LCFA Inhibition
Executive Summary
LCFA inhibition in anaerobic digesters is a kinetic mismatch problem, not a capacity limitation. FOG possesses 2-3x the methane potential of carbohydrate waste but remains inaccessible because lipase-mediated hydrolysis releases LCFAs in hours while syntrophic β-oxidation takes days. Multiple proven interventions exist: bentonite buffering is TRL 8 with immediate deployment; VFA-based predictive control enables closed-loop optimization; conductive biochar offers breakthrough potential by bypassing hydrogen-mediated syntrophy entirely.
Is immediate low-risk capacity increase sufficient (bentonite → 25-35% improvement), or do you need maximum capacity and are willing to invest in monitoring infrastructure? If the latter, layer VFA control on top of bentonite, then evaluate biochar for the >40% FOG loading regime.
Solvable
Bentonite buffering is well-proven chemistry with 30+ years of application in related fields. The intervention is cheap ($5-20K/year), low-risk, and can be validated in 2-3 weeks. Higher-ceiling innovations (biochar DIET) offer additional upside with moderate development risk.
Implement bentonite clay buffering (5-10 g/L) with pulse-dosing synchronized to FOG feeding schedule. Expected outcome: 25-35% increase in FOG processing capacity within 4-8 weeks. Investment: $5,000-20,000/year for materials plus $2,000-5,000 for dosing equipment. Layer on VFA-based predictive control ($20,000-50,000) to potentially reach 40-50% FOG loading.
The Brief
Our anaerobic digester handles food waste but biogas yield crashes when we add more than 15% fats/oils/grease due to LCFA inhibition. We want to process higher-calorie waste streams without digester upset.
Problem Analysis
When FOG exceeds approximately 15% of feed, a cascade failure occurs: long-chain fatty acids (LCFAs) released from lipid hydrolysis adsorb onto methanogen cell membranes faster than syntrophic bacteria can degrade them. Propionate accumulates, pH drops, biogas production crashes over 5-14 days. The underlying issue is that FOG possesses 2-3x the methane potential of carbohydrate waste but remains inaccessible due to inhibition dynamics. This is a kinetic mismatch, not a capacity limitation.
The fundamental challenge is kinetic mismatch rather than capacity limitation. Lipase-mediated hydrolysis releases LCFAs in hours, but syntrophic β-oxidation takes days because it's thermodynamically unfavorable without tight hydrogen coupling. This creates a self-reinforcing failure loop: when methanogens are inhibited by LCFA membrane adsorption, hydrogen accumulates, β-oxidation stalls, more LCFA accumulates, and the system crashes.
ΔG°' = +345 kJ/mol for palmitate β-oxidation to acetate + H₂; only favorable when H₂ partial pressure < 10⁻⁴ atm
Syntrophic β-oxidation is thermodynamically uphill under standard conditions. It only proceeds when hydrogenotrophic methanogens maintain hydrogen partial pressure below 10⁻⁴ atm. When methanogens are inhibited by LCFA, hydrogen accumulates, β-oxidation stalls, and the cascade failure begins.
The bottleneck is spatial organization, not microbial capability
Your digester contains organisms capable of degrading LCFAs—they're just dispersed and wash out before establishing syntrophic partnerships. UASB granules achieve 5-10x higher LCFA degradation rates not because they have different organisms, but because the <100 μm diffusion distances within granules enable the tight hydrogen coupling that makes β-oxidation thermodynamically favorable. The intervention leverage point is creating microenvironments that mimic granule architecture.
