Biodegradability in sewage

Biodegradation t,/2 Lil0—14 d for 0.001-1.0 qg/mL to biodegrade in sewage effluent lake water (Novick Alexander 1985 quoted, Muir 1991) ... 

The presence of the ester function in the molecular structure facilitates rapid biodegradation in sewage but also threatens its chemical stability on storage in the bottle and in the rinse, where it has to work at a slightly alkaline pH. At pH 6, for instance, the molecule is completely degraded after four weeks of storage at 50°C [6], Paradoxically the hydrolytic stability is much enhanced by keeping the pH below 3.5. 

Poly(vinyl alcohol) is made from poly(vinyl acetate) by hydrolysis. This polymer is water soluble and, as will be seen in Chapter 5, is one of the few synthetic water-soluble polymers to undergo rapid biodegradation in sewage systems. 

Linear alkylbenzenesulfonate showed no deleterious effect on agricultural crops exposed to this material (54,55). Kinetics of biodegradation have been studied in both wastewater treatment systems and natural degradation systems (48,57,58). Studies have concluded that linear alkylbenzenesulfonate does not pose a risk to the environment (50). Linear alkylbenzenesulfonate has a half-life of approximately one day in sewage sludge and natural water sources and a half-life of one to three weeks in soils. Aquatic environmental safety assessment has also shown that the material does not pose a hazard to the aquatic environment (56). 

Identification of a characteristic set of isomers with differently branched nonyl substitutions of poorly biodegradable nonylphenoxyacetic acid and nonylphen-oxyethoxy acetic acid in sewage effluents was identified with high-resolution gas chromatography/mass spectrometry (HRGS-MS) and quantitative determination was done with HPLC [245]. 

Simkins S, R Mukherjee, M Alexander (1986) Two approaches to modeling kinetics of biodegradation by growing cells and application of a two-compartment model for mineralization kinetics in sewage. Appl Environ Microbiol 51 1153-1160. 

The classification of antibiotics and the most popular antibiotic in its class are given in Table 6. Usually, the antibiotics excreted are partially metabolized and end up in sewage system. Some of the most commonly used antibiotics (e.g., sulfa drugs and p-lactam antibiotics) are difficult to biodegrade because of their complex structure, which protect them from the attack of wastewater biocoenosis. Moreover, the difficulty in biodegradation is also due to the lack of significant microorganism... 

Cheng HF, Chen SY, Lin JG (2000) Biodegradation of di-(2-ethylhexyl) phthalate in sewage sludge. Water Sci Technol 41 1-6... 

Baird et al. [40] utilized gas chromatography in his study of the biodegradability of chlorinated phenols in sewage sludge. 

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