Solid-liquid Separation

Wastewater and sludge are usually mixtures of solid components and

liquids. The liquid phases almost always also contain solute substances.

waste water, sludge, suspensionWhereas the solute components cannot be removed, at least not right

away (see heading Adsorbents), small particles are also frequently

difficult to remove to a sufficient degree.


This problem is addressed on the one hand by means of suitable technical equipment such as


  • Centrifuges
  • Chamber presses
  • Belt presses
  • Revolving screens and belt filters
  • Filters
  • Flotation


flocculant agents, polymere, solid components, solute substances but in most cases a chemical conditioning of the medium to be dewatered

is necessary to achieve more rapid and effective separation.


The chemical conditioning process functions according to the principle

of the mutual attraction of particles with opposing charges. The

surfaces of all solids in suspensions carry either a positive or a

negative charge. The conditioning agents (usually high-molecular, i.e.

polymers or coagulants) must optimize the polarized charge effect by

creating a balance of charges within the system (isoelectric point).