This list of technologies is intended to be representative but not comprehensive. There are technologies that may be appropriate to a given application that are not listed here. Before applying a technology to any real-life situation, it is critical to test the potential water supply source for contaminants and to consult a professional water scientist or engineer.
Additionally, countries have different laws and regulations. These technologies are not warranted to be legal and appropriate in a given country.
Finally, many non-technological factors are important to consider, including community needs and preferences, mechanisms to prevent recontamination of the treated water, personal hygiene such as handwashing, and financial and other mechanisms to provide sustained and uninterrupted availability.
Coagulation-Flocculation
|
Filtration Systems
|
Membrane Processes
|
Chemical Disinfection/Oxidants
|
Adsorption and Ion Exchange Systems
|
Air Stripping Systems
|
Solar Treatment
| Conventional Coagulation- Flocculation- Sedimentation |
Dissolved Air Flotation | Flocculation- Chlorination |
Lime Softening | |
|---|---|---|---|---|
| System/Process | Coagulation- Flocculation associated with sedimentation and/or filtration |
Coagulation- Flocculation associated with sedimentation and/or filtration |
Coagulation- Flocculation associated with sedimentation and/or filtration |
Coagulation- Flocculation associated with sedimentation and/or filtration |
| Contaminant Types | Turbidity; Color; Disinfection byproduct precursor; Algae; Protozoa; Bacteria; Viruses; Iron; Calcium and magnesium; Phosphate; Selenium | Turbidity; Color; Disinfection byproduct precursor; Algae; Protozoa; Bacteria; & Viruses | Viruses; Bacteria; Parasites; Protozoa; Arsenic; and Pesticides | Turbidity; Protozoa; Bacteria; Viruses; Hardness (calcium and magnesium); Iron; Manganese; Arsenic; Selenium; Radium |
| Usage Type - centralized/ household | Centralized | Centralized | Household | Centralized |
| State of Technology | Conventional in most countries including developed ones | Accepted but rare | Emerging | Conventional |
| Relative Capital Cost-Centralized | Medium | Medium | N/A | High |
| Relative Capital Cost - Household | N/A | N/A | Low | N/A |
| Water Source | Surface water sources | Surface water sources | Surface water sources | All water sources |
| Raw Water Quality Range | Can treat wide range of water quality | Very high algae okay; high color okay; moderate turbidity | Can treat wide range of water quality | All hard waters |
| Operator Skill Level Required | Basic | Advanced | Basic | Advanced |
| Monitoring Requirements | Low | High | N/A | High |
| Relative Operating Cost - Centralized | Medium | Medium/High | N/A | High |
| Relative Operating Cost - Household | N/A | N/A | Low | N/A |
| Requires Electricity | Yes | Yes | No | Yes |
| Bag/Cartridge Filters | Biosand | Ceramic Filtration | Conventional Filtration | Diatomaceous Earth Filtration | Direct Filtration | Slow Sand Filtration | |
|---|---|---|---|---|---|---|---|
| System/Process | Filtration Systems | Filtration Systems | Filtration Systems | Filtration Systems | Filtration Systems | Filtration Systems | Filtration Systems |
| Contaminant Types | Protozoa | Turbidity; Taste and odor; Protozoa; Bacteria | Turbidity; Bacteria; Protozoa | Turbidity; Color; Disinfection byproduct precursor; Algae; Protozoa; Bacteria; Viruses; & Arsenic Iron & Manganese if used with chlorine Ammonia & Biodegradable organic matter if used without chlorine |
Turbidity; Algae; Protozoa; Bacteria; & Viruses | Turbidity; Color; Disinfection byproduct precursor (limited); Protozoa; Bacteria; Viruses; Ammonia; Iron & Manganese if used with Chlorine Ammonia & Biodegradable organic matter if used without chlorine |
Turbidity; Taste and odor; Protozoa; Bacteria; Biodegradable organic; Ammonia |
| Usage Type - centralized/ household | Household | Household | Household | Centralized | Both | Centralized | Centralized |
| State of Technology | Accepted; extremely rare | Emerging | Emerging | Conventional | Conventional for household scale | Conventional | Conventional |
| Relative Capital Cost - Centralized | N/A | N/A | N/A | High | High | High | Medium |
| Relative Capital Cost - Household | Low | Medium | Low | N/A | Medium | N/A | N/A |
