Wastewater Reuse Oregon State University GEO 300 November 3, 2004 Russell Harding Department of Environmental Quality Water Quality Division (503)

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.

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 )

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 ILevel IILevel IIILevel IV Biological Treatment XXXX DisinfectionXXX ClarificationX CoagulationX FiltrationX

Total Coliform (organisms/100 ml) Level 1Level IILevel IIILevel IV 2 Consecutive Samples N/L240N/L 7-Day Median N/L232.2 Maximum N/L 23 Sampling Frequency N/R1/week3/week1/day

Turbidity (NTU) Level ILevel IILevel IIILevel IV 24-Hour MeanN/L 2 5% of Time in 24-hours N/L 5 Sampling Frequency Hourly

Public Access And Buffers Level ILevel IILevel IIILevel IV Public Access PreventedControlled No Contact during irrigation BuffersSurface: 10 ft Spray: Site Specific Surface: 10 ft Spray: 70 ft 10 feetNone

Allowable Uses Level ILevel IILevel IIILevel IV Agricultural FewMost All Urban Irrigation NoSome Yes Commercial/ Industrial NoYes Construction NoYes Impoundment NoSomeMostYes

Wastewater Reuse Considerations Costs Land use issues In-Stream flow