LAURENIU TATARU, VALENTIN NEDEFF, NARCIS BARSAN, EMILIAN MOSNEGUTU, MIRELA PANAINTE LEHADUS, ION SANDU, DANA CHITIMUS STUDIES OF HUMIC ACID REMOVAL FROM AQUEOUS SYSTEMS BY USING POLYMERIC MEMBRANE ULTRAFILTRATION PROCESS This paper proposes to investigate in detail the behavior of polymeric membranes ultrafiltration process uses in the retention of humic acid from aqueous systems. Nowadays, the aqueous systems (contaminated water and/or wastewater) resulting from various domestic and industrial activities contain many contaminants, some of them increasingly dangerous to the environment. Laboratory testing of membranes in the ultrafiltration process as well as their experimentation with different chemical compounds is essential because it is important to know how they can be eliminated before they cause a negative impact. Testing of polymeric membranes consists in carrying out the process of ultrafiltration of aqueous systems containing humic acid over a set time, following the variation in time of the volume of permeate obtained as well as the influence of process parameters. Following the investigation of the ultrafiltration process of the water through the polymeric membrane, it was found that the formation of the humic acid layer on the surface of the membrane that favors fouling is delayed, after many hours of operation, due to both the internal fiber structure which offers advantages to this type of membranes as well as high efficiency of humic acid retention. Experimental results showed that the humic acid retention rate increased by up to 37% as a result of the double decrease of the conductivity value in the permeate samples from about 600 mS/cm to 373 mS/cm and the temperature being continuously increasing, from 22.5 at 25oC over 5 h influenced the entire ultrafiltration process. The full process approach as well as the expression and interpretation of the results will be detailed in this paper.