Biological phosphorus removal from potato processing industrial wastewater (BioPOM)

The BioPOM project aims at the application of Enhanced Biological Phosphorus Removal (EBPR) from potato processing industrial wastewater. The EBPR process not only reduces the amount of chemicals needed for phosphorus removal, but also significantly lowers the salinity of the treated water, thus allowing reuse of the treated effluent for irrigation purposes.

Keywords:WASTEWATER TREATMENT, PHOSPHORUS

Disciplines:(Waste)water treatment processes

Results:In the intricate interplay between industrial advancement and environmental responsibility, wastewater treatment stands out as a formidable challenge. In Flanders, Belgium, the VLAREM II articles regulate environmental matters, including emission standards, waste management, and discharge limits for industrial activities. This includes wastewater derived from potato processing, which is the focus of this research. Laden with heightened concentrations of COD, nitrogen (N), and phosphorus (P), this effluent can pose an imminent threat to ecosystems if insufficiently treated. While traditional approaches favor physical or chemical nutrient removal, this study focuses on exploring the efficacy of biological nutrient removal (BNR) processes, including enhanced biological phosphorus removal (EBPR), nitrification, and denitrification, providing a sustainable and cost-effective alternative. The research focuses on establishing a lab-scale Sequencing Batch Reactor (SBR) cycle for concurrent microbial nitrogen and phosphate removal, utilizing wastewaters from the potato processing industry. In the initial phase of this research, the primary objective was to assess the feasibility of establishing a microbial treatment cycle for the anaerobic digester effluent (low COD, high N and P – referred to as “effluent”), using sodium acetate as a carbon source. Subsequently, the investigation progressed to a second step, where the anaerobic digester influent (high COD, N, and P – referred to as “influent”) was introduced into the SBR cycle as the carbon source. Following these successful demonstrations, the study shifted towards fine-tuning the SBR cycle for optimal performance. Two SBRs, “A” and “B”, operating as a reference and experimental unit respectively, were used to systematically test for optimal aeration and feed times. It was quickly established that shorter alternating aerobic/anoxic phases and split effluent/influent feedings at the start of the cycle worked best for achieving optimal performance in nutrient removal. Additionally, as the influent wastewater is also used for biogas production, the optimization of its carbon use necessitates its minimal usage in the BNR system. This was tested by feeding various effluent to influent wastewater ratios (2:1, 2.5:1, 3:1, 3.5:1, and 4:1) to both SBRs, to fully test out the various cycle methods being examined. Starting with a 2:1 ratio to optimize polyphosphate-accumulating organism (PAO) function, ratios were incrementally increased once a ratio had reached stable conditions. In each feed ratio phase, COD and N removal consistently remained high (over 90%), while P levels varied between the SBRs. Reactor A exhibited more stable results (80-100% removal efficiency) compared to Reactor B, which showed higher P removal fluctuations (47-99% removal efficiency). Both reactors were given ample time to adjust after each ratio change. The findings suggest that the original reference cycle design (SBR A) offers more consistent and robust removal efficiencies. Ongoing investigations aim to confirm if these results continuously align with strict VLAREM II discharge regulations both over longer periods of time and with wastewater from other potato processing companies. This research aligns with the broader challenge of wastewater treatment in the potato processing industry and contributes to the understanding and implementation of sustainable practices. By evaluating biological nutrient removal processes insights for alternative wastewater treatment strategies can be made, ensuring compliance with regulations and safeguarding water resources. Process optimization in the lab along with the plans for an industrial scale-up show the potential of a biological approach in terms of efficient wastewater treatment.