HACH AMTAX sc Ammonia Nitrogen Analyzer
| Brand | HACH |
|---|---|
| Origin | Imported |
| Manufacturer | HACH Company |
| Model | AMTAX sc |
| Measurement Principle | Gas-Sensing Electrode (Ammonia-Selective Electrode) |
| Measurement Ranges (as NH₄-N) | Low Range: 0.05–20 mg/L |
| Medium Range | 1–100 mg/L |
| High Range | 10–1000 mg/L |
| LOD | 0.05 mg/L (low), 1 mg/L (medium), 10 mg/L (high) |
| Accuracy | ±3% ±0.05 mg/L (low), ±3% ±1.0 mg/L (medium), ±4.5% ±10 mg/L (high) |
| Repeatability | ±2% ±0.05 mg/L (low), ±2% ±1.0 mg/L (medium), ±2% ±10 mg/L (high) |
| Response Time (T₉₀) | ≤5 min |
| Measurement Interval | Adjustable from 5 to 120 min |
| Sample Temp. | 4–40 °C |
| Sample pH | 5–9 |
| Operating Temp. | −20–45 °C |
| Relative Humidity | ≤95% non-condensing |
| Power Supply | 230 VAC/50 Hz or 115 VAC/50–60 Hz |
| Power Consumption | 100 W nominal (peak: 1000 VA) |
| Enclosure Rating | IP66 |
| Sample Flow Rate | ≤3 m/s |
| Filtrate Flow | ≥5 mL/min for ≥4 min per 5-min cycle |
| External Cabinet Dimensions | 540 × 720 × 390 mm |
| Analyzer Weight | 35 kg (incl. reagents) |
| Cable Length | 2 m from enclosure |
| Optional Heated Sampling Hose | 5 m or 10 m |
Overview
The HACH AMTAX sc Ammonia Nitrogen Analyzer is a fully automated, on-line instrumentation system engineered for continuous, real-time quantification of ammonium nitrogen (NH₄-N) in aqueous matrices. It operates on the gas-sensing electrode principle: free ammonia (NH₃), liberated from ammonium ions under controlled alkaline conditions, diffuses across a hydrophobic membrane into an internal electrolyte solution, where it alters the pH of a buffered chloride reference solution. This pH shift is detected by a precision pH electrode, generating a Nernstian response directly proportional to the logarithm of NH₃ concentration — which, given fixed sample pH and temperature, correlates stoichiometrically to total NH₄-N. The analyzer is purpose-built for unattended operation in demanding environmental and industrial settings — including drinking water treatment plants, surface water monitoring stations, municipal wastewater influent/effluent streams, industrial process water loops, and regulated discharge points subject to national effluent standards (e.g., EU Urban Wastewater Treatment Directive, US EPA NPDES permit limits).
Key Features
- Triple-range measurement architecture (0.05–20 mg/L, 1–100 mg/L, 10–1000 mg/L NH₄-N) enables optimal resolution and linearity across diverse sample matrices — from pristine source waters to highly concentrated digester liquors.
- Integrated auto-calibration and auto-cleaning cycles minimize operator intervention and ensure long-term measurement stability; calibration intervals are configurable and traceable via audit logs.
- Robust IP66-rated, UV-stabilized enclosure with lockable access supports permanent outdoor installation in exposed environments without additional sheltering.
- Digital “plug-and-play” interface with the HACH sc1000 multi-parameter controller provides seamless integration into existing SCADA or DCS architectures via relay outputs, 4–20 mA analog signals, and Modbus RTU over RS-485 bus.
- Low reagent consumption design extends refill intervals to ≥3 months under typical operational duty cycles, significantly reducing lifecycle operating costs and service frequency.
- On-board self-diagnostic system continuously monitors critical subsystems — electrode potential drift, reagent level, temperature stability, membrane integrity, and fluidic path pressure — and reports fault codes compliant with ISA-84 SIS conventions.
Sample Compatibility & Compliance
The AMTAX sc accepts raw or pre-filtered water samples meeting defined physicochemical constraints: temperature 4–40 °C, pH 5–9, and suspended solids content compatible with optional pre-treatment modules (e.g., Filterprobe sc, FILTRAX ultrafiltration, or heated sampling hose assemblies). It complies with international performance verification protocols including ISO 15681-1:2003 (Water quality — Determination of phosphorus and nitrogen compounds — Part 1: Ammonium nitrogen — Spectrometric method using sodium salicylate) for method equivalence validation. When deployed with sc1000 controllers configured for electronic recordkeeping, the system supports ALCOA+ data integrity principles and can be validated for GLP/GMP-regulated applications requiring 21 CFR Part 11-compliant audit trails, electronic signatures, and secure user role management.
Software & Data Management
All configuration, calibration, diagnostic logging, and historical trend visualization occur through the embedded web interface of the sc1000 controller or via HACH’s PC-based Instrument Manager software. Raw sensor output, calculated NH₄-N values, QC flag status (e.g., “CALIBRATION_DUE”, “MEMBRANE_FAULT”), and environmental metadata (sample temp, ambient temp, elapsed runtime) are timestamped and stored locally for ≥30 days. Data export formats include CSV and XML, supporting direct ingestion into LIMS or enterprise environmental data platforms. Firmware updates maintain backward compatibility and incorporate improvements validated against ASTM D1426 and EN 25663 reference methods.
Applications
- Real-time monitoring of nitrification/denitrification efficiency in activated sludge bioreactors.
- Compliance verification at wastewater treatment plant final effluent discharge points.
- Trend analysis of ammonia breakthrough during granular activated carbon (GAC) or ion exchange column exhaustion.
- Early-warning detection of upstream contamination events in river intake networks.
- Process control feedback for breakpoint chlorination dosing systems.
- Long-term nutrient loading assessment in eutrophication-sensitive reservoirs and estuaries.
FAQ
What sample pretreatment is required before analysis?
Minimal pretreatment is needed for clarified samples. For raw wastewater or high-turbidity surface water, integration with Filterprobe sc (with 5–10 m heated hose option) or FILTRAX ultrafiltration is recommended to prevent membrane fouling and ensure hydraulic stability.
Can the AMTAX sc operate unattended for extended periods?
Yes — with scheduled auto-calibration (e.g., every 24 h), auto-cleaning (every 2 h), and reagent reserves sufficient for ≥90 days, the system achieves >95% uptime in typical municipal deployments.
Is the analyzer compatible with third-party SCADA systems?
Yes — via Modbus RTU over RS-485, 4–20 mA analog output (isolated), and dry-contact relay alarms, enabling interoperability with Siemens Desigo, Schneider EcoStruxure, or Honeywell Experion DCS platforms.
How is measurement traceability maintained?
Each calibration event records operator ID, standard concentration, measured response, deviation from expected value, and timestamp; all entries are write-protected and exportable as PDF audit reports.
What maintenance tasks require certified technician involvement?
Electrode replacement, membrane cartridge exchange, and full fluidic path validation — all documented in the HACH Preventive Maintenance Manual (P/N 59900-00) and aligned with ISO/IEC 17025 competence requirements.
