15A NCAC 02U .0402       DESIGN CRITERIA FOR WASTEWATER TREATMENT FACILITIES – NON-CONJUNCTIVE SYSTEMS

(a)  The requirements in this Rule apply to all new and expanding non-conjunctive facilities, as applicable.

(b)  Aerated flow equalization facilities shall be provided with a capacity based upon either a representative diurnal hydrograph or at least 25 percent of the daily system design flow.

(c)  Dual facilities shall be provided for all essential treatment units.

(d)  Continuous on-line monitoring and recording for turbidity or particle count and flow shall be provided prior to storage, distribution, or utilization.

(e)  Effluent from the treatment facility shall be discharged to a five-day side-stream detention pond if either the turbidity exceeds 10 NTUs or if the permitted pathogen levels cannot be met.  The facility shall have the ability to return the effluent in the five-day side-stream detention pond back to the head of the treatment facility.

(f)  There shall be no public access to the wastewater treatment facility or the five-day side-stream detention pond.  The five-day side-stream detention pond shall have either a liner of natural material at least one foot in thickness and having a hydraulic conductivity of no greater than 1 x 10-6 centimeters per second when compacted, or a synthetic liner of sufficient thickness to exhibit structural integrity and an effective hydraulic conductivity no greater than that required of the natural material liner. Liner requirements of the five-day side-stream detention pond or separation distances between the bottom of the five-day side-stream detention pond and the groundwater table may be reduced if it can be demonstrated by predictive calculations or modeling methods that satisfy the Director, that construction and use of the five-day side-stream detention pond will not result in contravention of assigned groundwater standards at the compliance boundary.

(g)  The storage basin shall have either a liner of natural material at least one foot in thickness and having a hydraulic conductivity of no greater than 1 x 10-6 centimeters per second when compacted, or a synthetic liner of sufficient thickness to exhibit structural integrity and an effective hydraulic conductivity no greater than that required of the natural material liner. Liner requirements of the storage basin or separation distances between the bottom of storage basin and the groundwater table may be reduced if it can be demonstrated by predictive calculations or modeling methods that satisfy the Director, that construction and use of the storage basin will not result in contravention of assigned groundwater standards at the compliance boundary.

(h)  Automatically activated standby power supply onsite, capable of powering all essential treatment units under design conditions shall be provided.

(i)  The permit shall require an operator certified by the Water Pollution Control System Operators Certification Commission (WPCSOCC) of a grade equivalent or greater than the facility classification to be on call 24 hours per day.

(j)  By-pass and overflow lines are prohibited.

(k)  Multiple pumps shall be provided if pumps are used.

(l)  A water-tight seal on all treatment/storage units or minimum of two feet protection from 100-year flood shall be provided.

(m)  Reclaimed water irrigation system design shall not exceed the recommended precipitation rates in the soils report prepared pursuant to Rule .0202 of this Subchapter.

(n)  A minimum of 30 days of residual storage shall be provided.

(o)  Utilization areas shall be designed to maintain a one-foot vertical separation between the seasonal high water table and the ground surface.

(p)  Influent pump stations shall meet the sewer minimum design criteria as provided in 15A NCAC 02T .0300.

(q)  Type 2 reclaimed water treatment facilities shall provide dual disinfection systems containing UV disinfection or equivalent and chlorination or equivalent to provide pathogen control.

(r)  Type 2 reclaimed water treatment facilities shall provide documentation that the combined treatment and disinfection processes are capable of the following:

(1)           log 6 or greater reduction of E. coli;

(2)           log 5 or greater reduction of Coliphage; and

(3)           log 4 or greater reduction of Clostridium perfringens.

 

History Note:        Authority G.S. 143-215.1; 143-215.3(a);

Eff. June 18, 2011.