IMPROVEMENT OF POLUTANT REMOVAL FROM WASTE WATERS OF METAL TRETMENT INDUSTRY

Procesi površinske obdelave kovin povzročajo nastajanje odpadnih industrijskih voda, ki se pred izpustom v vodotok čistijo v fizikalno–kemijski čistilni napravi. Namen naloge je bil s pomočjo deemulgatorjev razbiti in ločiti emulgirana olja v odpadni vodi, nato pa poiskati učinkovito kombinacijo koagulanta in polielektrolita, ki bi lahko zamenjala železov klorid (Feriklar) in polielektrolit (Praestol 2500), ki ju sedaj uporabljajo pri čiščenju industrijske odpadne vode. Z Jar testi smo simulirali delovanje čistilne naprave oz. postopke koagulacije in flokulacije. Učinkovitost koagulantov smo določili z analiznimi postopki, ki zajemajo koncentracijo niklja in celotnega fosforja, kemijsko potrebo po kisiku, količino mulja ter koncentracijo mineralnih olj v prečiščeni vodi. Raziskave so pokazale, da med vsemi preizkušenimi koagulanti ni bilo bolj učinkovitega od obstoječega Feriklara, saj smo z laboratorijskimi testi dokazali, da s pravilnim doziranjem Feriklara znižamo koncentracijo vseh navedenih parametrov, tudi količino mineralnih olj. Med flokulanti sta bila P3-8723 in Optimer 9901 bolj učinkovita kot Praestol 2500. S kombinacijami koagulantov in deemulgatorjev sicer nismo dosegli izboljšanja kvalitete odpadne vode, ker so preizkušeni deemulgatorji motili proces koagulacije in flokulacije. Določili pa smo natančnejše doziranje Feriklara in nova učinkovitejša polielektrolita, kar je bila osnova za prenos laboratorijsko določenih parametrov v delovanje fizikalno-kemijske čistilne naprave.Processes of surface treatment of metals induce the occurrence of industrial waste water discharges, which are physic-chemically treated in the waste water treatment plant. The purpose of diploma was to decompose and separate by means of oil de-emulgators the emulgated oils in the waste water and then to find efficient combination of coagulant and polyelectrolyte, which could replace the Iron chloride (Feriklar) and polyelectrolyte (Praestol 2500), used nowadays in purifying industrial waste waters. The operation of the waste water treatment plant and the procedures of coagulation and flocculation were simulated using Jar tests. Efficiency of coagulants were defined with analytical procedures, including the concentration of nickel and total phosphorus, chemical oxygen demand, quantity of sludge and concentration of mineral oils in the purified water. Research showed that none of all tested coagulants was being more efficient than the existing Feriklar. Laboratory tests showed that correctly dosed Feriklar ables the reduction of concentration of all indicated parameters, as well as the quantity of mineral oils. Among flocculants P3-8723 and Optimer 9901 were more efficient than Praestol 2500. By combining coagulants and de-emulgators we have not obtained quality improvement of waste waters because tested de-emulgators did not improve the process of coagulation and flocculation. However, we have established more precise dosing of Feriklar and of a new, more effective polyelectrolyte, which was the base to adopt laboratory defined parameters to the waste water treatment plant