A glance behind and a look ahead: history and future of a regional biosolids authority

Separated only by 3 miles and located in western Michigan, the Cities of Grand Rapids and Wyoming collectively provide wastewater treatment for approximately 400,000 people. Each municipality independently collects and treats wastewater from its own community as well as several outlying communities. Each community discharges treated wastewater into the Grand River which eventually discharges into Lake Michigan.

Prior to the formation of the GVRBA, the Grand Rapids WWTP co-settled waste activated sludge from secondary clarifiers with primary solids in the primary settling basins. Solids were then pumped to storage tanks prior to being dewatered and landfilled. This dewatering and landfill disposition route was managed by an outside contractor. At the Wyoming CWP, primary solids were mixed with thickened waste activated solids, lime stabilized, stored, and land applied. Belt presses were used as a backup measure in the event storage space became an issue. A contract operator was also used to oversee the land application program.

As part of a 1995 Facilities Plan, staff from the City of Wyoming CWP conducted an evaluation of their biosolids program. The City of Grand Rapids, in 2001, also conducted an evaluation of their biosolids program as part of their Comprehensive Master Plan. During this process, key leaders from both Grand Rapids and Wyoming met to discuss their respective biosolids futures and thought that an investigation into a joint effort would be prudent.

Throughout 2002 and early 2003, a Project Team of individuals from utility management, city management, and operations met to discuss what a collaborative biosolids management effort would look like. Black & Veatch (B&V) was hired to provide assistance in identifying biosolids processing/disposition issues as well as to evaluate varying proposals and assist in project concept formation.

The initial issues identified that supported a project included:

• Public Acceptance of Class B Biosolids. Although illegal in Michigan, a nearby township had enacted an ordinance banning biosolids application, and the threat of increasing public opposition could lead to widespread distrust and additional bans.

• Regulatory Uncertainty/Future Regulatory Climate. Although no pending changes in existing biosolids regulations were identified, there was (at that time) movement to force more restrictive standards on biosolids recycling, specifically to Class A levels.

• Existing Program Costs. Both facilities’ programs were subject to economic and other influences beyond the control of both communities. Specifically, contract term limits and urban sprawl were contributing to escalating costs. Additionally, existing equipment was aged and in need of either significant maintenance or outright replacement.

• Existing Treatment Capacity. Existing biosolids processing infrastructure was limited in capacity, and not suitable for processing future increases in solids production.

• Planned Expansions at the Grand Rapids WWTP. The City of Grand Rapids, as part of its Comprehensive Master Plan, realized that capacity expansion was necessary in order to provide the necessary level of service.

• Sustainability. Staff recognized that reducing dependence on fossil fuels as well as better use of the final biosolids material was appropriate. Additionally, increased opportunities for reuse were identified as a goal.

As a result of the issue identification, the Project Team developed the following goals and objectives as part of a proposed project:

• Address increasing public perception issues with Class B land application.

• Position the Cities, via an Authority, for Class A/Exceptional Quality biosolids production in the future.

• Position the Cities, via an Authority, for flexibility in biosolids disposal/reuse outlets, both in the short and long-terms.

• Foster cost stabilization and predictability by reducing dependence on and exposure to economic factors beyond the control of the Cities.

• Promote sustainability in biosolids reuse.

• Address existing equipment and facility age, capacity, and conditions issues at each treatment facility.

• Coordinate relocation of solids processing facilities at the Grand Rapids WWTP to allow for planned expansion of the liquid treatment process.

• Promote regional cooperation, and take advantage of economies of scale that may be afforded by a regional approach.

• Ensure regulatory compliance.

• Minimize user cost impacts.

These aforementioned goals and objectives were formally written in a Memorandum of Agreement (MOA) that was signed by both communities on Earth Day, April 22, 2003. The MOA also included a conceptual project that was designed to address the identified issues and goals. The conceptual project included: a pipeline and pumping system designed to transfer thickened solids between the WWTP and CWP in either direction; a receiving tank and anaerobic digestion facilities located at the Grand Rapids WWTP to receive, blend and process combined thickened residual solids from both facilities; installation of mechanical dewatering at the Grand Rapids WWTP to receive and dewater digested solids; installation of a heat drying facility to receive dewatered solids and process into a dried pellet product.

From 2003 to 2005, the Project Team worked with B&V to vet the conceptual project and fully evaluate alternatives. On Earth Day, 2004, the Articles of Incorporation forming the Grand Valley Regional Biosolids Authority (GVRBA) were officially signed by each community, with the initial vision of a complete system of digestion, dewatering, heat drying, and pelletizing to form a Class ‘A’ product. This became known as the ‘full vision’.

