1	UPGRADING EXISTING PLANTS FOR NUTRIENT REMOVAL September 2007 COPYRIGHT 2007 EEMA INC. – ALL RIGHTS RESERVED
2	Nutrients of Concern: Nitrogen Phosphorus
3	Forms of Nitrogen: Ammonia (NH₃) Organically Bound Nitrogen Nitrite (NO₂) + Nitrate (NO₃)
4	Forms of Phosphorus: Phosphate (PO₄) Organically Bound Phosphorus
5	Bacteria Cell: 11.5-16% by Wt. Nitrogen 2.5-3% by Wt. Phosphorus Both nutrients are organically bound.
6	Nitrogen Removal two biological processes: Nitrification NH₃ → NO₃ Denitrification NO₃ → N₂ + O₂
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8	Nitrification Requirements: Adequate Detention Time Adequate Biomass 7.2 mg/L Alkalinity/mg/L NH₃ +100 mg/L effluent Alkalinity 4.6 mg/L Dissolved Oxygen/mg/L NH₃ Temperature above 55°F in Mixed Liquor
9	Denitrification Requirements: Adequate Detention Time Essentially zero Dissolved Oxygen May need Carbon Source
10	Domestic Sewage: BOD 200-250 mg/L Organic N 20 mg/L Ammonia 20 mg/L Total Kjeldahl (TKN) 40 mg/L
11	Phosphorus: BOD 200-250 mg/L Total Phosphorus 6-8 mg/L
12	Biological Treatment Nutrient Requirements 100 mg/L BOD 5 mg/L N as NH₃ 1 mg/L P as PO₄
13	In Pennsylvania Design for full nutrient removal Nitrogen removal is biological Phosphorus is chemical
14	Design is Dependent on Effluent Requirements
15	Nitrification Design Minimum Single Stage Nitrification in Pennsylvania 12 hours
16	De-Nitrification
17	De-Nitrification
18	Front End Anoxic Zone Appropriate Anoxic defined as NO₃ present, but no free O₂.
19	Front End Anoxic Returns Approximately 3.6 parts of Alkalinity of the 7.2 parts required for Nitrification. and 2.6 parts of Oxygen of the 4.6 parts required.
20	Internal Recycle 1:1 reduces NO₃ by 50% 2:1 reduces NO₃ by 67% 3:1 reduces NO₃ by 75%
21	Front End Anaerobic and Anoxic Zones
22	Anaerobic Zone Anaerobic zone defined as no free O₂ and no free NO₃. Solubilizes Phosphorus for easier biological and chemical removal. Stabilizes process biology.
23	"After front end zones reduce..." After front end zones reduce NO₃ by 82%. Leaving 18-50% of NO₃ remaining. At 16-20 mg/L NO₃ in municipal effluent, this leaves 3-10 mg/L NO₃ remaining.
24	"This is best handled by..." This is best handled by a back end anoxic zone.
25	Clarification: Range 20% to 40% larger. SVI = Sludge Volume Index SVI BOD removal 80-100 SVI Nitrification 100-130 Nitrified sludge does not settle or thicken as well as non-nitrified sludge.
26	Phosphorus Removal Biological to 1.0 mg/L. Must have 10 mg/L soluble BOD to 1 mg/L Phosphorus. Biological P removal is totally aerobic. If mixed liquor or sludge goes without free oxygen, Phosphorus will release.
27	Phosphorus Removal Chemical addition Alum Ferric Chloride Ferric Chloride not compatible with UV light disinfection. Dosages are not based on pure chemistry – many side reactions.
28	Phosphorus Removal Chemical addition points: To final clarifier Onto filters dosages dependent on effluent requirements Filters required below 0.5 mg/L P final effluent requirement and recommended below 1.0 mg/L
29	Filters Should be deep bed for denitrification to polish effluent. Carbon source maybe required – standard is Methanol – unsafe use Potassium acetate. Dosage controlled of effluent requirements.