Digerui DA18 Biodegradation Testing System for Aerobic Composting Conditions

Overview

The Digerui DA18 Biodegradation Testing System is an engineered laboratory-scale instrument designed to quantify the inherent aerobic biodegradability of plastic materials under standardized composting conditions. It operates on the principle of respirometric CO₂ evolution measurement—tracking carbon mineralization as a direct indicator of microbial metabolic activity. The system conforms to internationally recognized test protocols including ISO 14855-1:2012 (“Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions—Method by analysis of evolved carbon dioxide”), ASTM D5338–23 (“Standard Test Method for Determining Aerobic Biodegradation of Plastic Materials Under Controlled Composting Conditions”), and EN 13432:2000 (“Requirements for packaging recoverable through composting and biodegradation”). The DA18 maintains precise environmental control over temperature (58 ± 2 °C), moisture content (50–60% w/w), oxygen availability (>15% v/v), and pH (6.5–8.0) within static, sealed respirometric vessels—ensuring reproducible simulation of industrial-scale thermophilic aerobic composting.

Key Features

• Modular static respirometry architecture with up to 8 parallel test vessels (configurable per user requirement)
• Integrated high-precision NDIR CO₂ gas analyzers (detection limit: <10 ppm; repeatability: ±1.5% of reading)
• Automated daily CO₂ accumulation calculation via stoichiometric integration against blank-corrected baselines
• Programmable incubation chamber with PID-controlled heating and humidity regulation (±0.5 °C, ±3% RH stability)
• Pre-calibrated inoculum compatibility support for mature compost, activated sludge, or defined microbial consortia
• Robust stainless-steel construction compliant with ISO 17025 laboratory infrastructure requirements
• No consumable sensors—NDIR modules are field-serviceable with traceable calibration certificates

Sample Compatibility & Compliance

The DA18 accommodates solid polymeric specimens (films, pellets, molded parts) up to 10 g dry mass per vessel, with particle size ≤10 mm to ensure uniform contact with inoculum. Test substrates must be pre-characterized for total organic carbon (TOC) content using ASTM D7573 or ISO 10694 to compute theoretical CO₂ yield (ThCO₂ = TOC × 3.67). System validation includes reference material testing with microcrystalline cellulose (≥90% biodegradation in 14 days) and polyhydroxybutyrate (PHB) controls. All operational parameters—including temperature logs, CO₂ concentration time-series, and vessel pressure—are recorded at 15-minute intervals, generating audit-ready datasets compliant with GLP (Good Laboratory Practice) and FDA 21 CFR Part 11 electronic record integrity standards.

Software & Data Management

The DA18 is operated via Digerui BioTrack™ v3.2 software—a Windows-based application supporting multi-user role permissions, electronic signatures, and full audit trail functionality. Raw CO₂ data undergoes automatic baseline subtraction, ThCO₂ normalization, and kinetic curve fitting (first-order exponential decay model) to generate biodegradation profiles. Export formats include CSV, PDF analytical reports (with ISO/ASTM clause references), and XML for LIMS integration. Software validation documentation (IQ/OQ/PQ protocols) is provided with each unit. Data encryption (AES-256) and local database redundancy ensure continuity during extended 180-day assays.

Applications

• Regulatory submission support for EN 13432, OK Compost INDUSTRIAL, and TÜV Austria certifications
• R&D screening of novel biopolymers (PLA, PHA, starch blends) and additive-modified conventional plastics
• Quantification of abiotic hydrolysis contribution via parallel abiotic control vessels (N₂ atmosphere)
• Validation of industrial compost facility feedstock acceptance criteria
• Academic research on microbial community dynamics during polymer depolymerization (compatible with post-assay DNA extraction from residual inoculum)
• Quality control of commercial compost amendments for biodegradation acceleration studies

FAQ

What standards does the DA18 directly support?
ISO 14855-1:2012, ASTM D5338–23, EN 13432:2000, and GB/T 32106–2015 (Chinese national standard).
Can the system measure disintegration separately from biodegradation?
Yes—residual mesh retention testing per ISO 14855-2 is supported via optional 2-mm sieve kits and gravimetric mass loss tracking.
Is inoculum preparation included in the system workflow?
No—the DA18 requires externally prepared, physicochemically characterized inoculum per ISO 14855 Annex A; however, SOP templates and validation checklists are supplied.
How is CO₂ quantification validated across vessels?
Each vessel’s NDIR sensor is individually calibrated before assay initiation using certified CO₂/N₂ gas mixtures (0–5% v/v), with drift correction applied daily via zero-gas (N₂) and span-gas (2.5% CO₂) injections.
Does the system meet cybersecurity requirements for regulated labs?
Yes—BioTrack™ v3.2 implements password complexity policies, session timeouts, and immutable electronic records aligned with EU Annex 11 and FDA 21 CFR Part 11 Subpart B.