Biosolids -- a growing field
- By Reed Margulis
- Oct 01, 1999
In 1997, basketball coach Dean Smith of the University of North Carolina at Chapel Hill became the winningest coach in the history of college basketball, surpassing Adolph "The Baron" Rupp, legendary coach of the University of Kentucky Wildcats. When football fans think of great coaches, Don Shula, Tom Landry, Vince Lombardi and Bear Bryant come to mind. They all produced successful programs that they were able to successfully sustain for many years.
So, what do these bits of sports history and trivia have to do with biosolids recycling programs? They have to do with sustainability. And whether one is talking about sports, biosolids or other endeavors, how, or if, they will survive are always important questions. In fact, the words "survivability" and "sustainability" are, for all practical purposes, synonymous.
Over the past 10 years, beneficial biosolids recycling has increased more than twofold - from less than 30 percent to almost 60 percent of all biosolids generated from wastewater treatment operations.
Accusations of greenwashing
Unfortunately, the growth in popularity of biosolids recycling has not been matched by a parallel growth in the general public's understanding of the safety and community benefits associated with biosolids recycling. In fact, as biosolids recycling has become more commonplace, it has attracted more organized and more vocal opposition, as well as mass-media attention. In many locations, some opponents (who consider it "greenwashing") now view the term biosolids with cynicism.
Usually, this situation has occurred when people substitute the word biosolids for the term sewage sludge. Nothing could be further from the truth, however. Biosolids are no more untreated sewage sludge than gasoline is crude oil.
Webster's Collegiate Dictionary, 10th Edition, defines biosolids as "solid organic matter recovered from a sewage treatment process and used, especially as fertilizer." The key aspect of the definition of biosolids is that they are "used, especially as a fertilizer." In this context, the residuals (wastewater solids, sewage sludge, etc.) have been treated to quality criteria levels necessary for recycling - primarily as a nutrient source in agricultural applications.
The term biosolids was coined in 1991 to replace the commonly used description "sludge," and adopted by the U.S. Environmental Protection Agency (EPA) in 1996 to better reflect the positive effects of more than 20 years of effort to clean the nation's waters through a massive wastewater treatment program.
The conversion process
It is important for all of us to realize and not forget the significant amount of time, money and resources that are expended by the wastewater treatment plant (WWTP) to convert untreated sewage sludge into biosolids so that they meet all of the applicable federal, state and local regulatory requirements for use or disposal. When we flush our toilets or wash kitchen wastes down the sink, do we know or have any understanding of what happens next, or how much it is going to cost? Conservative estimates show that 25 percent to 50 percent of a WWTP's budget is devoted to solids and sludge management coupled with the costs associated with disposal or beneficial biosolids recycling.
The WWTP is a very cost-effective and efficient operation processing and treating domestic, commercial and industrial, usually pretreated, wastewaters. Essentially, WWTP unit operations are designed to treat the wastewater by removing solids to produce as clean an effluent (discharge to surface waters) as possible. These unit operations consist of screening and grit removal, biological and chemical treatment, clarification - secondary solids separation - and disinfection. The solids and sludge generated and removed during the wastewater treatment process can be handled in a variety of ways.
The two most commonly used methods for sewage sludge treatment at WWTPs are aerobic digestion and anaerobic digestion. Occasionally, alkaline - usually lime - treatment is used. Under normal circumstances the digestion and/or alkaline treatment processes are sufficient to convert the sludge into biosolids. Sludges and biosolids are sometimes dewatered or further processed via additional alkaline treatment and drying, composting (envessel, windrowing or aerated static pile), or thermal drying. The degree of treatment, and the type of treatment, are determined by feasibility and market studies.
To be of value, these studies must be based upon location as well as the sludge and biosolids treatment methods employed by the WWTP or its contractor. For example, in rural areas where agricultural land is available, Class B biosolids are the product of choice among the agricultural community. Farmers want these biosolids because of their high nutrient value - saving farmers about $100 per acre in fertilizer costs - and associated increased crop yields. Additionally, Class B biosolids can be applied as liquid or cake in a similar manner to fertilizers and manures.
Numerous case studies have shown that the use of Class B biosolids is the most economical for the WWTP and most beneficial to the farmer and community at-large. In more populated urban areas, it may be necessary to produce Class A or Exceptional Quality (EQ) biosolids. EQ biosolids will be essential for distribution and marketing, especially for bagged products. However, in many areas, situations related to location, public perception and cost have resulted in sludge disposal via incineration or landfilling.
