wastewater reuse oregon state university geo 300 november 3, 2004 russell harding department of...
Post on 05-Jan-2016
214 Views
Preview:
TRANSCRIPT
Wastewater Reuse Oregon State University
GEO 300November 3, 2004
Russell HardingDepartment of Environmental QualityWater Quality Division(503) 229-5284harding.russell@deq.state.or.us
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?
waternutrients (low to moderate) pathogensorganics (biodegradable &
refractory)dissolved inorganics (Na, Ca, Mg,
B)metalsresidual 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.
O r e g o n R e c l a i m e d W a t e r
O t h e r I n d u s t r i e s
5 %
M u n i c i p a l3 6 %
F o o d P r o c e s s o r s
5 9 %
Why Land Apply Reclaimed Water?
WQ limited streams may be adversely impacted by treated wastewater dischargesNeed 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 requirementsof 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 RESTRICTIONSReclaimed 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
X X X X
Disinfection X X X
Clarification X
Coagulation X
Filtration X
Total Coliform (organisms/100 ml)
Level 1 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 N/L N/L 23 23
Sampling Frequency
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 24-hours
N/L N/L N/L 5
Sampling Frequency
Hourly
Public Access And Buffers
Level I Level II Level III Level IV
Public Access
Prevented
Controlled
Controlled No Contact during irrigation
Buffers
Surface: 10 ftSpray: Site Specific
Surface: 10 ftSpray: 70 ft
10 feet None
Allowable Uses
Level I Level II Level III Level IV
Agricultural Few Most Most All
Urban Irrigation
No Some Some Yes
Commercial/Industrial
No Yes Yes Yes
Construction No Yes Yes Yes
Impoundment
No Some Most Yes
Wastewater Reuse
Considerations
•Costs
•Land use issues
•In-Stream flow
top related