Water Treatment
Environmental Science
Sunday, March 3, 2013
Water Sources
Water Vapor
Soil
Water
Well
Surface Water
Ground Water in Aquifer (porous rock)
Impermeable Rock
Sunday, March 3, 2013
Uses
Agricultural (69%) - Irrigation, Livestock
Industrial (21%) - Power Plants, Manufacturing
(ingredient, cooling, cleaning), Mining, Fracking,
Shipping
Domestic (10%) - Drinking, Flushing, Hygiene,
Cleaning
Sunday, March 3, 2013
Water Pollution
Any change in water quality
that adversely affects the
health of humans and other
living organisms.
Sunday, March 3, 2013
Code Blue Activity
Pollutants
Sources
P vs NP
NP
• chem. fertilizers • Farming
• mercury
• Coal burning
NP
P
• oil
• Oil wells
P
• abandoned nets • Fishing
P
• antibiotics
• Aquaculture
• litter
• Ships, Other P, NP
P
• sewage
• Homes
• debris
• Natural Disasters NP
Sunday, March 3, 2013
Other Water Pollutants
Pollutants
Sources
Disease-Causing
Organisms
•
Sediment
•
Thermal
Pollution
•
Sunday, March 3, 2013
Sewage - Human
and Animal
Farms, Mining,
Construction
Industry, Tree
clearing
Water Treatment
water
source
Water Treatment
Plants
Sunday, March 3, 2013
stream
Wastewater (Sewage)
Treatment Plants
Home,
Industry,
Farm
Drinking Water Treatment
Aeration
Alum g Flocculation
groundwater
Settling Tanks
Text
Cl2 to kill
pathogens
Filter-Sand/Gravel/Charcoal
Sunday, March 3, 2013
Safe Drinking Water Act
• Enacted in 1974
• Monitors municipal drinking water
facilities
• Set national standards for maximum
contaminant levels - levels above which
are considered unsafe for human
consumption.
Sunday, March 3, 2013
Examples of National Primary
Drinking Water Standards
Sunday, March 3, 2013
Rio Grande Water
• Gallia Rural Water
• Wells along Route 7
Sunday, March 3, 2013
Source, Use and Cost?
• 500-3000 gallons/person
• $15 - $100/month
Sunday, March 3, 2013
Water Treatment
water
source
Water Treatment
Plants
Sunday, March 3, 2013
stream
Wastewater (Sewage)
Treatment Plants
Home,
Industry,
Farm
Clean Water Act
• Enacted 1972
• Goal is to return surface waters to “fishable
and swimmable”
• Funded sewage treatment
• Regulates Industry
Sunday, March 3, 2013
Sewage
Wastewater from drains and sewers.
Contains human feces, dirt, soap, etc.
Needs O2 to be decomposed
Many animals cannot live in low O2
Sunday, March 3, 2013
Wastewater Treatment
• See Textbook Figure 10.2
Primary Treatment
Secondary Treatment
Screen
Aeration
Sedimentation
Sludge
Sunday, March 3, 2013
Sedimentation
Primary Treatment
• Removes larger particles
• Screens remove large particles
• Settling tank allows sediment to
Screen
Sedimentation
settle and oil to float to top.
• Clean water is taken from in
between.
• Settled sediment is termed
sludge
Sunday, March 3, 2013
Sludge
Secondary Treatment
• Removes oxygen-demanding waste (detritus)
• Decomposers feed on sewage, aeration speeds up
decomposition.
• Sediment is allowed to settle out as sludge and
water is taken from top.
• Water is disinfected with chlorine before release.
• Some sludge is reused, rest is removed and dried for
disposal.
Sunday, March 3, 2013
Sewage Treatment Summary
Removed
Text
• sediments
• detritus
• disease
organisms
Sunday, March 3, 2013
What isn’t removed?
• non-biodegradable
soaps
• metals
• other?
Tertiary Treatment
• Most facilities do not do additional treatment.
• Some plants have special processes to remove
specific items - metals, nitrates, phosphates - not
removed by primary or secondary treatment.
• Expensive
Sunday, March 3, 2013
Wetlands
• Some facililties release water into wetlands
which can filter out nutrients and metals.
• Orlando Florida (textbook figure 10.22)
• Oregon Gardens (personal photo)
Sunday, March 3, 2013
Septic Tanks
• Septic tanks are mini-sewage plants for individual
homes.
• Cement tank receives waste
• Aerator motor provides aeration
• Drains to creek or drainage field
• Needs to be pumped out every few years
Se
Sunday, March 3, 2013
Source Reduction
• Produce less waste at source instead of
cleaning up later
• See Textbook figure 10.15 and Table
10.3
• Water pollution reduction methods for
home
• Grey water
Sunday, March 3, 2013
Control from Industry
• The Clean Water Act requires industries to apply
BPCT - best practicable control technology
• May be their own sewage treatment facility.
• Includes holding ponds to cool hot water before
release.
• Industries must have permits to release a
pollutants, fined if they exceed amount.
• Some industries will pay fine rather than install
technology to reduce pollution.
Sunday, March 3, 2013
Farms
• Bare Soil - Sediment
• Fertilizers - Plant Nutrients-->Algae
Blooms
• Pesticides - Toxins
• Manure - Sewage and Disease Agents
Sunday, March 3, 2013
Agriculture Controls
Reduce Soil Loss and run-off of sediments, manure,
fertilizers and pesticides into streams
Filter Strips
Contour Plowing
Crop Residue
No-Till Plowing
Sunday, March 3, 2013
Filter Strips
Strips of grass between field and waterway.
Sunday, March 3, 2013
Contour Plowing
Plowing along the curves of the land.
Sunday, March 3, 2013
Crop Residue
Leave behind crop residue over winter.
Natural nutrient cycling.
Sunday, March 3, 2013
No-Till Farming
Growing crops without tillage (digging soil)
Sunday, March 3, 2013