w a t e r r e s e a r c h 6 3 ( 2 0 1 4 ) 1 9 0 e1 9 8
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/watres
Treatment of high strength pharmaceutical wastewaters in a Thermophilic Aerobic Membrane Reactor (TAMR) a,*, G. Bertanza b M.C. Collivignarelli a, A. Abba a
Department of Civil Engineering and Architectural Engineering, University of Pavia, Via Ferrata 1, 27100 Pavia, Italy b Department of Civil, Environmental, Architectural Engineering, and Mathematics, University of Brescia, Via Branze 43, 25123 Brescia, Italy
article info
abstract
Article history:
In the present work we studied the thermophilic biological treatability of high strength
Received 7 March 2014
liquid wastes from a pharmaceutical industry (rich in organic matter e COD: Chemical
Received in revised form
Oxygen Demand, nutrients and salinity). Different mixtures (with concentrations of COD,
23 May 2014
phosphorus and chloride up to 57,000 mg L1, 2000 mg L1 and 9000 mg L1, respectively)
Accepted 16 June 2014
were tested. The pilot plant used in this work was designed and built with dimensions
Available online 24 June 2014
comparable to a semi-industrial unit. The results are therefore representative for full-scale applications. During four months of experimentation, the pilot plant (TAMR e Thermo-
Keywords:
philic Aerobic Membrane Reactor) was operated at 49 ± 1 C and the organic loading rate
Thermophilic Aerobic Membrane
was 1.5e5.5 kgCOD m3 d1 with a hydraulic retention time of 5e10 days.
Reactor (TAMR)
Main results are the following: a) extremely high COD removal rate (up to 98%); b) very
Ultrafiltration
low sludge production (~0.016 kgVSS produced kg1 COD removed); c) suitability as a pre-treatment
Salinity
to a conventional (e.g. activated sludge) biological treatment (the studied pharmaceutical
Sludge minimization
industrial wastewaters are discharged into the sewer system for final polishing in a centralized municipal wastewater treatment plant) and d) high phosphorus removal (up to 99%). © 2014 Elsevier Ltd. All rights reserved.
1.
Introduction
Thermophilic aerobic biological systems work at temperatures higher than 45 C. These conditions can be reached, at reasonable costs, feeding preheated wastewaters with high organic load and providing an adequate thermal insulation of the reactor. Thermophilic processes (TPPs) ensure high removal yields of organic matter (Abeynayaka and
* Corresponding author. ). E-mail address: [email protected] (A. Abba http://dx.doi.org/10.1016/j.watres.2014.06.018 0043-1354/© 2014 Elsevier Ltd. All rights reserved.
Visvanathan, 2011a) and are suited for treatment of wastewaters with high salinity or with the presence of hazardous compounds (Rozich and Colvin, 1997). They can also reduce the content of metals, particularly iron (Slobodkin, 2005). Furthermore, thermophilic treatments show high removal kinetics of biodegradable substrates, about 3e10 times higher than those measured in mesophilic conditions (Lapara and Alleman, 1999). Sludge production is very low compared to mesophilic processes: about 0.05e0.3 kgTSS produced per
191
w a t e r r e s e a r c h 6 3 ( 2 0 1 4 ) 1 9 0 e1 9 8
kgCOD removed (Kurian et al., 2005; Suvilampi and Rintala, 2003). TPPs are able to remove pathogens due to high process temperature (Lapara and Alleman, 1999; Juteau, 2006). Other important advantages of biological thermophilic systems concern heat recovery (Lapara and Alleman, 1999), high removal yields for synthetic molecules (Lapara et al., 2001), flexibility and stability of the process (Lapara and Alleman, 1999; Tripathi and Allen, 1999; Morgan-Sagastume and Allen, 2003). From the other hand, a serious drawback of TPPs consists in the poor sludge settleability (C ¸ etin and Su¨ru¨cu¨, 1990; Barr et al., 1996; Tripathi and Allen, 1999; Lapara and Alleman, 1999). The reason of this is the low ability of thermophilic biomass to form flocs (Lapara and Alleman, 1999): floc forming bacteria hardly grow in a non-ideal environment such as a biological reactor with high temperature. At last, Abeynayaka and Visvanathan (2011a), Kurian and Nakhla (2006) and Kurian et al. (2005) have shown that nitrification in thermophilic treatments does not occur, as a result of low concentration of the nitrifying bacteria (Lapara and Alleman, 1999); only in some cases very slow nitrification rates were observed (Abeynayaka and Visvanathan, 2011b). In order to overcome the disadvantage of the poor sludge sedimentation, a proper solution is the implementation of a Membrane Bioreactor (MBR) system. In particular, using a MBR thermophilic system with pure oxygen, it is possible to operate with higher concentration of biomass (higher than 50 kgTSS m3), resulting in a drastic reduction of the reactor volume and a smaller aeration tank. The undersized aeration tank allows an easy management of the odorous emissions. Based on the new ordinance (regulation) of the European Water Framework Directive (EWFD), in order to achieve the “good quality” for all EU waters (including surface and groundwater) by 2015 (European Commission, 2012), it is important to obtain low concentrations of COD. This represents a challenge due to the presence of the biorefractory fraction, which requires expensive chemical-physical treatments for its transformation and/or removal. It is also
essential the elimination of nutrients (nitrogen and phosphorus). Additionally, since phosphorus is a depleting resource, in the last decade the attention has been focused on the issue of recovery (de-Bashan and Bashan, 2004; Shu et al., 2006; Vaccari and Strigul, 2011). The technology studied in this work, based on a Thermophilic Aerobic Membrane Reactore TAMR, allows an increase of wastewater biodegradability under mesophilic conditions. The downstream polishing in a centralized municipal wastewater treatment plant is therefore more effective in reducing recalcitrant COD. Moreover, phosphorus is precipitated as hydroxyapatite. The experimentation was conducted with a pilot scale (V ¼ 1 m3) TAMR, fed with high strength liquid wastes derived from a pharmaceutical factory. The choice to treat these type of wastewaters with a TPP derived from monitoring for ten years of a full-scale TAMR plant that treats a wide range of liquid wastes, including those from the pharmaceutical industry (Bertanza et al., 2010).
