rainwater workshop notes
TRANSCRIPT
water
All Water
97% oceans
3% freshwater
Freshwater
Ice caps & glaciers 79%
groundwater 20%
Surface freshwater 1%
Easily Accessible Surface Freshwater
lakes 52%soil
moisture 38%
Rivers 1%
Water within
living organisms 1% atmospheric vapor 8%
The Big Picture
transportation32%
householdoperations35%
globalwarming
(greenhousegases)
householdoperations
32%
transportation28%
common
householdoperations
20%
transportation51%
toxic
airpollution
householdoperations
21%
food38%
common
food22%
transportation23%
toxic
waterpollution
food73%
water
food45%
land
habitatalteration
Air pollution
common toxic
food• 60% of USA land area used for crops
or to graze livestock• Food purchases by priority:• Meat and poultry• Fruit, vegetables and grains• Dairy products• Other (including seafood, alcohol, soft
drinks, specialty foods and tobacco)
• 800 million acres or 40% of land area used for grazing livestock, most of which used for household consumption
• (beef most serious, chicken and then pigs)
• 30% of total water consumed used for irrigation of fruits, vegetables and grains
• 5 out of 7 environmental impacts of food production find the majority of damage done through cultivation rather than packaging, processing, transportation and retail stages.
1,000 gallons of water Used to irrigate the grain
To feed the cow
8 lbs of grain to produce
1 lb beef
Water use
• The average household of four people in this country uses about 243 gallons of water per day.
• The average water use per person (including non-home water use) is over 100 gallons per day.
Water conservation
• Conventional– Washer 42 gal– Shower 5-10 gpm– Hose 5 gal/min– Irrigation 80,000 gal/yr
• Conserve– Front loader 7gal– Shower 2.5 gal/m– Trickle irrigation– Xeriascaping
Home water indoor and outdoor use
DAILY WATER CONSUMPTION AMOUNTS ACTIVITY
AVERAGE HOUSEHOLD HOUSEHOLD USING CONSERVATION METHODS Bath 36 gallons 15 gallons Brushing Teeth Tap Running = 2 gallons 1/2 gallon Dishwasher 15 gallons Short Cycle = 7 gallons Hand Washing Tap Running = 2 gallons 1/2 gallon Shaving Tap Running = 20 gallons Using Bowl = 1 gallon Shower (5 min.) Tap Running = 25-35 gallons Wet, Soap, Rinse = 5 gallons Toilet Flush 5-7 gallons Low Flush Toilet = 2 gallons Washing Car Tap Running = 180 gallons Stopping Tap = 40-50 gallons Washing Dishes by Hand Tap Running = 20-30 gallons Wash, Rinse in sink = 5 gallons Washing Machine Top Loading = 40 gallons Front Loading = 25 gallons Watering Lawn Tap Running = 10 gal/min Stopping Tap = 10 gal/min
Home indoor water use
dishes3%
toilet28%
leaks5% laundry
22%faucets12%
bathing30%
home indoor water use
Recycling water
• more than half the water you consume in your house per day can be recycled and reused
• This is called greywater
blackwater
• This is toilet water• To reduce use
– Dual flow .8/1.6 option– Use 5 gal bucket in shower to collect pre-heat
losses and use to flush toilet– Compost toilet reduces all water requirements
for toilet, living machines treat black/greywater with plants instead of chemicals
Rainwater collection
• 5 components:– 1. Collection area (roof or other)– 2. Transport to storage (gutters, etc)– 3. Filtering device– 4. Storage (tank or cistern)– 5. System to distribute
Filtration
• Charcoal and UV• For bacteria charcoal filters work best
– 2 steps - 20 micron then 5 micron– Can use cleanable and reusable filtersFor viruses only UV light can kill fluorescent tubes without coating work for
residential UV requirements
Storage
• Common are concrete or fiberglass• Above or below ground
Storage capacity
• Types– Concrete– Polyethylene– Ferrocement– Wood– metal
treatments• 1. Screening
• Strainers & leaf screeners
• 2. Settling• (sedimentation)
• 3. Filtering• Inline cartridge• Activated charcoal• Reverse osmosis• Slow sand
• 4. Disinfecting• Boiling• Chemical• UV• ozonation
Testing
• If using for drinking you must have the water microbiologically tested, for harmful forms of bacteria annually by the local health dept.
Diagram for landscape use• .43 psi per foot of water
elev• So a tank 10 ft tall has less
than 5psi• Drip irrigation needs at
least 15psi• So you need to pressurize
(pump, pressure tank and fine mesh filter)
• City of Austin customers receive $500 rebate for landscape rainwater systems
Calculating catchment area
• Length x width (roof)• Losses
– Metal .9– Asphalt .85– Cedar .80– Concrete .75
RWP (rainwater potential)
• Roof (sf) x rainfall (ft.) = cubic feet of rain• Cf x 7.4 gal/cf = gallons of water
Other options:Collection area (gravel w/ liner)Same equation as above
example
• NW bungalow• 25 x 40 sf = 1000sf of
roof area• 1000 x 3’ rainfall for
portland oregon annually = 3000cf
• 3000 x 7.4 gal/cf =• 22,200 gallons
• Asphalt roof 22,200 x .85 = 18,870 gallons
• Storage 3000 cf/20 feet (length = 150ft/15 (width) = 10 ft/height
• 4 people x 40 gal = 160 gal/day
• Design for dry season 3 months (90 days) = 14,400 gallons
Rainwater design in portland
Composting toilets
• Relieve over 20% of your water requirements saving up to 15 gallons of water per day from chemical treatment plants which end up in the river
Living machines & ocean arks
• MERTS• Marine and
Environmental Research Training Station
• Clatsop community college
• Astoria, oregon
MERTS
Ocean arks - aquaculture
vermiculture
• http://equaris.com/default.asp?Page=Separation
What is a natural wastewater treatment system?
• Diversity of biological processes• Self management and self-organized• Robust• Attached growth on biological and artificial media• Plants integral to natural treatment systems• Commonly designed to remove: BOD, NH3, NO3, TP, TSS, FC• Sludge digestion can be designed for removal every 10 or 20 years• Low energy, sludge & chemicals + easy operations = low life cycle cost
BoyneRiverEcologyCenter
