BIOGAS, COMPOSTING & ANIMAL BY-PRODUCTS

Biogas and composting plants shall operate in accordance with the standards detailed in the following circulars issued by the Greek Ministry of Rural Development and Food (YPAAT):

According to the current legislative framework, microbiological analyses are required for the initial approval of the plants, as well as for the plants’ own tests on raw materials (animal by-products and derived products) and degradation residues.  

In particular, test results obtained following specific sampling and testing protocols are expected to comply with the official microbiological criteria (‘standards’) shown below:

A. Degradation residues after anaerobic and thermal treatment in a biogas digester:

A. Degradation residues after anaerobic and thermal treatment in a biogas digester:

  • The following criteria shall apply for samples collected from the bioreactor: (a) while the animal by-product transformation process is taking place, or (b) soon after the transformation is complete:

Escherichia coli: n = 5, c = 1, m = 1 000, M = 5 000 in 1 g, or

Enterococcaceae: n = 5, c = 1, m = 1 000, M = 5 000 in 1 g and

  • Samples shall also be collected during, or soon after storage, before the transformed organic residue is disposed, where the following criteria shall apply:

Salmonella spp.: Not detected in 25 g: n = 5, c = 0, m = 0, M = 0

During the testing phase of the biogas operation, degradation residues should be microbiologically tested on a weekly basis, for 4 consecutive weeks and by performing 4 consecutive tests for each bacterial parameter. If any of the samples fails to comply with any of the standards, then the whole 4-week sampling and testing procedure should be repeated right from the start.

Once the plant goes into full operation and for as long as there is no non-conformity of the test results to the official microbiological standards, the same sampling and testing protocols shall be performed on a 6-month basis.

A. Degradation residues after anaerobic and thermal treatment in a biogas digester:

  • The following criteria shall apply for samples collected from the bioreactor: (a) while the animal by-product transformation process is taking place, or (b) soon after the transformation is complete:

Escherichia coli: n = 5, c = 1, m = 1 000, M = 5 000 in 1 g, or

Enterococcaceae: n = 5, c = 1, m = 1 000, M = 5 000 in 1 g and

  • Samples shall also be collected during, or soon after storage, before the transformed organic residue is disposed, where the following criteria shall apply:

Salmonella spp.: Not detected in 25 g: n = 5, c = 0, m = 0, M = 0

During the testing phase of the biogas operation, degradation residues should be microbiologically tested on a weekly basis, for 4 consecutive weeks and by performing 4 consecutive tests for each bacterial parameter. If any of the samples fails to comply with any of the standards, then the whole 4-week sampling and testing procedure should be repeated right from the start.

Once the plant goes into full operation and for as long as there is no non-conformity of the test results to the official microbiological standards, the same sampling and testing protocols shall be performed on a 6-month basis.

B. Validation of an, alternative to pasteurization, decontamination procedure for manure and certain animal by-products (ABP) of category 2 and 3

B. Validation of an, alternative to pasteurization, decontamination procedure for manure and certain animal by-products (ABP) of category 2 and 3

  • Samples should first be inoculated with an appropriate level of certain “biological indicators” and then subjected to an alternative decontamination procedure for validation purposes. In order for the alternative procedure to be considered as equivalent to replace pasteurization, the following criteria shall be met:
  • 5 log10 reduction of Enterococcus faecalis or Salmonella Seftenberg
  • 5 log10 reduction of heat-resistant viruses
  • 5 log10 reduction of heat-resistant parasites

B. Validation of an, alternative to pasteurization, decontamination procedure for manure and certain animal by-products (ABP) of category 2 and 3

  • Samples should first be inoculated with an appropriate level of certain “biological indicators” and then subjected to an alternative decontamination procedure for validation purposes. In order for the alternative procedure to be considered as equivalent to replace pasteurization, the following criteria shall be met:
  • 5 log10 reduction of Enterococcus faecalis or Salmonella Senftenberg
  • 5 log10reduction of heat-resistant viruses
  • log10 reduction of heat-resistant parasites
C. Processed manure and degradation residues following digestion without heat treatment

C. Processed manure and degradation residues following digestion without heat treatment

  • Test results of samples collected during or soon after processing, shall comply with the following criteria:

Escherichia coli: n = 5, c = 5, m = 0, M = 1 000 in 1 g, or

Enterococcaceae: n = 5, c = 5, m = 0, M = 1 000 in 1 g and

  • Test results of samples collected during or soon after storage, shall also comply with the following criteria:

Salmonella spp.: Not detected in 25 g: n = 5, c = 0, m = 0, M = 0

C. Processed manure and degradation residues following digestion without heat treatment

  • Test results of samples collected during or soon after processing, shall comply with the following criteria:

Escherichia coli: n = 5, c = 5, m = 0, M = 1 000 in 1 g, or

Enterococcaceae: n = 5, c = 5, m = 0, M = 1 000 in 1 g and

  • Test results of samples collected during or soon after storage, shall also comply with the following criteria:

Salmonella spp.: Not detected in 25 g: n = 5, c = 0, m = 0, M = 0

At SCIELAB we can responsibly test and report your compliance.