epa-treatability

EPA Drinking Water Treatability Database Skill

Accesses the EPA Treatability Database (TDB) for referenced treatment technology effectiveness data. Covers 30+ treatment processes and 120+ contaminants with removal efficiency data from peer-reviewed sources.

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Credential

None required. The EPA TDB is publicly accessible.

# No API key needed -- EPA TDB is open access

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Data Source

Field	Value
Database	EPA Drinking Water Treatability Database (TDB)
URL	https://tdb.epa.gov/
Coverage	30+ treatment processes, 120+ contaminants (including 26 PFAS)
Data sources	Peer-reviewed journals, conferences, research reports, dissertations
Target audience	Water utilities, treatment designers, researchers
API	No REST API -- web interface only
Update frequency	Periodic (not real-time)

Important: The EPA TDB does not have a public REST API. Data access is through the web interface at https://tdb.epa.gov/. This skill documents the manual access workflow and provides reference data for common treatment processes relevant to produced water and brine treatment.

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Access Workflow (Web Interface)

Search by Contaminant

1. Navigate to https://tdb.epa.gov/
2. Click "Find a Contaminant" or use the search bar
3. Select the contaminant of interest (e.g., "Total Dissolved Solids", "Barium", "Strontium")
4. View applicable treatment processes with removal efficiency data
5. Each entry includes: reference citation, percent removal or log removal, water quality conditions, operational parameters

Search by Treatment Process

1. Navigate to https://tdb.epa.gov/
2. Click "Find Treatment Process"
3. Select the process (e.g., "Reverse Osmosis", "Ion Exchange", "Electrodialysis")
4. View all contaminants treated by that process with effectiveness data

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Key Treatment Processes for Produced Water / Brine

The following treatment processes are most relevant to produced water treatment and lithium/magnesium recovery:

Membrane Processes

Process	Mechanism	TDS Range	Key Application
Reverse Osmosis (RO)	Pressure-driven membrane rejection	Feed up to ~70,000 mg/L TDS	Desalination, TDS reduction, pre-concentration
Nanofiltration (NF)	Selective membrane rejection	Feed up to ~40,000 mg/L TDS	Divalent ion removal (Mg, Ca, Ba, Sr)
Electrodialysis (ED)	Electrically driven ion transport	Feed up to ~100,000+ mg/L TDS	Selective ion removal, brine concentration
Electrodialysis Reversal (EDR)	ED with polarity reversal	Feed up to ~15,000 mg/L TDS	Scale-resistant ED variant
Membrane Distillation (MD)	Thermally driven vapor transport	Any TDS (vapor phase)	Zero-liquid discharge, high-TDS brines

Sorption / Ion Exchange

Process	Mechanism	Key Application
Ion Exchange (IX)	Selective ion exchange resin	Targeted ion removal (Li, Ba, Ra)
Activated Alumina	Adsorption on alumina surface	Fluoride, arsenic removal
Granular Activated Carbon (GAC)	Adsorption on carbon	Organics, BTEX, some metals

Chemical / Physical

Process	Mechanism	Key Application
Chemical Precipitation	Insoluble salt formation	Ba, Sr, Ra removal; lime softening for Ca, Mg
Coagulation/Flocculation	Charge neutralization + aggregation	Suspended solids, oil and grease
Electrocoagulation	Electrically generated coagulant	Oil removal from produced water
Oxidation (chemical)	Redox reactions	Iron, manganese, H2S removal
Air Stripping	Mass transfer to gas phase	VOCs, BTEX, dissolved gases

Thermal

Process	Mechanism	Key Application
Evaporation / Crystallization	Thermal concentration to solid	ZLD, very high TDS brines
Multi-Effect Distillation (MED)	Multi-stage thermal distillation	Desalination of high-TDS streams
Mechanical Vapor Recompression (MVR)	Energy-efficient evaporation	Mid-to-high TDS concentration

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Reference Removal Efficiency Data

These values are representative ranges compiled from EPA TDB, peer-reviewed literature, and produced water treatment references. Actual performance depends on feed water chemistry, temperature, and operating conditions.

Removal Efficiency by Process (Produced Water Context)

Contaminant	RO	NF	ED/EDR	IX	Chem. Precip.	GAC
TDS	95-99%	50-90%	50-95%	Variable	20-60%	Minimal
Chloride	95-99%	20-50%	50-95%	Variable	Minimal	Minimal
Calcium	95-99%	80-95%	50-90%	90-99%	80-95%	Minimal
Magnesium	95-99%	85-97%	50-90%	90-99%	80-95%	Minimal
Barium	95-99%	85-97%	50-90%	90-99%	95-99%	Minimal
Strontium	95-99%	80-95%	50-90%	90-99%	80-95%	Minimal
Iron	95-99%	80-95%	40-80%	80-99%	95-99%	30-70%
Lithium (as Li+)	90-95%	10-30%	30-70%	50-99%*	Minimal	Minimal
Oil and Grease	95-99%**	90-99%**	Low	Minimal	60-90%	80-95%
BTEX	95-99%	50-80%	Low	Minimal	Minimal	90-99%

*Li removal by IX depends entirely on sorbent selectivity. Li-selective sorbents (LMO, LTO) achieve 90-99% Li extraction from brine; conventional cation exchange is less selective.

