8 research outputs found

    Evaluation of factors affecting the performance of biological phosphorus removal in a full-scale wastewater treatment plant

    Full text link
    Parameters bearing on the performance of a full-scale 88-MGD enhanced biological phosphorus removal (EBPR) system were examined. Samples were collected for a 10-month period in a basin and in a secondary clarifier of the plant. Samples were analyzed for nitrate, total and ortho-phosphorus, COD, acetic acid, polyhydroxybutyrate, glycogen, calcium, magnesium, potassium, ammonia, alkalinity, TSS, ORP, pH, and DO. Profiles of the aerobic and anaerobic zones, and secondary clarifier showed that the plant is operating as an actual EBPR system, with sporadic phosphorus excursions. Low BOD input to the system, high phosphorus from return streams of the sludge handling process, high nitrates in the RAS, and strong denitrification in the secondary clarifiers were identified as potential causes for the occasional excursions. A correlation was found between TSS and nitrate concentrations in the RAS, indicating that the former may serve as a good parameter for controlling denitrification in secondary clarifiers

    Dinamic of pathogenic protozoa and cyanobacteria in a reservoir used for water supply in southeastern Brazil

    Get PDF
    O presente estudo foi baseado no monitoramento de um reservat√≥rio tropical (Vargem das Flores) utilizado para o abastecimento p√ļblico de √°gua de sete cidades da regi√£o metropolitana de Belo Horizonte, Minas Gerais. O reservat√≥rio foi monitorado durante quatro anos: per√≠odo inicial (de 2004 a 2007) para c√©lulas de cianobact√©rias e par√Ęmetros f√≠sico-qu√≠micos e, subsequentemente (2007 e 2008), para oocistos de Cryptosporidium spp. e cistos de Giardia spp. em quatro esta√ß√Ķes de amostragem. Tamb√©m foram avaliadas as concentra√ß√Ķes de Escherichia coli de 2007 a 2008, o que permitiu a caracteriza√ß√£o de cada ponto de amostragem de acordo com a legisla√ß√£o do Conselho Nacional do Meio Ambiente (CONAMA) n¬ļ 274/2000. Os resultados indicaram concentra√ß√Ķes de (oo)cistos de Cryptosporidium spp. e Giardia spp. variando de 0 a 0,8 (oo)cistos.L-1, e as mais elevadas concentra√ß√Ķes de c√©lulas de cianobact√©rias, de 0,0 a 4,5 x 105 cels.mL-1, apontando assim para potencial risco √† sa√ļde humana caso a √°gua do reservat√≥rio seja consumida sem tramento. As cianobact√©rias n√£o foram encontradas durante a esta√ß√£o seca. O grupo retornou rapidamente ap√≥s a desestratifica√ß√£o. A esta√ß√£o chuvosa foi caracterizada pela elevada ocorr√™ncia de cianobact√©rias com a predomin√Ęncia da esp√©cie picoplanct√īnica (Aphanocapsa sp.), sobre Microcystis spp. previamente detectada, e apresentou as maiores varia√ß√Ķes de oxig√™nio dissolvido, turbidez, f√≥sforo total, ortofosfato, am√īnia, nitrito e nitrato. A mudan√ßa observada no grupo das cianobact√©rias (Aphanocapsa spp. sobre Microcystis spp.) pode ser um indicativo das altera√ß√Ķes das caracter√≠sticas da √°gua. De acordo com as concentra√ß√Ķes de E. coli , as esta√ß√Ķes foram classificadas como pr√≥prias para recrea√ß√£o de contato prim√°rio, de acordo com a Resolu√ß√£o CONAMA n¬ļ 274/2000.The current study monitored the water quality of a tropical reservoir (Vargem das Flores) used to supply potable water to seven cities in the metropolitan area of Belo Horizonte, Minas Gerais, southeast Brazil. The reservoir was monitored for four years: initially (from 2004 to 2007) for cyanobacterial cells and physicochemical parameters and, subsequently (in 2007 and 2008), for Cryptosporidium spp. oocysts and Giardia spp. cysts in four sampling stations. The concentrations of Escherichia coli were also measured in 2007 and 2008, wich allowed the characterization of each sampling point according to the National Environment Council (CONAMA) no. 274/2000. Results indicated concentrations of Cryptosporidium spp. and Giardia spp. (oo)cysts ranging from 0 to 0.8 (oo)cysts.L-1, and higher concentrations of cyanobacteria cells, from 0.0 to 4.5 x 105 cells.mL-1, thus indicating potential risks to human health, if the water from the reservoir is not properly treated before consumption. The group of cyanobacteria was not found during the dry season, returning soon after destratification. The rainy season was characterized by a higher ocurrence of cyanobacteria and predominance of picoplanktonic species (Aphanocapsa spp.), over the Microcystis spp. previously found and presented the highest variations in dissolved oxygen, turbidity, total phosphorous, orthophosphate, ammonia, nitrite and nitrate. The change observed within the group of cyanobacteria (Aphanocapsa spp. over Microcystis spp.) may be indicative of changing characteristics in the water source. All the sampling points were classified as adequate for primary contact recreation, given the E. coli concentrations, according to the CONAMA Resolution no. 274/2000

    Polyhydroxyalkanoates (PHA) production from biogas in waste treatment facilities: Assessing the potential impacts on economy, environment and society

