SECTION .0600 ‑ RAW SURFACE WATER FACILITIES

15A NCAC 18C .0601      IMPOUNDMENTS: PRE-SETTLING RESERVOIRS

(a)  Construction of a pre-settling reservoir shall be required if wide and rapid variations in turbidity, bacterial concentrations, or chemical qualities occur, or where the following raw water quality standards are not met: turbidity - 150 NTU, coliform bacteria - 3000/100 ml, fecal coliform bacteria - 300/100 ml, or color - 75 CU. If impoundment of the water supply stream does not or will not provide raw water of acceptable quality, a pre-settling reservoir located outside the watershed or catchment area shall be required.

(b)  The Department shall approve alternatives to pre-settling reservoirs if a supplier of water demonstrates that engineered pretreatment providing an additional treatment barrier to low raw water quality will be installed and that the overall designed treatment process will comply with all other applicable requirements of this Subchapter. Pilot plant studies under Rule .0714 of this Subchapter shall be required to demonstrate treatment effectiveness unless operational data demonstrating treatment effectiveness for the variety of water quality that is experienced at the treatment facility are already available.

(c)  The Department shall approve capacity increases at existing surface water treatment facilities without addition or up-sizing of pre-settling reservoirs if:

(1)           historical data or full-scale pilot studies demonstrate that the plant will provide treatment in accordance with this Subchapter without additional pre-settling; or

(2)           the use of alternative technology alleviates the need for additional pre-settling.

History Note:        Authority G.S. 130A-315; 130A-317; P.L. 93-523;

Eff. January 1, 1977;

Readopted Eff. December 5, 1977;

Readopted Eff. July 1, 2019.