A story from the field: the classroom learners wait for every Sunday

Ann teaches at a sub-district non-formal education center, known in Thailand as a กศน. classroom, in Bang Rakam district, Phitsanulok. Her classroom is a modest single-story building shared with the community. Inside are folding tables, plastic chairs, a whiteboard, six donated computers and a reading corner that villagers have built up together over many years. Every Sunday, working adults come to finish their secondary education: rice farmers, market vendors, factory workers on their day off. A group of older residents also comes to practice reading and writing and to learn how to use their smartphones to call their grandchildren and check the news.

Bang Rakam is low-lying land, and people here are used to seasonal flooding. In the 2026 floods, however, the water came higher than anyone remembered and stayed for almost two weeks. Ann and a few volunteers managed to lift the computers onto tables before the water arrived, but the books on the lowest shelves, the learners' portfolios and boxes of teaching materials were almost all submerged.

When the water finally drained away, Ann opened the classroom door and had to step back. A heavy smell of damp and mud poured out of the room. A long brown waterline ran across every wall, and below it gray and black spots of mold had begun to spread. Even the books on the upper shelves, which had never touched the water, smelled musty, and small mold spots were appearing along the edges of the pages. The steel table legs were starting to rust, and dried mud clung stubbornly to every plastic chair.

What worried Ann most was her learners. "Several of the aunties have allergies, and one of the uncles has asthma. If we reopen and the whole room starts coughing, they will not want to come back, and it took so much effort to persuade them to study in the first place." On top of that, end-of-term exams were approaching. Ann needed a recovery method that genuinely worked and was fast enough to keep the term on track. This article brings together practical guidance for learning centers, adult classrooms and community reading corners after a flood.

Why adult classrooms need extra care after a flood

Many learners are older or live with chronic conditions. Unlike a typical children's classroom, a non-formal education class brings together people of every age. Some have allergies, asthma or long-term lung conditions. Mold spores and dust from dried mud can trigger their symptoms. Any learner with a cough, breathing difficulty or fever should see a doctor. This article offers general guidance on cleaning and disinfecting buildings, not medical advice.

The room is only open on certain days. A classroom used once or twice a week usually stays shut the rest of the time. Moisture builds up quietly with no one around to open the windows, so mold grows faster than people expect. By the time the next class arrives, a room that looked dry on Monday can smell musty again.

Books and paper feed mold. Reading corners, portfolios, worksheets and cardboard boxes absorb moisture very easily. When they stay damp, mold grows and releases spores, so the musty smell lingers long after the floor is dry. A single moldy shelf can slowly spread spores to every other book in the room.

Rural floodwater carries contamination. Water that has flowed across rice fields, animal pens and septic tanks may carry bacteria such as E. coli and Leptospira, the cause of leptospirosis, which is common in rural areas during floods. These germs remain on floors, table legs and the lower part of walls after the water has gone.

The classroom belongs to the whole community. Besides lessons, the room hosts village meetings, vocational training and children who come to read during school holidays. If it is not properly cleaned, the impact reaches far beyond the enrolled learners.

What teachers and centers have to deal with

Learners' health. People who react easily may sneeze, suffer a blocked nose or feel tightness in the chest after several hours in a moldy room. Some learners wade through floodwater to reach class and may have small wounds on their feet, which can become infected from floors that are not yet clean.

Continuity of learning. Working adults have very little time to study. Every week the classroom stays closed is a week in which someone might drop out for good. With exams approaching, the pressure only increases. For many adult learners, finishing secondary school is the key to a better job or a promotion, so a lost term has real consequences.

Property and learning materials. Donated computers, books collected over many years and teaching aids that teachers made by hand are all hard to replace. Letting mold spread to items that survived the flood means suffering the damage twice.

Confidence of learners and the community. For many adults, deciding to return to education takes real courage. If the first day back greets them with a musty smell, they may feel nobody cares. A fresh, clean classroom, on the other hand, tells them they are valued and that their effort is worth supporting.

Why the usual cleaning methods are not enough

Washing the floor and locking the room until class day. Washing removes the mud, but if the room is closed for a whole week, moisture from the walls and furniture brings the musty smell straight back and lets mold keep growing.

Wiping books with a damp cloth and cleaner. Cleaning the cover helps a little, but mold between the pages stays put, and some cleaning products can damage paper further.

Strong bleach in a closed room. Bleach fumes irritate the airways, which is a poor choice for a room where older learners sit for hours. Bleach must never be mixed with toilet cleaners or ammonia.

Air fresheners or bags of charcoal. These can reduce odor slightly in a small room, but they do not deal with the cause: mold and moisture trapped in walls and objects.

