Diminished Wastewater Treatment: Evaluation of Septic System - PowerPoint PPT Presentation

Diminished Wastewater Treatment: Evaluation of Septic System Performance Under a Climate Change Scenario Jennifer Cooper Laboratory or Soil Ecology and Microbiology, University of Rhode Island

Acknowledgements and Funding Funding:  RI Agricultural Experiment Station  USDA Hatch Multi-state Project NE-1045  URI Sea Grant  URI Enhancement of Graduate Research Awards  URI Undergraduate Research Awards Research Team: Undergraduate Helpers:  Jose Amador – NRS  Juliana DeLuca  Tom Boving – GEO  Ethan Sneesby  George Loomis – NRS & NEOWTC  Joshua Sargent  Dave Kalen – NRS & NEOWTC  Ian Rambo  Ivan Morales – Ph.D. student  Rachel Naylor  Faith Anderson

How We Treat Human Waste Wastewater Treatment Plants Septic Systems  75% U.S. population  25% U.S. population  Monitored  Not monitored

Distribution of OWTS in the United States U.S. - 25% RI – 31% 10-25% 25-40% > 40%

The Problems BOD: Nutrients-N&P: Microorganisms: • • • Low O 2 /Anoxia Eutrophication Bacteria • • Fresh – P Viruses • Coastal – N • Protozoan O 2 O 2 • Anoxia O 2 • Worms O 2 O 2

OWTS Drainfield Treatment Microorganisms: BOD: Nutrients: • Predation • Microbial • Phosphorus • Fe/Al • Adsorption/ degradation hydroxides filtration • Adsorption/ precipitation • Nitrogen • Nitrification • Denitrification

Climate Change - Northeast Intergovernmental Panel on Climate Change (2013 report): 100 year predictions (Northeast) –  Sea levels rise 3-5 ft.  Increased precipitation  Elevated Source : Consortium for Climate Risk in the Urban Northeast temperature 2-5°C

Chronic Effects of Climate Change <1’ OWTS function under elevated sea level / groundwater conditions Source: NEOWTC @ URI

Physical Effects of Rising Temperature 14 13 12 11 [O 2 ] (mg/L) 10 9 8 7 6 5 4 3 2 1 0 5 10 15 20 25 30 T ( o C)

Biological Effects of Rising Temperature Davidson et al. (1998)

The Experiment: How Will Climate Change Impact OWTS?

Conventional System 1. Primary Treatment 2. Drainfield WATER TABLE 4. Controls - timers Advanced System 3. Shallow Drainfield 2. Secondary treatment 1. Primary treatment

Intact Soil Mesocosms

Present Climate vs. Climate Change Conventional Advanced 77 cm 77 cm 46 cm Water Table Water Table Water Table 25°C 20°C

RESULTS

Oxygen Conventional Advanced P&S - present climate SND P&S GEO 0 0 0 P&S - climate change -15 -15 -15 -30 -30 -30 Depth (cm) Depth (cm) -45 -45 -45 -60 -60 -60 -75 -75 -75 -90 -90 -90 Present climate -105 -105 -105 Climate change -120 -120 -120 18.5 19.0 19.5 20.0 20.5 18.5 19.0 19.5 20.0 20.5 18.5 19.0 19.5 20.0 20.5 O 2 (%) O 2 (%) O 2 (%) Hotter, wetter soil – less oxygen, more reducing conditions

Biochemical Oxygen Demand (BOD) Conventional Advanced 3.0 3.0 3.0 GEO P&S SND 2.5 2.5 2.5 2.0 2.0 2.0 BOD 5 (mg/L) BOD 5 (mg/L) BOD 5 (mg/L) 1.5 1.5 1.5 1.0 1.0 1.0 0.5 0.5 0.5 0.0 0.0 0.0 Present Climate Climate Change Present Climate Climate Change 1 2 1 2 Present Climate Climate Change 1 2 Increased temperature likely speeds microbial C degradation

Fecal Coliform Bacteria Conventional Advanced P&S SND GEO 6 6 6 FC (CFU/100mL) FC (CFU/100mL) FC (CFU/100mL) 4 4 4 2 2 2 0 0 0 1 2 1 2 1 2 Present Climate Climate Change Present Climate Climate Change Present Climate Climate Change Increased moisture likely diminished microbial attachment

MS2 Bacteriophage - Virus Conventional Advanced  No virus in output water  Present climate and climate change conditions  For all drainfield types  pH more important than wetter/hotter conditions  Virus will have (+) charge at drainfield pH (~3.2)  Aids in retention to ( – ) charged soil particles

Total Nitrogen Conventional Advanced 60 60 60 SND P&S GEO 40 40 40 TN removal (%) 20 20 20 TN removal (%) TN removal (%) 0 0 0 -20 -20 -20 -40 -40 -40 -60 -60 -60 1 2 1 2 1 2 Present Climate Climate Change Present Climate Climate Change Present Climate Climate Change Conv.: Increased moisture, more anoxia, more hetero. denit. Adv.: Temperature increased C degradation, limited hetero. denit.

