Search results for "Water Purification"
showing 10 items of 140 documents
Biological nutrient removal in membrane bioreactors: denitrification and phosphorus removal kinetics.
2007
The impact of including membranes for solid liquid separation on the kinetics of nitrogen and phosphorus removal was investigated. To achieve this, a membrane bioreactor (MBR) biological nutrient removal (BNR) activated sludge system was operated. From batch tests on mixed liquor drawn from the MBR BNR system, denitrification and phosphorus removal rates were delineated. Additionally the influence of the high total suspended solids concentrations present in the MBR BNR system and of the limitation of substrate concentrations on the kinetics was investigated. Moreover the ability of activated sludge in this kind of system to denitrify under anoxic conditions with simultaneous phosphate uptak…
The importance of Hygienics and Clean Water Treatment in Valencia (1860-1910)
2016
El siglo XIX se caracteriza por numerosos cambios tanto a nivel social como estructural de la población: se produce un acelerado desarrollo urbano sin planificación y carente de servicios que da lugar a una mala calidad de vida y numerosas epidemias. Estos cambios tienen como resultado un nuevo movimiento, el Higienismo, que pretende mejorar las condiciones de vida de la población. En España, todas las reformas higiénicas se desarrollaron mediante los planes de Ensanche. Uno de los puntos clave de este pensamiento es el abastecimiento de agua potable como medio para evitar enfermedades. La ciudad de Valencia es un claro ejemplo de la importancia de este movimiento y cómo el abastecimiento d…
Removal of bis (2-ethylhexyl) phthalate from reject water in a nitrogen-removing sequencing batch reactor.
2003
Reject water from sewage sludge processing may contain high concentrations of nutrients and organic pollutants and cause internal pollution load at a sewage treatment plant (STP) if circulated to the headworks of an STP. In the present study removal of nitrogen and bis (2-ethylhexyl) phthalate (DEHP) from reject water was studied in two sequencing batch reactors (SBRs) with different aerobic/anoxic periods during a 6-h total cycle period. Ammonia-nitrogen (NH(4)-N) was almost totally removed in both reactors, apparently by nitrification throughout the run, while denitrification declined with decreasing SCOD in the influent resulting in an increase in the effluent nitrate-nitrogen (NO(3)-N) …
Removal of bis(2-ethylhexyl) phthalate at a sewage treatment plant
2003
Bis(2-ethylhexyl) phthalate (DEHP) concentrations were measured at different stages in a full-scale sewage treatment plant (STP) and mass balances were calculated. The DEHP load to treatment process coming from the sewer system and the internal load comprising returned supernatants and filtrate from sludge treatment and excess secondary sludge were at the same level. The DEHP removal efficiency from the water phase at the STP was on average 94% of sewage DEHP, the main removal process being sorption to primary and secondary sludges. On average 29% of DEHP was calculated to be removed in the biological nitrifying-denitrifying activated sludge process, which was much less than expected from l…
Ammonium adsorption, desorption and recovery by acid and alkaline treated zeolite
2021
In this study, the suitability of zeolite as a possible medium for ammonium adsorption, desorption and recovery from wastewater was investigated. Specifically, batch adsorption and desorption studies with solutions enriched in NH$_4^+$ were conducted employing zeolite to evaluate how the chemical treatment and contact time affect adsorption and desorption. Several experimental tests were carried out considering both untreated and treated zeolite. Untreated and HCl-Na treated zeolite adsorbed up to 11.8 mg NH$_4^+$ g$^{-1}$ and showed the highest efficiency in recovering NH$_4^+$ from aqueous solution. Regardless of pre-treatment, treatments with NaCl resulted in higher and faster adsorption…
Preparation of polyelectrolyte-modified membranes for heavy metal ions removal
2017
ABSTRACTPolyethersulfone membranes were modified by polyelectrolyte (PE) multilayers, made of poly(allylamine hydrochloride) with poly(styrene sulfonate), to remove Cu2+, Zn2+ and Ni2+ heavy metal cations from aqueous solutions in a wide range of metal concentration (50–1200 ppm). After characterization of the modified membranes, the efficiency of the process was estimated for single heavy metal ions solution leading to high rejection rates (>90% for 50 ppm) and good adsorption capacities (7.0–8.5 mg cm−2) whatever the metal ion tested. The stability in time of the modified membranes was proved by repeating successive filtrations with the same membrane. The filtration process was also used …
Identifying Iron-Bearing Nanoparticle Precursor for Thermal Transformation into the Highly Active Hematite Photo-Fenton Catalyst
2020
Funding: This reseach was funded by the European Regional Development Fund within the Activity 1.1.1.2 “Post-doctoral Research Aid” of the Specific Aid Objective 1.1.1 “To increase the research and innovative capacity of scientific institutions of Latvia and the ability to attract external financing, investing in human resources and infrastructure” of the Operational Programme “Growth and Employment” (No. 1.1.1.2/VIAA/1/16/157).
Water Fluxes in Polymeric Membranes for Desalination via Membrane Distillation
2010
Membrane distillation is an emerging technique for seawater desalination. Hydrophobic polymeric membranes are used to separate the solute‐free water vapour from the hot solution. Vapour fluxes of commercial polymeric membranes were measured in various conditions, i.e. natural and forced convection and vacuum. Vapour fluxes were also predicted with models and compared with experimentals. Higher fluxes were recorded in vacuum conditions.
Effect of temperature on anaerobic treatment of black water in UASB-septic tank systems
2007
The effect of northern European seasonal temperature changes and low temperature on the performance of upflow anaerobic sludge blanket (UASB)-septic tanks treating black water was studied. Three UASB-septic tanks were monitored with different operational parameters and at different temperatures. The results indicated the feasibility of the UASB-septic tank for (pre)treatment of black water at low temperatures with respect to removal of suspended solids and dissolved organic material. Inoculum sludge had little effect on COD(ss) removal, though in the start-up phase some poorly adapted inoculum disintegrated and washed out, thus requiring consideration when designing the process. Removal of …
Particle balance and return loops for microplastics in a tertiary-level wastewater treatment plant.
2021
Highlights: Dewatering by centrifugation was a step that removed a high number of MPs from the sludge. Sludge retained especially the fibrous microplactics. Reject water transported microplastics inside a wastewater treatment plant. Disc filter-based tertiary treatment ensured removal of 99% of microplastics in wastewater. Microplastics (MPs) from households, stormwater, and various industries are transported to wastewater treatment plants (WWTPs), where a high proportion of them are captured before discharging their residuals to watersheds. Although recent studies have indicated that the removed MPs are mainly retained in wastewater sludge, sludge treatment processes have gained less atten…