Liquid purification or separation – Serially connected distinct treating with or without storage... – With storage unit
Reexamination Certificate
1998-08-17
2001-01-16
Fortuna, Ana (Department: 1723)
Liquid purification or separation
Serially connected distinct treating with or without storage...
With storage unit
C210S258000, C210S097000, C210S134000, C210S104000
Reexamination Certificate
active
06174437
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to water treatment systems of the type utilizing reverse osmosis and/or nano-filtration thin film membrane separation technology.
BACKGROUND
Apparatus for treating water and/or wastewater which utilize conventional membrane separation technology incorporating reverse osmosis and/or nano-filtration thin film membrane separation technology are well known and have been commercially available for many years. One example of an apparatus utilizing conventional membrane separation technology is shown in
FIG. 1
, defined hereafter, and outlined in general terms below.
Conventional membrane separation technology generally incorporates the following processes.
A raw (untreated) water source A is directed to the inlet of the conventional membrane separation device in either a flooded suction condition or under pressure by either a raw feed booster pump or via gravity feed.
A coarse filter B is placed prior to the conventional membrane separation device to separate large solids that might interfere with or damage subsequent pumps and/or membranes.
Pre-treatment apparatus C and devices are then placed to remove dissolved ions, polar contaminates and/or suspended contaminates that might cause damage to, or prevent the efficient operation of, the membrane separator. A partial list of common devices now used with conventional membrane separation technology, chemicals used, costs associated with the pre-treatment devices and the contaminates that they are designed to remove is shown below.
DEVICE
CHEMICALS USED
COSTS
CONTAMINATES REMOVED
MANGANESE GREENS
POTASSIUM PERMANGANATE
MEDIA REPLACEMENT,
IRON, MANGANESE
AND IRON FILTERS
MECHANICAL UP-KEEP
CHEMICAL FEEDS
WATER WASTAGE
ACIDIFICATION
HYDROCHLORIC ACID,
ACID FEED
NONE, ALLOWS OPERATION
SULPHURIC ACID,
MECHANICAL UPKEEP
ON HARD WATER
PHOSPHORIC ACID
CHLORINE/SAND
CHLORINE COMPOUNDS
MECHANICAL UP-KEEP,
IRON, MANGANESE,
FILTRATION IRON FILTERS
MEDIA REPLACEMENT,
BACTERIA, SOME
CHEMICAL FEEDS
ORGANICS
WATER WASTAGE
DECHLORINATION
ACTIVATED CARBON,
MEDIA REPLACEMENT,
CHLORINE, OZONE,
EQUIPMENT
SODIUM THIOSULPHITE FEED
CHEMICAL FEEDS,
SOME ORGANICS
WATER WASTAGE
MECHANICAL UP-KEEP
OZONATION
DESICCANTS, OZONE
DESICCANT UP-KEEP,
IRON, MANGANESE,
MECHANICAL UP-KEEP
SOME ORGANICS, COLOR
OZONE DESTRUCT SYSTEMS
MEDIA SYSTEM
MEDIA REPLACEMENT,
OZONE
MECHANICAL UP-KEEP
SAND FILTERS
NONE
MEDIA REPLACEMENT,
SUSPENDED SOLIDS,
MECHANICAL UP-KEEP
PARTICULATES,
TURBIDITY
WATER SOFTENER
SODIUM CHLORIDE SALT,
SALT FEED,
CALCIUM, MAGNESIUM
ION EXCHANGER
POTASSIUM CHLORIDE SALT
MEDIA REPLACEMENT,
HARDNESS
MECHANICAL UP-KEEP
ORGANIC SCAVAGING
SODIUM CHLORIDE SALT,
SALT FEED,
SOME ORGANICS, SOME
ION EXCHANGER
CAUSTIC SODA
CAUSTIC FEED,
FORMS OF SILICA,
MEDIA REPLACEMENT,
COLOR, SULPHATES
MECHANICAL UP-KEEP
SODA ASH/LIME
SODA ASH,
SODA ASH FEED,
CALCIUM, MAGNESIUM
EXCHANGE SOFTENERS
SODIUM CARBONATE
SODIUM CARBONATE FEED
HARDNESS, SUSPENDED
MECHANICAL UPKEEP
SOLIDS, PARTICULATES,
FILTER BED UPKEEP TURBIDITY
MEDIA REPLACEMENT
Fine polishing filters D, generally of the disposable cartridge type, are provided with smaller systems and/or automated sand filter/coagulant systems are provided with larger systems and follow the pretreatment package. The purpose of this is to provide both filtration to below 15 microns and a silt density index (SDI) of below 5. These are the maximum levels normally acceptable with conventional membrane separation technologies.
