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

SFPUC Biosolids A resource we all help make

Agenda • 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

Wastewater Basics Inputs Fats, oils and grease Influent Contaminants of Emerging Concern Stormwater Outputs Effluent Biosolids GHG emissions

Shifting the Balance Sheet Liabiliti ties Assets ts • Effluent • Recycled water • Methane emissions • Vehicle fuel / renewable gas • Biosolids • Soil amendments / C seq. • Nitrogen/Phosphorus • Fertilizers 4

Uniquely Suited to Address Big Issues Water Energy WWRFs RFs Carbon

How Does This Impact Our Operations? • Provide a Reliable, Resilient & Flexible System that SFPUC Capital Upgrades 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 oding ing • Provide Benefi efits ts to Local Communit mmunities ies • Modify the System to Adapt t to Climate ate Change nge

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

Soil Fertility – The Reason We Ate Yesterday • Nitrogen, Phosphorus, Potassium, Sulfur, Calcium, etc. • There is a finite amount of these nutrients in the soil

We greatly reduced limits on soil fertility with synthetic fertilizers

We are utterly dependent on inorganic fertilizer

Our Digesters Capture these Nutrients • 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 organic matter

Biosolids Not Only Return Nutrients to Soils… • Inorganic fertilizers are elements • Slow release of N, P, • Increases water decoupled from carbon, leading to K, S, Ca, Mg, B, Cu, infiltration rate leaching and pollution Mn, Fe, Mo, Zn, etc. • Decreases erosion • SFPUC Biosolids are 60% carbon Increases water Increases soil • • compounds holding capacity microbial activity • Improves soil • Increases nutrient structure 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

Using ng biosolid olids s mitig igates ates climate ate chan ange ge • 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 ouse se gas offsets fsets even when n taking ng into o accou ount nt transp sportation tation and other er emissio sions ns associa ociated ted with comp mpos ost 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 0 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…

Preliminary findings of biosolids carbon sequestration research 7 6 control biosolids 5 bon (%) 4 Soil Carbon 3 2 1 0 0-10cm 10-30cm 30-50cm 50-75cm 75-100cm Soil Depth (cm)

How do we ensure we produce high quality biosolids? • Collection ection System em Division sion – Permits its and monitors itors discharge harges s into o 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 ording to establi blished shed operation rational al proced ocedure ure to prod oduce uce high gh quality ity bioso solid ids

How do we ensure we produce high quality biosolids? • Laboratory oratory – Monitors tors key parameter meters s of biosoli solids s quality ity

Class A Biosolids at Oceanside via TPAD Digester 1 Mesophilic 90° F Digester 2,3,4 Digester 1 • TPAD - Temperature Phased Anaerobic Thermophilic Mesophilic Digestion > 131° F 90° F • 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

Class A Biosolids at Southeast via THP • THP - Thermal Hydrolysis Process (steam and high pressure) • Increases biogas production • Smaller footprint • Construction began in 2018 • Anticipated operation in 2023

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?