Dilution—limit FOG to 10-20%, blend with low-lipid substrates
Caps revenue potential; doesn't address underlying kinetic mismatch
Pulse feeding—intermittent FOG addition with recovery periods
Requires precise monitoring; many operators use suboptimal fixed schedules
Calcium/magnesium addition—precipitate LCFA as insoluble salts
Reduces methane yield by 15-25% by permanently sequestering substrate
Two-phase digestion—separate acidogenic and methanogenic stages
Capital-intensive ($500K+); significant operational complexity
Commercial UASB reactors (Malaysia, Indonesia)[1]
Granular sludge with high syntrophic density
4-6 g/L lipids, >80% COD removal
Efficiency optimization
European food waste digesters[2]
Pulse feeding with VFA monitoring
15-25% FOG loading with adapted biomass
Push toward 30%
Slaughterhouse waste digesters (Denmark, Germany)[3]
Two-phase systems with thermal pretreatment
>40% fat substrates
Cost reduction
[1] Palm oil mill effluent treatment
[2] Industry practice
[3] Commercial operation
[1] Palm oil mill effluent treatment
[2] Industry practice
[3] Commercial operation
Kinetic mismatch between hydrolysis and β-oxidation
90% confidenceVFA profiles consistently show LCFA spike followed by propionate accumulation before crash; timing matches kinetic models
Dispersed sludge lacks spatial organization for syntrophy
85% confidenceUASB granular systems achieve 5-10x higher LCFA degradation rates with same organisms; difference is architecture not biology
Methanogen membrane toxicity creates self-reinforcing crash
80% confidenceMembrane-associated LCFA correlates with toxicity better than bulk concentration; washing restores activity
FOG loading capacity
Unit: % of total VS
Specific methane yield
Unit: m³ CH₄/kg VS added
Recovery time from upset
Unit: days to 90% baseline
ROI on intervention
Unit: months
Constraints
- Existing CSTR digester infrastructure (mesophilic, 20-30 day HRT)
- Continuous or semi-continuous feeding requirement
- Regulatory compliance for digestate disposal
- Cannot accept extended (>2 week) digester downtime
- Operational simplicity preferred
- CAPEX preference <$100,000 for initial interventions
- Payback period <18 months preferred
- Minimal operator retraining required
- 15% FOG threshold is accurately measured (VS basis, not wet weight)
- FOG is predominantly triglycerides with PU adhesive (not free fatty acids)
- Digestate end-use permits clay/biochar additives
- Current biogas offtake can absorb increased production
FOG loading capacity
Unit: % of VS feed
Methane yield
Unit: % of theoretical
Payback period
Unit: months
First Principles Innovation
Instead of 'how do we accelerate LCFA degradation?' ask 'how do we prevent LCFA accumulation above toxicity threshold while maintaining bioavailability?'
Solutions
We identified 6 solutions across three readiness levels.
Start with the Engineering Path. Run R&D in parallel if you need breakthrough potential or competitive differentiation.
Engineering Path
Proven technologies, often borrowed from other industries. The work is adaptation, integration, and validation, not discovery.
Bentonite Clay Buffering with Synchronized Dosing
Choose this path if You want low-risk, low-cost immediate improvement without major infrastructure changes. Best when digestate regulations permit clay additives and you can implement pulse-dosing synchronized to FOG feeding. Ideal starting point for any high-FOG operation.
Add bentonite clay (5-10 g/L) as LCFA adsorption buffer. Bentonite's layered aluminosilicate structure provides 400-800 m²/g surface area with hydrophobic interlayer spaces that reversibly adsorb LCFAs. Pulse-dose 30-60 minutes before FOG feeding to maximize buffering during peak loading.
**Mechanism:** During FOG feeding, LCFAs partition onto clay surfaces rather than methanogen membranes. As bulk LCFA is consumed by β-oxidation, equilibrium drives desorption, maintaining steady-state concentration below the ~1 g/L toxicity threshold. **Adsorption chemistry:** LCFA adsorption onto bentonite occurs through three mechanisms: (1) hydrophobic interactions between fatty acid chains and siloxane surfaces, (2) hydrogen bonding between carboxyl groups and edge hydroxyl groups, (3) intercalation into interlayer spaces for shorter-chain acids. **Dosing protocol:** Rather than continuous addition, pulse-dose bentonite 30-60 minutes before FOG addition to maximize buffering capacity during peak loading. At 10 g/L bentonite, you can buffer approximately 1-3 g/L LCFA spikes. **Secondary benefit:** Clay particles provide attachment surfaces for syntrophic biofilms, potentially improving LCFA-oxidizer retention over time.
The adsorption isotherm follows Langmuir behavior with Ka ~10⁻⁴ to 10⁻³ L/mg depending on LCFA chain length. Critically, this is reversible—as bulk LCFA concentration drops through β-oxidation, equilibrium drives desorption with 4-12 hour half-time that matches degradation timescale. The clay acts as a buffer, not a sink.
