Wastewater Treatment Plant Site Research Articles

Life cycle assessment of bio-jet fuel from hydrothermal liquefaction of microalgae

Bio-jet fuel is increasingly being produced from feedstocks such as algae and tested in flight. As the industry adopts bio-jet fuels from various feedstocks and conversion processes, life cycle assessment (LCA) is necessary to determine whether these renewable fuels result in lower life cycle greenhouse gas (LC-GHG) emissions than conventional jet fuel. An LCA was performed for a functional unit of 1 GJ of bio-jet fuel produced through thermochemical conversion (hydrothermal liquefaction (HTL)) of microalgae cultivated in wastewater effluent. Two pathways were analyzed to compare the impacts of siting HTL at a wastewater treatment plant (WWTP) to those of siting HTL at a refinery. Base cases for each pathway were developed in part using primary data from algae production in wastewater effluent and HTL experiments of this algae at the University of Kansas. The LC-GHG emissions of these cases were compared to those of conventional jet fuel, and a sensitivity analysis and Monte Carlo analyses were performed. When algal conversion using HTL was modeled at a refinery versus at the WWTP site, the transportation steps of biomass and waste nutrients were major contributors to the LC-GHG emissions of algal bio-jet fuel. The LC-GHG emissions were lower for the algal bio-jet fuel pathway that performs HTL at a WWTP (35.2kg CO2eq/GJ for the base case) than for the pathway for HTL at a refinery (86.5kg CO2eq/GJ for the base case). The LCA results were particularly sensitive to the extent of heat integration, the source of the heat for HTL, and the solids content of dewatered algae. The GHG emissions of algal bio-jet fuel can be reduced by 76% compared to conventional jet fuel with feasible improvements in those sensitive parameters and siting HTL at a WWTP. Therefore, it is critical that transportation logistics, heat integration of biomass conversion processes, and nutrient supply chains be considered as investment and production of bio-jet fuels increase.

Metabolomics forin SituEnvironmental Monitoring of Surface Waters Impacted by Contaminants from Both Point and Nonpoint Sources

We investigated the efficacy of metabolomics for field-monitoring of fish exposed to wastewater treatment plant (WWTP) effluents and nonpoint sources of chemical contamination. Lab-reared male fathead minnows (Pimephales promelas, FHM) were held in mobile monitoring units and exposed on-location to surface waters upstream and downstream of the effluent point source, as well as to the actual effluent at three different WWTP sites in Minnesota. After four days of exposure, livers were collected, extracted, and analyzed by (1)H NMR spectroscopy and GC-MS to characterize responses of the hepatic metabolome. Multivariate statistical analysis revealed distinct metabolite profile changes in response to effluent exposure from each of the three WWTPs. Differences among locations (i.e., upstream, downstream, and effluent) within each of the three sites were also identified. These observed differences comport with land-use and WWTP characteristics at the study sites. For example, at one of the sites, the metabolomic analyses suggested a positive interactive response from exposure to WWTP effluent and nearby nonpoint (likely agricultural related) contamination. These findings demonstrate the utility of metabolomics as a field-based technique for monitoring the exposure of fish to impacted surface waters.

Determination of selected acidic pharmaceuticals and caffeine in Ergene basin, in Turkey

<p>In this study, surface and wastewater in Çorlu, Tekirdağ has been monitored for ibuprofen, naproxen and diclofenac as non-steroidal anti-inflammatory drugs (NSAIDs), salicylic acid as an analgesic and caffeine. For this goal, samples were collected from 5 areas during winter and summer times (W1, W2, W3, W4 and W5) working in the field of a wastewater treatment plant site, only Çerkezköy industrial district W4. Different solid-phase extractions, pH and derivatization conditions were tested with some anti-inflammatory drugs and caffeine of Gas-Chromatography-Mass Spectrometry in environment samples and their identification and quantification at trace levels were made (ng L-1). Diclofenac (LOQ = 4.3 ng L-1) and ibuprofen (LOQ = 134.1 ng L-1) could not be determined. Other concentration levels of arranged drugs range between 2.12 -13.58 ng L-1 naproxen, 15.74-18.74 ng L-1 salicylic acid and 5.8-121.2 ng L-1 caffeine.</p>

Wastewater Treatment Plant and Landfills as Sources of Polyfluoroalkyl Compounds to the Atmosphere

