Dynamics in maximal settling capacity in an activated sludge treatment plant with highly loaded secondary settlers

2004 ◽  
Vol 50 (7) ◽  
pp. 187-194 ◽  
Author(s):  
B.-M. Wilén ◽  
D. Lumley ◽  
A. Nordqvist
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Treatment Plant ◽  
Secondary Effluent ◽  
Sludge Treatment ◽  
Trickling Filters ◽  
Secondary Settling ◽  
Determining Factor ◽  
Maximal Capacity ◽  
Highly Loaded

Secondary settling dynamics at maximal capacity were investigated at a full scale wastewater treatment plant which utilizes a unique process solution incorporating pre-denitrification with postnitrification in nitrifying trickling filters. Since nitrogen removal is greater when more secondary effluent is recirculated to the trickling filters, the secondary settlers generally operate at close to their maximal capacity. The settling and flocculation properties of the activated sludge are therefore a major capacity-determining factor for plant operation. Due to the short sludge age, the flocculation properties, with respect to both thickening and clarification, can change quickly. The dynamics in these changes were studied and the factors that determine the maximal settling capacity were assessed. Solids flux curves were constructed from batch settling tests and compared with the actual maximal settling capacities.

Using metazoa to reduce sludge production

1997 ◽  
Vol 36 (11) ◽  
pp. 171-179 ◽  
Author(s):  
J. H. Rensink ◽  
W. H. Rulkens
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Domestic Wastewater ◽  
Brewery Wastewater ◽  
Trickling Filters ◽  
Starting Point ◽  
Nitrification Process ◽  
Sludge Production

Pilot plant experiments have been carried out to study the mineralization of sludge from biological wastewater treatment plants by worms such as Tubificidae. Trickling filters filled with lava slags were continuously fed with a certain quantity of excess activated sludge of a Dutch brewery wastewater treatment plant (Bavaria) by recirculation during 10 to 14 days. At the starting point of each experiment the trickling filters were inoculated with Tubificidae. Recirculation of sludge showed that use of Tubificidae resulted in a COD reduction of the sludge (mixed liquor) of 18–67–. Without worms this reduction was substantially lower. The sludge production in a pilot activated sludge system for treating settled domestic wastewater reduced from 0.40 to 0.15 g MLSS/g COD removed when Tubificidae were added to the system. The lower amounts of sludge were always accompanied by an increase of nitrate and phosphate concentration in the wastewater. There was no disturbance of the nitrification process. Application of Tubificidae or other worms may have interesting potential for practical application.

Full-scale control of Mycolata foam by FEX-120 addition

2010 ◽  
Vol 61 (10) ◽  
pp. 2443-2450 ◽  
Author(s):  
C. Kragelund ◽  
B. Nilsson ◽  
K. Eskilsson ◽  
A. M. Bøgh ◽  
P. H. Nielsen
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
No Reduction ◽  
Treatment Plant ◽  
Full Scale ◽  
Filamentous Bacteria ◽  
Gram Positive ◽  
Sludge Treatment ◽  
Scale Control

Foaming incidents in activated sludge treatment plants are a worldwide problem and occur on a regular basis in both municipal and industrial activated sludge treatment plants. Foaming is most often caused by excessive growth of filamentous bacteria, especially the gram-positive ones affiliated within the Actinobacteria, e.g. the branched Mycolata or CandidatusMicrothrix parvicella. Previous studies have shown that populations of Microthrix can be controlled by addition of certain polyaluminium compounds, but until now no effective chemicals have been identified to control other important foam formers such as the Mycolata. A new chemical (FilamentEx, FEX-120) was tested in full-scale in a Swedish wastewater treatment plant (WWTP) with immense foaming problems. In total, three different dosing events were carried out for more than 1 year. After only 8–17 weeks in each period, all foam had disappeared, and dosing of FEX-120 was stopped. Another 11 full-scale WWTPs in different countries were treated with FEX-120 because of severe Mycolata foaming on process tanks. In nine out of 11 plants, where the causative organisms were Gordonia or Skermania, a significant reduction of foam up to 100% was observed after treatment for approx. 10 weeks. In two WWTPs with unknown Mycolata organisms, no reduction was observed.

