NJDEPs New Phosphorus Policy: A Treatment Plant Perspective

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NJDEPs New Phosphorus Policy A Treatment
Plant Perspective
Presented at Phosphorus and the Land A
symposium for the agricultural, environmental,
and academic communities, and policymakers Prese
nted by James F. Cosgrove, Jr., P.E. TRC Omni
Environmental Corporation JCosgrove_at_TRCsolutions.c
om
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The New Phosphorus Policy

• If stream phosphorus exceeds 0.1 mg/l, set
  effluent limit at 0.1 mg/l.
• OR
• Complete a study to demonstrate that phosphorus
  is not limiting and is not rendering the waters
  unsuitable for the designated uses.
• AND
• Deal with time consuming TMDL later

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Is Phosphorus Removal Necessary and Appropriate?

• Is stream concentration above 0.1 mg/l standard?
• Is STP increasing stream concentration?
• Is there an impact that could be created by
  phosphorus?
• If yes, is the impact caused by phosphorus?
• Is a reduction of phosphorus going to translate
  to environmental benefit?

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Indicators of Eutrophication

• Excessive algae
• Excessive Rooted Plants (macrophytes)
• High Chlorophyll-A concentrations
• Excessive Diurnal Dissolved Oxygen Swings
• Dissolved Oxygen Instream Standard Violations (4
  mg/l FW2-NT, 5 mg/l FW2-TM, 7mg/l FW2-TP)

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Physical Constraints to Eutrophication

• Stream substrate (e.g., rock prevents rooted
  macrophytes)
• Stream velocity and depth
• Light / Turbidity / Shading

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The Limiting Nutrient Concept

• Nutrients serve as fertilizer to algae /
  plants. If excessive nutrients are present, they
  will not limit plant growth. However, if a
  particular nutrient is at a very low
  concentration, it may limit plant growth.

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Purpose of NJDEP Phosphorus Study(Under
Development)
Provide technical guidance for simplified
study to demonstrate whether or not TP is the
limiting nutrient AND whether or not TP otherwise
renders the waters unsuitable for the designated
uses.
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Phosphorus Study Elements
0.1 mg/l TP limit and optional study in permit
Is any portion of the spatial extent considered a
tributary to a lake / impoundment / intake
YES
Define spatial extent
NO
Collect instream data
Is 0.05 mg/l TP criterion exceeded at point in
segment where it applies?
NO
YES
YES
Is P limiting?
Effluent TP limit based on 0.1 mg/l criterion or
site-specific nutrient criteria
NO
Possible wasteload allocation through TMDL
Are waters unsuitable due to phosphorus?
YES
NO criterion does not apply
No effluent TP limit based on 0.1 mg/l criterion
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Monitoring Program

• Sampling Locations
• Minimum of 3 Stations
• One at upstream end of segment
• One below discharge
• One at downstream end of segment
• Other Potential Stations
• At lake / impoundment / intake
• Other intermediate locations

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Monitoring Program

• Parameters
• Dissolved Oxygen (DO)
• Algae
• Periphyton (attached) Chlorophyll-a
• Phytoplankton (suspended) Chlorophyll-a
• Phosphorus (total and dissolved reactive)
• Nitrogen (ammonia, TKN, nitrate nitrite)
• Turbidity
• Total Suspended Solids (TSS)
• Total Recoverable Iron (Fe)
• Stream Flow (Q)

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Monitoring Program

• Monitoring Period/Frequency
• DO, nutrients, Chl a, turbidity, TSS, Fe
• 20 low flow events from June 1 Sept 30
• Diurnal DO, temperature, pH, Turbidity, Q
• 3 low flow events of 3 days each from June 1
  Sept 30
• Algae
• 4 events with triplicate samples to yield 12
  samples per location

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Is TP limiting?
Is Dissolved Reactive Phosphorus gt 0.05
mg/l? OR Is Total Inorganic Phosphorus
lt 5 ? Dissolved Reactive
Phosphorus If Yes to either question, phosphorus
not limiting
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Are Designated Uses Impaired?

• Diurnal Dissolved Oxygen
• Is daytime average 3 mg/l higher than nighttime
  average?
• Is minimum instream DO criterion violated in
  greater than 10 of the samples?
• Is daily average instream DO criterion violated?
• If 1 and 2 or 1 and 3 are true, eutrophication
  impacting designated useif TP is limiting, set
  STP limit.

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Are Designated Uses Impaired?

• Periphyton Concentration (attached algae)
• Is Seasonal Mean gt 150 mg/sq.m
• OR
• Is Individual Sample gt 200 mg/sq. m
• Phytoplankton Concentration (suspended algae)
• Is Seasonal Mean gt 24 ug/l
• OR
• Is Individual Sample gt 32 ug/l
• If any of these are true, eutrophication
  impacting designated use if TP limiting, set STP
  limit.

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Areas Requiring Further Thought

• Must provide for site-specific criteria or
  watershed-based option for lakes, impoundments,
  or intakes.
• If eutrophication found, but TP not limiting, a
  0.1 mg/l effluent limit should not automatically
  be set.
• Intricacies of instream monitoring
• The reality of pollutant trading

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Case Study 1 Pollutant Trading
A False Hope
STP Flow 20 mgd Effluent TP 3 mg/l Upgrade
to get effluent to 0.5 mg/l.
Resulting Point Source Load needed to be removed
24,000 lbs/year
Watershed Area 500 mi2 NPS TP Loading Rate
0.3 lbs/acre/yr
96,000 lbs/year
PROBLEM
Even if treatment technology installed to provide
0.5 mg/l effluent, would need to remove 25 of
NPS Load in entire watershed to trade!
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Case Study 2 Pollutant Trading
A False Hope
STP Flow 2 mgd Effluent TP 1 mg/l New Permit
requires TPlt0.1
Resulting Point Source Load needed to be removed
5,500 lbs/year
Watershed Area 50 mi2 NPS TP Loading Rate
0.3 lbs/acre/yr
9,600 lbs/year
PROBLEM
Would need to remove 57 of NPS Load in entire
watershed to trade! BMPs are not THAT good!
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Case Study 3 Hightstown East Windsor MUA
Facility Upgrades

• Both STPs added phosphorus removal in early
  1990s
• Average discharge TP reduced from 2 - 4 mg/l to
  0.3 - 0.5 mg/l
• Average downstream TP reduced from 0.2 to 0.1
  mg/l from 1991 to 1997
• Excessive eutrophication occurs downstream
• Groundwater in vicinity of Millstone River found
  to be extremely high in TP. USGS estimates that
  the vast majority of TP load in the Millstone
  River downstream of STPs is from groundwater!
• Was the money well spent? Would eutrophication
  impacts be reduced if STPs further reduced TP
  load, or are NPS reductions necessary?

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Questions
???