The Water Reuse Roadmap

By Water Environment Federation

Increasingly, our demands for water for both human activity and the environment, are pushed to the limits of naturally available water resources. Engineered water reuse systems can harness natural cycles to augment water demands, but the challenges, opportunities, and benefits of water reuse are broad and diverse.

The Water Reuse Roadmap is an overview of all the opportunities and issues faced by water reuse projects. Developed to help water managers facilitate successful water reuse programs, from concept development through implementation and maintenance, the guidance in this book enables water managers to

1. determine the social, technical and financial feasibility of water reuse options in their specific situation,
2. initiate a water reuse program when appropriate, or
3. expand an existing reuse program based on new approaches and opportunities for innovation.

It begins with initial concept development; then describes stakeholder engagement, regulatory, risk assessment, and planning processes; and finishes with advice on financing, implementing, operating, and maintaining water reuse infrastructure. In addition to this detailed guidance, the Roadmap includes case studies to help water managers holistically identify, evaluate and implement their water reuse options.

• Language: English
• Publisher: Water Environment Federation
• Release date: Aug 1, 2017
• ISBN: 9781572783447

Book preview

1

Introduction

Vijay Sundaram, P.E., and James Crook, Ph.D., P.E.

1.0     WATER REUSE AND ITS DRIVERS

2.0     THE WATER REUSE OPPORTUNITY

3.0     DEFINITIONS

3.1     Uses and Delivery Methods

3.2     Water Reuse Options

3.3     Water Types and Quality

3.4     Treatment Technology

4.0     THE WATER REUSE SPECTRUM

4.1     Environmental Restoration—Tres Rios Wetland Restoration, Phoenix, Arizona

4.2     Agriculture Reuse—Monterey Salinas Valley Edible Crop Irrigation, Salinas Valley, California

4.3     Landscape Irrigation—St. Petersburg, Florida

4.4     Industrial Reuse—West Basin’s Designer Water, Los Angeles, California

4.5     Groundwater Recharge—El Paso, Texas

4.6     Seawater Intrusion Barrier and Indirect Potable Reuse—Orange County Water District Groundwater Replenishment System

4.7     Surface Water Augmentation—Upper Occoquan Service Authority, Virginia

4.8     Direct Potable Reuse

5.0     INTEGRATED RESOURCE MANAGEMENT AND WATER REUSE

6.0     THE WATER REUSE ROADMAP DEVELOPMENT AND ITS ORGANIZATION

6.1     Water Environment Federation, Water Environment & Reuse Foundation, National Water Research Institute, and WateReuse Association Experts’ Meeting

6.2     The Water Reuse Roadmap Primer Development

6.3     The Water Reuse Roadmap Organization

6.4     Planning

6.5     Implementation

6.6     Operation, Maintenance, and Monitoring

7.0     REFERENCES

1.0     WATER REUSE AND ITS DRIVERS

Water is essential to life, and it is becoming increasingly difficult to provide adequate water supplies to an ever-increasing human population. People are adversely affected by the lack of an adequate water supply. The most acute problems are inadequate water to drink and grow food crops, both of which are essential to life. Further effects include limits on human activities and quality of life, and limits on commercial/industrial activity and community development. Water, itself, is plentiful on earth, covering 71% of its surface; however, only 0.5% of the world’s water resources are available to provide for the freshwater needs of our planet’s ecosystem and population. The scarcity problem is a result of the amount of water of adequate quantity and quality available in a locale relative to human needs in that locale. As urban planners, agriculturalists, industrialists, and others look to the future, they ask the question, Where’s the water?. At least a portion of the answer, in many situations, is the reuse of treated municipal wastewater for nonpotable and/or potable uses. The use of recycled water has been shown to be safe, cost-effective, and sustainable.

Drivers for water reuse projects include the following:

• Water stress (need for water),

• Conservation of existing potable supplies (reduction of fresh water use),

• Pollution abatement,

• Lack of a reliable water supply alternative,

• Need for a cost-effective new water supply alternative, and

• Environmental restoration.

2.0     THE WATER REUSE OPPORTUNITY

Water reuse is not new. We have been reusing water since the beginning of time, we just do not think of it that way. The same water molecules consumed by prehistoric species are largely still the same molecules with us today. It is the contaminants that are introduced to the water through various types of use that need to be reduced to acceptable levels before the water can be used for beneficial purposes. Virtually all uses of water, natural or by man, add contaminants to water.

The breakthrough in modern water reuse thinking and opportunities is that now we, too, can mimic or duplicate nature’s processes of removing contaminants from water. Some water might not even need much treatment after being used once, depending on its quality and its planned subsequent beneficial use.

Customizing water reuse project approaches and solutions based on how the treated water will be used (i.e., its end use) is a prevalent/common strategy in the development of multiple reuse solutions. This is termed fit-for-purpose reuse solutions. Water reuse is currently being considered as a potential solution for various water management needs throughout the world. The challenge has been in the implementation of water reuse solutions that are robust, cost-effective, and safe with regard to public health and the environment.

