residual markers tracked
Docker-Generated Residuals Screen
Residuals Fate Lab
A 3D routing lab for hydrochar, ash, phosphorus, regulated metals, PFAS-sensitive reuse, catalyst protection, and final disposal decisions.
critical metal/metalloid gates
kg P estimated in hydrochar per tonne dry sludge
kg hydrochar modeled per tonne dry sludge
Value branch. Use hydrochar as a phosphorus resource only if metal co-leaching and PFAS routing are closed.
Acid leach plus P recovery
Wet-chemical hydrochar treatment can recover phosphorus but can also leach heavy metals into a liquid stream that must be managed.
P yield, acid demand, metal co-leaching, spent acid treatment, residual hydrochar use, and PFAS partitioning.MgCl2-assisted apatite shift
MgCl2 can push phosphorus into apatite-like hydrochar phases and improve biocrude quality, but may move metals to aqueous products.
Mg dose, chloride corrosion, apatite stability, aqueous metals, biocrude nitrogen/oxygen, and residual classification.The Docker selection model pairs Acid leach plus P recovery + Mineral lockup / vitrification + MgCl2-assisted apatite shift as the current residual portfolio under phosphorus, metals, PFAS, and cost gates.
Current residuals decision
Recover phosphorus only with a closed metals and PFAS ledger
The generated screen ranks acid leaching plus phosphorus recovery first, but it also makes the hard caveat visible: wet-chemical recovery can move metals into liquid streams. Land application remains a hold gate until PFAS, metals, leachability, crop/soil exposure, and liability checks pass.
Struvite
MgNH4PO4A familiar fertilizer product lens for ammonium and phosphorus recovery.
7.92 kg product/kg PHydroxyapatite / apatite phosphate
Ca5HO13P3Mg/Ca-assisted HTL can shift phosphorus into stable apatite-like mineral phases.
5.41 kg product/kg PVivianite
Fe3O8P2pH-controlled release and iron chemistry can make vivianite a phosphorus recovery target.
8.1 kg product/kg PPhosphorus recovery
59.4Acid leach plus P recovery
Wet-chemical hydrochar treatment can recover phosphorus but can also leach heavy metals into a liquid stream that must be managed.
- P recovery
- 82
- Metal isolation
- 58
- PFAS fit
- 46
- Must prove
- P yield, acid demand, metal co-leaching, spent acid treatment, residual hydrochar use, and PFAS partitioning.
Disposal isolation
59.2Mineral lockup / vitrification
High-temperature or mineral lockup routes can prioritize isolation where reuse is blocked by metals or PFAS.
- P recovery
- 18
- Metal isolation
- 86
- PFAS fit
- 68
- Must prove
- Leachability, thermal emissions, ash acceptance, PFAS destruction/retention, cost, and whether phosphorus value is lost.
Fuel-upgrading protection
55.3Demetallization plus guard bed
Protects hydrotreating catalyst from ash and metals even if it does not create a fertilizer product.
- P recovery
- 28
- Metal isolation
- 74
- PFAS fit
- 38
- Must prove
- Organic loss, metals removal, wastewater burden, spent sorbent fate, and catalyst-life improvement.
In-reactor P steering
55.1MgCl2-assisted apatite shift
MgCl2 can push phosphorus into apatite-like hydrochar phases and improve biocrude quality, but may move metals to aqueous products.
- P recovery
- 76
- Metal isolation
- 42
- PFAS fit
- 40
- Must prove
- Mg dose, chloride corrosion, apatite stability, aqueous metals, biocrude nitrogen/oxygen, and residual classification.
Iron phosphate recovery
51pH-controlled vivianite recovery
2026 pH-controlled microwave work suggests a route to solubilize sludge phosphorus and recover vivianite.
- P recovery
- 72
- Metal isolation
- 54
- PFAS fit
- 34
- Must prove
- Microwave energy, pH control, iron speciation, product purity, metals carryover, and compatibility with HTL flows.
Circular material watch
45.9Hydrochar adsorbent or catalyst support
Biosolids hydrochar may become an adsorbent or catalyst support, but heavy metals and PFAS can block open-loop reuse.
- P recovery
- 36
- Metal isolation
- 50
- PFAS fit
- 30
- Must prove
- Surface area, leaching, PFAS, metals, regeneration, product safety, and end-of-life disposal.
Regulatory gate
33.4Land application hold gate
Nutrient value is real, but PFAS and metals make land application a hold gate rather than a default outlet.
- P recovery
- 54
- Metal isolation
- 20
- PFAS fit
- 8
- Must prove
- EPA/state limits, PFAS panel, cumulative metals, crop/soil exposure, public acceptance, and liability.
