BIOSOLIDS AND RESIDUALS TREATMENT AND MANAGEMENT OPTIONS: A COMPARATIVE COST EVALUATION

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BIOSOLIDS AND RESIDUALS TREATMENT AND MANAGEMENT OPTIONS: A COMPARATIVE COST EVALUATION Robert G. O Dette Mr. O Dette holds a B.S. and M.S. in Civil (Environmental) Engineering and has more than 25 years of experience in wastewater treatment, and residuals and biosolids management.

1 BIOSOLIDS AND RESIDUALS TREATMENT AND MANAGEMENT OPTIONS: A COMPARATIVE COST EVALUATION Robert G. O Dette Mr. O Dette holds a B.S. and M.S. in Civil (Environmental) Engineering and has more than 25 years of experience in wastewater treatment, and residuals and biosolids management. He is a registered professional engineer and a Diplomate of the American Academy of Environmental Engineers. Mr. O Dette has testified before the U.S. Congress and is Chair of the Water Environment Federation s Residuals and Biosolids Committee. Address: Synagro Technologies, Inc., 149 Yadkin Valley Road, Advance, North Carolina, USA Tel: (336) Fax: (336) e- mail: bob@biosolids.com ABSTRACT Determining the actual cost of doing any thing is difficult. This is especially true for wastewater treatment operations, particularly those operations that involve solids handling. This paper provides an overview of the dilemma of determing the most cost effective option for biosolids use or disposal. Various management options and cost evalation techniques are discussed using selected case histories. KEYWORDS: Biosolids, Wastewater, Treatment, Perception, Composting, Land Application, Costs. INTRODUCTION Those involved with wastewater treatment are all familiar with the classical engineering diagrams showing the various unit operations at treatment plants. These units are designed to treat the influent wastewater to a prescribed level which will ensure that the effluent meets the requirements of prescribed permits, such as the National Pollutant Discharge Elimination System (NPDES) permit in the United States issued to the publicly owned treatment works (POTW). Traditionally, there has been nothing more than an arrow from the clarifiers and/or digesters for solids and/or biosolids treatment, use or disposal. In many POTWs in the United States, wastewater treatment plant operators and superintendents have been, and continue to be, beleaguered by problems caused by an over abundance of wastewater solids and biosolids. One of the certainties of life is that people are going to continue to flush toilets and consequently solids and biosolids will continue to be generated by the POTWs. Compounding this problem is the fact that since the passage of the Clean Water Act in 1972, there have been four rounds of NPDES permits. The NPDES permit requirements have significantly increased over the past 20 plus years. 20 o Congresso Brasileiro de Engenharia Sanitária e Ambiental 4106

2 Thus, with tighter effluent requirements more solids and biosolids are now being generated per capita than in the early 1970 s. Similar situations exist around the world as both populations and environmental concerns increase. In many POTWs, their situation is analogous to the TV commercial showing the man working in a pie factory who eventually runs out of the right size box for the all the pies coming down the line. No matter, the pies keep coming down the line! Ready or not here they come, and so it is at POTWs: the wastewater solids and biosolids keep on coming! And yes, in many POTWs, it is starting to get deep! The questions then become: "Now what are we supposed to do? How much is it going to cost?" In most cases the answers are not pleasant ones for people who are trying to hold on to their jobs or remain in political office. There's no question about it being a tough world out there when it comes to raising sewer rates and/or evaluating biosolids use or disposal options. There are many negative perceptions that must be overcome, such as the NIMBY's (not in my back yard) and NIMTOO's (not in my term of office). To do this successfully is not easy and it costs time and money and is definitely a real cost that most people don't factor in to their equation. DEFINING THE PROBLEM It is important to realize that perception is reality! Some people will look at a beneficial biosolids recycling program and see the positive aspects such as increased crop yields, fertilizer savings to the farmers (US$75 to US$125 per acre), not to mention the savings to the POTW on their treatment, use or disposal costs. However, other people will see the very same project and try to make a negative case saying you are poisoning the land, killing our children, and destroying our environment. Therefore, getting the truth out and educating the public relative to the benefits of biosolids recycling is essential to establishing and maintaining the proper public perception concerning these projects. Again, remember that this activity costs money if it is going to be done right! These projects must be done right or it is really going to result in extra costs down the road, because whenever the wrong option is selected everyone involved loses money or benefits. So back to the original questions of what to do and how much is it going to cost? The United States Environmental Protection Agency (USEPA) has estimated that the cost of solids and biosolids management represents as much as half of the total cost of wastewater treatment. (USEPA, 1985) Table 1 shows some typical biosolids costs as a percentage of the total wastewater treatment costs for selected countries around the world. (Matthews, 1996) 20 o Congresso Brasileiro de Engenharia Sanitária e Ambiental 4107

