[PPT] - Membrane Bioreactor vs. Extended Aeration Treatment Pilot Study PowerPoint Presentation

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Innovative Solutions for Water and the Environment

Membrane Bioreactor vs. Extended Aeration Treatment Pilot Study – Effluent and Groundwater Quality

Presenter

Leslie Dumas September 15, 2009

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Acknowledgements

Thanks to: Colin Moy, REA., East Bay Municipal Utility District [EBMUD] – Project Manager Eileen Fanelli, P.G., East Bay Municipal Utility District/Presidio Trust – Project Manager David W. Smith, Ph.D., Merritt Smith Consulting – Principal Investigator

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Background

WateReuse Foundation Project WRF-04-016
Project Title: Development of Regulatory

Protocol for Incidental Environmental Reuse of Title 22 Recycled Water

Issued August 2005 to EBMUD with RMC Water &

Environment

EBMUD’s ‘upcountry’ wastewater systems needs:
Upgrading systems to meet evolving regulatory requirements
Beneficial reuse of treated effluent
Use of small MBR treatment systems

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The Pardee Site

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Key Challenges to Recycling in California

Regulatory Compliance - Resolution #68-16

Antidegradation Policy

Cost-Benefit for Small Systems
Higher capital cost to implement MBR treatment
Little to no reduction in longer-term operating costs
Permitting costs increase overall capital costs

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Study Goals

Recognize baseline assumptions on meeting

CCR Title 22 standards for unrestricted use

Provide a standardized process (Framework) for

evaluating recycled water projects

Utilize established and industry-accepted tools

and practices for assessment

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A Two-Part Study Approach was Used

Develop a Framework (standardized process)
Conduct a Pilot Test

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Pilot Study Design

Conducted over 12 month period
Sampled and analyze influent, effluent and

groundwater quality from both existing and pilot systems

Apply data to Framework analysis
Identify key operating differences between the

extended aeration and MBR treatment plants

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Treatment Trains

Pilot MBR Plant Schematic PACT Extended Aeration Plant Schematic

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Conventional Plant

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Pilot Plant

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Pilot Plant

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Pilot Plant

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Pilot Plant

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Pilot Plant

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Pilot Program Analytical Plan

Parameter Influent Effluent Groundwater Settleable Solids (SS)  Total Suspended Solids (TSS)  pH    Dissolved Oxygen  Total Dissolved Solids (TDS)   Turbidity  Biological Oxygen Demand (BOD5)   Chemical Oxygen Demand (COD)   Total Organic Carbon (TOC)    Total Kjeldahl Nitrogen (TKN)    Ammonia (NH3 - N)    Nitrate (NO3 – N)   Total Coliform Bacteria (after disinfection)   Viruses (after disinfection)  General Minerals    Metals   Trihalomethanes (THMs)   Halogenic Acetic Acids (HAAs)   n-Nitrosodimethylamine (NDMA)  

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Influent W ater Quality Analysis

Influent quality was consistent throughout the

pilot study

Influent from PACT is found to be consistent with

a low-strength municipal wastewater

Constituent concentrations appear to be on the

same order of magnitude for both pre- and pilot- period influent data based on a trend analysis.

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Effluent W ater Quality Analysis

1. Confirm the assumption that the MBR effluent

met disinfected tertiary-treatment criteria

2. Identify the main differences in effluent quality

produced by the extended aeration and the MBR pilot systems

3. Compare to groundwater quality over the pilot

study period

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Comparison of Expected and Actual MBR Effluent Quality

