Treatment of municipal wastewater UASB reactor effluent by unconventional flotation and UV disinfection

2005 ◽  
Vol 52 (1-2) ◽  
pp. 315-322 ◽  
Author(s):  
F. Tessele ◽  
L.O. Monteggia ◽  
J. Rubio
Keyword(s):  
Organic Matter ◽  
Water Reuse ◽  
Suspended Solids ◽  
Municipal Wastewater ◽  
Domestic Sewage ◽  
Uasb Reactor ◽  
Uv Disinfection ◽  
Water Turbidity ◽  
Phosphate Ions ◽  
Cationic Flocculant

Post-treatment of an UASB reactor effluent, fed with domestic sewage, was conducted using two-stage flotation and UV disinfection. Results were compared to those obtained in a parallel stabilisation pond. The first flotation stage employed 5–7.5 mg L−1 cationic flocculant to separate off more than 99% of the suspended solids. Then, phosphate ions were completely recovered using carrier flotation with 5–25 mg L−1 of Fe (FeCl3) at pH 6.3–7.0. This staged flotation led to high recoveries of water and allowed us to separate organic matter and phosphate bearing sludge. The water still contained about 1 × 102 NMP/100 mL total coliforms, which were removed using UV radiation to below detection levels. Final water turbidity was <1.0 NTU, COD <20 mg L−1 O2 and 71 mNm−1, the liquid/air interfacial tension. This flotation-UV flowsheet was found to be more efficient than the treatment in the stabilisation pond and appears to have some potential for water reuse. Results were discussed in terms of the biological, chemical and physicochemical mechanisms involved.

Study on the performance of an up-flow aerated biofilter (UAB) in municipal wastewater treatments

1994 ◽  
Vol 30 (11) ◽  
pp. 25-33 ◽  
Author(s):  
Yoshimasa Watanabe ◽  
Satoshi Okabe ◽  
Tomochika Arata ◽  
Yuji Haruta
Keyword(s):  
Organic Matter ◽  
Suspended Solids ◽  
Municipal Wastewater ◽  
Unique Feature ◽  
Aeration Rate ◽  
Loading Rates ◽  
Hydraulic Loading ◽  
Running Cost ◽  
And Performance ◽  
Activated Sludge Systems

A comprehensive wastewater treatment system that accomplishes oxidation of organic matter, nitrification, and denitrification was developed, and its characteristics and performance were investigated. A municipal wastewater was treated by an up-flow aerated biofilter (UAB), in which biofilms were developed on stainless meshes installed horizontally. This UAB exhibited a great potential ability of oxidation of organic matter, SS stabilization, and nitrification due to a unique aeration mechanism giving high DO concentrations with relatively low aeration rates. Another unique feature of the UAB was that attached biofilms on stainless meshes physically filtered out and/or adsorbed suspended solids in the wastewater in addition to the biological oxidation of organic matter. A stable nitrification could be achieved at HRT=10 hours corresponding to a hydraulic loading of 86 L m−2 d−1 and at a ratio of aeration rate to wastewater flow rate (A/W) of 2, which is considerably low as compared to aeration rates of typical activated sludge systems. This UAB system also could handle relatively high hydraulic loading rates. The UAB used in this study still have enough space to install more stainless meshes so as to reduce hydraulic loading rates resulting in the reduction of HRT and aeration rate, which leads to improvement of the system performance as well as reduction of the running cost.

Enhanced pathogen removal in on-site biofiltration systems over organic filtration materials

2008 ◽  
Vol 3 (2) ◽  
Author(s):  
Marco A. Garzón-Zúñiga ◽  
Ana C. Tomasini-Ortíz ◽  
Gabriela Moeller-Chavez ◽  
Yolanda Hornelas-Uribe ◽  
Gerardo Buelna ◽  
...  
Keyword(s):  
Organic Matter ◽  
Removal Efficiency ◽  
Water Reuse ◽  
Municipal Wastewater ◽  
Natural Fibers ◽  
Aeration Rate ◽  
Treated Effluent ◽  
Low Concentrations ◽  
Colony Forming Units ◽  
Tropical Conditions