Reversible adsorption-desorption equilibrium can buffer concentration spikes without removing substrate from bioavailability
Oil well drilling. Bentonite controls fluid rheology and adsorbs hydrocarbons in drilling mud operations
Same hydrophobic adsorption chemistry applies to LCFA; reversible binding maintains bioavailability for degradation
Not missed—bentonite addition is known. What's underutilized is synchronized pulse-dosing optimized for FOG feeding schedule. Most operators either don't use it or use suboptimal continuous dosing.
Solution Viability
Bentonite-LCFA adsorption is well-characterized chemistry with 30+ years of application in drilling muds and environmental remediation. This is protocol optimization, not technology development. TRL 8.
What Needs to Be Solved
Site-specific adsorption capacity validation
Bentonite adsorption capacity varies with LCFA chain length and saturation. Site-specific FOG composition determines whether standard dosing is sufficient or optimization is needed.
Literature values (0.1-0.3 g LCFA/g bentonite) span 3x range. Site-specific validation eliminates this uncertainty cheaply.
Path Forward
Bench-scale adsorption isotherm test with site-specific FOG and bentonite. Measure capacity and desorption kinetics.
Bentonite adsorbs all LCFAs; the question is capacity optimization, not fundamental chemistry. Even suboptimal dosing provides benefit.
You (internal team)
Days
$2,000-5,000
If You Pursue This Route
Order sodium bentonite (drilling grade, ~$500/tonne). Run jar test at 5 g/L and 10 g/L with representative FOG sample. Measure residual LCFA at 1, 4, 12, 24 hours.
Adsorption capacity >0.1 g LCFA/g bentonite and desorption half-time <24 hours → proceed to full-scale. Capacity <0.05 g/g → evaluate alternative clays or biochar.
Run a New Analysis with this prompt:
“Optimize bentonite dosing protocol for specific FOG composition and feeding schedule”
If This Doesn't Work
VFA-Based Predictive Pulse-Feeding Control
If bentonite alone provides <15% capacity improvement, or if digestate regulations prohibit clay addition.
25-35% increase in FOG loading capacity
2-4 weeks to optimize dosing protocol
$5,000-20,000/year for materials; $2,000-5,000 for dosing equipment
- Adsorption capacity may be insufficient for very high FOG spikes or specific LCFA compositions (short-chain, highly unsaturated)
- Digestate disposal regulations may restrict clay additives in some jurisdictions
- Long-term clay accumulation may require periodic desludging
- Operator adoption of pulse-dosing protocol may be inconsistent
Bench-scale adsorption isotherm with site-specific FOG
Method: Jar test at 5 g/L and 10 g/L bentonite with representative FOG; measure LCFA at 1, 4, 12, 24 hours by GC-FID
Success: Adsorption capacity >0.1 g LCFA/g bentonite; desorption half-time <24 hours
If capacity <0.05 g/g → evaluate organoclay or biochar alternatives
VFA-Based Predictive Pulse-Feeding Control
Propionate:acetate ratio provides 24-48 hour leading indicator for safe feeding windows
Choose this path if You want to maximize capacity beyond what bentonite alone provides, or need objective data to push loading aggressively. Best when you can invest $20-50K in monitoring infrastructure and have SCADA capability for closed-loop control.
Automated pulse-feeding for FOG based on real-time VFA monitoring. Propionate accumulation precedes methanogenesis failure by 24-48 hours, providing leading indicator. **Operating logic:** When propionate:acetate ratio is <0.5 and biogas production is stable, system can accept FOG pulse. When ratio approaches 1.0, feeding pauses until recovery. **Algorithm development:** The algorithm learns your system's specific recovery kinetics over 3-4 weeks, then optimizes pulse size and frequency.
Propionate accumulation signals syntrophic bottleneck—when propionate-oxidizing syntrophs are inhibited by high H₂ partial pressure or direct LCFA toxicity, propionate accumulates before acetate and before biogas production drops. This 24-48 hour warning window enables proactive intervention.
Solution Viability
Commercial VFA analyzers (Hach, AppliTek, s::can) are proven technology. The innovation is integration with feeding control, not the sensing itself.
What Needs to Be Solved
Sensor fouling and calibration drift in digester environment
Digester conditions (high solids, biofilm formation) can foul sensors. False readings lead to either over-conservative feeding or missed warning signs.
Sensor maintenance is a known challenge but manageable with proper protocols. Most failures are operational, not fundamental.
Path Forward
Install VFA analyzer with automated cleaning system. Establish weekly calibration protocol. Build 3-4 weeks of baseline data before enabling closed-loop control.