Polyfluoroalkyl compounds (PFCs) were determined in air around a wastewater treatment plant (WWTP) and two landfill sites using sorbent-impregnated polyurethane foam (SIP) disk passive air samplers in summer 2009. The samples were analyzed for five PFC classes (i.e., fluorotelomer alcohols (FTOHs), perfluorooctane sulfonamides (FOSAs), sulfonamidoethanols (FOSEs), perfluoroalkyl sulfonic acids (PFSAs), and perfluoroalkyl carboxylic acids (PFCAs)) to investigate their concentration in air, composition and emissions to the atmosphere. ∑PFC concentrations in air were 3-15 times higher within the WWTP (2280-24 040 pg/m(3)) and 5-30 times higher at the landfill sites (2780-26 430 pg/m(3)) compared to the reference sites (597-1600 pg/m3). Variations in the PFC pattern were observed between the WWTP and landfill sites and even within the WWTP site. For example, FTOHs were the predominant PFC class in air for all WWTP and landfill sites, with 6:2 FTOH as the dominant compound at the WWTP (895-12 290 pg/m(3)) and 8:2 FTOH dominating at the landfill sites (1290-17 380 pg/m(3)). Furthermore, perfluorooctane sulfonic acid (PFOS) was dominant within the WWTP (43-171 pg/m(3)), followed by perfluorobutanoic acid (PFBA) (55-116 pg/m(3)), while PFBA was dominant at the landfill sites (101-102 pg/m(3)). It is also noteworthy that the PFCA concentrations decreased with increasing chain length and that the emissions for the even chain length PFCAs outweighed emissions for the odd chain length compounds. Furthermore, highly elevated PFC concentrations were found near the aeration tanks compared to the other tanks (i.e., primary and secondary clarifier) and likely associated with increased volatilization during aeration that may be further enhanced through aqueous aerosol-mediated transport. ∑PFC yearly emissions estimated using a simplified dispersion model were 2560 g/year for the WWTP, 99 g/year for landfill site 1, and 1000 g/year for landfill site 2. These results highlight the important role of WWTPs and landfills as emission sources of PFCs to the atmosphere.

Evolution of polycyclic aromatic hydrocarbons (PAHs) and heavy metals in sludge samples from conventional activated sludge wastewater treatment plants

AbstractThis paper presents results on the presence and evolution of PAHs and heavy metals in a conventional activated sludge wastewater treatment plant (WWTP). The 16 PAHs recommended by the EPA were determined. On the other hand, 13 heavy metals were studied (Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Ti and Zn). Moreover, water content, organic and mineral matter were determined for the generic characterization of the sludges in an attempt to assess their agricultural value. The sewage sludges originated from the Guadalete WWTP site in Jerez de la Frontera (Cádiz, Spain). PAHs have been extracted by microwave energy. High performance liquid chromatography coupled with diode array and fluorescence detectors have been used (HPLC‐DAD‐FL). Heavy metals were analyzed by ICP‐AES. The results showed that total PAHs concentration (sum of 16 EPA PAHs) varied between 6757 ng g−1 dry matter (DM) for compost and 4176 ng g−1 DM for secondary sludge. The most abundant PAH is pyrene. The highest concentration of heavy metals was also found in compost (51750 mg kg−1 DM) and lowest concentration in secondary sludge (24250 mg kg−1). In order to obtain global conclusions from all results, several chemometrical techniques of pattern recognition were applied. Copyright © 2008 John Wiley & Sons, Ltd.

Response of Estuarine Biofilm Microbial Community Development to Changes in Dissolved Oxygen and Nutrient Concentrations

The information content and responsiveness of microbial biofilm community structure, as an integrative indicator of water quality, was assessed against short-term changes in oxygen and nutrient loading in an open-water estuarine setting. Biofilms were grown for 7-day periods on artificial substrates in the Pensacola Bay estuary, Florida, in the vicinity of a wastewater treatment plant (WWTP) outfall and a nearby reference site. Substrates were deployed floating at the surface and near the benthos in 5.4 m of water. Three sampling events covered a 1-month period coincident with declining seasonal WWTP flow and increasing dissolved oxygen (DO) levels in the bottom waters. Biomass accumulation in benthic biofilms appeared to be controlled by oxygen rather than nutrients. The overriding effect of DO was also seen in DNA fingerprints of community structure by terminal restriction fragment length polymorphism (T-RFLP) of amplified 16S rRNA genes. Ribotype diversity in benthic biofilms at both sites dramatically increased during the transition from hypoxic to normoxic. Terminal restriction fragment length polymorphism patterns showed pronounced differences between benthic and surface biofilm communities from the same site in terms of signal type, strength, and diversity, but minor differences between sites. Sequencing of 16S rRNA gene clone libraries from benthic biofilms at the WWTP site suggested that low DO levels favored sulfate-reducing prokaryotes (SRP), which decreased with rising oxygen levels and increasing overall diversity. A 91-bp ribotype in the CfoI-restricted 16S rRNA gene T-RFLP profiles, indicative of SRP, tracked the decrease in relative SRP abundance over time.

Examination of reproductive endpoints in goldfish (Carassius auratus) exposed in situ to municipal sewage treatment plant effluent discharges in Michigan, USA.

