Table 15
TURBIDITY PERFORMANCE STANDARDS
Filtration Technology | Filtered water turbidity (in NTUs) shall be less than or equal to this value in at least 95% of the measurements made each calendar month |
Conventional, Direct and Inline | 0.30 |
Slow Sand | 1.0 |
Diatomaceous Earth | 1.0 |
Alternative Technology | As determined by the department through case-by-case approval of technology, under WAC 246-290-676(2)(b). |
Percent Removal Credit (log)
Filtration Technology | Giardia | Virus | Cryptosporidium | |||
Percent | log | Percent | log | Percent | log | |
Conventional | 99.7 | 2.5 | 99 | 2.0 | 99 | 2.0 |
Direct and in-line | 99 | 2.0 | 90 | 1.0 | 99 | 2.0 |
The department may grant a system using slow sand filtration 99 percent (2-log) Giardia lamblia cyst and Cryptosporidium oocyst removal credit and 99 percent (2-log) virus removal credit, if the system meets the department design requirements under WAC 246-290-676 and meets the minimum turbidity performance requirements in subsection (1) of this section.
The department may grant a system using diatomaceous earth filtration 99 percent (2-log) Giardia lamblia cyst and Cryptosporidium oocyst removal credit and 90 percent (1 log) virus removal credit, if the system meets the department design requirements under WAC 246-290-676 and meets the minimum turbidity performance requirements in subsection (1) of this section.
The department shall grant, on a case-by-case basis, Giardia lamblia cyst, Cryptosporidium oocyst, and virus removal credit for systems using alternative filtration technology based on results of product testing acceptable to the department.
Wash. Admin. Code § 246-290-660
Statutory Authority: RCW 70.119A.180 and 43.20.050. 08-03-061, § 246-290-660, filed 1/14/08, effective 2/14/08. Statutory Authority: RCW 43.20.050 and 70.119A.080. 04-04-056, § 246-290-660, filed 1/30/04, effective 3/1/04. Statutory Authority: RCW 43.20.050(2) and (3) and 70.119A.080. 03-08-037, § 246-290-660, filed 3/27/03, effective 4/27/03. Statutory Authority: RCW 43.02.050 [43.20.050]. 99-07-021, § 246-290-660, filed 3/9/99, effective 4/9/99. Statutory Authority: RCW 43.20.050. 94-14-001, § 246-290-660, filed 6/22/94, effective 7/23/94; 93-08-011 (Order 352B), § 246-290-660, filed 3/25/93, effective 4/25/93.