Dr. Bilous is a specialist in identification of phytoplankton and phytobenthos using different methods as light microscopy and scanning electron microscopy. She conducted her identifications of algae for different waterbodies: from riverine landscapes to lakes and reservoirs from different geographical locations with special ecological conditions (Ukraine, Italy, Germany).

She has conducted ecological status assessment of different water bodies based on her algological findings (phytoplankton, phytobenthos) and hydrochemistry following EU Water Framework Directive requirements. Dr. Bilous Olena has been assessing ecological and chemical status of representative surface water bodies, making pressure and impact analysis and risk assessment of the surface water and groundwater bodies, setting reference conditions and mapping protected zones (territories) – for the Siversky Donets, Dniester River basin, Southern Bug River, Sasyk, Kyiv, Kaniv reservoirs, springs in Berchtesgaden National Park and Northern Apennines.