Dear Ahmad, COD is an ...

Dear Ahmad,

COD is an important parameter for anaerobic digestion, if the COD is too low the methane production will be low too. it is also important take into account the kind of reactor, the retention time, the temperature. Usually for wastewater the reactors most appropriate are UASB or EGSB, working at low HRT, because the COD of urban wastewater usually is lower than 1000 mg COD/L..Depends on your objective. If you main goal is to recover biogas from the wastewater, the high concentration from 1,000-50,000 mg/L or even higher will be OK. Considering solubility of methane in water (20-30 mg/L), a low concentration is not good for methane recovery. If you focus only on COD removal, low concentration even < 100 mg/L would be OK. The COD is really not important parameter from anaerobic digestion efficiency point of view. The parameters like organic dry matter, N-NH4 content, C:N ratio, HM content play much more important role. a minimum COD is also required at least to produce enough methane to heat the reactor.

The 50 ppm COD is very less hence the Pre-treatment is sufficient.

Mechanically emulsified oil most economically. 12ppp can be removed by activated carbon.