NITROGEN REMOVAL IN POND SYSTEMS WITH DIFFERENT CONFIGURATIONS AND GEOMETRIES

Nitrogen removal in its various chemical forms was evaluated in a comp lex of waste stabilisation ponds comprising ponds of different depths and geometries. TKN and ammonia removal reached 78.5% and >90%, respec tively, ill the 5-pond systems with overall retention times of only 19 days. Removals were highest in the maturation ponds, and shallow matu ration ponds were the most efficient. In terms of optimum pond geometr y, high nitrogen and ammonia removal was compatible with optimal BOD5 removal and faecal coliform die-off. TKN and ammonia removal in these ponds could be modelled using conventional first-order equations.