0000000000000378
AUTHOR
E. Jiménez
A new strategy to maximize organic matter valorization in municipalities: combination of urban wastewater with kitchen food waste and its treatment with AnMBR technology
[EN] The aim of this study was to evaluate the feasibility of treating the kitchen food waste (FW) jointly with urban wastewater (WW) in a wastewater treatment plant (WWTP) by anaerobic membrane technology (AnMBR). The experience was carried out in six different periods in an AnMBR pilot-plant for a total of 536 days, varying the SRT, HRT and the food waste penetration factor (PF) of food waste disposers. The results showed increased methane production of up to 190% at 70 days SRT, 24 hours HRT and 80% PF, compared with WW treatment only. FW COD and biodegradability were higher than in WW, so that the incorporation of FW into the treatment increases the organic load and the methane producti…
Short-term effect of ammonia concentration and salinity on activity of ammonia oxidizing bacteria.
A continuously aerated SHARON (single reactor high activity ammonia removal over nitrite) system has been operated to achieve partial nitritation. Two sets of batch experiments were carried out to study the effect of ammonia concentration and salinity on the activity of ammonia-oxidizing bacteria (AOB). Activity of AOB raised as free ammonia concentration was increased reaching its maximum value at 4.5 mg NH 3 -N l −1 . The half saturation constant for free ammonia was determined (K NH 3 = 0.32 mg NH 3 -N l −1 ). Activity decreased at TAN (total ammonium–nitrogen) concentration over 2,000 mg NH 4 -N l −1 . No free ammonia inhibition was detected. The effect of salinity was studied by adding…
Potential use of the organic fraction of municipal solid waste in anaerobic co-digestion with wastewater in submerged anaerobic membrane technology
Food waste was characterized for its potential use as substrate for anaerobic co-digestion in a submerged anaerobic membrane bioreactor pilot plant that treats urban wastewater (WW). 90% of the particles had sizes under 0.5 mm after grinding the food waste in a commercial food waste disposer. COD, nitrogen and phosphorus concentrations were 100, 2 and 20 times higher in food waste than their average concentrations in WW, but the relative flow contribution of both streams made COD the only pollutant that increased significantly when both substrates were mixed. As sulphate concentration in food waste was in the same range as WW, co-digestion of both substrates would increase the COD/SO4-S rat…
Milk and blood biomarkers associated to the clinical efficacy of a probiotic for the treatment of infectious mastitis
Previous studies have shown the efficacy of oral administration of selected lactobacilli strains to treat mastitis. The objective of this study was to find microbiological, biochemical and/or immunological biomarkers of the probiotic effect. Women with (n=23) and without (n=8) symptoms of mastitis received three daily doses (109 cfu) of Lactobacillus salivarius PS2 for 21 days. Samples of milk, blood and urine were collected before and after the probiotic intervention, and screened for a wide spectrum of microbiological, biochemical and immunological parameters. In the mastitis group, L. salivarius PS2 intake led to a reduction in milk bacterial counts, milk and blood leukocyte counts and i…
Impact of surgeon organization and specialization in rectal cancer outcome.
Purpose The present study was designed to assess the differences in the outcome of patients with rectal cancer treated by a group of surgeons before and after being organized as a Coloproctology Unit at the same University Department of Surgery. Methods Comparison of two periods of rectal cancer surgery: I (1986–91) and II (1992–95). Period I: 94 patients were operated on by 14 general surgeons. Period II: 108 patients were operated on by only 4 surgeons of the same group organized as a Colorectal Surgery Unit after visiting referral centres abroad, adopting techniques such as total mesorectal excision (TME) for middle and low rectal cancer and washout of rectal stump. Mean follow-up during…
Effect of pH, substrate and free nitrous acid concentrations on ammonium oxidation rate.
Respirometric techniques have been used to determine the effect of pH, free nitrous acid (FNA) and substrate concentration on the activity of the ammonium oxidizing bacteria (AOB) present in an activated sludge reactor. With this aim, bacterial activity has been measured at different pH values (ranging from 6.2 to 9.7), total ammonium nitrogen concentrations (ranging from 0.1 to 10 mg TAN L-1) and total nitrite concentrations (ranging from 3 to 43 mg NO2-N L-1). According to the results obtained, the most appropriate kinetic expression for the growth of AOB in activated sludge reactors has been established. Substrate half saturation constant and FNA and pH inhibition constants have been obt…
Anal endosonographic evaluation after closed lateral subcutaneous sphincterotomy
PURPOSE: The present study was undertaken to evaluate anal endosonographic results of the transverse and longitudinal extent of internal anal sphincter division after closed lateral subcutaneous sphincterotomy and its relationship to outcome with respect to anal fissure recurrence and postoperative anal incontinence. METHODS: Ten patients selected for symptomatic anal fissure recurrence (mean follow-up, 10.9 months) and 41 asymptomatic control patients (mean follow-up, 15.5 months) were reviewed by anal endosonography after closed lateral subcutaneous sphincterotomy. Clinical evaluation was focused on anal fissure recurrence and postoperative anal incontinence. The anal endosonographic stud…
Effect of pH and HNO2 concentration on the activity of ammonia-oxidizing bacteria in a partial nitritation reactor
Ammonia-oxidizing bacteria (AOB) are very sensitive to environmental conditions and wastewater treatment plant operational parameters. One of the most important factors affecting their activity is pH. Its effect is associated with: NH3/NH4 þ and HNO2/NO2 chemical equilibriums and biological reaction rates. The aim of this study was to quantify and model the effect of pH and free nitrous acid (FNA) concentration on the activity of AOB present in a lab-scale partial nitritation reactor. For this purpose, two sets of batch experiments were carried out using biomass from this reactor. Fluorescent in situ hybridization analysis showed that Nitrosomona eutropha and Nitrosomona europaea species we…
Biological Nutrient Removal Model No. 2 (BNRM2): a general model for wastewater treatment plants
This paper presents the plant-wide model Biological Nutrient Removal Model No. 2 (BNRM2). Since nitrite was not considered in the BNRM1, and this previous model also failed to accurately simulate the anaerobic digestion because precipitation processes were not considered, an extension of BNRM1 has been developed. This extension comprises all the components and processes required to simulate nitrogen removal via nitrite and the formation of the solids most likely to precipitate in anaerobic digesters. The solids considered in BNRM2 are: struvite, amorphous calcium phosphate, hidroxyapatite, newberite, vivianite, strengite, variscite, and calcium carbonate. With regard to nitrogen removal via…
Effect of pH and nitrite concentration on nitrite oxidation rate
The effect of pH and nitrite concentration on the activity of the nitrite oxidizing bacteria (NOB) in an activated sludge reactor has been determined by means of laboratory batch experiments based on respirometric techniques. The bacterial activity was measured at different pH and at different total nitrite concentrations (TNO 2). The experimental results showed that the nitrite oxidation rate (NOR) depends on the TNO 2 concentration independently of the free nitrous acid (FNA) concentration, so FNA cannot be considered as the real substrate for NOB. NOB were strongly affected by low pH values (no activity was detected at pH 6.5) but no inhibition was observed at high pH values (activity wa…