Sodium ferrate can be used for the detoxification of toxic waters of the Krasny Bor landfill. Toxic waters from three acidic maps in non-flowing mode, storm drains from different points of the landfill bypass ditch in non-flowing and flowing modes. 

Krasny Bor’s maps contain about 2 million tons of hazardous liquid industrial waste: oil and heavy metals, especially hazardous first-class waste such as mercury, cyanide, arsenic, and cadmium. The landfill is located in the basin of the Neva River, which flows into the Gulf of Finland.

The Krasny Bor’s ecological problem is of an international level for the countries of the Baltic region: Russia, Finland, and Estonia. Water samples taken in 2016 by Helsingin Sanomat show that very hazardous substances from the maps seep out and are found in the forest outside the landfill (polychlorinated biphenyls and cadmium). Sodium ferrate is able to effectively decontaminate landfill maps and stormwater runoff from the landfill bypass ditch.

Stormwater treatment of the Krasny Bor landfill on the model of a complex water treatment plant using sodium ferrate

Wastewater treatment process parameters:

  • doses of ferrate and coagulants
  • the reaction time of oxidation and sedimentation
  • filtration conditions
  • the flow rate of purified water

Storm water from the Krasny Bor landfill (light):

Sodium ferrate dose 9 mg/l + 10 mg aluminum oxychloride, reaction and precipitation time – 15 minutes, sorbent MS + AS, flow rate 0.4 l/min (24 l/h )

Storm sewer from building 115 (dark color):

Sodium ferrate dose 18 mg/l + 20 mg aluminum oxychloride, reaction and precipitation time – 15 minutes, sorbent MS + AS, flow rate 0.2 l/min (12 l/h )

Ferrate oxidation and precipitation filtration results of liquid toxic waste from the Krasny Bor landfill

Stormwater and after oxidation

The purification of industrial wastewater with sodium ferrate solution on stormwater and water of three acidic pads 59, 66, and 67 of the Krasny Bor landfill, St. Petersburg has been tested.

The MPC requirements for household wastewater were fulfilled on storm runoffs after oxidation with ferrate doses of 10-20 mg/l, on maps at 50-60 mg/l.

According to the 59th card, the decrease in total nitrogen from 480 to 48 mg / l, chlorides from 1500 to 520 mg/l, petroleum products from 0.43 to 0.05 mg / l; The pH increased from 4.0 to 9, and the water corresponds to the maximum permissible concentration for household wastewater.

In the water of 64 and 68 maps, the amount of Cd decreased by 2000 times, Pb – 100 times, i.e. up to the MPC requirements.

The results obtained showed the high efficiency of ferrate in the treatment of toxic wastewater.

Initial water 59, 66 and 67 acid maps

After oxidation of 60 mg/l ferrate

Filter cakes

After filtration through the Baltek sorbent