Grantee Research Project Results
Final Report: Phosphorus recovery and high efficiency biological nutrient removal from wastewater with an innovative aerobic granular sludge sequencing batch reactor process
EPA Contract Number: EPD17018Title: Phosphorus recovery and high efficiency biological nutrient removal from wastewater with an innovative aerobic granular sludge sequencing batch reactor process
Investigators: Coleman, Thomas E.
Small Business: dTEC Systems LLC
EPA Contact: Richards, April
Phase: II
Project Period: March 1, 2017 through February 28, 2019 (Extended to February 28, 2021)
Project Amount: $300,000
RFA: Small Business Innovation Research (SBIR) - Phase II (2016) Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Water
Description:
The purpose of this SBIR research project was to develop and apply an innovative modification to an SBR wastewater treatment system to maximize enhanced biological phosphorus removal (EBPR) and biological nitrogen removal (BNR). The objective of the Phase I research was to demonstrate the concept using a pilot-scale reactor. The key objective of the Phase II research was to demonstrate the effectiveness of the technology by incorporating the process innovations into a full-scale upgrade to the existing SBR system at the Peshastin, WA Wastewater Treatment Plant (WWTP). Another objective of the Phase II research was to determine the rate and concentration of phosphorus (P) which can be released from thickened EBPR mixed liquor under anaerobic (fermentation) conditions and aerobic conditions such as in an aerobic digester to determine the feasibility of recovering P in the form of struvite for use as fertilizer.
Summary/Accomplishments (Outputs/Outcomes):
The key research work activity of the Phase II SBIR project involved the full-scale application of the innovative technology demonstrated in Phase I into the Peshastin, WA wastewater treatment plant (WWTP) which is owned and operated by Chelan County PUD. During the first year of the SBIR Phase II project, we worked closely with the Chelan PUD and their consulting engineer to coordinate the implementation of our process technology into the design drawings and specifications. In the first year, we also conducted pilot testing of a ceramic membrane thickening unit. The results of this pilot testing were used in developing the design of a full-scale thickener which was incorporated into the project for thickening of waste activated sludge withdrawn from the surface of the SBR tanks. Once the construction of the upgrade to the Peshastin SBR was complete, research conducted included monitoring process start-up and control system implementation and then process monitoring and optimization. Phase II Option research included investigation of phosphorus release in fermentation and aerobic digester pilot-scale reactors.
Conclusions:
The Phase II research findings demonstrated excellent results from the SBR design modifications implemented at the Peshastin WWTP. Consistent EBPR was achieved over a wide range of influent flow and loading condition with total phosphorus discharged from the SBRs as low as 0.2 mg/L. The settling properties of the EBPR mixed liquor was very good with the sludge volume indices (SVIs) usually in the range of 40 to 60 mL/gram. Phosphorus release occurred at rates and concentration under both fermentation conditions and aerobic digestion to make struvite recovery technically feasible, however it is not likely to be economically feasible at small WWTPs compared to other options such as composting or drying.
Verification of the research findings was based on chemical analyses for phosphate and nitrogen species in the SBR tanks while in operation and in the treated effluent from the treatment plant after implementation of the upgrade. Verification of the research findings was also accomplished through physical observations using a standard 2-liter settleometer, a phase-contrast light microscope and a stereo microscope with a dark field adapter. Online measurements of ORP, pH, and dissolved oxygen in the SBRs were also used.
The innovative SBR upgrade modifications demonstrated in this project are a cost-effective energy efficient solution for municipal and industrial wastewater treatment facilities for the removal of phosphorus and nitrogen in an environmentally sustainable manner and will facilitate the recovery of phosphorus for reuse in agricultural production. It will be applicable to a wide range of operational scales, however, the market where the technology that we have developed is most urgently needed is made up of the smaller communities which often lack the technical, financial, and managerial capacity to operate and maintain the complex wastewater treatment facilities needed to achieve increasingly stringent regulatory effluent limits for phosphorus and nitrogen.
SBIR Phase I:
Phosphorus recovery and high efficiency biological nutrient removal from wastewater with an innovative aerobic granular sludge sequencing batch reactor process | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.