3.0     DEFINITIONS

Recycled water is municipal wastewater that has been treated to meet specific water quality criteria with the intent of being used for beneficial purposes. The terms, recycled water and reclaimed water, have the same meaning and are often used interchangeably, depending on geographic location. Municipal wastewater is domestic wastewater that may include commercial and industrial wastewater.

3.1     Uses and Delivery Methods

These are numerous technical terms used to explain the different uses and delivery methods of recycled water. These include the following:

• Augmentation is the process of adding recycled water to an existing raw water supply (e.g., a reservoir, lake, river, wetland, or groundwater basin);

• Beneficial reuse is the use of recycled water for purposes that contribute to the water needs of the economy and/or environment of a community;

• Environmental buffer refers to a groundwater aquifer or surface water reservoir, lake, or river to which recycled water is introduced before being withdrawn for normal drinking water treatment before potable reuse. In some cases, environmental buffers allow for (1) response time in the event that the recycled water does not meet specifications and (2) time for natural processes to affect water quality. Where tertiary effluent is applied by spreading for groundwater recharge, the environmental buffer provides both treatment and storage;

• Groundwater recharge occurs naturally as part of the water cycle and/or is enhanced by using constructed facilities to add water (such as recycled water) into a groundwater basin;

• Potable water is drinking water that meets or exceeds state and federal drinking water standards; and

• Dual water system refers to two separate distribution systems, one that supplies potable water through one distribution network and one that supplies nonpotable (recycled) water through another within the same service area.

3.2     Water Reuse Options

There are the many technical terms, often used interchangeably, to explain the different options for water reuse that a community could choose from. These include the following:

• Potable reuse refers to recycled water that has received sufficient treatment to meet or exceed federal and state drinking water standards and is used for potable purposes;

• Nonpotable reuse refers to the use of recycled water that is used for nonpotable purposes such as irrigation, industrial applications, toilet and urinal flushing, and so on;

• De facto potable reuse is the downstream use of surface water as a source of drinking water that is subject to upstream wastewater discharges (also referred to as unplanned potable reuse);

• Planned potable reuse is an intentional project to reclaim water for drinking water. It is sometimes further defined as either direct or indirect potable reuse (IPR). It commonly involves a more formal regulatory approval process and public consultation program than is observed with de facto or unacknowledged reuse;

• Indirect potable reuse is the introduction of advanced treated water to an environmental buffer such as a groundwater aquifer or surface waterbody followed by normal drinking water treatment. Indirect potable reuse can also be accomplished with tertiary effluent when applied by surface spreading (i.e., groundwater recharge) to take advantage of soil aquifer treatment; and

• Direct potable reuse (DPR) is the introduction of advanced treated water directly to a potable water supply distribution system downstream of a water treatment facility or to the source water supply immediately upstream of a water treatment facility.

3.3     Water Types and Quality

The following terms are often used to define the types of water or different qualities of water:

• Advanced water treatment is a general term used to describe the overall process and procedures involved in the treatment of wastewater beyond secondary treatment to produce advanced treated water;

• An advanced water resource recovery facility (WRRF) is a WRRF at which advanced treated water is produced. The specific combination of treatment technologies used will depend on the quality of the treated wastewater and the type of potable reuse (i.e., IPR or DPR);

• Advanced treated water is water produced from an advanced treatment facility for DPR and IPR applications that augments drinking water supplies;

• Graywater is the term used to describe water segregated from a domestic wastewater collection system and reused on-site. This water can come from a variety of sources such as showers, bathtubs, washing machines, and bathroom sinks. Water from toilets or wash water from diapers is not considered to be graywater. Kitchen sink water is not considered graywater in many states. Many buildings or individual dwellings have systems that capture, treat, and distribute graywater for irrigation or other nonpotable uses;

• Raw water is surface or groundwater that has not gone through an approved water treatment process;

• Domestic wastewater is used water sourced from washing our food, dishes, clothes and bodies, and toilet flushing; and

• Industrial wastewater and commercial wastewater are the liquid wastes generated by industries, small businesses, and commercial enterprises and can be discharged to a sewer upon approval of a regulating authority. Some industrial wastewater may require pretreatment before it can be discharged into the sewer system, whereas other industrial and commercial wastewaters are explicitly excluded. Controlling the release of harmful chemicals into the wastewater collection system is known as source control.

3.4     Treatment Technology

There are terms used to describe the different types of water treatment technology that can be used to create recycled water. Some of the most common terms are defined as follows:

• Advanced oxidation is one of the processes that can be used as a treatment process in advanced water treatment systems. One example of an advanced oxidation process is the use of hydrogen peroxide (H2O2) and UV light in combination to form a powerful oxidant that provides further disinfection of the water and breaks down some health-significant chemical constituents;

• Dual-media filtration is a filtration method that uses two different types of filter media, typically sand and finely granulated