Skip to main content
. 2015 Mar 23;5:9380. doi: 10.1038/srep09380

Table 2. Mean +/− standard deviation (n = 4 unless indicated otherwise; a n = 2 and b n = 3) of bacteria and virus concentrations, two-tailed student's t-test (t) or Wilcoxon Rank Sum test (S) results, and mean percent reduction from domestic wastewater before and after EC treatment. Analyte concentrations are described as less than the process limit of detection (<pLOD) when undetected: c0.01 fecal indicator bacteria cfu/ml, d2.08 × 102 HPyV targets/ml, e1.09 × 102 PMMoV targets/ml, f0.1 MS2 bacteriophage pfu/ml, and g1.00 × 103 Enterococcus spp. targets/ml with IC-NASBA. For molecular analyses, analyte concentrations are considered positive but below the process limit of quantification (+BLOQ) when at least one replicate is +BLOQ: h5.00 × 103 Enterococcus spp. targets/ml (qPCR), i2.00 × 103 Enterococcus spp.targets/ml (IC-NASBA), and l2.19 × 102 PMMoV targets/ml.

    Mean concentration +/− standard deviation per milliliter  
Wastewater Sample Analyte Pre-EC treatment Post-EC treatment Test statistic and p-value % Mean reduction
Raw Enterococcus spp. (cfu) 4.701 × 102 +/− 1.50 × 102 <pLODc S = 26.00, p = 0.0286 >99.998
  Fecal coliform (cfu) 1.95 × 102 +/− 2.29 × 102 < pLODc S = 26.00, p = 0.0286 >99.995
  HPyVs (qPCR target) 2.69 × 103 +/− 8.16 × 102 < pLODd S = 26.00, p = 0.0286 >92.252
  PMMoV (qPCR target) 5.47 × 104 +/− 1.64 × 104 <pLODe S = 26.00, p = 0.0286 >99.800
Tertiary- treated Enterococcus spp. (cfu) 5.43 × 10−2 +/− 2.54 × 10−2 <pLODc S = 26.00, p = 0.0286 >81.567
  Fecal coliform (cfu) 7.40 × 101 +/− 4.05 × 101 < pLODc S = 26.00, p = 0.0286 >99.986
  HPyVs (qPCR target) <pLODd < pLODd N/A N/A
  PMMoV (qPCR target) <pLODe <pLODe N/A N/A
Spiked raw Bacillus subtilis (cfu) 3.80 × 106 +/− 3.74 × 105 3.00 × 100 +/− 1.41 × 100 a S = 26.00, p = 0.0286 >99.99996
  Enterococcus spp. (cfu) 1.25 × 108 +/− 1.56 × 107 2.15 × 100 +/− 4.12 × 100 S = 26.00, p = 0.0286 >99.999998
  Enterococcus spp. (qPCR target) 1.37 × 106 +/− 1.40 × 105 +BPLOQh S = 26.00, p = 0.0286 >99.507
  Enterococcus spp. (NASBA target) 1.15 × 106 +/− 1.72 × 105 <pLODg S = 26.00, p = 0.0286 >99.913
  Fecal coliform (cfu) 1.22 × 106 +/− 2.61 × 105 8.13 × 10−1 +/− 9.10 × 10−1 b t = 9.33, p = 0.0026 >99.99993
  HPyVs (qPCR target) 6.29 × 105 +/− 2.00 × 105 < pLODd S = 26.00, p = 0.0286 >99.967
  PMMoV (qPCR target) 6.38 × 106 +/− 2.35 × 106 <pLODe S = 26.00, p = 0.0286 >99.998
  MS2 bacteriophage (pfu) 3.72 × 104 +/− 3.82 × 103 <pLODf S = 26.00, p = 0.0286 >99.9997
Spiked tertiary- treated Bacillus subtilis (cfu) 3.60 × 106 +/− 3.69 × 105 7.45 × 102 +/− 6.43 × 102 a t = 20.23, p = 0.0003 >99.989
Enterococcus spp. (cfu) 1.44 × 106 +/− 1.03 × 105 5.67 × 101 +/− 7.03 × 101 t = 27.88, p = 0.0001 >99.996
Enterococcus spp. (qPCR target) 1.68 × 106 +/− 1.40 × 105 +BPLOQh S = 26.00, p = 0.0286 >99.702
Enterococcus spp. (NASBA target) 1.56 × 106 +/− 1.04 × 105 +BPLOQi S = 26.00, p = 0.0286 >99.872
Fecal coliform (cfu) 1.47 × 106 +/− 6.24 × 104 3.38 × 101 +/− 4.59 × 101 t = 47.05, p < 0.0001 >99.998
HPyVs (qPCR target) 7.69 × 105 +/− 2.81 × 105 < pLODd S = 26.00, p = 0.0286 >99.973
PMMoV (qPCR target) 1.24 × 107 +/− 6.26 × 106 +BPLOQl S = 26.00, p = 0.0286 >99.998
MS2 bacteriophage (pfu) 2.98 × 104 +/− 5.34 × 103 <pLODf S = 26.00, p = 0.0286 >99.9996