Skip to main content

Table 3 Results of the survey of operators of biogenic waste-treating biogas plants regarding foam formation in digesters

From: Foam formation in full-scale biogas plants processing biogenic waste

  Description of surveyed biogas plants Survey results
Biogas plant Substrates Capacity   Foam formation Frequency of foam formation Suspected causes of foaming Foam control measures Application of anti-foaming agents
  Saxony        
1 Sewage sludge, separately collected biowaste and commercial waste 55,000 t/a Two digesters á 2,300 m3 Yes Once a year Surfactants, animal protein, etc. Dilution, lowering the level in digester, addition of lime Yes
2 See information to BP E in Table 1    Yes Always Unknown Agitation No
3 Cattle manure, poultry manure, grease separator contents 28,000 t/a Two-stage, mesophilic Yes Only at the beginning Unknown NA NA
4 See information to BP D in Table 1    Yes Formerly Nutrient deficiency, overloading ‘Starvation diet’, adjustment of the feeding system No
5 Poultry manure, green waste, kitchen waste, grease separator contents, old food, paper sludge 40,000 t/a Two-stage, mesophilic NA
6 NA    NA
  Saxony-Anhalt      
7 Biowaste, food waste from discounter 50,000 t/a Coupled dry and liquid production Yes Once No more information available
8 Biogenic waste 30,000 t/a Single-stage, thermophilic No
9 Remains of the bioethanol production 100,000 t/a NA No (foaming problems only in the desulfurization step)
10 Mash from a distillery, process wastewater from a potato peeling plant 2,400 m3/a Single-stage (1,200 m3) Yes NA Tensides NA NA
11 Poultry waste (litter from the poultry keeping, flotation tailings, and wastewater from the slaughter), grease and pizza residues 12.400 t/a Two-stage, mesophilic Yes Twice per year Nutrient deficiency Addition of a nutrient mixture Yes
12 Green waste, commercial waste, biowaste 21.000 t/a Single-stage, mesophilic Yes Regularly Unknown Dilution of substrate with water Yes
13 Food, commercial waste 46.000 t/a NA Yes Once Overfeeding Reduction of the substrate loading No
  Thuringia        
14 Leftovers 72.000 t/a Single-stage, mesophilic Yes Sometimes NA NA NA
15 NA NA NA NA
16 Swine manure, paper fiber residual materials, slaughterhouse waste NA Single-stage, mesophilic Yes Formerly Protein-containing slaughterhouse waste, cellulosic wastes from a paper mill The operator tried miscellaneous, but nothing helped considerably NA
17 Process wastewater from paper processing NA NA No (foaming problems only in the desulfurization step)
18 Cattle manure, biowaste, grease separator contents 30.000 t/a Single stage (2× 800 m3), thermophilic Yes Regularly Grease separator contents Reduction of the substrate loading NA
  1. NA, no answer.