Basics of Composting and the consequences
for plant design and operation

FRIDAY 14 JULY 2023 / 10:00 - 12:30 (GMT+2) 
Werner Bidlingmaier
, Bauhaus University (DE)
Christian Springer, University of Applied Sciences Erfurt (DE)











A - A little bit of microbiology                                              

  • Structure of cells - bacteria: Structure prokaryotic cells - Structure of the eukaryotic cells - Material structure of bacteria 
  • Growth and metabolism of microorganism: Growth phases - Growth curve and growth phases
  • Enzymes: Properties and efficiency of enzymes
  • Monod-Kinetic / Michaelis-Menten-KinetiC: Monod-relation - Coherence between substrate concentration and growth rat - Transfer into practical operation - Relation between substrate concentration and transformation velocity - Reactions 0. order and 1. order
  • Metabolism and energy recovery: Recovery of bio chemically available energy - ATP - Energy storage - Heterotrophic and autotrophic bacteria

B - Aerobic processes (Composting) and design & operation parameters
Aerobic respiration - degradation of carbohydrate, glycolysis, citric acid cycle - Incomplete oxidation - Inorganic substances as hydrogen donors

  • Decomposition of natural substances: Cellulose - Hemicellulose - Starch - Lignin - Protein - Fats
  • Input material for aerobic waste treatment: Mixed Waste - Biowaste - Green Waste - Sludge
  • Physical and chemical material properties – qualification criteria for composting: Water content - pH value - Pore volume / density - Matter - C/N ratio - Heavy metal content
  • Principle of the aerobic decomposition: Role of microorganisms in the degradation process - Degree of decomposition - Proportion of the microbial biomass at the total organic matter - Biochemical degradation processes during composting - Nitrogen dynamic during decomposition
  • Aeration: Aeration by re-stacking - Forced aeration - Control possibilities in an enclosed system - Calculation of needed aeration air / Parameters - Air balance

C - The Plant

  • Flow diagram: Aggregates - Linking of the aggregates
  • Mass balance: Input / Output - Balance of the org. Matter
  • Water balance: Influence parameter - Influence of aeration - Amount of irrigation water - Amount of leachate
  • Energy balance / CO2: External Energy Input - Internal Energy release - Energy Loss - CO2 freight due to construction - CO2 freight due to Operation - CO2 freight due to aerobic Degradation



Werner Bidlingmaier was professor of Waste Management at the Bauhaus-University Weimar, Germany from 1997 to 2011 and full-professor of Waste Management at the University of Essen from 1993 to 1997. Nominated as external lecturer at the University of Stuttgart, Germany in 1991, he was leader of the transfer centre for biological waste treatment Weimar from 1998 to 2001. Additionally, he was Vice-Rector of International development at the Bauhaus-University Weimar. He won the Scientific Award University of Brussels in 1984.
He is author of 12 scientific books, 87 publications and 69 conference papers.

Prof. Dr.-Ing. Christian Springer is Professor for Urban Water Management and Environmental Technology at the University of Applied Sciences Erfurt (DE). Graduated at the Bauhaus-Universität Weimar (DE) in Civil Engineering, with emphasis on Environmental Engineering, he then obtained his PhD on "Energy and CO2-Balance of biological waste treatment on the example of composting and design of an efficiency passport". From 09/2013 to 09/2019 he was Executive Manager of long distance study course “Water and Environment" at the Bauhaus–Universität Weimar (DE). From 10/2013 to 03/2015 he was visiting professor at IIT Madras / Chennai India.