PVA(Polyvinyl alcohol) gel is a porous hydrogel that is ideally suited for immobilization of microorganisms essential for the degradation of environment pollutants.

The diagram shows BOD removal using PVS gel:

Example shows an existing wastewater plant which has 250m3 activated sludge tank and a 45m3 clarifier. The plant was first designed to treat 150m3/d with an influent BOD’s 1,000mg/L. Now the plant needs to upgrade to treat 300m3/d with same BOD, for which three designs options are shown. A conventional activated sludge system would require about twice the existing tank volume to treat the increased load.

Advantages: –

  • PVA gel is 4mm spherical beads having specific gravity of 1.025 ± 0.01 and thus excellent fluidity in water requiring minimal energy for mixing.
  • PVA gel treatment yields less excess sludge as compared to conventional biological methods.
  • PVA gel has very high water content due to its extensive porosity, thus allowing for favorable permeability of oxygen and nutrients to the bacteria colonized inside the bead.
  • Polymerized PVA gel is essentially insoluble in water and is not known to be biodegradable.
  • Depending on the characteristics of the wastewater, treatment ability using PVA gel can be enhanced up to 5 times that of conventional activated sludge, thus allowing for upgrading of existing overloaded system or for design of new process units with greatly reduced foot prints.
  • PVA gel can also be used for nitrification and denitrification as well as treatment of various industrial pollutants.
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