Session Chairs: Thomas G Sprehe, KCI Technologies, Inc; John Kellett, Clearwater Mills, LLC 

 An international panel of experts is proposed to highlight an “engineering approach” to addressing the risk and urgency of the problem, disrupting the paradigm, source control, scope, scale, cost, and timeline of interception projects, and performance measurement.

Given the relatively short timeframe during which humans have polluted the Earth with durable plastic, say +/1- 60 years, the accelerating loading rates worldwide should sound loud bells of alarm. As we become aware of the mounting evidence that bioaccumulation of microplastics often tainted with toxic waste, is already widespread in our oceanic food chain, the implications for a growing population dependent on a vibrant ocean ecosystem are horrendous. Solid waste professionals have just woken up to the fact that a gap in sanitation practices since the beginning of the plastic economy has in a short time had a significant negative global effect. Complex as the issue of marine debris waste management may be, by using the standard engineering problem solving approach the problem must be systematically addressed evaluating risk, urgency, applicable metrics, efficient design with life cycle optimization, contract delivery and financing models, and long-term performance management. Stakeholder engagement and support increases dramatically when the right engineering solutions are successfully presented.

Tom Sprehe and John Kellett have evaluated dozens of locations worldwide for implementation of river borne trash interception controls, in particular the patented Waterwheel-powered Trash Interceptor (Trash Wheel) first developed in Baltimore, MD by Kelleit. By deploying this and similar technology, the opportunity for immediate and effective triage of the sources of discharge to the oceans is huge, may be relatively inexpensive, provide meaningful employment, using sustainable energy. Other similar technologies exist at smaller scales. In all cases the relatively simple equipment may be easily removed and re-purposed as upland sources are eventually better managed or other developments may require it.

The session is intended to be coordinated with the other session related to Marine Debris Diagnostic and Restoration Planning, and the Business Case for Managing Marine Debris.




Implementing a Trash Diet for the Anacostia River, Washington, District of Columbia, USA

presenting: Matt Robinson (DC Department of Energy and Environment, Watershed Protection Division, United States); authors: Matt Robinson (DC Department of Energy and Environment, Watershed Protection Division, United States)

The Anacostia River is a tidal freshwater tributary to the Potomac River, one of the largest tributaries to the Chesapeake Bay. The river has a watershed approximately 176 square miles in size and flows through portions of the District of Columbia (Washington, DC) and the State of Maryland. In 2006, the District listed the Anacostia River as impaired for trash followed by the State of Maryland in 2008. The river is perennially impaired by loadings of plastic debris and other trash from stormwater runoff, combined sewer overflows, and illegal dumping. In 2010, both jurisdictions developed a total maximum daily load (TMDL) for trash for the river. This “trash diet” requires both jurisdictions to install controls to prevent or remove over 1 million pounds of trash per year. Examples include the installation of trash traps; establishment of a five cent fee on single-use plastic bags; banning the use of expanded polystyrene foam food products; and installation of large underground tunnels to capture combined sewer overflow. This presentation will include a summary of the kinds of data used to develop the TMDL, as well as other types of data that have been collected and used to inform policy decisions (e.g. establishment of a plastic bag fee). Practical considerations for the installation of various trash reduction best management practices (BMPs), and efforts to monitor progress will be presented. This work will hopefully inspire jurisdictions to adopt similar approaches to reduce the amount of trash in the nation’s waterbodies.


Basins and Booms: An Effective Model for Marine Debris Capture in the Tijuana River Watershed

presenting: Bronti Patterson (Tijuana River National Estuarine Research Reserve, United States); authors: Bronti Patterson (Tijuana River National Estuarine Research Reserve, United States)

The Tijuana River National Estuarine Research Reserve and the Tijuana River Valley comprise the largest intact coastal wetland system in Southern California, despite stressors associated with being situated on an international border between two major metropolitan areas of San Diego and Tijuana, Mexico. Since the early 1980’s, increasing volumes of debris originating in Mexico flow through the Tijuana River Valley during flood events and are discharged into the Pacific Ocean. During these flood events large quantities of this debris are deposited in alluvial wash habitat, riparian habitat, tidal channels, salt marsh habitat, and near-shore dune habitats of the Reserve. In 2005, the Goat Canyon Sediment Basin was constructed at a cost of nearly $6 million dollars, in order to capture 60,000 cubic yards annually of sediment and debris directly impacting estuarine and ocean habitats associated with the Reserve. The Sediment Basin contain two floating trash boom systems designed to capture floating debris such as plastics and foam. Through a broad partnership, the Sediment Basin and trash boom systems have effectively captured 500,000 cubic yards of debris and sediment from entering the Tijuana Estuary and Pacific Ocean. The Goat Canyon Sediment Basin serve as a potential model effort toward alternative and sustainable natural resource maintenance in both the U.S. and Mexico.


Prioritizing debris interception versus other management methods

presenting: Thomas Sprehe (KCI Technologies, United States); authors: Thomas Sprehe (KCI Technologies, United States), John Kellett (Clearwater Mills)

An extended 1.25 hr presentation will focus on the engineering elements of marine debris interception in streams and rivers. A diagnostic consideration of the main problem elements will be presented. The rationale for urgently prioritizing debris interception as opposed to other management methods, including regulatory policy (e.g., polystyrene and bag bans, etc.), increased recycling, imposing circular economy strictures such as reverse logistics, etc., is based on the relative ability of such interception to be implemented quickly versus the extended time to implement more sustainable solutions, while acceleration of the marine debris loading compounds the enormous threat to our oceans. Since the majority of solid waste marine debris originates as illegal or improper dumping or litter, and travels to the ocean via water flowing off of the land, the focus of prevention should be to efficiently intercept the waste at the most efficient points. This vector to the ocean is more prominent near urban centers, where stormwater runoff runs to streams and rivers flowing to the ocean. Non-point source litter becomes a concentrated point source at the mouth of a river, and it’s the last practical chance to intercept it. So from a triage perspective those become the arteries at which to stop the bleeding of plastic to the ocean. Next, the importance and challenges of data collection will be discussed as well as several innovative methods currently being implemented. Engineering design considerations for marine debris interception will be presented, as well as alternatives for structuring the operational responsibility, and funding of CAPEX and OPEX. The effectiveness of such measures can be easily communicated to the public in a way that encourages implementation sustainable solutions upstream.