Wastewater Treatment Industry Gas Detection Solution: Nexisense Guards the Bottom Line of Safety and Environmental Protection

Wastewater treatment, as a core link in the recycling of water resources, faces various gas risks while treating domestic sewage and industrial wastewater. In areas such as sewage tanks, regulation and storage tanks, chlorination workshops, and dosing rooms, toxic gases such as chlorine gas, hydrogen sulfide, and ammonia are prone to accumulation, threatening the health of operators and equipment stability. With increasingly stringent national environmental standards, enterprises need to equip professional gas detection systems to achieve real-time monitoring and early warning. Nexisense focuses on gas sensing technology, and its SGA-500 online and SGA-600 portable gas detector series are tailored to the pain points of wastewater treatment, providing reliable monitoring solutions that have been stably applied in multiple water utility enterprises.

Overview of Gas Risks in the Wastewater Treatment Industry

The wastewater treatment process involves multiple stages such as biodegradation, chemical disinfection, and physical precipitation, which often generate or introduce harmful gases. The main risk gases include:

• Chlorine gas (Cl2): Pale yellow highly toxic gas, used for disinfection and sterilization. Short-term exposure irritates the respiratory tract, causing coughing and chest tightness; high concentrations can cause pulmonary edema and even be life-threatening.

• Hydrogen sulfide (H2S): Colorless gas with a rotten egg odor, originating from anaerobic decomposition of organic matter. Low concentrations irritate eyes and respiratory tract, while high concentrations inhibit the central nervous system, leading to rapid coma.

• Ammonia (NH3): Pungent odor gas, coming from urea decomposition or dosing processes. Exposure can cause bronchitis, and in severe cases damage liver and kidney function.

• Carbon dioxide (CO2) and biogas (CH4): Colorless and odorless, accumulating at the bottom of confined tanks, leading to oxygen deficiency or explosion risks.

• Carbon monoxide (CO): Colorless and odorless, originating from incomplete combustion or sewage fermentation, binding to hemoglobin causing poisoning.

These gases are prone to exceeding limits at the bottom of poorly ventilated regulation and storage tanks or sewage tanks. According to industry reports, wastewater treatment plants without monitoring systems account for more than 25% of gas-related accidents. Traditional inspections rely on manual labor, which is inefficient and dangerous, while automated detection systems can provide 24-hour coverage, combined with data analysis to optimize process flows, ensuring compliance with standards such as GB 50058-2014 (Code for design of electric power installations in explosion and fire hazard atmospheres).

Core Technology and Features of Nexisense Gas Detectors

Nexisense products use imported sensor cores, with secondary calibration, temperature and humidity compensation, and anti-interference optimization to ensure stable operation in humid and dusty wastewater treatment environments. The series includes the online SGA-500 and portable SGA-600, meeting the needs of fixed monitoring and mobile inspection.

SGA-500 Online Gas Detector Details

This series is suitable for fixed locations such as chlorination workshops and dosing rooms, supporting wall-mounted or pipeline installation. Key features:

• Multi-gas compatibility: Can monitor chlorine gas, hydrogen sulfide, ammonia, carbon dioxide, carbon monoxide, biogas, etc., with single-unit multi-channel configuration.

• Flexible signal output: Supports 4-20mA current loop, RS485 Modbus-RTU, 0-5V voltage and other interfaces, convenient for integration with PLC or DCS systems.

• Diverse sampling methods: Diffusion, pump suction or pipeline sampling, adapting to different flow rates and concentrations.

• Alarm and display: Built-in LCD screen, audible and visual alarm, high and low alarm thresholds can be set, linking exhaust fans or valves.

• Wiring options: Two-wire, three-wire, four-wire systems, simplifying wiring and reducing costs.

The product has IP65 protection rating, corrosion-resistant shell, operating temperature -20℃～+50℃, suitable for harsh conditions in sewage plants. Factory calibrated, no complex on-site commissioning required, long maintenance cycle.

SGA-600 Portable Gas Detector Details

For mobile scenarios such as sewage tank maintenance and bottom inspection, this series is compact and has long battery life (>8 hours). Highlights include:

• Flexible sampling: Diffusion, pump suction or probe rod type, probe rod can extend into the tank bottom for safe sampling.

