High-severity controls
Controls
Risk Register
A technical and operating risk register for connecting sewage-to-fuel uncertainty to triggers, mitigation actions, and owner lenses.
Technical risks
Owner lenses
TechnicalHigh
Feedstock variability breaks the assumed conversion envelope.
- Trigger
- Volatile solids, ash, or moisture moves outside the modeled intake bands.
- Mitigation
- Create feedstock classes, normalize yields by dry volatile solids, and require rolling sample statistics.
- Owner lens
- Technical reviewer
OperationsHigh
Aqueous phase recycle creates unmodeled treatment burden.
- Trigger
- COD, ammonia, inhibition, or nitrification impacts exceed plant return-stream tolerance.
- Mitigation
- Run compatibility tests before pilot recycle and include pretreatment energy in every scenario.
- Owner lens
- Plant operator
SafetyHigh
Pressure and hot-water processing create unacceptable pilot safety exposure.
- Trigger
- HTL operating pressure, corrosion, or solids handling exceeds the pilot equipment safety case.
- Mitigation
- Use rated equipment, pressure relief review, corrosion coupon testing, and operator lockout procedures.
- Owner lens
- Safety lead
CommercialMedium
Hydrotreating demand erases the carbon benefit.
- Trigger
- Hydrogen intensity or catalyst replacement dominates opex and non-biogenic emissions.
- Mitigation
- Track hydrogen source, nitrogen removal, catalyst life, and product market alternatives.
- Owner lens
- Investor
RegulatoryMedium
Permit boundary is unclear for sidestreams and residuals.
- Trigger
- Return streams, residual solids, PFAS indicators, or nutrient concentrates lack an approved routing path.
- Mitigation
- Map permit boundary before field testing and keep residual handling outside fuel-value claims until approved.
- Owner lens
- Policy reviewer
CommercialWatch
Economics depend on credits that cannot be contracted.
- Trigger
- Avoided disposal, carbon credit, or renewable fuel value lacks a site-specific counterparty.
- Mitigation
- Separate contracted value from upside value and run economics with conservative credit assumptions.
- Owner lens
- Commercial lead