Re ECF Project: ECF 2016-40

Project Title: Development of an novel energy-efficient nitrogen removal technology: A techno-economic assessment of treating food waste digestate

Applicant: Dr. Po-heng LEE, Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University

Total Approved Grant: $1,452,082.83

Duration: 1/4/2017 to 30/9/2018

Project Status/Remarks: On-going

This project aims to develop an innovative energy efficient nitrogen removal biotechnology for food waste valorization so as to support the Organic Waste Treatment Facilities (OWTFs) and other food waste and sludge co-digestion facilities led by the Government for food waste upcycle. Excess amount of high strength nitrogen digestate is expected, since Hong Kong government has decided to implement organic conversion into energy or valuable chemicals. Discharging these ammonium-rich digestate or concentrate directly into water bodies without advanced treatment, it causes eutrophication, hypoxia, harmful algal blooms, and greenhouse gas emission. Additionally, this low biodegradable chemical oxygen demand to nitrogen (bCOD/N) trait wastewater makes the traditional nitrification-denitrification as an significant energy consumer and sludge producer for nitrogen removal. A more energy efficient process to this end is anaerobic ammonium oxidation (anammox). The focus of this study is to:

1. establish a high-efficiency anammox process with ammonium-rich digestate or concentrate collected form a local food waste digestion facility;

2. devise downstream high-throughput residue/wastewater treatment for private and public food waste digestion facilities to complete sustainable process flow;

3. provide quantitatively holistic evidence for justifying the environmental benefits and economic viability of the developed technology using a holistic techno-economic assessment.

Summary of the Findings/Outcomes:
To be available upon completion of the project