| Water Source | Surface water sources | Surface water sources | Surface water sources | Surface water sources | Surface water sources | Surface water sources GW with Fe; Mn of NH3 |
Surface water sources |
| Raw Water Quality Range | Needs very high water quality | Needs high water quality | N/A | Can treat wide range of water quality | Needs very high water quality | Raw water with turbidity below ~ 10 ntu | Needs very high water quality |
| Operator Skill Level Required | Basic | Basic | Basic | Advanced | Intermediate | Advanced | Basic |
| Monitoring Requirements | Low | N/A | N/A | High | Medium | High | Low |
| Relative Operating Cost - Centralized | N/A | N/A | N/A | Medium | Medium | Medium | Low; with good raw water |
| Relative Operating Cost - Household | Low/High; depends on cycle length | Low | Low | N/A | Medium | N/A | N/A |
| Requires Electricity | No | No | No | Yes | No | Yes | No |
| Electrodialysis/Electrodialysis Reversal | Microfiltration | Nanofiltration | Reverse Osmosis | Ultrafiltration | |
|---|---|---|---|---|---|
| System/Process | Membrane Processes | Membrane Processes | Membrane Processes | Membrane Processes | Membrane Processes |
| Contaminant Types | Hardness (Calcium and Magnesium); Iron; Manganese; Arsenic; Selenium; Thallium; Fluoride; Radium; Uranium; Cations; Anions; Total dissolved solids; Nitrate; Ammonia | Turbidity; Algae; Protozoa; Bacteria | Color; Disinfection byproduct precursor; Pesticides; Hardness (calcium and magnesium); Algae; Bacteria; Protozoa; Viruses | Color; Disinfection byproduct precursor; Semivolatile compounds; Pesticides; Hardness (calcium and magnesium); Arsenic; Selenium; Thallium; Fluoride; Radium; Uranium; Cations; Anions; Total dissolved solids; Nitrate; Ammonia; salinity; Algae; Bacteria; Protozoa; Viruses | Turbidity; Algae; Protozoa; Bacteria; Viruses |
| Usage Type - centralized/ household | Centralized | Centralized | Centralized | Both | Centralized |
| State of Technology | Accepted but rare | Conventional | Conventional | Conventional | Conventional |
| Relative Capital Cost - Centralized | Very High | High | Very High | High | High |
| Relative Capital Cost - Household | N/A | N/A | N/A | High | N/A |
| Water Source | All water sources | Surface water sources | All water sources | All water sources | Surface water sources |
| Raw Water Quality Range | Requires prefiltration for surface water | Needs high water quality (or pretreatment) | All surface waters require pretreatment | All surface waters require pretreatment | Needs very high water quality (or pretreatment) |
| Operator Skill Level Required | Very Advanced | Intermediate | Very Advanced | Very Advanced | Intermediate |
| Monitoring Requirements | Very High | High | Very High | Very High | Very High |
| Relative Operating Cost - Centralized | Very High | Medium | High | Very High | Medium |
| Relative Operating Cost - Household | N/A | N/A | N/A | High | N/A |
| Requires Electricity | Yes | Yes | Yes | Yes | Yes |
| Chlorination | ClO2 | NH2Cl/Chloramines | O3 Ozonation | Ultraviolet radiation | |
|---|---|---|---|---|---|
| System/Process | Chemical Disinfection/ Oxidants | Chemical Disinfection/ Oxidants | Chemical Disinfection/ Oxidants | Chemical Disinfection/ Oxidants | Chemical Disinfection/ Oxidants |
| Contaminant Types | Bacteria; Viruses; & Iron | Protozoa; Bacteria; Viruses | Bacteria | Color; Taste and odor; Protozoa; Bacteria; Viruses; & Iron | Protozoa; Bacteria; & Viruses |
| Usage Type - centralized/ household | Both | Centralized | Centralized | Both | Both |
| State of Technology | Conventional | Accepted | Conventional | Conventional | Conventional |
| Relative Capital Cost - Centralized | Low | Low | Low | Medium | Medium |
| Relative Capital Cost - Household | Low | N/A | N/A | Medium | Medium |
| Water Source | All water sources Both primary and secondary disinfection |
All water sources Both primary and secondary disinfection |
All water sources usually only secondary disinfection |
All water sources Only primary disinfection |
All water sources Only primary disinfection |
| Raw Water Quality Range | All; but better with higher quality | All; but better with very high quality | All; but better with higher quality | All; but better with higher quality | All; but better with higher quality |
| Operator Skill Level Required | Basic | Intermediate | Basic | Advanced | Intermediate |
| Monitoring Requirements | Low | Medium | Low | High | Medium |
