Size fractionation of COD in urban wastewater from a combined sewer system

2004 ◽  
Vol 50 (12) ◽  
pp. 79-86 ◽  
Author(s):  
D. Marani ◽  
V. Renzi ◽  
R. Ramadori ◽  
C.M. Braguglia
Keyword(s):  
Large Fraction ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Complete Removal ◽  
Primary Treatment ◽  
Size Fractionation ◽  
Urban Wastewater ◽  
Physical Fractionation ◽  
Coagulation Tests

The objective of this work was to determine the partitioning of the pollutant load in urban wastewater in order to improve the conventional sewage treatment. In addition to settling tests, physical fractionation of COD in the degritted influent of Roma-Nord sewage treatment plant was performed via sequential filtration through sieves and membrane filters of the following pore size: 150-100-50-25-1-0.2 μm, and 100 kD (about 0.02 μm). Biodegradability studies were also performed on the different size fractions. Size fractionation showed that COD in Roma-Nord sewage is predominantly associated with settleable and supracolloidal (> 1 μm) particles, each size range including about 40% of total COD. Biodegradability tests indicated that the large fraction of COD associated with supracolloidal particles, which are not removed in the primary treatment, is characterised by slow degradability. This suggests that removal of these particles prior to biological treatment may greatly improve the overall treatment scheme. Preliminary pilot plant coagulation tests with lime at pH 9 showed that lime-enhanced primary treatment may increase COD removal efficiencies from typical 30-35% up to 65-70%, by inducing almost complete removal of the COD fraction associated with supracolloidal particles.

Characterization of raw sludge, chemically modified sludge and anaerobically digested sludge in Hong Kong

1998 ◽  
Vol 38 (2) ◽  
pp. 25-32 ◽  
Author(s):  
C. W. Chu ◽  
C. S. Poon ◽  
R. Y. H. Cheung
Keyword(s):  
Hong Kong ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Chemical Properties ◽  
Primary Treatment ◽  
Digested Sludge ◽  
Total N ◽  
Chemically Modified ◽  
Anaerobically Digested Sludge

Chemically Enhanced Primary Treatment (CEPT) or Chemically Assisted Primary Sedimentation (CAPS) is being employed at the new sewage work on Stonecutters Island as part of the Strategic Sewage Disposal Scheme (SSDS) in Hong Kong. CAPS involves the use of chemical coagulants (such as lime or ferric chloride) to induce coagulation or flocculation and let these finely-divided particles form large aggregates (floc) so that they can settle out within a reasonable period of time. In this study, five sludge samples collected from different sewage treatment plants in Hong Kong were physically and chemically characterized. They were chemically modified sludge from Stonecutters Island (CAPS) raw sludge from Tai Po and Yuen Long Sewage Treatment Plant (STP) (rTP & rYL) and anaerobically digested sludge from Tai Po and Yuen Long STP (dTP & dYL). It was found that CAPS sludge was better than other 4 sludge samples in terms of settleability and dewaterability. CAPS sludge contained significant higher amounts (p<0.01) of extractable compounds than other sludges (except NO3− for dTP, NH4+ and PO43− for dYL). The concentration of total N and P in CAPS sludge were significantly higher (p<0.01) than other sludges (except dYL). The concentrations of total Cu, Pb, Ni, Cd, Cr and K in the CAPS sludge were also significantly higher (p<0.01) than other sludge samples. Most of the metals (Cr, Pb, Cr and Zn) in CAPS sludge were associated with the organically-bounded phase. It is concluded that there are significant differences in both physical and chemical properties between the chemically modified sludge and biological treated sludges.

scholarly journals Bacterial Load Reduction in Guheswori Sewage Treatment Plant, Kathmandu, Nepal

2019 ◽  
Vol 15 (1) ◽  
pp. 40-44 ◽  
Author(s):  
Bikram Gautam ◽  
Anjita Rajbhanshi ◽  
Rameshwar Adhikari
Keyword(s):  
Bacterial Load ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Primary Treatment ◽  
Plate Count ◽  
Coagulase Negative Staphylococcus ◽  
Load Reduction ◽  
Grab Sampling ◽  
Treated Effluent

Background: Water sources such as lakes, ponds, river etc. have been continuously contaminated by the   micro organisms and chemicals. The former can pose a significant threat to human health. This work aims at detecting the bacterial load before and after the sewage treatment and hence isolating pathogens from the sewage before primary treatment and secondary treated effluent. Methods: Grab sampling (50mL sewage before primary treatment and secondary treated effluent) was performed for 20 days in the Guheswori  sewage treatment plant. The reduction in microbial load was determined through heterotrophic plate count. Pathogens were screened from the effluent obtained from the secondary treatment plant. Results: Bacterial load reduction was found to be about 48.02% on average. The observed bacterial load reduction might have been caused by bacteriophage flocculation and sedimentation. Pathogens isolated from the treated effluent were Escherichia coli, Salmonella Typhi, Enterococcus faecalis, Staphylococcus aureus, Coagulase negative Staphylococcus (CONS), Citrobacter fruendii, Enterobacter aerogenes, Proteus mirabilis, P. vulgaris, Pseudomonas  aeruginosa. Conclusions: It has been found that the sewage treatment plant helps to reduce the bacterial load which is, however, not capable of effluent polishing where all pathogens are killed. 

scholarly journals Microbial air contamination on the premises of the sewage treatment plant in Bydgoszcz (Poland) and antibiotic resistance of Staphylococcus spp.

