METHOD FOR TREATMENT OF SEWAGE SEDIMENTS WITH REMOVAL OF HEAVY METALS (VERSIONS) Russian patent published in 1996 - IPC

FIELD: methods for treatment of sewage sediments with removal of heavy metals. SUBSTANCE: method for treatment of sewage sediments with removal of heavy metals includes washing of initial sediments, separation by compaction into sewage and compacted sediment; treatment of sediment with acid; separation into solid phase and liquid phase containing heavy metal ions; mixing of liquid phase with neutralizing agent and subsequency separation of mixture into sludge containing heavy metals and clarified liquid phase. Sewage water is used as neutralizing agent. method includes anaerobic fermentation of initial sediments, washing of fermented sediments with water, separation by compaction into sewage and compacted sediment, acid treatment of sediment is conducted in two stages. At the first stage, compacted sediment is mixed with wash water and acid with subsequent separation of acid sewage from compacted acid sediment which is aerated in the second stage in the presence of acidofil microorganisms and/or mixed with acid and oxidizer. Then, treated sediment is separated into solid phase and liquid phase containing ions of heavy metals. Liquid phase is mixed with neutralizing agent with subsequent separation of mixture into sludge containing heavy metals and clarified liquid phase. During mixing of liquid phase with neutralizing agent, acid sewage is introduced. EFFECT: reduced consumption of alkali reagents and consumption of acid reagents, increased rate of removal of heavy metals from solid and liquid, phases, decreased load on treatment facilities in terms of suspended matter and ammonium nitrogen. 8 cl, 2 dwg