Unless otherwise specified, design and construction of standard marine sewage treatment units shall follow these guidelines.
The unit shall employ Fixed Activated Sludge Treatment (FAST®) as designed and manufactured by Scienco/FAST Division, Bio-Microbics, Inc. Microbes normally present in human waste shall site naturally on fixed media and use incoming sewage as food. A blower and airlift(s) shall transfer oxygen into the water, circulate the contents and maintain aerobic conditions.
Unless otherwise specified, disinfection shall employ (a) calcium hypochlorite tablets with a suitable tablet feeder or (b) sodium hypochlorite laundry bleach with a suitable chemical pump to provide proportional chlorination. When required, dechlorination shall be provided using corresponding means.
The chlorine contact tank shall provide not less than fifteen (15) minutes detention time at peak hourly flow to ensure efficient disinfection. If applicable, the dechlorination contactor shall provide not less than thirty (30) seconds detention time so that effluent total available chlorine is within specified limits.
33 CFR Part 159
The unit shall be labeled as a Type II USCG certified marine sanitation device per 33 CFR Part 159 for use aboard USCG inspected vessels. That is, all FAST units comply with applicable requirements of USCG electrical and piping regulations 46 CFR Part 111 and 46 CFR Part 56 respectively.
If so specified, the unit shall be certified under MEPC.159(55) for USCG inspected vessels as specified in USCG Navigation and Vessel Inspection Circular NVIC 01-09 Voluntary Compliance with International Sewage Regulations in Annex IV to MARPOL 73/78.
If secondary treatment is specified and unless otherwise specified, then in addition to the above, at any loading up to and including Rated Capacity, at any flow up to and including Maximum Hydraulic Capacity and based upon a thirty (30) day composite average:
- The system will be designed to remove not less than eighty five percent (85%) of all applied BOD5 and suspended solids.
- The system shall be designed to produce effluent containing not more than thirty (30) MG/L BOD5 and thirty (30) MG/L suspended solids.
If other effluent standards are specified, then the system will be designed to meet those standards.
Unless otherwise specified, the equipment provided with the system and the ability of the system to meet specified effluent requirements shall be based upon:
- Minimum water temperature of sixty-eight degrees (68°) F.
- Maximum water temperature of ninety eight degrees (98°) F.
- Maximum ambient air temperature of one hundred twenty two degrees (122°) F.
- Maximum altitude of one thousand (1,000) feet.
- pH between 6.5 and 8.5.
- Sufficient nitrogen, phosphorous and other nutrients for biological stability.
- Sufficient alkalinity to stabilize pH.
- An absence of industrial waste or other toxic chemicals in the wastewater.
- If galley waste is to be processed, the galley drain(s) shall be equipped with a properly sized and maintained grease trap.
- Installation and operation of the system in accordance with the manufacturer’s instructions.
If beneficial nitrification is required, then in addition to the above requirements:
- pH between 7.0 and 8.5.
- The presence of indigenous nitrifying microorganisms.
- Sufficient alkalinity to permit the specified degree of nitrification.
- The nitrogen to be processed must be biodegradable and capable of being hydrolyzed to ammonia.
- The wastewater to be processed will be essentially free of quaternary ammonia and other compounds known to inhibit beneficial nitrification.
Unless otherwise specified, corrosion protection and electrical enclosures will be based upon below-deck installation. Water piping and fittings will be PVC or CPVC schedule 80 or PVC hose with PVC combination nipples.
External air piping and fittings will be schedule 40 galvanized steel. Current standard valves are 316SS. But, valves may also be bronze or PVC depending upon the service and associated piping.
Steel Tanks and Skids
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 interior joints shall be full welded both sides all around. For offshore installations exposed to the weather, all other exterior welds shall also be full welded.
For below-deck installations which are protected from the weather, other external seams may be welded three (3) inches on twelve (12) inches both sides all around. But, structural joints shall be full welded.
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:
- Steel surfaces shall be grit blasted to SSPC-SP-5 white metal with a profile of 1½ (1.5) to three (3.0) mils.
