The effectiveness of anaerobic digestion in removing estrogens and nonylphenol ethoxylates

Abstract

The fate and behaviour of two groups of endocrine disrupting chemicals, steroid estrogens and nonylphenol ethoxylates, have been evaluated during the anaerobic digestion of primary and mixed sewage sludge under mesophilic and thermophilic conditions. Digestion occurred over six retention times, in laboratory scale reactors, treating sludges collected from a sewage treatment works in the United Kingdom. It has been established that sludge concentrations of both groups of compounds demonstrated temporal variations and that concentrations in mixed sludge were influenced by the presence of waste activated sludge as a result of transformations during aerobic treatment. The biodegradation of total steroid estrogens was>50% during primary sludge digestion with lower removals observed for mixed sludge, which reflected bulk organic solids removal efficiencies. The removal of nonylphenol ethoxylates was greater in mixed sludge digestion (>58%) compared with primary sludge digestion and did not reflect bulk organic removal efficiencies. It is apparent that anaerobic digestion reduces the concentrations of these compounds, and would therefore be expected to confer a degree of protection against exposure and transfer of both groups of compounds to the receiving/re-use environment.

Sludge Retention Time as a Suitable Operational Parameter to Remove Both Estrogen and Nutrients in an Anaerobic–Anoxic–Aerobic Activated Sludge System

“…Sorption and biodegradation are important mechanisms for the removal of estrogens in biological wastewater treatment systems (Xu et al, 2008;McAdam et al, 2010;Gomes et al, 2011;Paterakis et al, 2012). Based on the measured sorption constants, Andersen et al (2005) have predicted that about 50%-75% of estrogens (estrone [E1], E2, and EE2) can be sorbed to the activated sludge in a sewage treatment plant.…”

Trace organic contaminants in biosolids: Impact of conventional wastewater and sludge processing technologies and emerging alternatives

“…NP n E where n=3-12) by 23%. Compared to Paterakis et al [119], Patureau et al [46] observed only a 20% increase in nonylphenol and nonylphenol monoethoxylate removal by increasing digestion temperature from mesophilic to thermophilic, probably because of different experimental conditions (e.g. SRT).…”

“…Studies concur that thermophilic digestion favours the removal of polycyclic aromatic hydrocarbons [44,120,121] especially those with higher molecular weight [120], but different trends are reported for hormones, nonylphenol/nonylphenol ethoxylates, and pharmaceuticals [8,47,51,98,116,119]. For instance, Paterakis et al [119] reported that increasing digester temperature from mesophilic (35±0.2 °C) to thermophilic (55±0.2 °C) enhanced the removal of estrone, but increased the bioconversion among hormones leading to a decrease in the removal of estriol and significant formation of 17β-estradiol. The same study also observed that thermophilic conditions enhanced the biodegradation rate of small nonylphenol ethoxylates (e.g.…”

“…Paterakis et al [119] reported that the removal of estrogen and nonylphenol ethoxylates from mixed sludge was 20-80% higher than that of primary sludge, but a clear explanation for this was not provided. conditions, but did not see significant difference in the removal of various hormones and pharmaceuticals due to SRT.…”

Aerobic treatment of selective serotonin reuptake inhibitors in landfill leachate

“…PPCPs have also been investigated under anaerobic digestion of sewage sludge [19][20][21][22], but SSRIs were not part of these investigations. Carballa et al [19] observed high removal efficiencies for antibiotics, natural estrogens, musk and naproxen, while for example carbamazepine showed no elimination under anaerobic treatment of sewage sludge.…”