Converting waste to energy is gaining momentum, while weight and sustainability are driving factors behind wastewater solutions
Scanship’s microwave assisted pyrolysis (MAP) system, which turns waste into useful energy, is gaining traction in the cruise market.
Scanship chief commercial officer Bjorn Abraham Bache tells Passenger Ship Technology, “We have been working on MAP for many years and got the first contract two years ago for cruise ships currently being built. We are also in discussions for other newbuilds.”
Scanship’s process turns carbon-based waste – including paper, cardboard, wood, plastics and some biowaste – into syngas, which can be used to satisfy other energy demands on the ship using a dual-fuel boiler. The other by-product is bio-char, resembling BBQ char.
Microwave assisted pyrolysis benefits
Mr Bache says, “The benefits are that carbon is converted to steam via syngas, so a cruise ship can reduce the overall fuel used. We calculated that it could lead to a 2% reduction in fuel per year. Equally important, our MAP can replace polluting marine incinerators, setting a new standard for garbage handling. Approvals are underway.”
He adds, “When you start the process, the energy you get out will continue to keep the MAP system running, and the surplus energy can be exported for other purposes, like hot water generation for heating the accommodation areas.”
The other by-product of bio-char could be offloaded or even sold by the cruise line for applications such as a component of fertiliser for farmland and as a raw material for the metal industry, as opposed to using fossil coal.
As well as cost-saving, Mr Bache points out the “environmental impact on the operation of the cruise ship”.
He says, “If you replace the traditional incinerator that burns garbage with our MAP system, this captures a significant amount of CO2 emissions.”
Other advantages include weight saving and operational advantages. These include a quicker start-up and shut down time.
Furthermore, incinerators cannot be used in ports because they use a combustion method. But because MAP does not use combustion but rather pyrolysis, it will be able to operate in port. Mr Bache comments, “This is a huge difference for the operator as they can convert garbage to energy 24/7 instead of waiting until leaving port.”
Mr Bache sums up “All cruise owners are looking for new technology to reduce CO2 and to be more environmentally friendly. MAP will be something they will be looking at.”
Scanship also has a new biomass conditioner, the STTP, that enhances biomass dewatering and saves energy by a thermal hydrolysis process. This has been sold to a cruise ship which will reach the market soon.
Elsewhere, Scanship’s advanced wastewater solution has recently been contracted for two retrofits being carried out by Carnival Line, for Carnival Magic and Carnival Dream.
Meanwhile, Headhunter has just delivered nine shipsets to Turkey for nine new river buses under construction at Damen Antalya for Dutch operator Waterbus.
Weight and reliability
Headhunter chief executive Mark Mellinger tells PST, “This operator was concerned about weight and reliability. Previous vessels used a vacuum toilet. The Headhunter toilet system does not need a vacuum pump and flushes with about three litres of water per flush and like a vacuum toilet system, ours can be installed with small-diameter piping. Our solution was selected to meet reliability expectations, save weight and save money.”
The Tidal Wave Smart Bio system is USCG-certified according to the effluent requirements of MEPC.227(64) including section 4.2 for passenger vessels in special areas.
The company offers single systems from 1-20 m3 per day and larger systems can be organised with multiple treatment tanks. “These systems are currently working their way into the engineering on new platforms and boutique resorts where there’s a focus on sustainability and willingness to make the effort to produce reusable water,” says Mr Mellinger.
Regarding the HMX system, Headhunter has just introduced a smaller version for private yachts with a capacity of ~1 m3 per day. “This is a very compact system designed to treat wastewater in accordance with the United States Clean Water Act, described in 33CFR for private yachts over 19 m,” says Mr Mellinger.
In January 2021, Wärtsilä announced it had signed a framework agreement with Carnival Corp covering the supply and installation of its advanced wastewater and dry waste treatment systems for up to 32 vessels across many of its operating brands.
Wärtsilä’s membrane bioreactor waste water treatment plants handle black and grey waste water and the company says the system surpasses the most demanding standards set by IMO for sewage discharge, including paragraph 4.2 of MEPC 227 (64), which applies to special areas.
The company’s dry waste handling system complies with IMO Marpol requirements, and is designed to minimise greenhouse gas emissions. Wärtsilä’s advanced technologies and vast experience were cited as being major considerations in the award of this contract.
“There is increased awareness within the cruise industry of environmental sustainability, and Wärtsilä is proud and ready to support this focus with the most advanced and compliant solutions. We continue to work with Carnival Corp to enhance their goals for waste reduction, in line with their internal strategy,” says Wärtsilä water and waste’s director Arto Lehtinen.
Carnival Corp senior vice president, global strategic sourcing Jon McKeown says, “We very much appreciate Wärtsilä’s support and its capabilities in delivering high-quality, reliable solutions tailored to our specific requirements. The environmental legislation barrier for the cruise industry is set very high, so we seek the latest technologies to ensure compliance.”
The equipment will be delivered and installed on board different ships across Carnival’s brands between 2020 and 2025.
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