Evaluation of Septic Tank and Subsurface Wetland for

Laboratory Water Quality Analysis
All tests were conducted at NWC laboratory in Bogue according to the analytical
methods listed in Table 4-1.
Table 4-1 Laboratory Test Methods Used in this Evaluation
________________________________________________________________________
TEST METHOD REFERENCE
BOD
TSS
Total Nitrogen
Nitrate
Ammonia
Total Phosphorus
Total Coliform
Fecal Coliform
Standard Method 5210B Unseeded Five Day
Test. Method 4500-O C Azide Modification
for Dissolved Oxygen
Standard Method 2540D
Potassium Persulfate Digestion followed by
Brucine Method 419D
Brucine Method 419D
Hach Salicylate Method 10031
Standard Method 4500-P B Persulphate
Digesion followed by 4500-P D Stannous
Chloride
Standard Method 9221B Presumptive and
Confirmatory
Standard Method 9221B Presumptive and
9221E Confirmatory w/ EC media
30
APHA, 1998
APHA, 1998
D’Ella et al., 1977
APHA, 1975
APHA, 1975
Hach, 2002
APHA, 1998
APHA, 1998
APHA, 1998
Immediately upon arrival at the NWC lab, a portion of each bulk sample was transferred
to 300-ml BOD jars for the unseeded five-day BOD test (see Figure 4-5). Multiple tube
fermentation coliform presumptive tests also began the same day. Unused grab samples
remained in their original container and were placed in the BOD incubator/refrigerator.
Nutrient tests were usually performed one day after sample collection. Total nitrogen
was measured by a Potassium Persulfate digestion method (D’Ella et al., 1977) which
converts all nitrogen to nitrates. All nitrate tests followed the Brucine Method 419 D