high value resources from high strength wastes: leveraging ......chesapeake wea | plant operations...

High Value Resources from High Strength Wastes: Leveraging Food

Production Byproducts to Reduce BNR Costs

June 12, 2015 | Washington Suburban Sanitary Commission | Laurel, MD Chesapeake WEA | Plant Operations and Maintenance Committee’s Educational Seminar

Christopher Wilson, Ph.D., P.E. Edward Cronin, P.E. Greeley and Hansen

Today’s Presentation discusses an innovative approach to procuring alternative carbon resources • Nutrient Reduction Program at City of Richmond WWTP

– Treatment requirements – Inherent nitrogen removal flexibility

• Opportunities presented by industrial products – Public Utilities as a catalyst for economic development – Screening of potential brewery byproducts of value

• The current process: – Product receiving and feeding implementation – Understanding holistic product value – Turning assigned value into a commodity product

Richmond WWTP Service Area

Separate Sewer System Tributary to Richmond WWTP Separate Sewer System Tributary to Counties Combined Sewer System Tributary to Richmond WWTP

Chesterfield County

Henrico County

Henrico County

Richmond City Limits

Legend

James River

Powhatan County

Goochland County

Richmond WWTP

Disinf.

WWF = 75 MGD DWF = 45 MGD

Effluent Filters

75 mgd

Storage Tank

Aeration Tanks

Primary Sed Tanks

Final Sed Tanks

Degritter

Class B Land App

Anaerobic Digestion Gravity

Thickening

Interceptors (Combined Sewer System)

Effluent

Primary Screening and Grit Chamber

Main Pump Station

Secondary Screening

WAS Centrifuge Thickening

Pre-Upgrade Process Diagram 45 MGD Dry / 75 MGD Wet Weather Capacity

Nutrient Reduction Program Reliably Meet TN/TP Discharge Requirements

Note from General Permit Registration List Regarding Reporting: “Waste load allocations for localities served by combined sewers are based on dry weather design flow capacity. Reported discharge loads for the Richmond WWTP shall include the loads associated with the first 45 MGD of flow on each day.”

New Water Quality Standards are in effect as of January 1, 2011

Dry Weather Flow Capacity

(MGD)

Total Nitrogen WLA Total Phosphorus WLA

WLA Based on Conc

mg/L

Yearly Load lbs/yr

WLA Based on Conc

mg/L

Yearly Load lbs/yr

45 8.0 1,096,402 0.50 68,525

UV

WWF = 75 MGD DWF = 45 MGD

Effluent Filters

75 MGD

Storage Tank

Aeration Tanks

Primary Sed Tanks

Final Sed Tanks

Degritter

Class B Land App

Anaerobic Digestion Gravity

Thickening

Interceptors (Combined Sewer System)

Effluent

Primary Screening and Grit Chamber

Main Pump Station

Secondary Screening

WAS Centrifuge Thickening

Post-Nutrient Upgrade Process Diagram

Denitrification Filters

Chemical Phosphorus Removal

UV Disinfection

Secondary Treatment Reliability Upgrades

Primary Solids Fermentation (Carbon Recovery)

Sidestream Treatment (TN Management)

Centrate Sidestream Treatment

Methanol

Fermenter

Influent ammonia loading had been relatively stable from 1992 to 2005

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016

NH4 Average Daily Load by Month 12 per. Mov. Avg. (NH4 Average Daily Load by Month)

Influent Average Daily NH3-N Loading (lb/day)

Since 2005, influent ammonia loading has Increased significantly - by more than 100%

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016

NH4 Average Daily Load by Month 12 per. Mov. Avg. (NH4 Average Daily Load by Month)

Influent Average Daily NH3-N Loading (lb/day)

More Nitrogen Loading = More Methanol Demand

($1.6M in 2014)

Three Flexible Nitrogen Removal Facilities

Sidestream Treatment

Primary Sed. Tanks

Aeration Tanks

Gravity Thickening Tanks

Thickening Bldg.

