A Story From the Field: Khru Wilaiwan and the Bottom Shelf

Khru Wilaiwan is the librarian at an extended-opportunity primary school in Si Prachan district, Suphan Buri. The school library sits on the ground floor of the older classroom building, right next to the computer room run by her colleague Khru Thanakorn. These two rooms are the children's favorite places in the whole school. At lunchtime, students crowd in to read illustrated science comics, finish homework at the long tables and queue for a turn on the computers to research their reports. For many of them, the school library is the only place they can borrow books, and the computer room is the only place they can use a computer at all.

This year, water from the Tha Chin River and its tributaries spread across the area and the school had to close. The ground floor flooded to a little more than a hand's span. Teachers and the caretaker lifted as many books and computers as they could onto higher shelves and desks, but there was no time to empty the bottom row of shelves. When the water drained away, Khru Wilaiwan opened the library door and was hit by the smell of damp, stale paper mixed with mud. The picture books and children's encyclopedias on the lowest shelf had swollen into waves. Some had fused together into solid blocks. Their covers were dotted with black and green mold. The carpet in the reading corner was soaked and sour. And on the wall behind the shelves, a long band of mold had spread along the height of the waterline.

Next door, Khru Thanakorn sat looking at the computer desks, their legs crusted with mud. Most of the machines had been lifted onto the desks in time, but the power strips and cables that had been lying on the floor had been underwater. The room smelled heavily of damp, and when he tried the air conditioner, it blew out a foul, musty smell. He asked the question many schools ask after a flood: in a room full of computers and books, can you use ozone or disinfection fogging at all, and will it damage the equipment?

The school director wanted a clear answer quickly. The new term was only a few weeks away, parents were already asking whether the building was safe, and the school could not afford to lose either the books or the computers. What the two teachers needed was not just a cleaning crew, but a plan that treated the rooms properly while protecting everything inside them. That is the kind of job the WHD team is often called in for after a flood.

Why Libraries and Computer Rooms Need Different Care From Ordinary Classrooms

A normal classroom has desks, chairs and a whiteboard, all of which are fairly easy to wash and disinfect. Libraries and computer rooms have features that make restoration much more complicated:

• Paper is food for mold. Books, magazines and files absorb a great deal of moisture. After several damp days, mold grows on covers, works its way into the paper and releases spores into the room.
• Shelves against the wall. The space behind a bookcase is a dead pocket with almost no air movement. Moisture lingers there for a long time, and it is often where mold grows thickest without anyone noticing.
• Electronic equipment. Computers, monitors, printers and routers should not be sprayed directly with liquid or exposed to wet mist, and some rubber and plastic components are sensitive to high concentrations of ozone.
• The electrical system. Power strips, cables and outlets that were underwater carry a risk of current leakage and short circuits. They must be checked by an electrician before anything is switched on.
• Closed, air-conditioned rooms. Both rooms are usually kept closed to keep out dust and heat, so musty odors and mold spores circulate inside rather than escaping.

The people using these rooms are children, who sit inside for long periods, handle the books closely, open them near their faces and pass them from hand to hand. Some already have allergies or asthma. If the room still holds mold and a musty smell, children may cough, sneeze, get itchy eyes or have allergy flare-ups, and parents will understandably worry about sending them into the library.

The Damage Goes Beyond the Smell: Learning, Budgets and Time

In small district schools, libraries and computer rooms are usually built up over many years from tight budgets and accumulated donations. Some book collections came from donation drives. Some computers were gifts from alumni. If mold is allowed to creep from the bottom shelves up to the higher ones, the damage grows every day, and replacing what is lost can take a long time.

For learning, the weeks after the water recedes are exactly when teachers are rushing to make up lost lessons. The library and computer room are key tools for research and assignments. If these two rooms stay closed for several more weeks, the students hit hardest are the ones who have no books or computers at home. A well-planned restoration therefore does more than clean a room. It helps narrow the learning gap that disasters tend to widen.

There is also the question of staff time. A librarian who spends three weeks sorting and drying books by hand, without a clear plan, is a librarian who is not running reading programs, helping struggling readers or supporting teachers. Getting expert help with the environment lets school staff focus on the work only they can do.

What Schools Usually Do, and Why It Doesn't Finish the Job

• Drying wet books in strong sunlight. Harsh sun makes paper brittle, warps covers and fades colors. If the book is not dried all the way through, mold returns once it goes back on the shelf.
• Spraying bleach on the shelves. Chlorine stains and yellows paper, its fumes bother children, and it should never be used near electronics.
• Switching computers on to test them straight away. Equipment with moisture still inside, or cables that were submerged, can short-circuit and be permanently damaged.
• Putting out moisture absorbers or charcoal. These help a little inside a small cabinet but are not enough for a whole room, and they do nothing about mold that is already growing.
• Spraying air freshener. It covers the smell for a while, but the musty odor of damp paper comes back within days.

