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.

scholarly journals Effects of UV Radiation on Photolyase and Implications with Regards to Photoreactivation following Low- and Medium-Pressure UV Disinfection

2007 ◽  
Vol 74 (1) ◽  
pp. 327-328 ◽  
Author(s):  
Jiangyong Hu ◽  
Puay Hoon Quek
Keyword(s):  
Uv Radiation ◽  
Uv Irradiation ◽  
Flavin Adenine Dinucleotide ◽  
Low Pressure ◽  
Uv Disinfection ◽  
Medium Pressure ◽  
Uv Lamps

ABSTRACT Photolyase activity following exposure to low-pressure (LP) and medium-pressure (MP) UV lamps was evaluated. MP UV irradiation resulted in a greater reduction in photolyase activity than LP UV radiation. The results suggest that oxidation of the flavin adenine dinucleotide in photolyase may have caused the decrease in activity.

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.

Photoreactivation of Escherichia coli following medium-pressure ultraviolet disinfection and its control using chloramination

2006 ◽  
Vol 53 (6) ◽  
pp. 123-129 ◽  
Author(s):  
P.H. Quek ◽  
J.Y. Hu ◽  
X.N. Chu ◽  
Y.Y. Feng ◽  
X.L. Tan
Keyword(s):  
Escherichia Coli ◽  
Uv Disinfection ◽  
Fluorescent Light ◽  
Ultraviolet Disinfection ◽  
Bench Scale ◽  
Medium Pressure ◽  
Entire Duration ◽  
Collimated Beam ◽  
Synthetic Water

Ultraviolet (UV) disinfection is becoming increasingly popular as an alternative disinfection technology to chlorination in recent years. In this study, we investigated the photoreactivation of Escherichia coli following medium-pressure (MP) UV disinfection of synthetic water by a bench-scale collimated beam apparatus. The UV doses ranged from 1.6 –19.7 mWs/cm2 and photoreactivation was investigated for 6 hours under fluorescent light. In addition, chloramination was applied after UV disinfection to investigate its ability to control photoreactivation. It was found that photoreactivation occurred for all UV doses tested and the increase in bacteria numbers ranged from 0.04 to 1.35 log10. However, the degree of photoreactivation decreased with increased UV doses. Chloramination experiments revealed that the addition of 0.5 mg/l of monochloramine resulted in suppression of photoreactivation for 1 hour only. An increased monochloramine dose of 1 mg/l was found to prevent photoreactivation for the entire duration of the experiment. The results of this study have shown that photoreactivation occurs even after MP UV disinfection, although it is of a lesser extent at higher UV doses. This study has also established that secondary chloramination can effectively suppress and eliminate photoreactivation with a chloramine dose of 1 mg/l.

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.

Municipal wastewater treatment in Berlin with deep tanks and flotation for secondary clarification

1996 ◽  
Vol 33 (12) ◽  
pp. 199-210
Author(s):  
R. Gnirss ◽  
A. Peter-Fröhlich ◽  
V. Schmidt
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Energy Requirements ◽  
Municipal Wastewater Treatment ◽  
Space Saving ◽  
Process Energy ◽  
Near Future ◽  
Interesting Alternative ◽  
Pilot Tests

For municipal wastewater treatment, space-saving 10m deep activated sludge tanks are an interesting alternative to conventional tanks of shallow construction. Results from pilot tests in the Berlin-Ruhleben WWTP have shown that the biological P-elimination, nutrification and denitrification processes can be implemented as in shallow tanks. However, the activated sludge did not settle satisfactorily. Flotation was implemented in the process for secondary clarification and in the meanwhile has shown to be advantageous. Tests run over a period of some years with the pilot plant have proven the feasibility of this process. Energy requirements for both systems were found to be approximately the same. A cost estimate based on a preplan revealed a 10% advantage in favour of the 10m WWTP with flotation. For these reasons, one 10m WWTP with flotation for secondary clarification and a capacity of 80,000 m3/d will be built in Berlin in the near future.

