Handheld Water COD and Ammonia Nitrogen Meter

I. Product Overview

This product is a handheld chemical oxygen demand (COD) and ammonia nitrogen (NH₃-N) dual-parameter water quality testing system, designed for simultaneous on-site determination of organic and ammonia nitrogen pollution. The system comprises a handheld main unit and a multi-purpose accessory case: the main unit integrates an intelligent detection module and can perform colorimetric analysis independently, while the 6-position digester in the accessory case provides the pre-treatment required by the national standard method for COD. This design allows operators to complete independent or consecutive determination of the two key parameters on the same platform, in the laboratory or at sites with a power supply, greatly improving on-site testing efficiency.

II. Applicable Standards

HJ 535-2009 《Water quality — Determination of ammonia nitrogen — Nessler's reagent spectrophotometric method》
HJ 536-2009 《Water quality — Determination of ammonia nitrogen — Salicylic acid spectrophotometric method》
HJ/T 399-2007 《Water quality — Determination of chemical oxygen demand — Rapid digestion spectrophotometric method》

III. Measuring Principle

This system is based on spectrophotometry and determines the two parameters according to the respective national standards. COD: HJ/T 399-2007 rapid digestion spectrophotometry — after high-temperature rapid digestion in the digester the sample is oxidised by potassium dichromate, and COD is calculated from the change in absorbance of the reaction liquid at a specific wavelength. Ammonia nitrogen: Nessler's reagent method (HJ 535-2009) or salicylic acid method (HJ 536-2009) — the sample reacts with the corresponding reagent to form a coloured complex, and the absorbance at the characteristic wavelength is measured to calculate the ammonia nitrogen concentration directly.

IV. Applications

Industrial wastewater: influent, process units and outfall monitoring at wastewater treatment stations in electroplating, printing and dyeing, pharmaceutical and food processing plants.
Municipal sewage: influent, biological units, effluent and reuse water inspection at wastewater treatment plants.
Environmental water bodies: rivers, lakes, reservoirs and wetlands, groundwater monitoring wells and private water sources — routine monitoring and pollution screening.
Drinking water safety: drinking water source protection areas, backup sources and rural centralised water supply facilities.
Enforcement and emergency response: surprise sampling at enterprise outfalls, park outfall patrols, on-site screening of sudden water pollution incidents and pollution plume tracking.
Research and teaching: water quality research, process optimisation and on-site testing and data collection for teaching experiments.

V. Key Features

1. Android-based operating system with an elegant, user-friendly interface.

2. 4.3-inch HD touch screen with visual graphical pages, greatly improving operating efficiency.

3. High-reliability imported LED light source requiring no warm-up and offering long-term stability.

4. 10 mm × 10 mm large-area photocell for high sensitivity and a low detection limit.

5. 16 GB internal memory for more than 10,000 records; an optional Bluetooth printer allows results to be printed on site.

6. Wi-Fi and Bluetooth, plus a USB port for direct high-speed batch upload to a PC.

7. Water-resistant housing; the measuring chamber resists ingress of 0.5 mL of liquid.

8. Standard USB-C 5 V 2.1 A with BC 2.1 charging protocol support — compatible with third-party phone chargers, cables and power banks; intelligent lithium battery charge management allows long periods of mains-powered operation.

9. Bilingual Chinese/English operating system.

VI. Technical Parameters