Wastewater management for the vegetable processing industry

The cleaning of the raw material is an operation which can be carried out one or several times throughout the process in order to eliminate undesirable substances.

The water used in the production process must be treated before being discharged. This way the volume of wastewater generated is important.

Regarding the pollutant load of these discharges which basically contains organic matter and solids in suspension, its presence and concentration depend on several aspects: type of raw material, production system employed, level of production, type of industry, etc.

For a salad packaging plant (lettuce, broccoli, spinach, kale) located on the outskirts of Warsaw (Poland), Salher has proposed in 2011 a facility with a capacity of up to 100 m³/day which includes:

• A pumping station with a flow meter
• Pre-treatment prior to the secondary treatment with the helical screw. (Reference: TA-HEL),
• Secondary treatment of low load active sludge, with nitrogen removal by biological means (nitrification – denitrification) and clarification process in compact tank (Reference: CHC-OXI-REC-C-ANOX),
• Biological sludge storage tank,
• Oximeters,
• Deodorization, reference CARBO-SAC.

Due to an increase in the production, the plant again required the engineering services of Salher.

The new WWTP designed, manufactured and set up by Salher has a treatment capacity of 400 m³/day and has the following elements:

• Conversion of the installed tank in the anoxic chamber to eliminate nitrogen.
• Use of the pumping station, electromagnetic flow meter and a screening system with automatic cleaning.
• Conversion of the secondary treatment to a MBBR system (moving bed biological reacto ) with adjacent chambers and lamellar independent clarifier. 
• Maintenance of the biological sludge tank.