Floods have a significant negative impact on human health and the living environment. After floods, various diseases such as cholera, dysentery, and typhoid often occur, primarily caused by environmental contamination and polluted water sources. Without proper measures, large-scale outbreaks may arise.
A/ Water Treatment and Environmental Sanitation Before Floods
1. For Water Sources
- Hand-dug wells: Cover the well’s mouth tightly with thick, non-perforated plastic and secure it with rubber bands.
- Bore wells: Use thick, non-perforated plastic to seal the tap and the bore well head, securing it with rubber bands.
2. For Toilets
- Two-chamber latrines: Remove all waste, dig a deep pit at least 10 meters away from drinking water sources, treat with lime powder or ash, then cover it thoroughly with soil. Before sealing the pit, add lime powder or ash.
- Septic toilets or water-flushed toilets: Prepare a tight cover for the toilet hole.
- Latrines with vent pipes: Cover the surface of the feces with lime powder or ash, then seal it tightly with soil.
3. Livestock Pens
Collect animal waste and place it in a pit at least 10 meters away from drinking water sources, then sprinkle lime powder or ash over the entire surface and cover it thoroughly with soil.
After floods, various diseases such as cholera, dysentery, and typhoid often occur.
B/ Treatment of Domestic Water During Flood Season
During the flood season, if wells are submerged and there is no stored water, floodwater must be treated for domestic use in two steps:
Step 1: Clarify Water
Dissolve 1 gram of alum (approximately the size of a large corn kernel) in 20 liters of water, stir, and wait for 30 minutes until the water settles and becomes clear. If alum is unavailable, use clean cloth to filter the water.
Step 2: Disinfect Water
After clarifying with chemicals, use Chloramine: dissolve 1 tablet of Chloramine T or B (250 mg) in 25 liters of water. Stir well until the chemical is fully dissolved; it should be used after 30 minutes.
* In emergency situations without alum for clarification, increase the amount of Chloramine B:
- If the water is moderately turbid: dissolve 15-20 mg of Chloramine B in 1 liter of water, or 15-20 grams of Chloramine B (approximately 1.5 – 2 teaspoons) in 1 cubic meter of water.
- If the water is very turbid: dissolve 20-50 mg of Chloramine B in 1 liter of water, or 20-50 grams of Chloramine B (approximately 2 – 5 teaspoons) in 1 cubic meter of water.
Note: Do not carry out clarification and disinfection simultaneously.
C/ Water Treatment and Environmental Sanitation After Floods
1. Environmental Treatment
- As the water recedes, mobilize the community to clean the environment accordingly. If not done promptly, it will be difficult to remove silt from homes, yards, and pathways.
- Once the water has fully receded, the environment may be heavily contaminated, emitting foul odors from decaying animals, insects, and plants. Therefore, it is necessary to clear drains, fill stagnant water pools, bury dead animals, and disinfect.
On Handling Dead Animals
- Survey and estimate the number of dead animals that need to be handled.
- Select a location to bury dead animals at least 50 meters away from water sources. Dig a burial pit at least 0.8 meters deep, add 3-5 kg of lime powder or spray with high-concentration Chloramine B, then cover tightly with soil and secure it to prevent animals from digging it up.
- Disinfect the area where dead animals were found: After burying the animals, spray disinfectant or sprinkle lime powder in the area. If lime or disinfectants are unavailable, burn dry waste in the area where the animals were found. Check daily to ensure the burial site has not been disturbed by animals or rodents. If foul odors or digging are detected, cover the area immediately.
Clean the house, dry clothes, and avoid hanging damp clothes in areas that may attract mosquitoes.
Choose a burial site for dead animals at least 50 meters away from water sources.
2. Treatment of Domestic Water
Consists of 4 steps:
Clarify water with alum ———> Disinfect water with Chloramine ———-> Boil ———-> Drink.
a. For Open Wells: Follow these 3 steps:
* Step 1: Clean the Well:
- Clean the walls and bottom of the well, and clear floodwater around the well.
- Before clarifying and disinfecting, clean the well, removing all mud and washing the walls.
