Development of a model for PHA-based denitrification in a packed bed reactor

In the conditions tested, an average ratio of 2.92 g PHA to 1 g NO3−-N reduced was found. The model results showed a denitrification rate of 2.97 kg m−3 d−1 for ranges from 10 to 50 mg NO3−-N L−1. Using this model as a management tool, the required size of denitrification units and PHA recharging time can be predicted based on the expected nitrate loading and the time between PHA recharges desired. The unit sizing should be done for the maximum load expected. The slow rate and the energy required for PHA hydrolysis, make it unavailable as electron donor after the nitrate is consumed, so it will not promote the formation of sulfides. The model can be modified for other biodegradable non-water soluble medium by changing the hydrolysis constant, which must be determined experimentally.