TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The process additionally involves acclimatization of biomass for oxidizing the bisphenol compound prior to operation of the membrane bioreactor for reducing bisphenol compound content in wastewater. The volumetric load is 86.4 g m-3 d-1. In membrane bioreactor, chemical oxygen demand (COD) is maintained to 500-1500 (preferably 1000) mg/L. The hydraulic retention time of membrane bioreactor is 3-6 (preferably 6) hours. The organic loading of membrane bioreactor is 0.3-2.1 kg COD/kg VSS/d. The acclimatization is by performing a gradual addition of the bisphenol compound over a time to obtain a biomass capable of oxidizing the bisphenol compound. The monitoring and regulating is performed by measuring a concentration of bisphenol compound of wastewater and measuring the flow rate of membrane bioreactor. Preferred Components: The biomass has VSS concentration of 1.5-19 (preferably 10-15) g/L. The bisphenol compound content in wastewater is up to 10 mg/L, or 1-25 (preferably 1-20) mg/L. The COD is maintained with a source of carbon chosen from sodium acetate, peptone, glucose, saccharose, starch, casein, and/or sodium dodecyl sulfate. The gradual addition of bisphenol compound is 1-15 mg/L. The bisphenol compound is chosen from 2,2-bis(4-hydroxyphenyl)propane (Bisphenol A), 1,1-bis(4-hydroxyphenyl)-1-phenyl-ethane (Bisphenol AP), 2,2-bis(4-hydroxyphenyl)hexafluoropropane (Bisphenol AF), 2,2-bis(4-hydroxyphenyl)butane (Bisphenol B), bis-(4-hydroxyphenyl)diphenylmethane (Bisphenol BP), 2,2-bis(3-methyl-4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)-2,2-dichlorethylene, 1,1-bis(4-hydroxyphenyl)ethane (Bisphenol E), bis(4-hydroxydiphenyl)methane (Bisphenol F), 2,2-bis(4-hydroxy-3-isopropyl-phenyl)propane (Bisphenol G), 1,3-bis(2-(4-hydroxyphenyl)-2-propyl)benzene (Bisphenol M), bis(4-hydroxyphenyl)sulfone (Bisphenol S), 1,4-bis(2-(4-hydroxyphenyl)-2-propyl)benzene (Bisphenol P), 5,5'-(1-methylethyliden)-bis(1,1'-(bisphenyl)-2-ol)propane (Bisphenol PH), 1,1-bis(4-hydroyphenyl)-3,3,5-trimethyl-cyclohexane (Bisphenol TMC), or 1,1-bis(4-hydroxyphenyl)-cyclohexane (Bisphenol Z) (preferably Bisphenol A). EXAMPLE - No suitable example given.