The right water. The right use. Brenley McKenna April 5, 2016 - - PowerPoint PPT Presentation

The right water. The right use.

Brenley McKenna April 5, 2016

Presentation Objectives

• Current Regulation 84
• Proposed Changes
• Approach
• Address Total Dissolved Solids and Salinity
• Drivers for Increased Reuse

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Regulation 84

“It is the intent of the Commission that this regulation further promote reuse of reclaimed domestic wastewater by providing a comprehensive framework which, when followed, will assure responsible management of operations and a product of a quality compatible with the state's goals of protecting the public health and the environment...” 84.21 B

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Current Regulatory Framework

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Level of Treatment Uses Restrictions Category 1 Category 2 Category 3 Few Many Many Few

Proposed Changes

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Level of Treatment Uses Restrictions Category 1 Category 2 Category 3 Category 4 Category 5 Few Many Many Few

Proposed Changes to Regulation 84

• New Categories and Uses:

– Category 3

• Livestock wash-down

– Category 4

• Commercial agriculture for edible crops
• Toilet flushing

– Category 5

• Edible crops in urban gardens

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Proposed Changes

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Level of Treatment Uses Restrictions Category 1 Category 2 Category 3 Category 4 Category 5 Few Many Many Few

Approach

• White Paper for Edible Crops
• Model changes after other states regulations

– Goal:

• Protection of human health and the environment
• Minimize Risk
• Increase utilization of recycled water

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Variations in Water Quality Requirements

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Most Stringent Least Stringent CA ID TX OR WA AZ

• Disinfection (CT values, residual, log removal)
• Total Coliform/ E. coli
• Turbidity
• Monitoring
• Redundancy
• Treatment

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Idaho: Reclaimed Water Quality

Operational Considerations

• Access
• Training
• Cross connection test
• Backflow requirements
• Signage
• Dual plumbing

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Considerations for Changes to Regulation 84

• Change of Definitions

– Reclaimed Water – Restricted Access/ Unrestricted Access – Toilet/ Urinal Flushing – Trained Worker – Commercial Agriculture – Agricultural Irrigation – Agricultural Irrigation User

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TDS AND SALINITY

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Agronomic Principles

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• Plant physiology: plant life depends on water
• All water contains some salt
• Salts include nutrients essential for plant growth and health
• Sodium is not an essential nutrient
• Chloride is essential at extremely low concentrations, as is

boron

• Too much of anything (including salts) can be toxic to plants
• Environmental stressors can complicate the picture

Water Quality Parameters and Landscape Health

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Source: Average 2015 Irrigation Season Water Quality

Tempe, AZ Drinking Water Quality Constituent Range Average Salinity (EC) (dS/m) .693-2.170 1.194 Sodium (mg/l) 50-350 152 Boron (mg/l) 0.13-.6 0.15 Chloride (mg/l) 60-420 215

Source:2014 Tempe Water Quality Report

None Slight to Moderate Severe

Salinity – EC (dS/m) Sodium – Na (mg/L) Boron – B (mg/L) Chloride – Cl (mg/L) Management and Restrictions

0.7 3.0 70 0.7 100 3.0

0.995 110 0.28 162

Water Quality Parameters and Landscape Health

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Source: Average 2015 Irrigation Season Water Quality

Tempe, AZ Drinking Water Quality Constituent Range Average Salinity (EC) (ds/m) .693-2.170 1.194 Sodium (mg/l) 50-350 152 Boron (mg/l) 0.13-.6 0.15 Chloride (mg/l) 60-420 215

Source:2014 Tempe Water Quality Report

None Slight to Moderate Severe

Salinity – EC (dS/m) Sodium – Na (mg/L) Boron – B (mg/L) Chloride – Cl (mg/L) Restrictions

0.7 3.0 70 0.7 100 3.0

0.995 110 0.28 162

Site Maintenance: Management vs. Treatment

• Similarities with Potable Water:

– Right Plant in the Right Place – Know Your Soil Characteristics – Know Your Water Quality and the Best Irrigation Method

• Differences from Potable:

– Monitor More Frequently – Test Soil Routinely – Leach/Amend Soil to Prevent Salt Accumulation – Reduce or Eliminate Fertilizer Salts

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DRIVERS FOR INCREASED REUSE

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Colorado’s Water Plan

• Guidance document specifically named reuse as an aid in

reducing the water supply gap.

• 8 Actions specific to increasing reuse in Colorado

– Increasing funding and incentives for water recycling and expanding the list of uses for which recycled water can be applied.

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One Water In Practice

• Uses the most appropriate source water for

each water use

• Avoids using potable water for non-potable

purposes

• Minimizes potable water demand through

conservation measures

• Minimizes discharges to the environment

through resources recovery and reuse

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Questions?

Contact Information

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Brenley McKenna Reusable Water Program Manager 303.628.6011 brenley.mckenna@denverwater.org Damian Higham Recycled Water Specialist 303.628.6537 damian.higham@denverwater.org

Back Up Slides

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Other Sources of Salinity

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• There are many other sources of salinity both natural and anthropogenic

that can impact landscape health:

• Agricultural practices
• Commercial and industrial activity
• Road/ sidewalk de-icing activities
• Water softeners
• Household cleaning products
• Inflow & Infiltration
• Ground water
• Treatment chemicals
• Fertilizer

Texas: Type 1 Reclaimed Water Quality

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Colorado: Category 3 Reclaimed Water

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Salinity and Sodicity Levels

Parameter Acceptable Level* Average DW 2015 Levels Salinity Less than 4 dS/m 0.98 dS/m Sodicity Less than 12-15 % 4.43%

* These levels will vary based on soil type and species tolerance levels. Management is still recommended for concentrations within the acceptable level.

On-Site Use; New Uses for Reclaimed Water

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Conventional Water Flow

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Normal water flow is linear and single-use. Potable water is discharged to sanitary sewer after use. Rainwater flows to storm sewer.