Optimum aerobic volume control based on continuous in-line oxygen uptake monitoring

Abstract

Dynamic adaptation of the aerated volume to changing load conditions is essential to maximise the nitrogen removal performance and to minimise energy consumption. A control strategy is presented which provides optimum aerobic volume control (OAV-control concept) based on continuous in-line oxygen uptake monitoring. For ammonium concentrations below 1 mg/l the oxygen uptake rate shows a strong and almost linear dependency on the ammonium concentration. Therefore, the oxygen uptake rate is an ideal indicator for the nitrification performance in activated sludge systems. The OAV-control concept provides dynamic variation of the minimum aerobic volume required for complete nitrification and therefore maximises the denitrification performance. In-line oxygen uptake monitoring is carried out by controlling the oxygen concentration in a continuous aerated zone of the aeration tank and measuring the total air flow to the aeration tank. The total air flow to the aeration tank is directly proportional to the current oxygen uptake rate and can therefore be used as an indicator for the required aerobic volume. The instrumentation requirements for installation of the OAV-control are relatively low, oxygen sensors in the aeration tank and an on-line air flow measurement are needed. This enables individual control of aeration tanks operated in parallel at low investment costs. The OAV-control concept is installed at the WWTP Linz-Asten (1 Mio PE) and shows very good results. Full scale results are presented.

Ammonia‐based intermittent aeration control optimized for efficient nitrogen removal

“…In fact, we also demonstrated that managing aerobic and anoxic volumes dynamically to deal with non-steady influent results in an optimum N removal. One such example is the optimum aerobic volume control concept (OAV-control concept), which is a control strategy that is capable of adjusting the aerobic and anoxic volume required for complete nitrification and subsequent maximization of denitrification (Svardal et al, 2003). It uses the measured airflow rate and DO concentration to change the aerobic volume to the NH 4 þ -N load.…”

Simultaneous Biological Nutrient Removal: A State‐of‐the‐Art Review

“…Oxygen control was recognized and implemented to achieve SBNR in the earliest observed instances, as identified previously, and was determined to be a critical parameter by numerous researchers such as Holman and Wareham (2005), Münch et al (1996), Pochna and Keller (1999), and Zhao et al (1999). The role of controlled aeration has been incorporated to full-scale plant process control strategies, as, for example, illustrated by Svardal et al (2003). Sufficient oxygen is provided so that nitrification can occur, but is restricted so that the nitrate formed must be used to stabilize some of the influent biodegradable organic matter.…”

Reclamation of textile dyeing wastewater for process use via a highly efficient integration system

“…The packing rate of SAC in the BAC reactor was controlled at 60%. By applying the oxygen uptake rate method [5] and a laboratory-scale biodegradation test (data not shown), effective microorganisms were deliberately screened from different kinds of activated sludge sources such as petrochemical sludge, textile dyeing sludge and industrial food sludge, deposited in our laboratory and inoculated onto SAC. With a hydraulic residence time (HRT) of 4 h, the handling capacity of the BAC reactor was approximate 72 m3/d.…”