3 Table 1: Biosolids Costs as a Percentage of Total Wastewater Treatment Costs. COUNTRY CAPITAL % O & M % Australia Austria China France South Africa United Kingdom Table 2 shows typical biosolids treatment costs based upon updated USEPA data. (USEPA, 1984) Table 2: Typical Biosolids Treatment Costs. METHOD * Land Application Composting Landfilling Incineration * 1980 EPA data corrected to 1997 values via Engineering News Record Index Notice the wide range in cost values reported in the USEPA data for each of the options evaluated. What is the reason for this wide disparity? The answer is most likely that all of the costs were not accounted for properly. For example, the December 1993 issue of BioCycle Magazine stated that compost costs vary greatly from about US$30 to US$430 per dry ton! (O Dette, 1996) Do they really vary that much or is there something wrong in the way the data is being evaluated? The author believes that the reasons why cost figures vary all over the board is because these evaluations are not consistent and all costs are not being considered. In most all cases it is not an apples-to-apples comparison, sometimes by design, but mostly out of ignorance and a lack of adherence to valid cost accounting principles. So many times cost data (in terms of dollars per dry ton) are reported via a paper presentation at a technical conference or shown in a professional publication. But how many times are these cost figures compared on an equitable basis to others in terms of power, labor, equipment, transportation, etc.? Make no mistake about it, there is a lot of smoke and mirrors to contend with when someone starts talking about their costs for biosolids treatment, use or disposal. 20 o Congresso Brasileiro de Engenharia Sanitária e Ambiental 4108

4 DETERMINING TRUE COSTS Is it mission impossible to determine the most cost effective biosolids use or disposal option? Of course not provided you scrutinize the evaluation procedure to make sure that each option has been fully and fairly compared to all others. In fact, some effort should be made by the Water Environment Federation (WEF) to develop an Atlas format along the lines of that proposed by Dr. Peter Matthews of Anglian Water so that all biosolids use or disposal options can be analyzed fairly on a consistent basis. For example, in Australia average biosolids treatment costs range from US$100-US$150 per dry ton of biosolids produced with beneficial use (biosolids recycling via land application) costs averaging about US$50 per dry ton of biosolids produced. (Matthews, 1996) Certainly, the capital costs and those ancillary costs associated with overhead, operations and maintenance are the real baseline costs that most people evaluate. There are other "costs" related to public perception and doing things wrong in terms of outreach, public education and public relations. For example, in the mid-1980's, Nashville, Tennessee had a very successful land application program in an adjacent county. It was successful in terms of dollar savings to the city and the farmers in the program. However, things went wrong with public perception in the county and a citizens group eventually shut down the project. Nashville had composting and incineration options to fall back on, but at increased costs. The key point in this scenario is the cost to Nashville, because of a breakdown in public relations in the adjacent county. Table 3 shows a cost comparison for the options used by Nashville. (O Dette, 1996) Table 3: Biosolids Treatment Costs - Nashville, Tennessee, USA. METHOD Land Application 80 Composting 230 Incineration 250 CASE HISTORIES Bristol, Tennessee experienced some similar problems with their land application program in the 1980's and decided to go with an in-vessel compost system that could also handle yard trimmings. This system is currently operating at about US$315 per dry ton (8.5 dry tons per day), but once the system reaches design capacity (14.3 dry tons per day) the cost is expected to decrease on a per dry ton basis. Another in-vessel composting operation at Oceanside, CA was evaluated in the April 1991 issue of BioCycle Magazine. Table 4 shows the cost breakouts with the total cost of US$250 per dry ton. (O Dette, 1996) Table 4: Biosolids In - Vessel Composting at Oceanside, California, USA. ITEM Power 113 Amendment 58 Labor 54 Miscellaneous 25 TOTAL o Congresso Brasileiro de Engenharia Sanitária e Ambiental 4109

