Biosolids Management System Standard · PDF filereinforced per ABS Rules for Building and...
3
12977 Maurer Industrial Dr. Sunset Hills, MO 63127 ph: (314) 756‐9300 fax: (314) 756‐9306 e‐mail: [email protected] web: www.sciencofast.com March 24, 2015, Page 1 of 3 www.sciencofast.com | AffordABLE…AdaptABLE…FAST® 1 Biosolids Management System Standard Specification General Unless otherwise specified, design and construction of MarineFAST® Biosolids Management Systems (BMS) shall follow these guidelines. The unit shall provide aerobic digestion, dewatering, concentration and long term storage of secondary sludge taken from FAST® marine sewage treatment systems that are designed to meet MEPC.159(55) or other secondary treatment requirements. All sewage and sewage sludge will be contained in tanks and piping. Personnel shall not come into contact with sewage or sewage sludge during operation of the BMS. Operation will be automatic and will not require intervention by vessel personnel. Process The sludge will be aerobically digested in the BMS unit. A regenerative turbine blower will transfer oxygen into the tank contents and provide mixing and circulation of the tank contents. The blower will be cycled on and off in order to alternate aerobic and anoxic conditions within the tank. This will stabilize the pH and permit efficient digestion of the sludge. It is important to note the difference here between anoxic and anaerobic conditions. “Anoxic” simply means that the dissolved oxygen in the tank contents will be depleted. At no time will the process create anaerobic conditions resulting in formation of methane or corrosive acids. Settled sludge will be retained for eventual removal and excess water will be returned to the FAST unit for treatment and legal discharge to the sea. Operation of the BMS will not adversely affect the treatment efficiency or the operation of the FAST unit. Operation 1. Sludge from the bottom of the FAST unit media tank will be transferred automatically to the BMS unit. 2. Aeration will transfer oxygen into the tank contents and will also provide circulation so that the process will be completely mixed. 3. Rising water level will actuate a float switch and begin an automatic sequence to separate the digested sludge from excess water. 4. The blower will be shut off to allow the sludge to settle and excess water to rise. 5. A power operated valve will allow the excess water to drain to the supernatant pump wet well. 6. The supernatant pump will automatically return the water to the FAST unit. 7. When the liquid level drops, a second float switch will cause the drain valve to close and the blower will re‐ start. 8. When it is time to empty the accumulated sludge in the BMS tank, it can be discharged to a larger tank, to an offshore supply vessel, to an incinerator or to whatever destination best fits the operation of the vessel or platform. 9. After all connections are made, the pumpout process can be started. When the liquid level drops in the tank, the sludge pump will shut off automatically. 10. If the operator desires to strip the tank before resuming automatic operation, he can do this manually. Operating Limits The BMS will operate under marine vibration and in a seaway with roll angles up to and including ± 30° with 6 second full period. Aerobic digestion is more efficient at warmer water temperatures than at colder temperatures and we
Transcript of Biosolids Management System Standard · PDF filereinforced per ABS Rules for Building and...
12977 Maurer Industrial Dr. Sunset Hills, MO 63127 ph: (314) 756‐9300 fax: (314) 756‐9306
e‐mail: [email protected] web: www.sciencofast.com
March 24, 2015, Page 1 of 3
www.scien
cofast.com | A
ffor
dAB
LE…
Ada
ptA
BLE
…FA
ST®
1
Biosolids Management System
Standard Specification
General
Unless otherwise specified, design and construction of MarineFAST® Biosolids Management Systems (BMS) shall follow these guidelines.
The unit shall provide aerobic digestion, dewatering, concentration and long term storage of secondary sludge taken from FAST® marine sewage treatment systems that are designed to meet MEPC.159(55) or other secondary treatment requirements.
All sewage and sewage sludge will be contained in tanks and piping. Personnel shall not come into contact with sewage or sewage sludge during operation of the BMS.
Operation will be automatic and will not require intervention by vessel personnel.
Process
The sludge will be aerobically digested in the BMS unit. A regenerative turbine blower will transfer oxygen into the tank contents and provide mixing and circulation of the tank contents.
The blower will be cycled on and off in order to alternate aerobic and anoxic conditions within the tank. This will stabilize the pH and permit efficient digestion of the sludge.
It is important to note the difference here between anoxic and anaerobic conditions. “Anoxic” simply means that the dissolved oxygen in the tank contents will be depleted. At no time will the process create anaerobic conditions resulting in formation of methane or corrosive acids.
Settled sludge will be retained for eventual removal and excess water will be returned to the FAST unit for treatment and legal discharge to the sea.
Operation of the BMS will not adversely affect the treatment efficiency or the operation of the FAST unit.
Operation
1. Sludge from the bottom of the FAST unit media tank will be transferred automatically to the BMS unit.
2. Aeration will transfer oxygen into the tank contents and will also provide circulation so that the process will be completely mixed.
