The Environment Writer

To observe World Water Day, I am publishing a short white paper I wrote on greywater and wastewater (blackwater) recycling geared toward the Chicago, Illinois area. Currently, water recycling is hindered in most places by cumbersome or non-existent state and municipal regulations. As water becomes a scarcer and more expensive resource, the practical efficiency of water recycling, both greywater and wastewater is being explored and implemented at high levels of technology.

Greywater Reuse

Definition and Overview

Greywater (also spelled as graywater) is wastewater from showers, bathtubs, sinks, washing machines, and dishwashers. Greywater is generally the wastewater from a household that does not flow out of a toilet (sewage/blackwater).

Greywater accounts for about 60%-80% of the outflow produced in homes. It contains little or no pathogens and 90% less nitrogen than wastewater (toilet water). Because of this, it does not require the same treatment process.

Greywater reuse is currently utilized mostly on small residential scale, with the outflow primarily going to landscaping irrigation.

Recycling Methods

Greywater plumbing must be designated and separated from blackwater plumbing. It is currently used either for irrigation and landscaping, which is fairly simple and inexpensive, or for flushing toilets, which requires greater expense, sterilization equipment and testing. The same technology currently used to create flushing water (see Mercy Homes Chicago) could be used to make drinkable water, but no sites have been permitted for turning it into drinking water in the Chicago area.

Systems require a duplicate and separate set of pipes for greywater to be differentiated from wastewater.

Precautions for non-potable recycling include minimizing storage time to prevent contamination. As human contact should also be eliminated with systems that do not sterilize the water, under-soil drainage is the preferred method to eliminate pooling and maximize natural bacteria breakdown by the soil.

Household greywater recycling diagram (homeevol.com)

Benefits

Greywater pipe separation is a relatively easy low cost when planned into a new smaller-scale residential construction. Cost and space savings can even be gained by reducing the wastewater treatment system, especially for septic systems.

Other Potential Benefits:

1. Reduces the amount of potable, fresh water used by households.
2. Reduces the flow of wastewater entering sewer or septic systems.
3. Minimizes the amount of harmful chemicals used by homeowners.
4. Supports plant growth without using expensive potable water.
5. Helps recharge groundwater when applied outdoors.
6. Raises public awareness of natural water cycles.
7. Saves money on water bills.

Challenges:

Separate greywater piping systems are exponentially more expensive as a building becomes larger than one story or if it is a retrofit of an existing unit.

Municipal and state codes are a hindrance to greywater reuse. In Chicago, special permitting by the Dept of Public Health has allowed (as of 2010) only two buildings to reuse greywater for toilet flushing. Illinois Plumbing Code, Illinois Private Sewage Licensing Act and Code currently prohibit discharging of greywater to ground surface and/or for irrigation. (See below for best policy examples elsewhere in the United States.)

Although cleaner than wastewater, greywater reuse systems can carry contaminants or become a pathogenic hazard, insect breeding sites, or odor nuisance if not carefully executed. Receiving areas should be monitored for impacts, and best practices should be followed and research and testing on benefits and risks should be pursued.

Resources:

• Greywater Recycling from Brac System

• Oasis Design Greywater Information Central

• McHenry County Groundwater Protection Program – Section 5 Wastewater

Best Chicago Area Examples:

• Yannell Net Zero Energy House: LEED Platinum zero net energy home that collects used washing machine water to flush toilets in the home. Chlorine, microfiltration and UV light are means of disinfection.

• Margot and Harold Schiff Residences, 1244 N. Clybourn, Chicago, IL (Mercy Housing Lakefront): Affrordale housing that recycles greywater to flush toilets in a 96 unit residential building, with added rainwater collections system. UV light disinfection primary means of treatment.

Best Practice Guidelines and Polices:

National standards: Green Building Standards Guide by the National Association of Home Builders was recently updated to include greywater reuse as option where permitted.

State policy models: Two different policy approaches noted, “design standards model” vs. “performance standards model.” Design standards tend to reduce demand of projects because of strict design guidelines, but produce results much closer to estimates. Performance standards policy models encourage innovation in cost and performance, increasing demand, but a measurable system of oversight and monitoring must be in place because the outcomes are not as predictable.

