Removal of small impurities to meet discharge limits

  • Easy integration in existing systems
  • Reliable and low maintenance operations
  • Prefabricated solution and easy to install


For the final polishing of the wastewater to meet very stringent discharge limits or to have optimization on the existing treatment system there are several single products available which can be add to the design of the water treatment.


Sand filter

Sand filtration is used to remove solids, precipitates, turbidity (muddiness) and in some cases bacterial particles that produce bad taste and odour. It is a form of natural, biological water treatment. The sand filters consist of a bed of graded sand. The filter media is stored in a tank with openings at both ends allowing water to flow in and out. Depending on the raw water quality, the biological layer develops in a short time after filter is taken into operation.

A good filtration depends on the size of the flock, the amount and the composition of the floating elements. The quality of sedimentation is also important. If flock forming is insufficient, a chemical dosing can be installed.

One of the main advantages of these filtration types is the filtration depth. In fact a very thick filtration layer is created. The bulk of the particles are caught at the top of the filter. Smaller particles however will initially pass through this. But because of the deep sand bed, they will finally be filtered out of the water.

Carbon filter

Activated carbon is effective in reducing certain organic compounds and chlorine in water. It can also reduce the quantity of lead, and harmless taste and odor causing compounds.

The removal of contaminants by activated carbon is accomplished by the process of adsorption. Contaminants are adsorbed by the enormous surface the carbon offers.

The process of adsorption is also influenced by the length of time that the activated carbon is in contact with the contaminant in the water. Increasing contact time allows greater amounts of contaminant to be removed from the water. Contact is improved by increasing the amount of activated carbon in the filter and reducing the flow rate of water through the filter.


To inactivate or kill any bacteria and viruses present in the effluent, the effluent will be disinfected prior discharge or further treatment. Disinfection can be executed in several ways, most used are disinfection by means of chemicals, ultraviolet light or ozone. Based on water quantity, quality and needed results the optimal solution will be chosen.


Marel offers a range of service solutions to prevent failures, maximize performance or in case of unexpected breakdowns remote or onsite assistance.

Marel has offices in 30 countries across all regions, and a global network of highly skilled professionals that provide remote as well as onsite service support. We provide quality spare parts and customized service agreements for our customers to ensure optimal performance of Marel equipment.

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