Composting Chemistry

Willow Ridge Plastics - PDQ-H additive (Plastic A) and Ecosafe Plastic - Totally Degradable Plastic Additives (TDPA) additive (Plastic B). 

Mater-Bi Novamont (MB) and Environmental Product Inc. (EPI). Cellulose filter papers (CFP) were used as a positive control. 

Biodegradability was assessed under aerobic and anaerobic conditions. For aerobic conditions, organic fractions of municipal solid wastes were composted. For the anaerobic process, anaerobic inoculum from a wastewater treatment plant was used. 

Cumulative CO2 evolution for Plastic A was much higher than that for Plastic B. Plastic A therefore showed a higher level of biodegradation in terms of CO2 evolution than Plastic B. 

Another experiment was undertaken to observe any physical change of Plastics A and B as compared to a reference plastic, namely, compostable plastic bag (Mater-Bi product Plastic C). Thermophilic temperatures were obtained for about 3-5 days of composting. 

---

Environmental applications of FIFFF have been carefully collected in a review by Gimbert et al. [35]. Separations of nanoparticles belong to the FIFFF tradition and this sector has recently found new, fully deserved impulse for microparticle separations. The FIFFF technique has been applied to analyze humic material and submicron Fe colloids. Coupled with ICP-MS, FIFFF has been applied to detect the major and trace element chemistry of aquatic colloids in groundwaters and to determine the trace element distribution in soil and compost-derived humic and colloidal fractions in municipal wastewater. Recently, the ICP-AES has also been proposed as a specific detector for FIFFF to analyze inorganic nanoparticles (Figure 12.12). 

Veeken, A., Nierop, K., De Wilde, V., and Hamelers, B. (2000). Characterisation of NaOH-extracted humic acids during composting of a biowaste. Bioresource Technol. 72, 33 U. Wilson, M. A. (1987). NMR Techniques and Applications in Geochemistry and Soil Chemistry. Pergamon Press, Oxford, UK. 

Griest, W.H., Tyndall, R.L., Stewart, A.J., Caton, J.E., Vass, A.A., Ho, C.H. and Caldwell, W.M. (1995) Chemical characterization and toxicological testing of windrow composts from explosives-contaminated sediments, Environmental Toxicology and Chemistry 14, 51-59. 

The environment is an important factor affecting the rate and degree of biodegradation of polymer substrates. The other key aspects determining biodegradability are related to the chemical composition of the polymer. The polymer chemistry governs the chemical and physical properties of the material and its interaction with the physical environment, which in turn affects the material s compostability with particular degradation mechanisms. 

Certain materials, such as compost, wood ashes, sewage, and animed wastes, were eventually discovered to be beneficial to crop growth. But basic research concerning the roles played by various chemical elements in the mineral nutrition of plants could not be initiated until the fundamentals of chemistry were firmly established. 

Van der Sloot HA (2002) Hartnonisation of leach-ing/extraction procedures for sludge, compost, soil and sediment analyses. In Quevauviller Ph, ed. Methodologies in Soil and Sediment Fractionation Studies, Chapter 7, pp. 142—174. The Royal Society of Chemistry, Cambridge, UK... 

Ho, K.-L.G. and Pometto, A.L. Ill (1999) Temperature effects on soil mineralization of polylactic acid plastic in laboratory respirometers. Journal of Environmental Polymer Degradation, 1, 101-108. Buchanan, C.M., Dorschel, D.D., Gardner, R.M. et al. (1995) Biodegradation of cellulose esters Composting of cellulose ester-diluent mixture. Journal of Macromolecular Science, Part A Pure and Applied Chemistry, A32,683-697. 

Terzano, R., Z. A. Chami, B. Vekemans, K. Janssens, T. Miano, and P. Ruggiero. 2008. Zinc distribution and speciation within rocket plants (Eruca vesicaria L. Cavaheri) grown on a polluted soU amended with compost as determined by XRF microtomography and Micro-XANES. Journal of Agricultural and Food Chemistry 56, no. 9 3222-3231. doi 10.1021/jf073304e. 

Chemical recycling should be considered in any waste management system for PLA, since from a life-cycle perspective, it represents a relatively small amount of net chemistry compared to the C02-to-PLA cycles for incineration or composting. Simple hydrolysis can turn waste PLA back into fully functional lactic acid, at potentially low economic and environmental cost, contributing to the total sustainability of PLA production. 

The second test procedure for EN 13432 standard specifies that a satisfactory rate of biodegradation of the plastic material is under industrial composting conditions of at least 58°C and 50% moisture for 26 weeks, that is, more than 90% of the carbon in the original plastic sample is converted into CO2 as measured by a CO2 respirometer or wet chemistry methods. The details of the test procedures are listed in EN 14046 or ISO 14855 test method. 

The development of national and international norms on biodegradability proved not to be an easy task as it necessitated the bringing together of biological processes (e.g., composting) in all their complexity, on the one hand, and polymer chemistry on the other. Yet, over the last 20 years significant progress has been made and several standards and norms have been developed and will be further elaborated. 

---