Thomas Wintgens

Endocrine disrupter removal from wastewater using membrane bioreactor and nanofiltration technology

Endocrine disrupting compounds can affect hormone systems in organisms. However, conventional wastewater treatment plants are not able to remove these substances sufficiently before disposing effluent into the environment. Membrane technology, which is proving to be an effective barrier to these substances, is the subject of this research. The removal techniques under investigation are membrane bioreactors and nanofiltration. Initial results using wastewater from a dumpsite leachate plant indicate removal of more than 90% of nonylphenol (NP) and bisphenol (BPA). The mass balance indicates the membrane bioreactor is the most important process step in removal while the granulated activated carbon treatment, applied downstream, is a further polishing stage. Eleven different nanofiltration membranes were tested in the laboratory set-up. The observed retentions for NP and BPA ranged between 70% and 100%. The contact angle is an indicator for the hydrophobicity of a membrane, whose influence on the permeability and retention of NP was evident. Regarding the retention of BPA no dependency on the contact angle was observed.

Quantitative PCR Monitoring of Antibiotic Resistance Genes and Bacterial Pathogens in Three European Artificial Groundwater Recharge Systems

ABSTRACT Aquifer recharge presents advantages for integrated water management in the anthropic cycle, namely, advanced treatment of reclaimed water and additional dilution of pollutants due to mixing with natural groundwater. Nevertheless, this practice represents a health and environmental hazard because of the presence of pathogenic microorganisms and chemical contaminants. To assess the quality of water extracted from recharged aquifers, the groundwater recharge systems in Torreele, Belgium, Sabadell, Spain, and Nardò, Italy, were investigated for fecal-contamination indicators, bacterial pathogens, and antibiotic resistance genes over the period of 1 year. Real-time quantitative PCR assays for Helicobacter pylori, Yersinia enterocolitica, and Mycobacterium avium subsp. paratuberculosis, human pathogens with long-time survival capacity in water, and for the resistance genes ermB, mecA, blaSHV-5, ampC, tetO, and vanA were adapted or developed for water samples differing in pollutant content. The resistance genes and pathogen concentrations were determined at five or six sampling points for each recharge system. In drinking and irrigation water, none of the pathogens were detected. tetO and ermB were found frequently in reclaimed water from Sabadell and Nardò. mecA was detected only once in reclaimed water from Sabadell. The three aquifer recharge systems demonstrated different capacities for removal of fecal contaminators and antibiotic resistance genes. Ultrafiltration and reverse osmosis in the Torreele plant proved to be very efficient barriers for the elimination of both contaminant types, whereas aquifer passage followed by UV treatment and chlorination at Sabadell and the fractured and permeable aquifer at Nardò posed only partial barriers for bacterial contaminants.

Emerging contaminants and treatment options in water recycling for indirect potable use

Solutions to global water stress problems are urgently needed yet must be sustainable, economical and safe. The utilisation of alternative water sources like reclaimed municipal wastewater is one of the most obvious and promising options in integrated water resources management. Among the various beneficial uses of reclaimed wastewater Aquifer Recharge (AR) receives growing attention because it features advantages such as additional natural treatment, storage capacity to buffer seasonal variations of supply and demand as well as mixing with natural water bodies which promotes the acceptance of further uses, particularly indirect potable use. Major concerns about the safety of this exploitation route of an alternative water source are connected to microbial and chemical contaminants occurring in wastewater, among which are emerging trace organics like endocrine disrupters and pharmaceuticals. This paper reviews the current international debate about the relevance of emerging contaminants and technical mitigation options in water recycling for indirect potable use.

