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wastewater treatment

Ben L Gilby, Andrew D Olds, Rod M Connolly, Tim Stevens, Christopher J Henderson, Paul S Maxwell, Ian R Tibbetts, David S Schoeman, David Rissik, Thomas A Schlacher
Management authorities seldom have the capacity to comprehensively address the full suite of anthropogenic stressors, particularly in the coastal zone where numerous threats can act simultaneously to impact reefs and other ecosystems. This situation requires tools to prioritise management interventions that result in optimum ecological outcomes under a set of constraints. Here we develop one such tool, introducing a Bayesian Belief Network to model the ecological condition of inshore coral reefs in Moreton Bay (Australia) under a range of management actions...
2016: PloS One
F Stenström, J la Cour Jansen
Bioaugmentation of nitrifiers from a side-stream treatment is an efficient method for boosting the mainstream process at a wastewater treatment plant (WWTP). Although this technology has been known for several years, the number of full-scale applications for it is limited. For a WWTP approaching its critical nitrogen load capacity, the benefits are doubled if the introduced side-stream treatment for digester supernatant is combined with bioaugmentation. Not only is the nitrogen load to the mainstream process decreased by 10-25%, but the mainstream process is also boosted with nitrifiers, increasing the nitrifying capacity...
October 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Antoine Prandota Trzcinski, Lily Ganda, Chinagarn Kunacheva, Dong Qing Zhang, Li Leonard Lin, Guihe Tao, Yingjie Lee, Wun Jern Ng
In light of global warming mitigation efforts, increasing sludge disposal costs, and need for reduction in the carbon footprint of wastewater treatment plants, innovation in treatment technology has been tailored towards energy self-sufficiency. The AB process is a promising technology for achieving maximal energy recovery from wastewaters with minimum energy expenditure and therefore inherently reducing excess sludge production. Characterization of this novel sludge and its comparison with the more conventional B-stage sludge are necessary for a deeper understanding of AB treatment process design...
October 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Tiele Caprioli Machado, Marla Azário Lansarin
The hexavalent chromium, Cr(VI), which is generated in the electroplating process, is toxic to most organisms and potentially harmful to human health. The method generally used for remediation of wastewater containing Cr(VI) employs chemicals with high toxicity. This work proposes an alternative technology for the treatment of these wastewaters, based on photochemical reduction of Cr(VI) by alcohols under radiation, which is environmentally sustainable and economically viable. Initially, a batch reactor in laboratory scale was used to determine the best experimental conditions and its specific reaction rate was calculated...
October 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Sahar Soltan, Hoda Jafari, Shahrara Afshar, Omid Zabihi
In the present study, silicon dioxide (SiO2) nanoparticles were loaded to titanium dioxide (TiO2) nano-particles by sol-gel method to make a high porosity photocatalyst nano-hybrid. These photocatalysts were synthesized using titanium tetrachloride and tetraethyl orthosilicate as titanium and silicon sources, respectively, and characterized by X-ray powder diffraction (XRD) and scanning electron microscope methods. Subsequently, the optimizations of the component and operation conditions were investigated. Then, nano-sized TiO2 and TiO2-SiO2 were supported on concrete bricks by the dip coating process...
October 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Cuizhen Sun, Jinwei Qiu, Zhibin Zhang, Taha F Marhaba, Yanhao Zhang
In this paper, flocculating performance and mechanisms of a new composite coagulant, poly-ferric aluminum chloride-polydimethyl diallylammonium chloride (PFAC-PD) with different OH(-)/(Fe(3+) + Al(3+)) molar ratios, were investigated for humic acid (HA)-kaolin synthetic wastewater treatment. The impact of OH(-)/(Fe(3+) + Al(3+)) molar ratios on the removal efficiencies of turbidity and dissolved organic carbon, specific UV absorbance, coagulation mechanisms and dynamics was explored during the coagulation process using composite coagulants...
October 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Dilawar Farhan Shams, Alexandre Rubio, Panagiotis Elefsiniotis, Naresh Singhal
Nitrate concentration in the final effluent is a key issue in pre-denitrification biological treatment systems. This study investigated post-denitrification with alginate beads containing immobilized activated sludge microorganisms and organic carbon source. A batch study was first performed to identify suitable carbon sources among acetate, glucose, calcium tartrate, starch and canola oil on the basis of nitrate removal and bead stability. Canola oil and starch beads exhibited significantly higher denitrification rates, greater bead stability and lower nitrite accumulation (6 mg/L and 10 mg/L, respectively)...