Total Phosphorus Conventional Advanced P&S GEO SND 100 100 100 TP removal (%) TP removal (%) TP removal (%) 80 80 80 60 60 60 40 40 40 20 20 20 1 2 Present Climate Climate Change 1 2 Present Climate Climate Change 1 2 Present Climate Climate Change Increased moisture likely caused reduction/dissolution of metals allowed P mobilization

Phosphorus Conventional Advanced 1.2 1.2 1.2 SND P&S GEO Proportion of P in output water 1.0 1.0 1.0 Non-metal Non-metal Non-metal Mn 0.8 0.8 0.8 Mn Mn 0.6 0.6 0.6 Al Al Al 0.4 0.4 0.4 Al Al 0.2 0.2 0.2 Al Fe Fe Fe Fe Fe Fe 0.0 0.0 0.0 SND PC SND CC P&S PC P&S CC GEO PC GEO CC Climate change: P in output water due to metals becomes more important than non-metal mechanisms (e.g. P-accumulating organism)

Mass Balance Units: kg/yr (FC in CFU/yr)

Mass Balance - Conventional Present Climate Climate Change BOD 5 : 0.180 BOD 5 : 0.05 FC: 1.6 x 10 8 FC: 0.0 TN: 6.32 TN: 6.50 TP: 0.241 TP: 0.489 kg/yr (FC in CFU/yr) in output water

Mass Balance - Conventional Present Climate Climate Change BOD 5 : 0.180 BOD 5 : 0.05 FC: 1.6 x 10 8 FC: 0.0 TN: 6.32 TN: 6.50 TP: 0.241 TP: 0.489 kg/yr (FC in CFU/yr) in output water

Mass Balance - Conventional Present Climate Climate Change BOD 5 : 0.180 BOD 5 : 0.05 FC: 1.6 x 10 8 FC: 0.0 TN: 6.32 TN: 6.50 TP: 0.241 TP: 0.489 kg/yr (FC in CFU/yr) in output water

Mass Balance - Conventional Present Climate Climate Change BOD 5 : 0.180 BOD 5 : 0.05 FC: 1.6 x 10 8 FC: 0.0 TN: 6.32 TN: 6.50 TP: 0.241 TP: 0.489 kg/yr (FC in CFU/yr) in output water

Mass Balance - Advanced Present Climate Climate Change BOD 5 : 0.10-0.13 BOD 5 : 0.0-0.03 FC: 1.9-2.2 x 10 8 FC: 0.0 TN: 6.13-6.26 TN: 6.73-7.04 TP: 0.0-0.011 TP: 0.241-0.259 kg/yr (FC in CFU/yr) in output water

Mass Balance - Advanced Present Climate Climate Change BOD 5 : 0.10-0.13 BOD 5 : 0.0-0.03 FC: 1.9-2.2 x 10 8 FC: 0.0 TN: 6.13-6.26 TN: 6.73-7.04 TP: 0.0-0.011 TP: 0.241-0.259 kg/yr (FC in CFU/yr) in output water

Mass Balance - Advanced Present Climate Climate Change BOD 5 : 0.10-0.13 BOD 5 : 0.0-0.03 FC: 1.9-2.2 x 10 8 FC: 0.0 TN: 6.13-6.26 TN: 6.73-7.04 TP: 0.0-0.011 TP: 0.241-0.259 kg/yr (FC in CFU/yr) in output water

Mass Balance - Advanced Present Climate Climate Change BOD 5 : 0.10-0.13 BOD 5 : 0.0-0.03 FC: 1.9-2.2 x 10 8 FC: 0.0 TN: 6.13-6.26 TN: 6.73-7.04 TP: 0.0-0.011 TP: 0.241-0.259 kg/yr (FC in CFU/yr) in output water

Increasing Coastal Population 39% of US population reside in coastal shoreline counties

Summary Effects of Climate Change Positive Effect Negative   Fecal coliform BOD bacteria  Total N*  Total N*  Total P