- For below-deck installations, all steel surfaces shall be protected with a polyamine epoxy resin coating (6 8 mils DFT total). Machinery will be installed with the original manufacturer’s standard coating.
- For above-deck and other installations exposed to sunlight and salt spray, exterior surfaces shall be protected with organic zinc primer (2-4 mils DFT), polyamine epoxy resin (6-8 mils DFT total) and 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
As applicable, 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.
As is the case with steel tanks, polyethylene tanks and associated skids shall be designed to withstand maximum storm sea conditions specified by US Coast Guard in 33CFR159.
Units shall comprise two or more modular components, media tank and machinery module. Each polyethylene tank shall be secured to a 304SS steel skid which can be welded or bolted to steel structure.
Unless otherwise specified, electrical equipment shall meet US Coast Guard electrical engineering regulations 46 CFR Part 111 and ABS requirements for below deck installations.
Motors for below-deck installation shall be TEFC or submersible as applicable and suitable for 50° C. ambient air temperature. In some cases, motor nameplates will specify service factors of 1.15 or 1.25 at 40° C. ambient air temperature, also suitable for operation at 50° C. ambient with service factor of 1.0.
For above-deck and offshore installations exposed to the weather, blower motors shall be TEFC, suitable for 50º C. ambient air temperature and shall be meet either IEEE-841 severe duty or IEEE-45 commercial marine requirements.
In some cases, close-coupled motors for exterior duty will have IEEE-841 features but may not be able to attain the efficiency specified in IEEE-841 due to dimensional considerations. In such cases, the nameplates will not indicate IEEE-841.
Motor starters shall have NEMA 4/4X or IP 55 enclosures as applicable.
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 in commercial marine or offshore service.
The Media Tank shall be hydrostatically tested per 33 CFR Part 159. No leaks are permitted.
With the Blower(s) operating, the proper operation of Airlifts and Air Scours shall be confirmed and as applicable, water shall be introduced into the Wet Well to check operation of the Float Switch and Discharge Pump(s) or Effluent Pump as applicable.
Carbon Steel Piping
Carbon steel piping shall be per ASTM A-53 Grade B minimum. Associated customer connections shall be one hundred fifty (150) PSI raised face flanges per ASTM A-105.
Three (3) inch and larger piping shall be welded and flanged. Weld fittings shall be per ASTM A-234B, and all flanges shall be per ASTM A-105. Smaller piping may be threaded.
Threaded fittings shall be per ASTM A-197 and shall be one hundred fifty (150) PSI minimum. Threaded piping for air or freshwater may be galvanized and not painted.
Stainless Steel Piping
When specified, stainless steel piping shall be per ASTM A-312, ASTM A-376 and MIL-P-1144. In general 316SS will be used for exposure to seawater and salt spray. 304SS may be used for freshwater and for applications protected from exposure to seawater.
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.
For all FAST units other than LX-Series, valves shall be rated for one hundred fifty (150) PSI service and as specified below:
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.
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.
Check valves shall be Sharpe 20276 threaded or equal, horizontal swing, screwed cap, integral seats. Cover, pin nut, disc and body shall be 316SS.
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.
LX-Series FAST units shall employ PVC ball valves GEORG FISCHER Type 353 or equal, per ASTM D‑2467.
PVC hose shall be GEN-LINE PRODUCTS Heavy Duty Suction & Discharge Hose Series 600 or equal, with gray PVC tube and cover, white helix reinforcement. The main application is the gravity Spillover from the Media Tank to the Tablet Chlorinator and from the Tablet Chlorinator to the Wet Well.
Depending upon the nature of the pipe run, the combination nipples may be PVC, nylon or 316SS. Hose clamps shall be 316SS with 316SS worm.
Air and water suction hose shall be Gates Barracuda or equal, with EPDM tube, synthetic textile reinforcement and wire helix. The main application is airlift and air scour piping. It may also be used for water piping. Combination nipples shall be 316SS with 316SS hose clamps and 316SS worm.
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.
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 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.
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 – a division of Bio-Microbics, Inc.
12977 Maurer Ind’l Dr. | Sunset Hills, MO 63127-1515
Tel: (314)756-9300 | Fax: (314)756-9306