Municipal wastewater was treated in 4 biofilters packed with a mix of endemic tropical woodchips and natural fibers to evaluate the removal efficiency of organic matter and pathogen microorganisms under tropical conditions. Biofilters were operated during 400 days, with a hydraulic rate of 0.3 m3/m2.d and an aeration rate of 0.68 m3air/m2 h-1. Raw municipal wastewater presented higher concentrations, of organic matter and pathogens, than those reported for municipal wastewaters in temperate countries. However, pollutants were successfully removed: <98.5% of the organic matter as BOD5 < 99.99% of Faecal Coliforms (FC) and Total Colony Forming Units (TCFU), and < 96.93% Helminth eggs (HE) were removed remaining only very low concentrations in the treated effluent (≤2.5 mg DBO5/L; ≤ 240 FC/100 mL; ≤ 240 TCFU /100 mL and < 1.0 HE/5L). According with Mexican regulations (Nom 001-SEMARNAT, 1996) and with the EPA suggested guidelines for water reuse (U.S. EPA, 1992a) treated effluents with this quality can be safely reused for three main activities: Nonfood crop irrigation, landscape impoundments and for construction activities. The high removal efficiency of TCFU and FC may be related with a predatory activity of testate amoebas which were detected growing into the biofilters and, the most plausible hypothesis concerning HE removal is that they are retained by filtration over the organic materials.

Separation of solids and disinfection for agronomical use of the effluent from a UASB reactor

2013 ◽  
Vol 69 (1) ◽  
pp. 25-30
Author(s):  
G. C. Sundefeld Junior ◽  
R. P. Piveli ◽  
S. A. Cutolo ◽  
S. S. Ferreira Filho ◽  
J. G. Santos
Keyword(s):  
Suspended Solids ◽  
High Rate ◽  
Upflow Anaerobic Sludge Blanket ◽  
World Health ◽  
Uasb Reactor ◽  
Most Probable Number ◽  
Anaerobic Sludge ◽  
Uv Disinfection ◽  
Surface Load ◽  
Probable Number

The present work addresses the preparation of the effluent from a full-scale upflow anaerobic sludge blanket (UASB) reactor for drip irrigation of orange crops. The pilot plant included a lamella plate clarifier followed by a geo-textile blanket filter and a UV disinfection reactor. The clarifier operated with a surface load of 115 m3m−2d−1, whereas the filter operated with 10 m3m−2d−1. The UV reactor was an open-channel type and the effective dose was approximately 2.8 W h m−3. The effluent of the UASB reactor received 0.5 mg L−1 cationic polyelectrolyte before entering the high-rate clarifier. Suspended solids’ concentrations and Escherichia coli and helminth egg's densities were monitored throughout the treatment system for 12 months. Results showed that the total suspended solids concentration in the filter effluent was lower than 7 mg L−1 and helminth density was below 1.0 egg L−1. The UV disinfection demonstrated the ability to produce a final effluent with E. coli density lower than 103MPN/100 mL (MPN: most probable number) during the entire process. Thus, the World Health Organization standards for unrestricted crop use were met. Agronomic interest parameters were controlled and it was possible to identify the important contribution of treated sewage in terms of the main nutrients.

Anaerobic Treatment of Domestic Sewage under Moderate Climatic (Dutch) Conditions Using Upflow Reactors at Increased Superficial Velocities

1992 ◽  
Vol 25 (7) ◽  
pp. 167-178 ◽  
Author(s):  
A. R. M. van der Last ◽  
G. Lettinga
Keyword(s):  
Removal Efficiency ◽  
Suspended Solids ◽  
Granular Sludge ◽  
Weather Conditions ◽  
Anaerobic Treatment ◽  
Domestic Sewage ◽  
Uasb Reactor ◽  
Fluidised Bed ◽  
Methanogenic Activity ◽  
Volumetric Loading

This paper describes experiments with domestic sewage using a 120 litre expanded granular sludge bed (EGSB) reactor and a 205 litre fluidised bed (FB) reactor. Presettled domestic sewage was used in the experiments, because these reactor systems are inadeguate in removing SS. Compared to conventional UASB reactors, the advantage of EGSB systems is the significantly better contact between sludge and wastewater. A batch recirculation system was used to assess the maximum achievable removal of the different COD fractions under EGSB and UASB conditions. The results obtained with the EGSB reactor reveal a removal efficiency of 90% with respect to the maximum obtainable efficiency of the soluble COD fraction under dry weather conditions. This efficiency can be obtained at hydraulic retention times (HRT) exceeding 3 hours. Even at HRT's ranging from 2 - 1.5 hours, still 84% - 77% of the maximum possible removal efficiency as assessed in batch recirculation experiments can be achieved at temperatures exceeding 13°C. The advantage of EGSB systems is the high volumetric loading rate that can be applied while maintaining a high removal of the dissolved COD fraction. Moreover, little if any accumulation of inert suspended solids occurs in the sludge bed. On the other hand, the poor removal of suspended solids can be considered as a disadvantage of these systems in treating domestic sewage. Conventional FB systems using sand as carrier material were shown to have little prospect for treating settled domestic sewage, because hardly any methanogenic activity will develop in such a system. However, it was also found that a very satisfactory guality granular sludge developed on settled sewage when operating FB systems in a mode similar to EGSB systems. This granular sludge appeared to be of a guality egual or even better than that of granular seed sludge, cultivated in a UASB reactor treating papermill wastewater.

