"Activated sludge process" means a biological wastewater treatment process in which a mixture of wastewater and activated sludge is agitated and aerated. The activated sludge is subsequently separated from the treated wastewater by sedimentation or filtration and wasted or returned to the process as needed.

"Biennium" means a two-year period from July 1st of each odd year through June 30th of the next odd year.

"Biofiltration" means the process of passing a liquid through a biological filter that contains fixed media on surfaces which develop zoogleal films that absorb and adsorb fine suspended, colloidal, and dissolved solids and release end products of biochemical action.

"Certificate" means the certificate of competency issued by the director stating that an individual has met the requirements for a specific classification in the wastewater treatment plant operator certification program.

"Certificate holder" means the individual to whom a certificate is issued.

"CEU" means continuing education unit that is a nationally recognized unit of measurement similar to a college credit. One CEU is awarded for every ten contact hours of participation in an organized continuing education experience under responsible sponsorship, capable direction, and qualified instruction. Forty-five CEUs is equivalent to one year of education.

"College credits" means credits earned toward a college degree or in course work that is relevant to the operation of a wastewater treatment plant. One year of college is equivalent to forty-five quarter credits or thirty semester credits.

"Department" means the Washington state department of ecology.

"Director" means the director of the department of ecology or the director's designee.

"Effective date of a revocation order" means the date a revocation period ends.

"Extended aeration" means a modification of the activated sludge process that uses long aeration periods and long mean cell residence times for aerobic digestion of the biological mass by endogenous respiration and promotes the growth of nitrifying organisms.

"Exam" means a test recognized by the department to determine the competency of operators for each certification level.

"Exam cycle" means a five-year period from the time a new exam is released.

"Full certification" means holding a Group I, II, III, or IV wastewater treatment plant operator certification issued by the department. Full certification does not include operator in training certifications.

"GED" means a general education development certificate issued by a recognized education institution. A GED is equivalent to a high school diploma.

"Group" and "class" for the purpose of operator certification and wastewater treatment plant classification are the same.

"Lagoon" means any large lined holding or detention pond, usually with earthen dikes, that is used to contain wastewater while sedimentation and biological stabilization occurs.

"Lead operator of a shift" means the individual onsite at a wastewater treatment plant whose primary responsibility is to operate and maintain the wastewater treatment plant on a regularly run shift. The lead operator of a shift is subordinate to the operator in responsible charge. An OIT may not be the lead operator of a shift.

"MBR (membrane bioreactor)" means an activated sludge process that combines a suspended growth biological reactor with solids removal via filtration in a single unit.

"Operating experience" means the routine performance of duties, onsite at a wastewater treatment plant, that affect plant performance or effluent quality.

"Operating shift" means a designated period of time in which a certified operator makes decisions or takes actions that may affect plant operations.

"Operator" means an individual who performs routine duties, onsite at a wastewater treatment plant, that affect plant performance or effluent quality.

"Operator in responsible charge" means the individual who is designated by the owner as the person routinely onsite and in direct charge of the overall operation and maintenance of a wastewater treatment plant. An OIT may not be the operator in responsible charge.

"Operator in training (OIT)" means an individual who passed an exam but has less than the required amount of operating experience to meet the full certification requirements.

"Operator in training certificate" means a certificate issued by the department to an operator in training that is working towards full certification.

"Owner" means in the case of:

• A town or city, the city or town acting through its chief executive officer or the lessee if operated under a lease or contract;

• A county, the chairman of the county legislative authority or the chairman's designee;

• A sewer district, board of public utilities, association, municipality or other public body, the president or chairman of the body or the president's or chairman's designee;

• A privately owned wastewater treatment plant, the legal owner.

"Primary wastewater treatment" means clarification to physically remove settleable and floatable materials in addition to the removal of raw biosolids and preliminary treatment; preliminary treatment consists of one or more of the following: Screening, grit removal and comminution, and grinding.

"Professional growth" means training that is directly related to improving competencies in areas that relate to operating and maintaining a wastewater treatment plant.

"Professional growth reporting period" means a designated period of time, not less than three years, in which a certified operator completes the professional growth requirement in WAC 173-230-300.

"Provisional certificate" means a one-time certificate issued without passing an exam if the plant classification increases solely due to a reclassification based on the criteria in Table 4.

"Reclaimed water" means water derived in any part from a wastewater with a domestic wastewater component that has been adequately and reliably treated to meet the requirements of chapter 173-219 WAC, so that it can be used for beneficial purposes. Reclaimed water is not considered a wastewater.

"Reclaimed water facility" means the treatment plant, equipment, storage, conveyance devices, and dedicated sites for reclaimed water generation.

"Reciprocity" means the mutual exchange of a valid out-of-state wastewater treatment plant operator's certificate achieved by passing a department approved exam for an equivalent level of certification without further examination.

"Revocation" means the department invalidates an operator's certificate.

"Routine" means duties that are performed on a regular basis and not sporadically.

"Sequencing batch reactor (SBR)" means a fill-and-draw activated sludge system where sewage is added to one of several tanks which are alternately filled, aerated, settled, and decanted. A typical system applies a predetermined sequence of operations based on the flow and other inputs using a programmable logic controller and is uniquely suited for wastewater treatment applications characterized by low or intermittent flow conditions.

"Standardized exam" means a national exam with standard questions for all states and not customized for individual states.

"Suspension" means to make an operator's certificate temporarily invalid.

"Tertiary" means advanced physical/chemical or biological treatment of wastewater beyond the conventional secondary stage to remove additional suspended and dissolved substances. These substances may include phosphorus and nitrogen, a high percentage of suspended solids, dissolved inorganic solids, toxic compounds, microorganisms, and complex organic compounds.

"Wastewater certification program coordinator" means an employee of the department who is appointed by the director and who administers the wastewater treatment plant operator certification program.

"Wastewater collection system" means any system of lines, pipes, manholes, pumps, liftstations, or other facilities used to collect and transport wastewater.

"Wastewater treatment plant" means a facility used to treat any liquid or waterborne waste of domestic origin or a combination of domestic, commercial or industrial origin, and that, by its design, requires the presence of an operator for its operation. It does not include any facility used exclusively by a single family residence, septic tanks with subsoil absorption, industrial wastewater treatment plants, or wastewater collection systems.

"Wetland treatment" means natural treatment system wetlands intentionally constructed and managed for the primary purpose of wastewater treatment.