Multiple commercial installations demonstrate feasibility. Key is maintenance protocol commitment.
Supplier / Vendor
Weeks
$20,000-50,000
As complement to bentonite for maximum capacity. Can also be used alone if digestate regulations prohibit clay addition.
Granular Sludge Seeding from Lipid-Treating UASB
Import immediate LCFA processing capacity from established syntrophic communities
Choose this path if You need >50% capacity increase and are willing to invest in retention infrastructure. Best when you have access to granular sludge source (nearby palm oil mill, dairy processor, slaughterhouse) and can modify CSTR with settling zone or baffles.
Source granular sludge from established UASB reactors treating lipid-rich wastewater and add as 'starter culture' to CSTR. Granules are dense (1.0-1.05 g/cm³), self-immobilized microbial aggregates with layered structure optimized for LCFA degradation. **Capacity addition:** Adding 5-10% granular sludge by volume provides immediate LCFA processing capacity without 3-6 month acclimation period.
Within granules, Syntrophomonas species perform β-oxidation via sequential C2 cleavage, generating acetyl-CoA and releasing 2H per cycle. The <100 μm diffusion distance to adjacent hydrogenotrophic methanogens maintains H₂ partial pressure <10⁻⁴ atm, making the otherwise unfavorable reaction thermodynamically favorable.
Solution Viability
Granular sludge provides immediate capacity, but CSTR mixing and HRT will wash out granules without retention strategy. Success depends on retention infrastructure.
What Needs to Be Solved
Granule disintegration and washout under CSTR mixing
Granules are self-immobilized aggregates optimized for quiescent UASB conditions. CSTR mixing shear may break granules; HRT will wash fragments out without retention.
Multiple CSTR bioaugmentation attempts have failed due to washout. Success requires retention infrastructure modification.
Path Forward
Install internal settling zone, baffles, or biofilm carriers to retain granules and fragments. Source granules from established lipid-treating UASB.
Retention infrastructure can be engineered, but adds complexity and cost. May be justified only for very high FOG targets.
Industry Partner
Months
$50,000-150,000 for retention infrastructure
When bentonite + pulse feeding hits ceiling and >50% capacity increase needed. Requires commitment to retention infrastructure.
R&D Path
Fundamentally different approaches that could provide competitive advantage if successful. Pursue as parallel bets alongside solution concepts.
Conductive Biochar Addition for DIET Enhancement
Choose this path if You want to address the fundamental thermodynamic bottleneck and are willing to accept development risk. Best when you can run parallel bench-scale validation while implementing bentonite as primary approach. Ideal for organizations targeting >40% FOG loading.
**Mechanism:** In conventional syntrophy, LCFA-oxidizers transfer electrons to hydrogen, which diffuses to methanogens. This requires maintaining H₂ partial pressure <10⁻⁴ atm—the thermodynamic constraint causing crashes. With DIET, electrons flow directly from LCFA-oxidizer outer membrane cytochromes through conductive biochar to methanogen surface proteins, enabling CO₂ reduction to methane without hydrogen intermediate. **Material properties:** Biochar pyrolyzed at 500-700°C has electrical conductivity of 0.1-10 S/m due to graphitic carbon domains. LCFA-oxidizing bacteria (Geobacter, some Syntrophomonas) can use biochar as electron acceptor; methanogens (Methanosarcina, Methanothrix) can accept electrons from biochar. **Benefit cascade:** Eliminates hydrogen partial pressure constraint, removes thermodynamic bottleneck on β-oxidation rate. Biochar also provides adsorption buffering (similar to bentonite) and biofilm attachment surfaces—multiple mechanisms of benefit.
The thermodynamic constraint on syntrophic β-oxidation is the requirement for extremely low H₂ partial pressure. DIET eliminates this constraint by providing an alternative electron pathway. Even if DIET is less efficient than optimal hydrogen-mediated syntrophy, it provides a robust backup pathway that prevents complete system failure.
Conductive materials can bypass hydrogen-mediated syntrophy via direct interspecies electron transfer (DIET)
If it works: Removes the fundamental thermodynamic constraint on LCFA degradation rate
Improvement: 30-50% improvement in LCFA degradation rate based on propionate/butyrate results
Solution Viability
DIET mechanism is proven for VFA oxidation (propionate, butyrate). The question is whether LCFA-oxidizing bacteria couple as effectively via direct electron transfer as VFA-oxidizers do.
