UV254 Analyser – UV254Sense Probe
The UV254Sense Probe offers a method for measuring the levels of organic compounds in water by analyzing its ultra-violet absorbance (UVA) and transmission (UVT). This device operates by continuously flowing water through a specified gap in the probe, allowing a UV254 wavelength light to pass through. It then measures the amount of light that is absorbed (indicative of UVA) and the amount that passes through (indicative of UVT).
Technological advancements in spectral analysis within the ultraviolet light spectrum have enhanced the accuracy of real-time monitoring for organic compounds in water. The UV254 analyzer, which includes capabilities for both UV transmittance and UV absorbance measurements, works by quantifying the light absorbed at a 254nm wavelength. This absorption rate is an effective metric for estimating the concentration of aromatically organic matter in water, which is useful for assessing potential disinfection byproduct (DBP) formation. Manufacturers like Pi have developed UV254 analyzers that not only assess total organic carbon (TOC) levels but are also efficient in detecting natural organic matter (NOM), common across all water sources. This is particularly relevant for understanding DBP formation risks, given the analyzers’ sensitivity to aromatic organic compounds.
The UV254Sense Probe by Pi operates using a 254nm wavelength UV LED light source. This light is directed through a water sample via a sapphire window and detected on the opposite side by a photodiode detector. The difference in the intensity of light emitted and the light received indicates the water’s UVA absorption and UVT transmission rates. This relationship is quantified according to Beer-Lambert’s law.
Cost of Ownership
The UV254Sense Probe UV254 analyser has a relatively low cost for calibration and maintenance due to its lack of reagents and moving parts. Maintenance primarily involves routine cleaning and occasional recalibration using either DI or RO water. An automatic cleaning system can further reduce maintenance efforts, thereby lowering the overall cost. When considering both the acquisition and operational costs, the total cost of ownership for the UV254Sense Probe is lower than many other UV254 measuring instruments.
Key Benefits
- UVA (ultra-violet absorbance) serves as a reliable indicator for TOC, DOC, COD, and color measurements.
- UVT (ultra-violet transmission) assists in determining the necessary UV dosage for disinfection systems to enhance their operational efficiency.
- Enables accurate monitoring without requiring additional reagents, offering a cost-effective solution.
- Facilitates improved coagulation control, helping to reduce chemical usage, lower sludge disposal costs, and decrease the likelihood of DBP (Disinfection By-Product) formation.
- UVA measurements aid in verifying the effectiveness of certain contaminant removal processes, including membrane filtration (RO, NF, UF), ion exchange systems (for nitrates and TOC), and granular activated carbon (GAC) treatments.
- Compatible with CRONOS® or CRIUS®4.0, allowing for integration into a versatile UV254 analysis system tailored to specific requirements.
Standard Features
- Operates continuously online
- Utilizes a UV light source at a wavelength of 254nm
- Shows values for UV transmittance or absorbance
- UVT (Ultra-violet Transmission) – Mainly used for controlling the intensity of UV light in UV disinfection processes.
- UVA (Ultra-violet Absorbance) – Applied for enhancing water treatment processes by adjusting coagulant doses or as an alternative measure for parameters such as TOC or COD.
- Process Control – Involves the direct measurement of parameters to regulate processes like coagulation, UV disinfection, and membranes.
- Specific Parameter Correlation – Employed to estimate values for parameters that are challenging or costly to measure directly, like TOC, BOD, and COD.
- Event Monitoring – Tracks baseline absorbance to alert to changes indicative of potential contamination in municipal settings.
- Industrial Water and Wastewater Secondary and Effluent Monitoring – Assesses treatment efficiency post-secondary treatment and assists in managing tertiary treatment.
- A single analyzer can accommodate multiple sensors.
- Installation options include dip mounting or at-line mounting.
- Features a self-cleaning mechanism.
>> Coagulation Control
>> Coagulant Dose Determination in 5 Minutes!
UV254 measurement involves a process where light of a specific wavelength (254 nanometers) is passed through water to determine the absorption by water contaminants. These contaminants could be either particulate matter or organic compounds that have the ability to absorb at this wavelength.
UV measurement is employed in water treatment through two primary methods. Firstly, it’s used to assess the transmittance of UV light, which is crucial for deciding the intensity of UV light needed for disinfecting water. Secondly, UV measurement helps in determining the absorption of UV light, indicating the presence of organic materials in the water. This measurement often serves as a surrogate for total organic carbon (TOC), dissolved organic carbon (DOC), and chemical oxygen demand (COD), and is typically utilized for managing coagulation processes in water treatment facilities.
UVA and UVT are related measurements, though they are expressed differently. Specifically, UVA can be calculated as 2 minus the log base 10 of UVT. This indicates that while they measure similar properties, they are presented in distinct formats.
The presence of color in raw water often indicates organic materials. Consequently, both UV254 readings and water color can be indicators of organic content. While color monitoring is effective for assessing water’s appearance, it doesn’t always capture the presence of organics that lack visible coloration. Additionally, various factors, including manganese, can impart color to water, further complicating assessments based solely on color. UV254 is a more precise method for detecting aromatic organics, which are relevant because they can react with chlorine to produce undesirable disinfection by-products (DBPs). Therefore, UV254 is generally considered more advantageous for controlling coagulation processes than relying on color measurements alone.
TOC (Total Organic Carbon) represents a measurement that can be challenging and costly to perform in real-time; however, UV254 measurements may serve as an alternative indicator. This approach requires establishing a correlation between TOC and UV254 values through offline analysis, which can then be programmed into the analyzer to estimate TOC based on UV254 readings. The accuracy of this correlation largely depends on the composition of the TOC. If the TOC primarily consists of compounds that absorb at the UV254 wavelength, a strong correlation is observed. Conversely, if the TOC is composed of substances that do not absorb at this wavelength, the correlation weakens, reaching a point of no correlation when the TOC is entirely made up of non-absorbing organics. In practice, the correlation tends to be strong in the context of municipal water and wastewater treatment.
Document | Type | Size |
---|---|---|
UV254Sense Probe | Brochure | 486kB |
UV254Sense – Water | Brochure | 652kB |
UV254 Sample Strainer Unit | Technical Note | 655kB |
Correlating the UV254 Water Quality Parameters to Other Organics Parameters | Technical Note | 666kB |
Importance of Measuring UV Transmittance (UVT) for UV Disinfection | Technical Note | 445kB |
Benefits of UV Transmittance (UVT) Field Testing for Selling and Servicing UV Disinfection Systems | Technical Note | 459kB |
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