scholarly journals Shifts in the Microbial Community of Activated Sludge with Different COD/N Ratios or Dissolved Oxygen Levels in Tibet, China

2019 ◽  
Vol 11 (8) ◽  
pp. 2284 ◽  
Author(s):  
Jin Xu ◽  
Peifang Wang ◽  
Yi Li ◽  
Lihua Niu ◽  
Zhen Xing
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Sewage Treatment ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Operational Taxonomic Unit ◽  
Carbon To Nitrogen Ratio ◽  
Urban Sewage ◽  
Treatment Performance ◽  
Nitrogen Ratio

In this study, we examined the influence of the organic carbon-to-nitrogen ratio (chemical oxygen demand (COD/N)) and dissolved oxygen (DO) levels on the removal efficiency of pollutants and on the change in total microflora in the cyclic activated sludge system (CASS) in the Nyingchi prefecture in Tibet. The results demonstrated that the treatment performance was the best when the COD/N ratio was 7:1 or the DO levels were 2–2.5 mg/L in comparison with four different tested COD/N ratios (4:1, 5:1, 7:1, and 10:1) and DO concentrations (0.5–1, 1–2, 2–2.5, and 2.5–3.5 mg/L). The treatment performance can be explained by the relative operational taxonomic unit richness and evenness of the microbial communities in activated sludge. Evident microbial variance was observed, especially different COD/N ratios and DO concentrations, which were conducive to the disposal of urban sewage in plateaus. The results help to understand sewage treatment under different COD/N ratios or DO concentrations on plateaus. This work provides practical guidance for the operation of any wastewater treatment plant on a plateau.

Evaluating the treatment performance of a full scale Activated Sludge Plant in Islamabad, Pakistan

2012 ◽  
Vol 7 (1) ◽  
Author(s):  
S. S. Fatima ◽  
S. Jamal Khan
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Suspended Solids ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Full Scale ◽  
Operational Parameter ◽  
Mixed Liquor ◽  
Treatment Performance

In this study, the performance of wastewater treatment plant located at sector I-9 Islamabad, Pakistan, was evaluated. This full scale domestic wastewater treatment plant is based on conventional activated sludge process. The parameters which were monitored regularly included total suspended solids (TSS), mixed liquor suspended solids (MLSS), mixed liquor volatile suspended solids (MLVSS), biological oxygen demand (BOD), and chemical oxygen demand (COD). It was found that the biological degradation efficiency of the plant was below the desired levels in terms of COD and BOD. Also the plant operators were not maintaining consistent sludge retention time (SRT). Abrupt discharge of MLSS through the Surplus Activated sludge (SAS) pump was the main reason for the low MLSS in the aeration tank and consequently low treatment performance. In this study the SRT was optimized based on desired MLSS concentration between 3,000–3,500 mg/L and required performance in terms of BOD, COD and TSS. This study revealed that SRT is a very important operational parameter and its knowledge and correct implementation by the plant operators should be mandatory.

scholarly journals Arcobacter cryaerophilusand thermophilic campylobacters in a sewage treatment plant in Italy: two secondary treatments compared

1993 ◽  
Vol 110 (3) ◽  
pp. 633-639 ◽  
Author(s):  
S Stampi ◽  
O Varoli ◽  
F Zanetti ◽  
G De Luca
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Most Probable Number ◽  
Tertiary Treatment ◽  
Probable Number ◽  
Urban Sewage ◽  
Thermophilic Campylobacter ◽  
The Mean