An evaluation was conducted to determine if the regional approach was financially more beneficial than each individual community pursuing similar projects on their own sites. As the table below indicates, the results of this evaluation indicated that a regional project was economically beneficial.

As is noted in Table 1, the total cost for the full vision was estimated to be $112,539,000. The proposed dry ton rate was $568, significantly more than the ∼$200 each community was currently paying. Due to this significant expense increase, the Project Team was challenged to find a way to reduce project costs/scope and find an economical way to move toward a project in a phased manner.

Throughout 2005, the Project Team worked with B&V to evaluate process and operational alternatives that would meet project goals. Four alternatives were considered, ranging from the full vision to dewatering only. In the fall of 2005, the Project Team recommended that the GVRBA pursue the dewatering only alternative while maintaining flexibility for the incorporation of future technological developments. The same analysis was conducted (Table 2) to determine if the project would be more economically beneficial if it was regionally approached versus separately, with the regional project this time costing more than separate projects. Despite this, the Project Team recommended that a regional project be developed. Both communities still wanted to achieve the ‘full vision’ at some future point and this vision was considerably less expensive as a regional project. Additionally, state government at that time was linking shared revenues to regional cooperation efforts and a regional project would bolster each community's chance at receiving more state funding.

City of Wyoming CWP primary, waste activated, or thickened waste activated sludge can be mixed or independently sent to the GVRBA storage tanks via the pumping facility and pipeline. Ferric chloride can be added to the wet wells or pipeline for odor and phosphorus control. Grand Rapids WWTP primary, waste activated, thickened waste activated, or co-settled sludge is conveyed to the storage building, where it is combined with CWP solids and stored in either the primary or waste activated storage tanks. Operational flexibility allows for any combination of sludges to be sent to either storage tank. The waste activated storage tank is equipped with an aeration system to mix tank contents and prevent phosphorus release. Ferrous chloride can be added to either the primary or waste activated tank for odor and phosphorus control. Sludge from the storage tanks is pumped to a blending tank, where it is mechanically mixed and pumped to any of three centrifuges. Mannich or emulsion polymer is added to the centrifuge feed to assist in dewatering. Twin screw feeders convey the centrifuge ‘cake’ into a progressive cavity pump, which transfers the cake to two sliding frame silos. Polymer is added to the pump discharge line to prevent buildup of excess pressure. Solids stored in the silos are transported to landfills. Centrate drains to a wet well and is pumped to the head of the WWTP. Odor control is maintained by three carbon adsorption units. The dewatering facility is operated by Grand Rapids WWTP staff, while transport and final disposition is managed by outside contractors. A biosolids transfer and process flow schematic is following:

The land application program operates only from the Wyoming CWP. Solids processing is managed by CWP staff and the land application program is managed by an outside contractor. Primary solids and waste activated sludge are thickened via centrifuges, lime stabilized, and stored for disposition. The CWP has three 2-MG storage tanks that are utilized for long-term storage. Pathogen reduction and vector attraction reduction, in accordance with federal and state biosolids regulations, occurs through both lime stabilization and soil injection. Approximately 12,500 acres of local farmland are actively enrolled in the land application program, with another 14,000 acres of inactive land that can be enrolled depending upon soil conditions.

Initial project design occurred with B&V during the years 2005–2006. Project construction occurred from 2006–2009, with the GVRBA becoming fully operational in 2010. The following table exhibits the projected production and costs (estimated in 2007) as compared to actual from 2010 through 2013. Estimates at that time did not provide detail past 2013.

As Table 3 indicates, projected dry tons were significantly overestimated. This is primarily due to the economic downturn that reduced solids production. Residential growth did not occur as anticipated and industrial/manufacturing growth also failed to materialize. Additionally and in 2012, a municipal customer of the City of Wyoming decided to expand their wastewater treatment facility and stop sending their excess wastewater to the CWP, resulting in a 10% decrease in wastewater flow.

When viewed on a dry ton basis, the Operations and Maintenance (O&M) costs are very similar to what was projected. Debt service, however, was greater than projected as the total cost to build the facilities was approximately $34M, higher than the originally anticipated $25.8M. This is the primary reason why the total actual dry ton costs are significantly more than was projected. It should be noted, however, that sidestream treatment costs are not included in the O&M costs identified in Table 3. Sidestream treatment costs are determined based on actual surcharge rates paid by a typical industrial user. Table 4 below exhibits the total cost per dry ton with sidestream treatment included.

