Prevention of Gas Explosion

Prevention of Gas Explosion

Introduction

Prior to April 2009 explosion, Pennsylvania’s municipal had two fully operational anaerobic sludge digesters. The water treatment plant produced more than 4 million gallons of clean water at any given day. Though the building that housed the treatment plant was equipped with functional monitoring systems, the electrical systems were not explosion proof. As a result, the shockwaves during the explosion triggered electric fires, causing substantial damage to the structures and massive injuries to employees. All investigation evidence pointed to the sludge gas conveyance system piping as the main cause to the explosion.

Components of Sludge gas

Anaerobic bacteria degrade the organic solids that the municipal water treatment process generates. Due to the metabolic process, sludge gas is generated by the bacteria. The main composition of the sludge gas is highly flammable methane that poses the risk of explosion. What makes it even worse is that the workers had no modernized warning systems for possible methanol leaks.

Studies indicate that methane explosions are a rare occurrence in water treatment plants. In fact, a previous water treatment plant explosion in Pennsylvania occurred more than a decade earlier. Its cause was the light used by operators, which ignited residual methane generated in the tank. The State Department of Environmental Protection in Pennsylvania had outlined strict permitting requirements which diminished chances of explosion occurrence. The requirements included proper explosion control and plant design measures. Resultantly the licensed firms had sophisticated ventilation and systems that could monitor explosive gas effectively.

Effects of Pennsylvania Water Treatment Plant Explosion

There is no doubt that the Pennsylvania explosion affected many families. Incompetent plant professionals were fired; others faced the rule of law. The large losses led to the workers compensation insurer of Pennsylvania municipality to initiate reviews of water treatment plants’ safety. In the end, an advisory on the best insurance practices was issued. The implementation of the best engineering practices would result in the prevention of disasters similar to those of Pennsylvania Water treatment plant. Additionally, risk control personnel were deployed to the plant facilities for inspection. Besides, there was a provision of funding for the training of the plant's personnel on matters like integrity evaluation and safety measures.

Over the years, technical assistance grant initiative proved unsuccessful. As such, there was a need for risk control professionals to source for other strategies to cope with the challenge. One of the strategies that seemed viable was the performance of a mechanical integrity study. It involved the utilization of the control methodology for air pollution. The method seeks to locate volatile leaks via a direct observation of the monitoring instrument. The control methodology is viable for detection of leaks in valves pumps and flanges.

Due to the lack of internally experienced personnel to conduct the study, local consulting firm that with specialization in industrial hygiene was hired to accomplish the task. The firm made a decision to utilize Flame Ionization Detector to measure the concentration levels of hazardous combustible gasses like methane.

Conclusion

During the month of March 2011, consulting firm monitored the water treatment plants for six days. Their studies indicated that 5 out of the targeted six plants in Pennsylvania had hazardous leaks that threatened future explosions and worker health concerns. Each water treatment plant received a detailed explanation of the results and the recommendations for areas that needed improvements.  Notably the study concluded that drip trap seals were degradable with time. To ensure that they are properly functional and to replace the badly degraded seals, frequent periodic maintenance checks were necessary.