Thaum cov khoom nyob rau hauv lub ncua kev kawm ntawv yog loj thiab sib xws nyob rau hauv loj, lub pores ntawm lim slag txheej kuj du, thiab qhov ceev ntawm lub filtrate dhau los ntawm lub slag txheej yog kuj siab. Kev siv cov coagulants kom sib sau cov khoom zoo rau hauv cov pawg loj dua yog qhov zoo rau kev txhim kho pom kev ceev.
Rau kev tshem tawm nrog kev ceev ceev ntawm cov khoom siv, lub tshuab lim yuav tsum tau siv los pub rau sab sauv ntawm cov lim dej nruab nrab, kom cov kev taw qhia lim tau zoo raws li cov kev taw qhia lub ntiajteb txawj nqus. Coarse hais daws ua ntej, uas tuaj yeem txo qhov txhaws ntawm cov lim nruab nrab thiab lim cov seem seem; Kev sib xyaw coarser cov khoom xws li lub ntiaj teb diatomaceous thiab nthuav dav perlite mus rau hauv qhov nyuaj rau lim tshem tawm (xws li colloids) tuaj yeem ua rau cov lim dej seem seem xoob; Thaum lub viscosity ntawm lub filtrate yog siab, lub ncua kev kawm ntawv yuav rhuab kom txo viscosity. Cov kev ntsuas no tuaj yeem ua kom nrawm nrawm nrawm.
