INCREASING THE BASELOAD CAPACITY OF BIOWASTE FERMENTATION PLANTS THROUGH OPTIMISED SUBSTRATE MANAGEMENT

• Main Authors: Sprafke, Jan, Engler, Nils, Thabit, Qahtan, Nelles, Michael, Schuech, Andrea
• Format: Article
• Language: English
• Published: CISA Publisher 2020-02-01
• Series: Detritus
• Online Access: https://digital.detritusjournal.com/doi/13905-286

This paper presents a survey to determine the influence of impurities and green waste on anaerobic biowaste treatment, comparing the current common biowaste management system with a proposed future system. The results imply that it is possible to increase the specific biogas yield and the baseload capacity by means of an adapted biowaste management system. To analyse a possible correlation between biogas yield and biowaste composition from urban or rural areas the quality and quantity of biowaste was evaluated in a long-term research programme. August was the month with the maximum percentage of 69% green waste in biowaste, compared to February with a minimum proportion of 14%. The specific biogas yield of biowaste is in the range of 91 to 160 m³/tOS. The evaluation showed that, as expected, seasonal fluctuations in weather affected the proportion of garden and park waste (green waste) as well as impurities. Moreover, the proportion of green waste and impurities affects the substrate quality and degradability of biowaste. The investigated biowaste fermentation plant is not able to generate sufficient baseload for the reasons described above. Other reasons for this limitation include maintenance work, plant operation in part-load range and plant capacity limitations concerning the CHP module, digester capacity and pipes for gas transportation. The best ratio between organic fraction and impurities is obtained from biowaste from rural areas, while gas yields from urban areas are more constant and less volatile. Based on these findings, the increasing of the baseload capacity of waste fermentation plants can be achieved by: Optimisation of process flows (substrate management, preparation, post-treatment); Use of co-substrates in compliance with legal requirements; Determination and consideration of key figures.