EUROPEAN OPERATING EXPERIENCE WITH A HIGH RATE PROCESS FOR NITROGEN CONTROL

Abstract SHARON ® is a very cost-effective treatment system for the total removal of nitrogen components, thru nitrification/denitrification, from wastewater flow streams containing high concentrations of nitrogen. The system is used in the treatment of municipal wastewater side streams from both dewatered digested primary sludge and waste activated biosolids to achieve high total overall nitrogen removal. It is also used for the treatment concentrate from sludge and biosolids drying facilities, of high strength land fill leachate, and manure treatment wastewaters.SHARON ® is a high rate process for the removal of total nitrogen operating with minimal sludge retention time. Due to differences in growth rates of the bacterial species at the process design temperature (30-40 °C) a selection can be made wherein the nitrite oxidizing bacteria can be washed out of the system while ammonia oxidizing bacteria are retained along with denitrifying bacteria. Using this metabolic mode of operation allows for a 25% reduction in aeration energy required for nitrification and a 40% reduction in the amount of BOD addition needed for denitrification. In addition since the process is accomplished in a side stream there are savings in mainstream reactor costs.The pertinent principles of both nitrification and denitrification and also the SHARON ® process design parameters are developed. Three full-scale SHARON ® systems have been constructed at large wastewater treatment plants in Europe and a fourth is under design. The results of the full scale operation at the Rotterdam, Dokaven Plant, Netherlands, are presented. The Utrecht Plant is illustrated.