Modelling the formation of THM (trihalomethanes) during chlorination of treated municipal wastewater

2003 ◽  
Vol 3 (4) ◽  
pp. 277-284 ◽  
Author(s):  
E. Koukouraki ◽  
E. Diamadopoulos
Keyword(s):  
Contact Time ◽  
Municipal Wastewater ◽  
Nitrogen Concentration ◽  
Ammonia Nitrogen ◽  
Secondary Effluent ◽  
Exponential Models ◽  
Ultraviolet Absorbance ◽  
Independent Variables ◽  
Operational Variables ◽  
Doc Concentration

Trihalomethanes (THM) concentrations were determined during chlorination of nitrified and partially nitrified secondary effluents, as well as tertiary effluent. Coagulation tests, with alum doses varying from 0.1 mM to 2.5 mM, were applied prior to chlorination to the nitrified effluent in order to remove organic carbon and thereby control the formation of THM. The results indicated that the operational variables of contact time, ammonia nitrogen concentration, pH and chlorine dose had significant effects on THM formation. In tertiary effluents, as the coagulant dose increased, THM formation decreased with a more pronounced reduction for doses higher than 1.5 mM. Modelling of the THM formation was made by means of empirical exponential models. For the chlorination of the nitrified secondary effluent, contact time, chlorine dose, pH and temperature were the model's independent variables, while for the partially nitrified secondary effluent the equivalent independent variables were the contact time, the chlorine dose and the ammonia nitrogen concentration. Modelling of THM formation during chlorination of tertiary effluent was based on either the DOC concentration or the ultraviolet absorbance, as well as on a combination of both. The three exponential models fit reasonably well the experimental data for all the coagulant doses, except for the 2 and 2.5 mM dose, where the reduction in organic matter was not as high as the equivalent reduction in THM formation. The use of the ultraviolet absorbance alone as an independent variable in the model provided a slightly better simulation of the measured THM concentrations.

Tertiary nitrification in pure oxygen moving bed biofilm reactors

2000 ◽  
Vol 41 (4-5) ◽  
pp. 361-368 ◽  
Author(s):  
L. Bonomo ◽  
G. Pastorelli ◽  
E. Quinto ◽  
G. Rinaldi
Keyword(s):  
Municipal Wastewater ◽  
Treatment Plant ◽  
Ammonia Nitrogen ◽  
Pure Oxygen ◽  
Secondary Effluent ◽  
Municipal Wastewater Treatment ◽  
Typical Application ◽  
Moving Bed ◽  
Biofilm Reactors ◽  
Nitrogen Ratio

Two bench-scale reactors, fed with the secondary effluent of a municipal wastewater treatment plant (WWTP), were used in order to study tertiary nitrification in pure oxygen moving bed biofilm reactors (PO-MBBRs) with patented KMT® media as biofilm carriers. The process allowed to measure very high nitrification rates, both in ammonia limiting conditions (up to 7 gN m−2 d−1; oxygen-to-ammonia nitrogen ratio higher than 3–4 mgO2 (mgN)−1) and in oxygen limiting conditions (up to 8 gN m−2 d−1; oxygen-to-ammonia nitrogen ratio lower than 1–2 mgO2 (mgN)−1). Since the process proved flexible and reliable, it is suitable for full-scale application to municipal WWTPs. Typical application could regard, but is not limited to, tertiary nitrification of secondary effluent from existing high-purity oxygen activated sludge systems designed to achieve only organic carbon removal.

THM formation during chlorination of treated municipal wastewater

2002 ◽  
Vol 2 (3) ◽  
pp. 235-242 ◽  
Author(s):  
E. Koukouraki ◽  
E. Diamadopoulos
Keyword(s):  
Organic Carbon ◽  
Contact Time ◽  
Municipal Wastewater ◽  
Secondary Effluent ◽  
Batch Experiments ◽  
Limited Effect ◽  
Formation Potential ◽  
Coagulation Tests ◽  
Treated Municipal Wastewater

Chlorination batch experiments were conducted in order to estimate the concentration of THM and their formation potential in nitrified and partially nitrified secondary effluent. The role of contact time (up to 2 hours), chlorine dose (3 levels), pH and temperature on the formation of THM was evaluated. THM formation, as measured by individual concentration as well as formation potential, was high for the nitrified secondary effluent, while for the partially nitrified effluent the respective concentrations were low, due to the reaction of chlorine with ammonia to form chloramines. In general, THM concentrations progressively increased as contact time, pH and chlorine dose increased. Increase in temperature (from 15-25°C) showed a rather limited effect. In addition, coagulation tests were applied prior to chlorination of the nitrified effluent for removing organic carbon and thereby controlling the formation of THM. Alum was used as the coagulant in doses varying from 0.1 mM to 2.5 mM. As the coagulant dose increased, the removal of both DOC and absorbance at 254 nm increased, while THM formation decreased. The reduction in THM formation was more pronounced for coagulant doses higher than 1.5 mM.

