Laadi alla infomaterjal

Viis aastat kestnud Kohtla-Järve tööstusjäätmete ja poolkoksi prügila sulgemistööde raames teisaldati 6 miljonit m³ mäemassiivi, paigaldati enam kui 8 km pikkune sademevee kogumise süsteem ning suleti ca 2,5 ha suurused fuussijärved. Väga järsu kaldenurga all teostatud töid (kõige järsum osa objektist nõlvusega ehk nõlva kõrguse ja laiuse suhtega oli 1:1) muutsid veelgi keerulisemaks 2013. aasta algul avastatud põlengud. Põlengu summutamiseks ja õhu juurdepääsu takistamiseks kaeti kolded üle 2 meetri paksuse vana tuha ja vähese orgaanika sisaldusega ja halva soojusjuhtivusega poolkoksi isolatsioonikihiga. Vaatamata õhu juurdepääsu sulgemisele, põleng koheselt ei kustu, kuid põlenguprotsessid aeglustuvad, mistõttu sisaldas põlenguala kattekonstruktsioon ka gaaside kogumise ja väljutamise kihti, mis rajati paekivi killustikust

fraktsiooniga 32..64 mm. Üle 0,5 m paksune gaasikogumiskiht jäeti gaaside väljumiseks põlenguala ühelt küljelt avatuks. Prügila katmisel anti ladestule kõigepealt planeeritud kuju ning pealispind tihendati ja tasandati. Tagamaks nõudeid suletud ladestu kattekihi veejuhtivusele, kaeti ladestu bentoniitmattidega. Vettpidavale mineraalkihile veesurve alandamiseks ja läbi kattekihi filtreerunud sademevee ära juhtimiseks kasutati drenaažimatti, mis paigaldati otse bentoniitmatile. Nõlvadel, mille nõlvus on ≥ 1:2, kasutati kattekihi stabiilsuse tagamiseks lisaks geovõrku, mis paigaldati bentoniit- ja drenaažimattide peale. Kattekihina kasutati värsket poolkoksi. Hüdrokülvi tehti objektil kokku umbes 60 hektaril, arukaskedest metsa istutati koos aluse hüdrokülviga kokku ligikaudu 24 hektaril.

Tööstusjäätmete ja poolkoksi prügilate sulgemine Kohtla-Järvel

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Kohtla-Järve, Ida-Virumaa Keskkonnaministeerium prügilate sulgemine 2009-2014

A hill of mine waste amounting to 6 million m³ was relocated, 84 hectares were replanted, a rainwater collection system more than 8 km long was installed, and 2.5 hectare lakes containing liquid oil shale mining residues were closed – all part of the operation to close the Kohtla-Järve industrial waste and semi-coke dump in north-eastern Estonia. The works, undertaken on a very steep slope, were rendered even more complicated by smouldering fires discovered in early 2013, which were buried up to 5 metres deep. To extinguish the blaze and prevent air from reaching it, the burning areas were covered with a 2-metre-thick layer of old ash and an insulation layer composed of semi-coke with low organic content and heat conductivity. In spite of cutting off the access of air, the blaze did not go out right away, but the combustion processes slowed down, as a result of which the covering structure of the blaze area also contained a gas collection and removal layer that in turn was made up of a crushed limestone with particle size of 32-64 mm. This layer, which was over 0.5 metre thick, was left open on one side to allow gases to exit the blaze area. In the course of covering over the dump, the area was first given its new shape specified in plans, and then the surface was compacted and levelled. To ensure that water could run along the top layer of the closed dump, it was covered with bentonite mats. To reduce the water pressure on the waterproof mineral layer and divert any run-off that filtered through the covering layer, drainage mats were used, being installed directly on the bentonite mat. On slopes at an angle of 1:2, a geo-mesh was used in addition to ensure stability of the covering layer. The geo-mesh was installed on top of the bentonite and drainage mats. Fresh semi-coke was used as the covering layer. The hydro-sowing was performed over a total of about 60 hectares, and a total of about 24 hectares were planted with silver birches using hydro-sowing.

Closing of industrial waste and semi-coke landfill in Kohtla-Järve

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Kohtla-Järve, Ida-Virumaa Estonian Ministry of the Environment closing the waste landfill 2009-2014