Sierra Monitor knows the Wastewater application inside and out. Consider using Sierra Monitor’s expertise and products for your next wastewater project — instrumenting the wastewater plant with one of the most comprehensive gas detection, alarming, and mitigation systems available.
Although detecting hazardous gases within a wastewater treatment facility is important, integrating gas detection and alarm systems with SCADA’s, PLC’s, or BMS’s is equally as important. FieldServer protocol gateways are essential to integrating key wastewater facility automation systems to the cloud for remote monitoring, control, and big data analytics.
Wastewater is used water that has been adversely affected in quality by substances like human waste, food scraps, oils, and chemicals. Wastewater treatment, also known as sewage treatment, is the process of removing contaminants from wastewater through physical, chemical, and biological procedures. Wastewater treatment facilities clean used water for the benefit of our environment and personal health. However, the treatment process is chemically intensive and can pose a threat to the safety of personnel working at the facility. Consequently, the wastewater treatment facility manager must ensure that the facility’s safety is not compromised by instrumenting the plant with a comprehensive gas detection, alarming, and mitigation system.
Gas Detection and Alarming
The process of treating wastewater requires a plant to utilize many toxic and dangerous gases, which also causes the production of other toxic and combustible gases. Moreover, there are many enclosed spaces in a wastewater treatment plant where toxic gases can build up, or non-toxic gases can deplete oxygen to endanger plant personnel. To ensure maximum wastewater treatment safety, these hazardous gases must be accounted for:
Combustible Gases
Methane (CH4)
Pentane (C5H12)
Hydrogen (H2)
Hydrogen Sulfide (H2S)
Oxygen (O2) Deficiency
Carbon Monoxide (CO)
Chlorine (Cl2)
Sulfur Dioxide (SO2)
Processes within a wastewater treatment facility include pumping and lifting stations, influent screening, sludge processing, digestion, and final disinfection. Different processes within a wastewater treatment facility require different gas sensors. Areas with potential hazardous levels of gases include:
Pumping station and wet well – Combustible Gases, Oxygen Deficiency, Hydrogen Sulfide
Influent and barscreen room – Combustible Gases, Hydrogen Sulfide, Oxygen Deficiency
Barscreen and conveyor room – Combustible Gases, Hydrogen Sulfide
Barscreen container and grit screen room – Combustible Gases, Hydrogen
Primary Clarifier – Combustible Gases, Oxygen Deficiency, Hydrogen Sulfide
Primary wet wall – Combustible Gases, Oxygen Deficiency, Hydrogen Sulfide
Grit chamber and wet wall – Combustible Gases, Oxygen Deficiency, Hydrogen Sulfide
Sludge treatment – Combustible Gases, Oxygen Deficiency, Hydrogen Sulfide
Sludge incineration – Carbon Monoxide
Basement-generator area – Combustible Gases
Digester-basement – Combustible Gases, Hydrogen Sulfide
Digester-first floor – Combustible Gases, Hydrogen Sulfide
Odor removal equipment – Chlorine, Hydrogen Sulfide, Ammonia
Furnace room – Combustible Gases, Carbon Monoxide
Filtration room – Chlorine, Hydrogen Sulfide
Final disinfection – Chlorine, Ammonia, Sulfur Dioxide
Automation and Integration Strategies
Detecting hazardous gases and issuing alarms are important steps, but it is equally important to take remediation actions. This can be done through integrating the gas detection and alarm system with the Supervisory Control and Data Acquisition (SCADA), the Programmable Logic Controller (PLC) or the Building Management System (BMS) responsible for automating the larger facility. Other automation processes may include providing notifications as a local alarm to an employee’s phone, tablet, and/or PC.
As these systems are automated, the regulatory agencies require that the systems be “performance approved” and checked on a periodic basis.
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