2017 ◽  
Vol 43 (4) ◽  
pp. 58-65 ◽  
Author(s):  
Marta Małecka-Adamowicz ◽  
Łukasz Kubera ◽  
Wojciech Donderski ◽  
Katarzyna Kolet
Keyword(s):  
Heterotrophic Bacteria ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Antibiotic Sensitivity ◽  
Primary Treatment ◽  
Average Concentration ◽  
Diffusion Method ◽  
Air Contamination ◽  
Staphylococcus Spp

AbstractThe study was aimed at evaluating microbial contamination on the premises of the sewage treatment plant by determining the concentrations of selected groups of airborne microorganisms. Another objective was to determine the antibiotic sensitivity patterns of isolated strains of staphylococci. The research was conducted in a seasonal cycle, by the impaction method using Merck MAS-100 air sampler. Samples were collected at six sites, each representing a different stage of sewage treatment. The susceptibility of isolated staphylococci was assessed with the disc-diffusion method, following the recommendations of the EUCAST. The results indicate that the microbial population in the air of the investigated area was dominated by mold fungi, whose highest average concentration was recorded at site IV located near the final clarifier (7672 CFU•m-3). Heterotrophic bacteria and mannitol-positive staphylococci were the most numerous at locations where sewage undergoes primary treatment. In each subseuqent stage the number of microorganisms emitted into the air from the sewage was lower. Antibiograms show that more than 50% of Staphylococcus spp. exhibited resistance to penicillin and 20% to rifampicin. In addition, 90% of the analyzed strains were sensitive to other antibiotics. The fungal community included the following genera: Cladosporium, Fusarium, Alternaria, Penicillium, Aspergillus, Aureobasidium, and Acremonium.The highest air contamination with all studied groups of microorganisms was recorded at the locations where mechanical sewage treatment was performed. During the subsequent stages lower numbers of heterotrophic bacteria were emitted into the air. The air in the investigated sewage treatment plant did not contain multidrug-resistant staphylococci.

scholarly journals Obtaining filamentous fungi and lipases from sewage treatment plant residue for fat degradation in anaerobic reactors

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5368 ◽  
Author(s):  
Anna Cristina P. Lima ◽  
Magali C. Cammarota ◽  
Melissa L.E. Gutarra
Keyword(s):  
Filamentous Fungi ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Basal Medium ◽  
Primary Treatment ◽  
Lipase Production ◽  
Plant Residue ◽  
Anaerobic Reactors

A residue from the primary treatment of a Wastewater Treatment Plant (WWTP) was used to isolate filamentous fungi with lipase production potential. Two of the 27 isolated fungi presented high hydrolysis index and were selected for lipase production by solid-state fermentation (SSF). The fermentations were conducted at 30 °C for 48 h, with moist air circulation, using 20% (w/w) of the residue mixture with a basal medium (agroindustrial residue—babassu cake), obtaining a solid enzymatic preparation (SEP) with lipase activity of 19 U/g with the fungus identified as Aspergillus terreus. Scum, collected in an anaerobic reactor operating in a WWTP, was hydrolyzed with SEP and subjected to anaerobic biodegradability tests at 30 °C. Different dilutions of crude (Control) or hydrolyzed scum in raw sewage were evaluated. The dilution of 5% (v/v) of hydrolyzed scum in raw sewage proved the most adequate, as it resulted in higher methane yield compared to the raw sewage (196 and 133 mL CH4/g CODadded, respectively), without increasing the chemical oxygen demand (COD) of the treated sewage (138 and 134 mg/L). The enzymatic hydrolysis of the scum, followed by dilution in the influent sewage, is technically feasible and increases methane production in anaerobic reactors.

