Integration of sulphate reduction, autotrophic denitrification and nitrification to achieve low-cost excess sludge minimisation for Hong Kong sewage

2006 ◽  
Vol 53 (3) ◽  
pp. 227-235 ◽  
Author(s):  
G.N. Lau ◽  
K.R. Sharma ◽  
G.H. Chen ◽  
M.C.M. van Loosdrecht
Keyword(s):  
Low Cost ◽  
Nitrate Solution ◽  
Integrated Treatment ◽  
Treatment System ◽  
Upflow Anaerobic Sludge Blanket ◽  
Synthetic Wastewater ◽  
Anaerobic Sludge ◽  
Autotrophic Denitrification ◽  
Excess Sludge ◽  
Anaerobic Reactor

An integrated anaerobic–aerobic treatment system of sulphate-laden wastewater was proposed here to achieve low sludge production, low energy consumption and effective sulphide control. Before integrating the whole system, the feasibility of autotrophic denitrification utilising dissolved sulphide produced during anaerobic treatment of sulphate rich wastewater was studied here. An upflow anaerobic sludge blanket reactor was operated to treat sulphate-rich synthetic wastewater (TOC = 100 mg/L and sulphate = 500 mg/L) and its effluent with dissolved sulphide and external nitrate solution were fed into an anoxic biofilter. The anaerobic reactor was able to remove 77–85% of TOC at HRT of 3 h and produce 70–90 mg S/L sulphide in dissolved form for the subsequent denitrification. The performance of anoxic reactor was stable, and the anoxic reactor could remove 30 mg N/L nitrate at HRT of 2 h through autotrophic denitrification. Furthermore, sulphur balance for the anoxic filter showed that more than 90% of the removed sulphide was actually oxidised into sulphate, thereby there was no accumulation of sulphur particles in the filter bed. The net sludge productions were approximately 0.15 to 0.18 g VSS/g COD in the anaerobic reactor and 0.22 to 0.31 g VSS/g NO3−-N in the anoxic reactor. The findings in this study will be helpful in developing the integrated treatment system to achieve low-cost excess sludge minimisation.

scholarly journals Reduction of scum accumulation through the addition of low-cost enzymatic extract in the feeding of high-rate anaerobic reactor

2019 ◽  
Vol 80 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Juliana Lemos Soares ◽  
Magali Christe Cammarota ◽  
Melissa Limoeiro Estrada Gutarra ◽  
Isaac Volschan
Keyword(s):  
Accumulation Rate ◽  
Low Cost ◽  
Hydrolytic Enzymes ◽  
High Rate ◽  
Upflow Anaerobic Sludge Blanket ◽  
Synthetic Wastewater ◽  
Anaerobic Sludge ◽  
Oil And Grease ◽  
Enzymatic Extract ◽  
Uasb Reactors

Abstract This work evaluates the reduction of scum accumulation on the top surface of upflow anaerobic sludge blanket (UASB) reactors by the addition of hydrolytic enzymes in their feed. For over 1 year, two UASB reactors of 1.4 L were maintained at 30 °C and continuously fed with synthetic domestic wastewater (containing 150 mg/L of soybean oil) under a hydraulic retention time of 10 h. The Control reactor was only fed with synthetic wastewater. Beginning at the 226th day of operation, low-cost hydrolytic enzymes (obtained by solid-state fermentation of Aspergillus terreus, a fungus isolated from a primary sewage sludge) were added into the feed of the other reactor (Test) for a lipase activity of 24 U/L, considerably reducing the formation of scum. In the Test reactor, the scum showed oil and grease (O&G) concentration between 0.8 and 1.3 g/L and an accumulation rate of 20 to 27 mg O&G/d. In the Control reactor, the scum had values twice as high (1.5–2.5 g/L and 34–51 mg O&G/d, respectively) and there were more operational problems. During the entire period of operation, both reactors presented high chemical oxygen demand removal (>80%), with no loss of effluent quality due to the addition of the enzymes.

