The tables below summarize the results of the chemical and microbiological analysis conducted to evaluate the quality of the product water generated by WH2Osystems’s Forward Osmosis Recycling System (FORS) in comparison to potable water standards. As shown below, the effluent meets all potable standards, although it can be legally used only for non-potable applications. The system is also compliant with NSF/ANSI 350.
A more recent water quality analysis has been conducted by Stanford University in 2019 on behalf of a Silicon Valley high-tech giant to validate FORS with different sources of greywater and blackwater generated by a variety of commercial and residential buildings. In all cases, the product water met and exceeded all legal reuse standards. The results of these test are available upon request and will be soon published on a scientific journal.
Potable water standards are based on the Environmental Protection Agency (EPA) guidelines and the National Primary Drinking Water Regulations (NPDWR). These standards are applicable to water purification systems that have been operating for more than 30 days. The effluent of the system has been periodically collected and tested using the following analytical methods:
- EPA method 624, organic chemical analysis by gas chromatography/mass spectrometer (GC/MS).
- EPA method 625, base/neutrals and acids (semivolatile organic compounds and polychlorinated biphenyls) by gas chromatography/mass spectrometry (GC/MS)
- EPA method 8321B, solvent-extractable nonvolatile compounds by high-performance liquid chromatography/thermospray/mass spectrometry (HPLC/TS/MS) or ultraviolet (UV) detection.
- EPA method 608, organochlorine pesticides and polychlorinated biphenyls by gas chromatography.
- EPA method 300.0, inorganic anions by ion chromatography.
- EPA method 300.1, determination of inorganic anions in drinking water by ion chromatography.
- EPA method 200.7, metals and trace elements in water and wastes by inductively coupled plasma atomic emission spectrometry.
- EPA method 552.2, determination of haloacetic acids and dalapon in drinking water by liquid-liquid extraction, derivatization and gas chromatography with electron capture detection.
- Standard method 4500 CN-C, cyanides amenable to chlorination after distillation by spectroscopy (colorimetry; photometry)
- EPA method 420.1, phenols by spectrophotometry.
- EPA method 900.0, measurement of gross alpha and gross beta.
- EPA method 200.8, determination of trace elements by inductively coupled plasma mass spectrometry (ICP-MS).
- EPA method 906.0, tritium analysis by liquid scintillation counting.
| Chemio-pshysical Properties | Standards (mg/L) | Results (mg/L) |
| Turbidity | 1NTU | 0.18 NTU |
| Odor | Acceptable | Acceptable |
| Color | 15 CU | - |
| pH | 6.5-8.5 | 7.2 |
| TDS | 500 | 104 |
| Inorganic compounds | Standards (mg/L) | Analysis method (mg/L) | Method detection limit (mg/L) | Practical quantitation limit (mg/L) | Results (mg/L) |
| Antimony | 0.006 | E200.7 | 0.004 | 0.01 | ND |
| Arsenic | 0.01 | E200.7 | 0.005 | 0.01 | ND |
| Asbestos | 7 MFL | E600/R-94/134 | - | - | ND |
| Barium | 2 | E200.7 | 0.002 | 0.01 | ND |
| Beryllium | 0.004 | E200.7 | 0.002 | 0.005 | ND |
| Cadmium | 0.005 | E200.7 | 0.001 | 0.005 | ND |
| Chromium | 0.1 | E200.7 | 0.002 | 0.005 | ND |
| Copper | 1 | E200.7 | 0.003 | 0.01 | ND |
| Cyanide | 0.2 | A4500CE | 0.01 | 0.03 | ND |
| Fluoride | 4 | E300.0 | 0.04 | 0.5 | ND |
| Iron | 0.3 | E200.7 | 0.002 | 0.3 | ND |
| Lead | 0.015 | E200.7 | 0.005 | 0.015 | ND |
| Manganese | 0.05 | E200.7 | 0.003 | 0.05 | ND |
| Mercury | 0.05 | E245.1 | 0.00005 | 0.0002 | ND |
| Nitrate | 10 | E300.0 | 0.077 | 0.5 | ND |
| Nitrite | 1 | E300.0 | 0.095 | 0.5 | ND |
| Selenium | 0.05 | E200.7 | 0.004 | 0.02 | ND |
| Silver | 0.1 | E200.7 | 0.002 | 0.005 | ND |
| Sulfate | 250 | E300.0 | 0.089 | 1 | ND |