2.
Methods
This experimental research was carried out in a pharmaceutical company that produces an effluent which was treated by a TAMR pilot plant. The company produces chiral materials (high-value amino acids) as starting materials and/or key intermediates for the pharmaceutical and biotech community. It also manufactures materials for the nutraceutical and cosmetic industries and related compounds classified as Active Pharmaceutical Ingredients (APIs).
2.1.
Wastewater characteristics
Four different types of liquid waste were tested (see Table 1). The liquid waste 1 (L.W. 1) has COD concentration of 1,000,000 mg L1 and a total phosphorus (TP) concentration higher than 60,000 mg L1. The liquid waste 2 (L.W. 2) shows
Table 1 e Chemical characteristics of tested liquid wastes. Parameter
pH Electrical conductivity COD NH4 þ N NO2 N NO3 TN TP Chloride Sulphate Toluene Methylene chloride Acetone Ethanol Acetic acid n.m. ¼ not measured.
Liquid wastes e mS cm1 mg L1 mg L1 mg L1 mg L1 mg L1 mg L1 mg L1 mg L1 mg L1 mg L1 mg L1 mg L1 %
L.W. 1
L.W. 2
L.W. 3
L.W. 4
2.45 n.m. 1,000,000
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/watres
Treatment of high strength pharmaceutical wastewaters in a Thermophilic Aerobic Membrane Reactor (TAMR) a,*, G. Bertanza b M.C. Collivignarelli a, A. Abba a
Department of Civil Engineering and Architectural Engineering, University of Pavia, Via Ferrata 1, 27100 Pavia, Italy b Department of Civil, Environmental, Architectural Engineering, and Mathematics, University of Brescia, Via Branze 43, 25123 Brescia, Italy
article info
abstract
Article history:
In the present work we studied the thermophilic biological treatability of high strength
Received 7 March 2014
liquid wastes from a pharmaceutical industry (rich in organic matter e COD: Chemical
Received in revised form
Oxygen Demand, nutrients and salinity). Different mixtures (with concentrations of COD,
23 May 2014
phosphorus and chloride up to 57,000 mg L1, 2000 mg L1 and 9000 mg L1, respectively)
Accepted 16 June 2014
were tested. The pilot plant used in this work was designed and built with dimensions
Available online 24 June 2014
comparable to a semi-industrial unit. The results are therefore representative for full-scale applications. During four months of experimentation, the pilot plant (TAMR e Thermo-
Keywords:
philic Aerobic Membrane Reactor) was operated at 49 ± 1 C and the organic loading rate
Thermophilic Aerobic Membrane
was 1.5e5.5 kgCOD m3 d1 with a hydraulic retention time of 5e10 days.
Reactor (TAMR)
Main results are the following: a) extremely high COD removal rate (up to 98%); b) very
Ultrafiltration
low sludge production (~0.016 kgVSS produced kg1 COD removed); c) suitability as a pre-treatment
Salinity
to a conventional (e.g. activated sludge) biological treatment (the studied pharmaceutical
Sludge minimization
industrial wastewaters are discharged into the sewer system for final polishing in a centralized municipal wastewater treatment plant) and d) high phosphorus removal (up to 99%). © 2014 Elsevier Ltd. All rights reserved.
1.
Introduction
Thermophilic aerobic biological systems work at temperatures higher than 45 C. These conditions can be reached, at reasonable costs, feeding preheated wastewaters with high organic load and providing an adequate thermal insulation of the reactor. Thermophilic processes (TPPs) ensure high removal yields of organic matter (Abeynayaka and
* Corresponding author. ). E-mail address: [email protected] (A. Abba http://dx.doi.org/10.1016/j.watres.2014.06.018 0043-1354/© 2014 Elsevier Ltd. All rights reserved.