Parameter Units Published Expected Effluent Value Pilot MBR Effluent Quality Average Range BOD5 mg/L < 5 1.2 ND (< 2) - 2.2 TSS mg/L < 1 Not Sampled Not Sampled Ammonia mg/L as N < 1 0.63 ND (<0.3) - 6.72 Nitrate mg/L as N NA 30.03 0.19 – 53 Total Kjeldahl Nitrogen (TKN) mg/L as N NA 1.58 ND (< 1) – 11 Nitrite mg/L as N NA 0.16 ND (<0.0035) – 0.44 Total Nitrogen mg/L as N < 3 32.40* 0.19 – 71.16* Total Phosphorous (measured as Orthophosphate as P) mg/L < 0.2 6.8 1.7 - 9.9 Turbidity NTU < 0.2 0.34 0.13 – 1 Bacteria (measures as Total Coliform) Log removal Up to 6 log (99.9999%) 23.3 ND (< 2) – 230 Viruses Log removal Up to 3 log (99.9%) ND ND

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MBR Effluent W ater Quality Analysis

Results
Improved for clarity, aluminum removal

and BOD degradation

No difference for nitrogen, phosphates,

total dissolved solids and most metals

Reduction in lead, manganese, and
rthophosphate
Poor denitrification (no change in TKN,

ammonia and nitrate concentrations)

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Groundwater W ater Quality Analysis

Water quality analyzed to:
characterize groundwater quality for both the pre- and

MBR pilot periods

Identify statistical differences that could be

attributable to the MBR pilot system

The aquifer underlying the effluent pond is

composed fractured bedrock

Used major ionic species to ‘fingerprint’ the

water quality

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Piper Diagram shows no difference between pilot and pre-pilot groundwater quality

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Similar shaped Stiff Diagrams support the same conclusion

Pre-Pilot Data Pilot Data

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Groundwater Quality Results did not Reflect Change in Effluent Quality

Few anomalies observed, but longer

monitoring required to determine cause

Pre- and pilot effluent qualities are

significantly different from groundwater

No changes in groundwater quality may

be result of:

slight change in effluent chemistry
low volumes of effluent discharged to

pond

short monitoring period

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Study Conclusions

MBR system produced generally better effluent
MBR system was efficient in biodegradable and
rganic compounds removal
MBR was not efficient in phosphorus removal or

denitrification

Groundwater does not appear to be impacted by

either pre-pilot or pilot data over the monitoring period Based on testing, not reasonable to upgrade plant to achieve improved environmental results

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The Framework was Tested with Pilot Data

Highlighted need for

thorough data collection

Demonstrated

flexibility needed in developing the reuse scenario

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The Full Report

A Protocol for Estimating Potential Water Quality

Impacts of Recycled Water Projects: Final Report and Pilot Test Results; WateReuse Foundation: Alexandria, VA. 2009.

A Protocol for Estimating Potential Water Quality

Impacts of Recycled Water Projects: Framework and User Guidance; WateReuse Foundation: Alexandria ,VA. 2009.

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QUESTIONS?

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Framework Design

Internally consistent process
Early disclosure of potential impact
Allow project refinement to address possible

impacts

Rely on established analytical tools and

accepted industry practices

Apply on a constituent basis
Broadly applicable
Scalable relative to both project size and

number of constituents of potential concern

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Framework Analysis Process

Consists of two main elements

Preliminary Screening
Detailed Site Evaluation

Figure 1 – Framework Analysis Process Figure 1 – Framework Analysis Process

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Preliminary Screening

 Process

 Step 1 –Water Quantity Analysis  Step 2 –General Water Quality Analysis  Step 3 – Screen Applicable Guidelines and Regulations

 Assumptions

 Meets criteria for disinfected tertiary recycled water  Beneficial reuse for irrigation at agronomic rates  Storage not in a water of the United States

 Outcomes

 Identification of constituents of potential concern  Identification of applicable water quality goals and objectives  Identification of site-specific parameters for detailed analysis

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Detailed Site Analysis

 Process

 Step 4 –Prepare site assessment focused on vegetation,

soil geochemistry and soil hydraulics

 Step 5 –Complete the constituent analysis

 Assumptions

 Rely on site-specific data or literature values ,as

appropriate

 Outcomes

 Refine list of potential constituents of concern  Estimate short and long term magnitude of potential impact  Identify options for mitigating potential impacts