Class A and Class B refers only to pathogen reduction levels per 40 Code of Federal Regulations (CFR) Part 503. Class B biosolids have associated site restrictions for public access, animal grazing and types of crops. However, it is extremely important to realize that the use of either Class A or Class B biosolids (with restrictions) is safe and protective of public health and the environment, provided good management practices and all of the applicable provisions of Part 503 are followed. Additionally, EQ biosolids refers to a type of biosolids that not only is Class A, but achieves vector attraction reduction and meets the highest quality criteria for pollutant concentrations as stipulated in Part 503.13.
Until the general public understands this and uses the term properly, the biosolids recycling industry will continue to have problems and be rightfully accused of greenwashing. Therefore, it is essential that the general public be able to differentiate between sludge and biosolids.
Misunderstanding among consumers and the media about biosolids recycling has spawned sensationalized and inaccurate coverage in local and national media. Despite the extensive body of research that clearly supports the safety, environmental and community advantages of biosolids recycling, public misperceptions, where they exist, make it difficult - if not impossible - to implement, expand or realistically expect to sustain biosolids recycling management programs.
We all know that perception is reality - if people form negative opinions or have concerns, then there are going to be problems ahead! With biosolids recycling, the public perception issues have primarily been related to safety (public health and the environment) and aesthetics. According to a 1998 survey, less than 1 percent of people in the United States knew about biosolids or were concerned about biosolids recycling.
However, more than 50 percent of those who were knowledgeable said they were concerned not so much with the substance of the regulatory requirements, but with the lack of oversight, compliance and enforcement with those regulatory requirements. The bottom line is that any biosolids recycling effort must be done correctly. Otherwise, projects will suffer the ramifications of liability and negative public perception. Proper management must include communication and the establishment of a relationship of trust with the public - without these elements, any project will eventually fail.
Addressing the issues
In response to these concerns, the National Biosolids Partnership (NBP) was formed in 1997. The NBP consists of the Association of Metropolitan Sewerage Agencies (AMSA), the EPA and the Water Environment Federation (WEF). In 1998, the U.S. Congress appropriated $900,000 for the NBP; much of it was earmarked for development of an environmental management system (EMS) for biosolids.
EMSs are increasingly being implemented on a voluntary basis by both profit and non-profit organizations to help improve their overall environmental performance and product quality. Many of these organizations and companies use the International Standards Organization (ISO) certification of ISO 9000 (products) or ISO 14000 (environmental). The need to apply a similar approach to biosolids recycling has recently been endorsed by the NBP and WEF's Residuals and Biosolids Committee.
Maine is considering legislation to encourage the use of the EMS concept to enhance regulatory compliance. The bill would establish a state policy encouraging facilities to develop and implement an EMS that conforms to international standards. The bill requires the commissioner of environmental protection to implement an incentive program to encourage facilities to implement certified EMSs by offering regulatory relief to those facilities. Additionally, the National Science Foundation's research arm, the National Research Council (NRC) has also recommended the establishment of an EMS for biosolids.
In 1996, the NRC concluded in a published report that properly treated, recycled biosolids are both safe and effective for fertilizing food crops. The report reiterated the nutrient value and improved soil properties, such as water retention and greater stability, that result from applying biosolids. The NRC report also concluded that current regulations are adequate to provide the needed margin of safety for consumers.
The EMS for biosolids will be a voluntary program. One of its main functions is to help ensure the responsible management of biosolids and to enhance, secure and sustain the local community's and general public's understanding and support of biosolids use or disposal practices - whether the option is land application, distribution and marketing, surface disposal, co-disposal, monofills or incineration.
The production of consistently high quality, predictable products - from controlling what materials are allowed to flow into wastewater treatment plants (via pretreatment programs under 40 CFR Part 403, through generating and further treating the solids and sludge at the plants - is vital to a successful EMS. Additionally, proper transportation, storage and use of the resultant biosolids or biosolids product(s) are an equally important consideration under the EMS. Responsible management of biosolids will, in turn, enhance and expand public understanding and support, which are vital to the success and sustainability of any biosolids management program.
Former Speaker of the U.S. House of Representatives Tip O'Neill once said that "all politics is local." Each EMS for biosolids must incorporate local oversight and involvement into each program to help achieve ongoing recognition within the community that biosolids projects meet strict safety and health requirements. The EMS framework also provides an opportunity for the public to better appreciate the tremendous value of biosolids as a resource. The EMS for biosolids is the key to public understanding of the safety and community benefits associated with biosolids recycling, which is absolutely essential to achieving, nurturing and sustaining public support - at both the national and local levels.
Water Environment Federation's biosolids page
Click here to post comments about this topic, and read what others have to say.
This article originally appeared in the 10/01/1999 issue of Environmental Protection.