scholarly journals The persistence of poliovirus in activated sludge treatment

1977 ◽  
Vol 78 (2) ◽  
pp. 165-173 ◽  
Author(s):  
S. A. Balluz ◽  
H. H. Jones ◽  
M. Butler
Keyword(s):  
Single Dose ◽  
Activated Sludge ◽  
Suspended Solids ◽  
Treatment Plant ◽  
Full Scale ◽  
Sludge Treatment ◽  
Mixed Liquor ◽  
Solid Phases ◽  
Liquid And Solid Phases

SUMMARYA model activated sludge treatment plant was used which was functionally very similar to a full scale plant. It was inoculated with poliovirus either continuously or with a single dose and the amounts of virus in the influent, mixed liquor and effluent were monitored regularly. The distribution of the virus in the liquid and solid phases of the mixed liquor was very unequal with about 85% of the virus associated with the suspended solids fraction. Only small amounts of virus were recovered from the effluent and after inoculation was stopped virus rapidly became indetectable. The efficiency of the plant with regard to removal of virus was closely related to its capacity to remove suspended solids and the adsorption of virus to solids and its inactivation is briefly discussed.

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 The behaviour of f2 coliphage in activated sludge treatment

1978 ◽  
Vol 80 (2) ◽  
pp. 237-242 ◽  
Author(s):  
S. A. Balluz ◽  
M. Butler ◽  
H. H. Jones
Keyword(s):  
Activated Sludge ◽  
Treatment Plant ◽  
Full Scale ◽  
Suitable Model ◽  
Sludge Treatment ◽  
Low Background ◽  
Mixed Liquor

SUMMARYA model activated sludge treatment plant was used which was functionally very similar to a full-scale plant. It was inoculated with f2 coliphage and the titres of virus in the influent, the mixed liquor and the effluent were monitored regularly. The distribution of the virus in the solids and liquid fractions of the mixed liquor was in the ratio of 18:82 and 20–4 % of the influent virus was recovered in the effluent. After inoculation was stopped the titre of virus in the solids fraction of the mixed liquor remained high and unaltered for up to 70 h, whereas the value for effluent reverted to the low background titre originally present. These results are discussed in relation to those reported for poliovirus and it is concluded that f2 coliphage is not a suitable model for studies of the behaviour of human enteroviruses.

Behaviour of Mechanically Blended Return-Sludge in Absence of Substrate

1970 ◽  
Vol 5 (1) ◽  
pp. 34-54
Author(s):  
Shyam D. Bokil ◽  
Jatinder K. Bewtra
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Treatment Plant ◽  
Aeration Rate ◽  
Batch Experiments ◽  
Sludge Treatment ◽  
Waring Blender ◽  
Settling Characteristics

Abstract Nine sets of batch experiments, each of ten to twelve days duration, were conducted in the laboratory on return-sludge samples collected from activated sludge treatment plant at Windsor. The thickened sludge samples were blended daily in a waring blender and were continuously aerated in twelve-litres capacity jars. Parallel runs were made on control sludge samples which were not blended. Amongst the parameters varied were the speed and frequency of blending and the aeration rate. The effects of these variables on progressive bio-degradation of volatile suspended solids and the settling characteristics of the sludge were determined. Blended sludge showed significant improvement in the rate of bio-degradation and its settling characteristics as compared to the control unblended sludge

Methane Emissions from Aerated Zones in a Full-Scale Nitrifying Activated Sludge Treatment Plant

2013 ◽  
Vol 225 (1) ◽  
Author(s):  
Amina Aboobakar ◽  
Mark Jones ◽  
Peter Vale ◽  
Elise Cartmell ◽  
Gabriela Dotro
Keyword(s):  
Activated Sludge ◽  
Treatment Plant ◽  
Methane Emissions ◽  
Full Scale ◽  
Sludge Treatment

Full-scale control of Mycolata foam by FEX-120 addition

2010 ◽  
Vol 61 (10) ◽  
pp. 2443-2450 ◽  
Author(s):  
C. Kragelund ◽  
B. Nilsson ◽  
K. Eskilsson ◽  
A. M. Bøgh ◽  
P. H. Nielsen
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
No Reduction ◽  
Treatment Plant ◽  
Full Scale ◽  
Filamentous Bacteria ◽  
Gram Positive ◽  
Sludge Treatment ◽  
Scale Control

Foaming incidents in activated sludge treatment plants are a worldwide problem and occur on a regular basis in both municipal and industrial activated sludge treatment plants. Foaming is most often caused by excessive growth of filamentous bacteria, especially the gram-positive ones affiliated within the Actinobacteria, e.g. the branched Mycolata or CandidatusMicrothrix parvicella. Previous studies have shown that populations of Microthrix can be controlled by addition of certain polyaluminium compounds, but until now no effective chemicals have been identified to control other important foam formers such as the Mycolata. A new chemical (FilamentEx, FEX-120) was tested in full-scale in a Swedish wastewater treatment plant (WWTP) with immense foaming problems. In total, three different dosing events were carried out for more than 1 year. After only 8–17 weeks in each period, all foam had disappeared, and dosing of FEX-120 was stopped. Another 11 full-scale WWTPs in different countries were treated with FEX-120 because of severe Mycolata foaming on process tanks. In nine out of 11 plants, where the causative organisms were Gordonia or Skermania, a significant reduction of foam up to 100% was observed after treatment for approx. 10 weeks. In two WWTPs with unknown Mycolata organisms, no reduction was observed.

scholarly journals The influence of operating conditions of activated-sludge treatment on the behaviour of f2 coliphage