Painting over the walls straight away. If the wall is still damp and moldy, new paint will blister and the mold will reappear within weeks, wasting money that a small center can rarely spare.

The solution: ozone treatment combined with Chemgene HLD4H disinfection

World Health Disinfection (WHD) provides ozone treatment and disinfection fogging for buildings recovering from floods, including classrooms, meeting rooms and community libraries. The two methods complement each other.

Ozone treatment. Ozone is a gas that spreads throughout a room, reaching the gaps between bookshelves, the space under tables and the corners of the ceiling. It helps deal with mold spores and breaks down odor molecules trapped in walls, curtains and paper. Our team uses the Master Ozone Generator and adjusts the dose and duration to the size of the room.

ULV disinfection fogging. We apply Chemgene HLD4H as a fine mist across floors, lower walls, table legs, chairs, door handles and washrooms, targeting the germs that floodwater leaves behind.

Ozone safety. No people, pets or plants may be in the room during treatment. Our team closes the room, posts no-entry signs and ventilates until it is safe before teachers and learners go back in. Computers, projectors and other electronics are covered or moved out, and the ozone dose is carefully controlled. Old books or documents with historical value should be assessed by a document conservation specialist before any treatment.

Step by step: restoring a non-formal education classroom

1. Survey with the teacher. We check how high the water rose, where mold has appeared, where the smell is strongest and which items need a decision, such as books, portfolios and electrical equipment.

2. Sort books and documents. Books that were soaked until they turned to pulp or stuck together in a block are rarely recoverable and are usually best discarded. Books that are only slightly damp should be fanned open and dried in a shaded, airy place rather than in harsh sun, which makes paper brittle. Important learner portfolios should be photographed or scanned first.

3. Clear the mud and have an electrician check the wiring. Shovel out the mud, wash the floor and wipe down tables and chairs. Helpers should wear rubber boots, rubber gloves and a mask. Before switching on lights or plugging in computers, always have an electrician inspect the system.

4. Disinfection fogging. Fine mist is applied throughout the classroom, washroom and corridor, with extra attention to frequently touched surfaces.

5. Ozone treatment. The room is closed, computers and electrical equipment are covered, and ozone is applied for a time suited to the room size and the strength of the odor.

6. Ventilation. Doors and windows are opened and fans switched on until the ozone smell has faded and our team confirms the room is ready to use.

7. Re-check. We return to check wall moisture and odor. If the walls are still damp, we advise waiting before painting and schedule a spot re-treatment if needed.

Checklist before welcoming learners back

• No musty smell when the door is first opened in the morning.
• No new mold spots on walls or in corners.
• Tables and chairs clean and free of mud; rusty table legs sanded or painted with anti-rust paint.
• The reading corner holds only books that are completely dry and mold-free, placed slightly away from the wall.
• Computers checked by a technician before being switched on.
• Washroom cleaned and disinfected, with soap available.
• A schedule for opening windows on days without classes.

10 reasons community classrooms choose ozone treatment and disinfection

1. Ozone treatment reaches the gaps between bookshelves and ceiling corners that no cloth can.
2. It reduces the musty smell that makes learners reluctant to sit through a full lesson.
3. Disinfection fogging covers floors, lower walls, tables and chairs evenly.
4. We use Chemgene HLD4H, a disinfectant designed for surface disinfection work.
5. Less need for strong bleach in a room where older learners sit for hours.
6. It helps stop mold spreading to books and materials that survived the flood.
7. Clear safety steps: electronics covered, room sealed, then thoroughly ventilated.
8. Classes can resume in time for exams.
9. A fresh classroom shows learners they are cared for, encouraging them to continue.
10. It can be combined with our mosquito spraying service around the building while water still stands, and our dust mite removal service for cushions and rugs.

Before and after restoration

In the teacher's words

"On the day we reopened, the auntie with allergies walked in and smiled. She said the room did not smell anymore and she could sit and study all day. I was so happy, because my biggest fear was that the flood would make our learners disappear."

— Ann, non-formal education teacher in Bang Rakam district (an illustrative scenario from the field)

Saving the community reading corner

For many villages, the reading corner in the learning center is the only public collection of books within easy reach. It deserves a careful plan rather than a hasty clear-out. Start by separating books into three groups: those that are clearly ruined, those that are damp but intact, and those that stayed dry. Remove the ruined books from the building as soon as possible, because they are the main source of spores.

Damp but intact books should be stood upright with the pages fanned open, in a shaded spot with good airflow. A fan pointing past the books, not directly into them, helps moisture escape without blowing spores around the room. Turning the books every day speeds up drying. Avoid stacking them until they are fully dry, as stacks trap moisture in the middle.