| Relative Operating Cost - Centralized | Low | Medium/Low | Low | Medium | Low |
| Relative Operating Cost - Household | Low | N/A | N/A | Medium | Low |
| Requires Electricity | No | Yes | Yes | Yes | Yes |
| Activated Alumina | Granular Activated Carbon (GAC) | Ion Exchange | Powdered Activated Carbon (PAC) | |
|---|---|---|---|---|
| System/Process | Adsorption and Ion Exchange Systems | Adsorption and Ion Exchange Systems | Adsorption and Ion Exchange Systems | Adsorption and Ion Exchange Systems |
| Contaminant Types | Arsenic; Selenium; Thallium; Fluoride | Color; Disinfection byproduct precursors; Taste and odor; Protozoa; Bacteria; Viruses; Volatile organic compounds (VOCs); Semivolatile compounds; Pesticides; & Biodegradable organic matter | Catoin Resins - Hardness (Calcium and Magnesium); Fluoride; Radium; Ammonia Anion Resins - Nitrate; Perchlorate; Arsenic | Color; Disinfection byproduct precursors; Taste and odor; Volatile organic compounds (VOCs); Semivolatile compounds; Pesticides; Biodegradable organic matter |
| Usage Type - centralized/ household | Both | Both | Both | Centralized |
| State of Technology | Accepted but rate | Conventional | Conventional | Conventional |
| Relative Capital Cost - Centralized | High | High | High | Medium |
| Relative Capital Cost - Household | Medium | Medium | Medium | N/A |
| Water Source | Ground water | All water sources | Ground water | Surface Water |
| Raw Water Quality Range | All ground waters | Surface water may require prefiltration | All ground waters | All surface waters |
| Operator Skill Level Required | Advanced | Intermediate | Intermediate | Basic |
| Monitoring Requirements | High | High | High | Low |
| Relative Operating Cost - Centralized | Very High | High to Very High | High | Medium/High |
| Relative Operating Cost - Household | High | High | High | N/A |
| Requires Electricity | No | No | Yes | Yes |
| Aeration: Diffused air | Mechanical Aeration | Packed Tower Aeration | Tray Aerators | |
|---|---|---|---|---|
| System/Process | Air Stripping Systems | Air Stripping Systems | Air Stripping Systems | Air Stripping Systems |
| Contaminant Types | Taste and odor; Volatile organic compounds; Iron; Radon; Sulfides | Taste and odor; Volatile organic compounds; Iron; Radon; Sulfides | Taste and odor; Volatile organic compounds; Iron; Radon; Sulfides | Taste and odor; Volatile organic compounds; Iron; Radon; Sulfides |
| Usage Type - centralized/ household | Both | Centralized | Both | Both |
| State of Technology | Conventional | Conventional | Conventional | Conventional |
| Relative Capital Cost - Centralized | Low | Low | Low | Low |
| Relative Capital Cost - Household | Medium | N/A | Medium | Medium |
| Water Source | Ground water | Ground water | Ground water | Ground water |
| Raw Water Quality Range | All ground waters | All ground waters | All ground waters | All ground waters |
| Operator Skill Level Required | Basic | Basic | Intermediate | Basic |
| Monitoring Requirements | Low | Low | Low | Low |
| Relative Operating Cost - Centralized | Low | Low | Low | Low |
| Relative Operating Cost - Household | Low | N/A | Medium | Low |
| Requires Electricity | Yes | Yes | Yes | No |
| Solar Disinfection | Solar Distillation | |
|---|---|---|
| System/Process | Solar Treatment | Solar Treatment |
| Contaminant Types | Viruses; Bacteria; Parasites; Protozoa | Color; Disinfection; Protozoa; Bacteria; Viruses; Semivolatile compounds; Pesticides; Hardness (Calcium and Magnesium); Arsenic; Selenium; Thallium; Fluoride; Radium; Uranium; Cations; Anions; Total dissolved solids; Nitrate; Ammonia; salinity |
| Usage Type - centralized/ household | Household | Household |
| State of Technology | Emerging | Emerging |
| Relative Capital Cost - Centralized | N/A | N/A |
| Relative Capital Cost - Household | Low | Medium |
| Water Source | All water sources | All water sources |
| Raw Water Quality Range | Needs high water quality | Can treat wide range of water quality |
| Operator Skill Level Required | Basic | Basic |
| Monitoring Requirements | N/A | Low |
| Relative Operating Cost - Centralized | N/A | N/A |
| Relative Operating Cost - Household | Low | Low |
| Requires Electricity | No | No |
Coagulation-Flocculation
|
Filtration Systems
|
Membrane Processes
|
Chemical Disinfection/Oxidants
|
Adsorption and Ion Exchange Systems
|
Air Stripping Systems
|
Solar Treatment