Whether it be household rubbish, construction rubble, contaminated soils, port sludge or waste incineration ash, final storage of these heavily contaminated materials poses a potential groundwater pollution risk from heavy metals, nitrogen bonds or organic substances. Landfill leachate resulting from precipitation on landfill sites.
Treating this seepage water is a challenge for distillation system technology. The solution: Our modular VACUDEST vacuum distillation systems. Its building kit principle allows individual adjustment to the particular requirements for treating landfill seepage water. For example, high-quality materials which reliably prevent corrosion, are used for heat exchangers, vacuum pumps and piping systems. This modern wastewater treatment technology also uses patented innovations to ensure discharge limit values which are reliably and in a cost-effective manner for the treated water.
Read here how satisfied waste management consortium Betearte is with VACUDEST’s treatment of its landfill leachate.
“A good feeling to know we have reliably met all required limit values”
In the Spanish town of Mallabia (Basque Country), waste management consortium Betearte – an association of the country’s three largest waste management companys – has started up a state-of-the-art landfill leachate treatment plant. The plant handles the entire, two-million-tonne landfill site, which is used as the final disposal site for industrial waste. Spanish company SIDASA, which chose the process for its cost-effectiveness and reliability, has been contracted to build and design the treatment plant.
The leachate is first temporarily stored in a 5,000-m³ tank to even out fluctuations in the precipitation volumes, and enable it to be continuously fed into the treatment system. Physical chemical pre-treatment of the process water is the first stage. The pollution load in the leachate is initially reduced with classic precipitation and flocculation, but the required limit values cannot be upheld by this process alone, as there are still too many neutral salts, heavy metals, nitrogen bonds and organic components in the clarification phase.
Facility picture Leachate treatment centres around the VACUDEST system.
Safe and reliable contaminant separation
The treatment therefore centres around the two VACUDEST distillation systems. It is this process which ensures reliable, safe separation of all contaminants. Each of the installed VACUDEST L systems has an annual capacity of 6,000 m³ per year, meaning a total of 12,000 m³ leachate can be treated. The entire process is automated, ensuring easy operation.
Treating leachate by distillation poses a challenge to system engineering. As a manufacturer of evaporator systems, H2O GmbH has therefore specially adapted serial products to leachate usage. For example, optimised materials are employed for heat exchangers, vacuum pumps and piping systems in order to prevent corrosion, even with high chloride loads. Heat exchanger surfaces in the VACUDEST system are kept clean during operation thanks to Activepowerclean self-cleaning so as to avoid mineral salts forming deposits. The resulting constantly clean heat exchanger guarantees a low energy consumption of just 50 Wh/l with a high evaporation rate.
“VACUDEST is the perfect evaporator solution for our landfill seepage water treatment,” says Ovidio Movellan from SIDASA. “We chose this system because the self-cleaning heat exchanger not only saves energy, but also large amounts of chemicals and cleaning time.”
Expectations well exceeded
Practice has proven that the leachate’s evaporation rate well exceeds expectations by a factor of 30. The quality of the purified water is so good that it can even be fed directly into the nearby river. Other waste management companies, such as Befesa in Spain or Veolia in France, have thus also chosen this evaporator technology.
“There is a wide variety of process combinations for treating seepage water – ion exchangers, membrane systems and biological processes are commonly used. But only the combination with vacuum distillation allows us to be totally sure when it comes to direct discharge. It’s a good feeling to know we have reliably met all required limit values,” Ovidio Movellan adds.
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