MWRD-Control of Phosphorus

Phosphorus (P) is an important nutrient for terrestrial and aquatic ecosystems. It is an essential element required for global food security and its demand has been increasing worldwide due to increasing food needs of the world’s growing population. At the same time, use of P containing compounds has been increasing in the manufacturing, processing industry and in commercial and household cleaning (sanitizing products like laundry, dishwasher, or other heavy-duty cleaners). Today, the worldwide P supply is obtained mainly from mined rock phosphate; existing rock phosphate reserves are declining and could be exhausted in the next 50-100 years per various scientific projections including the U.S. Geological Survey (USGS). The future of this non-renewable, essential element has received little public attention. Recently, it has been recognized that P in wastewater is largely an untapped resource, allowing wastewater to possibly serve as a sustainable supply of this scarce nutrient. Parallel to these developments, the wastewater industry is facing stricter regulations on nutrient discharges, because under certain biological and natural conditions, excess P in wastewater and aquatic environments can contribute to eutrophication, which in turn can lead to an undesirable condition known as hypoxia.

A well-publicized example of hypoxia in surface waters is the dead zone in the Gulf of Mexico. The Mississippi River Gulf of Mexico Watershed Nutrient Task Force created an action plan, which includes goals for reducing nitrogen and P-loading by 45 percent in an effort to reduce the size of the hypoxic zone in the Gulf of Mexico. To achieve these goals, there is pressure on the agriculture industry to reduce the non-point source of nutrients. Since wastewater treatment plants (WWTPs) typically receive P from the domestic and industrial wastewater and stormwater runoff and ultimately discharge some P in the plant effluent to the waterways, it is anticipated that stricter effluent nutrient limits will be imposed on WWTPs in the Mississippi River Basin. Initially, the Nutrient Task Force estimated that the 45 percent nutrient load reduction goal could be achieved by 2015; however due to regulatory complexity, they now believe that it will take much longer.

In January 2001, the United States Environmental Protection Agency (USEPA) published water quality criteria for nutrients in our Nation's waters (Section 304). USEPA’s 2001 Section 304 criterion was an occasion for states to re-evaluate the adequacy of their own water quality standards for nutrients. In response, the Illinois Environmental Protection Agency (IEPA) prepared a Nutrient Standards Development Plan in August 2003, which was approved by Region V of the USEPA. This plan called for the study of water quality problems caused by nutrients, preparation of a proposed rulemaking and eventual adoption of standards by the Illinois Pollution Control Board (IPCB) in 2008.

Prior to 2008, the IEPA/IPCB promulgated interim P rules for new and expanding WWTPs as well as water quality standards for lakes and streams immediately upstream of lakes. The interim P rules require an effluent limit for P, expressed as Total P (TP) of 1.0 mg/L for the new or expanded WWTPs that are capable of treating greater than 1.0 million gallons of sewage per day. It is estimated that the interim TP effluent limit is reducing the P load discharged to Illinois streams by 200 to 300 tons per year. Due to the limited number of new or expanded WWTPs in Illinois, the cost impact associated with the interim TP effluent standard is not large statewide.

The IEPA has yet to develop comparable numeric water quality standards for TP in rivers and streams. This is a challenging task due to the lack of a correlation between nutrient concentration and environmental impact in surface water bodies in Illinois. In response to sustained demand and follow-up by the USEPA, the IEPA is working with stakeholder groups to develop a new, more stringent narrative standard for nutrients while work continues to determine whether a supportable science-based numeric water quality standard can be established for TP in Illinois rivers and streams.

The upshot of these Illinois regulatory efforts likely will be more stringent effluent limitations in the future WWTPs like the District’s, yielding greater costs to remove TP received from our users. These new costs could amount to several hundred million dollars statewide (per Illinois Association of Wastewater Agencies).

Success in Limiting P Sources in Domestic, Commercial and Industrial Wastewater

In 1970, the detergent industry voluntarily agreed to an 8.7 percent limit on the P content in its products. According to a USGS report, in 1972 the U.S. Congress desired to end the manufacturing of phosphate detergents. However, concerns were raised regarding the acceptability of leading substitutes at the time. As a result, no P limiting federal legislation was passed.

In 1971, the City of Chicago implemented a ban on the sale of residential laundry products containing P. This led to a measurable reduction in the pounds of TP entering the Metropolitan Water Reclamation District of Greater Chicago’s (District) WWTPs as well as a reduction in the treated effluent P concentrations. Today, all such products and most other home cleaning products remain P free.

There are at least 25 states that have enacted legislative bans on the use of P in cleaning agents over the past 35 years. Most states have similar requirements, limiting the P content in household laundry products. However, all states allowed P to be up to 8.7 percent in automatic dishwasher detergent (ADWD) products.

