World's largest membrane leachate-treatment plant handed over
Norit X-Flow and ISTAÇ (Istanbul Metropolitan Municipality Environmental Protection & Waste Materials Valuation Industry) celebrated the handover on 17 August 2010 of a notable wastewater treatment project: the treatment of leachate from the Istanbul landfill in Odayeri and Kömürcüoda.The installation has become the largest membrane leachate plant in the world and involves the most advanced water treatment technology available.
"The ISTAÇ Leachate Treatment project represents one of the most challenging filtration projects globally, based upon its size, environmental conditions and continuous growth rates," says Jürgen von Hollen, managing director of Norit X-Flow. "The solution had to be robust, future-proof and deliver consistently the highest effluent quality levels to ensure the environmental integrity of the region."
After approximately two years of operation and treating up to 3,500 m³ of landfill water percolate on a daily basis, the plant has met its specifications and contractual requirements for discharge of the treated effluent.
Water percolating through landfills for solid waste results in leachate, which may contain undesirable or toxic chemicals. The ISTAÇ landfill is constructed to prevent leachate contamination of groundwater or surface waters.
The landfill percolate, containing high amounts of chemical oxygen demand (COD), biochemical oxygen demand (BOD), total suspended solids and nitrogen, is collected and treated by Norit's membrane bioreactor (MBR) technology which makes it possible to discharge this water directly into the Black Sea, a process that is in line with both current and future drainage standards.
As well as MBR technology, the Istanbul plant uses a combination of two advanced Norit X-Flow technologies: a biological process applied in conjunction with ultrafiltration followed by nanofiltration (NF).
The collected leachate is first subjected to primary clarification and afterwards transferred to a bioreactor unit for biological treatment. In the bioreactor COD, BOD and nitrogen compounds are eliminated. Subsequently the Norit X-Flow crossflow membrane system, placed outside of the bioreactor, separates sludge, solid waste on suspension and some COD.
Lastly, the Norit NF installation eliminates the remaining COD, organic micro-polluters, heavy metals and other compounds (humic acids, color) to a water quality conform current and future discharge standards.