5 Nashville, Tennessee used the aerated static pile composting method much like the operation at Site 2 in Silver Spring, Maryland. Site 2 has reported an overall composting cost of US$166 per dry ton which includes revenues from product sales. Table 5 shows a summary of several composting cost comparisons from operations in the United States. (O Dette, 1996) Table 5: Typical Biosolids Composting Costs in the USA. LOCATION Site 2, Silver Spring, Maryland 166 Bristol, Tennessee 315 Oceanside, California 250 Nashville, Tennessee 230 Alkaline stabilization techniques using lime and kiln dust are also options. For example, the N-Viro process was selected at the First Utility District of Knox County (FUD), Tennessee where the product has been used successfully for the mine land reclamation. According to former FUD General Manager, Rick Kirby, the N-Viro process costs are approximately US$250 per dry ton. Cookeville, Tennessee decided to use alkaline stabilization and conducted a pilot test to evaluate various methods. Cookeville selected the RDP (Lime/EnVessel) process and full-scale operating costs have been about US$125 per dry ton! (O Dette, 1996) Costs below US$100 per dry ton are usually not seen except for liquid biosolids recycling land application projects. Memphis, the largest city in Tennessee has conducted very successful land application projects for more than 15 years. Memphis has reported costs consistently below US$100 per dry ton for both their North and South wastewater treatment plants. Memphis is one of the best examples of what can be accomplished technically, politically and economically when it is done right! (O Dette, 1996) Perhaps one of the best evaluations was recently conducted by the Western Carolina Regional Sewer Authority (WCRSA) in Greenville, South Carolina. WCRSA produces about 30 dry tons per day of biosolids. 30% of the biosolids are used for agricultural land application and/or landfill cover, while the other 70% goes directly into a landfill. WCRSA estimates that their biosolids production will be approximately 80 dry tons per day by the year 2015 and has the desire to beneficially recycle 100% of their biosolids. So WCRSA made the decision to evaluate Land Application, Composting, Heat Drying, and Co-Composting. In their evaluation WCRSA looked at three economic considerations: (1) Capital, (2) Operation and Maintenance, and (3) Present Worth. Additionally, WCRSA looked at five non-economic considerations: (1) Reliability, (2) Flexibility, (3) Community Acceptability, 20 o Congresso Brasileiro de Engenharia Sanitária e Ambiental 4110

6 (4) Compatibility, and (5) Complexity. The results of the evaluation based only on the non-economic considerations showed the following ranking in order of favorability: Land Application Composting Heat Drying Co-Composting The results of the evaluation based only on the economic considerations again placed land application as the number one option. Table 6 shows the results of the present worth analysis conducted by WCRSA. (O Dette, 1996) Table 6: W C R S A - Present Worth Analysis for Biosolids Treatment Options. OPTION PRESENT WORTH Land Application 106 Co - Composting 143 Heat Drying 191 Composting 193 Wiedeman and Singleton, Inc. (WSI) presented at paper at the Georgia Water and Pollution Control Association Annual meeting in 1995 entitled: Cost Comparison of Biosolids Management Alternatives. The results of their studies are shown in Table 7. Table 7: Cost Comparison for Biosolids Management Alternatives. ALTERNATIVE County Landfill 357 Private Landfill 289 Dryer 201 Land Application 126 * Composting 261 Incineration 214 * Includes purchase of land application sites for US$1.7 million. It is interesting to note that at US$126 per dry ton, land application is the most cost effective option even though the costs includes US$1.7 million for the purchase of the land application sites! Normally, land is not purchased in land application projects, thus, the overall advantage of this option would be even greater in the comparison done by WSI. In their comparison evaluation, WSI showed that one of the break-even points between landfilling versus land application would come when landfill tipping fees were above US$18 per wet ton and land could purchased for US$2,000 per acre. Again, WSI 20 o Congresso Brasileiro de Engenharia Sanitária e Ambiental 4111

