PART 1 - GENERAL

1.1 Scope: The work covered in this section includes furnishing all labor, material, equipment and incidents to install complete and ready for operation, a polymer feed system device as shown on drawings and as specified herein.

1.2 APPLICABLE PUBLICATIONS: The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by the basic designation only.

American National Standards Institute (ANSI) Publication:

Pipe Flanges and Flanged Fittings, Class 25, 125, 250 and 800

American Society for Testing and Materials (ASTM) Publications:

ASTM D 1785 Polyvinyl Chloride (PVC) Plastic Pipe, Schedules 40, 80, and 120
A-240 304L Stainless Steel Plate
A-249 Stainless Tubing
A-276 304L Stainless Rounds, Squares, Flats

1.3 SUBMITTALS:

1.3.1 Contracting officer will review and approve all submittals.

1.3.2. Submit the following before fabrication

1.3.2.1 Shop Drawings: Shop drawings for polymer feed system and accessory equipment including principle dimensions and location of fittings.

1.3.2.2 Calculations to prove that the mixing turbulence is at least G=10,000 sec^-1 as well as calculations to prove that the aging chamber is non-turbulent and not mechanically agitated.

1.3.2.3 Calculations to prove the mechanical mixing section does not exceed 30 seconds plug flow at a flow rate of 1.5 gallons per minute.

1.3.2.4 Calculations to prove that the non-turbulent aging chamber has a plug flow retention time of 10 minutes at a flow rate of 1.5 gallons per minute.

1.3.2.5 Design details proving the diluted polymer is not subjected to mechanical agitation after leaving the initial high turbulent mixing section.

1.4 DELIVERY, STORAGE, AND HANDLING MATERIALS:

1.4.1 Delivery and Storage: Inspect materials delivered to site for damage; unload and store with minimum handling. Store materials on site in enclosures or under protective coverings. Protect materials not suitable for outdoor storage to prevent damage during periods of inclement weather, including subfreezing temperatures, precipitation, and high winds. Store materials susceptible to deterioration by direct sunlight under cover and avoid damage due to high temperatures. Do not store materials on ground. Store and protect materials according to manufacturer recommendations.

1.4.2 Handling: Handle polymer feed system in such a manner as to ensure delivery to final location in sound, undamaged condition. Take special care not to damage surfaces of the polymer feed system. Make satisfactory repairs to damaged material(s) at no cost. Carry and do not drag materials. Handle polymer feed system according to manufacturers information.

1.5 QUALITY ASSURANCE:

1.5.1 Inspection: Examine each component of polymer feed system for compliance with requirements specified. Redesign or modification of equipment to comply with specified requirements, or necessary redesign or modification following failure to meet specified requirements, shall receive particular attention for adequacy and suitability. This element of inspection shall encompass visual examinations and dimensional measurements. Noncompliance with specified requirements, or presence of one or more defects preventing or lessening maximum efficiency of polymer feed system operation, shall constitute cause for rejection.

PART 2 - POLYMER FEED SYSTEM DESIGN CRITERIA AND MANUFACTURING SPECIFICATIONS

2.1 POLYMER FEED SYSTEM - APPLICATIONS & PERFORMANCE

2.1.1 Applications: The automated polymer dilution/feed system shall consist of an integrated equipment package capable of automatically metering, diluting, aging, activating, and pumping liquid polymer and water. After leaving the initial mixing chamber, the polymer solution shall pass through a non turbulent aging chamber. After initial dilution, the dispersed polymer in water shall not be subjected to shear.

2.1.2 Performance: The system shall have the capability of handling emulsion and solution polyelectrolytes. The system shall be designed to mix a 20 - 50 percent concentrated liquid polymer solution with viscosities up to 60,000 CPS with water, automatically produce a diluted and aged polymer solution and to convey the aged polymer solution to the application point. The system shall be an integrated package, prepiped, and prewired. The configuration shall provide for a complete integral polymer feed system, mixing and aging the polymer, and occupying the smallest possible space. The feed system input range shall be up to   A*   USGPH dilution water and up to   B*   USGPH polymer.

2.2 POLYMER FEED SYSTEM - Manufacturing specification

2.2.1 Mixing Requirements: Mixing energy shall be provided by a motor driven stainless steel multi-bladed impeller. Mixing chamber impeller shall be powered by a heavy duty direct drive 1725 rpm motor of at least 3/4 HP with manually resettable thermal overload protection; belt drives and static mixers shall not be acceptable. Impeller shall rotate on a stainless steel shaft supported by stainless steel bearings and seals. Mixing chamber shall be transparent acrylic and shall be capable of 100 psig working pressure.

To prevent vortexing and induce uniform back mixing throughout, the mixing chamber shall contain at least four (4) stainless steel baffles rigidly mounted near the mixing chamber’s internal wall.

