2024-22013. Vessel Incidental Discharge National Standards of Performance

Table 1 to Paragraph (b)(2)(ii)

Discharge water flowrate before any seawater addition for pH control (t/MWh)	Numeric discharge standard (µg/L PAHphe equivalents)	Measurement technology
0-1	2,250	Ultraviolet light
2.5	900	- ″ -
5	450	Fluorescence a
11.25	200	- ″ -
22.5	100	- ″ -
45	50	- ″ -
90	25	- ″ -
a  For any Flow Rate greater than 2.5 t/MWh, Fluorescence technology must be used.

(iii) The continuous PAHphe numeric discharge standard may be exceeded by 100% for up to 15 minutes in any 12-hour period.

(3) Turbidity/suspended particulate matter.

(i) The washwater treatment system must be designed to minimize suspended particulate matter, including but not limited to heavy metals and ash.

(ii) The maximum continuous turbidity in the discharge must be no greater than 25 FNU (formazin nephlometric units) or 25 NTU (nephlometric turbidity units) or equivalent units above the inlet water turbidity. However, to account for periods of high inlet turbidity, readings must be a rolling average over a 15-minute period to a maximum of 25 FNU or NTU. This standard applies downstream of any washwater treatment equipment including any reactant dosing unit but upstream of any seawater addition for control of pH prior to discharge.

(iii) For an aggregated 15-minute period in any rolling 12-hour period, the continuous turbidity discharge limit may be exceeded by 20%.

(4) Nitrates plus nitrites:

(i) The washwater treatment system must prevent the discharge of nitrates plus nitrites beyond that associated with a 12% removal of NO_X from the exhaust, or beyond 60 mg/L normalized for a discharge rate of 45 tons/MWh, whichever is greater, where the MW refers to the MCR or 80% of the power rating of all those fuel oil combustion units whose EGCS discharge water nitrates plus nitrites are being monitored at that point. This standard applies downstream of any washwater treatment equipment including any reactant dosing unit but upstream of any seawater addition for control of pH prior to discharge. The 60-mg/L limit is adjusted upward for lower washwater flow rates per MWh, and vice-versa, and the applicable permit limits are contained in table 2 to paragraph (b)(4)(i) of this section.

Table 2 to Paragraph (b)(4)(i)

Discharge water flowrate before any seawater addition for pH control (t/MWh)	Numeric discharge standard (mg/L nitrate + nitrite)
0-1	2,700
2.5	1,080
5	540
11.25	240
22.5	120
45	60