USING PH AS A REAL-TIME CONTROL PARAMETER FOR WASTE-WATER TREATMENT AND SLUDGE-DIGESTION PROCESSES

The alternating aerobic-anoxic (AAA) process offers many advantages fo r wastewater treatment and sludge digestion, Laboratory scale experime nts were conducted to investigate the feasibility of using pH as a rea ltime control parameter for this process, Several well defined control points on the pH curve were identified, e.g., ammonia valley and nitr ate apex, These points were directly related to the alternating nitrif ication and denitrification reactions in the process, and were found t o be consistent with those previously identified using ORP. Although b oth pH and ORP can be used as real-time control parameters, pH provide s several additional advantages over ORP. Based on these findings, rea l-time control strategies (fixed pH setpoints and dynamic pH control) were developed and tested. Results from laboratory scale AAA sludge di gestion using fixed pH setpoints (6-8) indicated that 36% MLVSS reduct ion, 39% TN reduction and almost 48% saving in aeration energy was ach ieved after 300 hrs of digestion.