Bacterial　suspension　is　an　essential　component　of　microbially　induced　carbonate　precipitation　(MICP)-based　biocement　and　a　large-scale　production　is　required　for　field　applications.　In　this　study,　a　new　bacterial　concentration　method　is　proposed　to　enable　high　concentration　bacterial　suspension　to　be　produced　to　facilitate　field　work.　By　adding　low　concentration　calcium　to　bacterial　suspension,　flocs　are　formed　and　bacterial　cells　are　adsorbed　on　the　flocs　to　achieve　bacterial　concentration.　Compared　to　the　traditional　bacterial　concentration　method　using　centrifugation　and　freezing-drying　method,　the　proposed　method　can　concentrate　a　large　volume　of　bacterial　suspension　without　using　special　equipment.　The　feasibility　of　this　method　is　verified　by　bacterial　concentration　tests,　solution　tests　and　sand　column　treatment　tests.　The　results　of　both　the　solution　test　and　the　sand　column　treatment　test　show　that　the　bacterial　suspension　concentrated　by　the　proposed　method　can　be　effectively　used　for　soil　biocementation.　There　is　a　threshold　calcium　concentration　that　allows　a　complete　bacterial　concentration　for　the　proposed　method,　and　this　threshold　calcium　concentration　tends　to　increase　linearly　with　the　optical　density　of　the　cell　suspension　at　a　wavelength　of　600　nm　(OD600).　©　2024　Institute　of　Rock　and　Soil　Mechanics,　Chinese　Academy　of　Sciences