The land-based and seawater-independent production of macroalgae as a source of renewable biomass with a multitude of potential applications increasingly attracts the attention of science and industry. However, the availability of a feasible nutrient source acceptable for supplying a large-scale cultivation facility on land remains a persisting obstacle that has not yet been overcome. Hence, this study aimed to test an uncomplicated technological approach to sufficiently reduce the nutrient load of the biogas digestate and to identify an optimal ratio of pretreated digestate to volume of cultivation medium. Based on an initial solid-liquid separation of biogas digestate, the liquid phase was treated with flocculation agent and fine separation (liquid A), followed by filtration through an organic sorption filter (liquid B) and finally through a high-performance soil filter (liquid C). The results showed notable differences regarding the nutritional value of the different process liquids. The mixtures of process liquids A to C with artificial seawater (ASW) optimal for biomass increase were 1:50, 1:10 and 1:1, respectively. Maximum biomass increase was achieved by using a mixture of process liquid A and ASW with the ratio 1:50, which resulted in a growth rate of 7.02% FW d⁻¹ in comparison to a growth rate of 5.71% FW d⁻¹ of the untreated control group that used f/2-standard nutrient supply. Regarding the attempt of using a maximum amount of digestate and of reducing the necessity of diluting the process liquid with ASW, process liquid C with a mixing ratio of 1:1 appeared promising for a large-scale land-based cultivation of marine macroalgae. However, the transfer of the data to other agricultural biogas plants needs to be adapted to the respective case as changing feeding strategies of the biogas fermenters with different biogas substrates might lead to a large variation of nutrients in the biogas digestate resulting in changing quality and quantity of nutrients in the produced process liquids.

作为可再生生物质来源的大型藻类的陆基和海水独立生产具有众多潜在应用，这越来越引起科学和工业的关注。然而，为陆上大型种植设施提供可接受的可行营养源仍然是一个长期存在的障碍，尚未克服。因此，本研究旨在测试一种简单的技术方法，以充分降低沼气消化液的营养负荷，并确定预处理消化液与培养基体积的最佳比例。基于最初的沼气消化液固液分离，将液相用絮凝剂处理并进行精细分离（液体A），然后通过有机吸附过滤器（液体B）过滤，最后通过高性能土壤过滤器（液体C）过滤。结果表明，不同工艺液体的营养价值存在显着差异。最适合生物量增加的最佳工艺液体A至C与人工海水（ASW）的混合物分别为1：50、1：10和1：1。通过使用比例为1:50的处理液A和ASW的混合物实现最大的生物量增加，导致FW d的增长率为7.02％^-1与使用f / 2-标准养分供应的未经处理对照组的5.71％FW d ^-1的增长率相比。关于尝试使用最大量的消化物和减少用ASW稀释加工液的必要性，混合比为1：1的加工液C似乎有望用于大规模陆生海洋大型藻类的养殖。但是，将数据转移到其他农业沼气厂的情况需要适应不同的情况，因为改变具有不同沼气底物的沼气发酵罐的进料策略可能会导致沼气消化物中营养成分的巨大差异，从而导致质量和数量的变化。生产的液体中的营养成分。