SFPUC Biosolids A resource we all help make Agenda Intros who is - - PowerPoint PPT Presentation

SFPUC Biosolids

A resource we all help make

• Intros – who is here and what are you hoping to get out of this?
• Transition to Resource Recovery
• Shifting the balance sheet
• Why is it necessary (solving real societal challenges)
• What role can we play as resource managers
• How does this new way of thinking change our operations?
• Focus on exceeding regulation and letting product quality be a driver
• Career implications and the need for new skills
• Questions and discussions

Agenda

Wastewater Basics

Fats, oils and grease Influent Contaminants of Emerging Concern Stormwater Effluent Biosolids GHG emissions

Inputs Outputs

Liabiliti ties

• Effluent
• Methane emissions
• Biosolids
• Nitrogen/Phosphorus

Shifting the Balance Sheet

Assets ts

• Recycled water
• Vehicle fuel / renewable gas
• Soil amendments / C seq.
• Fertilizers

4

Uniquely Suited to Address Big Issues

WWRFs RFs Water Energy Carbon

How Does This Impact Our Operations?

• Provide a Reliable, Resilient & Flexible System that

Respo ponds s to Catastroph strophic c Events nts

• Recove

covery ry Resources sources and Produce High Quality Products

• Maintain Ratepay

epayer er Afford fordabi abili lity ty

• Integrate Green & Grey Infrastructure to Manage

e Stormwa rmwater ter and Minimi mize ze Flood

• ding

ing

• Provide Benefi

efits ts to Local Communit mmunities ies

• Modify the System to Adapt

t to Climate ate Change nge SFPUC Capital Upgrades

Producing Soil Amendments

Biosoli solids ds are the nutrient nt-rich h soil amendm ndment nt that we produce in San Francisco from the wastewater treatment process

• Nitrogen, Phosphorus, Potassium, Sulfur, Calcium, etc.
• There is a finite amount of these nutrients in the soil

Soil Fertility – The Reason We Ate Yesterday

We greatly reduced limits on soil fertility with synthetic fertilizers

We are utterly dependent on inorganic fertilizer

• Microorganisms feed on wastewater solids, killing

pathogens and breaking down pollutants

• The process takes ~ 1 month at controlled

temperatures

• The result is biosolids that are rich in nutrients and
• rganic matter

Our Digesters Capture these Nutrients

• Inorganic fertilizers are elements

decoupled from carbon, leading to leaching and pollution

• SFPUC Biosolids are 60% carbon

compounds

Biosolids Not Only Return Nutrients to Soils…

• Slow release of N, P,

K, S, Ca, Mg, B, Cu, Mn, Fe, Mo, Zn, etc.

• Increases water

holding capacity

• Improves soil

structure

• Increases water

infiltration rate

• Decreases erosion
• Increases soil

microbial activity

• Increases nutrient

holding capacity

Benefit of Biosolids Applied to Soils

Portion of field without SFPUC biosolids Portion of field amended with SFPUC biosolids

Collapse in soil health has catastrophic environmental, social and political implications

We need to prepare for more extreme droughts

• Research has shown that drought in

California will become more severe due to climate change (Yoon and Gillies 2015; Swain et al. 2016)

• Biosolids and things like compost
• Increase water holding capacity
• Reduce the need for irrigation
• Stabilize soils against erosion

Biosolids can be used to repair ecosystems where soils have been destroyed

• One time

e applica ication tion of compost mpost to rangela eland nd soil l increa eases ses carbon bon storage rage 25-70% 70% (Ryals ls, , Silver er 2013) 13)

• Compo

post st resul ults ts in net greenh enhou

• use

se gas offsets fsets even when n taking ng into

• accou
• unt

nt transp sportation tation and other er emissio sions ns associa

• ciated

ted with comp mpos

• st

t (DeLonge Longe, , Ryals, , Silver er 2013) 13)

• Bioso

soli lids ds application cations s over r 22 years s result ults s in up to an addition ional al 160 metri ric c tons s carbon bon stored red per hectar tare e (Tian n et al. 2009) 9)

• Bioso

soli lids ds application cations s seque uester ster 3 times es more e carbon bon than n equival valen ent t applica ications tions of green en waste e compo mpost st or manur ure e compo mpost st (Powlson wlson et al. 2011) 1)

• Additional studies…

Using ng biosolid

• lids

s mitig igates ates climate ate chan ange ge

Preliminary findings of biosolids carbon sequestration research

1 2 3 4 5 6 7 0-10cm 10-30cm 30-50cm 50-75cm 75-100cm

control biosolids Soil Depth (cm) Soil Carbon bon (%)

• Collection

ection System em Division sion – Permits its and monitors itors discharge harges s into

• the

sewer er system tem

How do we ensure we produce high quality biosolids?

• Engin

ineeri eering ng - Provides vides long g range e planni ning ng and daily suppo port rt for biosoli solids s production duction

How do we ensure we produce high quality biosolids?

• Maintena

enance nce - Performs forms preventat entative ive and emergency rgency maintena tenance nce to ensure ure conti tinu nued ed product duction ion of high quali lity ty bioso solid ids s

How do we ensure we produce high quality biosolids?

• Operations

ations - Operates ates the Wastewa ewater ter treatment tment plant t according

• rding to

establi blished shed operation rational al proced

• cedure

ure to prod

• duce

uce high gh quality ity bioso solid ids

How do we ensure we produce high quality biosolids?

• Laboratory
• ratory – Monitors

tors key parameter meters s of biosoli solids s quality ity

How do we ensure we produce high quality biosolids?

Digester 1 Mesophilic 90° F

Class A Biosolids at Oceanside via TPAD

• TPAD - Temperature Phased Anaerobic

Digestion

• Oceanside treatment plant

transitioning to class A using TPAD

• Class A biosolids have been treated to

eliminate pathogens

• Class B biosolids are treated to greatly

reduce pathogens

Digester 2,3,4 Thermophilic > 131° F Digester 1 Mesophilic 90° F

• THP - Thermal Hydrolysis Process

(steam and high pressure)

• Increases biogas production
• Smaller footprint
• Construction began in 2018
• Anticipated operation in 2023

Class A Biosolids at Southeast via THP

Operators ensure Critical Control Points run properly

• SOPs – Operators know SOPs for their

process area

• Logsheets – logsheet for each process

area is completed as scheduled

• Monitoring and measurement – Sampling

for process control/compliance areas is conducted

• Digester temperatures are critical
• Digester detention time is critical

Dewatering

Operational Controls

Keep centrifuge (SEP SEP) or screw press (OSP) feed solids consistent Check centrate/pressate quality and flocculation performance (rough indicator of performance) Adjust polymer dosage to meet solids target range (25%TS)

New Valmet %TS meter at OSP screw press to check final TS quality

Effects

Wetter cake minimizes how much material we can store at the plant and costs more to haul Wetter cake (TS< 12%) can be dangerous to haul Cake that is too wet cannot be hauled in the end- dump trucks If final biosolids quality is compromised, we may not be able to beneficially use the biosolids

Thank you for listening! Questions?