SUMMARYMicroaerophilic organisms were monitored in sewage effluent undergoing two secondary treatments: air and oxygen-activated sludge. The mean numbers ofArcobacter cryaerophilusand thermophilic campylobacters detected in incoming sewage were 5639/100 ml and 1720/100 ml respectively.Secondary treatment in air tanks reduced the population ofA. cryaerophilusby 97.1% and of thermophilic campylobacters by 99.08%, whereas treatment in oxygen tanks reduced the bacteria 97.8% and 99.63% respectively, showing that oxygen-activated sludge treatment was more effective. Subsequent tertiary treatment with 2 p.p.m. chlorine dioxide evidenced the removal ofA. cryaerophilusto 99.9% and eliminated thermophilic campylobacters.Campylobacter jejuniandC. coliconstituted 54.1% and 45.9% of 74 thermophilic campylobacter strains isolated. In air-activated sludge effluentC. jejuniwas found more often, thus appearing more sensitive to oxygen.The most probable number assay used for detection of campylobacters, blood medium for enrichment and blood-free medium for plating, also appeared to be fit forA. cryaerophilus, the high density of which in urban sewage may be due to inflows from slaughterhouses.

scholarly journals Evaluation and Performance of Activated Sludge Hi-Kleen Treatment Plant (ASHTP): A Case Study

2021 ◽  
Vol 11 (2) ◽  
pp. 15-24
Author(s):  
Nur Diana Wakimin ◽  
Juferi Idris ◽  
Lydia Dundun Francis ◽  
Maureen Neging ◽  
Siti Rafiqah Muskil ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Treated Effluent ◽  
Overall Performance ◽  
Removal Efficiencies ◽  
And Performance

Pollutants from sewage wastewater are major concerns due to their environmental effects. Thus, an effective sewage wastewater treatment plant is important to ensure discharged effluent is well treated before it can be released to rivers or water streams. This study aims to evaluate the performance of the Activated Sludge Hi-Kleen Treatment Plant (ASHTP) located at H Block (ASHTP at H Block) and L Block (ASHTP at L Block) in UiTM Sarawak Branch, Samarahan Campus, Sarawak, Malaysia. The evaluation was based on physicochemical and removal efficiency namely pH, temperature, turbidity, chemical oxygen demand (COD), and total suspended solids (TSS) from raw influent and treated effluent. The findings indicated that the overall performance of both ASHTP at H Block and L Block were satisfactory where treated effluent meets the standard discharge limits of Environmental Quality (Sewage) Regulations 2009 (Standard B). For ASHTP at H Block, the removal efficiencies of turbidity, COD, and TSS were found to be 86.00, 13.76, and 88.02% respectively, in which the pH, temperature, turbidity, COD, and TSS of the treated effluent were 7.30, 28.10°C, 10.40 NTU, 14.10 mg/L and 8.90 mg/L respectively. Meanwhile, for ASHTP at L Block, the removal efficiencies of turbidity, COD, and TSS were found to be 43.20, 41.90, and 51.61% respectively, in which the pH, temperature, turbidity, COD, and TSS in the treated effluent were 7.30, 27.90°C, 21.10 NTU, 58.10 mg/L and 18.00 mg/L respectively. Proper maintenance of sewage treatment plant is important to ensure its effectiveness as well as to prolong its lifespan.

Application of biochemical products as a bioremediation technique for domestic sewage treatment plants

2007 ◽  
Vol 56 (7) ◽  
pp. 33-40 ◽  
Author(s):  
Salmiati ◽  
M.R. Salim ◽  
R.Md. Hassan ◽  
K.Y. Tan
Keyword(s):  
Suspended Solids ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Quality Parameters ◽  
Sewage Treatment Plants ◽  
Treatment Performance ◽  
Treatment Processes ◽  
Overall Performance

Biochemical products have been widely used for treatment of various types of wastewater. The treatment processes with the addition of biochemical products are quite attractive because of their simplicity, minimal use of equipment, they are environmentally friendly and are suitable for the removal of organic pollutants. The purpose of these products is to enhance the activities of beneficial microbes in order to improve treatment performance. This study was carried out to determine the potential of applying biochemical products in assisting and improving the performance of sewage treatment plants. In this study, four biochemical products, namely: Zeolite, Bio-C, Eco-B and Was-D, were applied to the sewage treatment plant. Analyses were carried out on several water quality parameters such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), oil & grease (O&G), phosphorus (P), ammoniacal nitrogen (AN) and sludge thickness (ST). From the results obtained, it can be seen that the overall performance of the treatment plant improved with most of the parameters studied were found to fulfill the DOE Standard B requirements. The performance of Bio-C was found to give better results than other products.