The biobed® EGSB (expanded granular sludge bed) system covers shortcomings of the upflow anaerobic sludge blanket reactor in the chemical industry

1997 ◽  
Vol 35 (10) ◽  
pp. 183-188 ◽  
Author(s):  
George R. Zoutberg ◽  
Peter de Been
Keyword(s):  
Waste Water ◽  
Chemical Industry ◽  
Granular Sludge ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Special Configuration ◽  
Anaerobic Reactor ◽  
High Concentrations ◽  
Anaerobic Sludge Blanket ◽  
Brewery Yeast

In this paper a new type of anaerobic reactor is presented. The system has been developed by Biothane Systems and is marketed under the name Biobed® EGSB reactor (Expanded Granular Sludge Bed). In this reactor it is possible to grow and maintain a granular sludge under high liquid (10 m/h) and gas velocities (7 m/h). The most striking feature is the growth of biomass in a granular form, similar to the UASB granules: no carrier material is used. The process is specially suitable to treat waste water that contains compounds that are toxic in high concentrations and that only can be degraded in low concentrations (chemical industry). An example is given for a waste water originating from a chemical factory (Caldic Europoort) in the Netherlands. In this factory formaldehyde is produced from methanol. The waste water is characterised by high concentrations of these compounds (formaldehyde to 10 g/l and methanol to 20 g/l). Due to the special configuration of the anaerobic reactor it is possible to realise a removal efficiency for both compounds of more than 98%. It is also possible to operate the reactor as an ultra high loaded anaerobic reactor (to 30 kg COD/m3.day) for applications in other sectors of industry (e.g. brewery, yeast, sugar, corn ethanol production etc).

A built-in zero valent iron anaerobic reactor to enhance treatment of azo dye wastewater

2011 ◽  
Vol 63 (4) ◽  
pp. 741-746 ◽  
Author(s):  
Yaobin Zhang ◽  
Yanwen Jing ◽  
Xie Quan ◽  
Yiwen Liu ◽  
Pascal Onu
Keyword(s):  
Azo Dye ◽  
Visible Spectrum ◽  
Zero Valent Iron ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Dye Wastewater ◽  
Absorption Bands ◽  
Anaerobic Reactor ◽  
Anaerobic Sludge Blanket

Waste scrap iron was packed into an upflow anaerobic sludge blanket (UASB) reactor to form a zero valent iron (ZVI) - UASB reactor system for treatment of azo dye wastewater. The ZVI acted as a reductant to decrease ORP in the reactor by more than 40 mv and functioned as an acid buffer to increase the pH in the reactor from 5.44 to 6.29, both of which improved the performance of the anaerobic reactor. As a result, the removal of color and COD in this reactor was 91.7% and 53%, respectively, which was significantly higher than that of a reference UASB reactor without ZVI. The UV-visible spectrum demonstrated that absorption bands of the azo dye from the ZVI-UASB reactor were substantially reduced. The ZVI promoted methanogenesis, which was confirmed by an increase in CH4 content in the biogas from 47.9% to 64.8%. The ZVI bed was protected well from rusting, which allowed it to function stably. The effluent could be further purified only by pH adjustment because the Fe2+ released from ZVI served as a flocculent.

Nine years of full-scale anaerobic–aerobic treatment experiences with fermentation industry effluents

1995 ◽  
Vol 32 (12) ◽  
pp. 131-139 ◽  
Author(s):  
T. Çiftçi ◽  
I. Öztürk
Keyword(s):  
Biogas Production ◽  
Energy Requirement ◽  
Treatment Plant ◽  
Full Scale ◽  
Treatment System ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Aerobic Treatment ◽  
Second Stage ◽  
Anaerobic Reactors

This paper presents the results of nine years of experience in design and operating of full-scale anaerobic-aerobic treatment plants in a fermentation industry producing baker's yeast from sugarbeet molasses. The PAKMAYA Izmit Factory has a large two-staged treatment plant since 1986: anaerobic first stage and aerobic second stage. The anaerobic reactors were constructed as Upflow Anaerobic Sludge Blanket Reactors (UASBR) with internal and external sludge recirculation facilities. Average COD removals remain in the range of 75% in the mesophilic anaerobic stage. Average daily biogas production rates are as high as 20,000 m3/day. This treatment plant is one of the largest in the world in terms of biogas production. Similar systems were constructed later in two other factories of the same company (Cumaova-Bolu, Kemalpasa-Izmir). The biogas conversion yield is about 0.65 m3 per kg COD removed. The energy produced from the biogas used in the boiler houses is about 35% of the total energy requirement of the factory. The effluents from the anaerobic first stage are fed to the subsequent aerobic treatment system by mixing with low strength effluents of the factory. The aerobic second stage was designed and operated as an extended aeration activated sludge system. The COD removals of the aerobic stage are averaging at about 60 to 75%. This paper also discusses the operating problems encountered in the various stages of the treatment system and their solutions during the nine years of full-scale operation in three different treatment plants of PAKMAYA.