• California Guidebook – Design standards model, also part of the State Plumbing Code making it uniformly legal to install greywater reuse systems.

• Arizona – Performance standards model, statewide adoption of greywater for outdoor irrigation. Also a Greywater Conservation Tax Credit for residential incentivization.

• Massachusetts – Allows permitting for new construction for greywater flushing use.

Wastewater Reuse

Definition and Overview

Wastewater, also known as blackwater, is toilet waste. Wastewater recycling is typically considered on a much larger scale than greywater reuse due to the higher risk of contamination and mishandling on a small scale. There are four potential uses for reused wastewater, ranked in infrastructural difficulty of processing.

1. Turf irrigation
2. Industrial
3. Agricultural irrigation
4. Drinking water

The theory behind most current wastewater reuse is to apply recycled wastewater to lower value uses (ie turf irrigation) that would otherwise utilize high value potable water applications. However, there are some highly advanced systems, the largest of which is in Orange County, CA, which do use reclaimed wastewater for municipal drinking water (see below).

Recycling Methods

Wastewater can be reclaimed by centralized wastewater treatment plants, decentralized smaller scale plants, or by satellite plants that can be located upstream from the central plant to intercept certain amounts of wastewater before entering the sewer system or by tapping into trunk sewers.

The simplest uses such as turf irrigation (gold courses, cemeteries) and industrial uses (drillbit cooling, concrete cutting, ground stabilization) do not have as stringent water quality needs and can be treated much the same as the Metropolitan Water Reclamation District of Greater Chicago (MWRD) current secondary standards, which is not disinfected.

Agricultural uses require somewhat more stringent standards due the concern of foodborne illnesses, but this use is currently permitted under Illinois law. It is not clear what standards would be needed, but a higher level of secondary standards than above would by most reports be preferred.

In the most difficult method to create drinking water, such as the case in Orange County, California, wastewater is sent through filters, UV light sterilization, reverse osmosis and diluting basins before being injected into the groundwater for further dilution and filtration. The process takes two to three months before the water reaches the tap.

Benefits and Challenges

Although many obvious water conservation benefits are the similar to greywater reuse, benefits of wastewater recycling are realized best on large scale processes, both in terms of centralized treatment and large scale agricultural, industrial or public use.

One of the greatest reported challenges to reusing wastewater is the psychological deterrence by the public of using reclaimed wastewater. Therefore, the most immediate potential benefits would be the lower-value use, such as the turf irrigation or industrial uses.

To get to drinkable standards requires a large upfront investment, although the cost may be considered reasonable relative to alternatives in some situations. The Orange County project cost $481 million to build, but the alternatives included desalination (up to four times the cost) in addition to the cost of new waste piping facilities to be built into the Pacific Ocean.

The McHenry County Groundwater Action Plan estimated that pumping recycled wastewater for golf course irrigation in the Village of Addison would cost the golf courses $0.92/1000 gallons, and $1.75 for other irrigation and industrial uses. This is a major incentive as current water rates for the study area were $4.05/1000 gallons.

Other challenges include concerns over chloride, nutrients and pharmaceutical products in the wastewater, which would require further treatment and/or monitoring for various applications.

Best Examples and Resources

• McHenry County Groundwater Protection Program – Section 5 Wastewater

• Village of Algonquin: Contractor Handbook – Use of Treated Effluent as a Non-Potable Water Source• Orange County Water District’s Groundwater Replenishment System

• GE’s Advanced Water Reuse and Recycling

The success of the LEED program is its compatibility with economic efficiency, direct monetary benefits to stakeholders through cost savings, marketability to businesses, and consumer pressure for continued growth of the green building industry. The program design, which is voluntary and constantly evolving, requires high levels of environmentally friendly design techniques to help ensure long-term economically sustainable building development.

