A holistical approach for the minimization of nitrous oxide (N₂O) emissions from brewery wastewater treatment using malt-sprout-derived biochar

Industrial wastewater treatment is regarded as one of the significant greenhouse gas (GHG) resources by the Intergovernmental Panel on Climate Change (IPCC). Nitrous oxide (N₂O) is a major GHG which could be released from agro-industrial wastewater treatment plants. From this point of view, this study investigated the minimization of the nitrous oxide (N₂O) emissions originating from brewery wastewater treatment using malt-sprout-derived biochar. The main objective of the study was the minimization of N₂O emissions from brewery wastewater treatment using the biochar adsorption process. The hypothesis of this study was that biochar could effectively uptake the N₂O from wastewater due to the higher adsorption capacity from the soil. This study was unique in that malt-sprout-derived biochar was used as the N₂O adsorbent for brewery wastewater treatment. The biochar was derived using slow pyrolysis at three different temperatures: 300 (MS1), 400 (MS2), and 550 °C (MS3). The malt sprout and industrial wastewater were ensured from a full-scale brewery industry wastewater treatment plant in Turkey. The correspondence between the N₂O emission and wastewater treatment quality was investigated by Monte Carlo simulation. The gas resulting from wastewater treatment was collected and determined using gas chromatography equipped with an electron capture detector (GC-ECD). N₂O was sampled and measured seasonally, before and after the biochar adsorption process. Furthermore, gas adsorption was performed using the same biochar to verify the N₂O capture capacity of the biochar and minimize the GHG emissions. An average of 25.6% of minimization in N₂O emissions from brewery wastewater was reported using malt-sprout-derived biochar. The simulation results showed that the total Kjeldahl nitrogen (TKN) and ammonium (NH₄-N) had the highest correspondence with N₂O emissions. The highest N₂O uptake capacity was correlated with the biochar derived at the lowest temperature (MS1).