Removal of typical pharmaceutically active compounds in sewage sludge using mesophilic and thermophilic anaerobic digestion processes

Abstract

The removal of four pharmaceutically active compounds, i.e., anti-inflammatory painkiller diclofenac (DCF), lipid-regulating agent clofibric acid (CFA), epilepsy drugs carbamazepine (CBM), and broad-spectrum anti-bacterial agent triclosan (TCS), present in sewage sludge was investigated using anaerobic digestion processes in the mesophilic and thermophilic modes. Sludge retention times (SRTs) were set at 10, 15, and 20 days, respectively, for the mesophilic mode and 7, 15, and 20 days, respectively, for the thermophilic mode. The effective isolation and purification pre-treatment to extract the target compounds from the sewage sludge samples were firstly established, followed by gas chromatographymass spectrometer analysis to identify and quantify them. The removal efficiencies of the target compounds could be raised to a certain extent with the increase on SRTs, especially under the mesophilic condition. The removal of CFA and TCS under thermophilic condition hardly varied when the SRTs were above 15 days. All the compounds could be partly removed from the sewage sludge under the two temperature conditions, particularly TCS that was reduced by about 74 %. Besides, CFA, firstly reported in this study, could be reduced by maximal 65 %. On the whole, the thermophilic mode was more conducive to the removal of CBM and TCS, but did not have a noticeable effect on the removal of CFA. Furthermore, DCF could be better removed in the mesophilic mode. In addition, NH 3 -N accumulation in this measured range might positively affect the removal of the selected compounds, particularly in the mesophilic mode.

Removal and reduction of selected organic micro-pollutants in effluent sewage by the ozone-based oxidation processes

“…The samples were intermediately added a small amount of sodium sulfite solution to extinguish the oxidation reaction. Then, the 50-mL samples were pre-treated through solid phase extraction (SPE), and derivatization for gas chromatography-mass spectrometry (GC/MS) analysis using the methods described by Zhou et al [18,24]. And the rest 50-mL samples were used for the other measurements of water quality.…”

Effects of zero-valent iron and enzymes on the anaerobic co-digestion of sewage sludge and corn silage

“…The inoculum sludge 20 dm 3 collected from the anaerobic digester of our lab was pumped into each digester. The procedure for the start-up has been described elsewhere [12]. Following the start-up, the digesters were fed with the co-substrates of sludge and the corn silage (the ratio of sludge and corn silage weight was adjusted to 2:1) based on the previous results [13].…”

Assessing the occurrence of pharmaceuticals and antibiotic resistance genes during the anaerobic treatment of slaughterhouse wastewater at different temperatures

“…In fact, most of the studies concluded that a temperature increase favors the biodegradation of some PhACs and reduce the removal of others (Carballa et al, 2007;Davidsson et al, 2014;Gros et al, 2020;Zhou et al, 2015). Related to antibiotic resistance genes (ARGs), literature is even more contradictory, since some studies recommend thermophilic digestion for ARGs removal (Oliver et al, 2020;Zou et al, 2020) and others do not (Huang et al, 2019).…”