Generated residual portfolio
Three-route branch under phosphorus, metals, PFAS, and cost gates
Acid leach plus P recovery
P yield, acid demand, metal co-leaching, spent acid treatment, residual hydrochar use, and PFAS partitioning.
Mineral lockup / vitrification
Leachability, thermal emissions, ash acceptance, PFAS destruction/retention, cost, and whether phosphorus value is lost.
MgCl2-assisted apatite shift
Mg dose, chloride corrosion, apatite stability, aqueous metals, biocrude nitrogen/oxygen, and residual classification.
Residual markers
Resource value and high-consequence metals in the same ledger
Phosphorus P
Phosphorus is the main residual value target and often concentrates in sludge hydrochar or ash.
96000 mg/kg hydrocharIron Fe
Iron drives phosphate binding, vivianite potential, ash load, and downstream solids behavior.
127555.6 mg/kg hydrocharAluminum Al
Alum-derived solids can bind phosphorus and alter hydrochar quality.
79333.3 mg/kg hydrocharCalcium Ca
Calcium additions can change PFAS, metal, and phosphate fate during hydrothermal treatment.
99666.7 mg/kg hydrocharZinc Zn
Zinc can concentrate in hydrochar and become a land-application or leaching gate.
8311.1 mg/kg hydrocharCopper Cu
Copper is a regulated biosolids metal and can influence catalyst/residual reuse decisions.
4300 mg/kg hydrocharNickel Ni
Nickel matters for both toxicity screening and any circular catalyst-support concept.
520 mg/kg hydrocharChromium Cr
Chromium speciation and leaching must be checked before residual reuse.
657.8 mg/kg hydrocharLead Pb
Lead is a high-consequence residual gate even at low mass.
425 mg/kg hydrocharCadmium Cd
Cadmium is a small-mass but high-risk land and product acceptance gate.
18.2 mg/kg hydrocharMercury Hg
Mercury needs air, aqueous, and solid residual tracking because volatility and speciation matter.
6.7 mg/kg hydrocharArsenic As
Arsenic is a high-risk residual acceptance and leachability marker.
46.7 mg/kg hydrocharresidual-p-recovery-hydrochar-2025
Phosphorus recovery from sewage sludge-derived hydrochar
Wet-chemical hydrochar work balancing phosphorus recovery, heavy-metal leaching, and residual hydrochar use.
Open sourceresidual-water-soluble-components-2025
Catalysts, feedstock properties, and water-soluble components during sewage sludge HTL
2025 catalyst/feedstock study supporting water-side chemistry checks alongside fuel yield.
Open sourceresidual-HT-additives-2025
Catalytic and co-hydrothermal treatment of sewage sludge: hydrochar, metals, and PFAS fate
Shows hydrothermal additives can change hydrochar properties, heavy-metal concentration, and PFAS fate.
Open sourceresidual-p-ml-2025
Machine-learning prediction of phosphorus fate in hydrothermal biowaste treatment
2025 work supports treating phosphorus partitioning as a modelable hydrothermal variable.
Open sourceresidual-mgcl2-p-recovery-2024
MgCl2-assisted HTL for low-N/O biocrude and phosphorus recovery
MgCl2 increased apatite-like phosphorus in hydrochar while changing heavy-metal fate.
Open sourceresidual-vivianite-2026
pH-controlled microwave treatment for vivianite recovery from sewage sludge
2026 phosphorus solubilization and vivianite recovery branch.
Open sourceresidual-p-tech-2026
Technologies and current applications of phosphorus recovery from surplus sludge
2026 review of sludge phosphorus recovery pathways.
Open sourceresidual-hydrochar-jclepro-2023
HTL hydrochar characterization, impacts, and applications
Hydrochar can concentrate phosphorus and metals, creating both recovery potential and reuse limits.
Open sourceresidual-waste-streams-energy-2023
HTL sludge-to-energy and waste-stream management
Frames hydrochar as phosphorus-rich while warning metals vary by sludge, condition, and species.
Open sourceresidual-EPA-biosolids-PFAS-2025
EPA draft sewage sludge risk assessment for PFOA and PFOS
Regulatory frame for PFAS in sewage sludge and biosolids.
Open sourceresidual-ITRC-PFAS-2026
ITRC PFAS technical and regulatory guidance update
2026 PFAS guidance relevant to biosolids, developing treatment, and residual routing.
Open sourceresidual-transforming-biosolids-2026
Future directions of biosolids thermal and hydrothermal products
2026 industry report on biosolids biochar/hydrochar uses and heavy-metal limits.
Open source