Removal of micropollutants and recovery of nutrients in anaerobic wastewater treatment
This research is being performed under the thrust of the NEW (nutrients, energy, clean water) paradigm where wastewater treatment plants are seen as opportunities for nutrient and resource recovery. As energy demands continue to rise, wastewater treatment must be performed in more efficient manners. Moreover, it is imperative to recovery nutrients while removing harmful micropollutants from the water environment. This research project is focused on developing innovative applications for recovering nutrients and removing micropollutants from domestive wastewater that was treated anaerobically (see more on Dr. Zitomer and his anaerobic membrane work).This research combines ion exchange to remove and recover nutrients as well as biochar sorption to capture micropollutants.This process allows for production of struvite as a soil conditioner. This work aims to understand the relationship between nutrient and micropollutant removal in relation to ion exchange on biochar properties.
This work is in collaboration with Prof. Brooke Mayer (Civil Engineering).
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Antimicrobial resistance genes
Antibiotic resistance is an increasingly serious public health problem. Antibiotic resistance in bacteria has been known to arise from exposure to antibiotics, but recent literature has shown that antimicrobials used for personal hygiene and sanitation may also have an active role in the proliferation ofresistance to clinically important antibiotics. Given that antimicrobials accumulate in wastewater treatment, antimicrobials in these systems could potentially have a significant impact in antibiotic resistance in the environment. Triclosan and triclocarban are two antimicrobials which are ubiquitously found in wastewater treatment and persist in sub-therapeutic concentrations. Little research has been performed to show how loading rates of these compounds in anaerobic digestion affect the proliferation of antimicrobial resistance. With mounting pressure to remove these compounds from the consumer market, further research is needed to understand how wastewater treatment systems may react if these compounds are no longer present. The goal of this research is to elucidate how adaptation time to triclosan and triclocarban impacts the abundance of antimicrobial resistance genes in anaerobic digestion.
This work is in collaboration with Prof. Dan Zitomer (Civil Engineering) and Prof. Krassi Hristova (Biological Sciences).
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Removal of estrogenic micropollutants from wastewater biosolids via pyrolysis
Handling of wastewater biosolids is an expensive undertaking for wastewater treatment plants (WWTPs). Land applying biosolids, however, can alleviate financial burdens as biosolids can be sold as a valuable soil conditioner. Public concern over land application hampers the value of biosolids, and concern stems from micropollutants associated with biosolids. Micropollutants encompass a broad range of organic chemicals, including antimicrobials, detergents, and estrogenic compounds which can lead to such effects as feminization of fish. Wastewater treatment processes are not specifically designed to remove micropollutants and thus many micropollutants remain in the biosolids. The biosolids-soil amendment provides a pathway for these micropollutants into the environment. Currently measures are not sufficient for removing micropollutants from biosolids. This research will focus on pyrolysis, the partial decomposition of organic material in an oxygen-deprived system under high temperatures, as a sustainable solution for removing estrogenic compounds from these solids while producing a useable soil conditioner in biochar. Pyrolysis has the possibility to have minimal or no net energy loss after the production of the syngas and oil. It is hypothesized that pyrolysis will reduce the estrogenic load of biosolids by volatilizing or transforming estrogenic compounds. At the conclusion of this research we will better understand if pyrolysis can be a sustainable option to remove estrogenic compounds while producing a beneficial soil-amendment product. This work combines lab-scale studies with sampling at full-scale plants to determine the benefit of adding pyrolysis as a polishing treatment step. This work is graciously funded by the Lafferty Foundation and the Marquette Graduate school SFF/RRG program.
The portion of this work funded by the Lafferty Foundation is in collaboration with Prof. Dan Zitomer (Civil Engineering)
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The fate of micropollutants following pyrolysis
The spread of micropollutants (e.g. prescription drugs, plasticizers, and pesticides) into the environment is receiving considerable attention as micropollutants are regularly detected in water reclamation facility effluents and residual solids, or biosolids. Concern exists over these micropollutants due to their demonstrated ability to harm or alter aquatic life and spread antibiotic resistance. Pyrolysis the thermochemical decomposition of organic matter in an oxygen free environment in an elevated temperature range (400 – 850 °C)—offers potential for micropollutant removal from biosolids while producing renewable energy and a value-added solid product called biochar. The goal of this research is to evaluate pyrolysis of wastewater biosolids for its ability to remove and/or destroy micropollutants found in biosolids. Specifically, the fate of micropollutants following pyrolysis will be determined in the solid, liquid, or gas phase to determine if micropollutants are destroyed. This work is funded by NSF-IUCRC and is done in collaboration with Prof. Dan Zitomer (Civil Engineering).
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The effect of co-digestion on the anaerobic degradation of NPEO to NP
Nonylphenol (NP) and nonylphenol ethoxylates (NPEO) represent one of the most prevalent groups of estrogenic compounds in wastewater. These compounds are used in detergents, and NPEO biodegrade to NP during wastewater treatment. As a result of the hydrophobic nature of nonylphenol mono and diethoxylates (NP1EO, NP2EO), these compounds readily sorb to biosolids where they are often stabilized through anaerobic digestion. NPEO readily degrade to NP under anaerobic conditions while NP does not readily degrade. The extent of this biodegradation process in wastewater treatment is important because NP is more estrogenic than NPEO. This biodegradation process is typically limited by either bioavailability or metabolism. This research investigates the role that co-digestion, relative to conventional anaerobic digestion, has on the overall metabolic activity of the microbial community and the biodegradation of NPEO to NP.
This work is done in collaboration with Prof. Dan Zitomer (Civil Engineering), an expert on co-digestion.
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