Rethinking sewage treatment by enhancing primary settling with low-dosage lime

2005 ◽  
Vol 52 (10-11) ◽  
pp. 185-192 ◽  
Author(s):  
R. Ramadori ◽  
D. Marani ◽  
V. Renzi ◽  
R. Passino ◽  
A.C. DiPinto
Keyword(s):  
Sewage Treatment ◽  
Complete Removal ◽  
Primary Treatment ◽  
Treatment Efficiency ◽  
Crossflow Filtration ◽  
Physical Separation ◽  
Size Fractions ◽  
Sludge Digestion ◽  
Coagulation Tests ◽  
Low Dosage

This work presents a thorough fractionation of COD in raw sewage, followed by pilot plant coagulation tests with low-dosage lime (pH 9). Through a physical separation (sieving and crossflow filtration) total COD in the raw sewage was partitioned among eight size fractions in the range of 150–0.02μm. In addition, respirometric tests were performed to measure the biodegradability of the different size fractions. More than 60% of COD was associated with settleable and supracolloidal particles (size >1μm), which are characterised by slow biodegradability. Coagulation with lime increased COD removal efficiencies in the primary treatment from typical 30–35%, up to 65–70%, suggesting that lime may induce the almost complete removal of the slowly settling, slowly biodegradable supracolloidal particles in the primary treatment. On the basis of these results a non-conventional sewage treatment scheme is proposed, considering that there is plenty of space for improving primary treatment efficiency through sewage coagulation. Higher primary treatment efficiency may present several advantages, including lower aeration energy in the subsequent biological unit and higher energy recovery from sludge digestion.

Urban Wastewater Disposal and Eutrophication Risk Assessment in the Coastal Zone

1992 ◽  
Vol 25 (12) ◽  
pp. 77-86 ◽  
Author(s):  
J. F. Guillaud ◽  
A. Aminot ◽  
A. Menesguen
Keyword(s):  
Coastal Zone ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Phosphorus Limitation ◽  
Urban Wastewater ◽  
Wastewater Disposal ◽  
Nutrient Loadings ◽  
Limiting Nutrient

The main objective of this paper is to evaluate the possible relationship between urban wastewater disposal and eutrophication in the coastal zone. Firstly, nutrient loadings are studied in raw and treated sewages coming from physical-chemical and biological wastewater treatment plants. Secondly biological responses of coastal ecosystems to overenrichment are considered in term of macroalgal or phytoplanktonic proliferations. Finally it can be deduced that to assess the risk of eutrophication due to urban wastewater disposal, it is necessary a) to evaluate the form and the respective importance of urban and riverine nutrient loadings into the site, b) to determine the physical sensitivity of the disposal area by evaluating the morphological or hydrodynamical entrapment of water masses, c) to point out possible nitrogen or phosphorus limitation for primary production in a potentially eutrophicated site. All these evaluations may help optimizing a reduction strategy of nutrient coastal discharge by urban wastewater, and finding the limiting nutrient that must be controlled in the sewage treatment plant.

Effects of advanced oxidation processes (AOPs) on the toxicity of a mixture of pharmaceuticals

2004 ◽  
Vol 50 (5) ◽  
pp. 23-28 ◽  
Author(s):  
R. Andreozzi ◽  
L. Campanella ◽  
B. Fraysse ◽  
J. Garric ◽  
A. Gonnella ◽  
...  
Keyword(s):  
Advanced Oxidation Processes ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Mixture Toxicity ◽  
Complete Removal ◽  
Toxicity Tests ◽  
Time Of Application ◽  
Synechococcus Leopoliensis ◽  
Standardized Bioassays

The possibility of applying main AOP techniques, namely ozonation, H2O2/UV photolysis and TiO2 photocatalysis to provide a significant reduction of toxicity of pharmaceutical mixtures has been evaluated. For the preparation of the mixture six pharmaceuticals were chosen among those found at highest concentrations in Sewage Treatment Plant effluents, namely carbamazepine, clofibric acid, diclofenac, sulfamethoxazole, ofloxacin and propranolol. The blue-green alga Synechococcus leopoliensis and the rotifer Brachyonus calyciflorus were utilised to assess the toxicity of the mixtures after AOP treatments. All the toxicity tests were performed using chronic standardized bioassays. The best results were obtained with ozonation. With this type of treatment a complete removal of mixture toxicity on S. leopolensis was obtained even after the shortest time of application (1 min). The ozonation treatment leads also to removal of all the pharmaceutical mixture toxicity on B. calyciflorus, by applying the oxidizing agent for at least for 2 minutes.

scholarly journals Edukacja ekologiczna prowadzona przez Grupową Oczyszczalnię Ścieków ŁódzkiejAglomeracji Miejskiej i jej znaczenie w równoważeniu rozwoju

2019 ◽  
pp. 23-31
Author(s):  
Paweł Dziemdziela
Keyword(s):  
Sustainable Development ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Ecological Education ◽  
Urban Wastewater ◽  
The Impact

The article presents the role of ecological education and its impact on sustainable development on the example of the Group Urban Wastewater Sewage Treatment Plant. The results of research on the impact of ecological education on residents were presented.

