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In the second compartment of the septic tank, an Orenco Universal Biotube Pump Vault is to be installed. Within the screened pump vault is a duplex pump system. The pumps will alternate operations and will be set to timed dosing through the Orenco MVP Duplex Panel. Top float= High Level Alarm, with lag pump enabled. No. 2 float over-ride timer on. Bottom float=Timer on and off. Timer starts with off time count down. Off time is 60 min; on time is 38 seconds. Over-ride timer off time is 30 min and on time is 38 seconds. Screened effluent is pressurized through a 1.25" line into a 1.25" manifold. Five, V dia. laterals "T" connect to this manifold. Each lateral is 20 ft long, with a 1.0 ft long, 90' turn-up electrical sweeps at each distal end of the laterals with ball valves. These ends of the sweeps will be situated in valve boxes for easy access and will allow each lateral to be cleaned. Each lateral is to have 1/8" orifices spaced every 2.5 ft, for a total of 35. Each orifice will have orifice shields placed over them to prevent obstruction by drain rock. Residual head of last orifice is to be 5 ft. As illustrated on the attached aerial photo (§7.1.1, §7.1.4), the effluent is to discharge to a 22 ft E-W x 22 ft N-S =484 sf filter bed. EHD required filter bed area= 160 LFLL x 3 =480 s£ The 100% reserve area is also noted adjacent to the south of the primary filter bed. The floor of the filter bed must be set at 21" below existing grade. This will maintain the required 8' separation distance between the soil-effluent interface and the highest anticipated depth to groundwater: 12" drain rock under laterals + 1" drain rock for ht. of laterals + 2" drain rock above laterals+ 6" native excavated soil cover over filter bed (§9.4) =21". 120" (10 ft) =highest anticipated depth to groundwater minus 21" = 99" (8.25' separation distance). Filter fabric is to be laid over the drain rock before 6" native soil cover backfill to surrounding grade. The Attachments to this Report include the following Technical Data Sheets (T.D.S.): 1. Aerial Photo illustrating Modular Home footprint and 100% Replacement Filter Bed (§7.1.1). 2. MVP-DAX DM Setting Instructions for time dosing. 3. Splice Box 4. Float Switch Assemblies T.D.S. 5. PF Series 4" Submersible Effluent Duplex Pump System T.D.S. 6. High Head H= V (W/ Check Valve) 7. Universal Biotube Pump Vault T.D.S. CONCLUSIONS AND RECOMMENDATIONS The shallow subsurface soils underlying the subject property where the new filter bed disposal area is to be installed, reveals a silty sand soil structure with medium permeability at the 39" depth. Sufficient area exists for the 100% replacement area, as detailed on the aerial photo. The Operations and Maintenance Plan(§1.12.1) for this system includes periodic cleaning of the screened area of the Biotube, bottle brush cleaning of the discharge piping, and opening lateral distal valves to discharge biological growth. Page -2- Chesney Consulting