Books that stayed dry still need attention, because they have been sitting in humid air with moldy neighbors. Once the room has been disinfected and treated with ozone, check them again for smell and spots before returning them to the shelves. Keep the bottom shelf empty for a while, or use it only for plastic boxes, so the collection is never the first thing the next flood reaches.

If the corner contains rare books, local history records, temple manuscripts or photographs with community value, do not treat them yourself. Contact a document conservation specialist, who can advise on freezing, drying and stabilizing fragile materials.

A realistic reopening timeline for a small learning center

Teachers often ask how to fit the recovery around the teaching calendar. Every building is different, but the following sequence works well for a single classroom with a small washroom and reading corner, and it can be adjusted once our team has seen the site.

Days one and two after the water recedes. Open every door and window during daylight. Photograph the damage for any report you need to send to your district office or to donors. Shovel out the mud, wash the floor and move all furniture away from the walls. Sort the books into ruined, damp and dry groups, and take the ruined items out of the building. Ask an electrician to inspect the wiring before anything is switched on.

Days three to five. Continue drying. Fan the damp books open in the shade and turn them every day. Wipe tables and chairs, and treat rusty table legs. This is a good time to contact us for a survey, so that disinfection and ozone treatment can be scheduled as soon as the bulk of the moisture is gone.

Treatment day. Our team disinfects the classroom, washroom and corridor, covers the computers and electronics, and carries out the ozone treatment with the building empty. After ventilation, the teacher is told when it is safe to go back in.

The following days. Return the dry, clean books to the upper shelves, set up the furniture again and keep the windows open as much as possible. If the walls are still damp, wait before painting. When the room passes the checklist above, invite learners back, perhaps starting with a short session so that everyone can see the room has been looked after.

Explaining this timeline to learners through the class chat group or a notice at the village hall helps them plan their own schedules and reassures them that the term will continue. Many adult learners juggle work and family duties, and knowing the date in advance makes it far more likely that they will return.

Tips for classrooms in areas that flood every year

Keep things high as a habit. Use tall shelving, store books and portfolios on the upper levels, and keep lidded plastic boxes ready to move important items when a flood warning is issued.

Ventilate even on days without classes. Ask a volunteer or community leader to open the windows two or three times a week during the weeks after the water recedes.

Wipe touch points before each lesson. Use Chemgene HLD4H spray on desks, door handles and computer keyboards before each class.

Check the books every month. If you find a book with new mold spots, remove it immediately so it does not spread to the rest of the collection.

Turn the experience into a lesson. A non-formal education classroom is a learning space for the whole community. Teachers can use the flood as a real-life lesson on handwashing, caring for wounds and recognizing the warning signs of leptospirosis, drawing on information from Thailand's Department of Disease Control. Adult learners often share what they learn with their families, multiplying the benefit.

Frequently asked questions

Can slightly moldy books be used again after ozone treatment?
For books that are already dry with only light mold, ozone treatment helps reduce odor and spores. Books that have turned to pulp or stuck together should usually be discarded. Rare books or important documents should be referred to a conservation specialist.

Do the computers need to be moved out?
Our team will advise whether to cover them or move them, and will control the ozone dose. Any computer that was submerged should be checked by a technician before it is switched on.

How long before the classroom can reopen?
It depends on room size and how damp the walls are. In many cases fogging and ozone treatment can be completed in a single day, followed by ventilation before use. We will give an estimated timeline during the survey.

Should the center's washroom be treated too?
Yes, we recommend it. The washroom is where floodwater usually leaves the most sewage contamination.

Do we need to do this every year?
If water enters the building and stays for a long time, restoration is advisable each time. Lifting belongings out of reach beforehand greatly reduces both damage and cost.

Can learners help with the clean-up?
Many adult learners are happy to help, and their help is valuable for moving furniture, sorting books and washing mud from floors. Make sure everyone wears rubber boots, gloves and a mask, washes their hands well afterwards, and keeps any cuts covered. Learners with asthma, allergies or open wounds are better given tasks outside the damp room, such as checking dry books in the open air.

Which areas do you serve?
We serve Bang Rakam, Mueang Phitsanulok, Phrom Phiram, Bang Krathum and nearby districts. Contact us on LINE @whd268 to check availability.

Get your classroom ready to welcome learners again

Book a survey for a flooded learning center, community classroom or library in Bang Rakam and nearby areas.

Book Ozone Treatment – Click Here

View Disinfection Service – Click Here

Call 065-556-6294 · LINE @whd268 · worldhealthdisinfection@gmail.com

Related links

• Ozone deodorizing and chemical residue removal
• Residential ozone disinfection
• Master Ozone Generator
• All articles
• External sources: WHO: Floods and health and Department of Health, Thailand