• Intelligent functions: Light-sensing automatic backlight, data storage (supports Excel export), average value calculation (1 minute/1 hour), temperature and humidity display, unit switching (ppm/mg/m³), multi-language support.

• Ergonomic design: Anti-slip grip, audible-visual-vibration alarm, ensuring timely operator response.

• Expandability: Optional Bluetooth transmission, real-time data upload to mobile APP or cloud platform.

Both have passed explosion-proof certification (Ex ib IIC T4 Gb), sensor lifespan 2-3 years, simple periodic calibration.

Typical Application Scenarios and Implementation Cases

In wastewater treatment plants, gas detection system deployment is as follows:

• Chlorination/dosing workshop: SGA-500 fixed installation, monitoring chlorine gas and ammonia, automatically starting ventilation when abnormal.

• Regulation and storage tanks and sewage tanks: SGA-500 wall-mounted at tank edges, combined with SGA-600 portable handheld inspection, covering tank bottom blind spots.

• Biogas collection area: Monitoring biogas and carbon dioxide to prevent explosion and oxygen deficiency.

• Overall plant management: Multi-point networking to form gas distribution maps, supporting remote monitoring.

Multiple water utility enterprises have adopted Nexisense solutions. For example, after a large sewage plant integrated SGA-500, gas exceedance response time was reduced by 50%, successfully passing safety assessments. In another project, SGA-600 assisted maintenance teams in avoiding multiple potential poisoning incidents.

When implementing, enterprises should evaluate gas types, concentration ranges, and installation points. Nexisense provides on-site survey, solution design, and training services to ensure efficient system operation.

Common Questions and Answers (FAQ)

Q1: Which common wastewater treatment gases do Nexisense SGA-500 and SGA-600 series support? Can they be customized according to specific wastewater types in the plant?

A1: Standard configuration covers main risk gases such as chlorine gas (Cl2), hydrogen sulfide (H2S), ammonia (NH3), carbon dioxide (CO2), carbon monoxide (CO), and biogas (CH4/LEL). For special industrial wastewater (such as fluorine-containing, heavy metal-containing, or high-concentration organic wastewater), we provide customization services that can add specific gas channels (such as hydrogen cyanide, benzene series) or adjust ranges (such as H2S as low as 0.1ppm high sensitivity). The customization process includes customers submitting wastewater composition analysis reports, historical on-site gas concentration data, and regulatory requirements; we select sensors and optimize cross-interference compensation algorithms accordingly, usually completing prototype delivery within 4-8 weeks.

Q2: How is the long-term stability of the online SGA-500 in high-humidity, highly corrosive sewage tank environments? What protective measures are recommended?

A2: The product uses 316L stainless steel or engineering plastic corrosion-resistant shell, IP65/IP66 protection rating, with advanced built-in temperature and humidity compensation algorithms. In typical sewage plant environments (temperature 5-40℃, humidity 80-100%RH, containing acid-alkali mist), zero drift <±2%FS/year, span error <±5%. Actual continuous operation projects show accuracy degradation less than 8% after 2 years. Recommended measures: 1) Choose installation locations with better ventilation or add local exhaust; 2) Install waterproof breathable membrane and activated carbon filter in front of the probe to prevent clogging/corrosion; 3) Clean the surface quarterly with clean air; 4) Perform comprehensive calibration annually.

Q3: How is the safety and operational convenience of the portable SGA-600 ensured during bottom inspection of sewage tanks?

A3: SGA-600 has Ex ib intrinsically safe explosion-proof certification, suitable for Zone 0/1 hazardous areas. Probe rod sampling length up to 1.5-3m, allowing operators to sample safely from the tank edge without entering oxygen-deficient or highly toxic spaces. Alarm mechanism includes triple audible-visual-vibration reminders, thresholds support customization (e.g., H2S 5/10/20ppm three levels). Ergonomic design: weight <500g, anti-slip grip, one-hand operation; battery life 8-12 hours, supports USB-C fast charging or vehicle charging. Data storage capacity >100,000 entries, one-click report export, convenient for post-analysis and safety supervision filing.

