Appl Microbiol Biotechnol DOI 10.1007/s00253-015-6667-1
ENVIRONMENTAL BIOTECHNOLOGY
Domestic wastewater treatment in a novel sequencing batch biofilm filter Bin Ji 1 & Li Wei 2 & Dan Chen 1 & Hongyu Wang 1 & Zhenhua Li 3 & Kai Yang 1
Received: 4 March 2015 / Revised: 19 April 2015 / Accepted: 1 May 2015 # Springer-Verlag Berlin Heidelberg 2015
Abstract Biological treatment of domestic sewage low C/N ratio was accomplished in a pilot-scale sequencing batch biofilm filter (SBBF). The novel hybrid bioreactor consisted of bio-band in the upper and anthracite filter media in the bottom, which combined a sequencing batch biofilm reactor (SBBR) with a biological filter. The average removal efficiency values of chemical oxygen demand (COD), ammonium nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) were 89.4, 83.3, 62.9, and 48.7 %, respectively. A 454pyrosequencing technology was employed to investigate the microbial communities of the influent (J1) and the biofilm (J2) on the bio-band on day 40. Pyrosequencing analysis of the 16S rRNA gene revealed the community of the biofilm c o n s i s t e d o f G a m m a p ro t e o b a c t e r i a ( 4 8 . 6 % ) , Planctomycetacia (18.0 %), Alphaproteobacteria (13.7 %), C l o s t r i d i a ( 9 . 6 % ) , D e s u l f o n a t ro n u m ( 1 8 . 5 % ) , Actinobacteria (1.9 %), and Bacilli (1.7 %), accounting for 93.6 % of total operational taxonomic units at genera level. Acinetobacter tjernbergiae and Acinetobacter lwoffii were the most abundant species, suggesting that denitrifying phosphorus removal was achieved in the SBBF.
* Hongyu Wang [email protected] * Kai Yang [email protected] 1
School of Civil Engineering, Wuhan University, Wuhan 430072, China
2
State Key Lab of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China
3
Department of Environmental Science and Engineering, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430072, China
Keywords Wastewater treatment . Denitrifying phosphorus removal . Pyrosequencing . Sequencing batch biofilm filter
Introduction Biological method plays an indispensable role in treating municipal wastewater, mainly including an activated sludge process and a biofilm process. As one of the important and widely used activated sludge processes, a sequencing batch reactor can achieve nitrogen and phosphorus removal in a single reactor using alternating anoxic and aerobic conditions. The sequencing batch biofilm reactor is the modification of the sequencing batch reactor by adding media packed in the reactor body. The nutrient removal efficiency is increased due to its greater biomass concentration. Moreover, the sequencing batch biofilm reactor (SBBR) offers an anoxic microzone in the inner layers of the biofilm during the aeration phase. Therefore, simultaneous nitrification and denitrification (SND) can be achieved and denitrifying phosphorus removal can occur in the anoxic microzone (Choi et al. 2008). Accordingly, the SBBR has been adopted to remove many kinds of wastewater. However, a long hydraulic residence time (HRT) of approximately 15 h is needed with quite high effluent suspended solids (SS) of around 45 mg L−1 for SBBR (Feng et al. 2008; Sarti et al. 2007). As one of the biofilm processes, a biological filter is easy to manage which can remove organic matters and suspended solids simultaneously (Kim et al. 2008). A biological aerated filter can be used as an additional treatment in drinking water treatment plant systems for simultaneous chemical oxygen demand (COD), ammonium (NH4+-N), and manganese removal (Hasan et al. 2011). But for wastewater treatment, a three- or four-stage biological aerated filter system is
Appl Microbiol Biotechnol
necessary to enhance nitrogen removal at the bench scale (Ryu et al. 2008, 2014). It is of great significance to gain a detailed insight into the microbial community and explore its relation with the system performance. PCR-based 454 pyrosequencing has recently been applied to investigate the microbial populations of activated sludge in different WWTPs as well as in full-scale bioreactors (Sanchez et al. 2013; Zhang et al. 2012). Pyrosequencing does not require subcloning or handling of individual clones and provides cost-effective, rapid, and highly parallel sequencing of large numbers of DNA fragments from complex samples or transcriptomes, which is particularly suited to microbial ecology studies (Roh et al. 2010). Over thousands of operational taxonomic units (OTUs) could be identified. It provides enough sequencing depth to cover the complex microbial communities (Shendure and Ji 2008). This technology has been effectively used to disclose the relations between the microbial community and pollutant removal in various wastewater treatment processes. For example, the bacterial community in a laboratory-scale nitrification reactor was analyzed (Ye et al. 2011). Composition and dynamics of a microbial community in a zeolite biofilter-membrane bioreactor treating coking wastewater were investigated (Zhu et al. 2013). In this paper, a sequencing batch biofilm filter (SBBF) as a novel hybrid process by combining SBBR and biological filters to treat domestic sewage has been evaluated. Removal efficiencies of organic matters (OM), nitrogen (N), and phosphorus (P) were constantly tested. PCR-based 454 pyrosequencing was applied to determine the bacterial component of the influent and the biofilm in the bioreactor.
