Midpoint of quarter!
So far we’ve covered: •wastewater constituents and effects •basic sanitation •policy •soils •site evaluation •basic septic tank treatment •gravity drainfields and alternatives •nutrient removal and media filters
2nd half of quarter •conveyance systems for clustered systems •advanced treatment options •greywater treatment •roundtable with industry and guest speakers
GROUP PROJECTS ASSIGNED MAY 9th We’ve done away with homework 7 to allow more time for group project!! Ecological Engineering onsite and decentralized water is treated and recycled back to environment close to source of generation ecological engineering entire waste stream is treated and recycled back to environment close to source of generation, employs an ecological systems approach to treatment
“performance based” and ecological in both cases the engineer must understand workings of nature to evaluate impacts and predict fate of constituents wetlands engineers applying natural purifying abilities of wetland systems emulate and enhance for human benefit (possibly for wildlife/nature benefit)
combination of modern industrial world and natural world development of ecological engineering stems from many sources, aquaculture in Asia centuries old technology for treating wastewater and recycling nutrients, Ma, H.T. Odum, treatment wetlands, restoration ecology
ecological engineering Æ the design of ecosystems
Theoretical Ecology Environmental Engineering
Applied Ecology form groups of 2-4 people sitting near you take a few minutes to identify what you as a group agree is a key concept in ecological engineering and an example of what that means Key concepts from Ecological Engineering for Wastewater Treatment, Ed. Etnier and Guterstan, 1997
SELF-DESIGNING ECOSYSTEMS •humans select communities of species to mimic natural environment, maximize desired performance •successful design creates self-managed, self-sustaining system •in natural systems there is no “waste” – essential to recover beneficial properties
SUSTAINABLE ECOSYSTEMS •ecosystems are mainly fueled by photosynthesis •components replace themselves as they wear out •initial design and build might require fossil fuels, but after that should be self-sustaining
ECOSYSTEM CONSERVATION •wetland engineering has led to better understanding of human benefits of wetlands (e.g. flood control, water quality) and so contributed to their preservation
SYSTEMS APPROACH •working with an entire system, not individual species •consider system compartment by compartment to build it into a whole for modeling and systems engineering approach wastewater treatment environmental engineering large, centralized facilities are resource and energy intensive solutions to pollution problems ecological engineering minimize environmental stress (e.g. effluent discharge with nutrients to water bodies)
system can never fully incorporate ecological environment because by defining a system it will always have flow in and out of energy and materials
“performance based” onsite and decentralized has a lot in common with ecological hopefully environmental engineers can be more ecologically aware without changing their names Highschool in Denmark, totally closed loop system
NH Æ NO - plants using available nutrients 3 3
separate solids
purification by water plants 4 levels of carp fish d te ra ae
all food waste from kitchen
From Saxgren 1997 in Ecological Engineering for Wastewater Treatment, Ed. Etnier and Guterstan, 1997 flowforms mimic natural water flows to aerate water recirculate asymmetrically in figure 8 pattern
photos take from http://www.flowformsamerica.com/ Ashfield Massachusetts
Not your average wastewater treatment plant
Marsh constructed in true jungle fashion, with banana trees, flowers, a parrot, turtles, fountains and a daily monsoon complete with sound effects
1996 first municipal Solar-Aquatic® Wastewater Treatment Plant in the US
information and pictures from http://www.mwpca.org/ashfield.htm design flow 165 households/25,000 gpd achieves advanced tertiary treatment 10,500 square feet of greenhouse space
Process flow: 1. bar screen 2. ~1 day in preliminary conditioning tank 3. sodium bicarbonate to supplement low alkalinity 4. 48 1,000 gallon, transparent-walled, solar tanks with plants, snails, fish, microorganisms and bubblers 5. clarifier 6. sand filter 7. wetland for denitrification, 5000 ft2 of 4½’ deep crushed stone, methanol for C source 8. UV disinfection 9. flow is measured 10. through a dosing chamber goes to leaching field Bear River 1995-2004 Nova Scotia design flow 15,000 gpd/100 households avoided cost of conveyance by having treatment right in town 2,000 tourists per year altered in 2004 (???)
Benefits to the solar aquatic system: •< ½ sludge •aesthetics •educational •high level of treatment Disadvantages to the solar aquatic system: •more expensive than wetland •more complex than wetland Humboldt State University Wastewater Aquaculture Project in Arcata CA
•only facility in the world that raises salmonids successfully in reclaimed wastewater
•steelhead, cutthroat (chinook, coho, and sturgeon)
•mixed 50:50 with saltwater from the bay
•secondary effluent fertilizes zooplankton and invertebrates
•aquaculture effluent has less nutrients than secondary effluent
•nutrients are recycled biologically
http://www.humboldt.edu/~fish/programs/wastewaterhistory.html Penn State Center for Sustainability
•College of Engineering's Science, Technology, and Society program
•$150,000 grant from the Pennsylvania Department of Environmental Protection's "Growing Greener" Program for a Living Machine
http://www.rps.psu.edu/0009/machine.html http://www.engr.psu.edu/newsevents/EPS/v17n2_2001spring/back.htm Cluster greywater recycling system, composting toilets, urine diverting toilet
dip and trickle wheel, settling, vertical swamp, UV disinfection
From Thomas and Zeisel in Ecological Engineering for Wastewater Treatment, Ed. Etnier and Guterstan, 1997 temperature of a granite wall can be as high as 50°C greater than ambient temperature same wall covered 50% by vines will be ambient to 20°C cooler cooling a result of shade and evaporation evaporative cooling = air conditioning
From Kinsinger et al in Ecological Engineering for Wastewater Treatment, Ed. Etnier and Guterstan, 1997 Reference: Ecological Engineering for Wastewater Treatment, edited by C. Etnier and B. Guterstam, 1997, CRC Press