scholarly journals Prevalence of the stx2 Gene in Coliform Populations from Aquatic Environments

2004 ◽  
Vol 70 (6) ◽  
pp. 3535-3540 ◽  
Author(s):  
Cristina Garc�a-Aljaro ◽  
Maite Muniesa ◽  
Juan Jofre ◽  
Anicet R. Blanch
Keyword(s):  
Fecal Coliform ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Coliform Bacteria ◽  
Municipal Sewage ◽  
Aquatic Environments ◽  
Limited Information ◽  
Human Pathogens ◽  
E Coli

ABSTRACT Shiga toxin-producing Escherichia coli strains are human pathogens linked to hemorrhagic colitis and hemolytic uremic syndrome. The major virulence factors of these strains are Shiga toxins Stx1 and Stx2. The majority of the genes coding for these toxins are borne by bacteriophages. Free Stx2-encoding bacteriophages have been found in aquatic environments, but there is limited information about the lysogenic strains and bacteria present in the environment that are susceptible to phage infection. The aim of this work was to study the prevalence and the distribution of the stx 2 gene in coliform bacteria in sewage samples of different origins. The presence of the stx 2 gene was monitored every 2 weeks over a 1-year period in a municipal sewage treatment plant. A mean value of 102 genes/ml was observed without significant variation during the study period. This concentration was of the same order of magnitude in raw municipal sewage of various origins and in animal wastewater from several slaughterhouses. A total of 138 strains carrying the stx 2 gene were isolated by colony hybridization. This procedure detected approximately 1 gene-carrying colony per 1,000 fecal coliform colonies in municipal sewage and around 1 gene-carrying colony per 100 fecal coliform colonies in animal wastewaters. Most of the isolates belonged to E. coli serotypes other than E. coli O157, suggesting a low prevalence of strains of this serotype carrying the stx 2 gene in the wastewater studied.

The Possible Utilization of Waste Sludge as an Adsorbent for Removal of Organic Vapor

1986 ◽  
Vol 18 (7-8) ◽  
pp. 413-420 ◽  
Author(s):  
P. C. Chiang ◽  
J. H. You
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Municipal Sewage ◽  
Methyl Ethyl ◽  
Organic Vapor ◽  
Waste Sludge ◽  
Catalyst Temperature ◽  
Major Factors ◽  
Municipal Sewage Treatment Plant

In this investigation it was found that the waste sludge obtained from a municipal sewage treatment plant could be reclaimed as an adsorbent for removal of organic vapours, i.e. toluene, methyl-ethyl-ketone and 1-1-2-trichloroethylene, through use of a pyrolysis technique. In order to find the optimum manufacturing process, several tests were performed under various conditions in which the addition of a catalyst, temperature control, and residence time in the furnace, were considered as the three major factors. Both the reclaimed adsorbent and commercially available activated carbon were evaluated to determine their adsorption capacity at various influent concentrations of organic vapours.

scholarly journals The effect of purified sewage discharge from a sewage treatment plant on the physicochemical state of water in the receiver

2016 ◽  
Vol 48 (3) ◽  
pp. 267-284
Author(s):  
Włodzimierz Kanownik ◽  
Agnieszka Policht-Latawiec ◽  
Magdalena Wiśnios
Keyword(s):  
Water Saturation ◽  
Stream Water ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Fold Increase ◽  
Municipal Sewage ◽  
Stream Water Quality ◽  
Sewage Discharge ◽  
Physicochemical State

Abstract The paper presents changes in the contents of physicochemical indices of the Sudół stream water caused by a discharge of purified municipal sewage from a small mechanical-biological treatment plant with throughput of 300 m3·d−1 and a population equivalent (p.e.) – 1,250 people. The discharge of purified sewage caused a worsening of the stream water quality. Most of the studied indices values increased in water below the treatment plant. Almost a 100-fold increase in ammonium nitrogen, 17-fold increase in phosphate concentrations and 12-fold raise in BOD5 concentrations were registered. Due to high values of these indices, the water physicochemical state was below good. Statistical analysis revealed a considerable effect of the purified sewage discharge on the stream water physicochemical state. A statistically significant increase in 10 indices values (BOD5, COD-Mn, EC, TDS, Cl−, Na+, K+, PO43−, N-NH4+ and N-NO2) as well as significant decline in the degree of water saturation with oxygen were noted below the sewage treatment plant. On the other hand, no statistically significant differences between the water indices values were registered between the measurement points localised 150 and 1,000 m below the purified sewage discharge. It evidences a slow process of the stream water self-purification caused by an excessive loading with pollutants originating from the purified sewage discharge.