Pilot plant performance and model calibration of a sequencing batch air-lift reactor

1997 ◽  
Vol 35 (1) ◽  
pp. 121-128
Author(s):  
A. Brenner ◽  
N. Ben-Shushan ◽  
M. H. Siegel ◽  
J. C. Merchuk
Keyword(s):  
Optimization Technique ◽  
Plant Performance ◽  
Upflow Anaerobic Sludge Blanket ◽  
Synthetic Wastewater ◽  
Anaerobic Sludge ◽  
Model Parameters ◽  
Wastewater Treatment Process ◽  
Air Lift Reactor ◽  
Anaerobic Sludge Blanket ◽  
Air Lift

A sequencing batch wastewater treatment process was studied in a 200 L air-lift reactor (ALR), using a synthetic wastewater. A modification of the SBR process was introduced to exploit the ALR's geometric structure using an upflow anaerobic sludge blanket (UASB) mode of feeding. The mean COD removal efficiency of the process was extremely high. A study was made of the change in the filtered COD concentration in the reactor as a function of time during a cycle. A partial reduction in the COD was observed after the UASB Fill stage. Further removal of the residual COD was achieved within a very short time once air was supplied to the system. These phenomena required the inclusion of a biosorption-storage concept in the mathematical description of the system, in order to predict more precisely the COD transformations. The mathematical model parameters were evaluated experimentally and then calibrated with the aid of an optimization technique. Experimental results including COD, MLVSS, DO and OUR changes showed good agreement with model predictions.

Toxicity of Sodium and Potassium Ions on Performance of UASB System

2014 ◽  
Vol 953-954 ◽  
pp. 1105-1108 ◽  
Author(s):  
Seni Karnchanawong ◽  
Kraiwet Kabtum
Keyword(s):  
Biogas Production ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Synthetic Wastewater ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Working Volume ◽  
Anaerobic Sludge Blanket ◽  
Uasb Reactors ◽  
Sodium And Potassium

The objective of this study was to investigate the toxicity of Na+and K+ions on performance of upflow anaerobic sludge blanket (UASB) system. Three laboratory-scale UASB reactors, 15.8 - l working volume, were employed with 1 reactor operated as control. They were loaded at organic loading rate (OLR) of 5 kg COD/(m3-d), treating synthetic wastewater with COD concentration ~ 5000 mg/l. Na+and K+ions were added in the range of 1010 - 7180 and 41 - 7320 mg/l, respectively. No toxicity was observed at influent Na+and K+concentrations up to 3340 and 2750 mg/l, respectively. Slight inhibitions on COD removal were founded at Na+and K+concentrations of 4610 and 3920 mg/l, respectively, but moderate effect on biogas production had occurred. When Na+and K+concentrations were increased to 7180 and 7320 mg/l, respectively, strong inhibitions were observed with COD removal dropped to 45.5 and 48.8 %, respectively. Ratios of biogas productions, as compared to the control reactor, were dropped to 0.31 and 0.32, respectively. Increasing cation concentrations had more detrimental effect on biogas production than COD removal.

scholarly journals A Simple and Low Cost Technique for Determining the Granulometry of Upflow Anaerobic Sludge Blanket Reactor Sludge

1999 ◽  
Vol 40 (8) ◽  
pp. 1-8 ◽  
Author(s):  
A. Laguna ◽  
A. Ouattara ◽  
R. O. Gonzalez ◽  
O. Baron ◽  
G. Famá ◽  
...  
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Tap Water ◽  
Low Cost ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Solid Loss ◽  
Size Profile ◽  
Anaerobic Sludge Blanket