**Membranes require pre-treatment to remove oil/grease to prevent fouling.

Selective Lithium Recovery Technologies

These are not in the EPA TDB but are the primary DLE treatment approaches:

Technology	Selectivity	Li Recovery	Feed TDS	Status
LMO sorbent (H2MnO3)	Li vs. Na, Ca, Mg	85-95%	Up to 200,000+ mg/L	Pilot/commercial
LTO sorbent (H2TiO3)	Li vs. Na, Ca, Mg	80-90%	Up to 200,000+ mg/L	Pilot
Solvent extraction (TBP/DEHPA)	Li vs. other cations	80-95%	Up to 300,000+ mg/L	Commercial (Salar)
Electrochemical (LiFePO4)	Li vs. Na	70-90%	Up to 100,000 mg/L	Lab/pilot
Alumina-based sorbent	Li vs. Mg	70-85%	Up to 100,000 mg/L	Lab/pilot

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Workflow

Step 1 -- Resolve Intent

User asks about...	Strategy
Treatment for a contaminant	Search TDB by contaminant name
Process comparison	Compare multiple processes for the target contaminant
Produced water treatment train	Recommend multi-step process based on feed chemistry
Removal efficiency data	Look up TDB + supplement with literature values
DLE technology performance	Use reference data table above (not in TDB)
Regulatory BAT	Cross-reference TDB with 40 CFR 435 (O&G effluent guidelines)

Step 2 -- Access EPA TDB

Since there is no REST API, access the web interface:

# Direct the user to the TDB search
echo "Navigate to https://tdb.epa.gov/ and search for your contaminant."
echo "Example: Search 'barium' to see treatment process effectiveness."

For programmatic use, provide the reference data tables above as inline data.

Step 3 -- Supplement with EPA Envirofacts (if needed)

For regulatory data on treatment facilities:

# EPA SDWIS -- treatment techniques at public water systems
curl -s "https://enviro.epa.gov/enviro/efservice/TREATMENT/STATE_CODE/WV/rows/0:10/JSON"

Step 4 -- Produce Output

Format: Treatment Technology Comparison Table + Narrative

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Output Format

## Treatment Technology Comparison: Produced Water from Marcellus Shale

**Feed characteristics (typical):**
- TDS: 100,000-250,000 mg/L
- Li: 50-200 mg/L
- Mg: 500-3,000 mg/L
- Ba: 500-15,000 mg/L
- Oil and Grease: 50-500 mg/L

**Recommended treatment train:**

| Step | Process | Target | Expected Removal |
|------|---------|--------|------------------|
| 1 | Oil/water separation + electrocoag | O&G, TSS | 95-99% O&G |
| 2 | Chemical precipitation (BaSO4) | Ba, Sr, Ra | 95-99% Ba |
| 3 | Li-selective IX (LMO sorbent) | Li recovery | 85-95% Li |
| 4 | NF or softening | Mg, Ca recovery | 85-97% Mg |
| 5 | Evaporation / crystallization | Brine concentration | ZLD |

**Summary:** Marcellus produced water requires a multi-step treatment train
due to extreme TDS (often exceeding 200,000 mg/L) and high barium. Oil
removal must precede any membrane step. Selective lithium recovery via DLE
sorbents should occur before bulk desalination to avoid diluting the Li
stream. Magnesium co-recovery via nanofiltration or selective precipitation
adds economic value.

**Data sources:** EPA Treatability Database (tdb.epa.gov), published DLE
pilot data, SPE produced water treatment literature.

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Error Handling

Issue	Cause	Action
TDB website unavailable	EPA site maintenance	Use reference data tables in this skill as fallback
Contaminant not found in TDB	TDB covers 120+ contaminants but not all	Search by chemical name, CAS number, or related compound
No data for specific treatment + contaminant pair	Not all combinations are in TDB	Note gap; supplement with peer-reviewed literature
DLE technologies not in TDB	TDB focuses on drinking water, not DLE	Use the DLE reference table above; cite primary literature
EPA Envirofacts API error	See pnge-federal-data:epa-regulatory skill for detailed troubleshooting	Check endpoint and parameters

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Caveats

1. No REST API. The EPA TDB is a web-only application. Programmatic bulk data extraction is not supported. The reference tables in this skill provide commonly needed values for offline use.

2. Drinking water focus. The TDB was designed for drinking water treatment, not produced water or industrial brine. Feed water TDS in TDB studies is typically under 5,000 mg/L. Produced water TDS can exceed 300,000 mg/L. Removal efficiency at high TDS may differ significantly.

3. DLE is not covered. Direct lithium extraction technologies (LMO/LTO sorbents, electrochemical methods) are not in the EPA TDB because they are mineral recovery processes, not water treatment. The DLE reference data in this skill comes from published research and pilot studies.

4. Performance depends on feed chemistry. Removal efficiency values are ranges from multiple studies. Actual performance depends on feed water composition, temperature, pH, competing ions, membrane type, resin selection, and operating conditions.

5. Not a design tool. The TDB provides screening-level data for technology selection. Equipment sizing, cost estimation, and process design require detailed engineering analysis with site-specific feed water data.

6. Regulatory context. EPA 40 CFR 435 sets effluent limitations for the oil and gas extraction industry. Onshore unconventional wells generally have zero discharge requirements. The TDB supports technology selection but does not replace regulatory compliance analysis.

7. PFAS coverage. The TDB includes 26 PFAS chemicals as of the latest update. PFAS treatment data is actively expanding but may lag behind current research for newer PFAS compounds.

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Implementation Notes

• Since there is no API, use the inline reference tables for programmatic responses
• Direct users to https://tdb.epa.gov/ for detailed TDB lookups
• For treatment facility data, use the pnge-federal-data:epa-regulatory skill (Envirofacts + ECHO + GHGRP)
• Combine with pnge-core:usgs-produced-waters for feed water characterization
• For DLE technology details, cross-reference with pnge-patents:patentsview and pnge-core:pnge-literature
• Key literature: "Produced Water Treatment" (SPE Monograph), Fakhru'l-Razi et al. (2009) review