Session: 18-01-04: Sustainability in Industry

Paper Number: 143006

143006 - Nitrogen and Phosphorous Removal via Anaerobic / Anoxic & Aerobic Processes and Struvite Formation in Mall Wastewater: Performance of Retrofitted Full-Scale Plants 

Nitrogen is essential for life. It is the fourth most abundant element in the biosphere. Domestic wastewater such as those coming from shopping malls contains high concentrations of plant nutrients nitrogen and phosphorous (N & P), and therefore, brings high nutrient load to receiving bodies of water. These nutrients are key factors that cause eutrophication of closed water system and excessive growth of algae. Wastewater treatment plants must remove phosphorous and nitrogen compounds from wastewater before its final disposal in order to prevent eutrophication. With the strict implementation of the Department of Environment and Natural Resources (DENR) of the Philippine Clean Water Act, otherwise known as Republic Act 9275, about nitrogen content of effluent and other pollutants, new and more sustainable wastewater processes must be explored and developed.

With the new standards on nitrogen (N) and phosphorous (P) in wastewater discharges from industrial, commercial and municipal wastewater, there is a need for better wastewater treatment system. Moreover, with the presence of such N and P in wastewater, struvite formation leading to clogging of pipes has also been a problem in wastewater treatment system. This study aimed to improve N and P removal from mall wastewater through retrofitting with the inclusion of anaerobic/anoxic process prior to existing aerobic process and recirculation of part of the effluent from aerobic process to anoxic tank in order to achieve ammonification or organic nitrogen, nitrification and denitrification in the whole system. The recovery of magnesium ammonium phosphate (MgNH4PO4), which is commonly called struvite, is expected to be another pathway via which N and P can be removed from the wastewater. Several mall wastewater treatment plants were retrofitted following a bench-scale study and their effluents were monitored. Both the previous and new system include chlorination as a final treatment. The treatment performance with respect to the removal of N and P of the new retrofitted system is better than the system where the biological treatment process was mainly aerobic. Better levels of organic matter, oil and grease, total suspended solids (TSS), surfactant and fecal coliform were also achieved. In the first step, an anaerobic/anoxic process, relatively large amounts of organic N is converted to ammonia, which precipitated as struvite in the succeding mixing tank. The new wastewater treatment system, with reduced aeration requirements, where N and P were removed by nature based bacteria and without the use of large dose of chemicals becomes a cost-effective solution for a cleaner environment.

Keywords: anoxic, ammonia, denitrification, domestic wastewater, nitrification, mall wastewater, phosphate, struvite

 

Presenting Author: Ma. Cleofas Maceda Young Moon PH

Presenting Author Biography: Dr. Ma. Cleofas Oliver Maceda has over 30 years of experience in environmental engineering, pollution control and management, and sustainability, with both public and private sectors, in the following areas of competence:

- Pollution Control and Management
- Hazardous Waste and Management
- Soil Remediation
- Water and Wastewater Management, Design and Control, Operation and Maintenance
- Environmental Systems and Compliance
- Circular Economy
- Environmental Impact Assessment
- Environmental Risk Assessment

Dr Maceda graduated her BSME from the Divine Word University of Tacloban. She is a Licensed Professional Mechanical Engineer; she graduated of Master of Management in Business Management from the University of the Philippines Visayas Tacloban, Master of Science in Environmental Engineering from the University of the Philippines Diliman, Doctor of Philosophy in Environmental Engineering from the University of the Philippines Diliman.

Dr Maceda excelled as a natural leader who worked as an executive with over 20 years of experience in mechanical and environmental engineering and sustainability. Her latest endeavor were when she was the Head Corporate Pollution Control Officer at the Westpoint Industrial Mills Corp. from 2001 to 2007, and the Head Environmental Compliance of Robinsons Land Corporation – Commercial Center Division from 2007 to 2023; and works as Environmental and Sustainability Consultant for private and public sectors. She has shown outstanding performance and achievements in industry, research and service, and has contributed significantly to the development of environmental management and sustainability practices.

Authors:

Ma. Cleofas Maceda Young Moon PH