Norlex Chemicals detack team helped a large Swedish company with a complete solution for improving their wastewater treatment processes.

Summery

Client: Paint shop, automotive industry.
Painting:
manual & automatic plastics PC, ABS, PP, PA, thermoplastics, aluminium and other metal components.
Paints: primers, basecoats and clearcoats / water based, solvent based and 2 components.
Systems: 3 paint wet scrubber cabins with one single flotation system.
Improvements made to system: stable operation, improved painting quality, green chemistry, training, automation, max removal efficiency, reduced paint sludge, reduced cleaning, substitution of biocide with improved control.
Read more about results

Before system implementation

Flotation unit return

Flotation unit removal

Dosing system

Foam control

After system implementation

Flotation unit return

Flotation unit removal

Dosing system

Foam control

Background

Norlex chemicals was contacted by Swedish company specialized in surface treatment, with strong focus on plastic and composites. They have paint shops in Europe with customers found in the global automotive industry.
The company had issues with the performance of their wet-scrubber system and the removal of paint overspray solids.

The Challange

The challenges on the current system were identified:

  • Simple chemical treatment with one detackifier designed for solvent based paint
  • Simple dosing system which is not slaved to real painting signals
  • Lot of manual dosing of detackifier, flocculant and defoamer to compensate for bad performance
  • One flotation system for all three paint cabins which results in a challenge due to the high hydraulic load (3 times more than best practice and design)
  • Hyrdopurge contaminated solvents where dumped into the process water causing foaming and instability
  • Foam issues resulting in unstable paint booth parameters and pure painting quality
  • Bad recycled water quality (flotation unit return) due to unsuitable chemical treatment specially for water based paints
  • Bad removal efficiency resulting in sedimentation and deposit in all water related parts and increased maintenance and cleaning efforts
  • High water content in the removed paint sludge due to bad dewatering properties specially when water based paint is sprayed
  • Bad odour despite the use of biocide (Isothiazoline based) which is a risk for the operators
  • Unstable chemical consumptions

Lab work

Jar testing was conducted to evaluate a chemical treatment program for a potential trial start after summer shutdown.

Main results from jar test:

  • Bentonite alone was tested with bad results on all water-based paints and good results on all solvent based paints. Dosing required with our DTB-10e is 40% x paint overspray solids
  • DTM-3713e as main detackifier with DTB-10e as support detackifier for solvent based paint was giving very good results on all tested paints. Dosing DTM-3713e was 25% x paint overspray solids and dosing DTB-10e was 10% x paint overspray solids.
  • Both ready to use flock like FPB-19, FPA-19 and dispersion flock like FPH-60h as 1% solution were giving very good results with fast flotation and clear water phase
CC-SB
BC-SB
BC-WB
PR-WB

The solution

Norlex Chemicals proposed a solution including upgrading the dosing system with chemical pumps detackifiers, flocculant, defoamer, pH adjustment, micro-biocontrol for each paint booth to be able to dose chemicals based on painting signals from both automatic and manual painting proportional to the need.

The chemical treatment was setup like the following:

  • DTM-3713e as main detackifier for all paint types / this have later been replaced by DTM-3750e
  • DTB-10e as support detackifier for solvent based paints and flocculation aid
  • FPB-19 as ready to use flocculant / this have been later replaced by the dispersion flocculant FPH-60h in combination with an automatic dosatron based polymer dilution unit
  • CGB-07 as pH control and coagulation support aid
  • DFO-80 as mineral oil free defoaming agent / later replaced by the mineral oil free DFO-91
  • BAC-100ep as micro bio control and cleaning agent

Training and control measurement

During the trial phase Norlex Chemicals implemented technical training for operators, plan for trouble shooting / technical support and continuous improvement plan including control measurements to reach the following goals:

  • Increasing removal efficiency
  • Reducing maintenance and cleaning
  • Reduce paint sludge waste
  • Stabilizing air balance
  • Stabilizing chemical treatment
  • Substitution of hazardous chemicals
  • Cost management process

Results

The result was very satisfying for the customer, with a significant increase in the removal efficiency and the implementation of a full green chemical program.
  • Stable chemical treatment due to automatic and proportional chemical dosing and technical training
  • Good follow up and control by operators
  • Reduced significantly manual use of chemical treatment chemicals
  • Removal efficiency increase from < 50% to >75%
  • Paint sludge dryness increased from <40% to >55%
  • Cleaning and maintenance reduced by >25%
  • Increased painting quality
  • Improved paint booth process parameters (air balance)
  • Good foam control
  • Good micro-bio and odour control with no use of biocides
  • Full green chemical program
  • Substitution of biocide which is hazardous to operators
  • Substitution of mineral oil and solvent based treatment chemicals
  • Stable chemical treatment which is proportional to paint consumption and paint types used
  • Sufficient hydropurge treatment