What Needs to Be Solved
LCFA-specific DIET coupling efficiency unknown
Most DIET literature focuses on propionate and butyrate oxidation. LCFA-oxidizers (Syntrophomonas) may or may not express the outer membrane cytochromes needed for effective electron transfer to biochar.
Limited direct evidence for LCFA-specific DIET. Zhao et al. (2017) showed enhancement for LCFA precursors but not pure LCFA substrates.
Path Forward
Run BMP test with and without biochar using oleate or palmitate as sole carbon source. Measure methane production rate improvement.
Even if DIET coupling is weaker for LCFA than VFA, biochar provides adsorption buffering and biofilm attachment—multiple benefit mechanisms.
You (internal team)
Weeks
$5,000-10,000
If You Pursue This Route
Source high-conductivity biochar (pyrolyzed at 600-700°C). Run parallel BMP tests with oleate substrate: control vs. 10 g/L biochar vs. 10 g/L bentonite.
Biochar shows >20% improvement over control → proceed to pilot addition. If <10% improvement → continue with bentonite as primary.
Run a New Analysis with this prompt:
“Review DIET literature for LCFA-specific evidence and identify optimal biochar specifications”
If This Doesn't Work
Lipase Inhibition for Hydrolysis Rate-Matching
If LCFA-specific BMP shows minimal DIET benefit, pivot to controlling the fast step (hydrolysis) rather than accelerating the slow step.
Lipase Inhibition for Hydrolysis Rate-Matching
Slow the fast step (hydrolysis) to match β-oxidation capacity—counterintuitive but thermodynamically sound
Choose this path if You have access to cheap tannin waste streams (tea/coffee grounds, grape pomace) and want to avoid additives that accumulate in digestate. Best when LCFA spikes are the primary problem and you want to smooth loading rather than increase capacity.
Ceiling: Complete elimination of LCFA spikes by matching hydrolysis to degradation capacity; potential for very high FOG loading if rate-matched
Key uncertainty: Finding optimal inhibition level that smooths LCFA release without blocking hydrolysis entirely
Elevate when: If bentonite buffering is insufficient and you have access to cheap tannin waste streams. Particularly attractive when LCFA spikes are the primary failure mode.
Rumen-Derived Syntrophic Consortium with Oleophilic Carriers
Import 5-10x faster LCFA degraders from rumen environment, retained on oleophilic carriers
Choose this path if You have access to rumen fluid source (nearby slaughterhouse, dairy with cannulated cattle) and are willing to invest in carrier infrastructure. Best for unsaturated-rich FOG where biohydrogenation provides additional benefit.
Ceiling: 5-10x LCFA degradation rate improvement; potential for >50% FOG loading with proper retention
Key uncertainty: Consortium sourcing, carrier colonization, and temperature compatibility
Elevate when: If simpler approaches (bentonite, biochar) hit ceiling at <40% FOG and access to rumen source exists.
Frontier Watch
Technologies worth monitoring.
Electrochemical LCFA Oxidation via Bioelectrochemical Systems
EMERGING_SCIENCE4
Electrodes provide unlimited electron sink independent of hydrogen partial pressure
Electrodes provide unlimited, tunable electron sink not dependent on hydrogen partial pressure. Could fundamentally eliminate the thermodynamic constraint on LCFA degradation. Electromethanogenesis at cathode provides redundant methanogenesis pathway.
Capital cost ($500K-2M for full-scale electrode installation), electrode fouling and maintenance in digester environment, scaling from lab to full-scale is major uncertainty. This is a 2-5 year R&D project, not near-term implementation.
Trigger: Electrode cost drops below $100/m²; pilot-scale demonstration shows >50% LCFA degradation improvement with <2 year electrode lifetime
Earliest viability: 3-5 years
Monitor: Dr. Derek Lovley (UMass Amherst)—pioneer of electromicrobiology; Dr. Korneel Rabaey (Ghent)—leading bioelectrochemical systems lab; ISMET conference proceedings
Stratified Reactor with Floating Layer Management
PARADIGM3
Convert floating FOG layer from problem to feature via micro-aerobic surface treatment
Converts a 'problem' (floating FOG layer) into a process feature. Aerobic β-oxidation is thermodynamically favorable (ΔG°' = -129 kJ/mol per cycle) and doesn't require syntrophic hydrogen transfer. Could enable 100-300% FOG loading increase.