3. Rising water level will actuate a float switch and begin an automatic sequence to separate the digested sludge from excess water.
4. The blower will be shut off to allow the sludge to settle and excess water to rise.
5. A power operated valve will allow the excess water to drain to the supernatant pump wet well.
6. The supernatant pump will automatically return the water to the FAST unit.
7. When the liquid level drops, a second float switch will cause the drain valve to close and the blower will re‐start.
8. When it is time to empty the accumulated sludge in the BMS tank, it can be discharged to a larger tank, to an offshore supply vessel, to an incinerator or to whatever destination best fits the operation of the vessel or platform.
9. After all connections are made, the pumpout process can be started. When the liquid level drops in the tank, the sludge pump will shut off automatically.
10. If the operator desires to strip the tank before resuming automatic operation, he can do this manually.
Operating Limits
The BMS will operate under marine vibration and in a seaway with roll angles up to and including ± 30° with 6 second full period.
Aerobic digestion is more efficient at warmer water temperatures than at colder temperatures and we
Scienco/FAST Standard Marine Specification | Sewage Treatment Systems
March 24, 2015, Page 2 of 3
www.scien
cofast.com | A
ffor
dAB
LE…
Ada
ptA
BLE
…FA
ST®
2
recommend installation of the BMS in a heated space, not less than 20° C. But, process efficiency will deteriorate rapidly as water temperature in the BMS increases above 37° C.
Because of the long detention time in the tank (typically six month’s storage), the BMS water temperature will approach the ambient temperature in the space and selection of the space will be an important factor in successful operation. So, it will be best if the BMS is not located in a 50° C. machinery space.
Both the FAST unit and the BMS unit will be fitted with pumps to permit remote installation.
Standard Construction
All equipment shall be in accordance with US Coast Guard requirements for inspected vessels. This includes but is not limited to 46CFR56 Piping Systems and Appurtenances and 46CFR111 Electrical Systems.
Unless otherwise specified, corrosion protection and electrical enclosures will be based upon below deck installation.
Steel Tanks
Welded steel construction shall be employed. Minimum section thickness shall be one‐quarter (1/4) inch and minimum steel specification shall be ASTM A‐36.
Tank penetrations, seams and all other joints shall be full welded both sides all around. All welding shall be per ABS and AWS requirements, and welders shall be certified by AWS. Weld size shall be one‐sixteenth (1/16) inch smaller than the thinner of the two sections being welded.
Bulkheads, tanktops and tank bottoms shall be sized and reinforced per ABS Rules for Building and Classing Steel Vessels, Deep Tanks as applicable. Other structure shall be sized so that maximum stress does not exceed one‐third tensile yield stress for normal operation or two‐thirds tensile yield stress for storm‐sea or other extreme loading conditions.
Protection against Corrosion
Threaded tank penetrations and assembly hardware shall be 316SS. Tanks shall incorporate large access openings for efficient blasting and painting.
Preparation and painting shall be per FAST® Standard Paint Specifications:
1. All steel surfaces shall be grit blasted to SSPC‐SP‐5 white metal with a profile of one and one‐half (1.5) to three (3.0) mils.
2. All internal steel surfaces shall be protected with a two‐coat polyamine epoxy resin coating system (6‐8 mils DFT total). Machinery will be installed with the original manufacturer’s standard coating.
3. For below‐deck installations, all external steel surfaces shall be protected with the same coating system as the
internal surfaces. Machinery will be installed with the original manufacturer’s standard coating.
4. For above‐deck and other installations exposed to sunlight and salt spray, exterior surfaces shall be protected with one coat organic zinc primer (2‐4 mils DFT), two coats polyamine epoxy resin (6‐8 mils DFT total) and one coat urethane (2‐3 mils DFT). Machinery may or may not be provided with an additional coating depending upon the materials of construction.
In general, special exterior coating systems will be quoted individually per the customer’s specifications.
Molded HDPE and XLPE Tanks
If employed, molded tanks shall be high density polyethylene (HDPE) salvage drums meeting US Department of Transportation regulations 49CFR173.3 or shall be cross linked polyethylene (XLPE) overpacks suitable for transporting and storing transformers (PCB’s) per EPA 40CFR761.65. Each polyethylene tank shall be secured to a 304SS steel skid which can be welded or bolted to steel structure.
Aeration System
The system will be fitted with a close‐coupled regenerative turbine blower. It will provide oxygen for aerobic digestion of the sludge.
It will also provide circulation and mixing of the tank contents for efficient treatment during aeration and for efficient removal of sludge during pumpout. The BMS can be vented to weather using the FAST media tank vent and no separate vent should be required.
