To understand the complex physical and biochemical processes of waste degradation, moisture, temperature, and pressure must be measured in-situ at various depths. These parameters provide an indication of the activity phase of the waste degradation process. Measuring these parameters during waste degradation provides the necessary data to create models, and to work towards optimizing landfill operation.

Dear Dr. Vambol

Municipal solid waste (MSW ) decomposition in a landfill  is a microbial mediated process that occurs in sequential phases as follows:

1. Hydrolysis and aerobic degradation

The first phase is the hydrolysis of polymers (carbohydrates, fats, and proteins), which yields soluble sugars, amino acids, long-chain carboxylic acids, and glycerol. 

2. Hydrolysis & Fermentation

In the second phase, acidogenic bacteria transform the products of the first reaction into short chain volatile acids, ketones, alcohols, hydrogen and carbon dioxide.

3. Fermentation / Acidogenesis

In the third phase, known as acetogenesis, the rest of the acidogenesis products, i.e. the propionic acid, butyric acid and alcohols are transformed by acetogenic or fatty acid oxidizing bacteria into hydrogen, carbon dioxide and acetic acid

4. Methanogens

The fourth and final phase is called methanogenesis. During this stage, microorganisms convert the hydrogen and acetic acid formed by the acid formers to methane gas and carbon dioxide. The most common methanogenic substrates are acetate and CO2 plus H2.

5. Oxidation

In the overall anaerobic decomposition process, hydrolysis is the rate-limiting step when the substrate is complex solid organic material (e.g., C and H), whereas methanogenesis is rate-limiting when the substrate is solubilized.

Hope these are helpful.

Regards,

Ata

Thank you Dr. Isam Issa Omran!

Thank you Dr. Ata Rafiee!

Thank you Dr. Kanhaiya Lal!

Dear Colleagues! I am grateful for your answers. For me this is useful information