This study investigated the anaerobic digestion of an algal–bacterial biofilm grown in artificial wastewater in an Algal Turf Scrubber (ATS). The ATS system was located in a greenhouse (50°54′19ʺN, 6°24′55ʺE, Germany) and was exposed to seasonal conditions during the experiment period. The methane (CH₄) potential of untreated algal–bacterial biofilm (UAB) and thermally pretreated biofilm (PAB) using different microbial inocula was determined by anaerobic batch fermentation. Methane productivity of UAB differed significantly between microbial inocula of digested wastepaper, a mixture of manure and maize silage, anaerobic sewage sludge, and percolated green waste. UAB using sewage sludge as inoculum showed the highest methane productivity. The share of methane in biogas was dependent on inoculum. Using PAB, a strong positive impact on methane productivity was identified for the digested wastepaper (116.4%) and a mixture of manure and maize silage (107.4%) inocula. By contrast, the methane yield was significantly reduced for the digested anaerobic sewage sludge (50.6%) and percolated green waste (43.5%) inocula. To further evaluate the potential of algal–bacterial biofilm for biogas production in wastewater treatment and biogas plants in a circular bioeconomy, scale-up calculations were conducted. It was found that a 0.116 km² ATS would be required in an average municipal wastewater treatment plant which can be viewed as problematic in terms of space consumption. However, a substantial amount of energy surplus (4.7–12.5 MWh a⁻¹) can be gained through the addition of algal–bacterial biomass to the anaerobic digester of a municipal wastewater treatment plant. Wastewater treatment and subsequent energy production through algae show dominancy over conventional technologies.

Graphical abstract

中文翻译：

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藻类草坪洗涤器系统中藻类细菌生物质的厌氧消化

本研究调查了藻类草坪洗涤器 (ATS) 中人工废水中生长的藻类细菌生物膜的厌氧消化。ATS 系统位于温室内（50°54′19′N，6°24′55′E，德国），在实验期间暴露在季节性条件下。甲烷（CH ₄) 通过厌氧批量发酵确定使用不同微生物接种物的未处理藻类细菌生物膜 (UAB) 和热预处理生物膜 (PAB) 的潜力。UAB 的甲烷生产力在消化废纸的微生物接种物、粪肥和玉米青贮饲料的混合物、厌氧污水污泥和渗透的绿色废物之间存在显着差异。使用污水污泥作为接种物的 UAB 显示出最高的甲烷生产力。沼气中甲烷的比例取决于接种物。使用 PAB，经消化的废纸 (116.4%) 和粪肥和玉米青贮饲料的混合物 (107.4%) 接种物对甲烷生产力产生了强烈的积极影响。相比之下，消化的厌氧污泥（50.6%）和渗透的绿色废物（43.5%）接种物的甲烷产量显着降低。为了进一步评估藻类生物膜在循环生物经济中废水处理和沼气厂生产沼气的潜力，进行了放大计算。发现0.116公里²一般的市政污水处理厂都需要 ATS，这在空间消耗方面存在问题。然而，通过在市政污水处理厂的厌氧消化器中添加藻类细菌生物质，可以获得大量的能量盈余（4.7-12.5 MWh a ^{-1 ）。}通过藻类进行的废水处理和随后的能源生产显示出优于传统技术的优势。

图形概要