Digestion Tanks

Grit Chamber No. 2

Scum Control

Final Sed. Tanks 1-6

Sludge Dewatering

Admin. Bldg.

Grit Chamber No. 1

Main Pumping Station

Methanol Bldg.

Supplemental Pumping Station

Sludge Storage

Re-Aeration Tank

To Outfall

UV Effluent Filters

Final Sed. Tanks 7-8

IMLR Pumps (MLE)

Fermenter

Aeration Tanks and Sidestream Treatment are Flexible to use Alternative Carbon

Filters Require Methanol

• Richmond, VA competitively selected – 40 cities, 3 finalists

• 500,000 barrel per year production • Destination Restaurant • 288 Jobs • $74M Capital Investment • $1.2M/year tax revenue

Stone Brewery & Restaurant Development

Site

City of Richmond WWTP

Inherent flexibility facilitated opportunities for the WWTP and the City

Mixing evaluation of high-rate fermenter

Identification of brewery waste product – leveraged value to WWTP to attract industry to the City

Brewery selected Richmond VA, in part because of partnership opportunity with public utilities

Initial primary sludge fermentation design adaptable to future high strength wastes

Three waste streams were screened for their applicability as products at WWTP

• City reviewed value of 3 by-products of large scale beer production: – Brewery Process Wastewater (low strength, sewered) – ‘LT DRIP’ Lauter Tun drainage (high strength, trucked) – Spent Yeast (very high strength, trucked)

The brewing process creates several distinct waste streams that were evaluated

Brewery Process Wastewater

Lauter Tun Drainage (LTD)

Spent Yeast

Rapid screening of brewery products revealed the value proposition of each product

Carbon Product Recovery Economic /Process Model

HSW Character

Sludge Character

Process Stoichiometry

Energy/Commodity Data

Energy Product

Commodity Product

Biosolids Impacts

BNR Impacts

Capital Facility Req’s

Σ = Descriptive life cycle

economics and external fee requirements

Background of brewery product evaluation for use at Richmond WWTP

• City reviewed value of 3 by-products of large scale beer production: – Brewery Process Wastewater (low strength, sewered) – ‘LT DRIP’ Lauter Tun waste (high strength, trucked) – Spent Yeast (very high strength, trucked)

• Outcomes of product screening, City will… – Receive brewery process wastewater

Industrial discharge to sewer, received with raw influent Subject to high strength waste surcharges

– Not accept spent yeast Too high pCOD Impacted biosolids more than corresponding value

– Procure lauter tun drainage based on net methanol offset value Focus for remainder of presentation

Variable characteristics of Lauter Tun Drainage; consistently high sCOD content

Parameter Unit

Individual Grab Sample Analyses

Barley Wine IPA IPA IPA Session

IPA

Total Kjeldahl Nitrogen mg N/L 1,000 1,700 1,920 585 540 Phosphorus, Total mg P/L 300 300 441 76 22

Total Suspended Solids mg TSS/L 44,000 20,000 21,800 53,122 13,000 Volatile Suspended Solids mg VSS/L - 20,730 50,878 -

Chemical Oxygen Demand mg COD/L 140,000 100,000 139,350 190,600 95000

Soluble Chemical Oxygen Demand

mg COD/L - 93,000 100,850 120,300 -

Biochemical Oxygen Demand mg BOD/L 47,000 54,000 61,800 - 48,000

Soluble Biochemical Oxygen Demand

mg BOD/L 43,000 50,000 52,033 - 39,000

pH NA 5.40 5.47 5.40 5.70 5.55

Soluble and Particulate COD will behave differently in the WWTP & have differing values • Soluble Sugars

– Readily fermentatable – Directly elutriated if not fermented

• Soluble Complex – Fermentable – Directly elutriated if not fermented

• Particulate Solids – Limited conversion in fermenter – Mostly degraded in anaerobic digester