The polymer mixing/dilution chamber shall provide high speed high turbulent mixing conditions for a short period to rapidly disperse the polymer, then to prohibit the destruction of the fragile long chained freshly activated polymer, the polymer solution shall not be subjected to mechanical agitation in the aging chamber.

Per the Camp-Steen equation, the mixing chamber will have a minimum turbulence of G=10,000 sec^-1.

The retention time in the mixing chamber shall not exceed 30 seconds at a flow rate of 1.5 gallons per minute.

Polymer mixing system shall be specifically designed to invert, disperse, age, and activate solution, emulsion and dispersion polymers with viscosities from 200 - 60,000 CPS.

2.2.2 Aging Chamber: A non-turbulent aging chamber shall form the base of the polymer mixing device with the high turbulent mixing chamber integrally attached to the top of the aging chamber. The aging chamber shall not be subjected to any mechanical agitation and shall be of non-metallic construction. The aging chamber shall have PVC internal baffles to prohibit channeling or short circuit flows.

The aging chamber shall provide a retention time of at least 10 minutes at a flow rate of 1.5 gallons per minute.

2.2.3 Water Flow: The system shall have a switch to shut power off to the unit in case of low water pressure, an electrically operated solenoid valve for on/off control of dilution water supply, and a rotameter type indicator equipped with an integral rate adjusting valve. The flow indicator shall have a valve stop and guided float. Water flow rate shall be adjustable to   A*   USGPH. Water supply input shall be   C*   " FNPT and stock solution outlet fitting shall be   D*   " FNPT. Polymer feed system shall be capable of operating with a water supply pressure of 30 PSIG.

2.2.4 Controls and Metering Pump: Components shall include but not be limited to: solenoid valve and rotameter with rate valve on water; water pressure regulator, and metering pump.

Metering pump shall have a variable stroke rate and stroke length. Output volume shall be adjustable while pump is in operation.

Metering pump shall be of the electronic solenoid operated type. Pump shall be positive displacement with no mechanical linkage. Power supply will be 115 volt, 60 Hz.

OPTIONAL 2.2.5 (Slave Pump) Metering Pump 4-20 mA Controllable: Metering pump shall be upgraded to a model that is controllable by means of either a 4 - 20 mA signal or manual control to automatically proportion the polymer.

OPTIONAL 2.2.6 (Smart Pump) Low Flow Shutoff Switch: A low flow shutoff switch is available as a replacement to the standard low pressure shutoff switch. This option would be useful should the solution flow exiting the polymer system be blocked (by a valve down stream being in the wrong position).

OPTIONAL 2.2.7 Calibration Tube Assembly: The calibration tube assembly is an 8 oz. tube mounted to the side of the aging chamber that tees into the polymer line leading to the metering pump. The standpipe shall allow convenient observation of maximum speed settings. The tube is used to isolate a precise amount of polymer (8 oz.), allowing for observation of seconds elapsed during use of the precise amount. With this information, the operator can calculate gph of polymer use and, with knowledge of the wastewater stream flow, can also calculate dosage in ppm.

2.3 CONTROL PANEL

2.3.1 Central Controls: The central controls shall be housed in a NEMA 4 enclosure. Controls requiring operator adjustment shall be surface mounted. Control panel shall be mounted on the polymer mixing and aging unit.

2.4 TESTING

2.4.1 The entire unit shall be shop hydrostatically tested. Documentation of hydrostatic test shall be provided.

PART 3 - DELIVERY, STORAGE AND HANDLING MATERIALS

3.1 Delivery and Storage: Inspect materials delivered to site for damage; unload and store with minimum handling. Store materials on-site in enclosures or under protective coverings. Protect materials not suitable for outdoor storage to prevent damage during periods of inclement weather, including subfreezing temperatures, precipitation and high winds. Store material susceptible to deterioration by direct sunlight under cover and avoid damage due to high temperatures. Do not store materials directly on ground. If special precautions are required, prominently and legibly stencil instruction for such precautions on outside of equipment or its crating. Store and protect materials according to manufacturers recommendations.

3.2 Handling: Handle polymer feed system in such a manner as to ensure delivery to final location in sound, undamaged condition. Take special care not to damage surfaces of polymer feed system. Make satisfactory repairs to damaged material(s) at no cost. Carry and do not drag materials. Handle polymer feed system according to manufacturers information.

PART 4 - EXECUTION

4.1 Installation: Polymer feed system to be installed as indicated and as recommended by the manufacturer. Equipment delivered to the site in advance of installation to be stored per the manufacturer’s requirements. Make all connections as required to make polymer feed system fully operational.

PART 5 - SUGGESTED MANUFACTURER:

The polymer feed system shall be model number #   *   manufactured by:

Hoffland Environmental, Inc.
10391 Silver Springs Road
Conroe, Texas 77303-1602

(936) 856-4515 phone / (936) 856-4589 fax
e-mail: hoffland@flex.net

*Model Number   *