Evaluation of Innovative and Effective Trash Capture Technologies in Urban Southern California

Purpose Despite the installation of full capture trash systems, trash still remains a visible pollutant on Southern California beaches. This presentation highlights the various trash capture systems implemented throughout the region and demonstrates the importance of selecting the right kind of system for each area. Every year, millions of tons of plastic enter our rivers and oceans. Some estimate that there are over 170 trillion plastic particles in the ocean weighing over 3.5 million kilograms, and rapidly increasing since 2005. If no action is taken, plastic will increasingly impact our ecosystems, health, and economies. Here in Southern California, locals and tourists alike take pride in the easily accessible beaches along the coast. Trash discharge accumulates near the beach and becomes a public nuisance, creates harmful environmental impacts, and increases the cost associated with cleanup. The Ocean Cleanup estimates that marine plastic costs the US 290 million dollars in costs associated with impacts to fisheries, government clean up, and reduced tourism activities. While municipalities often have solid waste management programs, around 80% of the trash pollution that ends up in the ocean originates from land. This debris comes from a variety of sources such as littering and extreme weather events, and often ends up in rivers or storm drains that outlet to the ocean. Southern California has a combination of natural rivers and stormwater channels, which both convey storm flows from inland regions towards the ocean. With those flows is an increasing amount of trash and debris. Stantec has evaluated and installed various Regional Trash Capture Technologies, such as the Ocean Cleanup's Trash Interceptor in Los Angeles' Ballona Creek and the Trash Wheel in Orange County's Newport Bay. The deployment of these trash capture systems could be replicated in other waterways where trash remains an issue, and the evaluation methods, environmental considerations, and benefits will be important to consider for each unique situation. Environmental Considerations Installing a trash capture device requires extensive consideration of potential environmental impacts. The existing waterways must be well understood from a hydrologic perspective as well as an ecologic understanding. The river can change from riverine flows to intertidal zones near the ocean, and ecology can vary from the riverbank to the riparian zones to the clearwater in the middle of the river. Various flora and fauna can be affected by any changes made to the waterway, and the potential of effects of a trash capture device should be evaluated early on, such as: -Physical encroachment on existing habitats - Noise, light, thermal, or odor pollution -Vector control -Water quality effects -Changes in flows A variety of regulations and permitting may also need to be considered. In California, relevant agencies included the Coastal Commission, Regional Water Quality Control Boards, California Department of Fish and Wildlife, US Department of Fish and Wildlife. For the two case studies, both were located near protected environmental areas. Ballona Wetlands Ecological Reserve is located upstream and along the banks of the Ballona Creek in which the Trash Interceptor is stationed. The Newport Trash Wheel is located just upstream of the Upper Newport Bay Nature Preserve. Reducing trash in close proximity to protected natural areas has clear environmental benefits, but there were also considerations made to ensure the impact of the capture devices to the protected areas were minimal. System Evaluation Existing Conditions To evaluate what trash capture system a site should deploy, an analysis of the location's hydrologic and hydraulic conditions should be conducted. This would take into consideration local factors, such as precipitation, runoff, tidal influences, land use types, expected flow rates, and watershed analyses, depending on the location of the intended trash solution. Different categories of land use correlate to different predicted amounts and types of trash and debris. Trash Capture Types A variety of trash capture devices exist and should be deployed depending on site conditions. These include in-line screens, nets, underground hydrodynamic separators, floating trash collectors, among others. For smaller flow applications, such as in tributaries, in line screens or nets may be the more cost-effective method to collect trash before flowing to a main waterway. Trash collectors are logical for a wide waterway where the collector has space to intercept trash flowing downstream using trash booms or arms during storm events. The site also needs space for emptying the trash bins aboard the collector. Where there is less real estate available on the surface of the water, screens or underground installations may be better suited. For example, both the Newport Trash Wheel and the Ballona Creek Interceptor have surface water available for a floating collector, as well as nearby areas where the collector can be 'docked' to facilitate emptying the containers on the collector itself. Benefits Aside from feasibility, it's prudent to understand the cost-benefit ratio of implementation The device is meant to alleviate costs, not further burden municipalities, and an analysis should be done to ensure that the unmanned devices, with minimal maintenance needs, are more cost efficient than solely relying on the intense maintenance of manually removal. When comparing trash capture systems, removal efficiency may also play a factor in system selection. Funding could also be leveraged by businesses interested in contributing to off-setting their trash contributions; for example, a food and beverage company contributed funds to the Ballona Creek Interceptor project. For more visible trash capture systems, community input will also be a key factor, as there may be impacts to recreational activities, or just the aesthetic of a permanent, visible solution. At times, having a visible trash capture device publicly demonstrates how progress is being made towards reducing trash on beaches and harbors, and can act as an educational opportunity in addition to its reduction of pollution. Conclusion Trash will continue to be an issue on the coastlines until more is done to reduce the volume of trash being produced. These innovative and effective trash capture technologies should be considered temporary solutions to solve an issue fueled by the current culture of overconsumption and plastic use. Until those habits are challenged and changed, trash capture devices will be an effective way to reduce the amount of trash flowing into the ocean. As various jurisdictions work towards policy changes towards a more sustainable future, these trash capture devices are a unique solution that can be implemented on the regional scale now. The combined effects of these distributed solutions can lessen the global damage of trash pollution. Status The projects shown in the case studies are completed, and another evaluation is underway. The Ballona Creek Interceptor is currently deployed. The Newport Trash Wheel is expected to be complete this year.