Rooms like these need a precise, controlled approach: disinfect the surfaces that should be disinfected, deal with odors and spores in the air, and protect the books and equipment at the same time.

The Solution: Controlled Ozone Plus Targeted Fogging, With Equipment Covered First

The WHD team uses its ozone treatment service to tackle the musty odors and airborne mold spores in the library and computer room, setting the ozone dose and duration to suit the size of the room and what is inside it. Floors, walls, desks, desk legs and shelf frames are treated with the disinfection fogging service using CHEMGENE HLD4H, while avoiding spraying directly onto books or electronic equipment.

Step-by-Step Process for Libraries and Computer Rooms

1. Survey with the teachers in charge. The team looks at how high the water reached, where mold has appeared, which shelves were affected and what equipment is in the computer room.
2. Electrical check first. The team advises the school to have an electrician inspect outlets, cables and power strips that were submerged before any power is used in the room. Equipment that was underwater should be checked by a computer technician rather than switched on by staff.
3. Sorting the books. Books are divided into three groups: dry books; slightly damp books that can be air-dried in the shade; and books that are pulped or heavily moldy, which should be written off according to the school's asset regulations.
4. Cleaning and fogging. Mud is washed from floors and desk legs, soaked carpets are removed, and then Chemgene HLD4H is fogged over floors, walls, shelf frames and desks. Keyboards and mice are wiped with a cloth that has been dampened with the solution and wrung out well.
5. Covering equipment and controlled ozone treatment. Computers, monitors, printers and network devices are covered with fabric covers or plastic sheeting and every plug is pulled. Rubber items and fragile collectibles are moved out, and ozone is applied at a controlled dose with no people, animals or plants in the room.
6. Ventilation. Doors, windows and exhaust fans are opened until the ozone has broken down back into oxygen, before teachers and students return.
7. Follow-up check. The team checks the odor and the wall behind the shelves again. If it is still damp, they recommend moving the shelves slightly away from the wall so air can circulate.

Ozone, Books and Electronics: What to Be Careful About

• Ozone is very good at dealing with odors and airborne spores, but it does not dry wet books. Books must be dried first, and only then can ozone fully reduce the musty smell.
• Rubber parts such as elastic bands, printer rollers and the rubber feet on devices can age faster if exposed to high ozone concentrations for a long time. That is why dose and duration are controlled and sensitive items are covered or removed.
• Rare books, school history archives and old photographs should be stored separately, given special care and kept out of the room during treatment.
• No one may be in the room during ozone treatment. Post "do not enter" signs on every door and ventilate properly before anyone goes back in.
• Do not switch on any computer or device that was submerged until a technician has checked it.

Following these simple rules is how a school gets the benefits of ozone, a fresh room free of musty odor, without trading one problem for another.

Special Attention for the Computer Room: Air Conditioning, Cables and Dust

The computer room has a few problems of its own that the library does not. The first is the air conditioner. When floodwater raises the humidity in a closed room for days, the indoor unit's coil, fan and drain pan become damp and dark, an ideal place for mold and bacteria to settle. That is why the first blast of air after the flood smells so bad. Before the room is treated, the school should have the air conditioner cleaned by a technician, including the filters, coil and drain line. Otherwise, the unit will keep blowing musty air into a room that has just been treated.

The second is cabling. Network cables, power strips and extension leads that were lying on the floor during the flood may look fine once dry, but water and fine silt can remain inside connectors and sockets. The safest approach is to replace power strips that were submerged and to have an electrician test the outlets and wiring before the room is used again.

The third is fine dust. As mud dries, it turns into a fine powder that settles on top of computer cases, inside keyboards and on the vents of monitors. Wiping it away with a damp cloth before treatment, rather than blowing it with a fan, keeps the dust from being spread around the room and drawn into the machines.

A Simple Recovery Timeline for the School

• Days 1 to 3 after the water recedes: Photograph the damage for records, remove soaked carpets and pulped books, wash out mud, and call an electrician to check the power before anything is switched on.
• Days 3 to 7: Sort and air-dry slightly damp books, clean the air conditioners, and book the WHD site survey.
• Days 7 to 10: Fog the floors, walls, desks and shelf frames, cover the equipment, carry out the controlled ozone treatment and ventilate thoroughly.
• Before term starts: Return dry books to the shelves, have a technician check any submerged devices, and do a final odor check with the team.
• First month back: Check the bottom shelves and the wall behind them every week, and contact the team if dark spots or a musty smell return.

