Alkanesulfonates biodegradation

Secondary alkanesulfonate biodegrades to form alcohols as intermediates. The longer chain homologs are more likely to adsorb to particulates and sludge and are slower to degrade. Alkanesulfonate has been reported in European sludges in the 0.01-0.1% concentration range (43,44). 

The byproduct is a stoichiometric amount of 60 wt % H2S04, which is used in the chemical industry. The wastewater (0.3 m3/100 kg active matter), which contains paraffin, oxidation products of the paraffin, alkanesulfonate, and sulfur dioxide, has a chemical oxygen demand (COD) of 1800 mg/L and is readily biodegradable (>95% after 7 days). The sulfur dioxide emission after repeated washing of the off-gas amounts to 0.5 g/100 kg active matter [6]. 

To put these data in perspective, it is important to point out that they merely imply an exhaustive biodegradation of secondary alkanesulfonates and do not represent monitoring results. 

Secondary alkanesulfonates are easily biodegradable under aerobic conditions but are less so in an anaerobic environment, a feature common to all sulfonates with the stable carbon-sulfur bond. The recent discussions on anaerobic biodegradation [103] should be put into perspective since in the sewage or deposition path a temporary anaerobic step quickly gives way to a stage where natural conditions, which are aerobic, prevail. Thus, anaerobic biodegradation... 

The primary biodegradation grades of secondary alkanesulfonates measured by different tests are distinctly above 90%. In the OECD Confirmatory Test (sewage treatment plant simulation test), the biodegradability is 99% (decrease in MBAS, the methylene blue active substance). 

In the modified OECD Screening Test (OECD 301E), which indicates complete degradation or elimination according to the German Chemical Substances Control Act, alkanesulfonates are biodegradable to 95% (decrease in DOC, the dissolved organic carbon). 

Some years ago, comparative investigations into the biodegradation of secondary alkanesulfonates using 14C-labeled preparations [106] and radiometric studies of the biodegradation of secondary alkanesulfonates in a sewage plant model [107] are published (Fig. 42). 

FIG. 42 Biodegradability of sodium stearate -- (U-I4C), alkanesulfonate Hostapur SAS — (U-I4C), and LAS (ring-tagged U-l4C) determined in a Hach apparatus (BOD5) and represented as the evolution of I4C02 evolution with time. 

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