Treatment and recycling of washing water from paint production tanks for the aeronautics industry

Our Client, located in Belgium, is a manufacturer specialized in the production of water-based paints and coatings, mainly for the application of aircraft cabin interiors. The paint manufacturing process requires our client to wash and rinse the production tanks and mixers daily. This operation generates about 400 to 600 liters of wastewater daily. For the time being, the wastewater is stored before being removed for disposal by an external service provider. Storing such quantities involves significant costs, operating and handling time, as well as an environmental risk in the event of a leak or accidental spill.


The NISKAE laboratory develops a coagulant-flocculant formulation adapted to the type of effluent

Concerned about its image, our Customer wishes to obtain a solution answering its needs of treatment and recycling of its production cleaning waters. Several samples of wastewater from the washing operations were sent to the NISKAE laboratory in order to establish the most suitable coagulant-flocculant formulation given the nature of the effluents to be treated.

Thanks to the various tests and analyses carried out by NISKAE experts, a tailor-made flocculant reagent was formulated and requires a dosage limited to 2.5 g/L. The addition of a custom-made reagent at a low dosage allows to maintain the pH value in the ideal conditions for the coagulation and flocculation reaction.

Therefore, no pH regulation is necessary. The water treatment process is therefore simplified and the risk of handling reagents such as hydrochloric acid or sodium hydroxide is eliminated. Moreover, the proposed coagulant-flocculant complex allows a complete clarification of the treated water and a significant reduction of heavy metal concentrations. For example, the zinc concentration of 56.63 mg/L has been reduced to 0.02 mg/L. The resulting sludge is non-sticky and well dewaterable, which will allow the use of a gravity sludge dewatering system

A plan to install a treatment and recycling micro-station is proposed by NISKAE’s engineers

The technical study carried out both on site and in the laboratory enabled NISKAE engineers to propose and confirm a plan for the acquisition of a wastewater treatment and recycling plant. The proposed plant is the SW200 model with semi-automatic operation and motorized emptying, which in this case can treat a volume of wastewater of 400 to 600 L per day.

The proposed installation includes the following equipment:
  • A collection manhole for the washing water equipped with a range of float levels and a pump for the transfer of water to the station. In this case, our customer had a concrete manhole that we equipped with a custom-made polypropylene tank to prevent any infiltration into the soil.
  • ​The water coming from the collection manhole is then stored in a 1000 L tank equipped with an agitator to avoid any settling phenomenon and to ensure the good homogeneity of the water before treatment.
  • A 200 L reactor then allows the treatment by coagulation and flocculation. The filtration and dehydration of the sludge are carried out by a mobile filtration chamber.
  • The treated and clarified water is stored in a final 1000 L tank. An overpressure pump allows the water to be reused at the head of the high-pressure unit used for washing operations. The recycled water is filtered beforehand.

A return on investment ensuring the reuse of treated water

Our Customer now has an easy-to-use and efficient wastewater treatment plant. This investment allows him to reuse the water and to avoid major costs for the evacuation and treatment of the wastewater by an external service provider. The return on investment is assured!