Using sewage sludge to heat and charge batteries.
More and more people are worried about what to do with sewage sludge because of pharmaceuticals, microplastics, and chemical compounds that are bad for the environment (PAHs, furans, dioxins, NPE, LAS etc). Because it could be bad for people’s health, sludge is no longer spread on land in many places. Instead, it is burned. This makes it hard and expensive to put phosphorus back into the soil because it is locked up in the ash. Only three months out of the year can sludge be spread on land, and storing it for a long time causes a lot of GHG emissions. AquaGreen dries and pyrolyzes (heats to 650°C) the sludge, turning it into useful resources like energy and biochar with phosphorus. This solves the problems that sewage sludge causes for the environment and the climate. When biochar is used as a fertilizer, it helps the farmer get better crops and the climate by storing CO2 in the soil. It also helps people in the future grow plants by getting back phosphorus, which is on the EU’s list of critical scarce raw materials.
Positive facts about Combined steam drying and pyrolysis unit
One 350 kW unit capture and store 550.000 kg CO2-eq per year in the biochar treating the sludge from a city with 40.000 people
Recycle 80 % of the phosphorus in the sewage sludge
Biochar is recognised by UN IPCC in 2019 as one of three ways to capture and store carbon to avoid climate change
Sewage sludge volume reduced with 90 % and pyrolised sludge (biochar) is sterilised and decontaminated and odor free
Carbon storage via the biochar – 50 % of the carbon in the sewage sludge is captured in the biochar saving 1.1 kg CO2 eq per kg of biochar.
The phosphorous of the biochar is plant available to a very large degree whereas todays standard sludge incineration process is very problematic for phosphorus plant availability,
ROI for the waste water plant after 2-6 years – due to sludge handling/incineration cost savings
Avoiding cost of extracting phosphorus from the sludge after incineration – currently estimated in Germany to 300 €/ton (per ton sludge on dry matter basis)
Video about Combined steam drying and pyrolysis unit
https://www.youtube.com/embed/m_CmzdlmMz8
Combined steam drying and pyrolysis unit website : https://aquagreen.dk
