THE EFFECTS OF NUTRIENTS ON NATURAL ORGANIC-MATTER (NOM) REMOVAL IN BIOLOGICAL ACTIVATED CARBON (BAC) FILTRATION

Effective biodegradation of organic compounds is one of the major obje ctives while optimizing biological drinking water treatment processes. Enhancing the biological activated carbon (BAC) filter performance wi th nutrient addition was studied using chemically pre-treated and ozon ated lake water. Three parallel pilot-scale biofilters were operated: one with phosphorus addition, one with a mixture of inorganic nutrient s addition, and one as a reference. The addition of nutrients had no s tatistically significant influence on the natural organic matter (NOM) removal when monitored by total organic carbon (TOC), UV absorbance, and assimilable organic carbon (AOC). However, the addition of nutrien ts significantly increased the heterotrophic plate count (HPC) bacteri a of the filter effluent, while the adenosine triphosphate (ATP) analy sis of the attached bacteria did not show any increase in BAC filters. It seemed that in BAC filters the bacterial growth was limited by pho sphorus, but the increased bacteria could not attach themselves during the relatively short acclimatization period.