Agricultural reuse of the secondary effluent polished by an algal pond system coupled with constructed wetland.

In this paper, reuse potentials of the secondary effluents as irrigation water was evaluated through field sampling trips. Water quality parameters significantly deviating from its guidelines were Total coliform bacteria and organic matter. Even though nutrients are not regulated in Korea, their removal would be required because they have been a barrier for secondary effluent irrigation through governmental intervention. The results of treatment study with aquatic ponds show that in spite of its poor biodegradability, organic matter in soluble form was reduced by 20% during 10 days of HRT. On the other hand, reduction of nutrients was remarkable. On average 85% of total nitrogen and 89% of total phosphorus were removed, respectively, which abates the worries of farmers for overgrowth or reduction in crop yield. However, coliform bacteria, although slightly reduced due to their propagation at the constructed wetlands still need further treatment.