Store onboard in sealed bins/lockers. No overboard discharge of plastics/dunnage. Food waste macerated >3nm (or >12nm if not macerated).
Garbage Management Plan required for vessels ≥ 100 GT or certified for 15+ persons. Record keeping in Garbage Record Book.
Underway (Offshore)
Compact/incinerate (large ships). Store for port disposal (yachts). Food waste overboard >12nm (macerated) or >25nm (unmacerated).
Zero tolerance for plastics anywhere. E-waste, cooking oil, cargo residues have specific rules.
1.2 Grey Water (Showers, Sinks, Laundry, Galley)
Context
Standard Practice
Regulatory Framework
At Marina
Often discharged directly overboard (soap suds visible). Some marinas require holding tanks or shore-side pump-out connections (rare for grey water).
Generally unregulated internationally (MARPOL Annex IV covers sewage only). Local/State laws vary wildly (e.g., US Clean Water Act, EU directives, Alaska/California strict bans).
At Anchor / Underway
Direct overboard discharge via through-hulls or sump pumps.
Few restrictions beyond "no visible sheen/foam" in many jurisdictions. Moving toward stricter nutrient limits in sensitive areas.
1.3 Black Water / Human Waste (Sewage)
Context
Standard Practice
Regulatory Framework (MARPOL Annex IV / USCG 33 CFR 159)
At Marina
Mandatory Holding Tank. Y-valve locked to "Tank" position. Pump-out stations used weekly/bi-weekly.
Zero discharge in most inland/coastal waters (NDZ - No Discharge Zones).
At Anchor (Coastal)
Holding Tank only. No overboard discharge (often within 3nm limit).
Must hold until pump-out or >3nm offshore (with Type I/II MSD treatment).
Underway (Offshore >3nm / >12nm)
Type I/II MSD (Maceration + Chlorination/UV) discharge allowed >3nm. Untreated holding tank discharge allowed >12nm (varies by flag state).
International: Treated effluent >3nm, Untreated >12nm (if comminuted/disinfected). US: Stricter, often requires Type II/III (holding) in coastal zones.
Vacuum/Low-flow (50 gal tank, 0.75 gal/p/day): ~33 Days.
Reality Check: Most cruising couples pump out every 7–14 days. "Liveaboard" at anchor without pump-out access requires either massive tanks (100+ gal) or treatment/discharge capability.
2. Technology Evaluation for High-Power Seastead
Your design has triple-redundant LiFePO4 + Solar + Inverters. This changes the calculus entirely: Energy is cheap/abundant; Volume/Weight are the premium constraints (Containerization).
Urine diverted to separate tank (or grey water). Solids fall into chamber with coconut coir/peat moss. Agitator mixes. Aerobic bacteria dehydrate/compost. Vent fan (12V/24V DC, ~2-5W continuous) pulls air *out* through carbon filter/vent stack = Zero Odor.
Capacity/Endurance
Solids Bin: ~60-80 uses (3-4 weeks for couple). Urine Tank: ~3-5 days (10L) unless plumbed to grey/black system. No "Flush" Volume.
Venting: Requires 2-3" vent pipe through roof/wall. Must stay dry (rain caps). On a heaving seastead, vent stack height matters for draft.
Urine Disposal: Still need a plan for 2-4 Liters/day/person. Cannot just dump in grey water if regulations prohibit nutrient loading (e.g. Florida Keys, coral reefs).
Compost Maturity: Output is "pre-compost" (pathogens remain). Requires secondary composting (12+ months) before safe for food gardens. Legal disposal often = bagged trash.
Motion: Agitators handle heave well; urine diverters need careful aim in rough seas.
Containerization: Excellent. No through-hulls, no plumbing, no holding tank volume.
2.2 Electric Incinerator Toilet (e.g., Cinderella, Incinolet, EcoJohn)
Aspect
Details
How it Works
User places paper/bowl liner in bowl. Press button. Electric elements (1.5kW - 2.5kW) incinerate waste to sterile ash (1 tbsp per use). Cycle: 45-90 mins. Catalytic converter/afterburner handles smoke/smell. Vent pipe required (exhaust hot ~150-200°C).
Capacity/Endurance
Unlimited (limited only by ash bin emptying ~1 cup per 50-70 uses). Zero Liquid Waste. Handles urine + solids + TP + tampons.
