Lanthanum　(La)　adsorbents　are　highly　effective　for　phosphorus　removal　but　are　constrained　by　their　high　reagent　cost　because　of　their　La　content.　By　exploiting　the　similarity　in　ionic　sizes　between　Ca2+　and　La3+,　we　develop　a　low-cost　composite　adsorbent　LCCa-5@Dia　by　doping　La2(CO3)3　&　sdot;8H2O　with　Ca2+.　Our　results　indicate　that　the　slow　addition　of　NaHCO3　during　the　synthetic　process　facilitates　the　incorporation　of　Ca2+　into　the　La2(CO3)3　&　sdot;8H2O　lattice,　leading　to　an　adsorption　behavior　nearly　identical　to　that　of　the　undoped　adsorbents.　LCCa-5@Dia　demonstrates　a　high　adsorption　capacity　of　60.04　mg　P/g,　with　stable　performance　across　a　pH　range　of　3　to　11.　Its　adsorption　property　also　exhibits　excellent　stability　under　the　interference　of　solution　pH　and　competing　ions.　Materials　characterization　reveals　that　the　adsorption　occurs　through　electrostatic　attraction　and　ligand　exchange.　In　continuous　column-adsorption　experiments,　the　LCCa-5@Dia　adsorbent　treats　up　to　4000　bed　volumes　of　simulated　low　concentration　wastewater　(1.7-2.7　mg　P/L).　This　translates　to　a　treatment　cost　as　low　as　$0.0211/m3.　Meanwhile,　the　adsorbent　also　maintains　over　80　%　of　the　adsorption　capacity　after　three　regeneration　cycles.　The　excellent　performance　and　low　treatment　cost　of　the　calcium-doped　lanthanum　carbonate　adsorbents　highlight　its　practical　potential　in　treating　low　concentration　wastewater.