Wastewater treatment for fish oil and fish meal producer

Scenario

PROMARINA SA is located in Puerto Caimito (Panama), producing fishmeal and fish oil. In the production process, the fish is steam-cooked, then press-dried to separate the oil and finally dried and the solids are ground. The factory uses seawater to transport the fish from the fishing boat to the production plant. The volume of wastewater is 2,560 m3 per day (in one shift).

As part of the company's commitment to the environment, PROMARINA built an Effluent Treatment Plant (ETP) with coarse and fine screening in perforated drum separators and coarse bubble flotation clarification of wastewater with high salt, oil and grease content before being discharged into the sea.

SIGMADAF was contracted directly by PROMARINA for the design-supply of the equipment to be installed in the existing PTE, including primary flotation equipment for the separation of oil and grease in a first separation tank, this to replace the existing equipment of lower efficiency, followed by a new coagulation-flocculation with chemical dosing, followed by 2 DAF FPAC100 units that function as high performance clarification treatment.

Pre-Flotation 

This treatment stage is performed using existing tanks with SIGMADAF equipment to generate air bubbles, including recirculation pump, pressurization, aeration and bubble distribution. The solids and grease separated in this tank are taken back to factory production, as they do not contain any chemicals. 

Physical-chemical treatment

After pre-flotation, the wastewater flows into a storage tank for flow lamination and is then pumped to physicochemical treatment. This is done by dosing acid for pH adjustment, a coagulant (ferric chloride) and a polyelectrolyte into SIGMADAF PLUG-FLOW inline tubular flocculators PFL-100, for continuous mixing of the chemicals with the wastewater along the length of the tube to enhance the formation of larger flocs prior to the flotation process. The tube diameter and length are selected to achieve sufficient water-chemical contact time and velocity for gentle floc formation. Each DAF has its own tubular flocculator.

DAF FPAC-100 High Performance

The SIGMADAF FPAC is a reduced draft piston flow flotation tank designed to treat wastewater with high suspended solids loads and high mass loading. To enhance the solids separation process by flotation, air is introduced in the form of fine bubbles with a size of 30 to 50 microns, which adhere to the solids.

The floated solids are collected on the surface of the tank by a chain scraper that sweeps the froth into a collection hopper at the outlet, with a concentration of up to 4 - 5% solids before flowing to the sludge treatment. The solids settling in the tank are removed through a screw installed at the bottom of the tank, connected to an automatic drain valve. The sludge separated in the DAF is estimated at 300 m3/day which is dewatered in a decanter centrifuge. 

SIGMADAF's scope of supply included DAF equipment, feed pumps, piping and valves, sludge pump, sludge dewatering centrifuge, chemical preparation and dosing, agitators, instrumentation for level, flow, pH, pneumatic panel, electrical cabinet (MCC) and control panel with PLC, cabling, transportation, spare parts, supervision during assembly installation, commissioning and training, as a complete turnkey scope.

Wastewater design features

Performance