Section Env-Wq 711.03 - Secondary Settling Tanks: Design Criteria for Solids Loading(a) Secondary settling tanks shall be designed integrally with the design of the aeration basins and sludge return facilities. Secondary settling tank sizing shall be based on solids loadings, sludge settleability, settled sludge concentration, and return sludge rates.(b) Solids loading shall be calculated as follows:(1) Peak solids loading rate shall be computed based on the design mixed liquor suspended solids (MLSS) under aeration and the design maximum daily flow rate plus the corresponding recycle rate required to maintain the design MLSS;(2) Allowable solids loading rates shall be determined using solids flux analysis, expected sludge characteristics, and a settling tank factor of safety of 1.3 to 1.5 times the maximum daily flow; and(3) Settling tank area shall be determined based on a solids flux analysis as specified in section 6.3.5.4 of TR-16, 2011 Edition, available as noted in Appendix B.N.H. Code Admin. R. Env-Wq 711.03
Adopted byVolume XXXIV Number 46, Filed November 13, 2014, Proposed by #10693, Effective 10/15/2014, Expires10/15/2024.