Search results for "aerobic"
showing 10 items of 760 documents
Determination of pharmaceutical residues and assessment of their removal efficiency at the Daugavgriva municipal wastewater treatment plant in Riga, …
2017
Pharmaceutical products (PPs) belong to emerging contaminants that may accumulate along with other chemical pollutants in wastewaters (WWs) entering industrial and/or urban wastewater treatment plants (WWTPs). In the present study, the technique of ultra-high-performance liquid chromatography coupled to Orbitrap high-resolution mass spectrometry (Orbitrap-HRMS) was applied for the analysis of 24 multi-class PPs in WW samples collected at different technological stages of Daugavgriva WWTP located in Riga, Latvia. Caffeine and acetaminophen levels in the range of 7,570–11,403 ng/L and 810–1,883 ng/L, respectively, were the predominant compounds among 19 PPs determined in the WW. The results i…
Monitoring pH and electric conductivity in an EBPR sequencing batch reactor
2004
This paper presents laboratory-scale experimentation carried out to study enhanced biological phosphorus removal. Two anaerobic aerobic (A/O) sequencing batch reactors (SBR) have been operated during more than one year to investigate the information provided by monitoring pH and electric conductivity under stationary and transient conditions. Continuous measurements of these parameters allow detecting the end of anaerobic phosphorus release, of aerobic phosphorus uptake and of initial denitrification, as well as incomplete acetic acid uptake. These results suggest the possibility of using pH and electric conductivity as control parameters to determine the length of both anaerobic and aerobi…
Low cost-sensors as a real alternative to on-line nitrogen analysers in continuous systems.
2009
This paper is focused on the evaluation of the applicability of low-cost sensors (pH and ORP) versus nutrient analysers for controlling biological nitrogen removal in WWTPs. A nutrient removal pilot plant located in Carraixet WWTP (Valencia, Spain) that is equipped with a significant number of nutrient analysers and low-cost sensors was used. The relations between reliable, cheap on-line sensors such as pH and ORP (located in anaerobic, anoxic and aerobic zones) and the nitrification/denitrification processes are provided. The nitrification process can be evaluated by measuring the pH difference between the first and last aerobic zones. The denitrification process can be evaluated by measur…
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, …
Anaerobic on-site black water and kitchen waste treatment using UASB-septic tanks at low temperatures.
2006
Anaerobic on-site treatment of black water (BW) and a mixture of black water and kitchen waste (BWKW) was studied in a two-phased upflow anaerobic sludge blanket septic tank (UASBst) at 10–20 °C. The processes were fed either continuously or discontinuously (twice per weekday). Moreover, BWKW was post-treated for nitrogen removal in an intermittently aerated moving bed biofilm reactor (MBBR) at 20 °C. Removal of total chemical oxygen demand (CODt) was efficient at minimum 90% with all three UASBst at all temperatures. Removal of dissolved COD (CODdis) was also high at approx. 70% with continuously fed BW and discontinuously fed BWKW, while with discontinuous BW feeding it was 20%. Temperatu…
Pilot-scale thermophilic anaerobic treatment of wastewaters from seasonal vegetable processing industry
1997
Thermophilic anaerobic treatment of food industry wastewaters was studied using a 0.65 m3 upflow anaerobic sludge bed (UASB) reactor. The reactor was operated at 55°C and placed on the premises of a factory manufacturing deep-frozen goods from vegetables. The hot (>80-90°C) and concentrated (COD 14-79 g/l) wastewater streams, deriving from steam peeling and blanching of carrot and potato were used. The UASB reactor was inoculated with a small amount of granular sludge from a full-scale mesophilic UASB reactor. Prior to inoculation, the inoculum was acclimated to 55°C for 2 days. The reactor was fed with a mixture of wastewaters diluted to the desired COD. The reactor was started with loadin…
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…
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…
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…