Online water quality analysis instrument solution for water plant and secondary water supply system design
I. Program Objectives
Real-time monitoring: 24/7 online monitoring of key indicators of raw water, process water, factory water and secondary water supply.
• Early warning and regulation: optimize water treatment process by using data anomaly alarm to assist water quality risk control.
• Compliance: meet the "Hygienic Standard for Drinking Water" (GB 5749-2022) and local regulatory requirements.
2. Core monitoring parameters and instrument selection
1. Waterworks (process sections)
Process stage | monitoring parameter | Recommend the type of instrument | technical essential |
Raw water inlet | Turbidity, pH, COD, ammonia nitrogen | Multiparameter water quality analyzer (e.g. FESKS FOSTCO 6000HM) | High turbidity and biological adhesion resistant design |
Coagulation/dissolution | Turbidity, residual chlorine, ORP | Online turbidity meter (e.g., FESKS FSTU 5230), residual chlorine analyzer (e.g., FESKS FSCL 5290), ORP (e.g., FESKS FSPH 5280) | High frequency sampling (1 time/min) |
Disinfection/water for factory use | PH Turbidity, residual chlorine | Online turbidity meter (e.g., FESKS FSTU 5230), residual chlorine analyzer (e.g., FESKS FSCL 5290), ORP (e.g., FESKS FSPH 5280) | Support the measurement of chloramine and free chlorine separately |
2. Secondary water supply system
monitoring site | parameter | Recommended instrument | special requirements |
The pump house is flooded | Turbidity, pressure, conductivity | Multi-parameter water quality analyzer (e.g. FESKS FOSTCO 6000HM) | Low maintenance, IP68 protection |
The end of the network | Turbidity, residual chlorine, pH, temperature | Multi-parameter water quality analyzer (e.g. FESKS FOSTCO 6000HM) | wireless data transmission |
3. System architecture design
1. Perception layer: The instrument has Modbus/4-20mA output and supports remote calibration.
2. Transport layer:
• Plant area: industrial Ethernet + optical fiber redundant ring network.
• Secondary water supply: NB-IoT/LoRa wireless transmission, reducing cabling costs.
3. Platform layer:
SCADA system integration (such as Siemens WinCC, Configuration King) supports the following functions:
• Dynamic trend analysis and automatic work order trigger when exceeding the standard
• Mobile push alarm (wechat/sms)
• Control the frequency of the dosing pump in conjunction with PLC
Key implementation points
1. Instrument maintenance:
• Calibrate pH/ORP electrode every month, clean the optical window of turbidimeter quarterly.
• Spare parts strategy: reserve 10% margin to deal with unexpected failures.
2. Data validity:
• Identify sensor drift and reduce false alarms.
3. Special considerations for secondary water supply:
• Preferentially select reagent-free instruments (such as constant voltage method for residual chlorine) to reduce the complexity of operation and maintenance.
• Install anti-tear chassis to prevent artificial damage in old residential areas.
The plan can be further refined according to actual needs, such as adding TOC, heavy metal (lead, arsenic) monitoring or micro-biological early warning system.
