Water Recycling the expensive way

PRODUCED WATER TREATMENT

Shale Gas in North America

Shale Gas Formations

• Generally the shale formations in eastern US are dry.

• The produced water (Flow Back) is very salty –TDS 100,000 to 200,000 ppm.

• In the western states the produced water is • In the western states the produced water is much lower in TDS – 10,000 to 35,000 ppm.

• However, the shale is wet and a typical well will produce 100 to 200 bls/day for the life of the well.

CHARACTERISTICS OF

PRODUCED WATER

Produced Water Management

Requires a Customized Approach

• Produced water characteristics and flows depend on:– Geographic location

– Geological formation

– Type of hydrocarbon being produced

– Lifetime of the reservoir

– Well operations (chemicals used)

• Main parameters needed to engineer a solution are:• Main parameters needed to engineer a solution are:– Produced water flow rates

– TSS and O&G concentration

– TDS concentration

– TOC concentration and its nature (PAH, Phenols, BTEX, etc…)

– Metal concentrations

– Final treated water destination (discharge or reuse)

VEOLIA PRODUCED WATER

TREATMENT SOLUTIONS

Treatment Solutions depend on final

use of the treated water

• Reuse for reinjection purposes

• Reuse as Boiler Feed Water

• Discharge into surface water bodies• Discharge into surface water bodies

• Surface Irrigation

� Due to the high salinity of the Produced Water almost all treatment solutions require the use of either Evaporation or Reverse Osmosis.

Flow Back and Produced Water from

Deposits in Eastern United States

• Is generally substantially less than the amount

of water used to frac the well.

• Very high TDS.

• Can be used to frac the next well to be drilled.• Can be used to frac the next well to be drilled.

• Scaling compounds – hardness and barium

can be removed by lime softening.

• Can be treated for disposal by evaporation

and crystallization.

Multiflo Lime Softener

Typical Evaporators

Brine Evaporator ZLD mode

Feed

Chemicals

Deaerator Brine

Evaporator

NCG Vent

Compression

Device

Feed Tank

Recovered

Water

Feed

Preheater

Recirculation

Pump

Seed

Recycle

Level

Tank

Concentrated Brine

ZLD pilot testing (Marcellus)

• Marcellus shale produced water

Brine crystallizer systems

Capacities ranging from 50 to greater than 1,200 gpm

180,000 ppm TDS in produced water

Result: Salt able to be landfilled

Flow Back and Produced Water from

Deposits in Western United States

• Is generally substantially more than the

amount of water used to frac the well.

• TDS: 10,000 – 35,000 ppm

• Can be treated by Reverse Osmosis (RO) and • Can be treated by Reverse Osmosis (RO) and

used as drilling mud, frac water or be

discharged to the environment.

• Reject from RO can be treated for disposal by

evaporation and crystallization.

Reverse Osmosis can:

• Produce product water suitable for frac water, drilling mud or discharge to the environment.

• RO reject water (brine) can be evaporated in ponds, deep well injected or evaporated and crystallized in equipment designed for that propose. Approx 10 – 25% of the total influent flow.of the total influent flow.

Reverse Osmosis cannot:

• Tolerate any Free Oil & Grease in the feed water: this would create fouling problems

• Tolerate high COD concentrations (8000mg/l max if pH>10, 350 mg/l max if 6<pH<9.5) in the reject: this would create fouling problems and organics breakthrough in the permeate

• Tolerate any hardness and alkalinity in the feed water if • Tolerate any hardness and alkalinity in the feed water if RO runs at high pH (>10): this would create scaling problems

Example of RO System

Produced Water Contains Organics

• BTEX

• Aliphatic Hydrocarbons (Hexane Extractables - FOG)

• Poly Aromatic Hydrocarbons (PAH)

• Alcohols, ethers, ketones and phenols• Alcohols, ethers, ketones and phenols

• Low molecular weight organic acids

• High molecular weight organic acids

High Molecular Weight Organic Acids are

the Problem:

• Typically they are very weak acids and do not ionize well at neutral pH.

• The molecular weight range allows them to pass though a UF membrane, but not though an RO membrane.though a UF membrane, but not though an RO membrane.

• They are not very soluble in water – as the concentrate up in the RO reject they precipitate on the membrane and foul the surface.

Methods to pretreat PW for RO feed

• Remove the free oil and solubilize the organic

acids by raising the pH of the RO Feed – OPUS™.

– Requires all free oil to be removed.

– Requires all of the hardness to be removed.

– Requires most of the alkalinity be removed.

• Remove the organics from the RO feed – MPPE® &

NEOSEP® MBR.

– BTEX, PAH, and most biotoxic compounds can be removed with

the MPPE® process.

– The water is then treated with aerobic bacteria and ultra filtered .

OPUS TECHNOLOGY

HIGH PH RO

OPUS™ Technology

OPUS - II - Next Generation Product

OPUS™ Technology - Applicability

• When high water recovery rates are specified.

• When the quality of the treated effluent has to meet stringent limits (when OPUS is coupled with IX Ammonia removal and chemical oxidation of the permeate).