1979 ◽  
Vol 82 (2) ◽  
pp. 285-291 ◽  
Author(s):  
S. A. Balluz ◽  
M. Butler
Keyword(s):  
High Temperature ◽  
Activated Sludge ◽  
Suspended Solids ◽  
Operating Conditions ◽  
Regression Coefficients ◽  
Sludge Treatment ◽  
Mixed Liquor ◽  
Treatment Conditions ◽  
Solids Concentration ◽  
Flow Through

SUMMARYThe behaviour of f2 coliphage during activated-sludge treatment was influenced by the temperature, flow-through-time, concentration of mixed liquor suspended solids and the virus load.The most sensitive way to detect behavioural changes was to examine the regression coefficients for the rate of uptake or loss of virus by the mixed liquor solids. This type of analysis revealed, for instance, high values when the solids concentration was high and even greater values occured when high inocula were used. At high temperature the rate of loss of virus titre after inoculation had stopped was greater than the rate of uptake of virus during inoculation although in all other conditions uptake occurred at a greater rate than the loss of virus. The coefficients were relatively low when the flow rate was increased, when the temperature was low or when the inoculum was small.The distribution of virus between the solids and liquid fractions of the mixed liquor varied somewhat for all conditions but was notably different when (a) the plant was incubated at 5 °C when there was much less virus in the solids fraction than usual, and (b) when the inoculum was low and a much higher proportion of virus was found in the solids.The efficiency with which virus was removed across the plant was the least-sensitive determinant of viral behaviour and the value was about the same for most treatment conditions. However, low or high inocula did result in some increased or decreased removal of virus, respectively.

scholarly journals Efficiency of the work of almond shells as biological carriers in activated sludge aeration tanks: كفاءة عمل قشور اللوز كحوامل بيولوجية في أحواض التهوية بالحمأة المنشطة

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Raghad Salim Al-Shalabi, Naeima Ajib, Mahmoud Fattamah
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Retention Time ◽  
Suspended Solids ◽  
Hydraulic Retention Time ◽  
Aeration Tank ◽  
Sludge Treatment ◽  
Mixed Liquor ◽  
Conventional Activated Sludge ◽  
Fixed Film

Based on the interest in environmentally friendly materials for wastewater treatment, this research is aimed at evaluating the efficiency of almond shells work as biological carriers in activated sludge aeration tanks, known as the integrated fixed-film activated sludge treatment, a hybrid tank with attached growth and suspended growth is obtained. Almond shells were placed at 7% of the size of the aeration tank throughout the experiment period for about 4 months with a number of indicators such as hydraulic retention time and mixed liquor suspended solids. Two sets of experiments were performed, the first group with a constant hydraulic retention time ( HRT= 4 hours), and mixed liquor suspended solids was changed (500-1000-2000-3000 mg/ L), with the best removal efficiency at MLSS = 2000 mg/ l, by 91.3% and 92.1% for COD and SS respectively. The optimal MLSS concentration was adopted for the second group of experiments where HRT was increased to 5 and 6 hours. As a result, the best chain was found to be MLSS = 2000 mg/ l and HRT = 5 hours, with a removal efficiency of 93.4% and 93.9% for COD and SS respectively. As a result, the rate of return activated sludge was reduced from 100% to 60% and the rate of inflow into the aeration tank was increased due to the reduction HRT from 6 hours to 5 hours compared to conventional activated sludge treatment.

Nitrous oxide emissions and dissolved oxygen profiling in a full-scale nitrifying activated sludge treatment plant

2013 ◽  
Vol 47 (2) ◽  
pp. 524-534 ◽  
Author(s):  
Amina Aboobakar ◽  
Elise Cartmell ◽  
Tom Stephenson ◽  
Mark Jones ◽  
Peter Vale ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Treatment Plant ◽  
Full Scale ◽  
Nitrous Oxide Emissions ◽  
Sludge Treatment

scholarly journals The Shock Effect of Inorganic Suspended Solids in Surface Runoff on Wastewater Treatment Plant Performance

2019 ◽  
Vol 16 (3) ◽  
pp. 453 ◽  
Author(s):  
Li He ◽  
Tao Tan ◽  
Zhixi Gao ◽  
Leilei Fan
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Surface Runoff ◽  
Suspended Solids ◽  
Treatment Plant ◽  
Suspended Solid ◽  
Plant Performance ◽  
Normal Operation ◽  
Mixed Liquor

Previous studies on the water quality of surface runoff often focused on the chemical oxygen demand (COD), nitrogen, phosphorus, and total suspended solid (TSS), but little is known in terms of the inorganic suspended solids (ISS). This research investigated the effects of ISS carried by surface runoff on the treatment efficiency of the pretreatment facilities and the ratio of mixed liquor volatile suspended solid to mixed liquor suspended solid (MLVSS/MLSS) of the activated sludge in a wastewater treatment plant (WWTP) with the anaerobic-anoxic-oxic (AAO) process in Chongqing city, China. The results showed that the surface runoff had a long-lasting impact on the grit removal capacity of the grit chamber, affecting the normal operation after the rainfall. In contrast, the primary sedimentation tank showed strong impact resistance with higher removal rates of COD, TSS, and ISS. Nonetheless, the primary settling tank aggravates the removal of organic carbon in sewage during rainfall, having a negative impact on subsequent biological treatment. The ISS in the surface runoff could increase the sludge concentration and decrease the MLVSS/MLSS ratio. After repeated surface runoff impact, the MLVSS/MLSS ratio in the activated sludge would drop below even 0.3, interrupting the normal operation of WWTP.

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