Limno lecture - lec 8 constructed wetlands

reasons for wastewater treatment facilities

• dwindling water supplies

• water shortages

• water reuse

water reuse

• alternative water source for irrigation

• water treatment (wastewater, backwash water, and runoff)

• riparian habitat for migratory birds

• new problems of _____: potential viruses, other endocrine disrupters

soil-aquifer treatment

the use of soil as a filter to reclaim stormwater or wastewater

Phytoremediation

the use of plants to enhance the degradation of pollutants in stormwater or wastewater

treatable pollutants

• waste water (human and animal)

• acid mine drainage (add alkalinity)

• leachate from landfills (San Joaquin Marsh does this)

• stormwater

• agricultural runoff (fertilizer, pesticides, feces. lots of ammonia)

surface flow (SF) wetlands

• type of constructed treatment wetlands

• water is passing over the soil

• plants are in emergent zone

• lower flow system. most effective during dry season

subsurface flow (SSF) wetland

• type of constructed treatment wetlands

• water drains through gravel substrate

• passes through pipe in order to be collected as treated water

• low flow system. most effective in dry season

vertical subsurface flow/percolation design

• type of constructed treatment wetlands

• combination of surface and subsurface

Columbia, Missouri

• homeplace of a water treatment facility

• handles 200 million gallons - coming in and going out

• handles many farms

• pumped out into irrigation systems

Fairfield City, Australia

• homeplace of a small water treatment spot

• probably just handles the community’s runoff

Clarksville Treatment Facility

• treatment wetland right next to dairy cows at University of Maryland

• specifically handles the waste from cows

• 1st step - filter. can collect manure to compost

• 2nd step - treatment lagoons. maybe some microbes digesting stuff

• 3rd step - storage tank

• 4th step - wetland cells. 75 gallons of water managed per cell per day

rain shadow

air from the coast rises over mountains and cools down. water precipitates and rains on the coast side of the mountain range. on the other side of the mountain, the air is dry as hell and its desert AF

Irvine Water Ranch District

• removes 70% of nitrogen from San Diego creek (75,000 lbs per year)

• processes 3.5 million gallons a day

• pathogen removal - sunlight at the surface

• nitrogen removal - mostly benthic bacteria

• phosphorus removal - sedimentation/plants. phosphorus is bigger so its just kinda getting stopped by clay and rocks

modeling constructed wetlands

We take ideas from natural wetlands:

• use the same ecological and biochemical functions

• high primary productivity - take up a lot of nitrate, phosphate, and Co2

• able to sequester carbon and certain pollutants like selenium

they do not:

• protect animals and habitats

• do compensatory mitigation

• do ecological restoration

stormwater treatment constructed wetlands

• swales - drainage ditch. vegetated or nonvegetated

• stormwater basins - slowly dissipate flood waters

• rain gardens

• roof gardens

• xeriscaping - using drought resistant plants. can be watered with wastewater, reclaimed water, and stormwater

oil and grit separators

Skims off motor oil

used next to parking lots

swales

bio_____ - creeks that are full of plants. thick soil

have a little depression, in order to pick up more water

dry_____ - some are dry and have gravel underneath

grass _____ - basically just drainages ditches

can be bioretention cells (filter systems) or not!

Low impact development

suburban areas that take up less space

smaller footprint

shared driveways with rain gardens between houses