Upgrading of a beverage industry wastewater treatment plant using a DAF

Characteristics of the effluents to be treated

The discharges to be treated have a TSS content > 3,000 mg/l.

Description of supply

RETEC, a water treatment company, purchased from SIGMADAF clarifiers the supply of flotation equipment to improve wastewater treatment for the PEPSICO beverage industry in Cologne.

The scope of supply includes: A SIGMADAF FAPC15 assembly consisting with metal body, flocculant scraper system, recirculation pumping assembly with pressurized air injection manifold. A pneumatic control panel and an in-line flocculant preparation and dosing equipment in a contact coil PFL010 are provided. Engineering documentation and installation manuals are also provided. Typical performance of the supplied equipment achieves >90 % TSS reductions, operating under correct conditions and with proper chemical conditioning.

Basic features

• Equipment: SIGMADAF FPAC15
• Materials: AISI 316 /AISI 304                         
• Dimensions: 4,000 x 2,200 x 1,500 mm (L x W x H)               
• Design flow rate: 5 - 15 ^m3/h
• Free area: 4.25^m2
• Hydraulic load: 1.17 - 3.52 ^m3/m2/h
• Mass loading: 3.52 - 10.58 ^kg/m2/hç
• Air consumption: 6 Nl/min.
• Power consumption: 7 kW
• 0.37 kW surface scraper system
• Pressurization and recirculation pumping 7.5 kW

The dissolved air flotation (DAF) technique allows the separation of suspended solids, oils and fats, thanks to the recirculation of part of the treated wastewater, to which pressurized air is injected and then depressurized in the liquid, thus creating a stream of micro air bubbles (30 - 50 µm) that adhere to the particles, causing them to rise as they lose apparent density.          

DAF FPAC flotation equipment with large surface area and crossflow separation

The DAF FPAC is ideal for working with small and medium flows, containing high pollutant loads (up to 40 kg of ^MS/m2). They are also the most suitable model for sludge thickening. They have a large free surface to accumulate the floated sludge.

SIGMADAF technology is used to separate oils, greases, suspended solids and flocculated matter, which do not have sufficient flotation capacity or when oil-solids emulsions (with high density) require air flotation to improve the separation process.  

The FPAC model includes a single separator motion that rotates against the hydraulic current, helping to minimize the distance the floated sludge travels and eliminating solids carryover in the effluent. This solution creates a sludge with a dry solids content 3 to 4 times higher than a conventional system. This results in a simplification of possible subsequent treatments, such as dewatering or drying, which reduces operating costs.

Heavy sludge, which settles to the bottom of the system, is retained, concentrated and partially dewatered with the shaftless conveyor system. This allows the operator to control the concentration of the sludge and reduce its accumulation. The residual sludge is conveyed to the central discharge point and removed through an automatic pneumatic valve. This discharge cycle has a self-cleaning effect, which facilitates any particles adhering to the walls of the system to be released and removed with the rest of the waste.

Main features of DAF FPAC15 equipment

• Compact and customizable system.
• Treatment of high loads of TSS and other contaminants.
• Efficient laminar regime.
• Low maintenance and easy to operate.