Quantification of pathogenic microorganisms and microbial indicators in three wastewater reclamation and managed aquifer recharge facilities in Europe

Managed Aquifer Recharge (MAR) is becoming an attractive option for water storage in water reuse processes as it provides an additional treatment barrier to improve recharged water quality and buffers seasonal variations of water supply and demand. To achieve a better understanding about the level of pathogenic microorganisms and their relation with microbial indicators in these systems, five waterborne pathogens and four microbial indicators were monitored over one year in three European MAR sites operated with reclaimed wastewater. Giardia and Cryptosporidium (oo)cysts were found in 63.2 and 36.7% of the samples respectively. Salmonella spp. and helminth eggs were more rarely detected (16.3% and 12.5% of the samples respectively) and Campylobacter cells were only found in 2% of samples. At the Belgian site advanced tertiary treatment technology prior to soil aquifer treatment (SAT) produced effluent of drinking water quality, with no presence of the analysed pathogens. At the Spanish and Italian sites amelioration of microbiological water quality was observed between the MAR injectant and the recovered water. In particular Giardia levels decreased from 0.24-6.14 cysts/L to 0-0.01 cysts/L and from 0.4-6.2 cysts/L to 0-0.07 cysts/L in the Spanish and Italian sites respectively. Salmonella gene copies and Giardia cysts were however found in the water for final use and/or the recovered groundwater water at the two sites. Significant positive Spearman correlations (p<0.05, r(s) range: 0.45-0.95) were obtained, in all the three sites, between Giardia cysts and the most resistant microbial markers, Clostridium spores and bacteriophages.

Sorption behavior of potential organic wastewater indicators with soils.

Soil-aquifer treatment is a wastewater treatment and reclamation option to facilitate beneficial water reuse. The fate of wastewater originated micropollutants in the soil-aquifer system is important to understand. In the study the sorption behavior of potential wastewater indicators such as two antiepileptic drugs (carbamazepine, primidone), one sulfonamide (sulfamethoxazole), and one corrosion inhibitor (benzotriazole) were determined with three natural soils (Lufa 2.2, Euro Soil 5, and Wulpen sand) that differed in pH, organic carbon content and particle size distribution. As aqueous phase a 0.01M CaCl(2) solution as well as the effluent of a municipal wastewater treatment plant was used. Affinities of all analytes to the soil increased from Wulpen sand, over Lufa 2.2 to Euro Soil 5, indicating that the organic carbon contents might be crucial for sorption. Isotherms were well described by the Freundlich model. Sorption was mainly close to linear (n=0.93-1.07) for most target compounds and soils. Desorption gave rise to a small hysteresis only for Euro Soil 5 which was likely artificial, due to slow desorption kinetics beyond 24h used in the experiment. All sorption studies confirmed that Carbamazepine, Benzotriazole and Primidone are appropriate to be used as wastewater indicator substances based on their low sorption affinity to soils, while the suitability of Sulfamethoxazole is limited due to the formation of non-extractable residues, especially at lower pH values.

Valuing the subsurface pathogen treatment barrier in water recycling via aquifers for drinking supplies

A quantitative microbial risk assessment (QMRA) was performed at four managed aquifer recharge (MAR) sites (Australia, South Africa, Belgium, Mexico) where reclaimed wastewater and stormwater is recycled via aquifers for drinking water supplies, using the same risk-based approach that is used for public water supplies. For each of the sites, the aquifer treatment barrier was assessed for its log(10) removal capacity much like for other water treatment technologies. This information was then integrated into a broader risk assessment to determine the human health burden from the four MAR sites. For the Australian and South African cases, managing the aquifer treatment barrier was found to be critical for the schemes to have low risk. For the Belgian case study, the large treatment trains both in terms of pre- and post-aquifer recharge ensures that the risk is always low. In the Mexico case study, the risk was high due to the lack of pre-treatment and the low residence times of the recharge water in the aquifer. A further sensitivity analysis demonstrated that human health risk can be managed if aquifers are integrated into a treatment train to attenuate pathogens. However, reduction in human health disease burden (as measured in disability adjusted life years, DALYs) varied depending upon the number of pathogens in the recharge source water. The beta-Poisson dose response curve used for translating rotavirus and Cryptosporidium numbers into DALYs coupled with their slow environmental decay rates means poor quality injectant leads to aquifers having reduced value to reduce DALYs. For these systems, like the Mexican case study, longer residence times are required to meet their DALYs guideline for drinking water. Nevertheless the results showed that the risks from pathogens can still be reduced and recharging via an aquifer is safer than discharging directly into surface water bodies.

