Water Treatment
Environmental Science
Water Sources
Water Vapor
Soil
Water
Well
Surface Water
Ground Water in Aquifer (porous rock)
Impermeable Rock
Uses
Agricultural (69%) - Irrigation, Livestock
Industrial (21%) - Power Plants, Manufacturing
(ingredient, cooling, cleaning), Mining, Fracking,
Shipping
Domestic (10%) - Drinking, Flushing, Hygiene,
Cleaning
Water Pollution
Any change in water quality
that adversely affects the
health of humans and other
living organisms.
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
Other Water Pollutants
Pollutants
Sources
Disease-Causing
Organisms
•
Sediment
•
Thermal
Pollution
•
Sewage - Human
and Animal
Farms, Mining,
Construction
Industry, Tree
clearing
Water Treatment
water
source
Water Treatment
Plants
stream
Wastewater (Sewage)
Treatment Plants
Home,
Industry,
Farm
Drinking Water Treatment Activity
Aeration
Alum g Flocculation
groundwater
Settling Tanks
Text
Cl2 to kill
pathogens
Filter-Sand/Gravel/Charcoal
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.
Examples of National Primary
Drinking Water Standards
Rio Grande Water
• Gallia Rural Water
• Wells along Route 7
Source, Use and Cost?
• Gallons per month?
• 500-3000 gallons/person
• Cost?
• $15 - $100/month
Water Treatment
water
source
Water Treatment
Plants
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
Sewage
Wastewater from drains and sewers.
Contains human feces, dirt, soap, etc.
Needs O2 to be decomposed
Many animals cannot live in low O2
Wastewater Treatment
• See Textbook Figure 10.2
Primary Treatment
Secondary Treatment
Screen
Aeration
Sedimentation
Sludge
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
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.
Sewage Treatment Summary
Removed
Text
• sediments
• detritus
• disease
organisms
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
Wetlands
• Some facililties release water into wetlands
which can filter out nutrients and metals.
• Orlando Florida (textbook figure 10.22)
• Oregon Gardens (personal photo)
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
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
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.
Water Pollution from Farms
• Bare Soil - Sediment
• Fertilizers - Plant Nutrients-->Algae
Blooms
• Pesticides - Toxins
• Manure - Sewage and Disease Agents
Agriculture Controls
Reduce Soil Loss and run-off of sediments, manure,
fertilizers and pesticides into streams
Filter Strips -Strips of grass between field and waterway.
Contour Plowing-Plowing along the curves of the land
Crop Residue-Leave behind crop residue over winter.
No-Till Plowing-Growing crops without tillage (digging
soil)