A study on the effects of ozone dosage on dissolved-ozone flotation (DOF) process performance

2015 ◽  
Vol 71 (9) ◽  
pp. 1423-1428 ◽  
Author(s):  
Xin Jin ◽  
Pengkang Jin ◽  
Xiaochang Wang

Dissolved-ozone flotation (DOF) is a tertiary wastewater treatment process, which combines ozonation and flotation. In this paper, a pilot-scale DOF system fed by secondary effluent from a wastewater treatment plant (WWTP) in China was used to study the effect of ozone dosage on the DOF process performance. The results show that an ozone dosage could affect the DOF performance to a large extent in terms of color and organic matter removal as well as disinfection performance. The optimal color and organic matter removal was achieved at an ozone dosage of 0.8 mg/l. For disinfection, significant improvement in performance could be achieved only when the organic matter removal was optimal. The optimal ozone dosage of at least 1.6 mg/l was put forward, in this case, in order to achieve the optimal color, turbidity, organic matter and disinfection performance.

2001 ◽  
Vol 43 (2) ◽  
pp. 91-99 ◽  
Author(s):  
T. Iwane ◽  
T. Urase ◽  
K. Yamamoto

Escherichia coli and coliform group bacteria resistant to seven antibiotics were investigated in the Tama River, a typical urbanized river in Tokyo, Japan, and at a wastewater treatment plant located on the river. The percentages of antibiotic resistance in the wastewater effluent were, in most cases, higher than the percentages in the river water, which were observed increasing downstream. Since the possible increase in the percentages in the river was associated with treated wastewater discharges, it was concluded that the river, which is contaminated by treated wastewater with many kinds of pollutants, is also contaminated with antibiotic resistant coliform group bacteria and E.coli. The percentages of resistant bacteria in the wastewater treatment plant were mostly observed decreasing during the treatment process. It was also demonstrated that the percentages of resistance in raw sewage are significantly higher than those in the river water and that the wastewater treatment process investigated in this study works against most of resistant bacteria in sewage.


2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Benxin Yu ◽  
Dongping Liu ◽  
Jian Wang ◽  
Yingxue Sun

Abstract Background Most particulate organic matter (POM) cannot be directly degraded in the conventional wastewater treatment, which should be transformed into dissolved organic matter (DOM) through a hydrolysis process. However, non-hydrolyzed POM in the biological treatment can limit treated efficiencies for the wastewater treatment plants (WWTPs) facilities. Hence an operational tool is indispensable for insight into removals of DOM and POM factions in the WWTP. In this study, excitation-emission matrix fluorescence spectroscopy (EEM) combined parallel factor analysis (PARAFAC), two-dimensional correlation (2D-COS) and structural equation modeling (SEM) was employed to evaluate removals of DOM and POM in a wastewater treatment plant. Results Four fluorescence components were identified in DOM and POM substances from the WWTP by EEM combined with PARAFAC, i.e., tyrosine-like (TYLF), tryptophan-like (TRLF), microbial byproduct-like (MBLF), and fulvic acid-like (FALF). In A2/O process, the TYLF and TRLF of DOM were removed to a larger extent than those of MBLF and FALF in anaerobic tank, while TYLF and MBLF of POM were removed to a great extent than those of TRLF and FALF in primary sedimentation and aerobic tanks. By the 2D-COS, a decreasing variation order of DOM fractions in the wastewater treatment process was UV-FALF → MBLF2 → Vis-FALF → TRLF → TYLF, while the decreasing order of POM fractions was Vis-FALF → UV-FALF → MBLF2 → TYLF → MBLF1 → TRLF. SEM revealed that TRLF and TYLF of DOM were degraded by anaerobic microorganism, and TRLF could be transformed partially into FALF. However, TRFL and TYLF of POM were discomposed by aerobic microorganism. Conclusions The 2D-COS and SEM can be practicable tools as EEM-PARAFAC for monitoring DOM and POM in the WWTP. The study could present a theoretical support to improving the retrofit of WWTP and formulating emission standards for organic pollutants.