Polycyclic and Nitro Musks in Canadian Municipal Wastewater: Occurrence and Removal in Wastewater Treatment

2007 ◽  
Vol 42 (3) ◽  
pp. 138-152 ◽  
Author(s):  
Shirley Anne Smyth ◽  
Lori A. Lishman ◽  
Edward A. McBean ◽  
Sonya Kleywegt ◽  
Jian-Jun Yang ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Waste Activated Sludge ◽  
Secondary Effluent ◽  
Cold Temperatures ◽  
Primary Sludge ◽  
Polycyclic Musks ◽  
Nitro Musks

Abstract The removal and/or partitioning (to sludge) of six polycyclic and five nitro musks through the liquid treatment train of a conventional Canadian secondary activated sludge wastewater treatment plant is characterized. Raw influent, primary effluent, secondary effluent, primary sludge, and waste activated sludge concentrations were correlated to seasonal process temperatures (warm, 22°C; cold, 15°C). Maximum influent concentrations of polycyclic and nitro musks were 7,030 ± 2,120 ng/L for Galaxolide (HHCB) and 158 ± 89 ng/L for musk ketone respectively. Maximum secondary effluent concentrations were 2,000 ± 686 ng/L for HHCB and 51 ± 14 ng/L for musk ketone. Temperature appeared to influence the degree of removal of musks from wastewater during primary clarification (40% median removal at warm temperatures and 9% at cold temperatures) and overall treatment (82% median removal at warm temperatures and 74% at cold temperatures) but not secondary activated sludge treatment (71% median removal at warm temperatures and 70% at cold temperatures). In primary sludge, polycyclic musks were found at concentrations up to 35,000 ng/g for HHCB, and nitro musks were found at concentrations up to 490 ng/g for musk ketone. In waste activated sludge, polycyclic musks were found at concentrations up to 52,000 ng/g (HHCB), and nitro musks were found at concentrations up to 1,100 ng/g (musk ketone). The hydraulic retention time and the suspended solids of the treatment process appeared to influence the degree of partitioning of musks to sludge.

scholarly journals Combining Unmanned Aircraft Systems and Image Processing for Wastewater Treatment Plant Asset Inspection

2020 ◽  
Vol 12 (9) ◽  
pp. 1461
Author(s):  
Jorge Sancho Martínez ◽  
Yadira Bajón Fernández ◽  
Paul Leinster ◽  
Mónica Rivas Casado
Keyword(s):  
Image Processing ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Trickling Filters ◽  
Aircraft Systems

Wastewater treatment plants are essential for preserving the water quality of freshwater and marine ecosystems. It is estimated that, in the UK, as much as 11 billion liters of wastewater are treated on a daily basis. Effective and efficient treatment of wastewater requires treatment plants to be maintained in good condition. Recent studies have highlighted the potential of unmanned aircraft systems (UASs) and image processing to be used in autonomous and automated monitoring systems. However, the combined use of UASs and image processing for wastewater treatment plant inspections has not yet been tested. This paper presents a novel image processing-UAS framework for the identification of failures in trickling filters and activated sludge facilities. The results show that the proposed framework has an accuracy of 95% in the detection of failures in activated sludge assets, with the accuracy ranging between 55% and 81% for trickling filters. These results are promising and they highlight the potential use of the technology for the inspection of wastewater treatment plants.

Performance intensification of Prague wastewater treatment plant

2004 ◽  
Vol 50 (7) ◽  
pp. 139-146 ◽  
Author(s):  
L. Novák ◽  
D. Havrlíková
Keyword(s):  
Wastewater Treatment ◽  
Mathematical Modelling ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Chemical Precipitation ◽  
Plant Performance ◽  
Sludge Disposal ◽  
Secondary Settling ◽  
Raw Wastewater

Prague wastewater treatment plant was intensified during 1994-1997 by construction of new regeneration tank and four new secondary settling tanks. Nevertheless, more stringent effluent limits and operational problems gave rise to necessity for further intensification and optimisation of plant performance. This paper describes principal operational problems of the plant and shows solutions and achieved results that have lead to plant performance stabilisation. The following items are discussed: low nitrification capacity, nitrification bioaugmentation, activated sludge bulking, insufficient sludge disposal capacity, chemical precipitation of raw wastewater, simultaneous precipitation, sludge chlorination, installation of denitrification zones, sludge rising in secondary settling tanks due to denitrification, dosage of cationic polymeric organic flocculant to secondary settling tanks, thermophilic operation of digestors, surplus activated sludge pre-thickening, mathematical modelling.

