Section 58.01.16.510 - FACILITY AND DESIGN STANDARDS FOR MUNICIPAL WASTEWATER TREATMENT OR DISPOSAL FACILITIES: SUPPLEMENTAL TREATMENT PROCESSES01.Chemical Treatment. Many chemicals in various forms can be applied in wastewater treatment to aid in nutrient removal, pH adjustment, enhanced clarification, and sludge conditioning. Chemicals must be evaluated for each specific treatment process and must be compatible with other liquids, solids and air treatment processes. Laboratory tests such as jar tests or pilot-scale studies on actual process wastewater shall be used to select appropriate chemicals and dosage ranges.a. Phosphorus removal. Chemical phosphorus removal from wastewater involves the addition of metal salts (aluminum or iron) or lime to wastewater to form insoluble phosphate precipitates, removal of the precipitate from the wastewater, and disposal of the precipitate with the settled sludge. Many process options are available, and the designer shall select the chemical to insolubilize the phosphorus, estimate the dosage requirements, and select the point of chemical addition.b. Nitrogen Removal. Several chemical processes have been used for nitrogen removal. The three (3) major processes include breakpoint chlorination, selective ion exchange, and air stripping. Although these processes are technically feasible ways of removing nitrogen, the Department does not anticipate widespread use of chemicals for nitrogen removal, and justification to do so shall be demonstrated in the Preliminary Engineering Report.c. pH Adjustment. A common chemical process used in wastewater treatment is pH adjustment. Several methods are available to neutralize or adjust low pH wastewater. The methods used shall be mixing acid wastes with lime slurries, or adding the proper amount of concentrated caustic soda (NaOH) or soda ash (Na2CO3) as determined in the Preliminary Engineering Report.d. Enhanced Primary Clarification. When settling aids are used during the primary clarification process to enhance solids removal in the primary treatment process, the additional solids volume shall be accounted for in pumping, solids handling, stabilization, and disposal processes. The coagulant shall be added and mixed before the sedimentation process. Flocculants, if used, shall be added after the coagulant. The design shall provide for chemical addition points at several locations to give process personnel the opportunity to adjust for optimum performance.02.Filtration for Tertiary Treatment. Details for plants with tertiary treatment utilizing filtration shall be submitted and approved in the Preliminary Engineering Report.a. Membranes. In addition to requirements of Section 411, details shall include plant layout, calculations for hydraulic capacity and air required, membrane technology considered and membrane type and model selected, results from similar type filtration plants already in operation, and anticipated sludge production.b. Media. In addition to requirements of Section 411, details shall include plant layout, calculations for hydraulic capacity, media considered and media type selected, results from similar type filtration plants already in operation, and anticipated sludge production.c. Cloth. In addition to requirements of Section 411, details shall include plant layout, calculations for hydraulic capacity, technology considered and type and model selected, results from similar type filtration plants already in operation, and anticipated sludge production.d. Reverse Osmosis. In addition to requirements of Section 411, details shall include plant layout, calculations for hydraulic capacity required, technology considered and type and model selected, results from similar type filtration plants already in operation, and anticipated sludge production.Idaho Admin. Code r. 58.01.16.510