Eutrophication and climate change are major global problems. The sea weed Laminaria digitata and the reed Phragmites australis have the potential to absorb nutrients and CO₂ during growth, as well as being a source of renewable energy in the form of biogas. The aim of this study was to evaluate Laminaria digitata and Phragmites australis concerning biogas production and nutrient recycling using a two-stage pilot scale process. The plant has a total volume of 430 L and consists of a hydrolysis bed and an up-flow anaerobic sludge blanket reactor (UASB). Two experiments were performed; one with Laminaria digitata as the sole substrate and one with a mixture of Laminaria digitata and Phragmites australis. Frozen substrates were placed in the hydrolysis bed and digestion was performed at 305 K during 70 days for Laminaria digitata and 100 days for the mixture of Laminaria digitata and Phragmites australis. The methane yield achieved was approximately 170 L kg⁻¹ volatile substances (273.15 K, 101.3 kPa) in both experiments. These results suggest that Laminaria digitata can be efficiently digested in larger scale and has the potential to contribute to a future sustainable energy mix, considering its relatively high methane yield when anaerobically digested as the sole substrate. Digestion of Phragmites australis needs further development to make use of its full potential.

富营养化和气候变化是主要的全球性问题。海杂草海带和芦苇芦苇具有生长过程中吸收养分和CO ₂的潜力，并且可以以沼气的形式作为可再生能源的来源。这项研究的目的是使用两个阶段的中试规模过程，评估关于沼气生产和养分循环利用的指状海带和芦苇。该工厂的总容积为430 L，由水解床和上流式厌氧污泥床反应器（UASB）组成。进行了两个实验。一种以海带指作为唯一底物，另一种以海带指和芦苇。冷冻基板放置在水解床和在305ķ期间70天用于进行消化掌状海带和100天的混合物掌状海带和芦苇。在两个实验中，获得的甲烷产量约为170 L kg ^-1挥发性物质（273.15 K，101.3 kPa）。这些结果表明，掌状可以在更大的范围内有效地消化，有利于未来的可持续能源结构，考虑到其相对较高的甲烷产量时，厌氧消化作为单一基质的潜力。芦苇消化 需要进一步开发以充分利用其潜力。