A raw feed water shut-off valve E, usually automatic and controlled by the membrane separator device, is normally incorporated in order to prevent raw feed water from entering the membrane separator device when not in operation.
A raw feed water system pressure boost pump F or boost pump set is arranged following the shut-off valve to increase the pressure of the raw feed water to an acceptable level above the osmotic pressure of the raw feed water solution. Operating pressures vary from device to device. In general, the higher the total dissolved solids level of the raw feed water solution to be treated, the higher the operating pressure of the device. Common operating pressures are shown below.
FEED SOLUTION
TOTAL DISSOLVED
TYPICAL
OPERATING
SOLIDS RANGE
PRESSURE RANGE
LOW SALINITY
0 to 1,000 mg/l
60 to 150 psi
SLIGHTLY BRACKISH WATER
1,000 to 5,000 mg/l
150 to 250 psi
MODERATELY BRACKISH
5,000 to 10,000 mg/l
250 to 550 psi
HIGHLY BRACKISH WATER
10,000 to 25,000 mg/l
450 to 850 psi
SEA WATER
25,000 to 38,000 mg/l
800 to 1,150 psi
EXTREME SALINITY
35,000 to 50,000 mg/l
900 to 1,850 psi
As higher operating pressures improve both the product water output of membrane separators operated in the conventional manner and the product water quality, higher pressures than those indicated for the level of dissolved solids present in the raw feed water are sometimes used, but operating at higher pressures results in higher operating costs per volume of product water recovered.
The raw feed water system pressure boost pump or pump set must produce both the pressure required to operate the membrane separator and the required flow as well. Most conventional membrane separator specifications will only allow 10 to 15% recovery of the raw feed water stream if rated membrane service life, final water quality parameters and membrane warranty conditions are to be met. Some conventional membrane separator system designs do not follow these specifications, but this is bad practice.
Pump/motor combinations may include air-cooled motors with positive displacement pumps, single stage centrifugal pumps, or multi-stage centrifugal pumps, or water-cooled submersed motors with multi-staged centrifugal pumps. Average motor efficiencies for these pump designs are as follows.
Air-Cooled Motor, Positive Displacement Pump
55%
Air-Cooled Motor, Centrifugal Pump
60%
Water Cooled, Submersed Motor, Centrifugal Pump
75%
The majority of conventional membrane separator designs operate with air-cooled motors. These are the least efficient and heat generated by the motor is lost to the atmosphere.
In order to meet the membrane separator warranty specifications, the system pressure booster pump/pump set must be capable of producing no less than 8, but preferably 10, times the anticipated flow of final recovered product water. The excess water may be discharged, creating a very water wasteful situation, or be partially recycled. In either case, the raw feed water main drive pump(s) must be capable of pressurizing the same volume of water. This involves considerable horsepower as shown below.
FULL
NO
RECIRCULATION
RECIRCULATION
CONDITION:
SEA WATER,
SEA WATER,
30,000
TDS
30,000
TDS
OPERATION PRESSURE:
850
PSI
850
PSI
REQUIRED PRODUCT
1
USGPM
1
USGPM
WATER FLOW:
REQUIRED MEMBRANE
10
USGPM
10
USGPM
TOTAL:
FEED FLOW
TOTAL MAIN DRIVE
10
USGPM
10
USGPM
PUMP FLOW
RECIRCULATION FLOW:
8
USGPM
0
USGPM
WASTE FLOW:
1
USGPM
9
USGPM
HORSEPOWER FORMULA:
TOTAL
MAIN
DRIVE
×
PRESSURE
PUMP
FLOW
MOTOR
HORSEPOWER
FACTOR
=
THEORETICAL
HORSEPOWER
MOTOR
EFFICIENCY
=
REQUIRED
HORSEPOWER
Therefore, under the above conditions, the horsepower requirements of a membrane separator operating in a conventional manner with an air-cooled motor and centrifugal pump would be:
10
×
850
1560
=
5.45
0.60
=
9.08
Horsepower
Per
Gallon
Per
Minute
Produced
A Membrane Housing G accepts the flow from the raw feed water system pressure booster pump. The typical membrane housing feeds one or more membrane separators H, placed in series, within the housing with raw water from one end only, and in one direction only. The raw feed water is fed directly at the end of the membrane separator placed first within the housing. Brine seals (generally of a “U”-cup design) are placed on each membrane separator element within a series feed housing set, generally at the feed end. The brine seals prevent the flow of raw feed water around the membrane sep
ATP International Ltd.
Fortuna Ana
Pillsbury Madison & Sutro LLP
LandOfFree
Water treatment system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Water treatment system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Water treatment system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2437471