| Thallium | 0.002 | E200.7 | 0.004 | 0.01 | ND |
| Zinc | 5 | E200.7 | 0.002 | 0.01 | 0.012 |
| Organic compounds | Standards (mg/L) | Analysis method (mg/L) | Method detection limit (mg/L) | Practical quantitation limit (mg/L) | Results (mg/L) |
| 1,1,1-Trichloroethane | 0.2 | E624 | 0.1 | 0.5 | ND |
| 1,1,2-Trichloroethane | 0.005 | E624 | 0.14 | 0.5 | ND |
| 1,1-Dichloroethylene | 0.007 | E624 | 0.16 | 0.5 | ND |
| 1,2,4-Trichlorobenzene | 0.07 | E625 | 0.95 | 4 | ND |
| 1,2-Dibromo-3-chloropropane | 0.0002 | E608 | 40.3 | 118 | ND |
| 1,2-Dichloroethane | 0.005 | E624 | 0.12 | 0.5 | ND |
| 1,2-Dichloropropane | 0.005 | E624 | 0.12 | 0.5 | ND |
| 2,4-D | 0.07 | E8151A | - | - | ND |
| Benzene | 0.005 | E624 | 0.1 | 0.5 | ND |
| Benzo(a)pyrene | 0.0002 | E625 | 0.25 | 3.6 | ND |
| Carbon tetrachloride | 0.005 | E624 | 0.07 | 0.5 | ND |
| Chlordane | 0.002 | E608 | 0.13 | 0.25 | ND |
| Chlorobenzene | 0.1 | E624 | 0.11 | 0.5 | ND |
| Cis-1,2-Dichloroethylene | 0.07 | E624 | 0.13 | 0.5 | ND |
| Di(2-ethylhexyl)phthalate | 0.006 | E625 | 0.31 | 12 | ND |
| Dichloromethane | 0.005 | E624 | 0.27 | 1 | ND |
| Dinoseb | 0.007 | E8151A | - | - | ND |
| Endrin | 0.002 | E608 | 0.004 | 0.02 | ND |
| Ethylbenzene | 0.7 | E624 | 0.11 | 0.5 | ND |
| Ethylene dibromide | 0.00005 | E624 | 0.28 | 4.2 | ND |
| Heptachlor | 0.0004 | E608 | 0.004 | 0.02 | ND |
| Heptachlor hepoxide | 0.0002 | E608 | 0.005 | 0.02 | ND |
| Hexachlorobenzene | 0.001 | E625 | 0.65 | 4 | ND |
| Hexachlorocyclopentadiene | 0.05 | E625 | 0.36 | 20 | ND |
| Methoxychlor | 0.04 | E608 | 0.004 | 0.05 | ND |
| o-Dichlorobenzene | 0.6 | E624 | 0.16 | 4.2 | ND |
| p-Dichlorobenzene | 0.075 | E625 | 1.3 | 0.4 | ND |
| Pentachlorophenol | 0.001 | E625 | 0.25 | 4 | ND |
| Picloram | 0.5 | E625 | 2 | 4 | ND |
| Polychlorinated biphenyls | 0.0005 | E608 | 0.035 | 1 | ND |
| Tetrachloroethylene | 0.005 | E624 | 0.11 | 0.5 | ND |
| Toluene | 1 | E624 | 0.1 | 0.5 | 0.0039 |
| Toxaphene | 0.003 | E608 | 0.31 | 1 | ND |
| Trans-1,2-Dichloroethylene | 0.1 | E624 | 0.15 | 0.5 | ND |
| Trichloroethylene | 0.005 | E624 | 0.08 | 0.5 | ND |
| Vinyl chloride | 0.002 | E624 | 0.16 | 0.5 | ND |
| Xylenes | 10 | E624 | 0.11 | 0.5 | ND |
| Radiological testing | Standards | Analysis method | Results |
| Gross alpha particle activity (excluding radon and uranium) | 15 pCi/L | E900.0 | ND |
| Gross beta particle and photon emitter activity | 4 mrem/yr | E900.0 | ND |
| Tritium | 0.27 uCi/L | E906.0 | ND |
| Combined Ra-226 and Ra-228 activity | 5 pCi/L | A7500-RA | ND |
| Uranium | 30 ug/L | E200.8 | ND |
| Disinfectants | Standards (mg/L) | Analysis method (mg/L) | Method detection limit (mg/L) | Practical quantitation limit (mg/L) | Results (mg/L) |
| Chloramines | 4 | A4500CL | 0.1 | 0.1 | ND |
| Chlorine | 4 | A4500CL | 0.1 | 0.1 | 1.3 |
| Chlorine dioxide | 0.8 | A4500CL | 0.1 | 0.1 | ND |
| Disinfection byproducts | Standards (mg/L) | Analysis method (mg/L) | Method detection limit (mg/L) | Practical quantitation limit (mg/L) | Results (mg/L) |
| Bromate | 0.01 | E300.1 | 420 | 1000 | ND |
| Chlorite | 1 | E300.1 | 0.1 | 0.1 | ND |
| Total trihalomethanes | 0.08 | E624 | 0.14 | 0.5 | ND |
| Microbiological testing | Standards (mg/L) | Analysis method (mg/L) | Method detection limit (CFU/ 100ml) | Results (mg/L) |
| E.coli | 0 (P/A) | Colilert | 1 | Absence |
| Total coliforms | 0 (P/A) | Colilert | 1 | Absence |
| Other compounds not listed in EPA and NPDWR standards | Average values of product water, mg/L |
| TOC (total organic carbon) | 1.4 |
| Na (sodium) | 26.75 |
| NH4 (ammonium) | 2.9 |
| K (potassium) | LDL |
| Ca (calcium) | 0.9 |
| Cl (chloride) | 39.4 |
| NO2 (nitrite) | LDL |
| Br (bromide) | LDL |
| NO3 (nitrate) | LDL |
| PO4 (phosphate) | LDL |
| SO4 (sulfate) | LDL |
| Mg (magnesium) | LDL |
ND: not detected; LDL: lower than detection limit.