LTD

LTD

Lauter Tun Drainage (Brewery Byproduct) Discharge Point

Alternate Lauter Tun Drainage (Brewery Byproduct) Discharge Point

LEGEND

Primary Clarifier

Fermenter

Dewatering

Aeration Tank

Methanol Dose Point

Gravity Thickener

Side Stream Treatment

Anaerobic Digesters

RAS

tWAS

HS

HMS tPS

rbCOD (GTO)

LTD LTD

LTD

WAS Thickening

Secondary Clarifier

Deep Bed

Filters

Methanol Dose Point

Alternate

Alternate

to GTO

DS FS

Soluble and Particulate COD will behave differently in the WWTP & have differing values • Soluble Sugars

– Readily fermentatable – Directly elutriated if not fermented

• Soluble Complex – Fermentable – Directly elutriated if not fermented

• Particulate Solids – Limited conversion in fermenter – Mostly degraded in anaerobic digester

Elutriation is the primary mode of recovery for soluble COD.

Assumed 85% recovery of sCOD based on overflow/underflow ratio of gravity thickeners

12% conversion to sCOD in fermenter, remainder (up to VSR limit) degraded in digester

Operational decisions can greatly impact the gross value of recovered resources

$0.0$0.2$0.4$0.6$0.8$1.0$1.2$1.4$1.6$1.8

All Biogas - NoHSW

Fermentation - NoHSW

All Biogas -w/HSW

Fermentation -w/HSW (12%

pCODconversion)

Fermentation -w/HSW (20%

pCODconversion)Supplemental Carbon Value

Biogas Energy Value

Gross Value of Recovered Resources ($US/year)

Example: Conventional Co-digestion Spent Brewers Yeast Assessment

$0.099/ gallon

$0.059/ gallon

$0.049/ gallon

-$ 100k

-$ 80k

-$ 60k

-$ 40k

-$ 20k

$ k

$ 20k

$ 40k

$ 60k

$ 80k

0.72 DT/day 2.16 DT/day 4.32 DT/day

Increased Digester Gas Energy Recovery

Increased Biosolids Management

Increased Ammonia in Side Stream

Annualized Receiving Station

Annualized CHP Facilities

Net Value of Codigestion

Required Gate Fee to Break Even (assuming 2-3% TS)

(No gate fee)

Remember: Richmond’s goal is to develop net value from brewery product receipt to justify purchasing as commodity chemical

Annu

al P

rodu

ct V

alue

-$ 1000k

-$ 500k

$ k

$ 500k

$ 1000k

$ 1500k

$ 2000k

7.207128457

Increased Methanol Recovery

Increased Digester Gas Energy

Increased Ammonia in Side Stream

Increased Biosolids Production

Facility Improvements

Net Value

$0.49/gallon Value to be leveraged (gain share) to purchase as commodity chemical

Example: 80% HSW VSR in digester

Product value tied to MeOH

Example: Co-fermentation to recover rbCOD Lauter Tun Drainage Evaluation

7.21 DT/day

(No gate fee)

Annu

al P

rodu

ct V

alue

In summary, recovery of high value products enhances resource recovery opportunities • The Conceptual Utility of the Future considers the holistic value

of resources and waste streams – Identification of holistic value allowed Richmond to justify purchase of

waste product – Partial cost reduction for supplemental carbon – Contributed to large economic win for the City by attracting large

industrial facility

In summary, recovery of high value products enhances resource recovery opportunities • The intrinsic flexibility of the WWTP allowed the City to take

advantage of the highest value opportunity – Multiple ways to remove nitrogen – No sunk cost in energy recovery actually helped justify recovery of higher

value (per BTU) products, e.g. VFA

• If we believe in recovering and reusing resources contained in environmental waste streams then seeking and developing strategies to extracted higher value products is critical – Entrepreneurialism that benefits served communities is a key

aspect of the Utility of the Future!!!

THANK YOU

Chris Wilson, Ph.D., P.E. Associate, Residuals Practice Leader Greeley and Hansen [email protected]

high value resources from high strength wastes: leveraging ......chesapeake wea | plant operations...

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