Kemira Oyj

Bengt Hansen

Sakari Halttunen

Outi Grönfors

Joonas Likander

Fazlollah Azarnoush

Hanna-Mari Kangaslahti

The present invention relates to a process for treating primary sludge in a wastewater treatment plant, comprising the steps of admixing an organic coagulant and/or polymer to wastewater; allowing a primary treatment of the wastewater in the presence of the organic coagulant or polymer; separating solids as a primary sludge from said primary treatment; and dewatering the primary sludge. The present invention further relates to a method of improving primary sludge dewaterability and improving energy balance of a wastewater treatment plant.

Improving sludge dewaterability and energy balance of wastewater treatment

The present invention concerns a process for recovering phosphates from wastewater by adding to the wastewater at least one organic coagulant or polymer in a mechanical treatment step that leaves dissolved phosphorus in the water phase, separating a mechanical sludge from the treated wastewater, preferably by sedimentation, flotation or filtration, carrying the phosphorus-containing treated wastewater in a post-treatment step, where at least one chemical precipitant is added to precipitate the dissolved phosphate into solid phosphates, and separating the solid phosphates from the treated wastewater to recover the phosphates.

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Ramlösa, Sweden

Bengt Hansen