Average Discharge per flush = 5 gallons Average blackwater flow (toilets) = 700 gals/day Average graywater flow = 2377 – 700 = 1677 gals/day

What is an overboard discharge ? An overboard discharge (OBD) is the discharge of wastewater from residential, commercial, and publicly owned facilities to Maine's streams, rivers lakes, and the ocean

OBD limits for discharges greater than 2000 gpd

OBD Limits for discharges less than 2000 gpd Monthly Average Daily Maximum of: BOD 5 :30 mg/L Total Suspended Solids (TSS): 30 mg/L Settleable Solids: 0.1 ml/L Fecal coliform Bacteria: 15col/100ml pH not be less than 6.0 or greater than 8.5 Continued:

Chapter 241 MAINE SUBSURFACE WASTE WATER DISPOSAL RULES 144A CMR page document which describes design procedures and requiremenents. Includes dicsussion of wetlands (Posted on 113 website File name CMR 241)

Soil conditions and geology are major factors in subsurface treatment schemes.

The geology of the islands (Isle of Shoals) consists mostly of granite, metamorphic rock and diabase dikes. The soil is composed of decaying organic matter and fine products of weathering and glacial till has been found in some depressions on Appledore Island

Chlorination or ultraviolet units must be used as a means of disinfection. A minimum detention time of 20 minutes in an approved contact chamber. The total chlorine residual in the effluent must at no time cause any demonstrable harm to aquatic life in the receiving water. The total chlorine residual of the effluent may not exceed 1.0 mg/L at any time.

SECTION DESIGN REQUIREMENTS All systems: In designing any system, the site evaluator and/or professional engineer shall take into consideration lot size and configuration, slope, surface drainage, soil characteristics, the presence and depth of limiting horizons within the soil, soil permeability, type of wastes, and the projected design flow.

Influent BOD 5 = 441 mg/L TSS = 242 mg/L Wastewater (Grey + Blackwater) Characteristics:

Major blackwater source: 22 – 5 gallon flush toilets (sea water used for flushing)

The perc rate (measured in units of minutes per inch.) is calculated and averaged as the rate of all six (6) perc holes in the proposed absorption area. Hole no.Perc rate (min/in) Perc rate = 217/6 = 36.3 min/in (avg).

Percolation rate (min./in.) Treatment Area ft 2 /gal/day > 0.1Too coarse – < 60 See mounds

Sand Mound