(Advanced Treatment Technology)
AdvanTex | Whitewater | EnviroGuard
At the June, 2006
PADL annual event - Bill
Zekan, Lincoln County environmental manager, reported on the newest wastewater
ATTs (Advanced Treatment Technology), that were approved as
of March 1, 2005. Zekan can be contacted at the Lincoln County Planning
Department at 541-265-4192 in Newport.
Note: The first two ATTs always have a septic tank in front of them for immediate BOD reduction - gets the solids out, and floating soaps, greases and oils out in the tank. A maintenance agreement with four reports in a 2-year period is required with ATTs, with a fee tied to the life of the system. Zekan has brochures and website addresses for ATTs.
The Department of Environmental Quality (DEQ) administers regulations governing sewage disposal contracts with Lincoln County to handle sewage disposal for the state. Zekan has had a contract with the state in Lincoln County for 28 years. In 1974, DEQ took the sewage disposal program over from the state health division. Up to that time there were standard septic tanks and drainfields. After some time there was pressure on the legislature to open up more lands in Oregon. In areas of high groundwater it was difficult to get a septic approval. Landowners put pressure on the legislature who then went to DEQ to open up the rules intelligently. An experimental assistance program was begun, and they started to borrow ideas from other states. In 1981, the conventional sandfilter was approved - the sandfilter was borrowed and modified from the intermittent sandfilter developed by the University of Wisconsin at Madison.
Sewage is measured by several terms:
TSS - total suspended solids,
BOD5 - biochemical (biological) oxygen demand that is a term for the strength of the sewage (some sewage is stronger than others and harder to treat e.g., as high grease and oil from a restaurant)
Sandfilters treat the sewage to a fairly high degree with an effluent BOD5 of less than 10 and total suspended solids nearly the same. Sandfilters are expensive. DEQ criteria for the placement of sandfilters take into account water tables.
Water tables are separated into two kinds:
1) permanent groundwater table - usually exists close to the lake
Sandfilters require a minimum separation of 24 inches (depending on soil type) from bottom of absorption trench to permanent groundwater table
2) temporary groundwater table - water exists in a small portion of the year, in response to rainfall, that is usually perched or held up on a layer that limits the effect of soil depth or to a restricted layer. Along the coast it is usually sandstone. Sandfilters require 12 inches minimum from bottom of absorption trench to groundwater table.
The sewage disposal industry has grown in the last 20 years and produced new technologies that do the same thing a sandfilter does in less space. A sandfilter is about 360 square feet. New ATTs are used in other states and countries; the industry put pressure on the legislature to approve ATTs in Oregon. DEQ was hesitant because many of them were designed so that when they stopped working, they passed untreated sewage into their absorption facility. If not maintained properly, they put out a bad-quality effluent and contaminated groundwater and public water.
1) The state requires a stringent review process. NSF approval is needed.
2) All ATTs may not have a direct bypass.
3) If the unit is not functioning properly, the whole thing must stop.
Septic tanks and drainfields can fail. The system is complaint driven - homeowner, neighbors, and DLWID. Sandfilters have a box spread out with gravel and medium sand that acts as a physical and biological filter. The sand is dosed with liquid; a thin film holds the matrix of particles, and between the particles of sand live microorganisms that treat sewage.
The government process is slow. The state has approved three types of ATT units as of March 1, 2005.
1. AdvanTex (AX20) by the Orenco Company, www.orenco.com/, from Sutherlin, Oregon - Terry Bounds. It uses a textile filter. The box is set up horizontally with hanging sheets of material instead of sand. Sewage is spread out over the surface area for the bacteria to digest the sewage. A valve allows the effluent out of the ATT into the drainfield; however, the sewage can be recycled through the system several times to get cleaner effluent. The sheets can be washed off or replaced. The AdvanTex size is about 4 by 7 feet.
Aerobic bacteria live in the top 2 to 3 feet of soil and oxidize sewage (organic matter) to carbon dioxide and water. The septic tank and drainfield work well if sited properly. Zekan tests soils, looking for soil profiles and signatures in the soil that tell where the water table comes from and where the water flows. A septic tank has anaerobic and aerobic bacteria. A watertight septic tank with enough retention time can get a BOD reduction of 50-70% in the tank alone. The solids drop out, and the soaps, greases and oils float to the top. The effluent flows out of the middle of the tank into the drainfield (soil absorption or treatment field). Soil and microorganisms produce a fairly well-treated effluent that reenters the hydrological cycle: Lake to ocean and back up to the atmosphere.
The sandfilter and the ATT replaced the job of the soil and are used where the soil is not good. Effluent not processed or sitting for over a month can cause problems.
Zekan said that Lincoln County has one of the top programs in the state and trains young people. Brooks Rodman, a soil scientist from Oregon State University, works with Zekan.