October 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Michal Sposob, Carlos Dinamarca, Rune Bakke
Sulphides are present in many wastewater streams; their removal is important due to corrosiveness, toxicity and unpleasant odour, and can be carried out by anaerobic biological treatment. This study focuses on the temperature effect (25-10 °C) on an expanded granular sludge bed (EGSB) reactor for sulphide removal using nitrate as electron acceptor. The reactor was run at a NO3(-)/HS(-) molar ratio of 0.35 and pH of 8.5-9.0. Samples were analysed by ion chromatography (NO3(-), SO4(2-) and S2O3(2-)), spectrophotometry (S(2-)) and by scanning electron microscopy (SEM)...
October 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Long Pang, Peijie Yang, Jihong Zhao, Hongzhong Zhang
Organophosphate esters (OPs), widely used as flame retardants and plasticizers, are regarded as a class of emerging pollutants. The effluent of municipal wastewater treatment plants is generally considered to be the main contributor of OP pollution to the surface water. In this study, anoxic-oxic (AO) and University of Capetown (UCT) processes were selected to investigate the removal efficiency of OPs. The results indicated that the UCT process showed better removal efficiency than that of the AO process. For the chlorinated OPs, approximately 12...
October 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Suymara Toledo Miranda, Antonio Teixeira de Matos, Gheila Corrêa Ferres Baptestini, Alisson Carraro Borges
In horizontal subsurface flow constructed wetlands (HSSF-CWs), the main operational problem is clogging of the porous medium. In this study, the unclogging of HSSF-CWs was evaluated, at rest, by adding a nitrogen-based nutrient solution to the influent. For this, six HSSF-CWs were used, consisting of two uncultivated (CW-C), two cultivated with Tifton 85-grass (Cynodon spp.) (CW-T) and two cultivated with alligator weed (Alternanthera philoxeroides) (CW-A), which were fully clogged after being used for the treatment of swine wastewater...
October 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Y Amerlinck, W De Keyser, G Urchegui, I Nopens
At wastewater treatment plants (WWTPs) aeration is the largest energy consumer. This high energy consumption requires an accurate assessment in view of plant optimization. Despite the ever increasing detail in process models, models for energy production still lack detail to enable a global optimization of WWTPs. A new dynamic model for a more accurate prediction of aeration energy costs in activated sludge systems, equipped with submerged air distributing diffusers (producing coarse or fine bubbles) connected via piping to blowers, has been developed and demonstrated...
October 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Kun Zhong, Yi-Yong Luo, Zheng-Song Wu, Qiang He, Xue-Bin Hu, Qi-Wu Jie, Yan-Ting Li, Shao-Jie Wang
A vertical flow constructed wetland was combined with a biological aerated filter to develop an ecological filter, and to obtain the optimal operating parameters: The hydraulic loading was 1.55 m(3)/(m(2)·d), carbon-nitrogen ratio was 10, and gas-water ratio was 6. The experimental results demonstrated considerable removal efficiency of chemical oxygen demand (COD), ammonia nitrogen (NH4(+)-N), total nitrogen (TN), and total phosphorus (TP) in wastewater by the ecological filter, with average removal rates of 83...
October 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Charles Humphrey, Brent Serozi, Guy Iverson, Jordan Jernigan, Sushama Pradhan, Michael O'Driscoll, Eban Bean
The goal of this study was to gain a better understanding of the PO4-P treatment efficiency of onsite wastewater systems (OWS) installed in nutrient-sensitive watersheds of the North Carolina Piedmont. Four OWS including two conventional and two single-pass sand filter (SF) systems were evaluated at sites with clay-rich soils. Piezometers were installed near all of the OWS, and down-gradient from the conventional OWS for groundwater collection and characterization. Septic tanks, groundwater, SF effluent, and surface waters were sampled each season during 2015 (five times) and analyzed for PO4-P and Cl concentrations and for various environmental parameters...
October 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Salar Haghighatafshar, Britt-Marie Wilén, Andreas Thunberg, Marinette Hagman, Annika Nyberg, Jonas Grundestam, Maria Mases, Jes la Cour Jansen
Vacuum degassing of activated sludge was tested at eight different Swedish wastewater treatment plants with laboratory-scale equipment in batch mode in order to evaluate its efficiency on improvement of sludge compaction and settling properties. The results show that the efficiency of the degassing technique is mainly dependent on the initial sludge volume index (SVI) of the target sludge which was found to be related to its process configuration. Facilities with full activated sludge based nitrogen removal processes, including both nitrification and denitrification, had high SVIs (>300 mL g(-1)) and were strongly affected by vacuum degassing with reduction of SVI up to 30%...