2001 ◽  
Vol 44 (9) ◽  
pp. 189-196 ◽  
Author(s):  
P. Hardy ◽  
J.E. Burgess ◽  
S. Morton ◽  
R.M. Stuetz

Lab-scale tests were used to determine the amount of H2S that can be treated using a range of different activated sludges. Static vessels were used to study the effects of different H2S concentrations (5, 25, 50 and 75 ppm). The data indicated that odour control may be carried out using certain types of sludge, but sludge type, e.g. carbonaceous, nitrifying, with or without coagulant, affects removal efficiency. The presence of the biomass resulted in greater H2S removal than the use of wet scrubbing and the adverse effects on mixed liquor were negligible. A pilot plant was used to study the removal efficiencies of activated sludge diffusion using a typical wastewater treatment plant H2S concentration and investigated the effects that the diffusion of H2S had on the process performance. Results indicated that the levels of H2S produced by other unit processes on a wastewater treatment site (approximately 5 ppm) can be treated using activated sludge diffusion without compromising the performance of the wastewater treatment process. The only effects on the activated sludge plant observed were: (1) nitrification was interrupted briefly as H2S diffusion commenced and (2) the species' diversity in the sludge decreased.


2020 ◽  
Vol 12 (11) ◽  
pp. 4679 ◽  
Author(s):  
Kulyash Meiramkulova ◽  
Antonis A. Zorpas ◽  
Duman Orynbekov ◽  
Michal Zhumagulov ◽  
Gulnur Saspugayeva ◽  
...  

The efficiency of a wastewater treatment process may be affected by several factors including the scale at which the system is operating. This study aimed at investigating the influence of scale on a poultry slaughterhouse wastewater treatment process. The process is comprised of several units including electrolysis, membrane filtration, and ultraviolet irradiation. The results of the industrial-scale wastewater treatment plant of the Izevski poultry farm slaughterhouse in Kazakhstan were compared with those of a lab-scale wastewater treatment process under the same conditions. The traditional and water quality index (WQI) approaches were used to present the results and the drinking water quality standards of Kazakhstan were used as a reference. The industrial and lab-scale plants showed high purification efficiency for most of the studied water quality parameters. The comparative analysis based on the WQI showed that the industrial-scale wastewater treatment plant outperforms the lab-scale wastewater treatment process.


2018 ◽  
Vol 6 (2) ◽  
Author(s):  
Setiyono Setiyono ◽  
Petrus Nugro Rahardjo

Hospital is playing an important role in serving people who need to get health. On the other hand its occurrence causes some problems as well. One of them is the infectious wastewaters which are potential to cause a dangerous effect for human life. A lot of hospitals in Indonesia do not have the proper wastewater treatment plant yet. The local hospital of County Timika has already had a wastewater treatment plant (WWTP), but until now the capacity of the unit can not fulfil the required level of environmental standard yet. One of the problems is the technically improper treatment processes. To solve the problems, the WWTP must be redesigned and modifief by using a combination technique of anaerobik and aerobic biofilter treatment processes.The newly proposed design process of WWTP for the local hospital in TImika has already prepared to be applied. Keywords : Medical Wastewater Treatment Process, anerobic/aerobic biofilter 


2011 ◽  
Vol 183-185 ◽  
pp. 1057-1060
Author(s):  
Li Kun Huang ◽  
Guang Zhi Wang ◽  
Jin Long Zuo

In order to investigate the characteristic of volatile organic compounds (VOCs) from wastewater treatment plant (WWTP), the air and water samples were collected. The air samples were extracted and identified by GC/MS. The atmospheric VOCs species from all WWTP units were tested. It was shown that the main fugitive sources were primary clarifier and the room of sludge dewatering. The numbers were 33 and 30. The total species of VOCs emitted varied with a range of 16 to 33. The relationship between VOCs species and the change of water quality were discussed. The increasing of VOCs species was related with the higher SUVA, and the molecular weight of VOCs species in air sample gradually become lower along the wastewater treatment process. In the wastewater treatment process,the function of microbe did not contribute the whole effort on the removing of organic pollutants. VOCs volatilized from water phase could also reduce organic pollutants in water phase. In the whole WWTP, the main VOCs species were alkyl with small molecular weight, aromatic hydrocarbon material and naphthalene. Halogenated hydrocarbon was detected in primary treatment unit and anoxic tank.


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