Litter trap technologies retrieve floating plastic debris in rivers, ports, and harbors before it can enter seas and oceans.
KEY CONSIDERATIONS: Litter trap technologies take advantage of natural forces such as water currents and wind to effectively capture plastic debris before it can reach the sea, requiring no energy to function and respecting the natural environment.
MORE INFORMATION: https://www.clearrivers.eu/
THE PROBLEM
Rivers are the main source of ocean plastic pollution. They are the arteries that carry waste from land to the ocean. To rid the oceans of plastic, we need to not only clean up what is already out there, but also stop new plastic from entering the ocean: we need to close the tap.
See: https://theoceancleanup.com/rivers/
THE SOLUTION
Litter trap technologies are cost-effective devices that stop the diffusion of plastic litter in waterways at its source, retrieving plastic from rivers, ports, harbors and canals before it enters our seas and oceans. These systems take advantage of natural forces such as water currents and wind to capture plastic, requiring no energy to function and respecting wildlife and the environment.
Litter traps are placed in the opposite direction of the water current so plastic debris is carried towards the opening of the trap by currents and winds. Once litter is trapped inside, it will not be able to escape even if the current changes direction (although there are easy escape routes for fish and other animals including birds).
Some debris entrapment systems like The Interceptor™ have the current carry captured plastic onto a conveyor belt that continuously extracts debris from the water and delivers it to a “shuttle”, which automatically distributes the debris across six dumpsters and, using sensor data, fills containers equally until they reach full capacity (50m³). When the interceptor is almost full, it automatically sends a text message to local operators to come and collect the waste. Operators then remove the barge, bring it to the side of the river, empty the dumpsters, send off the debris to local waste management facilities. The Interceptor™ is 100% solar-powered, extracts plastic autonomously, and is capable of operating in the majority of the world’s most polluting rivers.
ALTERNATIVE SOLUTIONS
The Shoreliner is a floating waste collector with canvas submerged in the water to about 50 cm. This float collects both plastic waste and micro-plastics and guides the collected waste to a collection and removal unit.
StormX engineered to capture gross pollutants and handle powerful stormwater runoff at most urban hot spots. Commercial grade, reusable nets provide full capture of gross pollutants as small as 5 mm, including organic materials (such as leaves) that could reduce the levels of phosphorous and nitrogen in our water. This economical solution to litter and debris in stormwater runoff is highly effective for “first flush.” To prevent flooding, built-in overflows allow heavy runoff to flow unimpeded.
The Great Bubble Barrier creates a barrier stopping plastics from flowing past but allowing fish and ships to pass through unimpeded. A “bubble screen” is created by pumping air through a tube with holes in it, which is located on the bottom of the waterway. The Bubble Barrier creates an upwards thrust, which brings waste to the surface of the water. By placing it diagonally in the waterway, the Bubble Barrier uses the natural current to guide the plastic to the catchment system at the riverside. Both ships and fish can pass the Bubble Barrier, but plastic will be stopped.
PumpGuard is an efficient pre-screening device that utilizes disposable mesh nets to capture solids and protect pumps, rotating equipment, disinfection systems and other machinery from potential damage by removing debris from the waste stream. PumpGuard can be designed to operate in conjunction with pump stations, between the primary and secondary clarifiers and downstream of the headwork screen.
See also the City of Sydney’s Seabin Project.
CASE STUDY EXAMPLES
Together with the Audi Environmental Foundation, CLEAR RIVERS successfully installed a Litter Trap in the harbor basin of Brussels after a positive test phase. The Litter Trap is emptied twice a week and the average amount of waste collected is 1.5 cubic meters per month.
In Rotterdam, CLEAR RIVERS developed three passive Litter Traps to efficiently retrieve the plastics from the New Meuse (Nieuwe Maas). During a trial period of 1.5 years, the Litter Traps are tested, monitored and optimized. This resulted in a successful working system.
In 2017, CLEAR RIVERS started their first project to install passive Litter Traps at river mouths and other highly polluted waters in Indonesia. Together with local organizations, they made three Litter Traps from low budget, re-used local materials.
See: https://www.clearrivers.eu/litter-traps
Mr. Trash Wheel
Mr. Trash Wheel, officially called the Inner Harbor Water Wheel, is a trash interceptor that removes trash from the Jones Falls river as it empties into the Inner Harbor in Baltimore, Maryland. Sustainably powered and built to withstand the biggest storms, Mr. Trash Wheel uses a unique blend of solar and hydro power to pull hundreds of tons of trash out of the water each year. See https://www.mrtrashwheel.com/ for more information.
