混凝劑一般來講是無機的鹽類如鐵鹽、鋁鹽，主要作用機理是帶電粒子中和膠粒，使得膠體脫穩形成絮狀體顆粒，原則上已經可以達到去除懸浮污染物的目的。而絮凝劑一般來講是指高分子有機聚合物，這類物質具有線型結構，在機理上是將已經形成的小顆粒的絮狀體鏈接起來，從而形成更大的顆粒，加速沉降，因此也成為助凝劑。

Generally speaking, coagulants are inorganic salts such as iron salts and aluminum salts. The main mechanism of action is to neutralize the colloidal particles by charged particles, so that the colloids are destabilized to form floc particles. In principle, the purpose of removing suspended pollutants has been achieved. . Generally speaking, flocculants refer to high molecular organic polymers. These substances have a linear structure. In mechanism, they link the formed flocs of small particles to form larger particles and accelerate sedimentation. Therefore, Also become a coagulant.