control cabinet, raw water was pumped into the reactor, mixing and standing for 30 min. The aeration time was 70 min. After settling for 10 min, the effluent was discharged from the SBBF. The parameters were controlled as follows: dissolved oxygen (DO) concentration of upper reactor for aeration was 2–3 mg L−1, the initial filter speed was 5 m h−1, HRT was 10 h (2 h each cycle), and sludge retention time (SRT) was 70 days. The reactor was operated outdoor with the temperature at 16–25 °C. The reactor was inoculated with about 30 L activated sludge of the plant with a concentration of 3000 mg L−1. Then, the whole reactor was submerged into raw water and aerated for 1 h to achieve complete mixing. After conditioned for 10 h, wastewater in the reactor was output entirely. Fresh influent was continuously injected into the reactor, accompanied by the discharge line opened to maintain a steady flow. Aeration was applied consistently from the bottom of the reactor. This process continued for about 20 days until the attached biofilm formed on bio-band by microscopic examination. Then, the reactor was operated periodically as mentioned above. After about 15 days, the removal of COD and TN was stabilized. Backwashing procedure was as follows: air scour for 2 min, combined air scour and water backwash for 2 min, and water backwash for 5 min. The backwash air and water velocities were 16 and 5 L m−2 s−1, respectively. The average operation before a backwash was 3 days, and the maximum duration was 7 days. After backwashing, excess sludge or detached biofilm was discharged from the SBBF in order to achieve the desired SRT of about 70 days. Analysis methods
Materials and methods Reactor operation As shown in Fig. 1, the reactor is a 4.0-m high organic glass column, with a 23.5-cm inner diameter, below which was a long handle filter nozzle in the middle of a retainer plate with dozens of holes with a diameter of 0.9 mm. The upper layer immobilized a length of 1720-mm bio-band (Keliang Biotechnology Co. Ltd, Wuhan 430070, China; 4 mm thick, 40 mm wide, 800 kg m−3 density, 30,000 m2 m−3 specific), which was made up of polymer composite materials. The lower layer was filled with a depth of 1.1 m anthracite filter media (1- to 2-mm diameter, 1500 kg m−3 density, nonuniform coefficient K80 =d80/d10
ENVIRONMENTAL BIOTECHNOLOGY
Domestic wastewater treatment in a novel sequencing batch biofilm filter Bin Ji 1 & Li Wei 2 & Dan Chen 1 & Hongyu Wang 1 & Zhenhua Li 3 & Kai Yang 1
Received: 4 March 2015 / Revised: 19 April 2015 / Accepted: 1 May 2015 # Springer-Verlag Berlin Heidelberg 2015
Abstract Biological treatment of domestic sewage low C/N ratio was accomplished in a pilot-scale sequencing batch biofilm filter (SBBF). The novel hybrid bioreactor consisted of bio-band in the upper and anthracite filter media in the bottom, which combined a sequencing batch biofilm reactor (SBBR) with a biological filter. The average removal efficiency values of chemical oxygen demand (COD), ammonium nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) were 89.4, 83.3, 62.9, and 48.7 %, respectively. A 454pyrosequencing technology was employed to investigate the microbial communities of the influent (J1) and the biofilm (J2) on the bio-band on day 40. Pyrosequencing analysis of the 16S rRNA gene revealed the community of the biofilm c o n s i s t e d o f G a m m a p ro t e o b a c t e r i a ( 4 8 . 6 % ) , Planctomycetacia (18.0 %), Alphaproteobacteria (13.7 %), C l o s t r i d i a ( 9 . 6 % ) , D e s u l f o n a t ro n u m ( 1 8 . 5 % ) , Actinobacteria (1.9 %), and Bacilli (1.7 %), accounting for 93.6 % of total operational taxonomic units at genera level. Acinetobacter tjernbergiae and Acinetobacter lwoffii were the most abundant species, suggesting that denitrifying phosphorus removal was achieved in the SBBF.
