At pains to stress
07/28/11 15:29 Filed in: Caution
1) Chlorine use not recommended . . .
Since chlorine-based disinfectants react with natural organic material, exerting a chlorine demand (precursor to the emergence of chlorination by-products, i.e., carcinogenic trihalomethanes), the use of Moringa oleifera crude extract in conjunction with primitive application of chlorine-based disinfectants is not recommended.”
2) Second Disinfection Process Recommended . . .
“The relationship between infectious turbidity dosage (pathogens attached to suspended particles) and host susceptibility, especially among the malnourished and vulnerable (children under 5), is a complicated and critical factor that contributes to the likelihood of acquiring a waterborne illness, i.e., diarrhea, a leading cause of extreme child morbidity and mortality in the developing world. Rudimentary Moringa oleifera usage can produce potable water of higher quality than the original source, but is unable to guarantee 100% complete viral and/or bacterial elimination immediately after treatment or storage. If at all possible, an additional second disinfection (excluding chlorine) process is recommended.”
3) Not effective at low turbidity . . .
The performance efficiency of Moringa oleifera is better with moderately to heavily turbid water. It is not an effective coagulant for low-turbidity (<50 NTU) water. The reason, basically if you try to treat low-turbidity water you’ll potentially end up with more organics in the water than you originally started without any performance benefits. See also . . . Unique Disadvantages of Chlorine.
Since chlorine-based disinfectants react with natural organic material, exerting a chlorine demand (precursor to the emergence of chlorination by-products, i.e., carcinogenic trihalomethanes), the use of Moringa oleifera crude extract in conjunction with primitive application of chlorine-based disinfectants is not recommended.”
2) Second Disinfection Process Recommended . . .
“The relationship between infectious turbidity dosage (pathogens attached to suspended particles) and host susceptibility, especially among the malnourished and vulnerable (children under 5), is a complicated and critical factor that contributes to the likelihood of acquiring a waterborne illness, i.e., diarrhea, a leading cause of extreme child morbidity and mortality in the developing world. Rudimentary Moringa oleifera usage can produce potable water of higher quality than the original source, but is unable to guarantee 100% complete viral and/or bacterial elimination immediately after treatment or storage. If at all possible, an additional second disinfection (excluding chlorine) process is recommended.”
The performance efficiency of Moringa oleifera is better with moderately to heavily turbid water. It is not an effective coagulant for low-turbidity (<50 NTU) water. The reason, basically if you try to treat low-turbidity water you’ll potentially end up with more organics in the water than you originally started without any performance benefits. See also . . . Unique Disadvantages of Chlorine.
Best strategy: multi-barrier
07/28/11 15:05 Filed in: Multi-barrier
"I was intrigued by the efficacy of Moringa seeds in removing water turbidity. I was wondering if the quality of water treated by Moringa seeds could further be improved by application of other purification techniques say filtration?"
Response
Absolutely, a multi-barrier intervention is the best strategy for providing the safest quality of drinking water.
Education and training, emphasizing environmental awareness, hygiene, and sanitation are thus first necessities. Reduction of excessive turbidity and particulates by settlement or pre-filtration or coagulation / flocculation establishes a second barrier. Removal of parasites, protozoal cyst, bacterial pathogens, and in some situations removal of chemical contaminants (e.g. arsenic) by filtration is the third barrier. The fourth and final barrier, safe storage in a closed container and providing a disinfectant (e.g., SODIS) are all key aspects to strengthen local capacity to carry out sustainable community-based primary health care. -- Michael
Unique Disadvantages of Chlorine
07/12/11 19:56 Filed in: Chlorination
Inquiry
Interesting stuff, but another really easy way to make water safe is with a simple drop of chlorine. I actually do some work with the American Chemistry Council and we’ve been working with municipalities on chlorinating water supplies. Most major towns and cities have been chlorinating their drinking water for 100 years. We’re now working on bringing this simple and safe method to more rural and developing areas.
Response
Each point-of-use water treatment technology has unique strengths. Chlorination is a well-proven technique, but, as does all point-of-use treatment technologies it also has it’s own unique disadvantages.
For instance, waterborne pathogens such as cryptosporidium and giardia have high resistance to chemical disinfectants such as chlorine, but are removed by sand filtration. There are also technical and logistical issues of chlorine effectiveness across different ranges of turbidity levels caused by seasonal change, i.e., monsoons.
Also, the serious question of chlorine’s role in the formation of harmful halogenated organic compounds (halomethanes) in drinking water still remains.
In addition, it’s well established that people dislike the strong odor and disagreeable taste associated with free chlorine.
Most importantly, due to the necessity to continuously repurchase a consumable product, at-risk households will abandon treating water when financial resources are unavailable.
All are critical factors that cause considerable discontinuation – therefore, as evidenced within various studies, chlorination as a stand alone intervention within developing countries hasn’t been able to achieve scalability or long-term sustainability. -- Michael
Interesting stuff, but another really easy way to make water safe is with a simple drop of chlorine. I actually do some work with the American Chemistry Council and we’ve been working with municipalities on chlorinating water supplies. Most major towns and cities have been chlorinating their drinking water for 100 years. We’re now working on bringing this simple and safe method to more rural and developing areas.
Response
Each point-of-use water treatment technology has unique strengths. Chlorination is a well-proven technique, but, as does all point-of-use treatment technologies it also has it’s own unique disadvantages.
For instance, waterborne pathogens such as cryptosporidium and giardia have high resistance to chemical disinfectants such as chlorine, but are removed by sand filtration. There are also technical and logistical issues of chlorine effectiveness across different ranges of turbidity levels caused by seasonal change, i.e., monsoons.
Also, the serious question of chlorine’s role in the formation of harmful halogenated organic compounds (halomethanes) in drinking water still remains.
In addition, it’s well established that people dislike the strong odor and disagreeable taste associated with free chlorine.
Most importantly, due to the necessity to continuously repurchase a consumable product, at-risk households will abandon treating water when financial resources are unavailable.
All are critical factors that cause considerable discontinuation – therefore, as evidenced within various studies, chlorination as a stand alone intervention within developing countries hasn’t been able to achieve scalability or long-term sustainability. -- Michael