Challenges of arsenic removal from municipal wastewater by coagulation with ferric chloride and alum

2020 ◽  
Vol 725 ◽  
pp. 138351 ◽  
Author(s):  
Jie Ge ◽  
Biswarup Guha ◽  
Lee Lippincott ◽  
Stanley Cach ◽  
Jinshan Wei ◽  
...  
Keyword(s):  
Ferric Chloride ◽  
Municipal Wastewater ◽  
Arsenic Removal

Removal of suspended substances by coagulation and foam separation from municipal wastewater

2002 ◽  
Vol 46 (11-12) ◽  
pp. 183-188 ◽  
Author(s):  
Y. Suzuki ◽  
T. Maruyama ◽  
H. Tegane ◽  
T. Goto
Keyword(s):  
Suspended Solids ◽  
Municipal Wastewater ◽  
Treatment Time ◽  
Separation Process ◽  
Foam Separation ◽  
Suspended Substances ◽  
Milk Casein ◽  
Short Time ◽  
Solid Liquid ◽  
Solid Liquid Separation

A new method for solid-liquid separation for wastewater incorporating simple operation and shortened treatment time is necessary for improvement of sewage systems. In this study, removal of suspended solids from municipal wastewater by coagulation and foam separation using coagulant and milk casein was examined. By adding casein before the foam separation process, the removal of suspended substances was dramatically improved. The optimum condition for treating sewage was 20 mg-Fe/L of FeCl3, 3 mg/L of casein, and pH 5.5, which resulted in a removal rates of over 98% for turbidity and SS. A removal of 96-98% was also possible for phosphate and anionic surfactant. When PAC was used, the floc was also efficiently recovered in foam by the addition of casein. It became clear that coagulation and foam separation using casein as the collector is an effective method for removing suspended solids in municipal wastewater in a short time (within 10 min).

The use of antibacterial activity of ZnO nanoparticles in the treatment of municipal wastewater

2014 ◽  
Vol 70 (5) ◽  
pp. 763-770 ◽  
Author(s):  
Fatemeh Elmi ◽  
Heshmatollah Alinezhad ◽  
Zahra Moulana ◽  
Fatemeh Salehian ◽  
Sahar Mohseni Tavakkoli ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Municipal Wastewater ◽  
Sol Gel ◽  
Antibacterial Activities ◽  
Uv Disinfection ◽  
Zno Nps ◽  
Water And Wastewater Treatment ◽  
Complementary Method ◽  
Chlorine Disinfection ◽  
Wastewater Quality

Nanotechnology holds great potential in advanced water and wastewater treatment to improve treatment efficiency. Zinc oxide nanoparticles (ZnO NPs) have received considerable attention due to their unique antibacterial activities toward various microorganisms that are commonly found in the environment. In the present study, ZnO NPs were synthesized through both mechano-chemical and sol–gel methods. The synthesized ZnO NPs were characterized through X-ray diffraction and transmission electron microscopy techniques. Then, their antibacterial activities against separated wastewater bacteria were evaluated by determining the zone inhibitor, the minimum inhibitory concentration, and the minimum bactericidal concentration. The results were compared with those obtained from wastewater after chlorine disinfection and ultraviolet (UV) disinfection. These studies demonstrated that the antibacterial activity of ZnO NPs depends on the type and the strain of bacteria. They have also demonstrated that the activity increases as the concentration of ZnO NPs increases. Overall, the experimental results suggest that ZnO NPs can potentially be an antibacterial reagent to treat wastewater. They can particularly be applied as a complementary method with UV disinfection. Thus, they can be developed as antibacterial agents to improve wastewater quality.

scholarly journals Irrigating Wastewater using RWIS for Treating in Soil-Plant System

2019 ◽  
pp. 31-33
Author(s):  
Dahn Rosenqvist
Keyword(s):  
Municipal Wastewater ◽  
Irrigation System ◽  
Specific Area ◽  
Waste Products ◽  
Plant System ◽  
Set Up ◽  
Controlled Flooding ◽  
Computer Operation ◽  
Natural Purification ◽  
Pilot Tests

In Sweden, large areas of willow plantations designated for energy purposes have been established. Pilot tests, using various waste products from society for fertilisation and/or irrigating purposes, have been carried out at Kagerods wastewater plant since 1992. These tests have clearly shown that recycling of municipal wastewater in Salix plantations, can replace a large part of the conventional wastewater treatment, due to natural purification processes in the soil/plant system. During the last few years, several full-scale treatment plants based on the soil/plant system have been set up. Rosenqvist Mek.Verkstad has developed the irrigation system "RWIS" for distribution of wastewater into the plantation. The system uses a controlled flooding technique, combined with computer operation controlled electric valves placed in the fields. By measuring the flow and having knowledge about the contents of the wastewater, it is possible to have total control over the wastewater that is distributed in a specific area. The irrigation system has to be able to withstand trying conditions, without major maintenance in between harvests.

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