* Hongyu Wang [email protected] * Kai Yang [email protected] 1
School of Civil Engineering, Wuhan University, Wuhan 430072, China
2
State Key Lab of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China
3
Department of Environmental Science and Engineering, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430072, China
Keywords Wastewater treatment . Denitrifying phosphorus removal . Pyrosequencing . Sequencing batch biofilm filter
Introduction Biological method plays an indispensable role in treating municipal wastewater, mainly including an activated sludge process and a biofilm process. As one of the important and widely used activated sludge processes, a sequencing batch reactor can achieve nitrogen and phosphorus removal in a single reactor using alternating anoxic and aerobic conditions. The sequencing batch biofilm reactor is the modification of the sequencing batch reactor by adding media packed in the reactor body. The nutrient removal efficiency is increased due to its greater biomass concentration. Moreover, the sequencing batch biofilm reactor (SBBR) offers an anoxic microzone in the inner layers of the biofilm during the aeration phase. Therefore, simultaneous nitrification and denitrification (SND) can be achieved and denitrifying phosphorus removal can occur in the anoxic microzone (Choi et al. 2008). Accordingly, the SBBR has been adopted to remove many kinds of wastewater. However, a long hydraulic residence time (HRT) of approximately 15 h is needed with quite high effluent suspended solids (SS) of around 45 mg L−1 for SBBR (Feng et al. 2008; Sarti et al. 2007). As one of the biofilm processes, a biological filter is easy to manage which can remove organic matters and suspended solids simultaneously (Kim et al. 2008). A biological aerated filter can be used as an additional treatment in drinking water treatment plant systems for simultaneous chemical oxygen demand (COD), ammonium (NH4+-N), and manganese removal (Hasan et al. 2011). But for wastewater treatment, a three- or four-stage biological aerated filter system is
Appl Microbiol Biotechnol
necessary to enhance nitrogen removal at the bench scale (Ryu et al. 2008, 2014). It is of great significance to gain a detailed insight into the microbial community and explore its relation with the system performance. PCR-based 454 pyrosequencing has recently been applied to investigate the microbial populations of activated sludge in different WWTPs as well as in full-scale bioreactors (Sanchez et al. 2013; Zhang et al. 2012). Pyrosequencing does not require subcloning or handling of individual clones and provides cost-effective, rapid, and highly parallel sequencing of large numbers of DNA fragments from complex samples or transcriptomes, which is particularly suited to microbial ecology studies (Roh et al. 2010). Over thousands of operational taxonomic units (OTUs) could be identified. It provides enough sequencing depth to cover the complex microbial communities (Shendure and Ji 2008). This technology has been effectively used to disclose the relations between the microbial community and pollutant removal in various wastewater treatment processes. For example, the bacterial community in a laboratory-scale nitrification reactor was analyzed (Ye et al. 2011). Composition and dynamics of a microbial community in a zeolite biofilter-membrane bioreactor treating coking wastewater were investigated (Zhu et al. 2013). In this paper, a sequencing batch biofilm filter (SBBF) as a novel hybrid process by combining SBBR and biological filters to treat domestic sewage has been evaluated. Removal efficiencies of organic matters (OM), nitrogen (N), and phosphorus (P) were constantly tested. PCR-based 454 pyrosequencing was applied to determine the bacterial component of the influent and the biofilm in the bioreactor.
control cabinet, raw water was pumped into the reactor, mixing and standing for 30 min. The aeration time was 70 min. After settling for 10 min, the effluent was discharged from the SBBF. The parameters were controlled as follows: dissolved oxygen (DO) concentration of upper reactor for aeration was 2–3 mg L−1, the initial filter speed was 5 m h−1, HRT was 10 h (2 h each cycle), and sludge retention time (SRT) was 70 days. The reactor was operated outdoor with the temperature at 16–25 °C. The reactor was inoculated with about 30 L activated sludge of the plant with a concentration of 3000 mg L−1. Then, the whole reactor was submerged into raw water and aerated for 1 h to achieve complete mixing. After conditioned for 10 h, wastewater in the reactor was output entirely. Fresh influent was continuously injected into the reactor, accompanied by the discharge line opened to maintain a steady flow. Aeration was applied consistently from the bottom of the reactor. This process continued for about 20 days until the attached biofilm formed on bio-band by microscopic examination. Then, the reactor was operated periodically as mentioned above. After about 15 days, the removal of COD and TN was stabilized. Backwashing procedure was as follows: air scour for 2 min, combined air scour and water backwash for 2 min, and water backwash for 5 min. The backwash air and water velocities were 16 and 5 L m−2 s−1, respectively. The average operation before a backwash was 3 days, and the maximum duration was 7 days. After backwashing, excess sludge or detached biofilm was discharged from the SBBF in order to achieve the desired SRT of about 70 days. Analysis methods
Materials and methods Reactor operation As shown in Fig. 1, the reactor is a 4.0-m high organic glass column, with a 23.5-cm inner diameter, below which was a long handle filter nozzle in the middle of a retainer plate with dozens of holes with a diameter of 0.9 mm. The upper layer immobilized a length of 1720-mm bio-band (Keliang Biotechnology Co. Ltd, Wuhan 430070, China; 4 mm thick, 40 mm wide, 800 kg m−3 density, 30,000 m2 m−3 specific), which was made up of polymer composite materials. The lower layer was filled with a depth of 1.1 m anthracite filter media (1- to 2-mm diameter, 1500 kg m−3 density, nonuniform coefficient K80 =d80/d10
