Beneficial reuse of catch basin cleanings and street sweepings
Nathan Weeks, P.E., Senior Associate and Russell Kleekamp, EIT, Engineer, Stearns & Wheler, LLC, Hyannis, Massachusetts
Introduction: An innovative solution
The Cape Cod Towns of Barnstable and Sandwich, Massachusetts, with the assistance of engineering firm Stearns & Wheler, LLC, recently developed an innovative approach for the reuse for the dirt and debris that is removed from catch basins and streets during maintenance periods. By utilizing the debris, commonly known as catch basin cleanings (CBCs) and street sweepings, as man-made berms on the Town's capped landfills, the two Towns saved tens of thousands of dollars that would normally be spent on disposal, trucking, and labor costs.
The Towns of Barnstable and Sandwich, having recently closed and capped their unlined landfills, are currently shipping their municipal solid waste (MSW) to regional disposal facilities. Historically, Barnstable and Sandwich used the CBCs and street sweepings as daily cover at their landfills, but, after the landfills were closed, were forced to seek alternate disposal methods. The only suitable location was the Town of Bourne Municipal Landfill, the last uncapped landfill on Cape Cod. However, the Bourne Landfill has a disposal fee based on the weight of CBCs and street sweepings. Along with the disposal fee costs are transportation, labor, and fuel costs of trucking the material. A recent cost analysis performed for Barnstable and Sandwich indicate that as much as $135,000 per year may be needed for disposal expenses.
The solution was to utilize the CBCs and street sweepings at each of the Town's capped landfills not as daily cover, but as man-made berms that would serve as wind, visual, or noise breaks.
Permitting: A process for success
The regulating authority over the disposal or reuse of these materials in Massachusetts is the Massachusetts Department of Environmental Protection (DEP). The DEP has determined that the only CBC-approved disposal method is in an operating landfill. For street sweepings, there are limited pre-approved reuse methods, such as roadway fill. Any other proposed reuse methods for either CBCs or street sweepings must be approved by the DEP. This approval is granted by completing and submitting a "Beneficial Use Determination" (BUD) permit application to the DEP.
The BUD permit is issued based on an approved application that explains that the proposed reuse of the material will not pose a threat to human health and that there is adequate space available at the proposed reuse location. The BUD permit is valid for five years, after which a renewal application must be submitted.
The main components of a BUD are as follows:
Quantities and Source Description
This section tells the DEP how much and from where material will be collected. Typically, this is done by gathering information from the Town's Highway Department on the number of catch basins and how often they are cleaned. (For example, the Town of Barnstable cleans all of the approximately 7,000 catch basins on an annual basis and can accumulate up to 2,300 cubic yards of material.) The purpose of the quantities and source description section is to allow the DEP to accurately assess the volume of material that will be collected over the life of the permit.
Summary of Analysis
As part of a successful determination for a BUD application, a full laboratory soil analysis must be completed on one or more soil samples from a CBC and street sweeping stockpile. The soil analysis must include analysis for the following parameters:
Based on the comparison to set standards, the DEP will determine if the CBCs and street sweepings pose a significant threat to the public.
This section describes what will happen to the CBCs and street sweepings if the proposed reuse method is declined, and typically includes the cost analysis of CBCs and street sweepings being taken to an operating landfill.
The following example (see table) illustrates how an alternative cost analysis may be set up for a BUD application. This example is for a third Cape Cod town that recently submitted an application that is being reviewed by the DEP.
When similar cost analyses were done for Sandwich and Barnstable, the total disposal fees were $15,000 and $135,000, respectively.
The benefits of reusing CBCs and street sweepings are not limited to town dollar resource savings. From the above analysis, it is estimated that the one Cape Cod town alone would be adding 1,920 cubic yards per year to the landfill. If all the towns on Cape Cod and the surrounding area reduced their deposits at the Bourne Landfill by reusing CBCs and street sweepings at their own respective sites, the Bourne Landfill would be saved this airspace for material that is better suited for landfill disposal, such as Bourne's own waste materials.
Proposed Reuse and BUD Request
The last section of the BUD application is the request for reuse. This section describes the proposed location of the reuse and provides assurance that it has the capacity to handle five years of collected material from either or both street sweepings or CBCs. As part of this section, a site plan must be included showing a plan view of the proposed reuse facility and proposed method of reuse (in the case of Barnstable and Sandwich, the location of the berms).
It is also necessary to describe any additional measures that will be taken at the site for the construction of the proposed reuse. For example, covering the berms with topsoil and seeding them will reduce the risk of contact with the CBCs or street sweepings, which will lower the human health risk as evaluated by the DEP. Further landscaping can be done on berms, which could not normally be done on landfills. (Without the berm material, normal cover over a landfill liner is not adequate to support vegetation other than grass.) Trees and other shrubs may be planted on the berms to further emphasize their purpose as a visual break.
BUD permitting highlights
Some recent highlights of the BUD program include the following:
The Towns of Barnstable and Sandwich have been successfully permitted to reuse their CBCs and street sweepings at their landfills for berm construction. These two approvals were the first of their kind in Massachusetts and, with that acceptance, several other municipalities such as Orleans, Provincetown, Edgartown, and Harwich have recently submitted permit applications for CBC and street sweeping reuse.
With an application expense that is a fraction of the disposal cost of CBC and street sweepings, the Towns of Barnstable and Sandwich have saved thousands of dollars annually with this program that not only reduces annual expenses and saves budget money, but also is user and environmentally friendly as well.
Russell Kleekamp, EIT, is an infrastructure, solid waste, and permitting specialist. Nathan Weeks, P.E., specializes in watershed management and wastewater treatment. Both work for Stearns & Wheler, LLC in their Hyannis, Massachusetts office and can be reached at (800) 229-5629.