For over 30 years, Ek Engineering has helped guide Southwest Washington property owners through the permitting process so they can install new or repair existing septic systems.

TYPICAL SEPTIC DESIGN PROCESS:

1.) Data Collection: We begin by searching through permits & records to find what information is available for the property. This includes reviewing neighboring surveys, soil maps, & aerial photos. The gathering of data prior to meeting our client on site ensures that our designers are informed about your property’s history and unique soil characteristics.

2.) Dig Test Holes: Next, we arrange for a backhoe to meet with us on site for test hole excavation & soil evaluation. At this time, we do field exploration to find the most suitable and cost-efficient site for the new or repair septic drain field. The best test holes are left open for evaluation.

3.) Evaluation: The soils and sites of the most suitable test holes are evaluated, allowing us to develop preliminary recommendations that we then submit to the county. This recommendation typically includes a conceptual design proposal for the health department to do a cursory review of when they visit the site.

4.) Application: We prepare all applications and soil evaluations to be submitted to the county. If necessary, we meet county representatives at the site when they go to verify the soils. Once we receive approval from the county, our customer is quickly notified.

5.) Design: Our professionals prepare a design that is to be submitted to the county. The county reviews the design, and we make any changes they may require. This site-specific design is rendered with the intent of being most cost-effective while meeting the rigorous requirements of the code.

6.) Installation Inspection: After the permit is issued, the system can be installed by an approved, certified installer.  Once installation is complete, the licensed designer performs a thorough inspection of the site and installation.  This inspection ensures that the installer installs per design, so the property owner is receiving what they pay for.  This inspection also ensures that the installation meets all local codes, which protects the public health and environment.

7.) As-Built: For all septic designs in most counties, the designer is required to record an As Built record drawing, which entails drawing up on computer-aided design (CAD) all the components, with critical distances to known points referenced for future locates.  Also, the designer, together with the installer, fills out a Onsite System Checklist, which details materials used, model numbers, pump rates, timer settings, etc. for future maintenance reference.  Final approval is sent to the county so they can authorize the final occupancy of the home.

PRIMARY TYPES OF SYSTEMS:

Standard / Conventional: (greater than 4 feet good soil)
This is the good old-fashioned septic system, with the septic tank settling out the solids & providing anaerobic treatment. The clarified liquids flow out by gravity to a distribution box that evenly distributes the effluent to each drain field line. Most drain fields currently are constructed with "gravel-less chambers." These are open-bottom, plastic chambers, which allow the lateral movement of the effluent across the trench bottom. They are proven slightly more cost-efficient and seem to more effectively disperse the sewage across the bio-mat at the trench bottom. (cost range: $6000-$8000*) *typical installation cost range of a 3-4 bedroom residence.

Pressure Distribution: (greater than 3 feet good soil)
These systems are similar to standards with the exception of the method of distribution. A pump chamber pumps the effluent (typically twice a day) to the drain field, which has small diameter PVC lateral pipes within it. These laterals have 3/16" orifices (holes) approximately every 6 feet. When the pump comes on, each orifice squirts an equal amount of sewage to its portion of the drain field.  (cost range: $8500-$10500*)

ALTERNATIVE TYPES OF SYSTEMS:  (less than 3 feet of good soil)

NuWater Aerobic Treatment Unit (ATU):
The NuWater ATU is an advanced treatment system that utilizes a treatment process to provide an excellent alternative to the traditional sand-based systems.  The treatment process begins when wastewater from the home flows into the tank’s pre-treatment, or trash compartment. It is here where micro-organisms begin to break down and convert the waste into gases and microbes. The waste then flows to the aeration chamber. Here, aerobic microbes digest the rest of the waste, leaving behind water with a low concentration of Suspended Solids, BOD, and pathogenic bacteria. After an average of 24 hours, the remaining fluid enters the clarifier where the waste, microbes and treated water are separated. The proprietary airlift returns the treated water to the pre-treatment compartment to be re-processed, further treating any remaining bacteria, nitrates, microbes or other wastes.  After this treatment process, the effluent enters a pump chamber for final dosing to the pressurized disposal component.  (cost range: $12000-$14000*)

Sand Filter:
Sand Filter Pretreatment systems are comprised of three key components: Septic Tank, Pump Tank, and Sand Filter.  Sewage enters the septic tank for anaerobic treatment.  After sufficient retention time for settling and decomposition of waste, the effluent flows to the pump chamber for metered dosing to the sand filter.  Sand filters are essentially a PVC lined box under the ground. Effluent is pumped into the top gravel layer (9 inches thick) for dispersal over the sand layer. The sand layer (24 inches thick) provides a place to live and work for the bacteria that consume the bad parts of sewage. By the time the sewage makes its way through all the sand, over 90% of the sewage strength is reduced. Then the cleaned effluent enters a pump basin for dosing to the final disposal component.  (cost range: $14000-$17000*)

Drip Irrigation:
These systems are very shallow systems for sites with very little available treatment soil and/or sites with challenging topography.  Drip irrigation consists of small diameter drip irrigation tube trenched or plowed into the ground approximately 6 inches deep.  Loops of the tubing typically run 18 inches or 24 inches on center, and have a supply manifold and a return/flush manifold pipe at either end of the loops.  Typically this type of system is preceded by an ATU and a pump chamber.  Inside the pump chamber is a “headworks”, which controls the flows from the effluent pump while filtering the flow.  The effluent pump typically operates 12 times per day, sending a constant pressurized flow to the tubing.  In the typical “continuous flush” systems, excess pressure and water flow operates as a flushing / scouring mechanism to keep the drip tubes clear.  While the pump is running, each emitter doses approximately ½ gallon per hour to it’s designated 2-3 square feet of dispersal area.  These types of systems are popular where space is a concern, as drip irrigation systems take very little space.  (cost range: $13000-$15000*)

Sand Mound / Glendon:
These systems are above-ground systems for sites with very little available treatment soil. The primary treatment is with sand media. With mounds, the treatment is propelled by gravity (see sand filter) through the sand, and goes directly from there to the soil. With Glendons, the treatment is by capillary action (upward flow) within a treatment basin, and then it flows over the sides through the sand into the soil. While necessary on wetter sites, both of these types are less popular due to their poor aesthetic qualities.  (cost range: $15000-$19000*)