A school supervisor decided to visit a middle school laboratory. As the supervisor walked to the back of the room to find a seat, the teacher came up to him and mentioned that the student he would be sitting right next to was experiencing a problem with flatulence that morning. The supervisor was undeterred and sat next to the student.
He did quickly notice that there was an odor problem, yet he noticed the odor lingered after the class had been dismissed. Curious, he began looking for the cause of the problem and eventually found it. In the back of the laboratory was a sink that was rarely used.
The supervisor sniffed some more and found that the odor was not coming from a student, but from that sink. Because the sink was rarely used, the water in the trap – the "J," "U," or "P" pipe underneath the drain – had dried out. The trap is designed to hold a certain amount of water to help prevent sewer gasses from being released into the air. When it dries out, the sewer gasses are released.
However, odors are not the only problem that can result when this happens. Because this was happening in a school laboratory, there was the possibility that the sewer gas could come into contact with airborne chemical fumes and potentially cause an explosion or turn a benign gas into something lethal. Sewer odors can also cause people to become irritable, fatigued, get headaches, and suffer from memory problems. This can happen whether the odors are detected or not.
What typically happens in these situations is that a building engineer is called in to clean the drain, possibly pour bleach or some other liquid to help kill the odor, and then run water through the drain. The bleach is unnecessary. Merely running the water through the drain will cure the problem, at least for a while.
What this school classroom was experiencing is actually very common in schools. This is because many schools close entirely for the summer, as well as close for winter and spring breaks during the year. On these breaks, the water in the trap evaporates. As a preventative, many school districts are now pouring a few ounces of specially made water seals or liquid primers that will prevent the drain from drying out for months at a time. With these products, gassy classes can be a thing of the past.
For more information on ways to prevent sewer odors from being released in your facility, contact a Waterless Co representative.
 Story Source: Ken Roy, “An Ounce of Preventive Maintenance,” Science Scope 38, no.8 (2015)