7 was evaluating land application with the added constraint of assuming the land would have to be purchased. (O Dette, 1996) There are not too many places in 1996 where landfill tipping fees are US$18. In fact, to meet the 40 CFR Part 258 requirements, the cost for lined landfill space is becoming very expensive. For example, the City of Chattanooga, Tennessee just completed a new 20 acre addition to their Summitt Landfill at a total cost of US$4 million, but this added capacity is estimated to be sufficient for only 1,8 years. At US$200,000 per acre construction cost much attention is going to have be given to recycling their biosolids which is currently taking up about 25% of their landfill capacity. (O Dette, 1996) Typically, land application projects in the United States will show costs of between US$50 and US$100 per dry ton. Again, with all of these reported costs one must keep in mind that there may not be a true apples-to-apples comparison. The costs for laboratory analyses and/or obtaining permits from the regulatory authorities are seldom included. Neither are the monitoring, recordkeeping and reporting requirements all of which will vary widely from state to state. Nevertheless, when one weighs all of the factors and looks at the source of the information, there is no doubt that land application of biosolids is the most cost effective option provided it is done right! One of the reasons land application will rank number one in economic evaluations that are done correctly relates to the nutrient value of the final biosolids product. Table 8 shows typical organic nitrogen concentrations in biosolids. Table 8: Typical Organic Nitrogen Concentrations in Biosolids and Biosolids Products. METHOD ORGANIC NITROGEN in PRODUCT mg / kg Land Application 40,000-60,000 R D P 25,000-31,000 Composting 20,000-24,000 Miscellaneous Alkaline 8,000-15,000 Notice that as a general rule of thumb: the higher the cost of stabilization, the lower the value of the biosolids product in terms of nitrogen. In fact, as stated previously, liquid land application of biosolids typically saves farmers US$75 to US$125 per acre in fertilizer costs! So why isn't everyone doing some form of beneficial land application? A very good question! (O Dette, 1996) CONCLUSIONS Based upon the author's experience, when land application is not being done there are two main reasons: (1) someone, using the smoke and mirrors technique, has convinced the decision makers that their current landfill or incineration option is the cheapest and/or (2) local officials are afraid of public perception and may have been sold a bill of goods by a vendor or consultant that they have to produce a biosolids product that can be bagged or given away without constraints. A Biosolids Product (BP) is defined as a biosolids that 20 o Congresso Brasileiro de Engenharia Sanitária e Ambiental 4112