October 20, 2016: Environmental Technology
Siavash Isazadeh, Shameem Jauffur, Dominic Frigon
Effect of ecological variables on community assembly of heterotrophic bacteria at eight full-scale and two pilot-scale activated sludge wastewater treatment plants (AS-WWTPs) were explored by pyrosequencing of 16S rRNA gene amplicons. In total, 39 samples covering a range of abiotic factors spread over space and time were analyzed. A core bacterial community of 24 families detected in at least six of the eight AS-WWTPs was defined. In addition to the core families, plant-specific families (observed at <50% AS-WWTPs) were found to be also important in the community structure...
October 19, 2016: MicrobiologyOpen
Matthew D Hladilek, Karen F Gaines, James M Novak, David A Collard, Daniel B Johnson, Thomas Canam
Despite our dependency on treatment facilities to condition wastewater for eventual release to the environment, our knowledge regarding the effects of treated water on the local watershed is extremely limited. Responses of lotic systems to the treated wastewater effluent have been traditionally investigated by examining the benthic macroinvertebrate assemblages and community structure; however, these studies do not address the microbial diversity of the water systems. In the present study, planktonic and benthic bacterial community structure were examined at 14 sites (from 60 m upstream to 12,100 m downstream) and at two time points along an aquatic system receiving treated effluent from the Charleston Wastewater Treatment Plant (Charleston, IL)...
November 2016: Environmental Monitoring and Assessment
Mariana Governo, Mónica S F Santos, Arminda Alves, Luís M Madeira
Cytostatics are part of the forefront research topics due to their high prescription, high toxicity, and the lack of effective solutions to stop their entrance and spread in the environment. Among them, 5-Fluorouracil (5-Fu) has received particular attention because is one of the most prescribed active substances in chemotherapy worldwide. The degradation of 5-Fu by advanced oxidation processes (AOPs) is a poorly addressed topic, and this work brings valuable inputs concerning this matter. Herein, the efficacy of Fenton's process in the degradation of 5-Fu is explored for the first time; the study of the main variables and its successful application to the treatment of real wastewaters is demonstrated...
October 19, 2016: Environmental Science and Pollution Research International
Stefan C Weiss, Nicole Egetenmeyer, Wolfgang Schulz
Modern analytical test methods increasingly detect anthropogenic organic substances and their transformation products in water samples and in the environment. The presence of these compounds might pose a risk to the aquatic environment. To determine a possible (eco)toxicological risk, aquatic samples are tested using various bioassays, including sub-organismic assays such as the luminescent bacteria inhibition test, the acetylcholinesterase inhibition test, and the umu-test. The effect-directed analysis (EDA) combines physicochemical separation methods with biological (in vitro) tests...
October 19, 2016: Advances in Biochemical Engineering/biotechnology
Victoria N Deycard, Jörg Schäfer, Jérôme C J Petit, Alexandra Coynel, Laurent Lanceleur, Lionel Dutruch, Cécile Bossy, Alexandre Ventura, Gérard Blanc
Although silver (Ag) has been listed as a priority pollutant for the aquatic environment by the European Union (Directive 2006/11/EC), the use of Ag-based products with antimicrobial effects is increasing in Europe, as well as North America and Asia. This study investigates personal care products (PCP) as a potential source of Ag in wastewater, as well as the dynamics and fate of Ag in the influent and effluent of a major urban wastewater treatment plant (WWTP) located on the fluvial part of the Gironde Estuary...
October 15, 2016: Chemosphere
Prashant Praveen, Jonathan Yun Ping Heng, Kai-Chee Loh
Discharge of wastewater with high nitrogen and phosphorus content is a major cause of eutrophication. In this study, a microfiltration-based membrane photobioreactor (MPBR) and forward osmosis-based osmotic membrane photobioreactor (OMPBR) have been operated with Chlorella vulgaris for continuous tertiary wastewater treatment. Both the bioreactors exhibited good biomass accumulation (over 2g/L), although the OMPBR achieved better nutrients removal due to high rejection properties of the membranes. At 2days HRT, the OMPBR achieved nitrogen and phosphorus removal efficiencies of 86-99% and 100%, respectively, whereas the corresponding values in the MPBR were 48-97% and 46%, respectively...
October 1, 2016: Bioresource Technology
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