Transcript Biosolids Overview Short School Training

Wastewater Reuse
Oregon State University
GEO 300
November 3, 2004
Russell Harding
Department of Environmental Quality
Water Quality Division
(503) 229-5284
[email protected]
What is Treated Wastewater?
Wastewater from a municipal
sewage treatment plant that has
been treated (e.g. biologically or
physically) to a level that allows its
use for beneficial purposes (e.g.
irrigation, manufacturing,
construction purposes)
What is in Treated Wastewater?
water
nutrients (low to moderate)
pathogens
organics (biodegradable & refractory)
dissolved inorganics (Na, Ca, Mg, B)
metals
residual chlorine
Reclaimed Water Sources
35,000 million gal/day wastewater (Solley et al. 1993)
– 925 million gal/day are reclaimed (or 3 percent)
» 650 million gal/day are irrigated
Industrial sources generate the highest volume of
reclaimed water
Food processors generate most reclaimed water from
industrial sources
Trend likely of increasing municipal sources, based on
TMDL and temperature issues
Reclaimed Water Applied/Year in Oregon
1996 Figures
• Municipal
2727 million gal.
• Industrial
4836 million gal.
• Total
7563 million gal.
Oregon Reclaimed Water
Other
Industries
5%
Municipal
36%
Food
Processors
59%
Why Land Apply Reclaimed Water?
WQ limited streams may be adversely
impacted by treated wastewater discharges
Need the water for agriculture, pastures,
plantation forestry, turf farms, golf courses,
municipal projects:
– Irrigation water may be seasonally limited
– No other water available for a planned use
Can improve crop yield and soil productivity
Reclaimed Water Regulations
OAR Chapter 340 Division 55 (1991)
Beneficial use policy
WQ Permit - NPDES or WPCF
Reuse management plan
Oregon Water Reuse Policy
It is the policy of the Environmental
Quality Commission to encourage the
use of reclaimed waters for beneficial
purposes using methods that assure
that the health of Oregonians and the
environment of the state are protected.
(OAR 340-055-0007)
Why Reuse?
Of all the water on earth:
three percent is fresh water;
two percent is locked up as ice;
one percent of the world's water available for drinking. But that one
percent is in trouble from:
impacts from demand versus supply (e.g. dessert communities)
pollution (e.g. historical discharges
lack of conservation (e.g. green, green lawns, pools, leaky pipes)
Land Application
• WPCF/NPDES permit required.
• Except for water authorized by permit, reuse plan
required.
• Health Services to approve plan.
• DEQ may consider blending.
• Water used on property not belonging to
treatment plant requires legally enforceable
contract.
• No human consumption without EQC approval
Groundwater Protection
No water reuse authorized unless all
requirements
of groundwater protection established in
Division 40 are met.
Land application at rates that will not allow
contaminants to leach to groundwater.
Water Reuse Plan
Reclaimed water use plan will
demonstrate how a treatment plant
operator will comply with these rules.
Reuse Management Plan Contents
• Facility Description (sources, flows)
• Treatment Process (disinfection)
• Effluent Characteristics (in detail)
• Storage (wintertime) and delivery system
• Contingencies (spills, upsets, start-up)
• Reporting (records)
• Intended Use Program (selecting sites)
Reuse Management Plan Contents
SITE
•
•
•
•
•
•
soils
topography
climate and micro-climate
site limiting factors
surface and groundwater
abutters
SITE RESTRICTIONS
Reclaimed water Levels 1-3 require:
• Site access restrictions and time
delays prior to crop harvest
• Posted signs
• Buffers around perimeter
• Control of aerosol drift
Reuse Management Plan Contents
APPLICATION RATE
• Key concept for agricultural
irrigation
• Water balance
• Nutrient needs
• Salinity
IRRIGATION SYSTEM
• Irrigation system Plans & Specs
(including pumping capacity &
head ratings)
• Cropping system
Other Requirements
No bypassing of untreated water.
Alarm devices and backup generators.
Sufficient excess capacity to prevent
discharge.
Annual report required.
Consumers required to read and
understand rules.
No water right conferred.
Treatment Requirements
Level I Level II Level III Level IV
Biological
Treatment
Disinfection
X
X
X
X
X
X
X
Clarification
X
Coagulation
X
Filtration
X
Total Coliform
Level 1
(organisms/100 ml)
Level II Level III
Level IV
2 Consecutive
Samples
N/L
240
N/L
N/L
7-Day Median
N/L
23
2.2
2.2
Maximum
Sampling
Frequency
N/L
N/L
23
23
N/R
1/week
3/week
1/day
Turbidity (NTU)
Level I
Level II
Level III Level IV
24-Hour Mean N/L
N/L
N/L
2
5% of Time in N/L
24-hours
Sampling
Frequency
N/L
N/L
5
Hourly
Public Access And Buffers
Level I
Public
Access
Level II
Level III
Prevented Controlled Controlled
Buffers Surface:
10 ft
Spray:
Site
Specific
Surface:
10 ft
Spray: 70
ft
10 feet
Level IV
No Contact
during
irrigation
None
Allowable Uses
Level I
Agricultural
Urban
Irrigation
Commercial/
Industrial
Construction
Impoundment
Level II
Level III
Level IV
Few
Most
Most
All
No
Some
Some
Yes
No
Yes
Yes
Yes
No
Yes
Yes
Yes
No
Some
Most
Yes
Wastewater Reuse
Considerations
•Costs
•Land use issues
•In-Stream flow