Significant retrofit complexity ($100K-500K); oxygen carryover to main reactor is real risk requiring careful engineering; challenges fundamental CSTR design philosophy.
Trigger: Pilot demonstration showing >100% FOG loading increase with <5% oxygen carryover; or modular retrofit kit at <$50K
Earliest viability: 2-3 years
Monitor: Dr. Irini Angelidaki (DTU)—leading AD research; Cambi and Veolia THP divisions; European Biogas Association technical groups
Risks & Watchouts
What could go wrong.
Digestate disposal regulations may restrict clay/biochar additives
Check local regulations before implementation; bentonite and biochar are generally accepted as soil amendments but verify specific requirements
Feedstock variability—interventions optimized for one FOG source may fail with another
Characterize FOG sources; maintain VFA monitoring as safety net; build operational flexibility into protocols
Operator skill and engagement significantly affects real-world performance
Choose simpler interventions (bentonite) before complex ones (bioaugmentation); invest in operator training; provide objective feedback via monitoring
Long-term intervention stability less certain than short-term performance
Plan for monitoring and adjustment over time; have fallback options ready; avoid over-committing based on initial results
Self-Critique
Where we might be wrong.
Medium
High confidence in primary recommendation (bentonite buffering is well-proven chemistry). Medium confidence in capacity improvement estimates (site-specific factors dominate). Lower confidence in innovation concepts (DIET for LCFA specifically is less directly validated than for VFA).
Bentonite adsorption capacity may be insufficient for very high FOG spikes or specific LCFA compositions
DIET enhancement for LCFA specifically may be weaker than propionate/butyrate results suggest
Operator adoption of new protocols may be slower or more challenging than assumed
Long-term clay/biochar accumulation effects may require more frequent desludging than anticipated
Thermal pretreatment (THP) for LCFA chain-cracking—existing infrastructure at some sites could be leveraged
Partial saponification with potassium hydroxide—may provide toxicity reduction while maintaining bioavailability
FOG diversion to biodiesel production—economic alternative to digester capacity expansion
Membrane-based LCFA extraction—remove problem fraction for separate processing
Bentonite capacity sufficiency for specific FOG
First validation includes adsorption isotherm test with site-specific FOG; no-go criteria defined
DIET enhancement for LCFA specifically
Biochar validation includes LCFA-specific BMP test; fallback to bentonite if minimal improvement
Long-term additive accumulation
Monitor digestate solids; periodic desludging if needed; materials are non-toxic and accepted for land application
Operator adoption challenges
Recommend simplest interventions first; VFA monitoring provides objective feedback loop
Assumption Check
We assumed your constraints are fixed. If any can flex, here's what changes—and what to reconsider.
Characterize FOG composition and loading methodology precisely before investing; problem severity may differ from assumptions.
For >50% FOG loading long-term, evaluate whether CSTR retrofit vs. new reactor investment makes economic sense.
Evaluate FOG diversion to biodiesel production as economic alternative before investing in digester modifications.
Final Recommendation
Personal recommendation from the analysis.
**Start with bentonite tomorrow.** It's cheap ($5-20K/year), low-risk, and you can validate it in 2-3 weeks with a simple jar test. Don't overthink the dosing—start at 5 g/L, pulse it 30-60 minutes before FOG feeding, and watch your VFA profiles. You'll know within a month if it's working.
**While bentonite is running, install VFA monitoring.** Not because you need it immediately, but because it gives you the data to push harder. Once you can see propionate:acetate ratios in real-time, you can optimize pulse feeding and potentially reach 30-40% FOG loading.
**Run a biochar BMP test in parallel**—$5-10K and 6-8 weeks to know if DIET is worth pursuing. If it shows >20% improvement over bentonite, consider transitioning as the DIET-capable community develops over 6 months.
**Don't touch the complex innovations yet.** Rumen consortium, stratified reactor, electrochemical systems—they're intellectually interesting but the operational complexity is real. If you're still hitting a ceiling at 40% FOG after bentonite + VFA control + biochar, then we can talk about bioaugmentation or reactor modifications.
**One thing I'd definitely do: characterize your FOG better.** Know whether it's saturated or unsaturated-dominant, what the actual lipid content is, and how variable it is batch-to-batch. This affects which interventions matter most.