Shenchanghong PWN-820B Portable COD and Total Phosphorus Analyzer
| Brand | Shenchanghong |
|---|---|
| Origin | Guangdong, China |
| Manufacturer Type | Direct Manufacturer |
| Country of Origin | China |
| Model | PWN-820B |
| Instrument Type | Portable |
| Measurement Principle | UV-Vis Absorption Spectrophotometry (610 nm) |
| COD Range | 0–2000 mg/L |
| Total Phosphorus Range | 0.00–10.00 mg/L |
| Accuracy | ≤ ±5% (COD & TP) |
| Repeatability | ≤ ±3% |
| Detection Limit | 0.1 mg/L (COD), 0.01 mg/L (TP) |
| Measurement Time | 15 min per batch |
| Batch Capacity | 10 samples |
| Optical Drift | < 0.002 A in 20 min |
| Chloride Interference Tolerance | ≤ 2000 mg/L (for COD) |
| Dimensions (Analyzer) | 80 × 230 × 55 mm |
| Dimensions (Digestor) | 105 × 160 × 90 mm |
| Enclosure Rating | IP65 |
| Power | DC 12 V (AC/DC adapter included) |
| Data Storage | 199 measurement records with timestamp (YYYY-MM-DD hh:mm:ss), plus 30 user-defined calibration curves |
| Interface | USB port for data export and PC connectivity |
| Housing Material | Molded ABS |
Overview
The Shenchanghong PWN-820B is a field-deployable, dual-parameter spectrophotometric analyzer engineered for simultaneous quantification of Chemical Oxygen Demand (COD) and total phosphorus (TP) in natural waters, wastewater effluents, and treated discharge streams. It operates on the principle of absorption photometry at 610 nm—optimized for the molybdenum blue reaction (for TP) and dichromate-based oxidation coupled with colorimetric detection (for COD). Unlike benchtop systems requiring centralized lab infrastructure, the PWN-820B integrates a dedicated 4-position digestion unit with a compact, handheld photometer—enabling full analytical workflow completion in situ. Its optical architecture employs a cold light source and narrow-band interference filters to ensure long-term photometric stability (<0.002 A drift over 20 minutes), critical for regulatory-grade field measurements under variable ambient conditions.
Key Features
- Modular design: Independent digestion module and photometer prevent thermal cross-interference, preserving measurement integrity during sequential or parallel operation.
- PID-controlled digestion system: Maintains precise temperature setpoints (typically 165 °C for COD, 120 °C for TP) with automatic timing—eliminating manual stopwatch dependency and reducing operator error.
- Low-power embedded architecture: 16-bit microcontroller enables up to 6 months of standby operation on internal battery (with optional external power via 12 V DC input).
- Ruggedized field housing: IP65-rated ABS enclosure resists dust ingress and water splashes—validated for use in humid riverbanks, municipal pumping stations, and industrial outfall sites.
- Comprehensive data governance: Stores 199 time-stamped results (including absorbance, transmittance, and concentration) plus 30 customizable calibration curves—all retained after power loss.
- Regulatory-ready connectivity: USB interface supports secure data extraction to Windows-based laboratory information management systems (LIMS) or audit-compliant spreadsheet logging.
Sample Compatibility & Compliance
The PWN-820B accommodates standard 16 mm OD glass digestion tubes (20 supplied), compatible with EPA Method 410.4 (COD) and ISO 6878:2004 (total phosphorus). Its chloride tolerance of ≤2000 mg/L aligns with common interference thresholds defined in ASTM D1253 and APHA Standard Methods 5220D. While not certified to ISO/IEC 17025 for accredited testing, the instrument meets essential performance criteria for routine environmental monitoring under national surface water quality standards (e.g., China’s GB 3838-2002 and EU WFD Annex V screening protocols). All firmware operations support GLP-aligned traceability through embedded timestamps and non-volatile memory retention.
Software & Data Management
No proprietary software installation is required. Raw absorbance values, calculated concentrations, and metadata (date, time, operator ID if manually entered) are exported as CSV files via USB mass storage mode. Timestamped records include year-month-day-hour-minute-second resolution—supporting chronological reconstruction for QA/QC review. Calibration curve coefficients (linear or polynomial) are stored per parameter and can be recalled, edited, or overwritten without factory reset. Data export complies with basic FDA 21 CFR Part 11 expectations for electronic record retention—though digital signature functionality is not implemented.
Applications
- Field verification of wastewater treatment plant (WWTP) effluent compliance against discharge permits (e.g., TP < 0.5 mg/L, COD < 50 mg/L).
- Rapid assessment of agricultural runoff and eutrophication risk in lakes and reservoirs.
- Pre-screening of industrial process water prior to lab submission—reducing turnaround time and analytical cost.
- Educational use in environmental science field courses requiring portable, hands-on water quality instrumentation.
- Emergency response monitoring following chemical spills or sewage overflows where immediate COD/TP profiling informs mitigation decisions.
FAQ
Can the PWN-820B measure COD and total phosphorus simultaneously?
No—measurements are sequential. The same sample batch must undergo separate digestion protocols (different temperature/time settings) and wavelength-specific readings.
Is method validation documentation available for regulatory submissions?
Instrument-specific validation reports are not provided; users must perform in-house method verification per local regulatory requirements (e.g., spike recovery, matrix interference testing).
What maintenance is required for long-term field reliability?
Optical path cleaning with lint-free wipes and isopropyl alcohol every 50 measurements; annual verification of digestion temperature accuracy using a calibrated thermocouple probe.
Does the device support multi-point calibration curves?
Yes—up to 30 independent calibration sets may be stored, each supporting linear or quadratic regression models derived from user-prepared standards.
Are replacement digestion tubes and reagents supplied by Shenchanghong?
Original consumables—including matched glass tubes, pre-dosed COD vials, and TP reagent kits—are available directly from the manufacturer with lot-specific QC certificates.
