comparing nitrogen removal of various onsite treatment systems

recode Effluent Plumes from 4 Different Onsite SystemsComparing Nitrogen Removal

Oregon, Residential Strength Wastewater

Sweden: High Risk Areas 2006, NSF/ANSI 245: Nitrogen Reducing Systems 2007, Oregon: Alternative Technology Treatment Standard 22007, Deschutes County: Existing Development 2008, Maryland: Chesapeake Bay Critical Areas 2012

While implementation varies from setting adischarge concentration of 30mg/L (Maryland), tosetting a % reduction standard (Deschutes,NSF/ANSI), to setting total yearly discharge capand % reduction standard equivalent to 30mg/L(Sweden), this is the most common discharge limit.Finland 2004

Washington: Treatment Category 1, Level A 2007Deschutes County: Future Development 2008

Recent concerns over nitrates in groundwater and surface waters have driven tighter regulations on nitrogen discharge. All the standards listed below have been implement-ed since 2004. Performance standards in Finland and Sweden allow interventsions at the toilet or after the septic tank. Prescriptive codes in the US limit systems to nitrogen reduction after the septic stage.

18%

Dry Toilet with Septic for

Washwater

100%

20%

Septic with Urine Diversion

Septic System E�uent

16%

Septic with Sand Filter & Wood Chip

Filter

$7,000

$1,200-6,000$25,000

retrofit: $3,000 to 6,000

available at www.recodeoregon.org/resourcesinfographic by Molly Danielsson

property boundaries

recode Effluent Plumes from 4 Different Onsite SystemsCitations

USEPA 2002: “Onsite Treatment Systems Manual” EPA/625/R-00/008Pie Charts, sources of nutrients Figure 3-7Infiltration based on 10-40% removal N, 85-95% removal of P, 90-98% removal BOD5, Figure 3-17Septic Effluent, Figure 3-19

Septic Tank with Dry Composting Toilet82.1% of total Nitrogen is from toilet: USEPA 2002. 17.9% x 24 to 90 = 4.3 to 16.11 mg/L N

Septic Tank with Sand and Wood Chip Filter10 mg/L of N: Oakley, Stewart, Arthur Gold, Autumn J Oczkowski. Nitrogen control through decentralized wastewater treatment: Process perfomance and alternativemanagement strategies. Ecological Engineering. 36(11):1520-1531. November 2010. p 1

Septic Tank with Urine Diversion“80% of N and 50% of P from domestic wastewater at treatment plants is contained in urine.” Larsen, T.A., Gujer, W., 1996. Separate management of anthropogenic nutrientsolutions (human urine). Water Science and Technology 34 (3–4), 87–94.

Sand Filter and Wood Chip Filter based on Nitrex TM System. Lombardo, Pio. Phone Interview. May 2, 2012.

Dry Toilet based off of VeraMiljoe’s Carousel dry toilet. www.vera.no

Urine Diversion retrofit based off Swedish prices as of 2006 excluding 25% tax. Avloppsguiden.se