Behaviour and Modelling of NTA Degradation in Activated Sludge Systems

1989 ◽  
Vol 21 (4-5) ◽  
pp. 315-324 ◽  
Author(s):  
H. Siegrist ◽  
A. Alder ◽  
W. Gujer ◽  
W. Giger
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Water Discharge ◽  
Treatment Plant ◽  
Secondary Effluent ◽  
Biological Degradation ◽  
Q 55 ◽  
Q 14 ◽  
The City ◽  
Daily Load

The general model for single-sludge wastewater treatment systems of the IAWPRC task group (Henze et al., 1987) was extended to describe the biological degradation of NTA and adsorption of NTA onto activated sludge based on literature studies and experiments undertaken at the Glatt wastewater treatment plant (waste water discharge: Q = 55 - 60 000 m3/d, 110 000 inhabitants) for the city of Zurich. During two days, the behaviour and diurnal load variation of nitrilotriacetate (NTA), zinc, lead and copper were analyzed on one lane (volume = 1 812 m3, Q = 14 700 m3/d) of the four parallel lanes used in secondary treatment. The plant had a sludge age of about 3.6 days and was partly nitrifying (wastewater temperature = 10-11 °C). The average daily load of NTA for the investigated lane was 14 kg NTA/d, corresponding to 0.5 g NTA/person.d. The influent concentration varied between 300 and 1 500 µg NTA/l. NTA was biologically degraded up to 97 %. Between 12 am and 2 pm of the second day 17 kg NTA (120 % of the daily load of one lane) had been added to the primary effluent. During 4 to 5 hours the biological NTA degradation was saturated and four times more than the daily average of NTA was degraded. Zinc and lead did increase in the secondary effluent during the NTA shock loading.

scholarly journals Removal of organic micropollutants in the biological units of a Swedish wastewater treatment plant

2021 ◽  
Vol 1209 (1) ◽  
pp. 012016
Author(s):  
C Burzio ◽  
E Nivert ◽  
A Mattsson ◽  
O Svahn ◽  
F Persson ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Organic Micropollutants ◽  
Trickling Filters ◽  
Biofilm Reactors ◽  
Micropollutant Removal ◽  
Activated Sludge Reactor

Abstract The present study investigates the presence and removal of target organic micropollutants in a large Swedish wastewater treatment plant designed for nutrient removal including activated sludge, trickling filters, nitrifying moving bed biofilm reactors (MBBRs) and post-denitrifying MBBRs. A total of 28 organic micropollutants were analysed, at concentrations ranging from few ng/L to µg/L, in the influent and effluent of the different biological reactors in two sampling campaigns. The observed micropollutant removal efficiencies of the wastewater treatment plant varied from insignificant (< 20%) to high (> 90%) between compounds. The activated sludge reactor, being the first in line, contributed to most of the removal from the water phase. Additional removal of a few compounds was observed in the biofilm units, but most of the persistent compounds remained stable through all biological treatments.

Ten Years Experience with a Highly Loaded Activated Sludge Plant

1984 ◽  
Vol 16 (12) ◽  
pp. 649-660
Author(s):  
P Balmér ◽  
S Hallquist ◽  
M Hernebring
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Residence Time ◽  
Suspended Solids ◽  
Treatment Plant ◽  
Volume Index ◽  
Sludge Volume Index ◽  
Solids Concentration ◽  
Cell Residence Time ◽  
Highly Loaded