A Research on the Activated Sludge Acclimation

2012 ◽  
Vol 610-613 ◽  
pp. 1509-1512
Author(s):  
Xiao Nan Zhang ◽  
Shi Qiang Ding ◽  
Ji Run Xu
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Sewage Treatment ◽  
Influence Factors ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Acclimated Activated Sludge

By a circular operation of anaerobic mixing - aerobic aeration – sediment drain, a sludge with low activation obtained from a common sewage treatment plant is acclimated in laboratory. The acclimation is performed with simulated sewage and composed of three periods. In the every period, the sewage concentration is successively increased, the removal percentage of COD, NH4+-N and TP are measured, when the removal is stable, the period is transformed to next one. The outside and construction characteristics of the activated sludge are observed and the protozoon is examined. Meanwhile, some influence factors such as temperature, dissolved oxygen and pH are analyzed. The experiments show that the acclimated activated sludge is able to remove the COD, NH4+-N and TP effectively under a suitable but easy-to-be obtained conditions.

Feasibility Study on the Concentration of Miscible Liquid in Aeration Tank Used by CAF Process

2012 ◽  
Vol 260-261 ◽  
pp. 754-758
Author(s):  
Xiao Tao Guan ◽  
Feng Ping Hu ◽  
Lin Yuan Wang
Keyword(s):  
Activated Sludge ◽  
Industrial Wastewater ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Aeration Tank ◽  
Low Density ◽  
Sludge Treatment ◽  
Sewage Treatment Plants ◽  
Urban Sewage

The Cavitation Air Flotation (CAF) process has been widely applied to the pretreatment of industrial wastewater and urban sewage. However, it has not been applied in the sludge treatment yet. In this paper, Nanchang Chaoyangzhou Sewage Treatment Plant is taken as the example that the CAF process is introduced to the concentration of miscible liquid in the aeration tank in urban sewage treatment plants. According to the optimization of the sludge conditioning agent and the study on the concentration of the miscible liquid in the aeration tank, it is concluded that CAF can be used to concentrate the leftover activated sludge in urban sewage treatment plant, especially that with low density.

scholarly journals Study on the Operation Effect of Constructed Wetland Project for Tailwater Treatment—An Example from a Sewage Plant in Zhejiang Province

2020 ◽  
Vol 194 ◽  
pp. 04030
Author(s):  
Mengyin Chen ◽  
Weifeng Zeng ◽  
Guan Wang ◽  
Fangchun Lu ◽  
Jinjuan Zhang ◽  
...  
Keyword(s):  
Constructed Wetland ◽  
Removal Rate ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Design Parameters ◽  
Class Iii ◽  
Urban Sewage ◽  
Sewage Plant

The constructed wetland project of tailwater from an urban sewage plant in central Zhejiang was selected to collect water samples in different seasons, and the samples were tested for chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN) and other indicators. The results showed that the operation effect of the constructed wetland project is good when the effluent from the sewage treatment plant meets the Class A discharge standard. Among them, the removal effect of TP was the best, with an average removal rate of 61.52%, reaching the standards of surface water class III and class IV in some tests. Besides, the removal effect of TP was stable and varies little with seasons. The removal rates of COD and TN were relatively low and varied greatly with seasons, which were higher in spring and summer than in autumn and winter, with a negative removal rate of TN in winter. This research provides practical data for optimizing the engineering design parameters and improving the operation management to promote the operation efficiency of the constructed wetland.

scholarly journals Performance evaluation of a large sewage treatment plant in Brazil, consisting of an upflow anaerobic sludge blanket reactor followed by activated sludge

2017 ◽  
Vol 76 (8) ◽  
pp. 2003-2014 ◽  
Author(s):  
Pollyane Diniz Saliba ◽  
Marcos von Sperling
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Domestic Sewage ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Removal Efficiencies ◽  
Anaerobic Sludge Blanket

