Comparison of UV and chlorine inactivation of particle and non-particle associated coliform

2002 ◽  
Vol 2 (5-6) ◽  
pp. 403-410 ◽  
Author(s):  
B. Örmeci ◽  
K.G. Linden

Bacteria associated with particles may be sheltered from chlorine and ultraviolet (UV) disinfection. The objective of this study was to compare the disinfection effectiveness of UV irradiation and free chlorine for naturally occurring particle-associated coliform (PAC) and non-particle associated coliform (NPAC) in wastewater using a single wastewater source, under identical laboratory protocols. Samples containing NPAC were obtained using three different methods: EGTA extraction, filtration, and blending followed by filtration. Unaltered wastewater was used for samples containing PAC. Wastewater samples were inactivated with UV irradiation at doses between 0-100 mJ/cm2, and with chlorine at CT values between 0-525 mg min/L. The dose-survival relationships and inactivation rates between PAC, NPAC, and chlorine and UV irradiation were then compared. As expected, both UV and chlorine were effective for inactivation of NPAC. However, under prolonged contact times, chlorine appears to be more effective for inactivation of PAC than UV irradiation. Contact time appears to be the most important factor in determining the effectiveness of chlorine disinfection of PAC, and chlorine CT alone was not a good indicator of disinfection effectiveness in wastewater. PAC was found to survive at UV and chlorine disinfection doses typically applied in a wastewater treatment plant.

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1339
Author(s):  
Javier Bayo ◽  
Sonia Olmos ◽  
Joaquín López-Castellanos

This study investigates the removal of microplastics from wastewater in an urban wastewater treatment plant located in Southeast Spain, including an oxidation ditch, rapid sand filtration, and ultraviolet disinfection. A total of 146.73 L of wastewater samples from influent and effluent were processed, following a density separation methodology, visual classification under a stereomicroscope, and FTIR analysis for polymer identification. Microplastics proved to be 72.41% of total microparticles collected, with a global removal rate of 64.26% after the tertiary treatment and within the average retention for European WWTPs. Three different shapes were identified: i.e., microfiber (79.65%), film (11.26%), and fragment (9.09%), without the identification of microbeads despite the proximity to a plastic compounding factory. Fibers were less efficiently removed (56.16%) than particulate microplastics (90.03%), suggesting that tertiary treatments clearly discriminate between forms, and reporting a daily emission of 1.6 × 107 microplastics to the environment. Year variability in microplastic burden was cushioned at the effluent, reporting a stable performance of the sewage plant. Eight different polymer families were identified, LDPE film being the most abundant form, with 10 different colors and sizes mainly between 1–2 mm. Future efforts should be dedicated to source control, plastic waste management, improvement of legislation, and specific microplastic-targeted treatment units, especially for microfiber removal.


2012 ◽  
Vol 11 ◽  
pp. 25-28
Author(s):  
Arshad Ali ◽  
Muhammad Jawed Iqbal

The decline in the availability and alarming pollution of the existing water resources is the major environmental problem of third-world countries. The main reason of water pollution is the disposal of untreated industrial effl uents. This study was designed to evaluate the pollution load caused by a paper mill, and to propose a wastewater treatment plant design, based on the analyses of wastewater samples. The wastewater samples were collected from the local paper mill for a period of more than four months on a regular basis. The pH, temperature, color, TSS, TDS, BOD, COD and AOX were measured as, 8.1, 23°C, 2,431 PtCo unit, 956 mg/L, 3,046 mg/L, 1,582 mg/L, 2,492 mg/L and 19.81 mg/L, respectively. Based on the data obtained, the wastewater treatment plant consisting of a screening chamber, primary sedimentation tank and a UASB reactor was designed. It was concluded that the treatment effi ciency of more than 75% removal of BOD and COD concentrations could be accomplished. The treatment plant will also be able to produce 2,200 m3/day of biogas.DOI: http://dx.doi.org/10.3126/hn.v11i0.7157 Hydro Nepal Vol.11 2011 pp.25-28


Author(s):  
Jiawei Tang ◽  
Yu Liu ◽  
Peidong Su ◽  
Jingwei Quan ◽  
Yufeng Hu ◽  
...  

Abstract This study investigated the removal of chemical oxygen demand (COD), NH4-N, and perfluorinated compounds (PFCs) in the effluent from a wastewater treatment plant (WWTP) using ZnO coated activated carbon (ZnO/AC). Results suggested that the optimal dosage of the ZnO/AC was 0.8 g/L within 240 min of contact time, at which the maximum removal efficiency of COD was approximately 86.8%, while the removal efficiencies of PFOA and PFOS reached 86.5% and 82.1%. In comparison, the removal efficiencies of NH4-N, PFBA, and PFBS were lower, at approximately 47.9%, 44.0%, and 55.4%, respectively. In addition, COD was preferentially adsorbed before PFCs and NH4-N, when the contact time ranged from 0 to 180 min, and the order of PFCs removal showed a positive correlation with C-F chain length. The kinetic study revealed that the removal of COD, NH4-N, and PFCs could be better depicted and predicted by the Lagergren quasi-second order dynamic model with high correlation coefficients, which involved liquid membrane diffusion, intraparticle diffusion, and photocatalytic reactions. The saturated ZnO/AC was finally regenerated using ultrasound for 3 h and retained excellent performance, which proved it could be considered as an effective and alternative technology.


