Biosolids Permit Application Process Key - Part 1

Do you need to apply for coverage?

Step 1: Determining if you need to obtain permit coverage. If you are Treatment Works Treating Domestic Sewage (TWTDS) you must obtain coverage under the state biosolids permit program. If you are not a TWTDS you are not required to obtain coverage under the state biosolids permit program.

Are you a Treatment Works Treating Domestic Sewage?

The term Treatment Works Treating Domestic Sewage (TWTDS) comes from federal rules. Congress directed the U.S. EPA to develop standards for biosolids and to implement those standards in permits. Facilities subject to the federal permitting program are referred to as Treatment Works Treating Domestic Sewage. This term was also adopted for the state rules and permit system for consistency.

Basically, a facility that treats sewage or changes the character of biosolids so that different regulatory requirements apply is a treatment works treating domestic sewage. Your facility is a treatment works treating domestic sewage if it is:

• a publicly owned sewage treatment facility of any size
• a privately owned sewage treatment facility of any size (see exception for Industrial facilities below)
• a federal or state owned sewage treatment facility
• a septage management facility
• a compost facility and uses biosolids as one of the feedstocks
• a treatment works at an industrial facility that treats only sewage with no industrial influent
• a designated beneficial use facility
• designated as a treatment works treating domestic sewage under WAC 173-308-310(1)(b)

NOTE: Treatment works treating domestic sewage located on Native American lands are not subject to the state permit program and should contact U.S. EPA. Activities carried out by these facilities on non-Native American lands are subject to state jurisdiction.

You are not a TWTDS (unless you have been specifically designated) if:

• you are a septic tank pumper who does not apply or treat septage (septic tanks and similar systems are also not considered TWTDS)
• you use exceptional quality biosolids in a process to manufacture topsoil or soil amendments
• you are an industrial facility treating mixed sewage and industrial influent
• you only apply biosolids to the land under contract to a treatment works
• you only own land where biosolids are applied

NOTE: Those persons and facilities that are not subject to the permitting requirements of WAC 173-308-310, but which engage in applicable biosolids management activities, must still comply with any applicable requirements of the rule.

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