The objective of this study was to evaluate the behaviour of a system comprising an upflow anaerobic sludge blanket reactor followed by activated sludge to treat domestic sewage. The Betim Central sewage treatment plant, Brazil, was designed to treat a mean influent flow of 514 L/s. The study consisted of statistical treatment of monitoring data from the treatment plant covering a period of 4 years. This work presents the concentrations and removal efficiencies of the main constituents in each stage of the treatment process, and a mass balance of chemical oxygen demand (COD) and nitrogen. The results highlight the good overall performance of the system, with high mean removal efficiencies: BOD (biochemical oxygen demand) (94%), COD (91%), ammonia (72%) and total suspended solids (92%). As expected, this system was not effective for the removal of nutrients, since it was not designed for this purpose. The removal of Escherichia coli (99.83%) was higher than expected. There was no apparent influence of operational and design parameters on the effluent quality in terms of organic matter removal, with the exceptions of the BOD load upstream of the aeration tank and the sludge age in the unit. Results suggest that this system is well suited for the treatment of domestic sewage.

Control of Bulking in an Extended Aeration Sewage Treatment Plant

1972 ◽  
Vol 7 (1) ◽  
pp. 13-20
Author(s):  
D.D.P. Cane ◽  
G.J. Farguhar
Keyword(s):  
Dissolved Oxygen ◽  
Control Measure ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Effective Control ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Mixed Liquor ◽  
Air Supply

Abstract A case of filamentous activated sludge bulking was investigated at an extended aeration plant treating wastes from a highway service centre. The purpose of the study was to find an effective control measure for the bulking and, if possible, to determine the cause of the bulking condition. Experiments were conducted to determine the effects upon bulking of: (a) a controlled copper dosage to the mixed liquor, (b) variations in the organic loading rate, and (c) maintenance of high and low dissolved oxygen concentrations in the mixed liquor. The microorganism responsible for the bulking condition was tentatively identified as Sphaerotilus natans. Extensive growths of these bacteria occurred in the sludge when the mixed liquor dissolved oxygen concentration dropped below 0.5 mg/1. Such dissolved oxygen levels had frequently occurred at this plant due to the use of timed aeration cycles and the use of insufficient air supply during peak loading periods. Variations in organic loading rates were found to have no adverse effect on sludge settleability. When bulking was slight, the condition could be improved by increasing the dissolved oxygen level to 1.5 mg/1, or more. The rate at which the filamentous growths could be eliminated from a highly filamentous sludge by increased aeration was very slow, but could be greatly increased by the simultaneous feeding of copper to the mixed liquor at a dosage rate of 1.0 mg/1, based on the raw sewage flows.

High rate and compact single sludge pre-denitrification process for retrofit

1994 ◽  
Vol 30 (6) ◽  
pp. 31-40 ◽  
Author(s):  
Hiroyshi Emori ◽  
Hiroki Nakamura ◽  
Tatsuo Sumino ◽  
Tadashi Takeshima ◽  
Katsuzo Motegi ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Treatment Plant ◽  
High Rate ◽  
Activated Sludge Process ◽  
Nitrogen And Phosphorus ◽  
Conventional Activated Sludge ◽  
Treatment Techniques ◽  
Conventional Activated Sludge Process ◽  
Denitrification Process

For the sewage treatment plants near rivers and closed water bodies in urbanized areas in Japan and European countries, there is a growing demand for introduction of advanced treatment processes for nitrogen and phosphorus from the viewpoints of water quality conservation and environmental protection. In order to remove nitrogen by the conventional biological treatment techniques, it is necessary to make a substantial expansion of the facility as compared with the conventional activated sludge process. In such urbanized districts, it is difficult to secure a site and much capital is required to expand the existing treatment plant. To solve these problems, a compact single sludge pre-denitrification process using immobilized nitrifiers was developed. Dosing the pellets, which are suitable for nitrifiers growth and physically durable, into the nitrification tank of single sludge pre-denitrification process made it possible to perform simultaneous removal of BOD and nitrogen in a retention time equal to that in the conventional activated sludge process even at the low water temperature of about 10 °C. The 3,000 m3/d full-scale conventional activated sludge plant was retrofitted and has been successfully operated.

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