Zekan does not think that ATTs put out a better effluent than a sandfilter does. Sandfilters take up 360 square feet - 10 by 36 feet. The lake area has small lots. Onsite septic systems were not designed for small lots, but for large, rural areas. ATTs allow less footprint for the filter, but this does not change the requirements for the drainfield over a sandfilter system. The drainfield requirement is 45 lineal feet per bedroom in the house. For a 2 bedroom house the requirement is 90 lineal feet of drainfield. The drainfield for a regular septic system without a sandfilter or ATT - may require 100 feet of drainfield per bedroom (minimum is 2 bedroom or 200 feet of drainfield compared to 90 feet of drainfield for an ATT). The misconception is that more Lincoln County land can be opened up because of the new systems, but there are still drainfield requirements, including a reserved 90 feet of drainfield for repair if the initial system fails. A bedroom is not defined as a room with a closet. A bedroom for the last ten years is what it is called - bedroom (window issues), office, den, library, sewing and/or music room. To upgrade a home and add a bedroom - go to the county and apply for an authorization notice to have the system inspected. The county determines if any changes are needed and if there is a drainfield area to fix the septic system if it fails. The repair system could be designated as a sandfilter or an ATT (because takes less room), which means if the system fails, a sandfilter system will need to be purchased at $15,000 to $20,000. The ATT is about the same price but is easier to install.
Community wastewater systems are cumbersome legally. Landowners need to form an organization or municipality and collect money. Lincoln County does not have any that are done correctly – some done in the 1970s. If cross a property line, the county requires an easement. If the house on the community system is sold, a drainfield will be needed if not on sewer.
Bob McKnight asked if adding beer to a septic tank was helpful, but Zekan said no. Sweitz installs septic tanks. Bacteria need sewage in the presence of oxygen to multiply. The ATTs add more oxygen to speed up the process and require less space.
Jim McFarlane asked about sandfilters. 1) sandfilters do fail, 2) sandfilters last a long time but require maintenance, and they can fail from hydraulic overload - if a home is left vacant over a long period of time, the bacteria die off. If there is an increase of people using the system, there may not be enough bacteria left to take care of the effluent. With added use the system flushes through too quickly to treat the sewage. Bacteria work best if fed regularly. Sandfilters put out an effluent better than a 5 BOD. ATTs operate the same - best with regular doses of sewage. ATTs probably do not produce a better effluent than sandfilters.
2. Whitewater is an activated sludge type of treatment. It is a tank with an inner tank shaped like a cone. An aerator and outside compressor box shoots air into the side of the tank. Oxygen speeds up the decomposition process. In the cone the clear water rises to the top and the sludge stays at the bottom of the cone and is reintroduced for finer break down. Zekan likes the simplicity of this system. The size is between the AdvanTex and the Enviroguard. See www.canwest-tanks.com/whitewater.html
3. Enviroguard has one unit with 3 chambers. The first trash tank acts as a septic tank and does not have a preceding septic tank. Next there is a dosing tank, which goes to the real treatment tank with a combination of textile filter and activated sludge. Next there are air pumps with a circle of socks of textile (polyester fiber) hanging to act as a filter. The system is complicated.
The first two ATTs always have a septic tank in front of them for immediate BOD reduction, gets the solids out, and floating soaps, greases and oils - layer out in the tank.
The ATTs, instead of sandfilters, are not approved for use in areas of permanent groundwater table. They are for use in temporary water tables only. They intend to approve them for use in permanent groundwater table areas if tertiary treatment is added (maybe in a year). Tertiary treatment cleans sewage better with chlorine, UV light, ozone and other ways.
A maintenance agreement with four reports in a 2-year period is required with ATTs, with a fee tied to the life of the system. Zekan thinks this will become a huge industry. A sandfilter does not require a maintenance agreement. For maintenance, the sandfilters need pumping every three years with the lines jetted out. The ATTs have a lot of moving parts that can break - pumps, compressors, etc. AdvanTex will call the homeowner with a web-based telemetry system.
The county seeks solutions. Zekan says the county helps people with no resources and told about installing one system for a family with a handicapped son. County has a slide show about how they help citizens.
Pump your septic tank when needed. Don’t let the material from the sludge accumulate in the tank. It is bad to pump a tank when not necessary; Have the tank checked. Citizens can call Zekan, and he will schedule a time to check septic tanks. He has brochures and website addresses for ATTs.
Primary - in the tank
Secondary - in the filter or drainfield
Tertiary - chlorine, UV, ozone, etc.
What comes out of the ATT kills about 90% of viruses. If water is discharged into a lake, the goal is to kill off rest of the viruses.
Copyright © 2003-2011
Preservation Association of Devils Lake (PADL).
All rights reserved.
P.O. Box 36
Lincoln City, OR 97367