Search results for " RETE"
showing 10 items of 346 documents
Mass loading, distribution, and removal of antibiotics and antiretroviral drugs in selected wastewater treatment plants in Kenya.
2020
The discharge of active pharmaceutical ingredients (APIs) into the aquatic environment from wastewater effluents is a concern in many countries. Although many studies have been conducted to evaluate the APIs removal efficiencies and emissions to the environment in wastewater treatment plants (WWTPs), most of these studies considered the aqueous and sludge phases, disregarding the suspended particulate matter (SPM) phase. To try to understand the role of the SPM, the occurrence of five most common antibiotics and three antiretroviral drugs (ARVDs) commonly used in Kenya were investigated in this study. APIs partitioning and mass loading in influents and effluents of three different WWTPs: tr…
Nitrous oxide from integrated fixed-film activated sludge membrane bioreactor: Assessing the influence of operational variables
2017
The influence of the main operational variables on N2O emissions from an Integrated Fixed Film Activated Sludge University of Cape Town membrane Bioreactor pilot plant was studied. Nine operational cycles (total duration: 340 days) were investigated by varying the value of the mixed liquor sludge retention time (SRT) (Cycles 1â3), the feeding ratio between carbon and nitrogen (C/N) (Cycles 4â6) and simultaneously the hydraulic retention time (HRT) and the SRT (Cycles 7â9). Results show a huge variability of the N2O concentration in liquid and off-gas samples (ranged from 10â1μg N2O-N Lâ1to 103μg N2O-N Lâ1). The maximum N2O concentration (1228 μg N2O-N Lâ1) in the off-gas sa…
Greenhouse gas emissions from membrane bioreactors: analysis of a two-year survey on different MBR configurations
2018
Abstract This study aimed at evaluating the nitrous oxide (N2O) emissions from membrane bioreactors (MBRs) for wastewater treatment. The study investigated the N2O emissions considering multiple influential factors over a two-year period: (i) different MBR based process configurations; (ii) wastewater composition (municipal or industrial); (iii) operational conditions (i.e. sludge retention time, carbon-to-nitrogen ratio, C/N, hydraulic retention time); (iv) membrane modules. Among the overall analysed configurations, the highest N2O emission occurred from the aerated reactors. The treatment of industrial wastewater, contaminated with salt and hydrocarbons, provided the highest N2O emission…
Treatment of a submerged anaerobic membrane bioreactor (SAnMBR) effluent by an activated sludge system: the role of sulphide and thiosulphate in the …
2014
This work studies the use of a well-known and spread activated sludge system (UCT configuration) to treat the effluent of a submerged anaerobic membrane bioreactor (SAnMBR) treating domestic waste-water. Ammonia, phosphate, dissolved methane and sulphide concentrations in the SAnMBR effluent were around 55 mg NH4-N L-1, 7 mg PO4-P L-1, 30 mg non-methane biodegradable COD L-1, and 105 mg S2- L-1 respectively. The results showed a nitrification inhibition caused by the presence of sulphur compounds at any of the solids retention time (SRT) studied (15,20 and 25 days). This inhibition could be overcome increasing the hydraulic retention time (HRT) from 13 to 26 h. Among the sulphur compounds, …
Maximising resource recovery from wastewater grown microalgae and primary sludge in an anaerobic membrane co-digestion pilot plant coupled to a compo…
2021
[EN] A pilot-scale microalgae (Chlorella spp.) and primary sludge anaerobic co-digestion (ACoD) plant was run for one year in an anaerobic membrane bioreactor (AnMBR) at 35 °C, 70 d solids retention time and 30 d hydraulic retention time, showing high stability in terms of pH and VFA concentration. The plant achieved a high degree of microalgae and primary sludge substrate degradation, resulting in a methane yield of 370 mLCH4·gVSinf¿1. Nutrient-rich effluent streams (685 mgN·L¿1 and 145 mgP·L¿1 in digestate and 395 mgNH4-N·L¿1 and 37 mgPO4-P·L¿1 in permeate) were obtained, allowing posterior nutrient recovery. Ammonium was recovered from the permeate as ammonia sulphate through a hydrophob…