* Step 2: Clarification Method:
- Use alum at a dosage of 50 grams per cubic meter of water (1 gram of alum is approximately the size of a large corn kernel); if the water is very turbid, increase the alum dosage but not exceeding 100 grams per cubic meter.
- Finely grind and completely dissolve the alum in a container.
- Pour the alum water into a scoop and vigorously lower it into the well, then lift the scoop up and down about 10 times. Wait for 30 minutes before disinfecting the water.
* Step 3: Well Water Disinfection:
- Estimate the volume of water in the well in cubic meters (1 barrel is equivalent to 1 cubic meter); for every 1 cubic meter, dissolve 10 – 20 grams of Chloramine B, equivalent to 1 to 2 tablespoons (depending on the water turbidity).
- Dip a scoop of water.
- Dissolve the aforementioned chemical in the water, stirring well until it is completely mixed.
- Vigorously lower the scoop into the well, lifting it up and down about 10 times.
- After 30 minutes, scoop some water and smell for a chlorine odor; if detectable, the water is ready for use. If no chlorine smell is present, add about 1/3 tablespoon of Chloramine B powder, stir well, and pour into the well until a chlorine odor is detected.
- Use this well water to pour over the well walls for disinfection.
- Only use the water after 30 minutes (ensure residual chlorine levels are between 0.3 – 0.5 mg/liter).
(If too much Chloramine B is accidentally added, wait until the chlorine smell dissipates before using).
Note:
- Do not disinfect simultaneously while clarifying.
- If there is a chlorine smell after disinfection, it indicates successful disinfection.
- Water that has been clarified and disinfected must still be boiled before drinking.
Water that has been clarified and disinfected must still be boiled before drinking.
b. For Bore Wells:
- Remove the rubber and plastic covering the bore well.
- Scrub the tap, head, and bottom of the bore well.
- Clear the drainage around the well.
- Pump out the turbid water, then continue pumping for another 15 minutes to discard the water before using.
Method of Disinfecting Drinking Water with Chemicals
3. Preventing Diseases After Floods
a. Preventing Conjunctivitis:
- Do not wash or bathe in dirty water.
- Apply 0.4% Chloramphenicol eye drops for all individuals at risk of exposure to contaminated water.
- Avoid sharing bowls or towels.
b. Preventing Skin Diseases
- Avoid bathing, washing, or doing laundry with dirty water.
- Avoid wearing damp clothes.
- Limit wading into dirty water; if necessary, wash immediately with clean water and dry off, especially between toes and fingers, then apply antiseptic.
c. Preventing Diarrheal Diseases, Cholera, Dysentery, Typhoid, Dengue Fever, Malaria, etc. by:
- Eating cooked food, drinking boiled water, and avoiding raw vegetables unless washed with disinfected water.
- Sleeping under mosquito nets.
- Eliminating stagnant water pools, as they are breeding grounds for mosquitoes.
- Actively exterminating flies and mosquitoes, maintaining sanitation in the community, and clearing drainage systems…
d. Preventing Cold and Respiratory Diseases
Humid weather and abundant rainfall also increase the risk of respiratory diseases, with flu and colds being the most common. These respiratory diseases are often highly contagious, leading to outbreaks and complicating treatment.
To protect themselves, individuals need to maintain personal hygiene, limit exposure to sources of infection, wash hands frequently, and keep living and working environments clean. If symptoms of flu appear, seek medical attention promptly and isolate to prevent spreading to others.
e. Joint Diseases
Unpredictable weather after floods, sudden rain and sunshine, and cold, humid air can lead to joint pain and muscle stiffness, particularly in the hip, knee, shoulder, arms, and lower back. Joints may swell, making movement difficult.
Engaging in sports appropriate to one’s physical condition is particularly effective in relieving pain. Additionally, maintaining a balanced diet rich in vitamins C and E, calcium, and hydration helps keep joints lubricated.
In addition to disease prevention efforts by the general public, healthcare facilities must ensure adequate manpower, medication, equipment, and necessary infrastructure to provide timely emergency care and treatment for patients. Upon detecting an outbreak, swift treatment for affected individuals is essential to prevent the spread and escalation of the disease.
The above are measures for water management and environmental sanitation before, during, and after floods. We hope that everyone pays attention to these practices to protect the health of themselves, their families, and the community.
