Wastewater treatment in the manufacture of flooring

• 1. Characteristics of the effluent generated during the manufacture of flooring
• 2. Compact treatment plant: DAF system + filter press
• 3. Plant operations
• 3.1. Power Supply and Flow Control
• 3.2. Physical-chemical treatment
• 3.3 Dissolved-air flotation
• 3.4. Sludge Management and Dewatering Using a Filter Press
• 4. Results obtained

1. Characteristics of the effluent generated during the manufacture of flooring

The wastewater generated during the production of paving materials contains a wide range of contaminants, making its treatment complex and requiring a high degree of customization in the design of the treatment plant.

In this case, the effluent contains suspended solids, oils, fats, organic matter, and metals. The high concentrations of TSS, COD, BOD, and oils require a treatment process capable of ensuring effective solid-liquid separation, stabilizing the process, and reducing the final volume of sludge generated.

Characteristics of the wastewater to be treated:

• Maximum daily flow: 175 m³/day
• Average daily flow: 120 m³/day
• Maximum hourly flow rate: 13 m³/h
• Total suspended solids (TSS): 380 mg/L
• Oils and fats: 63 mg/L
• COD: 1,575 mg/L
• BOD: 260 mg/L
• Zinc: 1.2 mg/L
• pH: 7.2
• Temperature: 20–25 °C

Effective separation of these contaminants is essential to prevent discharge issues, regulatory violations, overloading of sewer systems, and high waste management costs.

To address this need, Sigmadaf has designed and manufactured a compact plant that incorporates a physicochemical process capable of treating high concentrations of suspended solids, oils, fats, and organic matter, along with a sludge dewatering system using a filter press.

The main technical challenges of the project were:

• Reliably remove suspended solids and oils.
• Reduce the organic load (COD and BOD).
• Control chemical dosing based on actual process parameters.
• Integrate a compact system with automatic sludge management.
• To provide a solution that ensures quick and easy implementation
• Minimize operator intervention.
• Ensure operational safety and equipment protection.

This solution made it possible to streamline the process, reduce waste volume, and ensure a fully automated, safe, and stable operation.

2. Compact treatment plant: DAF system + filter press

The implemented solution combines a compact physical-chemical treatment plant with dissolved air flotation (DAF) and a sludge dewatering system using a filter press.

The system includes:

• Homogenization tank with controlled feed.
• Compartmentalized physicochemical reactor (coagulation, neutralization, and flocculation).
• DAF system for solid-liquid separation.
• Automatic management of flotation and settled sludge.
• Sludge storage tank
• Automatic filter press with programmable cycles.
• Comprehensive control via HMI with multiple safety parameters: alarms, emergency stops, etc.

3. Operations at the wastewater treatment plant for the flooring manufacturing industry

Mechanical sludge drying involves a set of solid-liquid separation technologies aimed at reducing the water content in sludge through the application of mechanical solutions. The choice of the most suitable process depends on the nature of the sludge, the flow rates to be treated, the degree of dryness required, and the investment and operating costs.

3.1 Power Supply and Flow Control

Wastewater is homogenized in a receiving tank with continuous agitation. The system automatically controls the levels to prevent overfilling or dry running. The inflow rate is regulated by a pump and a proportional valve, which can be adjusted via the HMI screen.

3.2. Physical-chemical treatment

Three key stages take place in the compartmentalized reactor:

• Coagulation: automatic dosing of coagulant.
• pH adjustment: Caustic soda is dosed only when the measured value is below the set point.
• Flocculation: controlled addition of pre-diluted polymer.

Frequency-controlled agitators ensure optimal mixing and efficient floc formation.

3.3 Dissolved Air Flotation – DAF

Solid-liquid separation takes place inside the DAF system. The floated sludge is automatically conveyed to the sludge hopper. The process is fully automated and monitored by pressure and level sensors.

A small portion of the sludge generated inside the DAF tank cannot be separated by flotation, so it must be periodically drained using a sludge extraction pump to prevent it from accumulating inside the unit.  

                          

3.4. Sludge Management and Dewatering Using a Filter Press

The sludge produced is sent to a storage tank equipped with an agitator for homogenization and chemical treatment.

It is then sent to a mixing tank upstream of the filter press, where the following parameters are monitored:

• Level
• Agitation
• Additional dosing of flocculant
• Pre-conditioning time

The filter press can operate in either manual or automatic mode, performing a complete cycle that includes:

• Hydraulic lock
• Dual-speed feed
• Air purge
• Drying
• Decompression
• Opening
• Automatic plate shaking
• Automatic restart in continuous mode

This system produces dewatered sludge with a high solids content, significantly reducing the final volume to be managed.

4. Results obtained

The plant's construction enables:

• Effective reduction of suspended solids and oils
• Significant reduction in organic load
• Stable separation using DAF technology
• Production of dewatered sludge with a smaller volume, reducing waste management costs.
• A 100% automatic filter press that minimizes the need for manual intervention by operators.
• Optimization of chemical consumption
• High security and operational stability
• Installing compact equipment optimizes floor space.

The result is a compact, efficient, and highly automated plant designed to maximize contaminant removal and sludge reduction in demanding industrial environments.