A method of controlling and removing biofilm on a surface in contact with an aqueous industrial system comprising the step of adding an effective amount of biofilm-disrupting agent and adding a biocide to the aqueous system being treated to reduce and remove biofilm forming microbes from a surface in contact with the aqueous system is disclosed. Also disclosed is a synergistic composition of polyethyleneimine and an oxidizing biocide.本發明揭示一種控制及移除與水工業系統接觸之表面上的生物膜的方法,其包含以下步驟:向所處理之該水系統中添加有效量的生物膜干擾劑且添加殺生物劑,以自與該水系統接觸之表面減少及移除形成生物膜之微生物。本發明亦揭示一種聚乙亞胺及氧化殺生物劑之協同組合物。