Applying Membranes to Produced Wate

HIGH RECOVERY REVERSE OSMOSIS TREATMENT PRO

November 2008
U.S. Natural Gas Production, Consumption, 

1970-2020 (trillion cubic feet)

Source: ALL Consulting. Handbook on Coal Bed Methane Produced Water: Management and Beneficial Use Alternatives, July 

Major Ne-CBNG-Tight Sa-Shale
Along with the gas comes water:

typical water production in a CBNG field

-20

406080

100120140160180

Jan99 Jan- 00 Jan- 01 Jan- 02 Jan- 03 Jan- 04 Jan- 05 Jan- 06 Jan- 07 Jan- 08 Jan- 09 Jan- 10 Jan- 11 Jan- 12 Jan- 13 Jan- 14 Jan- 15 Jan- 16 

Water Production (MBWPD) 
Along with the water come the water i

High volumes of produced water that decrease Elevated concentrations of dissolved salts (sodSuspended solids from well development and p

wells

Limited disposal optionsIncreased regulations
Pressure from

Regulators,

Landowners,

and Public

Along with the water issues come regulator

perceptions and concerns:

Historical Produced Water Management: – Deep well 

injection – Direct discharge – Impoundments – Irrigation – Treatment and discharge

CurrFutuWate

– T

d

– M– R

sa

– D

in

– L– “G

do
Produced Water Production Optio

and Costs

Direct 

Discharge

Passive Treatment 

and Discharge Irrigation Impound- ment 

Rigorous Treatment

COST ($/per barrel)

$0.03-$0.05/bbl

$0.04-$0.06/bbl

$0.10-$0.16/bbl

$0.12-$0.18/bbl

$0.25-$2.00/bbl
Key Water Management Concerns:

Water resource concernsSurface water quality impactsShallow groundwater quality impactsLong-term soil damage from salinity and sodicit

BOTTOM LINE: 

Huge CBM resources are driving developmentWater quality concerns driving toward more treaWater resource issues handled under water rig
20,000

Produced Water Quality / Basin

Binko, K.L. and Drewes, J.E., 2008, Environmental Engineering Science, Produced W
Dominant Salts in Produced Water By Basi
Water Treatment Objectives and Tech

Basin-Wide Objectives:TDS Removal (soluble sodium salts)Minimize brine disposalMeet stringent discharge criteria for TDS (EC)Cost-effective

Key Treatment Technologies: Elements of each ar

to meet future objectives!

Ion ExchangeReverse OsmosisMechanical Evaporation
RO Membrane Separation Mechan

Feed

Flow

H

2

O

H

2

O

H

2

O

H

2

O Mg

Cl

Fe

++

HCO

3 Ca

Na

+ SO

4

++

++

Pressure

H

2

O

H

2

O

H

2

O

H

2

O

H

2

O

H

2

O

Permeate
Severe fouling results in RO membranes that 
 RO membranes are designed for a very spe

purpose: to separate dissolved solutes from  RO is a “non-selective” treatment process: 

rejected, depending on their mass transport 

 RO concentrates simultaneously as it puri

 Other constituents of the feed water can in

this separation and make the process ineffici

 The deposition of material on the membran

that impedes the design production and qual

permeate has to be avoided.

Successful RO systems need effective process step(s) i

membrane unit to remove or minimize the presence of cfeed that can inhibit membrane functionality. Effective pretreatment makes it work by limiting the fouthe feed water.

What do we need to remember when we h

membrane system?
Key to Success: Efficient Pretreatm

Pretreatment Steps:Particulate removal (coal fines, clay, etc.)Hardness and metals removalBacteria controlOther: Oil and grease, VOC’s, etc.

Pretreatment steps allow silica to be concen

much higher levels without precipitation

The result is an RO process operation at high wa

with minimal potential for membrane fou
CDM’s Produced Water Technology So

Developed over several years in response to inEfficient combination of all three key treatment 

IX, RO and Evaporation

Bench and pilot tested Completed intensive internal technical review pPatent pending process: “Method and Apparatu

Recovery of Water Containing Silica”
How it Works:

High 

Pressure RO

Evaporator

(Optional)

Scale Inhibitor/Dispersant (3-7 ppm)

Natural Gas/Waste Heat

HCl

(intermittent, 

low volume)