As noted above, sidestream treatment costs are significant. However, only the City of Wyoming is assessed these sidestream treatment costs and only for periods of time when the dewatering facility is processing CWP solids. Since the remaining portion of the sidestream comes from the Grand Rapids WWTP, they are not assessed a surcharge (cost) for this treatment as it is inherent to their process.

The development and continuation of the GVRBA was and is a significant undertaking. After 10 years of existence (5 of which have been operational), a number of benefits and disadvantages can be observed. Each community has realized some benefits, but each has also experienced limitations due to the partnership. Following is an overview of these from a comprehensive program perspective.

The following benefits have been realized as a result of this partnership:

• Program Diversity. Currently, CWP solids can either be landfilled or land applied. Grand Rapids WWTP solids are landfilled in one of three local landfills. In 2012–2013, a pilot composting project was started. Although this pilot project failed due to the contractor's site location and odor issues, it proved feasible and for a year offered another disposition avenue. The current infrastructure provides a good foundation for establishing a flexible and diverse biosolids management program that can easily be augmented when proved economically feasible.

• Intellectual Resource Sharing. Both the GVRBA Board of Directors and supporting committees involve personnel outside of traditional wastewater treatment operations. These include outside engineers, municipal managers, finance people, sustainability experts, and public works staff. This diverse group encourages non-traditional thinking and provides opportunity for creative and collaborative ideas.

• Financial Benefits. As has been noted, the sharing of financial resources proved more economically feasible for the full vision. Although the partial project proved slightly more economically beneficial on an individual basis, the realization that the full vision provided significant savings at a regional level outweighed individual projects. Additionally, state revenue sharing was recently distributed based (in part) on the collaborate effort between communities. The GVRBA relationship allowed for each community to receive additional revenue that they individually would not have been eligible for.

• Regional Effort. Western Michigan serves as a role model throughout the state for local governments working together to accomplish common goals. While there are at times differences, generally governments can and have worked together on a regional basis for the benefit of the greater community. Recently, another WWTP asked to enter into an agreement with the GVRBA to use the dewatering facility as an emergency option, furthering regional efforts. Biosolids from the GVRBA are transported to three local landfills to support the production of methane gas that is ultimately used for electrical production. Additionally, there are over 12,500 acres of farmland within a 40-mile radius that are used for land application purposes.

• Futuristic. Although many municipalities have agreements with adjoining communities for purposes of providing wastewater or drinking water services, very few are solely biosolids based. The GVRBA appears to be one of several within the United States. Additionally, the structure and format of the GVRBA has been used as a template for other joint efforts throughout Michigan.

• Relationship Building. The GVRBA forces staff from each community to come together and make decisions for the benefit of each community. While disagreements occur, in general the relationship between both communities has improved throughout the process.

• Cost Tracking. Because the GVRBA is a new effort, staff has the ability to identify and track specific costs and make decisions with solid information. This was not the case previously, when biosolids-specific costs were difficult to determine and often inaccurate.

While each community has realized significant advantages with the partnership, some things have become more difficult. Following are some disadvantages of the joint effort.

• Pace. The GVRBA attempts to be as transparent as possible. Budget approvals or amendments must be approved both by the Board of Directors and each community's governing body. This process can take several months depending on when meetings are scheduled. At the operational level, each community is responsible for managing their specific components of the system and associated contracts. Yet, major component decisions are made by an Operations Team that meets monthly, effectually prolonging a purchase/change that would have occurred quicker had the community been on its own.

• Politics. The City of Grand Rapids, with a population of approximately 200,000, is significantly larger than the City of Wyoming (population approximately 74,000) and is a more diverse and complex community. Each community has different political perspectives, ideas for the future, resources, and aspirations that at times conflict. While conflict can be beneficial, it can also strain the relationship.

• Financial Resource Sharing. The sharing of financial resources is both a benefit and a disadvantage. One community may have more financial capacity at times than the other, or one may hinder the other due to the financial state of their community or utilities.

• Cultural/Organizational Differences. Both members of the GVRBA have their own culture and organizational structure, no different than any other community. One community prefers a more lateral organization while the other a more traditional, top-down approach. These two methods can and do conflict. Additionally, each community has specific policies and procedures that add to the complexity of a joint arrangement.

• Operational and Process Impacts. Neither the Grand Rapids WWTP nor the Wyoming CWP were designed to handle the change in solids processing or sidestream loading resulting from the GVRBA processing. Wyoming CWP's treatment process has been able to handle the pumping strategy well, although recent data suggests some adverse BNR impact. The Grand Rapids WWTP BNR process has difficultly treating the sidestream load that occurs when processing Wyoming solids. Staff have worked to optimize the pumping strategy but the negative impact to Grand Rapids WWTP process cannot be avoided.

