HomeMy WebLinkAbout2) Intro to Septics and Food ProcessingSeptic Considerations
Residential Design &
Food Processing
By Carter Erickson
Septic System Basics
1)The septic tank - provide a settling chamber.
2)The drainfield - provides an oxygen rich
environment for dispersal.
Goal = Prevention
Reduce disease causing organisms and nutrients to acceptable levels before they reach
Ground water - over 60% of drinking water is groundwater
Surface water - shoreline, shellfish, recreation
Hazel Point on the Coyle Peninsula
▪Bedrooms NOT Bathrooms
▪Sizing is based on assumed uses:
▪2 people per bedroom X 45 gallons/person/day X 33% surge
capacity = 120 gallons/day/bedroom
▪Minimum Capacity Required
▪2 bedrooms X 120 g = 240 GPD
Residential Septic Sizing
(WAC246-272A-0230)
Drainfield Sizing
(WAC246-272A-0234)
▪Hydraulic Loading Rates
(perk rates)
▪Based on soil conditions including
texture, compaction, and septic
system type (conventional,
pressurized, ATU, mound, etc.)
▪Finer texture soil or more compact =
bigger drainfield.
▪Most limiting factor takes precedent.
Soils Determine System Type
(WAC246-272A-0230)
▪Vertical Separation
▪The amount of dry, useable soil below
the drainfield.
▪Less useable soil = more pretreatment
required (ATU, mound, sandfilter, etc.)
Evaluate the soils
Example Design Calculations
▪3 bedroom house
▪Type 4 soil (0.6 gallons/sqft)
▪30” of dry, useable soil = pressure
3 𝑎𝑎𝑎𝑙𝑙𝑙𝑙𝑙× 2 𝑙𝑎𝑙𝑙𝑙𝑎/𝑎𝑎𝑎𝑙𝑙𝑙𝑙× 45 𝑎𝑎𝑙𝑙𝑙𝑙𝑙/𝑙𝑎𝑙𝑙𝑙𝑙× 33% 𝑙𝑙𝑙𝑎𝑎 = 360 𝑎𝑙𝑎
360 𝑓𝑎𝑙𝑙𝑛𝑛𝑠
𝑑𝑎𝑦÷ 1 𝑠𝑞𝑓𝑠/𝑑𝑎𝑦
0.6 𝑓𝑎𝑙𝑙𝑛𝑛𝑠=600 𝑙𝑙𝑎𝑙
600 𝑙𝑙𝑎𝑙 ÷ 3𝑎𝑙 𝑤�ℎ𝑎𝑎 𝑙𝑙𝑎𝑙𝑎�=200′𝑙𝑎 𝑎𝑙𝑎�ℎ𝑙𝑎�ℎ𝑎𝑙𝑎
3D models of septic systems
Resource from Tacoma-Pierce county Health Department
https://www.tpchd.org/healthy-homes/septic-
systems/understand-your-septic-system
Cottage Foods/Kitchens
▪Regulated by WSDA (WAC 16-149)
▪https://agr.wa.gov/departments/food-
safety/food-safety/cottage-food
▪Still must follow local rules/codes
Cottage Foods/Kitchens +
Septic Systems
▪WSDA is supposed to coordinate with
public health.
▪Does the septic have capacity for the
increased use?
▪Is the wastewater being treated
properly?
▪WAC 246-272A-0230 may require
specialty septic components.
Risk of Premature
Failure
▪What you put down the drain makes a difference
▪Cleansers – bleach, antiseptic products disrupt your septic tank
▪Fats, oils, & greases (FOG)
▪Garbage disposal → too many solids
▪Use of system beyond capacity
▪Large discharges
More Resources
▪Septic Homeowner Classes
▪Fall and Spring Every Year
▪September 29th, 1 - 4pm @ Quilcene
Community Center
▪October 1st, 1 – 4pm @ Tri-Area Community
Center
▪https://jeffersoncountypublichealth.org/670/Septic-
In-Person-Class-Schedule
▪Daily Sanitarian Hours: 9 -10:30am
▪Public Health Office 615 Sheridan St. Port Townsend
▪Via phone (360)385-9444
Questions..?
jeffersoncountypublichealth.org