Power Budget: 10 kWh/day is ~830 Ah @ 12V or ~210 Ah @ 48V. Your LiFePO4 bank (est. 50-100 kWh+) handles this easily, but it is a significant % of a typical yacht solar array. For your design: Trivial load.
Venting: Requires dedicated 3-4" insulated stainless vent through roof. High heat = fire risk if installation sloppy. Must penetrate your 7ft ceiling/roof structure.
Peak Load: 2kW surge. Your inverters (likely 3kW-5kW each leg) handle this, but don't run microwave + incinerator + water maker simultaneously on one leg inverter without load management.
Noise: Fan + burner noise audible in quiet cabin.
Containerization: Excellent. No plumbing, no tanks. Just ash box (hazardous waste? usually general trash).
2.3 Marine Wastewater Treatment System (Type II MSD / Advanced AWTS)
Aspect
Details
How it Works
Black + Grey water combined (or separate). Aerobic treatment (MBR - Membrane Bioreactor, or SBR - Sequencing Batch Reactor). Bacteria digest organics. UV/Chlorine/Chlorine Dioxide disinfection. Output: Clear, odorless, near-potable water (BOD/TSS < 10-30 mg/L, Fecal Coliform < 14/100ml).
Capacity/Endurance
Unlimited. Continuous flow. Tankage only for surge/equalization (50-100 gal).
Complexity: Highest. Requires trained operator or service contract. Not "fit and forget."
Volume/Weight: Heavy tanks, blowers, control panels. Eats container volume.
Regulatory: Type II Certificate allows discharge >3nm. In NDZ (No Discharge Zones) or sensitive areas (coral), you still need a holding tank to retain treated effluent.
Grey Water Integration: Best if Grey + Black combined (nutrients help bacteria). If separate, need carbon dosing for Black only.
Sludge: Produces biosolids (sludge) requiring pump-out every 3-12 months.
3. Recommendation: The "Incinerator + Grey Water Strategy" for Your Design
Verdict: Electric Incinerator Toilet is the OPTIMAL choice for THIS specific design.
Why? You have the "Holy Grail" of seasteading: Massive Electrical Surplus + Severe Volume/Weight Constraints (Container) + Regulatory Uncertainty (International waters/Flag State).
3.1 Why Incinerator Wins Here
Eliminates Black Water Plumbing: No 3" hoses, no Y-valves, no macerator pumps, no 100-gallon holding tank eating your 62,000 lb displacement / container volume.
Eliminates Through-Hulls Below Waterline: Critical for your "Leg" design. Drilling 3" holes in NACA 0035 foil legs for discharge is a structural/leak nightmare. Incinerator vents out the roof (atmospheric pressure, easy sealing).
Regulatory Immunity: Ash is inert solid waste (MARPOL Annex V - Garbage). No sewage discharge regulations (Annex IV) apply. Legal everywhere.
Power is "Free": Your legs hold ~25% displacement in LiFePO4 (~15,500 lbs ≈ 7,000 kg ≈ **250-350 kWh**). A 10 kWh/day load is 3-4% of total capacity. Solar (44ft triangle roof ≈ 1,450 sq ft ≈ 20-30 kW peak) recharges this in <1 hour of sun.
Containerization: Unit is self-contained box. Fits in "center of container" spare space easily.
3.2 Implementation Details for Incinerator on Seastead
Location: Mount in "wet head" compartment against outer wall (one of the 3 wall panels) for shortest vertical vent run through roof.
Venting: Double-wall stainless (Selkirk/Metalbestos) penetrating roof. Terminate above solar panel rack height + rain cap. Insulate well where passing through living space (7ft ceiling).
Power Management: Wire to "Leg 1" Inverter (dedicated 20A/240V or 40A/120V breaker). Add "Load Shed" logic: If Leg 1 Inverter > 80% load, delay incinerator cycle 15 mins (unit has buffer).
Redundancy: Carry 1x Portable Composting Toilet (e.g., box + bags + coir) as emergency backup if power/inverter fails.
4. Grey Water Strategy for Seastead
Since Incinerator eliminates Black Water, Grey Water becomes your only liquid waste stream.
4.1 The "Container/Seastead" Constraint
No large holding tanks (volume/weight).
Legs are structural foils; minimize through-hulls.
Walkway/Wall structure: 7ft high, 3ft walkway. Grey pipes can run inside wall cavity or under walkway grating.
Galley + Head Sink + Shower drain by gravity to central sump (low point in triangle center, under floor panels).
