Common is to look at getting in a pure oxygen supply - you used to be able to hire Vitox lances from BOC in the UK.

You could also look at using hydrogen peroxide. This might be rather more expensive, but for emergency use should be fine. You need to check the concentrations of hydrogen peroxide, as it becomes a dangerous fluid when the concentration rises and you must ensure that people using it are briefed and kept safe.

Dear Nimantha,

Jeremy is correct that H2O2 would work fine if you looking only to enhance the DO.You have to monitor the concentration as at higher concentration it acts as disinfectant too.

 But to keep alive the lifeline of microbe in case of emergency, one can use compounds containing NO3 (Nitrate), as in case of of depletion of DO .Oxygen can be obtain by de-nitrification of these salts by the microbes present in the system . You can use Sodium Nitrate, or KNO3.

thanks

dinkar

DAF system.