Domestic sewage treatment in an upflow anaerobic sludge blanket - sequencing batch reactor system

1996 ◽  
Vol 33 (3) ◽  
pp. 73-84 ◽  
Author(s):  
J. T. de Sousa ◽  
E. Foresti
Keyword(s):  
Organic Matter ◽  
Batch Reactor ◽  
Sewage Treatment ◽  
Domestic Sewage ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Excess Sludge ◽  
Aerobic System ◽  
Anaerobic Sludge Blanket

Domestic sewage treatment in up-flow anaerobic sludge blanket (UASB) reactors has presented significant results in tropical regions. This reactor configuration has proven to be efficient in removing organic matter and total suspended solids as well as in producing smaller amounts of excess sludge than conventional aerobic reactor. On the other hand, its effluent often requires to be post-treated in order to achieve the emission standards. This paper is concerned with the alternative proposed here for treating domestic sewage in a combined anaerobic-aerobic system composed of an UASB reactor followed by sequencing batch aerobic reactors (SBR). In such a system, the UASB reactor removes considerable fraction of the influent organic matter, while the SBRs oxidize part of the remaining organic matter and ammonium nitrogen. A proper system operation would also permit the removal of nutrients (N and P). In order to investigate on the performance of this system for sewage treatment, a bench scale installation fed with synthetic substrate simulating domestic sewage was operated continuously during 38 weeks. The results permit to confirm the hypothesis proposed, since the system has consistently produced high quality effluents (BOD5 and VSS lower than 10 mg.L-1). The results also indicate that such combined anaerobic-aerobic system compete favorably with conventional aerobic systems in three essential cost features: energy consumption, excess sludge production and nutrient removal.

Feasibility Study of Municipal Wastewater Treatment by a Subsurface Infiltration System in Northeast, China

2012 ◽  
Vol 610-613 ◽  
pp. 1774-1777
Author(s):  
Hai Bo Li ◽  
Ying Hua Li ◽  
Xin Wang ◽  
Tie Heng Sun
Keyword(s):  
Surface Water ◽  
Northeast China ◽  
Suspended Solids ◽  
Municipal Wastewater ◽  
Oxygen Demand ◽  
Surface Water Quality ◽  
Ammonia Nitrogen ◽  
Domestic Sewage ◽  
Municipal Wastewater Treatment ◽  
Surface Water Pollution

From October 2009 to September 2010, this study focused on investigation the performance of a subsurface wastewater infiltration (SWI) system in treating domestic sewage, and evaluated the potential of the surface water pollution by using the SWI system. The results showed the removal efficiencies were relatively high: for biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), ammonia nitrogen (NH3-N) and total phosphorus (TP) were 95.0, 89.1, 98.1 87.6 and 98.4%, respectively. Meanwhile, the monitoring of a nearby stream characteristic indicated the SWI system could not decrease the receiving surface water quality.

Sludge accumulation in shallow maturation ponds treating UASB reactor effluent: results after 11 years of operation

2014 ◽  
Vol 70 (2) ◽  
pp. 321-328 ◽  
Author(s):  
Thiago Emanuel Possmoser-Nascimento ◽  
Valéria Antônia Justino Rodrigues ◽  
Marcos von Sperling ◽  
Jean-Luc Vasel
Keyword(s):  
Organic Matter ◽  
Suspended Solids ◽  
Algal Growth ◽  
Oxygen Demand ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Liquid Volume ◽  
Anaerobic Sludge ◽  
Natural Systems ◽  
Sludge Accumulation

