Treatment of rinsing water from degreasing baths

Our Client is a manufacturer of household equipment including cookware and kitchen electrics. The manufacturing process of their products implies a surface treatment process and several stages of rinsing at the end of production. Our Client generates up to 24,000 L of wastewater daily.


A manufacturing process involving several rinsing phases

Our Client is a manufacturer of household equipment including cookware and kitchen electrics. For example, our Client produces frying pans, oven dishes, pressure cookers, pots, deep fryers, induction cooktops, and others. The manufacturing process of their products implies a surface treatment process and several stages of rinsing at the end of production.

The washing baths must be supplied with demineralized water at a rate of 1 m3/h and in a conductivity range of 0.3 to 50 microsiemens. The washing tunnel in question generates wastewater at a rate of 300 L/h. With five washing tunnels operating in two 8-hour workstations, our Client generates up to 24,000L of wastewater daily. This washing water is mainly loaded with cleaning products, oils, greases, metal particles and abrasive dust.


Without a wastewater treatment station, washing water must be stored before being withdrawn for disposal by an external service provider, involving relatively high disposal and reprocessing costs. Our Client calls on the NISKAE team to determine a suitable physicochemical treatment solution for the treatment and discharge of their rinsing water, in accordance with the current regulations.

Conclusive analysis results

Several representative samples of the washing water are collected on site and sent to our laboratory experts. A set of flocculation tests and analyzes are thus carried out in order to obtain a coagulant-flocculant formulation corresponding to the specific needs of our Customer.

The sample from the first degreasing bath is initially opaque in appearance and gray in color. The addition of a coagulating and flocculating mono-reagent, with a minimal dosage of 2.0 g/L, allows the filtrate after treatment to be clear, clean and translucent. The reaction is achieved within a few minutes with a decrease in the iron concentration from a value of 1.22 mg/L to a lower concentration of 0.01 mg/L.

For the second degreasing bath, the sample received is characterized by its slight yellow and brown tint. The same coagulant-flocculant product determined for the first sample is applied at a dosage of 1.0 g/L. The water after treatment is clear, clean and translucent. The concentrations of heavy metals, especially for iron and copper, are lowered to values below 0.01 mg/L.
 
The treatment sludge from the two tests is stable and easily dehydrated for application on a filter press.


An adapted and economical solution

The use of a single specific coagulant-flocculant formulated by the NISKAE laboratory allows a suitable treatment for the mixing of different sources of effluents. Our Customer will be able to use a single, ready-to-use coagulant-flocculant product for minimal dosages of the order of 1 to 2 grams per liter. These minimal dosages allow in all efficiency the reduction of the heavy metal contents and the discharge in full compliance with the regulations in force.


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