The removal of ammonia-nitrogen and degradation of 17alpha-ethynylestradiol and mestranol using partial fixed bed continuous reactor (PFBR) and moving bed continuous reactor (MBBR).

Effective treatment o f wastewater is an important process in reducing the environmental impact o f industry and human activity. Although conventional water treatment systems can adequately remove the principle components o f waste (i.e. substances that can be represented the majority o f biological and chemical oxygen demand) several materials are poorly or slowly removed. Tertiary treatment polishing processes are therefore required to remove these contaminants to ensure complete wastewater treatment. This thesis reports investigations made using film reactors that are used to remove recalcitrant materials such as ammonianitrogen and endocrine disrupters that although present in low concentrations, if left untreated can have a strong impact on the environment. Film reactors potentially offer several process advantages over conventional activated sludge treatments systems as they allow very long residence time and contact with high concentrations o f fixed microbes with the low concentrations o f pollutants so enhancing kinetic performance and efficiency o f the process. Two reactor configurations, a partial fixed bed (PFBR) and moving bed biofilm reactors (MBBR) were investigated. A thirty liter reactor with a working volume o f 16 liters was constructed and contained fixed microbial films on either free suspended or fixed beds plastic packing (K2 AnoxKaldnes). The investigation o f ammonia nitrogen oxidation showed that after a suitable acclimation period ( 2 weeks) that ammonia was oxidise rapidly reducing the feed concentrations o f 35 mg/L to < 2 mg/L in the effluent. To assess the performance for ammonia nitrogen removal the reactors operated for long periods (up to 3 months) with continuous feed using the reactor in either PFBR or M BBR modes in addition o f 17a ethynylestradiol (EE2) and mestranol (MeEE2), the endocrine disrupting compounds commonly found in municipal wastewater. These substances is derived from a synthetic hormones if found in the natural environment can reduced the productivity o f the fish as this can cause feminization in aquatic organisms with disastrous consequences on fish populations. The M BBR and PFBR systems were used to investigate the co-metabolism o f ammonia nitrogen, 17a ethynylestradiol (EE2) and mestranol from model waste water feed containing 35 mg/L o f ammonia nitrogen and 100 pg/L o f 17a ethynylestradiol (EE2) and mestranol (MeEE2). A kinetic analysis o f the systems were made and for the PFBR reactor, the specific growth rate, pmax o f 7.092 d ' 1 w ith saturation constants, Ks o f 1.574 mg/L. The kinetic analysis for the M BBR system was 6.329 d ' 1 for the pmax with the Ks o f 0.652 mg/L. When the PFBR was used removal o f EE2 represents < 90% removal and MeEE2 represents < 70% removal. With the M BBR > 90% EE2 was removed and > 70% MeEE2 was removed. M BBR were shown to be more effective and efficient in removing ammonia nitrogen reducing the levels under good conditions to < 2 mg/L while the PFBR could also achieve 2 mg/L. The M BBR system was also more competent in the removal o f 17a ethynylestradiol (EE2) and mestranol compared to PFBR. This work demonstrates that there are considerable advantages to using thin film reactors as polishing step for the tertiary treatment o f waste waters when to compared to other processes in reducing the inorganic pollutants as endocrine disrupting compounds. The significance o f these results is discussed in this context.