Phosphorus removal from soy protein wastewater using novel crystallisation technology.

Area of Science:

• Environmental Engineering
• Chemical Engineering
• Water Treatment Technologies

Background:

• Soy protein isolate manufacturing generates wastewater with high phosphorus content.
• Stringent regulations necessitate phosphorus reduction in industrial wastewater discharge.
• Existing treatment methods may increase soluble salts or be inefficient.

Purpose of the Study:

• To identify and implement a wastewater treatment method to reduce total phosphorus (P) to 2 mg L(-1).
• To achieve phosphorus reduction without increasing soluble salt concentrations.
• To comply with environmental discharge and receiving-water requirements.

Main Methods:

• Evaluation of a novel crystallization technology, the high-aspect ratio, draft tube crystalliser (HARDTAC).
• Pilot studies and full-scale implementation of lime precipitation at pH 10.0-10.2.
• Characterization of particle settling, filterability, and crystal size distribution.

Main Results:

• Achieved average total phosphorus reduction to 2 mg L(-1).
• Produced rapid settling particles (3.6 cm min(-1)) and filterable cake (65% dry solids).
• Minimal carbonate removal resulted in low sludge generation (0.6-0.8 g/L) and lime consumption (0.40-0.75 g/L).

Conclusions:

• The HARDTAC crystallization technology effectively treats soy protein isolate wastewater for phosphorus removal.
• The method meets stringent discharge limits without increasing soluble salts.
• The system offers an efficient and cost-effective solution for industrial phosphorus management.