Visvanathan, 2011a) and are suited for treatment of wastewaters with high salinity or with the presence of hazardous compounds (Rozich and Colvin, 1997). They can also reduce the content of metals, particularly iron (Slobodkin, 2005). Furthermore, thermophilic treatments show high removal kinetics of biodegradable substrates, about 3e10 times higher than those measured in mesophilic conditions (Lapara and Alleman, 1999). Sludge production is very low compared to mesophilic processes: about 0.05e0.3 kgTSS produced per
191
w a t e r r e s e a r c h 6 3 ( 2 0 1 4 ) 1 9 0 e1 9 8
kgCOD removed (Kurian et al., 2005; Suvilampi and Rintala, 2003). TPPs are able to remove pathogens due to high process temperature (Lapara and Alleman, 1999; Juteau, 2006). Other important advantages of biological thermophilic systems concern heat recovery (Lapara and Alleman, 1999), high removal yields for synthetic molecules (Lapara et al., 2001), flexibility and stability of the process (Lapara and Alleman, 1999; Tripathi and Allen, 1999; Morgan-Sagastume and Allen, 2003). From the other hand, a serious drawback of TPPs consists in the poor sludge settleability (C ¸ etin and Su¨ru¨cu¨, 1990; Barr et al., 1996; Tripathi and Allen, 1999; Lapara and Alleman, 1999). The reason of this is the low ability of thermophilic biomass to form flocs (Lapara and Alleman, 1999): floc forming bacteria hardly grow in a non-ideal environment such as a biological reactor with high temperature. At last, Abeynayaka and Visvanathan (2011a), Kurian and Nakhla (2006) and Kurian et al. (2005) have shown that nitrification in thermophilic treatments does not occur, as a result of low concentration of the nitrifying bacteria (Lapara and Alleman, 1999); only in some cases very slow nitrification rates were observed (Abeynayaka and Visvanathan, 2011b). In order to overcome the disadvantage of the poor sludge sedimentation, a proper solution is the implementation of a Membrane Bioreactor (MBR) system. In particular, using a MBR thermophilic system with pure oxygen, it is possible to operate with higher concentration of biomass (higher than 50 kgTSS m3), resulting in a drastic reduction of the reactor volume and a smaller aeration tank. The undersized aeration tank allows an easy management of the odorous emissions. Based on the new ordinance (regulation) of the European Water Framework Directive (EWFD), in order to achieve the “good quality” for all EU waters (including surface and groundwater) by 2015 (European Commission, 2012), it is important to obtain low concentrations of COD. This represents a challenge due to the presence of the biorefractory fraction, which requires expensive chemical-physical treatments for its transformation and/or removal. It is also
essential the elimination of nutrients (nitrogen and phosphorus). Additionally, since phosphorus is a depleting resource, in the last decade the attention has been focused on the issue of recovery (de-Bashan and Bashan, 2004; Shu et al., 2006; Vaccari and Strigul, 2011). The technology studied in this work, based on a Thermophilic Aerobic Membrane Reactore TAMR, allows an increase of wastewater biodegradability under mesophilic conditions. The downstream polishing in a centralized municipal wastewater treatment plant is therefore more effective in reducing recalcitrant COD. Moreover, phosphorus is precipitated as hydroxyapatite. The experimentation was conducted with a pilot scale (V ¼ 1 m3) TAMR, fed with high strength liquid wastes derived from a pharmaceutical factory. The choice to treat these type of wastewaters with a TPP derived from monitoring for ten years of a full-scale TAMR plant that treats a wide range of liquid wastes, including those from the pharmaceutical industry (Bertanza et al., 2010).
2.
Methods
This experimental research was carried out in a pharmaceutical company that produces an effluent which was treated by a TAMR pilot plant. The company produces chiral materials (high-value amino acids) as starting materials and/or key intermediates for the pharmaceutical and biotech community. It also manufactures materials for the nutraceutical and cosmetic industries and related compounds classified as Active Pharmaceutical Ingredients (APIs).
2.1.
Wastewater characteristics
Four different types of liquid waste were tested (see Table 1). The liquid waste 1 (L.W. 1) has COD concentration of 1,000,000 mg L1 and a total phosphorus (TP) concentration higher than 60,000 mg L1. The liquid waste 2 (L.W. 2) shows
Table 1 e Chemical characteristics of tested liquid wastes. Parameter
pH Electrical conductivity COD NH4 þ N NO2 N NO3 TN TP Chloride Sulphate Toluene Methylene chloride Acetone Ethanol Acetic acid n.m. ¼ not measured.
Liquid wastes e mS cm1 mg L1 mg L1 mg L1 mg L1 mg L1 mg L1 mg L1 mg L1 mg L1 mg L1 mg L1 mg L1 %
L.W. 1
L.W. 2
L.W. 3
L.W. 4
2.45 n.m. 1,000,000