Four techniques (microscope sizing, calculation from settling velocities, image and laser analysis) are available nowadays for determining the particle size distribution of upflow anaerobic sludge blanket (UASB) reactor sludge. These techniques present however the disadvantage of being either tedious, imprecise or expensive and hardly applicable in full scale treatment plants. There was then the need for a simple and low cost technique. In this study, a granulometry procedure based on manual humid sieving was evaluated. It was shown that no solid loss occured during the screening and that the particle size profiles were reproducible when performed with sludge samples of 5, 10, 25 and 150 ml, but not 1 ml. Only the results between 10 and 25 ml were however fully identical. It was shown also that the sieving could be performed on sludge samples stored for as long as 50 days at refrigerator temperature and that tap water could be use for the wash and backwash operations without any impact on the particle size profile. The granulometry obtained by image analysis was not comparable to that given by sieving. Nevertheless, no evidence of granule erosion could be found. In any case, the technique allowed us to follow the evolution of sludge granulometry perfectly over time. As a consequence, the manual humid sieving appears to be an adequate technique for determining the granule size distribution of UASB sludges.

Removal of COD from Piggery Wastewater Using a Lab-Scale UASB Reactor

2012 ◽  
Vol 534 ◽  
pp. 221-224
Author(s):  
Fei Yan ◽  
Jin Long Zuo ◽  
Tian Lei Qiu ◽  
Xu Ming Wang
Keyword(s):  
Granular Sludge ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Synthetic Wastewater ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Volume Loading ◽  
Piggery Wastewater ◽  
Start Up ◽  
Anaerobic Sludge Blanket

It took 55 days to start up a lab-scale upflow anaerobic sludge blanket (UASB) reactor at ambient temperature 27-28 oC by using the synthetic wastewater, and piggery wastewater was used as the influent after the reactor start-up. From day 120 onwards, COD removal efficiency maintained in the range of 85% to 95% with 6.79-9.66 kg COD/ (m3•d) of volume loading, and the effluent COD concentration ranged between 400 mg/L and 600 mg/L. Granular sludge formation was observed in the reactor after 40-day operation, and the sludge diameter reached 2-4 mm in the 120 day-old reactor. The pH changes in the influent had little influence on COD removal from piggery wastewater using the UASB reactor.

Development and Evaluation of a Partitioned Upflow Anaerobic Sludge Blanket (UASB) Reactor for the Treatment of Domestic Sewage from Small Villages

1999 ◽  
Vol 40 (8) ◽  
pp. 107-113 ◽  
Author(s):  
Carlos Augusto L. Chernicharo ◽  
Marcílio dos Reis Cardoso
Keyword(s):  
Rural Areas ◽  
Low Cost ◽  
Sewage Treatment ◽  
Field Evaluation ◽  
Domestic Sewage ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Attractive Alternative ◽  
Improved Performance

This paper presents the development and field evaluation of a partitioned UASB reactor, conceived for the treatment of domestic sewage from small villages and areas with large variation of the daily flowrate. In such situations, conventional single compartment UASB reactors are submitted to very extreme hydraulic conditions, that can disturb the behaviour of the treatment system. In the partitioned reactor, which is constituted of three digestion compartments, three gas separation devices and a single settler compartment, an adequate distribution of the variable incoming wastewater into one, two or three digestion chambers, allows the establishment of more stable up flow velocities and less occurrence of dead zones. As a result, a better contact between substrate and biomass can be achieved and an improved performance of the system can be expected. The partitioned UASB reactor was evaluated during a period of 16 months of continuous operation. The system presented a vary good performance during most of the operational period, showing very high efficiencies when the reactor was operated at a HRT of 7.5 hours. In this phase, the unit presented COD removal efficiencies around 80% and an average SS concentration in the final effluent of 32 mgSS/L. The research is still going on, focussing on the evaluation of the system under higher hydraulic loads and on the assessment of sludge activity and dehydration potential. Due to the operational simplicity and low cost of the system, it is believed that this type of reactor can become a very attractive alternative for domestic sewage treatment in small villages, particularly in Brazil where the number of rural areas with wastewater treatment is negligible.

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