scholarly journals Multiple β-Lactam Resistance Gene-Carrying Plasmid Harbored by Klebsiella quasipneumoniae Isolated from Urban Sewage in Japan

mSphere ◽  
2019 ◽  
Vol 4 (5) ◽  
Author(s):  
Yasunori Suzuki ◽  
Miki Ida ◽  
Hiroaki Kubota ◽  
Tsukasa Ariyoshi ◽  
Ko Murakami ◽  
...  
Keyword(s):  
Public Health ◽  
Resistance Genes ◽  
Broad Spectrum ◽  
One Health ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Urban Wastewater ◽  
Content Type ◽  
Broad Spectrum Resistance

ABSTRACT The continuous emergence of carbapenemase-producing Enterobacteriaceae (CPE) presents a great public health challenge. Mitigation of CPE spread in the environment is crucial, particularly from a One Health perspective. Here we describe the isolation of CPE strain SNI47 from influent water of a sewage treatment plant in Japan. SNI47 was identified as Klebsiella quasipneumoniae subsp. quasipneumoniae by phylogenetic analysis and was resistant to β-lactams, including carbapenems. Of four plasmids detected from SNI47, the 185,311-bp IncA/C2 plasmid (pTMSNI47-1), which carried 10 drug resistance genes, including genes for four β-lactamases (blaCTX-M-2, blaDHA-1, blaKHM-1, and blaOXA-10), was transferred to Escherichia coli J53 via conjugation. The MICs of all tested β-lactams for the transconjugant were higher than for the recipient. We constructed recombinant plasmids, into which each β-lactamase gene was inserted, and used them to transform E. coli DH5α cells, demonstrating that KHM-1 enhanced carbapenem resistance. In addition, these β-lactamases were responsible for a wide-spectrum β-lactam resistance acquisition with mutual compensation. KHM-1, recognized as a rare type of metallo-β-lactamase, was detected in a transferable plasmid, from a sewage treatment plant, involved in horizontal gene transfer. The detection of such plasmids raises a health risk alarm for CPE dissemination. IMPORTANCE In our investigation of urban wastewater in Japan, carbapenem-resistant Klebsiella quasipneumoniae subsp. quasipneumoniae was isolated that carried the pTMSNI47-1 plasmid, which carries four β-lactamase genes and has transferability among Enterobacteriaceae. pTMSNI47-1 was found to encode a rarely reported carbapenemase, KHM-1. Cooperative effects of β-lactamases encoded by pTMSNI47-1 appeared to have broad-spectrum resistance to β-lactams. The detection of the KHM-1 gene in urban wastewater suggests that such a rare antimicrobial resistance (AMR) gene can be pooled in the environment, potentially emerging as an AMR determinant in a pathogen. When the number of β-lactamase resistance genes is increased in one plasmid, the transfer of this plasmid can confer broad-spectrum resistance to β-lactams, even if the individual gene confers narrow-spectrum resistance. The present study adds important information about the potential risk of sewage treatment plants as reservoirs and environmental suppliers of AMR genes, contributing to the public health from a One Health perspective.

Behaviour of pharmaceuticals and personal care products in a sewage treatment plant of northwest Spain

2005 ◽  
Vol 52 (8) ◽  
pp. 29-35 ◽  
Author(s):  
M. Carballa ◽  
F. Omil ◽  
J.M. Lema ◽  
M. Llompart ◽  
C. García ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Primary Treatment ◽  
Municipal Sewage ◽  
Conventional Activated Sludge ◽  
Natural Estrogens ◽  
Pre Treatment ◽  
Acidic Compounds

Thirteen pharmaceutical and cosmetic compounds have been surveyed along the different units of a municipal sewage treatment plant (STP) to study their fate across each step and the overall removal efficiency. The STP studied corresponds to a population of approximately 100,000 inhabitants located in Galicia (northwest Spain), including three main sections: pre-treatment (coarse and fine screening, grit and fat removal); primary treatment (sedimentation tanks); and secondary treatment (conventional activated sludge). Among all the substances considered (galaxolide, tonalide, carbamazepine, diazepam, diclofenac, ibuprofen, naproxen, estrone, estradiol, ethinylestradiol, roxitromycin, sulfamethoxazole and iopromide), only significant concentrations were found for two musks (galaxolide and tonalide), two antiphlogistics (ibuprofen and naproxen), two natural estrogens (estrone, estradiol), one antibiotic (sulfamethoxazole) and the X-ray contrast media (iopromide), being the other compounds below the quantification level. In the primary treatment, only the fragrances were partly removed, with efficiencies of 20–50% for galaxolide and tonalide. However, the aerobic treatment caused an important reduction in all compounds detected, between 35 and 75%, with the exception of iopromide. The overall removal efficiency of the STP ranged between 70 and 90% for the fragrances, 45 and 70% for the acidic compounds, around 67% for estradiol and 57% for the antibiotic sulfamethoxazole.

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