Reverse Osmosis Water Treatment
Timothy English II
Overview
Overview of Reverse Osmosis
Brackish RO Characteristics
Case Study
Membrane Processes
Separation Process
Suspended Solids
Microfiltration
Ultrafiltration
Nanofiltration
Reverse Osmosis
Dissolved Constituents
Membrane Removal
Typical RO Finished Water Quality
Parameter
Percent Removal
Turbidity
~100
TDS
90-99
TOC
90-99
Chlorides
90-99
Color
95-99
Iron & Manganese
~100
Reverse Osmosis System
Pretreatment
Addition of Acid
Used to prevent calcium carbonate
precipitation
Sulfuric Acid (most common)
Addition of Antiscalant
Used to prevent precipitation of other salts
Low dose: < 3-4 mg/L
Cartridge Filtration
Final suspended solids barrier before
membrane treatment
“Safety Net” to prevent membrane damage
Cartridge Filters
Reverse Osmosis Skid
Membrane Components
Pressure Vessels
Membrane Elements
Controls
Sampling Taps
Products
Permeate: Treated water sent to posttreatment and distribution
Concentrate: Residual stream sent to
disposal site
Membrane Selection
Projection Software Provided by
Membrane Element Manufacture
Membrane Configuration
Permeate and Concentrate Water Quality
Feed Pressure
Piloting
Test Equipment without the Capital
Expense
Confirm and Optimize Performance and
Processes
Projection Software
Piloting
High Pressure Feed Pumps
Reverse Osmosis Skids
Brackish RO Performance
Operation
100-300 psi Feed Pressure
< 85% Recovery
Permeate Water Quality
TDS < 50 ppm
Hardness < 5 ppm as CaCO3
TOC < 0.5 ppm => Low Disinfection
Byproducts
Low Alkalinity
Permeate Post-Treatment
Permeate is Aggressive
Low pH
Lack of Calcium
Low Alkalinity
Corrosion Control
CO2 Degasification
Lime
Caustic
Calcium Chloride
Blend Water
Raw Brackish Water
Small Blend Ratio
TOC/DBP Concerns
Fresh Brackish Water
Limited Availability
Pretreatment and TOC/DBP
Reduces Energy Consumption and
Concentrate Volume
Concentrate Water Quality
Source
Feed TDS
(mg/L)
Water
Recovery
(%)
Residual TDS (mg/L)
Surface
Water
200
85
1,330
Fresh
Groundwater
400
85
2,660
Brackish
Groundwater
2,000
75
8,000
Seawater
32,000
50
64,000
Concentrate Disposal
Surface Water Discharge
Subsurface Injection
Sanitary Sewer
Evaporation Pond
Reuse
Irrigation
Land Application
Percolation Ponds
Dewatering / Zero Discharge
Case Study
RO Treatment to Meet Primary and
Secondary Standards
Pressure: ~150 psi
TDS < 100 ppm
Cl < 50 ppm
Hardness < 10 ppm
Permeate is Blended with Fresh
Groundwater prior to Post-Treatment
Concentrate Disposal via Deep Well
Injection
Case Study
Thank You!
Questions?
1016 Spring Villas Point
Winter Springs, FL 32708
[email protected]