Nitrification of anaerobically pretreated municipal landfill leachate at low temperature
2000
Abstract Nitrification of anaerobically pretreated municipal landfill leachate (270–1000 mg COD l −1 , 53–270 mg NH 4 –N l −1 ) was studied in laboratory-scale activated sludge reactors without (AS) and with (ASC) the addition of plastic carrier material. The reactors were run at 10°C (149 d), 7°C (21 d) and 5°C (16 d). With a loading rate of 0.027 g NH 4 –N g MLVSS −1 d −1 and a hydraulic retention time of ca. 3 d, at 10°C, complete nitrification was obtained in both reactors. At 7°C, and in loading rate of 0.023 g NH 4 –N g MLVSS −1 d −1 , both reactors appeared to be overloaded and ammonium removal was only ca. 93%. At 5°C, with a lower loading rate of 0.010 g NH 4 –N g MLVSS −1 d −1 …
Effect of additives on process stability of mesophilic anaerobic monodigestion of pig slaughterhouse waste
2012
The effect of two additives on anaerobic monodigestion of pig slaughterhouse waste was studied in three laboratory scale continuously stirred tank reactors (CSTRs) operated for 242-284 days at 35°C. A higher organic loading rate (OLR), namely 2.25 kg volatile solids (VS)/m(3)d with a hydraulic retention time (HRT) of 30 d was feasible with an additive containing Fe, HCl and trace elements while an OLR of 1.5 kg VS/m(3)d (HRT 30 d) led to instabilities in CSTR with an additive consisting of Fe and HCl and in CSTR without additives. Methane yields of ca. 700 dm(3) CH(4)/kg VS(fed) were obtained in all reactors under stable conditions. Both additives decreased H(2)S concentration of the biogas…
Nitrous oxide from moving bed based integrated fixed film activated sludge membrane bioreactors
2017
Abstract The present paper reports the results of a nitrous oxide (N 2 O) production investigation in a moving bed based integrated fixed film activated sludge (IFAS) membrane bioreactor (MBR) pilot plant designed in accordance with the University of Cape Town layout for biological phosphorous removal. Gaseous and liquid samples were collected in order to measure the gaseous as well as the dissolved concentration of N 2 O. Furthermore, the gas flow rate from each reactor was measured and the gas flux was estimated. The results confirmed that the anoxic reactor represents the main source of nitrous oxide production. A significant production of N 2 O was, however, also found in the anaerobic …
Semi-continuous anaerobic digestion of solid poultry slaughterhouse waste: effect of hydraulic retention time and loading.
2002
Abstract We studied the effect of hydraulic retention time (HRT) and loading on anaerobic digestion of poultry slaughterhouse wastes, using semi-continuously fed, laboratory-scale digesters at 31°C. The effect on process performance was highly significant: Anaerobic digestion appeared feasible with a loading of up to 0.8 kg volatile solids (VS)/m 3 d and an HRT of 50–100 days. The specific methane yield was high, from 0.52 to 0.55 m 3 /kg VS added . On the other hand, at a higher loading, in the range from 1.0 to 2.1 kg VS/m 3 d, and a shorter HRT, in the range from 25 to 13 days, the process appeared inhibited and/or overloaded, as indicated by the accumulation of volatile fatty acids an…
Co-digestion of manure and biowaste according to the EC Animal By-Products Regulation and Finnish national regulations
2006
The objective of this study was to compare methane production and characteristics of digested material in anaerobic digestion concepts according to the Animal By-Products Regulation (ABP-Regulation) of the EC (hygienisation of biowaste for 1 hour at 70 °C, particle size <12 mm) and Finnish national regulations (treatment temperature 55 °C, feeding interval 24 h, hydraulic retention time (HRT) 20 d, particle size <40 mm) and with small variations in treatment methods for treating manure and biowaste. Moreover, the survival of three different salmonella bacteria in these processes was studied. Hygienisation of biowaste prior to digestion at 35 °C enhanced methane production by 1…