. They sink through special holes to the bottom of the chamber. After gases are emitted, the chamber can be refilled, for example, with methane, necessary for formation of basalt melt which can later be used for production of expanded clay basalt used in construction.
Okay, let’s go back to emitted gases. After they leave the electric melting chamber, they go to a reactor where they pass through the second stage of cleaning, called oxidation: gases are mixed with a lime suspension (CaCO3) which leads to formation of air and finely dispersed dust – nitrogen and oxygen with particles of dust; in the meantime nitrogen oxides (NOx) end up being neutralized. The flow moves with the speed of 3 to 6 seconds. Sometimes it can take up to 8 seconds.
Later on the gas mixture cools down and passes the third and the forth stages of cleaning – wet and dry scrubbers. In the scrubbers, two types of the cleaning process happens – mechanical cleaning and water cleaning. After the scrubbers the mixture is fed into a sleeve filter where it is cleaned with a special fabric that catches particles of dust. After that, they get shaken off with an air flow. This is the fifth stage of cleaning. This dust looks like regular ashes, but it contains a huge amount of contaminants including dioxins. This dust is loaded back into the electric melting chamber and the whole process starts over with a new load of sludge. After the sleeve filter cleaned gases are not thrown out into the atmosphere. They are directed onto two catalytic processes. As a result, they get transformed into a liquid phase. Later they will be taken to different Russian plants where there is technology and equipment for treatment of poisonous biological and chemical agents. At the end of the procedure all contaminants are neutralized which makes waste incineration totally safe for the people and the environment.
Thus, Mr.Mazurin and Mr.Ognyov will be able to correct the mistake of the authorities with Hitachi Zosen plants, save lives and a lot of money. This tactical move will allow to eventually give up on waste incineration landfills and in the near future start using safe pyrolysis based technology for waste treatment completely excluding grate incineration.
That said, the scientists believe that recycling plants also need additional cleaning of emitted gases and other waste and the pyrolysis based technology can be used in this case too.
Now we can take a breath of relief. There’s a way out. All we need is to wait a little bit until our scientists test their technology within W2E Hitachi plants and launch it into work in the next two years.