Assessment of Environmental Quality of Soil Fertilized Grapefruit Trees with Municipal Sewage Sludge

2013 ◽  
Vol 671-674 ◽  
pp. 2736-2741
Author(s):  
Yin An Ming ◽  
Tao Tao
Keyword(s):  
Sewage Sludge ◽  
Environmental Quality ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Land Application ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Limiting Factor

To reuse municipal sewage sludge safely, experiment was carried out on grapefruit trees fertilized with composted sludge from Shiweitou Sewage Treatment Plant in Xiamen City of China, and a method was introduced of how to assess the environmental quality of grapefruit trees soil fertilized with sludge by Set Pair Analysis (SPA) model. The results showed that the soil in the surface layer (0-15cm) and the deeper layer (15-30cm) was less clean, and the environment of soil was not polluted. Thus it was feasible to use sludge as fruit fertilizer. The maximum service life of sludge for continuous land application was estimated by taking Cd as the limiting factor, which would provide scientific guide and technical support for safe land application of sludge.

scholarly journals Is It Possible to Restore a Heavily Polluted, Shallow, Urban Lake?

2020 ◽  
Vol 10 (11) ◽  
pp. 3698
Author(s):  
Jolanta Grochowska ◽  
Renata Augustyniak ◽  
Michał Łopata ◽  
Renata Tandyrak
Keyword(s):  
Bottom Sediment ◽  
Sediment Resuspension ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Water Reservoir ◽  
Dry Weight ◽  
Municipal Sewage ◽  
Lake Basin ◽  
Phosphorus Inactivation

The research was carried out on Karczemne Lake, a water reservoir located in Kartuzy (northern Poland, Pomeranian Lake District). Monitoring of the water and bottom sediment of Karczemne Lake showed a very high level of contamination of the reservoir by a long-term inflow of untreated municipal sewage. The trophic status index of total phosphorus (TP) was unusually high at 101, and the TP content in the bottom sediments—31 mg g−1 (dry weight)—was the highest value recorded worldwide in a lake. Based on the monitoring results, to achieve constant improvement of the water quality, we recommend a completely new, safe and economically justified method of bottom sediment removal and management. A very important aspect of this method is the prevention of uncontrolled sewage discharge back into the lake basin. Removed sediment with interstitial water will be pumped through a pipeline and transported to a sewage treatment plant. In the sediment mining field in which the sludge will be removed, the first phase of phosphorus inactivation will be carried out to chemically precipitate pollutants distributed in the water column as a result of sediment resuspension. After the deepening of the entire lake basin, the method of phosphorus inactivation will be carried out on the entire surface of the lake as the next stage of restoration. A supporting activity will be biomanipulation. Before the restoration is started, the municipal sewerage system will be modernized.

Impact of cold and dilute sewage on pre-fermentation - a case study

2001 ◽  
Vol 43 (11) ◽  
pp. 109-117 ◽  
Author(s):  
D. Bixio ◽  
P. van Hauwermeiren ◽  
C. Thoeye ◽  
P. Ockier
Keyword(s):  
Phosphorus Removal ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
High Rate ◽  
Cold Weather ◽  
Biological Nutrient Removal ◽  
Municipal Sewage ◽  
Biological Phosphorus Removal ◽  
Primary Sludge