Primary Treatment
In-line Grease Trap / Filter (stainless basket) at galley sink. Hair/Lint catcher at shower. Bio-enzymatic dosing (automatic peristaltic pump) in sump to reduce odor/BOD.
Pump
Single 12/24V Centrifugal Pump (Rule/Whale) in sump -> Overboard discharge.
Discharge Point
Above Waterline. Through wall panel (above 3ft walkway level) or through leg fairing above max waterline. NO below-water through-hulls. Splash discharge = aeration = odor control.
Coastal/NDZ Mode
3-Way Valve diverts to 50-Gallon "Day Tank" (collapsible bladder or slim poly tank tucked under floor/berth). Capacity: ~2-3 days for couple. Pump out via deck fitting to marina pump-out truck or tender to shore.
Why not treat Grey Water to potable? Reverse Osmosis (Watermaker) makes fresh water from sea (energy ~3-4 kWh/100gal). Treating grey to potable (MBR+RO) costs 10x energy/complexity. Just make fresh water from sea. Discharge grey responsibly.
Black Water: Incinerator running normally. Ash bin emptied weekly into sealed bucket -> Garbage.
Grey Water: Direct overboard discharge via above-waterline outlet (Legal >3nm / >12nm depending on flag). Valve set to "Overboard".
Garbage: Compact (trash compactor or manual crush). Plastics/Metal/Glass stored in sealed bins on walkway/deck locker. Food waste: Macerate (insinkerator style) + discharge >12nm (MARPOL) OR dry/store for incinerator (if capacity allows) OR bag for port disposal. Recommendation: Small food waste macerator -> Grey water sump -> Overboard (legal offshore).
Documentation: Garbage Record Book (if flagged commercial/large) or Logbook entry (private).
5.2 Scenario B: Coastal Cruising / Anchored Near Shore (Non-NDZ)
Black Water: Incinerator normal.
Grey Water: Valve set to "Day Tank" (50 gal). Monitor level. When full (2-3 days), motor tender to pump-out facility or use macerator pump to discharge >3nm if legal for your flag.
Garbage: Store all. No overboard discharge (MARPOL).
5.3 Scenario C: No Discharge Zone (NDZ) / Marine Park / Coral Reef (e.g., US Keys, Bahamas Parks, EU MPAs)
Black Water: Incinerator normal (Zero discharge = Compliant).
Grey Water: **ZERO DISCHARGE REQUIRED.** Valve to Day Tank. Must pump out Grey water at facility.
Strategy: Limit stay to <2 days (Grey tank limit) or arrange pump-out boat service.
Garbage: Zero discharge.
6. Tension-Leg Mooring (Station Keeping) Waste Plan
Context: 3 Helical Screws deployed, Seastead tensioned down 3ft. Stationary for months (Caribbean, low tide range). Community of multiple seasteads connected.
6.1 Infrastructure Required (Shared/Communal)
System
Description
Communal Pump-Out Barge/Boat
One dedicated small workboat (electric) with 200-500 gal vacuum pump-out tank. Services all seasteads on a schedule (weekly).
Grey Water "Shore" Connection
Floating hose manifold connected to seastead deck fitting. Runs to communal Constructed Wetland / Reed Bed on a dedicated "Utility Float" or ashore if near land. Low tech, zero power, handles nutrients.
Garbage/Recycling Barge
Weekly collection. Compactor on barge. Backhaul to municipal dock.
Incinerator Ash
Collected in sealed buckets during pump-out run. Hazardous waste stream (heavy metals from pharma? usually classed as general waste but best practice: separate).
6.2 Per-Seastead Hardware for Mooring Mode
Deck Pump-Out Fitting: Standard 1.5" or 3" camlock on deck (port & stbd) connected to Grey Water Day Tank (and optional Black Water tank if you install one for redundancy).
Vent Filtration: Carbon filters on Grey Water tank vents (odor control for neighbors 20ft away on walkways).
Walkway Protocols: "No Discharge" policy while walkways connected. Valves locked to "Tank".
6.3 Community Waste Treatment Plant (Optional Upgrade)
If community > 10 seasteads permanent: Deploy a containerized **MBR Plant (20ft ISO container)** on a dedicated float. All seasteads pump Grey + Black (if any non-incinerator units) to it. Produces irrigation water for community hydroponics/reef restoration. Powered by community microgrid.