Q4: How does the detector's signal output seamlessly integrate with the existing SCADA or PLC system in the sewage plant? Is there development support?

A4: SGA-500 supports 4-20mA (two/three/four-wire), RS485 Modbus-RTU (most recommended, transmission distance >1000m), relay switch quantity and other standard interfaces. Complete Modbus register mapping table, communication protocol documentation, sample code (supporting mainstream PLCs such as Siemens S7, Schneider, Rockwell) and host computer monitoring software (real-time curves, historical data, alarm logs, automatic reports) are provided. Integration cycle is usually 1-3 weeks. For SGA-600, optional Bluetooth/WiFi module enables wireless data upload to cloud platform or mobile APP, supporting MQTT protocol docking with plant MES.

Q5: What factors affect sensor lifespan? How to effectively control maintenance costs and extend service life?

A5: Electrochemical sensor lifespan is generally 2-3 years, infrared/catalytic combustion type can reach 4-5 years. Main influencing factors: 1) Long-term high-concentration exposure accelerates electrolyte consumption; 2) Extreme humidity fluctuations cause condensation corrosion; 3) Dust, oil mist or chemical mist adhesion blocks the diaphragm. We recommend: monthly visual inspection of probe; quarterly zero-point calibration (clean air); annual or after accumulated 8000 operating hours, perform span calibration with standard gases; add pre-filters in high-pollution areas. Maintenance cost is about 12-18% of equipment total price per year. We provide modular sensor replacement service (completed on-site in 10 minutes) and annual maintenance contracts, with discounts for bulk users.

Q6: Has the product passed relevant national standards and certifications? How is it applied in sewage plant environmental impact assessment and safety supervision review?

A6: It has obtained national measuring instrument type approval (CMC), explosion-proof certificate (Ex ib IIC T4 Gb), electromagnetic compatibility (EMC) testing, and complies with GB 12358-2006 (General technical requirements for gas detection alarms in workplaces), GB 3836 series (Electrical apparatus for explosive gas atmospheres), HJ 212-2017 (Data transmission standard for online monitoring of pollutants) and other specifications. Detection data can be directly used as proof materials for sewage plant safety risk assessment, occupational health protection, and environmental acceptance. Export models additionally meet IECEx/ATEX, CE requirements, providing bilingual Chinese-English certificates.

Q7: What response mechanisms does the system have when gas exceeds the limit? How to avoid production interruptions caused by false alarms?

A7: Supports three-level alarm threshold settings (warning/alarm/high limit), each level can independently configure concentration, delay time (1-60 seconds to prevent transient fluctuations), and linkage actions. Trigger responses include: 1) Local audible and visual alarm (≥90dB); 2) Relay output controls exhaust fans, solenoid valves or warning lights; 3) RS485 sends alarm messages to central control; 4) Optional SMS/WeChat/APP push. False alarm control strategies: concentration trend judgment (continuous exceedance for N seconds to confirm), multi-point averaging filtering, environmental compensation algorithms. In actual projects, options such as “manual reset confirmation” or “only high limit linkage shutdown” can effectively balance safety and production continuity.

Q8: How to quickly obtain technical materials, selection advice, prototype trial or on-site support?

A8: Visit the “Wastewater Treatment Solutions” page on the Nexisense official website to download product manuals, selection tables, 3D models and case reports; or contact sales/technical support, providing plant layout drawings, main gas types, concentration ranges, number of installation points and budget range. We usually reply with detailed solutions and quotes within 24-48 hours. For key projects, free prototype trials (1-2 months, including on-site installation guidance, simulated gas testing and data analysis) or engineer on-site survey and demonstration can be arranged to ensure selection matches actual needs.

Summary

Wastewater treatment gas detection is key to ensuring operational safety and optimizing resource utilization. Nexisense SGA-500 and SGA-600 series provide comprehensive monitoring support for enterprises with advanced technology and practical design, helping transition from risk prevention to intelligent operation and maintenance. Facing water resource scarcity and environmental pressure, early deployment of reliable systems will enhance industry sustainability. Nexisense is committed to technological iteration and working with water utility partners to create a green future.