The municipal sewage treatment plant (STP) of the city of Ghent (Belgium) has to be retrofitted to a 43%-increase in the nitrogen treatment capacity and to phosphorus removal. Cold weather, dilute sewage and a critical COD over N ratio make the retrofit a challenge for full biological nutrient removal. The potential for fermentation of primary sludge to alter those critical feed sewage characteristics was experimentally evaluated. The idea was that the pinpoint introduction of fermentate could optimise the available reactors by achieving high-rate denitrification and enhanced biological phosphorus removal. The fermentation process was evaluated with a bench scale apparatus. At 20°C (heated process), the hydrolysis yield - expressed in terms of soluble COD - varied from 11% to 24% of the total sludge COD. The fermentation yield expressed in VFA COD varied from 8% to 13% of the total sludge COD. The efficiency of heated fermentation of primary sludge was lower during cold and wet weather, due to the different sewage characteristics, as a result of extended dilution periods and low temperature. The raw sewage, the primary effluent and the fermentate were fractionated according to the requirements for the IAWQ Activated Sludge Model No. 2d. The results clearly show that fermentation in the sewer played an important role and temperature was the driving parameter for the characteristics of the dissolved COD. Instead, the weather flow conditions were the driving parameter for the characteristics of the suspended COD. The results of the detailed fractionation were used as background for process evaluation. The final scenario choice for the retrofit depends on a cost-efficiency calculation.

Thermochemical pretreatment in the anaerobic digestion of waste activated sludge

2002 ◽  
Vol 46 (10) ◽  
pp. 173-179 ◽  
Author(s):  
S. Tanaka ◽  
K. Kamiyama
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Municipal Sewage ◽  
Waste Activated Sludge ◽  
Anaerobic Digesters ◽  
Thermochemical Pretreatment ◽  
Methane Production Rate

Effects of a thermochemical pretreatment on the anaerobic digestion of waste activated sludge (WAS) was investigated by semicontinuously-fed digesters operated at 37¡C. WAS from a return sludge line of a municipal sewage treatment plant was pretreated by autoclaving at 130°C for 5 minutes after adding 0.3g NaOH/g VSS. Solids of WAS were thermochemically solubilized to one half and then 60% or more were in totality solubilized in anaerobic digesters fed with pretreated WAS at 2-8 days of hydraulic retention times (HRT), while only 16-36% were solubilized in digesters fed with raw WAS. The adverse effect of the set temperature (130°C) on the biodegradability of protein was not found. As a result, removal rates of COD in digestion was increased from 38% to 57% at 8 days HRT by the pretreatment. A specific methane production rate in the pretreated process was three times as high as the normal process. The thermochemical pretreatment was found to be very effective to enhance biodegradability as well as solubilization of WAS in anaerobic digestion.

Occurrence and removal of steroidal estrogens in Centre Eastern Tunisia municipal sewage treatment plant

2013 ◽  
Vol 52 (10-12) ◽  
pp. 2330-2339 ◽  
Author(s):  
Dalel Belhaj ◽  
Ikram Jaabiri ◽  
Habib Ayadi ◽  
Monem Kallel ◽  
John L. Zhou
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Municipal Sewage ◽  
Municipal Sewage Treatment Plant

scholarly journals Differences in the ASM model caused by data structure

2018 ◽  
Vol 45 ◽  
pp. 00036
Author(s):  
Zbigniew Kowalewski
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Treated Wastewater ◽  
Municipal Sewage ◽  
Insufficient Amount ◽  
The Usa ◽  
Plant Monitoring ◽  
Model Family

The process of designing and exploiting municipal sewage treatment plants has become much simpler and more efficient thanks to mathematical modeling. The ASM model family is able to simulate the operation of existing or designed objects in a satisfactory manner. The basic problem in Poland is the insufficient amount of data for simulations coming from plant monitoring. It is provided to create unstable model results with difficulties in calibration and validation. The aim of this article is to confirm how the amount of data and its completeness will affect the quality of the simulation performed in the ASM model. The study object is a sewage treatment plant located in Chicago in the USA. It is a sewage treatment plant operating with activated sludge technology, with regular monitoring of the quality of raw and treated wastewater. For modeling, a variant of the ASM model built into the BioWin 5.2 software was used.

Sign in / Sign up

Export Citation Format

Share Document