Advanced enzymatic elimination of phenolic contaminants in wastewater: a nano approach at field scale

The removal of recalcitrant chemicals in wastewater treatment systems is an increasingly relevant issue in industrialized countries. The elimination of persistent xenobiotics such as endocrine-disrupting chemicals (EDCs) emitted by municipal and industrial sewage treatment plants remains an unsolved challenge. The existing efficacious physico-chemical methods, such as advanced oxidation processes, are resource-intensive technologies. In this work, we investigated the possibility to remove phenolic EDCs [i.e., bisphenol A (BPA)] by means of a less energy and chemical consuming technology. To that end, cheap and resistant oxidative enzymes, i.e., laccases, were immobilized onto silica nanoparticles. The resulting nanobiocatalyst produced at kilogram scale was demonstrated to possess a broad substrate spectrum regarding the degradation of recalcitrant pollutants. This nanobiocatalyst was applied in a membrane reactor at technical scale for tertiary wastewater treatment. The system efficiently removed BPA and the results of long-term field tests illustrated the potential of fumed silica nanoparticles/laccase composites for advanced biological wastewater treatment.

Performance of an anaerobic membrane bioreactor for pharmaceutical wastewater treatment

Anaerobic treatment of wastewater and waste organic solvents originating from the pharmaceutical and chemical industries was tested in a pilot anaerobic membrane bioreactor, which was operated for 580days under different operational conditions. The goal was to test the long-term treatment efficiency and identify inhibitory factors. The highest COD removal of up to 97% was observed when the influent concentration was increased by the addition of methanol (up to 25gL-1 as COD). Varying and generally lower COD removal efficiency (around 78%) was observed when the anaerobic membrane bioreactor was operated with incoming pharmaceutical wastewater as sole carbon source. The addition of waste organic solvents (>2.5gL-1 as COD) to the influent led to low COD removal efficiency or even to the breakdown of anaerobic digestion. Changes in the anaerobic population (e.g., proliferation of the genus Methanosarcina) resulting from the composition of influent were observed.

Nitrification performance in a membrane bioreactor treating industrial wastewater.

The influence of industrial (pharmaceutical and chemical) wastewater composition on membrane bioreactor (MBR) performance was investigated in a pilot-scale installation. The study focussed on nitrification performance, which was evaluated based on influent and effluent parameters as well as batch nitrification rate tests. The industrial wastewater was pumped into the MBR in a mixture with municipal wastewater at constant flow rate. The loading of the MBR with industrial wastewater was increased stepwise from 0 to 75% share in the mixed influent to study the adaptation of nitrifying bacteria. Stable nitrification performance was observed until the content of industrial wastewater in the influent reached 40%, with effluent values of around 0.56 mg L(-1) NH4-N and 98.3% ammonia removal. Breakdown of nitratation was observed at a 40% industrial wastewater dose and breakdown of nitritation at a 50% dose, respectively. However, after several months of adaptation, both processes recovered. No nitrification was observed when the industrial wastewater share exceeded 50%. Adaptation of nitrifying bacteria in the MBR was also confirmed by results of kinetic tests. The inhibition effect of the concentrated industrial wastewater to the MBR sludge decreased substantially after several months of exposure, while the inhibition of referential activated sludge remained constant.

Removal of endocrine disruptors and cytostatics from effluent by nanofiltration in combination with adsorption on powdered activated carbon

Direct capillary nanofiltration also in combination with an upstream powdered activated carbon treatment was tested for high quality water reuse of tertiary effluent from a municipal wastewater treatment plant. Two endocrine disruptors (BPA and EE2) and two cytostatics (CytR and 5-FU) were spiked in concentrations of 1 to 2 microg/L to evaluate the process performance. In direct NF the real total removal of the micropollutants was between 5 and 40%. Adsorption to the membrane played a major role leading to a seemingly total removal between 35 and 70%. Addition of powdered activated carbon and lignite coke dust largely reduced the influence from adsorption to the membrane and increased the total removal to >95 to 99.9% depending on the PAC type and dose. The cytostatics showed already in direct NF a very high removal due to unspecified losses. Further investigations are ongoing to understand the underlying mechanism. The PAC/NF process provided a consistently high permeate quality with respect to bulk and trace organics.