EnviroMail 064 HK - Introduction to vessel discharge analysis

Intaking and discharging marine water across the global regions is often required in vessel operations

01 APR 2023 ALS

To avoid the growing environmental impact to the marine native species and ecosystem, the vessel is required to test the discharge water after treatment and comply with the related regulations, such US EPA VGP 2013, before discharging to the sea.  
As an accredited lab, ALSHK have provided sampling and testing service for the different testing schemes. The Four (4) main types of water samples are recognised as Ballast water, Gray water Bilgewater and Gas Scrubber Washwater.  

Ballast water

Ballast water is the water held in tanks of ship to increase stability and maneuverability during transit.

Analyte description Method reference Limit of reporting
Heterotrophic Plate Count APHA 9215: A & B 1 CFU/mL
Enterococci USEPA 1600 1 CFU/100mL
Escherichia coli APHA 9223B 2.2 MPN/100mL
Total Residual Chlorine - Field test APHA 4500 Cl: G 0.1 mg/L

 

Gray Water

Gray water refers to the wastewater generated from lavatory sinks, laundry, and water fountains. Below parameters is included but not limited for gray water testing.

Analyte description Method reference Limit of reporting
Biochemical oxygen demand APHA 5210 B 2 mg/L
Faecal coliforms APHA 9222D /
DoE Section 7.8 & 7.9
1 CFU/100mL
Escherichia coli APHA 9223B 2.2 MPN/100mL
Tota suspended solids APHA 2540D 2 mg/L
pH Value - Field test APHA 4500 H: B 0.1 pH unit
Total Residual Chlorine - Field test APHA 4500 Cl: G 0.1 mg/L

 

Bilge water

Oily bilgewater is the mixture of water, oily fluids, lubricants and grease, cleaning fluids and other wastes that accumulate in a vessel from mechanical and operational machinery.

Analyte description Method reference Limit of reporting
HEM (oil and grease) APHA 5520B 5 mg
Hydrocarbon Oil Index
(Total Petroleum Hydrocarbon C10-C36)
USEPA 8015 C10-C14: 20 ug/L C15-C28:
50 ug/L C29-C36: 100 ug/L

 

Gas scrubber washwater

Vessel with a wet exhaust gas scrubber system is required to collect and analyze exhaust gas scrubber sample. During each sampling event at least each of the inlet and outlet samples is required as compassion. The analysis is listed as below.

Analyte description Method reference Limit of reporting
Dissolved & Total Heavy Metals* USEPA 6020 0.1- 5 Lg/L
Nitrate as N UAPHA 4500NO3: I 0.01 mg/L
Nitrite as N UAPHA 4500NO3: I 0.01 mg/L
16 PAHs** USEPA 8270C 0.5 -1 Lg/L
Our standard laboratory turnaround time (TAT) will be 7 working days for testing performed in ALSHK. ALSHK also provide the other testing parameters such as Trihalomethane (THMs), Haloacetic acid (HAA) to meet the US EPA VGP 2013 requirement.

 

References
  1. United States Environmental Protection Agency
    VESSEL DISCHARGE SAMPLE COLLECTION & ANALYTICAL MONITORING - A How-To Reference for EPA’s 2013 Vessel General Permit (VGP) (2014)
  2. International Maritime Organization (IMO) 
    www.imo.org/en/ourwork/environment/pages/ballastwatermanagement.aspx

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