D

Pe

Pe

ProducedWater

Reject

Reject

Calcium/Magnesium Chloride Soluti

RO Perm

Advanced 

Filtration

UV 

Oxidation

Low 

Pressure RO

WAC Water

Softener

Filter BW

 Keep produced water anaerobic Filter colloidal material effectively Remove polyvalent cations that form 

fouling compounds as they are concentrated

 Concentrate monovalent ionic species Evaporate residual 
CDM High Recovery RO Treatment P

How it Looks:

Microfiltration 

Skids

WAC 

Softeners

UV, C

F

Pum
Pilot Test – Powder River Basin
Pilot Test Results

Treated > 3M gallons at 97% recoveryTreated >500,000 gallons at 98% recoveryHigh product water quality (EC < 400 mS/cm)UV disinfection reduced bacteriaWAC softening excellent: <0.1 mg/L TH as CaC

consistently achieved with no regeneration oveperiod. 

Overall recovery limited by sodium bicarbonate 

(8.5% wt) at the feed conditions

Identified filtration as key step! Incoming TSS w

advertised.
Evaporator 

Concentrate

Sodium Carbonate Byproduct
CASE STUDY #1:

Coalbed Natural Gas Powder River Basin in Monta
Feed Quality and Effluen

Parameter Feed Efflue

Targe

Conductivity 2,933 <1,00Hardness (CaCO

3) 33

Sodium 787Bicarbonate 2,047Total Nitrogen 2.0 1.1SAR 61 <3

All values in mg/L

Case Study @ PRB
Project Specifics

Modular Flow Increments: 5-10,000 bbl/d every Final Design Flow: 35,000 bbl/day Design/Build/Own/OperateIncludes Brine DisposalLong-term Operating Contract

Case Study @ PRB
Comparison to IX Techn

Basis: 35,000 bbl/d Feed at EC: 2,900Treatment to EC: 1,000, SAR: 3

Performance 

Parameter

CDM RO Process 

with ZLD

Cu

Tec

Overall Recovery 100% Bypass of Untreated Water 0% Effluent Electrical Conductivity (EC) 235 

μS/cm 1,0

Off-Site Brine Disposal 0 bbl/wk 4,8Brine Composition Sodium Bicarbonate (97% Pure) Sodiu

Gypsum Addition for SAR Adjustment 0 tons/yr 86

Acid Consumption (32% HCl) <750 gal/wk 40,0

Case Study @ PRB
Projected Cost for CDM Pro

35,000 bbl/d

Treatment Costs: $0.14/bbl

• Includes all Equipment, Consumables and Operations• Does not include power, gas

Brine Disposal Costs:

1) Sheridan Commercial Disposal Well: $0.18/2) Evaporator Alternative: $0.08/bbl

– $2.25 million equipment– Estimated costs includes capital &O&M– Does not include gas– 75% volume reduction (75% of the 3% residual fr

Total Projected Cost: $0.22 to $0.32/bbl

Case Study @ PRB
CASE STUDY #

Tight Sand GasPiceance BasinColorado
Feed Quality and Effluen

Parameter Feed Efflue

Targe

TDS 11,215 <500Hardness (CaCO

3) 213

Sodium 4,036Bicarbonate 2,059Chloride 5,202Sulfate 21Oil/Grease 438 <10Silica 119

All values in mg/L

Case Study @ Piceance
Project Specifics

Design/Build/Own/Operate90% Reduction in VolumeDoesn’t Include Brine DisposalLimited Space for PondsTotal Flow: 20,000 bbl/day 5+ Year Contract

Case Study @ Piceance
CDM Treatment Proces

Lime

Distillat

Perm

ProducedWater

H Gas Reject

2SO4

Oil

MgSO4

DGF CDM Process Solids Contact Clarifier

Evaporator

(Optional)

Filter

Press

Case Study @ Piceance
Performance and Cost S

Effluent TDS: 478 mg/LRecovery: 90% (1,200 psig)Meets all other target standardsBy-products:

– Oil: 10 bbl/d– Lime Sludge: 4.5 wet tons/d

Chemical Usage (for added steps):

– Sulfuric Acid: 0.4 lbs/bbl– Magnesium Sulfate: 0.15 lbs/bbl– Lime: 0.084 lbs/bbl

Cost: $1.65 – 1.95/bbl

Case Study @ Piceance
Questions & Answers

 Cost-effective with water 

recoveries up to 97 – 98%

 Little chemical addition 

required; continuous or intermittent

 Minimal membrane fouling High quality effluent that 

can meet current and future regulatory standards

 Modular system 

configurations

 Broad application across 

basins