Finnish Port Turns Sewage from Cargo Ships into Biogas for Transport

(Gasum/NGV Journal) The Baltic Sea Action Group (BSAG) is bringing together cooperation parties for the new Ship/t Waste Action project that produces biogas from sewage discharged by cargo ships at ports. The cooperation promotes the circular model of turning sewage into biomethane that will be used as fuel by heavy transport. The Ship/t Waste Action develops waste value chains between different parties, and the port of HaminaKotka is the first location.

“We can achieve our objective of a cleaner Baltic Sea, one ship, one port and one country at a time. The nutrient load on the sea decreases every time wastewater is discharged at the port. We need extensive cooperation to succeed in our mission,” said Elisa Mikkolainen, Project Director at BSAG.

Kymen Vesi treats the sewage discharged by cargo ships at the port of HaminaKotka. The wastewater sludge created in the process is refined into renewable energy at Gasum’s biogas plant. Kymen Vesi also takes samples of the wastewaters discharged by ships, which generates research data on, for example, nutrient content.

“The port of HaminaKotka is the largest general port in Finland, visited by approximately 2,500 cargo ships every year. We want to encourage the ships to discharge their wastewater at the port. Our sewage reception and treatment facilities meet the requirements of the circular economy,” commented Suvi-Tuuli Lappalainen, Development Manager at the Port of HaminaKotka.

Wastewater and food waste contain, for example, nutrients, bacteria, fats, chemicals and microplastics. If wastewater and food waste are discharged into the sea, they accelerate two of the worst problems of the Baltic Sea: eutrophication and oxygen depletion. There are approximately 2,000 ships operating in the Baltic Sea every moment, and 95 % of these are cargo ships. It is legal to discharge greywater, sewage and ground food waste into the Baltic Sea.

“For us at Meriaura, sustainability starts where legislation ends. We want to be pioneers in preventing discharges from all vessels, and we hope other shipping companies will also take voluntary measures for sustainable waste recovery,” explained Mia Hytti, Sustainability Specialist at Meriaura.

Passenger ships, such as the ferries between Finland, Sweden and Estonia, have been voluntarily discharging their wastewaters at the port for years. Since 2021, the IMO regulations prohibit discharges of untreated sewage from passenger ships in the Baltic Sea. There is no similar regulation for cargo ships. READ MORE

Excerpt from American Society of Mechanical Engineers: If the rest of New York City’s 13 wastewater treatment plants were outfitted with digester eggs, they could produce an additional 26 million cubic feet daily. That theoretical daily output of all 14 wastewater treatment plants could supply 112,000 homes daily.

One would think that New York’s 9 million residents would be a financial boon, but it’s trickier than it seems. Coming out of the digesters, biogas is a mixture of methane and some “impurities”—for example, sulfur, which is a health hazard and an environmental contaminant. These impurities must be removed before it can flow into the pipelines, and that requires building a purification plant. For now, Newtown Creek burns its biogas to keep the digesters warm and the microbes alive and comfy—and flares the rest. It’s working with Con Edison on purification. READ MORE