\u201cThere are a lot of good ideas out there, but you need practical experience,\u201d says B\u00e5rd Haug of SpillTech, a company that\u2019s turning from oil incident mitigation to trash clean up. If a system is going to be sitting out there for extended periods, there are the various stressors of current, wind and waves \u201cand you also want to know what happens to your technology when it\u2019s exposed to UV and saltwater\u201d he points out.<\/p>\n
A couple of companies have hit on practical \u2018bin\u2019 solutions. The Portbin has been designed for those nasty patches that keep turning up in sheltered corners. It sits neatly with just an upper hoop showing on the waterline and moves with the tide, an impeller drawing the flotsam into the collecting basket below. It also presents fairly a low entry bar for investment: you\u2019ll probably get change from US$10,000 on the standard model.<\/p>\n
In a similar fashion, the Seabin relies on a water pump to suck the floating trash into a mesh bag. Founder Pete Ceglinski says that cigarette butts, packaging and \u2013 tellingly \u2013 microplastic particles are the most common items caught but larger items, including a banana tree and an office chair, have been found trapped by the inflow. Interestingly, Seabin is involved in a reverse crossover, it is to start mopping up small patches of oil using an inexpensive absorbing pad.<\/p>\n
Although these are fairly economical, low-power units, they will likely require a straightforward electrical connection. Solar panels might seem an obvious pairing but Haug explains that the PortBin\u2019s 900W draw would probably demand a sizeable photovoltaic installation.<\/p>\n
Therefore, SpillTech is also looking at a passive device for off-grid deployment. Again, this takes advantage of local conditions \u2013 instead of reaching across the whole breadth of the fairway, a boom is positioned so that the current shunts the greater part of the flotsam along to the basket.<\/p>\n
However, while the smaller \u2018bin\u2019 designs can be emptied by hand, the XL sizes will likely need a crane or winch. This is an often underappreciated detail: although the volume of material may not account for much, \u201cif bottles or containers are partly filled with water, or there are a lot of autumn leaves, the weight in a 1,000-litre basket can reach half a tonne\u201d, explains Haug.<\/p>\n
The TRASH system, developed by New Naval Ltd (another oil spill crossover), goes some way to answering the issue. This combines channelling booms with subsurface skirts, directing the garbage to a multi-tiered, removable steel mesh collection cage sitting on a floating base.<\/p>\n
Efficient, low-power onboard pumps switch layers as they fill \u201cbut it also gives the top storage levels a chance to evaporate or drain off some of the water before collection\u201d, explains designer Alexandros Panagopoulos, adding that the prototype cage can be lifted off and tilted which further lightens the load \u201cassisting the recycling company with the final processing\u201d.<\/p>\n
Testing in Piraeus<\/strong><\/p>\n The full scale model, tested in Piraeus last year, features a 6m long, 3m wide and 4.7m high three-level cage capable of holding nearly 900kg of rubbish before emptying by truck or barge-mounted crane.<\/p>\n However, it\u2019s both scalable and configurable for the location: for example, adding an impeller could increase flow into the cage. Further, the Piraeus prototype ran from batteries paired with solar panels \u201cbut you could also use wind or wave power for other off-grid installations\u201d says Panagopoulos. Interestingly, remote online video monitoring, information and activation can take place by PC or even smartphone app.<\/p>\n There is another, even larger solution for plastic-heavy waterways. The Interceptor, developed by the Ocean Cleanup team, still relies on a current to shift the trash along a collection boom to the collection vessel. But at this point the process becomes very high tech: a permeable conveyor belt lifts the flotsam upwards onto an automated shuttle which distributes the waste into bins sitting on a barge between the hulls. Oversized debris is taken care of by a passive deflection function, conveyor jams trigger an automatic shut down.<\/p>\n Once a filled barge is taken to a local waste management facility, the shuttle will act as a buffer, continuing the trash collection. Though designed for 24\/7 autonomous operation, the power demands can be covered by the 5.6kW photovoltaic cells paired with a 20kWh lithium-ion battery. An internet-connected onboard computer monitors the system\u2019s performance, energy usage and component health.<\/p>\n It is effective, capable of dealing with 50,000kg of trash a day \u2013 even 100,000kg under ideal conditions, claims the team. Obviously, this would require intensive discharge operations but the automatic bin filling means there is no tricky, manual loading.<\/p>\n Again, it\u2019s a step up in price. The first pilots in Jakarta, Klang, the Mekong Delta and Santa Domingo cost around US$750,000, but once it is in series production, expect the price to drop, say the Ocean Cleanup team.<\/p>\n Other trash collectors are swimming over the horizon: SpillTech, for example, has been developing a battery-driven robo-cleaner. The stable, double hull and twin thruster design has no rudder to foul – and it has enough onboard power for a normal, eight-hour shift.