    No full text
    Producci√≥n Cient√≠ficaUsing the biogas generated from organic waste anaerobic treatment to produce polyhydroxyalkanoates (PHAs) has emerged as an attractive alternative to heat and power generation (CHP) in waste treatment plants. The sustainability of biogas combustion for CHP, biogas bioconversion into PHA and a combination of both scenarios was compared in terms of environmental impact, process economics and social responsibility according to the IChemE Sustainability Metrics. Although PHA production presented higher investment and operational costs, a comparable economic performance was observed in all biogas valorization scenarios regarding net present value (0.77 M‚ā¨) and internal rate of return (6.4 ¬Ī 0.2%) due to the higher market value of biopolymers. The PHA production entailed a significant reduction of atmospheric acidification and odor emissions compared to CHP despite showing higher land, water, chemicals and energy requirements. Job creation associated to biopolymer industry and the increasing public demand for bioproducts were identified as fundamental aspects for enhancing social and local acceptance of waste processing facilities. This study demonstrated that PHA production from biogas constitutes nowadays a realistic alternative to CHP in waste treatment plants and that PHA can be produced at a competitive market price when biogas is used for internal energy provision (4.2 ‚ā¨¬∑kg‚ąí1 PHA).Bio Based Industries Joint Undertaking (grant 745785)Junta de Castilla y Le√≥n - Fondo Europeo de Desarrollo Regional (grants CLU 2017‚Äď09, UIC 71 and VA281P18)Junta de Castilla y Le√≥n (grant C18IPJCL)European Union‚Äôs Horizon 2020 research and innovation programme under grant agreement No 74578

    Nature-based solutions for wastewater treatment and bioenergy recovery: a comparative Life Cycle Assessment

    No full text
    The aim of this study was to assess the environmental impacts of up-flow anaerobic sludge blanket (UASB) reactors coupled with high rate algal ponds (HRAPs) for wastewater treatment and bioenergy recovery using the Life Cycle Assessment (LCA) methodology. This solution was compared with the UASB reactor coupled with other consolidated technologies in rural areas of Brazil, such as trickling filters, polishing ponds and constructed wetlands. To this end, full-scale systems were designed based on experimental data obtained from pilot/demonstrative scale systems. The functional unit was 1 m3 of water. System boundaries comprised input and output flows of material and energy resources for system construction and operation. The LCA was performed with the software SimaPro¬ģ, using the ReCiPe midpoint method. The results showed that the HRAPs scenario was the most environmentally friendly alternative in 4 out of 8 impact categories (i.e. Global warming, Stratospheric Ozone Depletion, Terrestrial Ecotoxicity and Fossil resource scarcity). This was associated with the increase in biogas production by the co-digestion of microalgae and raw wastewater, leading to higher electricity and heat recovery. From an economic point of view, despite the HRAPs showed a higher capital cost, the operation and maintenance costs were completely offset by the revenue obtained from the electricity generated. Overall, the UASB reactor coupled with HRAPS showed to be a feasible nature-based solution to be used in small communities in Brazil, especially when microalgae biomass is valorised and used to increase biogas productivity.The research was funded by the National Council for Scientific and Technological Development from Brazilian Ministry of Education ‚Äď CNPq, the Reference Centre of Sustainable Sewage Treatment Plants - CR ETES, the Institute of Sustainable Sewage Treatment Plants - INCT ETEs, the Coordination for the Improvement of Higher Education Personnel ‚Äď CAPES, the Foundation for Research of the State of Minas Gerais ‚Äď FAPEMIG, and the CNPQ and to National Health Foundation ‚Äď FUNASA from Brasil. Lucas Vassalle is grateful to the CNPQ (scholarship 204026/2018-0). Ivet Ferrer and Marianna Garf√≠ are grateful to the Government of Catalonia (Consolidated Research Group 2017 SGR 1029), and Marianna Garf√≠ to the Spanish Ministry of Economy and Competitiveness (RYC-2016 20059).Peer ReviewedObjectius de Desenvolupament Sostenible::7 - Energia Assequible i No ContaminantObjectius de Desenvolupament Sostenible::6 - Aigua Neta i SanejamentPostprint (author's final draft

    Behavior of micropollutants in polishing units that combine sorption and biodegradation mechanisms to improve the quality of activated sludge effluent.

    No full text
    The current study evaluated the removal of six micropollutants (estrone (E1); 17?-estradiol (E2); 17?-ethynylestradiol (EE2); ibuprofen (IBP), diclofenac (DCF), and paracetamol (PCT)) from the final effluent of an activated sludge domestic sewage treatment plant using polishing filters. Four polishing filters were assembled as columns and filled with a mixture of sand and vermiculite, sand and charcoal, sand and granulated activated carbon (9:1 by volume), and sand only. The column filters were placed near the outlet of a full-scale activated sludge treatment plant and were fed with a treated effluent containing from 4.71 to 28.93 ng L-1 of the target compounds at a hydraulic loading rate (HLR) of 50 m3 m?2 day?1. Samples were collected periodically from the influent (biologically treated sewage) and effluent of the four columns and analyzed for estrogens, anti-inflammatories, and analgesic compounds. Liquid samples were submitted to a solid phase extraction (SPE) and analyzed by gas chromatography coupled with mass spectrometry after their derivatization. Among the compounds found, diclofenac was distinguished by the high occurrence of detection in the samples (85%) and higher mean concentration (~?17 ng L?1). High removal efficiency (>?90%) of the estrogens was observed in the polishing systems studied, while for the other targets, the removal efficiency varied from 10 to 30%. The concentration values of some compounds were low, probably due to rainfall during the sampling period
    corecore