The Leadership in Energy and Environmental Design (LEED) certification has become the pre-eminent green building rating system since its inception more than a decade ago. The certification process as developed by the US Green Building Council (USGBC) is described as ‘a voluntary, consensus-based national rating system for developing high-performance, sustainable buildings.’ In the LEED Version 3 system, which is being introduced in the spring of 2009, the USGBC is expanding the rating system from three to nine certification tracks such as Commercial Interiors and Neighborhood Development. During certification, the building project must achieve a certain number of requirements in categories such as energy efficiency, water efficiency and sustainable site selection. The more points the project achieves above the minimum, the better rating the project receives.

Lifetime Cost Savings: Although there are sometimes higher upfront costs associated with LEED certification, one of the most obvious benefits of the program is the direct cost savings over the lifetime of the building. Projects that significantly increase energy efficiency and reduce water and sewage usage will save money through reduced operational costs and city fees. Healthier environmental conditions increase inhabitant productivity. The program gives points for siting projects in areas with existing infrastructure and for reusing materials, which can reduce upfront costs. LEED also gives points for developing areas like brownfields, for which numerous tax incentives and government breaks are typically available.

Enhanced Marketing Opportunities: LEED certification also creates enormous marketing opportunities. As consumers see the advantages of lower environmental externalities, healthier lifestyles and reduced prices of environmentally friendly items, consumer preference is quickly changing to support green and energy efficient products. Companies that employ LEED certification show their commitment to sustainable development and can use their green credentials to a great advantage in advertising and public relations. In fact, the growing green market is so big that there are now complaints of green-washing in which products falsely claims to be environmentally friendly. The advantage of the popularity and transparency of LEED is that it enjoys high levels of consumer confidence in maintaining leadership in environmental development and promoting legitimately high thresholds of sustainable design.

Driving the Green Building Market: LEED also has the advantage that is an economically self-perpetuating program. As confidence grows and more projects are completed, the green building market grows in stride. Although demand for green products is increasing, the cost and availability of materials is increasing faster, driving their prices down and encouraging further growth in the green building industry. The green building market is predicted by 2013 to double to $96-$140 billion in the US. At the same time wholesale suppliers like Green Depot in New York City and Green Maker Supply in Chicago are increasing volume and reducing supply costs for builders at all levels. This increasing economy of scale works to speed growth and create an important market share.

The LEED program has found success not only because of the economic and marketability factors, but also because of its institutional design characteristics. First, it is a voluntary program. This choice allows the elimination of the deadweight loss that would result by government mandate and allows it projects that market their certification to be much more persuasive. Secondly, it is program that is continually improving by becoming stricter and more detailed. For example, in the most recent update LEED Version 3 now includes regional specifications to become more applicable to the intricacies of regional geography and climate conditions. It is finally important that USGBC never claims that LEED certification is an ideal. Even its highest level of Platinum certification, it describes it in relative terms, saying, ‘Platinum buildings are highly energy and resource efficient, provide superior indoor comfort for the building’s occupants, and dramatically reduce CO2 emissions…’ This orientation is truthful in practicality and also eliminates many criticisms that LEED is not comprehensive. In addition, it leaves room to develop the program and continue to fulfill its self-described title of ‘leadership’.

Still, there are obstacles to initiating widespread acceptance of LEED and green building in general. The payback period of 10-15 years makes many companies balk at the upfront costs as they often have business models limited to 5 years. To help this problem, there can be incentives set up by the up and coming ‘green banks’ that provide lower cost financing to green projects as well as companies who provide projects paid for solely by the cost savings themselves. Finally, providing incentives to commit institutions for these longer periods may be worthwhile to communities because the companies develop long-term vested interests in their location and geographical networks. After all, one of the key ideas in sustainable development is the focus on long-term economic growth, not just the short term.

The USGBC has created a market-based certification process that encourages and drives the green building industry to expand and continually meet higher standards. LEED demonstrates its place in an efficient economic system by providing long-term paybacks, enhancing marketing opportunities for organizations and encouraging consumer preferences for sustainable and environmentally friendly economic growth. As the market grows, the USGBC has positioned LEED so it can grow dynamically with emerging trends and advancing technologies to maintain its leadership status in environmental and energy design.