Transfer Pumps
The system shall incorporate two identical transfer pumps, one to transfer sludge from the FAST media tank to the BMS and one to transfer excess water from the BMS back to the FAST unit for treatment and overboard discharge. These shall be cast iron close‐coupled end‐suction centrifugals with open stainless steel impellers and mechanical seals.
Sludge Pumps
These shall be cast iron close‐coupled solids‐handling trash pumps with open stainless steel impellers and mechanical seals.
Electrical Equipment
IEC blower motors shall be TEFC with IP55 protection. IP65 protection is available for installations exposed to the weather. Pump motors shall be TEFC and may be IEC or NEMA rated.
All motors shall be suitable for continuous operation in 40 C. ambient air temperature. In some cases, motor nameplates
will specify service factors of 1.15 or 1.25 at 40 C. ambient air
Scienco/FAST Standard Marine Specification | Sewage Treatment Systems
March 24, 2015, Page 3 of 3
www.scien
cofast.com | A
ffor
dAB
LE…
Ada
ptA
BLE
…FA
ST®
3
temperature, also suitable for operation at 50 C. ambient with service factor of 1.00.
Motor starters, control panels and junction boxes shall have NEMA 4/4X or IP 55 enclosures as applicable.
Quality Control
All construction, welding, painting, fit and finish shall be first class in every respect. All machinery and equipment shall be new and first class in every respect.
The unit shall be designed for long service life processing seawater sewage sludge in heavy marine or offshore service.
Testing
The Media Tank shall be hydrostatically tested per 33 CFR Part 159 and no leaks are permitted. The blower, pumps and power operated valve shall be operated to confirm proper operation in both automatic and manual modes.
Piping
All customer connections shall be one hundred fifty (150) PSI raised face flanges per ASTM A‐105. Associated piping shall be galvanized carbon steel per ASTM A‐53 Grade B minimum.
Three (3) inch and larger piping shall be welded and flanged and smaller piping may be threaded. Pipe and fittings on the unit may be galvanized steel, 316SS, CPVC or PVC specific to the application in each case. When used, non‐metallic piping shall meet applicable ASTM standards and USCG flame‐spread requirements.
When specified, stainless steel piping shall be per ASTM A‐312, ASTM 376 and MIL‐P‐1144. In general 316SS will be used for exposure to seawater and salt spray. All customer connections shall be one hundred fifty (150) PSI raised face flanges, and all stainless steel flanges and fittings shall be dimensionally identical to carbon steel fittings of corresponding pipe size and schedule.
Valves
In general, 316SS or bronze valves shall be used with galvanized steel piping and PVC valves will be used with PVC or CPVC piping. For galvanized and 316SS piping, all valves other than LX‐Series, valves shall be rated for one hundred fifty (150) PSI service and as specified below:
1. Ball valves shall be Sharpe 50M76 Threaded Full Port Ball Valve or equal, incorporate two piece body, blowout proof stem, PTFE seats and full ports. Body, cap, ball and stem shall be 316SS.
2. Globe valves shall be Sharpe 40276 Threaded Globe Valve or equal, inside screw and screwed bonnet, rising stem. Body, disk, stem and packing nut shall be 316SS.
3. Check valves shall be Sharpe 20276 threaded or equal, horizontal swing, screwed cap, integral seats. Cover, pin nut, disc and body shall be 316SS.
4. Butterfly valves shall be NIBCO WD2000 or equal. They shall incorporate ductile iron body, extended neck, geometric drive, molded‐in seat liner, shall be of the wafer type and shall conform to MSS‐SP67, MSS‐SP25 and API‐609.
Gages
If used, gages reading 15 psi or greater shall be Winters LF Series, 2‐1/2” dial size, liquid filled, 1.6% accuracy, with brass internals and 304SS case.
If used, gages reading lower pressures shall be Winters Low Pressure, 2‐1/2” dial size, 1% accuracy, with brass internals, black steel case and restrictor screw.
Documentation
Documentation shall include three (3) sets Installation Drawings per order and Three (3) each Operating Instruction Manuals per unit. An additional set of Installation Drawings will be included in each Operating Instruction Manual.
Installation Drawings and Operating Instruction Manuals shall include original manufacturers’ part numbers, source information and instruction manual inserts as applicable for machinery, valves and controls. Drawings and manuals shall be of commercial marine quality.
Detail design calculations, manufacturing drawings and associated bills of materials will not be provided. The design is proprietary and details are only disclosed to regulatory authorities.
Changes
It is understood that specific applications may require other material selections and piping methods. Scienco/FAST® reserves the right to change these specifications at any time.
Scienco/FAST Division
12977 Maurer Industrial Dr.
Sunset Hills, MO 63127‐1515
p: (314)645‐6540, f: (314)645‐6131
Email: [email protected]
web: www.sciencofast.com
