| pH and ORP Monitors | pH, oxidation-reduction potential, and temperature | pH 0–14; ORP approximately −2,000 to +2,000 mV; temperature commonly 0–100 °C | Glass or ISFET pH electrodes; platinum or gold ORP electrodes; automatic temperature compensation | Two-point or multi-point calibration; replaceable sensors; optional automatic cleaning and electrode diagnostics | 4–20 mA RS-485 Modbus RTU Relay alarms | Drinking-water treatment, wastewater neutralization, chemical processing, aquaculture, and industrial process control | Electrometric pH measurement is commonly based on ISO 10523 and Standard Methods procedures |
| Conductivity and TDS Monitors | Electrical conductivity, resistivity, salinity, and total dissolved solids | From low-conductivity water ranges in the µS/cm scale to approximately 2,000 mS/cm, depending on the cell | Contacting conductivity cells or inductive/toroidal sensors with temperature compensation | Multiple cell constants; automatic range selection; compensation for temperature-related conductivity changes | 4–20 mA RS-485 Modbus RTU Data logging | Reverse-osmosis systems, boiler and cooling water, ultrapure-water systems, food processing, and wastewater reuse | Conductivity measurement is commonly evaluated using ISO 7888 and equivalent laboratory methods |
| Dissolved Oxygen Monitors | Dissolved oxygen concentration, saturation, and temperature | Approximately 0–20 mg/L in freshwater applications; higher ranges may be configured for pressurized or saline systems | Optical luminescent dissolved oxygen or electrochemical membrane sensors | Low-maintenance optical options; automatic temperature and salinity compensation; suitable for continuous aeration control | 4–20 mA RS-485 Modbus RTU Cloud gateway options | Activated-sludge treatment, aquaculture tanks, surface-water monitoring, fermentation, and environmental research | Optical and electrochemical methods are commonly assessed against ISO 5814 and Standard Methods procedures |
| Turbidity Monitors | Turbidity and suspended-particle loading | Typical ranges include 0–100 NTU, 0–1,000 NTU, or extended ranges for heavily loaded wastewater | Infrared nephelometric measurement, commonly using 90-degree scattered light detection | Automatic optical compensation; wiper or air-cleaning options; low-range configurations for treated drinking water | 4–20 mA RS-485 Modbus RTU Relay alarms | Raw-water intake, clarification, filtration, drinking-water distribution, and industrial wastewater discharge | Designs commonly reference ISO 7027 for infrared nephelometric turbidity measurement |
| Residual Chlorine Monitors | Free chlorine, total chlorine, chlorine dioxide, and pH | Commonly 0–5 mg/L or 0–20 mg/L as chlorine, depending on the application | Amperometric membrane sensors or colorimetric reagent-based analysis | Continuous measurement; optional pH compensation; automatic cleaning and reagent management on selected systems | 4–20 mA RS-485 Modbus RTU Alarm relays | Municipal drinking-water networks, disinfection processes, swimming pools, food plants, and cooling systems | Colorimetric verification is commonly performed using DPD procedures described in Standard Methods and ISO methods |
| Ammonia-N and Nitrogen Monitors | Ammonia nitrogen, nitrate, nitrite, and total nitrogen indicators | Application-dependent ranges commonly extend from low mg/L levels to approximately 100 mg/L or more | Ion-selective electrodes, gas-sensitive electrodes, UV-visible spectrophotometry, or reagent-based colorimetry | Automatic calibration and cleaning options; compensation for matrix effects varies by sensor technology | 4–20 mA RS-485 Modbus RTU Remote monitoring | Municipal wastewater, livestock farms, aquaculture, fertilizer production, and receiving-water protection | Verification is commonly carried out using spectrophotometric, ion-selective, or flow-injection methods |
| COD and Organic-Matter Monitors | Chemical oxygen demand, UV254 absorbance, TOC, or surrogate organic-load indicators | Typical COD configurations range from low mg/L levels to several thousand mg/L, based on the sample matrix | UV-visible spectrophotometry, UV254 absorbance, chemical digestion, or total organic carbon analysis | Reagent-free UV options reduce consumables; digestion-based systems can provide direct COD results but require maintenance | 4–20 mA RS-485 Modbus RTU USB export | Industrial effluent, municipal wastewater, process-water control, and environmental compliance monitoring | Final COD confirmation is commonly performed using dichromate digestion methods such as ISO 6060 or equivalent national methods |
| Oil-in-Water Monitors | Dispersed oil, hydrocarbons, and petroleum residues | Commonly configured from low µg/L or mg/L levels to higher ranges for industrial wastewater | Ultraviolet fluorescence, infrared absorption, or light-scattering detection | High sensitivity for selected hydrocarbon types; sensor response depends on oil composition and sample conditioning | 4–20 mA RS-485 Modbus RTU Alarm output | Refineries, petrochemical plants, ship bilge-water systems, stormwater, and industrial discharge points | Calibration and validation generally require oil-specific reference materials and an applicable laboratory method |
| Multiparameter Water Quality Stations | Combination of pH, ORP, conductivity, temperature, dissolved oxygen, turbidity, and selected nutrients | Each parameter uses an independent sensor range; modular probes allow application-specific configuration | Integrated sensor platforms with digital signal processing, automatic compensation, and centralized data acquisition | Modular installation; sensor replacement without changing the entire station; optional automatic wipers and anti-fouling systems | 4G/5G LoRaWAN Ethernet GPS Cloud dashboard | Rivers, lakes, reservoirs, aquaculture facilities, drinking-water sources, and emergency pollution investigation | Station design and verification are normally aligned with local environmental monitoring requirements and parameter-specific standards |
| Online Water Quality Data Systems | Real-time acquisition, storage, alarms, reporting, and remote diagnostics | Supports multi-channel data collection from individual sensors, analyzers, and sampling cabinets | Industrial controllers, edge gateways, digital communication protocols, and web-based supervisory software | Configurable sampling intervals; audit trails; threshold alarms; backup storage; remote calibration and maintenance records | Modbus RTU/TCP 4G/5G Ethernet API integration | Centralized treatment plants, distributed monitoring networks, industrial facilities, and regulatory reporting workflows | Data-quality procedures should include calibration records, maintenance logs, traceable reference solutions, and site-specific validation |