• When the COD present in the raw influent is mostly non-biodegradable (BOD5/COD < 0.2).

• When the COD concentration in the reject is not too high (< 8000 mg/l: this means a COD in the raw influent of about 1000 – 2000 mg/l depending on the recovery rate).mg/l: this means a COD in the raw influent of about 1000 – 2000 mg/l depending on the recovery rate).

• When the Hardness concentration in the raw influent is not too high (<250 mg/l).

• When TDS < 30,000 mg/l (above this value evaporation is recommended if a high quality permeate is needed).

• In ZLD applications combined with a reject crystallizer.

OPUS - Chemicals, Utilities

consumption and Waste generationParameter

Hydrated Lime

Caustic

Soda Ash

Polymer

Coagulant

Acids

Value (mg / liter of raw influent)

250

200

1300

1.5

5

1000Acids

Salt

Sludge generated (85% chemical)

H2O2

Power

Reject to injection well or evaporation

pond or crystallizer

1000

4000

50% dry solids after dewatering: 3000 mg of wet sludge / liter of raw influent

15

513 kWh/kbl.

~ 20% of raw influent flow

OPUS™ Technology - Benefits

• High “System” Recovery Rates

– 70 - 90%+ depending on TDS

• Effective Fouling Control

– Bio-Fouling, Organic Fouling, Particulate Fouling

• Effective Scaling Control

– Silica, Calcium Salts, Metal Salts

• Ability to Handle Variations in Feed Water Quality• Ability to Handle Variations in Feed Water Quality

– TSS, Total Hardness, Silica, etc

• High Salt Rejection

– Silica > 99.9%, Boron > 99.4%, TOC > 99%

• No need for biological system – Low risk of process upsets even

in presence of shock loads or toxics

• Reliable Operation with Minimal Downtime

Chevron, San Ardo, CA

MPPE + MBR + RO

ORGANIC REMOVAL BEFORE ROORGANIC REMOVAL BEFORE RO

MPPE & MBR System

MPPE process

MPPE effect on chemical compositionCompounds ppm CompositionDispersed oil =

Dispersed hydrocarbons =

Dispersed Aliphatics = floating

Toxic:

- Benzene

- Toluene

- Ethyl benzene

Dissolved hydrocarbons

40 - > 100

100 - 800 B

T

E

DA

Aromatics

B

E

MPPE

- Xylene

- PAHs and NPDs

- Alkyl Phenols

0.2 - 6

0.1 - 0.2

100

Dissolved hydrocarbons

Readily Biodegradable

Polar:

- Acids

- Alcohols (Methanol)

PAHs

Polar

A Ph

E

X

Polar

E

X

Polar

PAHs

1000

MPPE demo unit

MPPE + MBR + RO Process - Applicability

• When high water recovery rates are specified

• When the quality of the treated effluent has to meet stringent limits

• When the raw influent COD concentration is > 1500 mg/l and the BOD5/COD > 0.2 (COD is biodegradable)

• When TDS < 30,000 mg/l (above this value evaporation is recommended)

• When a lower COD reject stream needs to be generated• When a lower COD reject stream needs to be generated

• In ZLD applications combined with a reject crystallizer

• When low molecular weight organics are present in high concentrations (benzene, methanol, etc…)

MPPE+MBR+RO - Chemicals, Utilities

consumption and Waste generation

Parameter

Polymer

Coagulant

Phosphoric Acid

Sludge generated (80% biological)

Value (mg / liter of raw influent)

0 - 10

5

5

900 (consider 20% dry solids afterSludge generated (80% biological)

Low Pressure Steam

Power

Reject to injection well or

evaporation pond or crystallizer

900 (consider 20% dry solids after

dewatering: 4500 mg of wet sludge / liter

of raw influent)

0.07 kg/bbl

770 kWh/kbbl

~ 20% of raw influent flow

MPPE + MBR + RO Process - Benefits• No need for hardness removal upfront

• MPPE can remove, BTEX, Bio-toxics and many Refractory Organics.

• MPPE can remove both dispersed and dissolved hydrocarbons.

• The extracted hydrocarbons are recovered as oil –not sludge.

• Bacteria can cheaply oxidize most of the soluble • Bacteria can cheaply oxidize most of the soluble organic compounds (COD) to carbon dioxide.

• RO membranes last longer.

• RO feed has lower membrane fouling tendencies.

• Lower risks of organics or ammonia leakage through the membranes.

• RO reject contains lower COD concentrations.

Submerged

Ultrafiltration

Reverse

Osmosis

Biotreater

Zero Liquid Discharge System

Evaporation

MPPE Units at Pluto gas fieldBurrup LNG park, Australia

22/08/2011 3

7

DBO approximate costs per barrel of

Raw Produced Water Treated over 18

years

TECHNOLOGY

On site Evaporation (mobile units)

Cost ($/bbl)

3 - 4On site Evaporation (mobile units)

On site RO based process

(Deoling + OPUS or Deoling+ MPPE+MBR+RO)

Off site Crystallization

3 - 4

2 - 3

4 - 5