Every school is different, so the exact timing will depend on how deep the water was and how quickly the building dries, but having a simple plan like this helps teachers, administrators and parents know what to expect.

10 Reasons Schools Choose WHD to Restore Libraries and Computer Rooms

1. Ozone treatment with a controlled dose, suited to rooms full of paper and equipment.
2. Equipment is always covered and unplugged before treatment.
3. Disinfection fogging is targeted at suitable surfaces, never sprayed straight onto books or computers.
4. CHEMGENE HLD4H has no harsh smell to bother children.
5. It helps remove the damp-paper odor that makes a library feel unwelcoming.
6. Clear advice on sorting books into groups makes the librarian's decisions easier.
7. The team points out hidden risk areas behind shelves that are often missed.
8. The Chemgene HLD4H 750 ml spray lets teachers keep wiping desks and mice afterward.
9. An add-on dust mite removal service is available for cushions and reading corners.
10. Work is scheduled on weekends or after school, so teaching is not disrupted.

Before and After Restoring the Library and Computer Room

A Customer's Perspective (Sample Scenario)

"At first I was really worried the ozone would ruin the computers. The team had us unplug everything, cover every machine, and explained how they control the dose. They also showed us how to sort the books. When the term started, the children went into the library and nobody complained about the smell anymore."
— School librarian, Si Prachan district (scenario based on field experience)

Frequently Asked Questions

Q: Will ozone treatment damage our computers?
A: When devices are unplugged and covered and ozone is used at a controlled dose and duration, the risk is greatly reduced. The team will assess the room and tell you which equipment should be moved out.

Q: Can ozone save books that already have mold?
A: Ozone helps reduce odor and airborne spores, but books must be completely dry first. Books that are pulped or heavily moldy deep into the paper should be considered for write-off so they do not become a source of mold in the room.

Q: Can you spray disinfectant onto the books?
A: We do not recommend it, because moisture from the solution can damage paper. The team fogs floors, walls, desks and shelf frames instead.

Q: How long does it take?
A: It depends on room size and the number of books. In general, the team plans to finish over a weekend or holiday and allows time for ventilation before school reopens.

Q: Can we keep the wet carpet from the reading corner?
A: Carpet soaked in floodwater for several days usually holds germs and mold deep in its fibers. In most cases it should be thrown away and replaced.

Q: How do we stop mold from coming back?
A: Move shelves slightly away from the wall, open windows every morning, use a dehumidifier if you have one, and check the bottom-row books every week during the rainy season.

Q: Do we need to close the whole building?
A: Usually not. The library and computer room can be treated as a separate zone, as long as doors are kept shut and signs are posted while ozone treatment is under way.

Tips for Librarians Handling Damp Books

• Stand slightly damp books upright with the covers fanned open, in a well-ventilated room out of strong sunlight.
• Slip blotting paper or tissue between pages at intervals, and change it often.
• Keep moldy books apart from clean ones so spores do not spread to other volumes.
• Wear a mask and gloves while sorting moldy books, and wash your hands after every session.
• Record every book written off according to school regulations, so the list can support donation requests or replacement purchases.

Involving older students can turn recovery into a lesson. Under supervision and with gloves, they can help log titles, label boxes and design a "welcome back" display for the reopened library. It gives them ownership of the space and teaches them how to care for shared resources. For more on staying healthy after floods, see the Department of Health.

What Parents Want to Know

When a school reopens after a flood, parents often ask the same few questions: Is the air safe? Were chemicals used? Will my child's allergies get worse? It helps to answer them openly. A short note in the school's LINE group or on the noticeboard can explain that the library and computer room were cleaned, disinfected on surfaces with Chemgene HLD4H, treated with ozone while empty, and ventilated before students returned. Mentioning that soaked carpets and moldy books were removed, and that the electrical system was checked, reassures parents that the school took the problem seriously. If a child with asthma or allergies feels unwell in any room, teachers should be ready to move them to a different space and let the parents know, and the school can ask the team to recheck that room.

Give the Library and Computer Room Back to Your Students, Safely for Children and Equipment

Talk to the WHD team to plan controlled ozone treatment and disinfection fogging before the new term.

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

Related Links

• Ozone treatment for odors and chemical residue
• Master Ozone Generator
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Health references: World Health Organization (WHO): Floods · Department of Health, Thailand