In 2005, it was determined that a scientific basis for the 8.7 percent allowance of P in ADWD products may no longer be valid, given the availability and acceptability of ADWD products that do not contain P. Thus, the Illinois Association of Wastewater Agencies (IAWA) proposed House Bill 1502 in the Illinois General Assembly in February 2005 to help reduce TP discharges to Illinois lakes, reservoirs, rivers and streams. This proposed legislation was intended to limit P content in cleaning agents used in businesses and homes, primarily those ADWD products that still contain P. The House Bill resulted in a ban on residential ADWD products containing greater than 0.5 percent P. It went into effect in July 2010. Additionally, an industrial standard limiting the P content in commercial and industrial detergents will go into effect in the summer of 2013. According to the American Cleaning Institute information, major manufacturers such as Procter & Gamble, EcoLab etc. have voluntarily agreed to manufacture ADWD products with a new low P content (0.5% by weight) nation wide effective July 1, 2013.

In addition to detergents, amendments to the Illinois Fertilizer Act of 1961 (HB6099), banned P containing fertilizers for lawn and turf effective July 2011. Legislative initiatives over the years have been the reasons that many threats to the environment and public health have been eliminated. Lead in gasoline, PCBs in oils used in electrical equipment, DDT as a pesticide, are just a few of the examples.

P can enter waterways through point sources, such as industrial facilities, and non-point sources, such as agricultural and stormwater runoff. Most of the TP discharged from WWTPs comes from human excreta and food waste, (approximately 60 percent). Other sources of P are from household products (approximately 10 percent) and commercial and industrial products and applications (approximately 30 percent). Source control measures appear to be logical and prudent ways to reduce the TP entering the aquatic environment.

In consideration of the future P scarcity and a looming threat to global food security, it is important not only to recover P from the wastewater resource but also to concentrate efforts on P demand reduction and source control measures by adopting the following practical suggestions in daily routine.

Suggestions for Reducing Phosphorus in Our Terrestrial and Aquatic Environment

Phosphorus Contributors	Tips to Reduce/Recover Phosphorus
Domestic	Use low- or non-P dishwashing liquids and soaps
	Efficiently use dishwasher; either reduce frequency of use or operate only when dishwasher is full capacity
	Prevent Phosphorus from Entering Storm Sewers
	Wash cars on grassed areas and not on roads or driveways Collect leaves, grass clippings, and other yard waste from street drains and gutters. Check fall leaf and brush pick-up dates to take advantage of beneficial composting practices Use low- or non-P lawn fertilizer Leave grass clippings on the lawn; mulch yard waste if possible using mulching mower as it reduces the need of fertilizers Restore natural shoreline or stream bank habitat to prevent P runoff from entering surface waters or storm sewers Collect your pets poop and dispose of properly, prevent dogs from urinating on roads or sidewalks, make sure pets urinate on grassed areas so that P-enriched urine doesn’t runoff directly to storm sewers
Drinking Water Treatment Plants	Optimize the addition of P to the drinking water supply to prevent corrosion
Businesses, Hospitals, Schools, Restaurants, and Institutions	Cleaning and Sanitizing
	Establish purchasing criteria for cleaning products, buy low- or non-P products Use proper concentrations of cleaners and detergents as directed by manufacturers Use dry cleaning practices prior to wet cleaning
Industrial/Metal Finishers	Metal Preparation, Finishing, and Painting
	Evaluate alternative low- or non-P processes Reuse/Recycle water when possible Reduce spills, leaks, and tank overflows Use proper concentrations as recommended Keep process solutions in their tanks by reducing carryover Use deionized/RO water for process baths and rinses Make sure process controls are calibrated and maintained Make sure spray nozzles are cleaned and maintained Look for ways to improve efficiencies so that less phosphorus is used in the first place
	Recover Phosphorus from Wastewater Effluent
	P is a resource, explore and evaluate if possible to recover P from the use of phosphoric acid/concentrated phosphates in industrial processes; these measures may be economical and help the environment at the same time
Industrial/Food Processors	Food Processing
	Keep food by-products off the floor and out of drains Use dry cleaning practices prior to wet cleaning Reduce spills, leaks, and tank overflows Use an automatic clean-in-place (CIP) system Investigate reusing/recycling by-products for animal feed, composting, or land spreading, promote environmental stewardship at your industry
	Sanitizing
	Investigate low- or non-P sanitizing chemicals Reduce spills, leaks, and tank overflows Look for ways to improve efficiencies so that P demand can be reduced
	Recover Phosphorus from Wastewater Effluent
	P is a resource, explore and evaluate if possible to recover P from the use of phosphoric acid/concentrated phosphates in industrial processes; these measures may be economical and help the environment at the same time

The District is committed to its goal of ‘Protecting Our Water Environment’ and is following a sustainability approach to further reduce TP. Under this approach, the District is planning to recover P in the form of a high value fertilizer product from its wastewater in the near future and is pursuing many other initiatives such as ‘Biological P Removal’ and ‘P Source Control’ with the goal of helping create a more sustainable future.

For more information on the subject, please contact the District’s Public Affairs Office at 312-751-6633.

Prepared by the District, 3-14-2013, based on research conducted by the District and review of the following: