Class A Biosolids vs. Class B in Plain English

Class A

Class B

In addition to meting the requirements in one of the six alternatives listed below, fecal coliform or Salmonella sp. Bacteria levels must meet specific density requirements at the time of biosolids use or disposal or when prepared for sale or give-away (see Chapter Five [PDF] of this guidance).

The requirements in one of the three alternatives below must be met.

Alternative 1: Thermally Treated Biosolids
Use one of four time-temperature regimens.

Alternative 1: Monitoring of Indicator Organisms
Test for fecal coliform density as an indicator for all pathogens at the time of biosolids use or disposal

Alternative 2: Biosolids Treated in a High pH-High Temperature Process
Specifies pH, temperature, and air-drying requirements

Alternative 2: Use of PSRP
Biosolids are treated in one of the Processes to Significantly Reduce Pathogens (PSRP) (see Table 5-7)

Alternative 3: For Biosolids Treated in Other Processes
Demonstrate that the process can reduce enteric viruses and viable helminth ova. Maintain operating conditions used in the demonstration.

Alternative 3: Use of Processes Equivalent to PSRP
Biosolids are treated in a process equivalent to one of the PSRPs, as determined by the permitting authority

Alternative 4: Biosolids Treated in Unknown Process
Demonstration of the process is unnecessary. Instead, test for pathogens—Salmonella sp. or fecal coliform bacteria, enteric viruses, and viable helminth ova—at the time the biosolids are used or disposed of or are prepared for sale or give-away.

Alternative 5: Use of PFRP
Biosolids are treated in one of the Processes to Further Reduce Pathogens (PFRP) (see Table 5-4)

Alternative 6: Use of a Process Equivalent to PFRP
Biosolids are treated in a process equivalent to one of the PFRPs, as determined by the permitting authority