Effects of representative mid-Michigan (USA) wastewater treatment plant (WWTP) effluents on the reproductive physiology of common goldfish (Carassius auratus) were assessed in situ by measuring plasma concentrations of vitellogenin (VTG), 17 beta-estradiol (E2), and testosterone (T), and evaluating gonad histology. Caged adult male and female goldfish were exposed for six weeks to WWTP effluents. One riverine site and one lacustrine site were included as references for comparison to WWTP sites. There was differential growth and gonadal development among locations, which confounded the interpretation of biomarker responses. A linear contrast model was developed by analysis of covariance, and adjusted values were developed for concentrations of VTG, E2, and T in the plasma of both male and female fish. In general, VTG concentrations were significantly less in male than in female goldfish. Most concentrations of VTG in male goldfish were less than the method detection limit. There were no significant differences in plasma VTG of either male or female goldfish among locations or between sites at WWTPs and reference sites. Concentrations of E2 in the plasma of female goldfish were similar among WWTP sites, all of which were less than in females at a pond reference location. Concentrations of E2 in the plasma of male goldfish were similar at all WWTP locations, except for one, where they were greater. No consistent trends in hormone concentrations or gonadal histology could be attributed to putative endocrine disrupter exposure in WWTP effluents. The results indicate that the risk for estrogen agonist exposure below these mid-Michigan WWTPs is small.

Purification of rotating biological contactor (RBC) treated domestic wastewater for reuse in irrigation by biofilm channel

Abstract Total nitrogen (TN-N) below 10 mg l −1 was suggested for short-term irrigation application in Taiwan. TN-N in the treated effluent of a Rotating Biological Contactor (RBC) system was about 18 mg l −1 and further reclamation was required for reuse purpose. A channel with nine sections, 6 m long, 30 cm in width and 20 cm in height, with plastic sheets as a biofilm carrier inserted inside, was set up at a wastewater treatment plant site to test the purification efficiency. Six different flow velocities were tested in this research. The nitrogen conversion rate increased with velocity until an optimal velocity of 1 cm s −1 was reached. The kinetic constants of Total Kjeldahl nitrogen (TKN) and TN-N were found to be 4.57 and 7.51 (mg l −1 h −1 ). The unit area biofilm carrier removal rates for TKN and TN-N were found to be 1.34 and 2.20 (g m −2 d −1 ) and the unit volume removal rates for TKN and TN-N were 140.72 and 231.18 (g m −3 d −1 ), respectively, at this optimal velocity. The TKN and TN-N concentrations kinetic rates fit a zero-order approach. The TN-N concentration criterion of 10 mg l −1 was found to be possible with this biofilm channel.

Effects of exposure to municipal wastewater in situ on the reproductive physiology of the fathead minnow (Pimephales promelas)

AbstractEffects of representative central Michigan wastewater treatment plant (WWTP) effluents on the reproductive physiology of fathead minnows (Pimephales promelas) were assessed in situ by measuring plasma concentrations of vitellogenin (VTG), 17β‐estradiol (E2), and testosterone (T), and evaluating gonad histology and male secondary sex characteristics. Caged adult male and female fathead minnows were exposed for 3 weeks to WWTP effluent. One riverine site and one lacustrine site were included as references for comparison to WWTP sites. Plasma concentrations of VTG, E2, and T in female fish, quantified by enzyme‐linked immunosorbent assay (ELISA), were greater at the lacustrine site than the riverine site or WWTP sites. None of the male fish had mean plasma VTG concentrations similar to that observed in females. Most VTG concentrations in male fish were less than the VTG ELISA detection limit. Female plasma concentrations of E2 were similar among riverine and WWTP sites. Plasma concentrations of E2 in male fish were greater than the riverine site at all WWTP sites except the Williamston site, but were not significantly different from the lacustrine site. Concentrations of T in female and male fish were similar among riverine and exposure sites. No trends in hormone concentrations, male secondary sex characteristics, or gonad histology could be attributed to putative endocrine disrupter exposure in WWTP effluent. The results indicate that the risk for estrogen agonist exposure below these central Michigan WWTPs is small.

Chromatographic determination of aliphatic hydrocarbons and polyaromatic hydrocarbons (PAHs) in a sewage sludge

A simple chromatographic method, proposed by Aceves et al. (1988), for the determination of aliphatic hydrocarbons and polyaromatic hydrocarbons (PAHs) was used. The results from a study of the presence and temporal variability of the aliphatic hydrocarbons and polyaromatic hydrocarbons (PAHs) in sewage sludge are shown in this work. The sewage sludges originated from the Arazuri waste water treatment plant site in Pamplona (Spain). The organic pollutants have been extracted from the sewage sludge by a Soxhlet apparatus. Aliphatic hydrocarbons and PAHs are separated from the rest of the pollutants on a chromatographic column. Flame ionization (FID) and mass spectroscopy (MS) detectors have been used. The results showed that aliphatic hydrocarbons concentration varied between 230 and 1420 mg kg −1 dry matter (DM). The PAHs appeared in smaller quantitie of between 128 and 482 mg kg −1 (DM). The factor analysis of the results allowed us to verify the different origin of the aliphatic hydrocarbons and the PAHs.