What they would do better if they could build it again!
By David Nightingale
With the beginning of the new decade Waste Advantage Magazine is beginning a new column called “HHW Corner”. HHW (household hazardous waste) collection is not a required solid waste program in many states. Nonetheless, it often demands special attention because it represents the most toxic fraction of the municipal solid waste stream. Damage to collection and processing equipment, worker injuries, and opportunities for recycling and reuse, and other issues have all contributed to the rise of HHW collection programs even where regulatory mandates do not exist.
Over time, the scope of many HHW collection programs has expanded to include additional components such as electronics, pharmaceutical, and other wastes of increasing concern and regulation. While small in comparison to the total waste stream, HHW encompasses a special and often surprisingly complex set of safety requirements, appropriate trainings, facility design considerations, and policy issues largely unrelated to other parts of the waste stream. This new HHW Corner column will delve into these unique issues starting with a six-part series that focuses on common missteps in designing HHW collection facilities. While this first series will take us through the June 2020 issue, feel free to contact me regarding suggestions for topics that you may like to see covered in the second half of 2020 and beyond.
HHW Facility Design Features
This is the first of a six-part short series devoted to improving the state of practice for the design of HHW collection facilities. Four decades ago, the term household hazardous waste (HHW) was coined by David Galvin with King County Metro, WA, but there was no such thing as an HHW collection facility. Now with many hundreds of permanent purpose-built HHW collection facilities across North America, it is a good time to see what trends have emerged and what we can do better as the evolution of these facilities continues. I have selected six features that are often not properly considered or well implemented. These features have significant impacts in the design or operation of HHW collection facilities due to their effects on the capital cost, operating efficiency, safety or other important characteristics. Ultimately, if you miss or are unaware of these features, you are likely to end up with an average instead of excellent performing HHW collection facility. I will start with a short retrospective discussion including the historic HHW design context before describing the first of the six most forgotten features at HHW collection facilities.
Landfill and transfer station designs have been evolving for many decades. First, due to public health and environmental concerns and more recently because of regionalization of solid waste disposal systems and state regulatory advances. A late comer to the system of MSW management infrastructure pieces are facilities specifically designed to manage HHW. Just as landfills and transfer stations have evolved, so have HHW collection facilities. When I started assisting communities in development of their HHW collection programs there were very few HHW collection facilities anywhere in North America. By the mid-1980s there were probably less than 20 such permanent collection facilities.
Some of the earliest HHW collection facilities were simply a garden shed or shipping container purchased to provide a place to store HHW out of the weather awaiting a hazardous waste clean-up contractor to package and haul it away. At that time, there were no standards or regulations focused on HHW collection facilities. Even now, state regulations that mention HHW facilities commonly lump them in with solid waste transfer stations without any specific requirements relating to the very different design and operation needs of HHW facilities. Where HHW-specific facility regulations exist, they typically focus only on the design elements that enhance worker and environmental protection without addressing cost-effectiveness or operational efficiency. So, meeting your regulatory obligations may have little to do with creating an efficient HHW operation.
HHW Facility Design Context
Although your waste permitting authority may lump HHW facilities in with transfer stations, the nature of the operations have few similarities. Transfer stations handle materials in bulk, mostly by machines, whereas at an HHW facility every item is manually handled and evaluated for its hazard and packaged or processed individually. HHW is the most toxic and dangerous fraction of MSW, so this more intensive and cautionary handling is warranted.
A worker trained only for typical transfer station operations would be unsafe without additional specialized HHW training including courses such as the HHW-specific 24-hour HAZWOPER courses offered by both SWANA and the North American Hazardous Materials Management Association (NAHMMA). Similarly, having experience with transfer station design is not a sufficient background to design an HHW facility. However, in the early days no one had HHW design experience. Consequently, many HHW facility design mistakes and missteps unknowingly occurred and have been perpetuated in subsequent facility designs. Eventually, we learn from our mistakes. This HHW Corner series is meant to help HHW managers and design professions learn from our common historic mistakes quicker.
Naturally, in the past 30 plus years, the design of HHW collection facilities have evolved. In my experience, visiting 148 HHW collection facilities in 27 states and three provinces, I have found a number of key opportunities for better HHW collection facility design that are often missed during the design process. Many times, they are missed because of a lack of understanding some basic concepts of HHW operations and design. Other times budget constraints forced the elimination of a key feature. Regretfully, only after the facility is built do the significance of these shortcomings or missteps become painfully evident.
Forgotten Feature #1: Smaller Is Not Better
One trend has been the creation of larger HHW collection facilities. The garden shed of perhaps 100 square feet employed by a number of pioneering programs is not even considered as a legitimate option today. However, in touching bases with managers of HHW collection facilities over many years, only in recent years have I heard the report that after the first year of operations any HHW facility was built large enough. What looks great on paper often does not translate well to the real world. Compounding this historically too small facility design path is that HHW programs are often required to collect an expanding list of materials. It is now common for HHW facilities to accept high-volume electronics, white-goods, and other hard to handle large volume wastes that are not part of the traditional HHW menu. Product stewardship programs, which remove electronics, paints, and other covered materials from HHW facilities without charge, are a huge help in defraying facility operating costs. However, managing large volumes of new waste streams only compound the problem of the majority of facilities which were originally built too small.