2021 ◽  
Author(s):  
Kevin Calci ◽  
Kevin Calci

This method was developed at the FDA’s Center for Food Safety and Applied Nutrition for GenomeTrakr’s pandemic response project, monitoring SARS-CoV-2 variants in wastewater. Protocols developed for this project cover wastewater collection, concentration, RNA extraction, RT-qPCR detection, library prep, genome sequencing, quality control checks, and data submission to NCBI. This method describes the collection and transport of raw wastewater samples from a wastewater treatment plant.


2016 ◽  
Vol 73 (7) ◽  
pp. 1719-1727 ◽  
Author(s):  
M. F. Mohd Amin ◽  
S. G. J. Heijman ◽  
L. C. Rietveld

In this study, a new, more effective and cost-effective treatment alternative is investigated for the removal of pharmaceuticals from wastewater treatment plant effluent (WWTP-eff). The potential of combining clay with biodegradable polymeric flocculants is further highlighted. Flocculation is viewed as the best method to get the optimum outcome from clay. In addition, flocculation with cationic starch increases the biodegradability and cost of the treatment. Clay is naturally abundantly available and relatively inexpensive compared to conventional adsorbents. Experimental studies were carried out with existing naturally occurring pharmaceutical concentrations found and measured in WWTP-eff with atrazine spiking for comparison between the demineralised water and WWTP-eff matrix. Around 70% of the total measured pharmaceutical compounds were removable by the clay–starch combination. The effect of clay with and without starch addition was also highlighted.


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Kefa K. Onchoke ◽  
Salomey A. Sasu

The concentration of hexavalent chromium (Cr(VI)), a toxic environmental pollutant and carcinogen, was determined in samples collected from Nacogdoches Wastewater Treatment Plant (NWWTP) using ion chromatography and UV-visible spectrophotometry (IC, UV-Vis). On reaction with 1,5-diphenylcarbazide (DPC) Cr+6 forms a 1,5-diphenylcarbazide-Cr(VI) complex, which is then analyzed at 530 nm and 540 nm, respectively. Via ion chromatography Cr(VI) concentrations were in the range of 0.00190±0.0020 and 0.0010±0.0006 ppm at the influent and effluent, respectively. With the use of standard addition wastewater samples were spiked with a 0.5 ppm Cr(VI) standard of various amounts and subsequently analyzed with UV-Vis spectrophotometry. The spiked concentrations gave Cr(VI) concentrations in the range of 0.0090±0.0060 ppm and 0.0040±0.0061 ppm at the influent and influent wastewater, respectively. The determined Cr(VI) concentrations through the ion chromatography and UV-Vis spectrophotometry are below the maximum USEPA contaminant concentration of 0.1 ppm. From the analysis, the NWWTP efficiently removes Cr(VI) before discharge into the environment through La Nana Creek. The removal efficiency for Cr(VI) was determined to be ≥92.8% along the wastewater treatment stages from the influent (aeration stage) to the effluent stages prior to discharge into the La Nana Creek.


Intervirology ◽  
2021 ◽  
pp. 1-6
Author(s):  
Ousmane Kebe ◽  
Maria-Dolores Fernandez-Garcia ◽  
Amary Fall ◽  
Hamet Dia ◽  
Maxime Bidalot ◽  
...  

<i>Aichi virus 1</i> (AiV-1) has been proposed as a causative agent of human gastroenteritis. In this study, raw, decanted, and treated wastewater samples from a wastewater treatment plant in an urban area of Dakar, Senegal, were collected. AiV-1 was detected in raw (70%, 14/20), decanted (68.4%, 13/19), and treated (59.3%, 16/27) samples, revealing a noticeable resistance of AiV-1 to chlorine-based treatment. Phylogenetic analysis revealed that all sequences clustered within genotype B. Our study presents the first report on the detection of AiV-1 in the environment of Dakar and constitutes indirect evidence of virus circulation in the population.


2013 ◽  
Vol 319 ◽  
pp. 182-187
Author(s):  
Viecelli Nathália Cristine ◽  
Cardoso Eduardo Müller ◽  
Lovatel Eduardo Ribeiro ◽  
Nascimento Filho ◽  
Irajá Do

This study investigated the occurrence of Bisphenol A (BPA), di-n-butyl phthalate (DBP), and di(2-ethylhexyl)phthalate (DEHP) in the wastewater treatment plant of the University of Caxias do Sul (WWTP-UCS). The wastewater samples from the inflow and outflow points were submitted to Liquid-Liquid Extraction (LLE). The organic extracts were analyzed by Gas Chromatography with Flame Ionization Detection (GC-FID). The average concentrations at the outflow points were 3.17, 5.83 and 2.10 µg/mL, for BPA, DBP and DEHP, respectively. These high target compound contents at the outflow point may be due to the low removal of suspended solids from the raw samples.


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