8 meets all of the following three criteria: (1) the pollutant concentration values in Tables 1 and 3 of 40 CFR Part , (2) one of the six Class A pathogen reduction alternatives in (a), and (3) one of the vector attraction reduction options in (b)(1) through (b)(8). When changes are made away from landfilling or incineration, the latter group looks for alternatives that will produce a BP. However, what these people are forgetting is that the point made by the WEF Position Paper that all biosolids programs which are managed in accordance with all applicable requirements set forth in 40 CFR Part are safe. (WEF, 1996) Such programs are protective of public health and the environment; a point which has been made many times by people like Dr. Alan Rubin and Bob Southworth, the principal authors and technical experts for the 503 regulation. Dr. Terry Logan of Ohio State University, a Co-Chair of the 503 Peer Review Committee (Cooperative State Research Service Technical Committee W-170) has said: We can argue about which approach to protecting human health and the environment is more effective: processing and industrial pretreatment (EQ) or biosolids management (Class B, or non-table 3 metals), but we should support the 503 philosophy that says that both approaches are equally safe. (O Dette, 1996) The author believes that the marketplace will ultimately determine what biosolids management option is chosen. Certainly, politics, costs and public acceptance will all be factors. However, elected officials, the decision makers for how the public funds are to be spent have an ethical and moral obligation to be honest and objective in their evaluations. Therefore, as some food for thought: shouldn t these questions always be asked: Why not go with land application if it has been proven to be the most cost effective option? Why do we need to spend more money to produce a BP or even go to Class A for pathogen reduction if each option that meets the applicable requirements of 503 is safe? Unless you can develop a very lucrative market for your BP stick with land application. It is imperative to thoroughly evaluate your markets before you spend the extra money to produce a BP. Also, never forget Murphy s Law. It is hard to make donuts consistently the same 365 days a year, so it stands to reason that it is a least equally as hard to make a BP or just achieve Class A for pathogens on a daily basis. Human error, mechanical problems, poor mixing, etc. can all lead to liability problems when you are telling your customer that you are BP or just Class A. If you fail to meet the applicable 503 criteria with BP or Class A there is no fail safe protection for the customer. However, with a liquid Class B biosolids, if a problem occurs you have Mother Nature as your fail safe back-up because of the site restrictions. This point was exemplified during one of the WEF 503 Implementation Short Courses when Bob Southworth was asked a question about the New York City (NYC) biosolids that were going by train to the Sierra Blanca Ranch in West Texas. The person said that the biosolids were treated by a PSRP (Class B) before leaving NYC, but when the train arrived in West Texas the fecal coliform levels in the biosolids were over 60 million. Bob Southworth was asked if he was concerned about the fecal coliform level and his answer was no! First of all, if the biosolids were PSRP they meet the pathogen requirements in 503. Secondly, the 2 million fecal coliform number in the 503 rule is a technology number, not a risk-based number. Lastly, the site restrictions at the Sierra Blanca Ranch adequately protect the public health and the environment. The bottom line is that with any option, the treatment, use or disposal of the biosolids must be done right. This is true for biosolids recycling projects, not only in the United 20 o Congresso Brasileiro de Engenharia Sanitária e Ambiental 4113

9 States, but in every corner of the world. Liabilities and the ramifications of negative public perception will be there for any project that is not handled and performed correctly. This is one of the reasons why WEF is working so hard through its Residuals and Biosolids Committee to achieve the goal of Biosolids 2000 which is to make biosolids recycling publicly acceptable around the globe by the year BIBLIOGRAPHIC REFERENCES 1. U.S. Environmental Protection Agency (EPA) (1985), EPA Handbook: Estimating Sludge Management Costs. Washington, D.C CFR Part 503 (1990), National Sewage Sludge Survey; Availability of Information and Data, and Anticipated Impacts on Proposed Regulations; Proposed Rule; Federal Register, Friday, November 9, CFR Part 257 et al.(1993), Standards for the Use or Disposal of Sewage Sludge; Final Rules; Federal Register, Friday, February 19, U.S. Environmental Protection Agency (EPA), EPA Handbook: Improving POTW Performance Using the Composite Correction Program Approach. Washington, D.C. (October 1984). 5. A Global Atlas of Wastewater Sludge and Biosolids Use and Disposal, Edited by Dr. Peter Matthews, International Association on Water Quality (IAWQ), Scientific and Technical Report No. 4 (IAWQ, 1996). 6. O DETTE, ROBERT G., Determining the Most Cost Effective Option for Biosolids and Residuals Management, Proceeding 10th Annual Residuals and Biosolids Management Conference: 10 Years of Progress and a Look Towards the Future, Water Environment Federation Specialty Conference, Denver, Colorado, USA (August 18-21, 1996). 7. Water Environment Federation (WEF), Guidance for Regulatory Officials on Biosolids Recycling, WEF Position Statement (Approved by the WEF Executive Committee on January 25, 1996). 20 o Congresso Brasileiro de Engenharia Sanitária e Ambiental 4114

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