>95% of raw sewage is water, most of pollutants can be removed with a septic tank

1. Primary Waste Water Treatment with Septic Tank • >95% of raw sewage is water, most of pollutants can be removed with a septic tank • Heavier fractions sink to the bottom and are decomposed by bacterial interaction > SLUDGE • Lighter fractions such as oil, plastics, surfactants are trapped between baffles > SCUM • Scum & Sludge need to be evacuated periodically to sustain the septic tank effectiveness • Rainwater should not be fed to into septic tanks since it can flush scum and sludge into • the drainage gutters and out fall systems Tank sealing: Sikadur http://www.sika.com.ph/sikadur__31_cf_normal.pdf

2. Working hypothesis: DENR standards for deep sea discharge can be met, especially when the drainage system handles rainwater, septic tank effluents and sea water infiltration together, allowing for sufficient dilution prior to release to the ocean. Bounds, T.R., “ Design and Performance of Septic Tanks,” “Current septic tank technologies are capable of treating wastewater (onsite) to a higher level of quality than do the vast majority of municipal treatment plants. Properly designed, these onsite technologies are more fail safe and fail soft than municipal facilities. Effluent sewer and onsite wastewater technologies have been established as an affordable and reliable alternative. Passive—energy free—septic tanks provide the most cost efficient method of primary treatment available for nonindustrial sewage.” Tautology: “In theory any effluent could be diluted with sea water until it would meet DENR standards before being discharged to the ocean” http://www.csuchico.edu/cwtrc/PDFFILES/Updates/Boundsseptictank.pdf

3. CONCEPT DEEP SEA OUT FALL deair SEPTIC TANK desinfect Collection Tank +10m ASL rain water Pump-out Surge tank beach shore line costal water = <3 km or <200m BSL

4. CT Sabang Small LaLaguna Big LaLaguna st st st st st st st beach st beach beach st = surge tank with sump pump ct = collection tank deep sea out fall

5. = new installation rain gutter beach-front path Septic tank surge tank & sump pump gutter, sewerage beach shorefront effluent HDPE collection pipe buried in beach HDPE pipe jointed by butt welding and thermoplastic coupling for pressure rating of min 3 bar (30m head)

6. Sump pump operation during brown out utilizing existing private backup generators (instead of deploying a dedicated backup power system) grid power Private resort/hotel with backup generator charges Barangay for sump pump power consumption ATS meter GENSET soft starter sump pump - 1KW resort/hotel

7. Max. 3500 m3/day = 40 liter/sec = 150,000 liter / hr (PEMSEA assumption -- for validation) Collection tank for de-airation and desinfection: 20 m3 Collection Tank (approx 15m above high tide level) 1m Sump pump with 15 m head and 40 liter/ sec capacity has a power requirement of approx. 16 * 15 * 40 = 9,6 KW . Distributed to 10 surge tanks along the beaches that’d be 10 sump pumps with 1 KW rating each on average. The genset backup thus should have a rating of at least 15 KW, provided the sump pumps are fitted with soft starters. Pumps will only operate in unison during heavy rain, otherwise intermittently whenever the surge tank fill level so requires. Out Fall with .55 m/s flow to convey +40 liters/sec would need a diameter of 1 ft. Depending on length of out fall, head and suction a out fall point, a lesser diameter of 1 ft may be viable. Head to over come pipe pressure drop (@ 2km length) = ~ 2,3 m Head to overcome density delta 1.026 * depth of 100m = ~ 2,6 m http://www.pressure-drop.com/ 2 m 10m sump pump (generic)

8. Securing out fall pipe to the sea bead Options: - bury in the near foreshore - weigh down with stones - “nail” down with augers - utilize wreck material - attract coral growth new coral growth nylon tie stone auger

9. Diffuser Concept with Suction Effect Note: ocean water has higher density than waste water. The delta determines how high the feed-in point has to be above sea level for the waste water to flow through the out fall pipe by gravity alone. The deeper the discharge point below sea level the higher the feed-in point above sea level. If waste water contains bubbles the water column in the out fall may “float”, thus flow would stop. Essential then to allow waste water to de-air in the collection tank. suction and diffusion cone prevailing currents flexible hose waste water out fall anchored on ocean bed • waste water extraction by ocean current • reduces head • - regulates outflow according to current • contains initial mixing zone in cone • avoids siltation of outlet vents • reduces risk of out fall flotation Flow resistance of pipe (smooth bore or spiral) adds to required head to achieve flow requirements.

10. “Septic tank performance can be maintained by periodically evacuating accumulated scum & sludge” Cost of sewage evacuation truck: “under 1 mio Pesos”

11. Bill of Materials –preliminary estimate