<\/p>\n \u201cIt has a shark\u2019s wide mouth, and behind that is a big mesh bag \u2018stomach\u2019 that can be swapped out when it\u2019s full,\u201d describes Haug, adding that the idea is to make that automatic. With a beam of just 240cm it\u2019s small enough to be transported on a jet-ski trailer: \u201cIt could be taken from place to place, hoover up the rubbish, and then be packed off for the next location,\u201d he explains, which means that it could be useful for share agreements or rental.<\/p>\n While Haug says the prototype \u201cis already out there, doing small jobs… and looking very efficient\u201d, SpillTech is looking to enlarge the 200Ah battery capacity and get it to move little faster than its present 2 to 3 knots: \u201cWe\u2019re also experimenting with a docking station design, which would automatically empty and recharge the robot cleaner at the same time,\u201d he adds.<\/p>\n The approach in Canada<\/strong><\/p>\n Some regions suffer far more than others: \u201cThere are places around ports where you cannot see the water for plastic,\u201d says Rad\u00e9 Svorcan, of Canadian developer, Technika Engineering. It is a real issue – not just for the wildlife which gets strangled or choked by it, but even for critical infrastructure such as pumping stations.\u201d<\/p>\n The problem is, if there\u2019s no current to bring the trash to you, a powered device is necessary \u2013 and ideally one able to carry on working without crew. At the same time the sheer volume of rubbish militates against the simple evolution of existing, manned sweeper designs into remote or autonomous operation. Firstly, \u201cthese have a high power demand as the vessel is working hard against drag and the volume of water trapped between the booms\u201d, explains Svorcan. Secondly, and arguably the biggest problem, \u201cis the tendency to clog\u201d.<\/p>\n Therefore, the DeltaSea device takes a completely different approach. A pair of helicoidal \u2018arms\u2019 don\u2019t fight the water or garbage, but instead continue turning their way through the floating trash: their screw action yields a steady, 1m per second pace and delivers the debris to the collection basket at the rear. Onboard is the appropriate signalling, communication and monitoring tech to operate it remotely (in busy locations) or even autonomously out in the open sea; those utilised in high traffic areas will have additional cameras – and ideally be integrated with the port\u2019s VTS.<\/p>\n It may be novel, but recent trials in Vancouver have demonstrated the DeltaSea\u2019s effectiveness: \u201cIt can cover up to 0.5km2 of water surface area during a 24-hour period,\u201d says Svorcan.<\/p>\n While the first units will run on batteries recharged at the quay, the idea is that later devices will be able to pick up solar and wave energy, yielding a longer range. Most importantly, there is also the option of adapting the craft\u2019s rear to connect with a conveyor and barge to accept larger quantities of debris prior to transfer to shore. Further, the DeltaSea isn\u2019t limited to plastics: it can also clean up oil and chemical spills in a pollution incident.<\/p>\n The initial design (with a price nominally starting around US$150,000) has 6.5m booms with an 8.5m spread which, usefully, can be altered or closed up entirely for stowage and transport. However, Svorcan adds that as it can scale up easily, other, higher-throughput sizes \u201care available\u201d.<\/p>\n","protected":false},"excerpt":{"rendered":" Waterborne plastic pollution grabs public attention – manual cleaning is, however, time-consuming and labour intensive. Stevie Knight asks if unmanned systems can help?<\/p>\n","protected":false},"author":8,"featured_media":987,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[16],"tags":[],"sponsor":[],"class_list":["post-986","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-terminal-operations"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.portstrategy.com\/coastlink\/wp-json\/wp\/v2\/posts\/986","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.portstrategy.com\/coastlink\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.portstrategy.com\/coastlink\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.portstrategy.com\/coastlink\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/www.portstrategy.com\/coastlink\/wp-json\/wp\/v2\/comments?post=986"}],"version-history":[{"count":1,"href":"https:\/\/www.portstrategy.com\/coastlink\/wp-json\/wp\/v2\/posts\/986\/revisions"}],"predecessor-version":[{"id":988,"href":"https:\/\/www.portstrategy.com\/coastlink\/wp-json\/wp\/v2\/posts\/986\/revisions\/988"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.portstrategy.com\/coastlink\/wp-json\/wp\/v2\/media\/987"}],"wp:attachment":[{"href":"https:\/\/www.portstrategy.com\/coastlink\/wp-json\/wp\/v2\/media?parent=986"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.portstrategy.com\/coastlink\/wp-json\/wp\/v2\/categories?post=986"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.portstrategy.com\/coastlink\/wp-json\/wp\/v2\/tags?post=986"},{"taxonomy":"sponsor","embeddable":true,"href":"https:\/\/www.portstrategy.com\/coastlink\/wp-json\/wp\/v2\/sponsor?post=986"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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