Screening Material Breakdown

Biodegradation

Biodegradation is the natural process by which microorganisms break down organic substances into simpler compounds. Promoting biodegradability is essential for fostering a more sustainable and environmentally conscious approach to waste management and resource utilization. Although composting stands as one of the largest methods of biodegradation, it permeates diverse ecosystems, from the rich microbial communities of soil to the vast expanses of marine waters, and even the controlled environments of wastewater treatment plants and landfills. Tier 1 screening for biodegradation testing involves initial, rapid assessments to determine the potential biodegradability of a substance. These tests are designed to provide quick insights into whether further, more extensive testing is necessary. Understanding how biodegradation operates within each of these settings is crucial for implementing effective waste management strategies and safeguarding our planet's delicate balance.

Compost

Composting is like natural recycling, where organic waste transforms into nutrient-rich soil, creating a sustainable and eco-friendly way to manage food scraps and yard waste. As organic matter breaks down, temperatures rise, microbes multiply, and the compost pile transforms into a hotbed of microbial activity. Over time, a once-discarded banana peel or coffee grounds become a dense compost that enriches soil, nourishes plants, and fosters a thriving ecosystem. Common test standards that determine if a material is compostable are ASTM D6400 and EN 13432.

Marine Water

Ocean water biodegradation is the natural process wherein organic pollutants and debris in marine environments undergo breakdown via microbial activity. Vital players in this process include bacteria and fungi, which metabolize various organic compounds—ranging from oil spills to plastics and organic matter—into simpler forms, thereby reducing their harm to marine ecosystems. While ocean water biodegradation serves as a crucial mechanism in mitigating pollution impacts, its efficacy is influenced by factors such as water temperature, oxygen levels, and nutrient availability. Common test standards for evaluating biodegradation in marine environments include ASTM D6691 and ISO 14593.

Landfill

‍Landfill biodegradation occurs within municipal solid waste landfills, where organic materials undergo anaerobic decomposition in an oxygen-limited environment. Microbial communities within landfills break down organic waste, releasing methane and carbon dioxide gases as byproducts. Landfill biodegradation is a significant contributor to greenhouse gas emissions and landfill gas production. To mitigate environmental impacts, landfill operators implement gas collection systems to capture and utilize methane for energy generation, reducing greenhouse gas emissions and promoting sustainable waste management practices. ASTM D5511 and ISO 15985 are common test standards used to screen materials in landfill.

Soil

Soil biodegradation lies within the rich tapestry of terrestrial environments. Microbial communities within the soil matrix tirelessly work to decompose various materials, ranging from plant-based residues to biodegradable plastics. Bacteria, fungi, and other soil-dwelling organisms play pivotal roles in this process, converting complex materials into simpler forms that integrate seamlessly into the earth's nutrient cycle. Soil biodegradation is influenced by factors such as moisture content, temperature fluctuations, and nutrient availability. Notable test standards for evaluating material biodegradability in soil include ASTM D5988 and ISO 17556.

Wastewater

In the realm of wastewater treatment, biodegradation emerges as a cornerstone process. Within treatment facilities, diverse microbial communities work in concert to break down organic pollutants and contaminants present in wastewater streams. Bacteria, protozoa, and other microorganisms metabolize complex organic compounds, transforming them into simpler forms that can be safely reintegrated into the environment. Much like the vast expanses of ocean and the intricate networks of soil, wastewater biodegradation is governed by factors such as oxygen levels, nutrient availability, and treatment processes. Understanding the mechanisms of biodegradation in wastewater is crucial for designing effective treatment strategies and safeguarding water quality. Notable test standards for assessing biodegradation in wastewater include ASTM D5210 and ISO 11734, along with specific OECD test methods such as OECD 301 and OECD 302.

How the Micro-Oxymax Can Benefit Material Screening for Biodegradation

The Columbus Instruments’ Micro-Oxymax system is a highly adaptable general-purpose closed-circuit respirometer. The system monitors the concentration of gas contained within an enclosed head space into which the material being monitored is respiring. Periodic sensing of the gas concentration, along with an equally accurate measurement of the volume of the head space, allows calculations of incremental and accumulated values for consumption and production. The Micro-Oxymax design principle provides a sensing threshold near 2 x 10-7 liter per hour. The system can be configured for single or multiple gas sensing. Oxygen, Carbon Dioxide, Methane, and a variety of other gases can be sensed over specially selected ranges to meet almost any application.

The Micro-Oxymax is a modular system that can support testing biodegradability in all environments. An initial configuration for basic investigations can be expanded later to include additional gases and/or chambers. The software automates many aspects of the test with a single set of sensors to calibrate, it takes only a few minutes to begin a test. The system automatically compensates for changes in pressure and temperature and converts evolved carbon dioxide to STP for easy conversion into milligrams.