Prior to the formal formation of the GVRBA, the Project Team went through a visioning process and developed a series of goals and objectives. This led to the creation of the GVRBA, the completion of the project as it exists today, and development of a formal business plan (drafted in 2007). In 2013, after recognizing that several of the factors prompting the formation of the GVRBA had been addressed, staff determined that another evaluation was necessary to both update the initial business plan and determine if an expansion of the current program was warranted.

Also in 2013 a number of engineering and consulting firms began contacting the GVRBA indicating their interest in expanding the existing program. The TAG developed a Request for Qualifications (RFQ) document that asked firms to demonstrate their ability to align themselves and a potential project with the GVRBA and Vision 2020. Seven firms responded and five of these firms were moved on to the Request for Proposals (RFP) phase.

In early 2014, the TAG worked with a biosolids engineering consultant (CDM Smith) to develop the RFP. The RFP was structured as a Design, Build, Own, Operate, Finance (DBOOF) proposal. This was primarily due to the reluctance of one of the GVRBA members to take on more debt. The RFP was unique in that the specifics of the potential expansion were not defined. Proposers were encouraged to use their creativity and technical expertise to find the best outcome for the GVRBA that was aligned with Vision 2020. The RFP placed the majority of project risk on the proposer but also all the potential for capturing a financial reward. Proposers were given the opportunity to provide an alternate proposal once the primary DBOOF structure was met. Despite a large amount of initial interest, the GVRBA received only one proposal. An economic evaluation of this proposal indicated that the proposed project would significantly increase expenses over the short (ten-year) term with only minimal savings occurring for the remaining ten years.

Because only one proposal was received, the TAG prepared a Post-Bid Addendum that provided an opportunity for all firms to informally present their approach to an alternative biosolids processing program, identify known risks and how they would be shared, describe what should be changed in the RFP such that a viable project could be possible, and detail what additional information would be needed. All five firms participated and presented their ideas. All firms proposed basic anaerobic digestion, most with public financing. All firms wanted to form a partnership using qualification-based selection, requested that the GVRBA provide some sort of financial reimbursement for development costs, and indicated that the payback period ranged anywhere from 10 to 25 or more years. All firms indicated that the current operation was very efficient and there was little efficiency to be gained without significant capital investment. Thus, the GVRBA Board of Directors decided not to proceed with a project and instead asked the TAG to work with CDM Smith and focus on identifying triggers that would prompt moving ahead with a project.

The TAG is currently working with CDM Smith to use this information to develop a pro forma using basic anaerobic digestion. Costs will be extrapolated out and used to identify ‘triggers’ as to when program expansion should occur. Besides cost/financial information, staff intend to track and monitor other social or environmental factors. These include monitoring biosolids/landfill regulations, public funding/grants/subsidized loan opportunities, complaints, and technology improvements.

The GVRBA is a unique case study of a biosolids authority that has been in existence for 10 years. The Cities of Grand Rapids and Wyoming recognized that working collaboratively to resolve their individual needs would prove economically beneficial. Although the full vision of the GVRBA has yet to be fulfilled, the foundation has been laid for a biosolids processing program that has met many of the initial goals and objectives. The economic issues plaguing the United States also affected biosolids production at the GVRBA, causing a large disparity between projected and actual dry tons. Despite this, both communities remain committed to the GVRBA and continue to realize many tangible and intangible benefits of the regional approach. Although there are limitations, the GVRBA remains a cost effective means of biosolids treatment and disposition.

The Vision 2020 document that resulted from the 2013 strategic planning process has provided the GVRBA with a solid foundation for future growth opportunities. Efforts to supplement the existing processing system during 2014 indicated that the current processing methods were incredibly effective and efficient. This has caused the GVRBA to further define its processing costs, understand non-financial impacts, and incorporate the concept of sustainability into the program. The GVRBA is currently developing a Business Operating Plan which will include definitive sustainability metrics tied to Vision 2020 as well as indicators or trigger points that define when program expansion warrants a second look. While the future state of the GVRBA is not clearly defined, the foundation has been prepared to provide a biosolids processing environment that supports a regional effort in a sustainable manner.

The author would like to acknowledge the hard work and dedication of staff from both communities who have made the formation and continuation of the GVRBA possible. Additionally, the author would like to thank Myron Erickson, PE and Kim Hackbardt from the City of Wyoming, and Scott Carr, PE from CDM Smith for their valuable assistance throughout this process.