Coliform bacteria exhibit a growth temperature range of 7–49.5°C, with the optimal growth temperature being below 37°C. Their minimum water activity requirement is 0.95, pH tolerance ranges from 4.0 to 9.0, and they can withstand a maximum salinity of 6.5%. Pathogenic coliform bacteria can survive for several weeks at room temperature, but how long do they persist in water? Notably, coliform bacteria can survive for months in both soil and water environments. They are cold-tolerant, yet their survival is almost impossible in the absence of water.

Rationale for Monitoring Coliform Bacteria in Water  

Uncontaminated water bodies are typically free of pathogenic microorganisms. However, the influx of sewage containing human or livestock excreta and other pollutants can introduce diverse pathogens into water systems, facilitating the transmission of waterborne infectious diseases. Coliform bacteria, fecal streptococci, and other intestinal bacteria are excreted into water bodies via fecal matter. Thus, monitoring coliform bacteria serves as an indicator of the extent of water contamination, enabling the assessment of water quality based on monitoring data.

Recommendation for Hangzhou Modi’s Coliform Group Online Analyzer

The WECT-900 Online Coliform Analyzer adheres to international standard methods and operates on the principle that the change in optical signal is proportional to the enzymatic reaction with cultured bacteria, thereby reflecting the total bacterial count or coliform concentration in the sample. This coliform detection technology, rooted in biosensing, provides an effective tool for responding to water supply contamination. The coliform count in water samples is determined by comparing the attenuation of solution light intensity with that of a non-toxic control blank.

Technical Specifications  

Measurement Method: Enzyme-substrate method;

Detection Parameter: Total coliforms or thermotolerant coliforms;

Measurement Range: 1 CFU/100 mL – 1×109CFU/100 mL;

Repeatability: 5%;

Resolution: 1%;

Measurement Time: < 12 hours;

Cleaning & Maintenance: Automatic cleaning and disinfection before and after measurement;

Measurement Modes: Timed, interval-based, manual;

Calibration Modes: Automatic scheduled calibration or manual calibration;

External Sampling: Submersible pump and self-priming pump options;

Display: 8-inch color touchscreen (800×600 resolution);

Data Storage: 1 year of valid data;

Alarm Signals: Temperature anomaly, mechanical failure, detection result error;

Data Transmission: 4–20 mA; RS232; RS485;

Operating Temperature: 0–40°C;

Power Supply: 220 V AC ±10%, 50 Hz ±5%;

Power Consumption: ~100 W;

Dimensions: 490×1340×375 mm (W×H×D);

Weight: 45 kg.