The effect of biocarrier usage on pentachlorophenol (PCP) and di (2ethylhexyl) phthalate (DEHP) removal efficiency from textile wastewater in sequencing batch reactor

Micropollutants are a small amount in the environment but can cause significant effects. They can be toxic, carcinogen and endocrine disorder effect on aquatic ecosystems. European Union Water Firework Directive determined 45 priority pollutants. In this context, within the scope of the Regulation on Surface Water Quality revised in 2016, an Environmental Quality Standard (EQS) has been established for micropollutants determined for river/lake and coastal, transitional waters in Turkey. Lab scale 5L sequencing batch reactor (SBR) and biocarrier addition on SBR (SBBR) systems were fed real wastewater, which was obtained from Demirtaş Organized Zone. SBR and SBBR were operated for a total reaction time 20 hr. The removal rate of conventional pollutants and also DEHP, which used as a plasticiser and endocrine disorder character, PCP, which is used as a pesticide and toxic character, was investigated in this thesis. In the treatability studies carried out, it was aimed to determine the effect of operation conditions (anaerobic-aerobic cycle times, HRT, and SRT) and biocarrier on treatment performance and to determine optimum operating conditions. Conventional pollutants (COD, TSS, colour, MLSS) and selected micropollutants analysed according to standard methods daily to get treatment efficiency and operational performance. For PCP and DEHP analysis, samples, which were obtained from treated water, mixed liquid, biocarier measured by GC-MS and their concentrations were determined. Firstly, to determine the aeration effect, a study carried these operation conditions; 4 hr. anaerobic-16 hr. aerobic (SET1), 8 hr. anaerobic-12 hr. aerobic (SET 2), 12 hr. anaerobic-8 hr. aerobic, (SET 3), 16 hr. anaerobic-4 hr. aerobic (SET 4). It has been observed that the increase in aeration time increases DEHP removal for both processes, but higher removal efficiencies are achieved in SBBR. In contrast, a variation of anaerobic-aerobic cycle times on PCP removal has a more limited effect compared to DEHP. HRT 36, 48 and 60 hr. SRT (15 days) and aeration (4 hr. anaerobic / 16 hr. aerobic) were kept constant. When HRT increased DEHP, and PCP removal rate increased for SBR and SBBR. To determine the sludge age effect, the systems were studied for SRT, 10, 15 and 20 days and other variables were kept constant. Main removal mechanisms for DEHP and PCP were sorption to sludge and biodegradation; however, volatilization was negligible due to low Henry Constants. The maximum removal rate for selected micropollutants was 4 hr. anaerobic-16 hr. aerobic, HRT 60 hr. and SRT 15 day operating conditions, while DEHP removal efficiency was 83% and 61.9% for AKBR and AKR, respectively and PCP removal efficiency was 75.5% and 49.9% respectively. Keywords: SBR, SBBR, biological treatment, DEHP, PCP, micropollutant