Poultry biogas slurry can partially substitute for mineral fertilizers in hydroponic lettuce production

Efficiency of a novel “Food to waste to food” system including anaerobic digestion of food waste and cultivation of vegetables on digestate in a bubble-insulated greenhouse

“…One approach is to combine liquid organic suspensions with mineral nutrients to produce a balanced solution (dos Santos et al, 2013;Pokhrel et al, 2019;Wang et al, 2019). Some also investigate the performance of inorganic, but waste-derived, compounds, such as ammonium compounds from stripping/scrubbing processes and struvite from wastewaters (Sigurnjak, Ivona et al, 2016;Sigurnjak, I. et al, 2019).…”

“…They have also demonstrated how culturing the phototrophic microalgae Euglena gracilis, which can grow with NH4 + as the only N source, can be beneficially included as a preceding step before vegetable cultivation (Takemura et al, 2017) The most common approach to using liquid digestate as a fertiliser in soilless systems is to balance nutrients by adding minerals, usually NO3 - , but also Mg Takemura et al, 2019) and iron (Fe) plus P (Liu et al, 2011). Some investigators have chosen to combine the digestate with a standard mineral fertiliser, rather than adding only the missing nutrients (Kouřimská et al, 2009;Wang et al, 2019). Ronga et al (2018; studied the use of digestate solids used as substrate and digestate liquid fraction used as nutrient solution.…”

“…In addition, high nitrate content in vegetables is a health problem, especially for leafy ones (Wenke et al, 2009). There are many reports showing that substituting conventional mineral fertiliser with digestate reduces the nitrate content of the produce significantly (Liu et al, 2009;Wenke et al, 2009;Lošák et al, 2014;Wang et al, 2019).…”

Biogas digestates are not an effective nutrient solution for hydroponic tomato (Lycopersicon esculentum L.) production under a deep water culture system

“…Studies have reported that the digestate from biogas are high quality nutrient materials rich in macro nutrients such as P, K and in particular, nitrogen (Chen et al., 2017; Sheets et al., 2015; Liu et al., 2011; Yu et al., 2010). Due to the abundance of organic matter, nutrients and the presence of bioactive substances, biogas digestates are often applied directly to the soil as an organic fertilizer together with mineral fertilizers (Wang et al., 2019). However, the response of plants fertilized with biogas digestates is variable depending on manure type, with long term soil application presenting a challenge of heavy metal accumulation in soils (Wang et al., 2019).…”

“…Due to the abundance of organic matter, nutrients and the presence of bioactive substances, biogas digestates are often applied directly to the soil as an organic fertilizer together with mineral fertilizers (Wang et al., 2019). However, the response of plants fertilized with biogas digestates is variable depending on manure type, with long term soil application presenting a challenge of heavy metal accumulation in soils (Wang et al., 2019). Due to the nutrient composition of biogas digestates, the liquid fraction has been evaluated as a potential fertilizer in soils and hydroponic systems.…”