An Avoidable Accident at a Water Treatment Plant

Accidental Keystroke Leads to Water Crisis

“To err is human.” A true statement that is often followed by a domino effect of major consequences. The Orange Water and Sewer Authority (OWASA) in Chapel Hill, NC recently experienced first-hand how a slight mistake can lead to a “worst-case scenario”. The municipal water treatment plant was affected, as well as 80,000 residents in North Carolina’s Orange County area.

A recent article detailed how a distracted water treatment plant operator unintentionally hit a button. This signaled a fluoride feed pump to increase the levels of fluoride in the water. What is normally an 8-12% operating speed for the pump was increased to 80% for approximately three hours.

Authorities discovered that the plant operator noticed disparate fluoride levels at one point and went to review the data to make adjustments. That operator then became distracted and forgot to check the issue, then making a computer keystroke that unintentionally triggered the inciting event.

The Consequences of Out-of-Date Methods 

While OWASA officials established “that no water with increased fluoride levels made it into the drinking water for OWASA customers,” this breach did trigger an emergency water interconnect from the city of Durham. The following day, a water main funneling the water from Durham had a break. This forced a Do Not Drink/Do Not Use order for southern Orange County residents and businesses for more than 24 hours.

The Health Department responded by closing all hotels and restaurants served by OWASA. They even postponed and relocated the UNC men’s basketball game against Notre Dame. In all, nearly 80,000 people were affected by this accidental error that quickly ballooned.

Could This Error Have Been Avoided?

Once each of the subsequent issues was managed and under control, investigators began their search for the how to best prevent a problem like this from happening in the future.

The water main break was the result of outdated and old infrastructure. Simply put, the water treatment plant was not up to standards for the increased water supply. Additionally, water levels were checked manually. This is no longer necessary. Modern technology, such as Cloud-Based SCADA Monitoring Systems, is widely available. SCADA provides real-time, accurate readings of water levels and other relevant data. The last issue investigators uncovered was that training procedures for employees were not as compliant or practical as necessary.

All of this added up to a huge accidental error. Fortunately, the consequences were kept to a minimum. But the whole situation could have been easily avoidable with updated technology and practices.

Web & Cloud-Based SCADA Systems

The most important takeaway from this event is the need for better monitoring and alert systems. Water treatment is vital to public safety. Effectively monitoring these practices allows for accurate data collection, as well as a safety net for when a disruption occurs to regulated output.

If OWASA had updated their equipment and made use of a cloud-based SCADA monitoring system, the appropriate operators and departments would have been notified. The SCADA system would have alerted decision makers about the high fluoride levels in the water, allowing them to review real-time data about the situation. Additionally, it would have alerted operators that the emergency water main specs were out-of-date and too short for interconnecting Durham’s water.

A cloud-based SCADA system does not rely on the physical presence (or aptitude) of operators. Instead, it records and transmits data in real-time, making it accessible to the proper departments from anywhere that has an Internet connection.

Accidents happen. But learning from mistakes and taking steps to eliminate repeated problems is the best outcome for scenarios primed to have a domino effect. Humans make errors, but humans can also learn from their mistakes.