Tertiary Phosphorus Removal Hampton Roads Sanitation District (HRSD) Virginia Initiative Plant (VIP): Technology Selection and Operational Considerations

Excess phosphorus and nitrogen released in treated wastewater can harm rivers and coastal ecosystems by promoting algal blooms and reducing water quality. Beginning in 2032, the Hampton Roads Sanitation District (HRSD) must meet a much stricter limit for phosphorus in treated wastewater at its Virginia Initiative Process (VIP) facility. This change requires both improvements to existing biological treatment and the addition of advanced treatment steps to remove the remaining nutrients before discharge. To identify effective solutions, HRSD tested two different treatment technologies that remove phosphorus using chemicals and physical separation. Both approaches successfully met the new phosphorus limit, but one option, the cloth media filtration system, required fewer chemicals and eliminated the need for an additional additive, making it simpler to operate. However, this system produced more return flows to the plant, which could increase hydraulic demands during certain operating conditions. In parallel, this research evaluated ways to improve nitrogen removal reliability by upgrading an existing treatment process that protects beneficial bacteria from toxic cyanide. A pilot system using attached-growth microorganisms was tested and showed strong performance even under high loading, elevated temperatures, and after operational disturbances. The system recovered quickly and exceeded design expectations. Overall, this study demonstrates practical, scalable strategies to help HRSD meet future nutrient limits while minimizing new construction, reducing chemical use, and improving treatment reliability. The results provide guidance for selecting technologies that protect water quality while maintaining efficient and resilient wastewater treatment operations.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Civil Engineering

Department dc:contributor.department

Civil and Environmental Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2026

Author dc:creator

• Blair, Aidan Wallace

Chairs dc:contributor.committeechair

• Pruden-Bagchi, Amy Jill
• Bott, Charles B.

Committee member dc:contributor.committeemember

• Knocke, William R.

• chemical phosphorus removal
• cloth media filtration
• precipitation
• ballasted sedimentation
• moving bed biofilm reactor

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

vt_gsexam:45634

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/140810