Polishing ponds are natural systems used for the post-treatment of upflow anaerobic sludge blanket (UASB) effluents. They are designed as maturation ponds and their main goal is the removal of pathogens and nitrogen and an additional removal of residual organic matter from the UASB reactor. This study aimed to evaluate organic matter and suspended solids removal as well as sludge accumulation in two shallow polishing ponds in series treating sanitary effluent from a UASB reactor with a population equivalent of 200 inhabitants in Brazil, operating since 2002. For this evaluation, long-term monitoring of biochemical oxygen demand and total suspended solids and bathymetric surveys have been undertaken. The ponds showed an irregular distribution of total solids mass in the sludge layer of the two ponds, with mean accumulation values of 0.020 m3 person−1 year−1 and 0.004 m3 person−1 year−1 in Ponds 1 and 2, leading to around 40% and 8% of the liquid volume occupied by the sediments after 11 years of operation. The first pond showed better efficiency in relation to organic matter removal, although its contribution was limited, due to algal growth. No simple input–output mass balance of solids can be applied to the ponds due to algal growth in the liquid phase and sludge digestion in the sludge.

Comparing the effluent organic matter removal of direct NF and powdered activated carbon/NF as high quality pretreatment options for artificial groundwater recharge

2008 ◽  
Vol 57 (6) ◽  
pp. 821-827 ◽  
Author(s):  
C. Kazner ◽  
T. Wintgens ◽  
T. Melin ◽  
S. Baghoth ◽  
S. Sharma ◽  
...  
Keyword(s):  
Organic Matter ◽  
Activated Carbon ◽  
Water Reuse ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Powdered Activated Carbon ◽  
Size Exclusion ◽  
Municipal Wastewater Treatment ◽  
Effluent Organic Matter ◽  
High Quality

Direct nanofiltration and nanofiltration combined with powdered activated carbon known as the PAC/NF process were tested regarding the removal of effluent organic matter for reclamation of tertiary effluent from a municipal wastewater treatment plant. They can be regarded as a promising treatment alternative for high quality water reuse applications, especially for direct injection. The total removal for DOC was above 90% with permeate concentrations below 0.5 mg/l. Size exclusion chromatography and fluorescence EEM proved to trace origin of the organic matter even in low concentration ranges. The type and dosage of adsorbent influences the process performance significantly and allows process optimization.

UV disinfection of wastewater coagulated with ferric chloride: recalcitrance and fouling problems

1998 ◽  
Vol 38 (3) ◽  
pp. 15-23 ◽  
Author(s):  
R. Gehr ◽  
H. Wright
Keyword(s):  
Ferric Chloride ◽  
Suspended Solids ◽  
Municipal Wastewater ◽  
Uv Disinfection ◽  
Target Level ◽  
Medium Pressure ◽  
Cleaning System ◽  
Uv Lamps ◽  
Collimated Beam ◽  
Pilot Tests

Collimated beam and pilot tests using low pressure or medium pressure UV lamps were conducted to assess the disinfection performance of a municipal wastewater which had been pretreated by ferric chloride coagulation followed by sedimentation. The feed to the UV systems contained high levels of Fe (often above 3 mg/l); suspended solids and UV254 transmission values were also not ideal (mean approximately 30 mg/l and 32% respectively). The collimated beam tests indicated that the target level of 2,500 coliform forming units/100 ml often could not be reached, and the pilot tests revealed significant fouling after only a few hours. Thus physicochemical effluents of this nature likely require upstream filtration (or a relaxation of the target level) and a continual, automated cleaning system to ensure that performance levels can be maintained.

UV disinfection of stabilization pond effluent: a feasible alternative for areas with land restriction

2012 ◽  
Vol 65 (2) ◽  
pp. 247-253 ◽  
Author(s):  
C. V. P. Alves ◽  
C. A. L. Chernicharo ◽  
M. von Sperling
Keyword(s):  
Escherichia Coli ◽  
Uv Radiation ◽  
Suspended Solids ◽  
Domestic Wastewater ◽  
Low Pressure ◽  
Uasb Reactor ◽  
Uv Disinfection ◽  
Total Coliforms ◽  
Stabilization Pond ◽  
Feasible Alternative

The purpose of this research was to determine the feasibility of a UV photoreactor for the disinfection of effluent from a polishing pond following a UASB reactor treating domestic wastewater. For this, a 20 mm diameter photoreactor (20.7 litre volume) equipped with four 30 W submerged low-pressure mercury arc lamps was used. Three tests with contact times and doses ranging from 45 to 90 s and from 16.9 to 31.3 mW s cm−2 were carried out. Inactivation of total coliforms and Escherichia coli varied from 2.6 to 3.4 log-units, even with the presence of suspended solids in the range of 87 to 102 mg L−1. These results have shown that UV radiation disinfection of pond effluents can be a feasible alternative in areas with land restriction.

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