Just like a solid waste transfer station, a too crowded HHW collection facility creates process and materials handling inefficiencies and decreases overall operating safety. Many pioneering local jurisdictions have evolved to develop successive HHW facilities—some now operate out of their second generation, and in a few cases, their third generation, HHW facility. Of course, these next generation facilities are always designed larger than their predecessors.
One Size Does Not Fit all
HHW collection programs vary widely due to differences in their service territories, goals and policy/legal drivers. The choices of what wastes to accept and what to process before shipping offsite can make significant differences in the design of an optimum HHW facility. One size does not fit all situations. The elephant in the room is how big should I make my facility so that it does not suffer from inefficiency (time and money) and less safe operations? Good facility design cannot assure perfectly safe operations under all conditions, but a bad design can create additional hazards and increase operating costs.
For HHW collection facilities there is an operating efficiency threshold that is represented by how much can be placed on a semi-truck. Even at relatively modest size jurisdictions, it is possible to ship out multiple semi-truck loads per year and realize transportation operating cost savings. For low population areas the capital cost of a facility large enough to ship in semi-truck quantities may not be justified.
In addition to the space needed to process and store HHW, there is also a need to provide space for functions that support waste management. HHW facility supporting functions often include office area, restrooms/changing areas, reuse area and storage areas for supplies of drums, boxes, personal protection equipment, and mechanical and electrical spaces. HHW management areas include customer receiving (under cover), sorting, processing and storage areas. Cumulatively, the supporting functions are a significant proportion of the facility size and are not always fully considered in the design process.
One way to increase the efficiency of the available space is to use vertical storage for supplies and some types of waste storage. This allows more materials to be managed in a smaller facility footprint. This can be accomplished using mezzanine levels in the building, pallet rack systems or a combination. However, this can lead to a need for upgraded fire protection system costs if combustible or flammable materials are stacked too high. For this reason, drums of flammable liquids are usually stored unstacked. On the other hand, pallets of empty drums and absorbents are usually good candidates for the use of pallet racks.
Facility Size Estimates
Ultimately, facility sponsors want to know “What size does my HHW collection facility need to be?” Of course, the answer is project specific and depends on the operating assumptions, site constraints and many other factors. Nonetheless, based on some recent facility designs, I have made some approximate minimum facility size estimates. One key consideration is service area population. As mentioned above, some smaller populations may not be able to justify the capital cost of a facility capable of shipping semi-truck volumes of HHW (see Figure 1).
The second column of Figure 1 suggests some minimal building sizes considering the population in the service territory, and assuming management of only the traditional HHW materials (no space allocated for electronics, white goods, or other expanded scope of accepted materials), appropriate use of vertical storage, minimum supporting functions, a small covered receiving area and efficient materials flow patterns. The minimal size for your facility may actually be larger based on the anticipated operating model, waste types accepted and materials handling processes. For facilities serving populations of less than 50,000, it is assumed that shipments of HHW are in large box van trucks instead of semi-trucks. Because these minimal sizes are highly constrained, I suggest that for planning purposes that a much better starting point for a new facility be assumed to be 50 percent to 100 percent larger. This planning level building size is shown in the last column and reflects a range of facilities of recent vintage that appear to be sufficiently large for a variety of operating conditions. The planning level building size often allows some level of future growth, some waste streams beyond the traditional HHW list, a good-sized reuse area (more on that later in this series) and flexibility for longer-term efficient operations.
Room for Expansion
One final suggestion for any HHW facility design is to provide for the future option to conveniently expand through at least one side of the building. Based on history, you are likely to need it going forward. | WA
Next month’s Part 2 topic will focus on why most facilities have inadequate ventilation and a short dive into the building and mechanical code ventilation requirements.
David Nightingale, CHMM, S.C., is Principal at Special Waste Associates (Olympia, WA), a company that assists communities in developing or improving HHW and VSQG collection infrastructure and operations. They have visited more than 140 operating HHW collection facilities in North America. As a specialty consulting firm, Special Waste Associates works directly for program sponsors from project concept through final design review; staff is often with project programming, which documents the objectives and unique context for your project before the detailed design process begins. They provide independent design review for new or upgrading facilities—from concept through final drawings to create safer, more efficient, and cost-effective collection infrastructures. System analyses of existing collection systems can provide practical paths to increase participation, reduced unit costs, increase operational efficiencies and create a more balanced program. Special Waste Associates also provides HHW health and safety training and has published the book HHW Collection Facility Design Guide. David can be reached at (360) 491-2190, e-mail email@example.com or visit www.specialwasteassoc.com.