Development and Evaluation of an Online CO ₂ Evolution Test and a Multicomponent Biodegradation Test System

Abstract

Well-established biodegradation tests use biogenously evolved carbon dioxide (CO 2 ) as an analytical parameter to determine the ultimate biodegradability of substances. A newly developed analytical technique based on the continuous online measurement of conductivity showed its suitability over other techniques. It could be demonstrated that the method met all criteria of established biodegradation tests, gave continuous biodegradation curves, and was more reliable than other tests. In parallel experiments, only small variations in the biodegradation pattern occurred. When comparing the new online CO 2 method with existing CO 2 evolution tests, growth rates and lag periods were similar and only the final degree of biodegradation of aniline was slightly lower. A further test development was the unification and parallel measurement of all three important summary parameters for biodegradation-i.e., CO 2 evolution, determination of the biochemical oxygen demand (BOD), and removal of dissolved organic carbon (DOC)-in a multicomponent biodegradation test system (MCBTS). The practicability of this test method was demonstrated with aniline. This test system had advantages for poorly water-soluble and highly volatile compounds and allowed the determination of the carbon fraction integrated into biomass (heterotrophic yield). The integrated online measurements of CO 2 and BOD systems produced continuous degradation curves, which better met the stringent criteria of ready biodegradability (60% biodegradation in a 10-day window). Furthermore the data could be used to calculate maximal growth rates for the modeling of biodegradation processes.

The Study Of Metalworking Fluids Biodegradability By Indirect Measurement Of Bacterial Inoculum Respiration

“…The main purpose of this study was the establishment of a conductivity-based online CO2 evolution test. Authors in (9) state that this test fulfilled the requirements of standardized biodegradation tests and may serve as a basis for further development of biodegradation tests in different areas. In such a case, information obtained from three independent analytical parameters may lead to a better and more reliable prediction of biodegradability.…”

In-Situ Synthesis and Characterization of Biodegradable Estolides via Epoxidation from Canola Biodiesel

“…Biodegradability denotes the perseverance of prepared estolides in the ecosystem. Reported biodegradability studies were based on extent of the ultimate aerobic mineralization of the testing material to CO 2 in water [26,27]. The ratio of the biological oxygen demand to theoretical demand (BOD/ThOD) and total inorganic carbon dioxide production to theoretical inorganic carbon dioxide production (TIC/ThIC) was considered to analyze the biodegradation profile.…”

“…The ratio of the biological oxygen demand to theoretical demand (BOD/ThOD) and total inorganic carbon dioxide production to theoretical inorganic carbon dioxide production (TIC/ThIC) was considered to analyze the biodegradation profile. Through these tests, if the degradation exceeds 60% within 28 days, the test sample is considered as "readily biodegradable" [26]. In the current study, the biodegradability of the estolides was estimated by the bio-kinetic model to evaluate the effective composition of biodegradation based on the aromatic and ester fractions present in the estolides.…”

Standardized Methods for Water-Quality Assessment☆

“…For ultimate aerobic biodegradation (total mineralization), this can, in principle, be performed by measurement of DOC, oxygen consumption, or CO 2 formation. A comparison of CO 2 production or oxygen uptake with DOC removal as a measure of ultimate biodegradation is given in Reuschenbach et al (2003) and in Strotmann et al (2004). In order to capture the elimination that is caused by biodegradation, biodegradability tests comprise a blank control, a test with a reference substance, an inhibition control, an abiotic elimination control, and an adsorption control.…”