Estimating the effect of VPK-402 flocculant-coagulant on the sorption properties of powdered activated carbon in the process of water treatment

Summary

The results of laboratory tests on estimating the effect of VPK-402 organic flocculant-coagulant on the sorption capacity of powdered activated carbon in relation to phenol in the process of natural water treatment using the technologies adopted by the water utilities are presented. The results showed that the effect on the sorption efficiency depended not so much on the point of VPK-402 injection – upstream or downstream the point of powdered activated carbon injection, as on the time of it contacting with water containing phenol. The minimum decrease of the purification efficiency of 3.2–4.5% was observed upon 60-minute contact with powdered activated carbon, regardless of the injection of the flocculant – before or after the injection of the sorbent. With a short contact with powdered activated carbon (2 minutes), a decrease in the efficiency of removing phenol by 7.8–16% was observed compared to blank tests without the use of a flocculant.

Key words

natural water treatment , powdered activated carbon , flocculant-coagulant , dephenolizing

Estimation of possible increasing the barrier function of natural water treatment facilities during periods of extraordinary situations

Summary

The need of increasing the barrier functions of water treatment process schemes and facilities during the periods of extraordinary pollution of water bodies is considered. The causes of extraordinary situations at water sources are as follows: industrial and transport accidents, manmade disasters, seasonal floods and even waterless seasons. The differences between extraordinary situations and their consequences in the water treatment practice from ordinary cases are given. Rules have been developed for preparing clean water of standard quality in emergency situations. Laboratory tests of water purification from the sources of various climatic zones using powdered activated carbons were conducted with water from Yakutsk, Astrakhan, Ryazan and Simferopol water utilities. The main sorption characteristics of the tested sorbents for methylene blue and iodine were determined. The results of testing powdered sorbents for four water sources showed that, compared with the traditional two-stage water purification scheme, the use of powdered activated carbon in the headworks of the process flow scheme provided for achieving the standard values for the permanganate index and total iron concentration. Also, unpleasant odors of water are almost completely eliminated, while no increase in coagulant doses was required compared to the operating facilities. It is shown that the efficiency of using powdered carbon practically does not depend on the climatic conditions of the regions. A generalized chart for the use of powdered carbon at the facilities with a two-stage treatment process flow scheme is proposed.

Key words

water treatment , natural water treatment , laboratory tests , extraordinary situations , powdered activated carbon