Once reached 100% of COD concentration in the batch reac-tor, feeding of wastewater stopped; and biologic degradationof the wastewater started. Daily, volume samples of 15 mLwere taken from the reactor, (representing less than 5% ofthe total reactor volume); an equivalent volume of untreatedwastewater was added to the reactor to complete the vol-ume reaction. Samples were analyzed in triplicate for CODand BOD concentration, as well as pH, alkalinity, TSS, turbidityand color; also methane yield was monitored. Methane yieldor methane production rate (mL CH4(g COD)−1) was deter-mined by the linear regression analysis from the experimentaldata, accumulated volume of CH4(mL) and COD removed(g) during the test period, adjusted by the method of leastsquares.