The Rya wastewater treatment plant in Gothenburg, Sweden serves 640 000 population equivalents. It is an extremely highly loaded activated sludge plant without presetting with a mean cell residence time of about 0.5 days. Ten years experience proves that the plant is capable of removing about 70% of the BOD load. The effluent BOD is mainly caused by non settleable suspended solids due to the partly dispersed growth of the activated sludge. The low mean cell residence time and the high suspended solids concentration in the aeration basin influent gives an activated sludge with low viability and in mass balance studies it was determined that only 12% of the influent COD and about 40% of the BOD was oxidized by the activated sludge. The activated sludge has consistently had a very low sludge volume index and the settling basins could thus be very highly loaded. The surplus activated sludge could be thickened to solids concentrations over 6%. After dewatering the sludge was either lime treated or co-composted with bark. The plant is manned only eight hours five days a week. During unmanned time there are standby personnel. Data is presented on man power, energy and chemical use, and on costs.

Removal and inactivation of cryptosporidium oocysts by activated sludge treatment and anaerobic digestion

1995 ◽  
Vol 31 (5-6) ◽  
pp. 97-104 ◽  
Author(s):  
K. L. Stadterman ◽  
A. M. Sninsky ◽  
J. L. Sykora ◽  
W. Jakubowskii
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Sewage Treatment ◽  
Treatment Plant ◽  
Sludge Treatment ◽  
Treatment Processes ◽  
Secondary Effluents ◽  
Immunofluorescent Technique ◽  
Cryptosporidium Parvum Oocysts

To determine the fate of Cryptosporidium parvum oocysts during wastewater treatment, a model of an activated sludge treatment plant was designed with a flow of 17 ml/min and a detention time of 6 hours. Samples of raw sewage were seeded with oocysts and primary and secondary effluents were analyzed for C. parvum using an immunofluorescent technique. To compare removal efficiencies of oocysts by various wastewater treatment processes, raw sewage, activated sludge, trickling filter and biodisc effluents were seeded with oocysts and settled for 2 hr and for the respective detention times. Sludge produced by a wastewater treatment plant and anaerobically digested at 37° C in a laboratory digester was also seeded with C. parvum oocysts. Oocyst inactivation was measured by excystation and direct counts. Removal of oocysts in primary and secondary sedimentation averaged 83.4% and 90.7% respectively. The total oocyst removal in sewage treatment averaged 98.6%. In comparison with other treatment processes, activated sludge had the maximum oocyst removal efficiency at 92%. The anaerobic digestion process inactivated 90% of the oocysts within four hours of exposure. 99.9% of the oocysts were eliminated by anaerobic digestion after 24 hours. This demonstrates that the activated sludge process and anaerobic digestion can be effective for the removal and inactivation of C. parvum oocysts.

Thermophilic process and enhancement of excess activated sludge degradability – two ways of intensification of sludge treatment in the Prague central wastewater treatment plant

2000 ◽  
Vol 41 (9) ◽  
pp. 265-272 ◽  
Author(s):  
J. Zábranská ◽  
M. Dohányos ◽  
P. Jenícek ◽  
J. Kutil
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Full Scale ◽  
Methane Yield ◽  
Sludge Treatment ◽  
Cell Lysate ◽  
Full Scale Experiment ◽  
Scale Experiment

The paper describes two ways of intensification of sludge treatment in the Prague Central Wastewater Treatment Plant: full-scale experiment with thermophilic anaerobic digestion and full-scale experiment with lysis thickening centrifuge. Increasing temperature from the mesophilic to thermophilic level in the full-scale digesters leads to a better utilization of the existing facilities and consequently avoids digester overloading. The higher degradation efficiency is associated with higher biogas production and improvement of the energy balance of the process. Due to a careful and slow increasing of the operating temperature the thermophilic process was very stable. The partial destruction of excess activated sludge cells during the thickening by means of a lysis-thickening centrifuge produces cell lysate. The presence of the cell lysate in thickened excess activated sludge causes a substantial increment in the methane yield and the biodegradability of thickened activated sludge in comparison with untreated excess sludge. The improvement of methane yield from thickened activated sludge was on average 11.5–31.3% dependent on the sludge quality. The operation of lysis-thickening centrifuges in the Prague Central Wastewater Treatment Plant proved the possibility of full-scale application of the disintegration method.

Sign in / Sign up

Export Citation Format

Share Document