A study about the use of chemicals in conventional tertiary treatment. Performances comparison of three municipal wastewater treatment plants and pilot plant experiences

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
A. Iborra-Clar ◽  
J.A. Mendoza-Roca ◽  
A. Bes-Pií ◽  
J.J. Morenilla-Martínez ◽  
I. Bernácer-Bonora ◽  
...  
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Pilot Plant ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Secondary Effluent ◽  
Municipal Wastewater Treatment ◽  
Wastewater Reclamation ◽  
Valencian Region ◽  
Municipal Wastewater Treatment Plants

Rainfall diminution in the last years has entailed water scarcity in plenty of European regions, especially in Mediterranean areas. As a consequence, regional water authorities have enhanced wastewater reclamation and reuse. Thus, the implementation of tertiary treatments has become of paramount importance in the municipal wastewater treatment plants (WWTP) of Valencian Region (Spain). Conventional tertiary treatments consist of a physico-chemical treatment of the secondary effluent followed by sand filtration and UV radiation. However, the addition of coagulants and flocculants sometimes does not contribute significantly in the final water quality. In this work, results of 20-months operation of three WWTP in Valencian Region with different tertiary treatments (two without chemicals addition and another with chemicals addition) are discussed. Besides, experiments with a 2 m3/h pilot plant located in the WWTP Quart-Benager in Valencia were performed in order to evaluate with the same secondary effluent the effect of the chemicals addition on the final water quality. Results showed that the addition of chemicals did not improve the final water quality significantly. These results were observed both comparing the three full scale plants and in the pilot plant operation.

Distribution of heterotrophic and autotrophic organisms in a biological aerated filter

2008 ◽  
Vol 3 (3) ◽  
Author(s):  
O. González-Barceló ◽  
S. González-Martínez
Keyword(s):  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Low Cost ◽  
Ammonia Nitrogen ◽  
Organic Load ◽  
Homogeneous Distribution ◽  
Municipal Wastewater Treatment ◽  
Filter Media ◽  
Aerated Filter ◽  
Secondary Settling

Biological aerated filtration is a viable option for small municipal wastewater treatment plants. A low cost filter media was obtained by triturating volcanic rock. An apparent porosity of 46 % and a specific surface area of 395 m2/m3·d were obtained once the filter was packed by using a grain size of 8.2 mm. The performance of the system, operated as a biological filter, was evaluated under an average organic load of 2.6±0.4 kgCODT/m3·d (6.7±1.1 gCODT/m2·d) without primary and secondary settling. The average CODT decreased from 220 mg/l in the influent to 88 mg/l in the effluent and the CODD was decreased from 148 mg/l in the influent to 50 mg/l in the effluent. The filter media, in combination with the biofilm, allowed a 75 % TSS removal. The ammonia nitrogen decreased from 51 mg/l in the influent to 33 mg/l in the effluent. The maximum flux coefficients of 9.3gCODdissolved/m2·d and 2.9gNH4-N/m2·d at the biofilm surface were used to simulate, with the Michaelis-Menten model, the profiles of dissolved COD, ammonium and nitrates through the aerated filter. It was possible to conclude that the backwashing procedure removed the excess biomass and was responsible for a homogeneous distribution of heterotrophic and autotrophic microorganisms along the filter depth.

WASTEWATER DISINFECTION BY UV AT TRANI MUNICIPAL PLANT

1994 ◽  
Vol 30 (4) ◽  
pp. 125-132 ◽  
Author(s):  
D. Carnimeo ◽  
E. Contini ◽  
R. Di Marino ◽  
F. Donadio ◽  
L. Liberti ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Continuous Operation ◽  
Secondary Effluent ◽  
Municipal Wastewater Treatment ◽  
South Italy ◽  
Wastewater Disinfection ◽  
Pilot Investigation ◽  
Effluent Characteristics

The pilot investigation on the use of UV as an alternative disinfectant to NaOCI was started in 1992 at Trani (South Italy) municipal wastewater treatment plant (335 m3/h). The results collected after six months continuous operation enabled us to compare UV and NaOCl disinfection effectiveness on the basis of secondary effluent characteristics, quantify photoreactivation effects, evidence possible DBP formation and assess costs.

Increasing the capacity of an extended nutrient removal plant by using different techniques

1998 ◽  
Vol 37 (9) ◽  
pp. 175-183 ◽  
Author(s):  
B. Andersson ◽  
H. Aspegren ◽  
U. Nyberg ◽  
J. la Cour Jansen ◽  
H. Ødegaard
Keyword(s):  
Nitrogen Concentration ◽  
Treatment Plant ◽  
Appropriate Technology ◽  
Secondary Effluent ◽  
Suggested Approach ◽  
Future Design ◽  
Actual Load ◽  
Full Scale Tests ◽  
Plant Capacity ◽  
Treatment Step

A comprehensive investigation which included full scale tests was initiated towards the late 1980:s with the primary aim to find an appropriate technology for the Klagshamn wastewater treatment plant in Malmö, Sweden. The finally selected strategy enabled that a concentration of less than 8 mg N/l could be reached in the secondary effluent without having to extend either the primary or secondary treatment step at the actual load on the plant. In order to comply with a future stringent phosphorus standard however, a tertiary filtration plant has to be built. In future, it has to be anticipated that the load on the plant may be doubled due to the fact that a bridge between Malmö and Copenhagen is being built. As a consequence, it was important to continue the upgrading work by estimating the ultimate plant capacity and to look for measures to increase the capacity if necessary. By optimising the plant operation, it seems possible to reach an effluent nitrogen concentration of less than 12 mg/l at a load corresponding to the future design load. The suggested approach implies that the plant has to be operated on the margin and as a consequence the possibility to include a denitrification step as part of the filtration plant was also investigated. As a result, it was decided to build a separate denitrification step at the same time as the filtration plant was built.

scholarly journals Oxidation of Citalopram with Sodium Hypochlorite and Chlorine Dioxide: Influencing Factors and NDMA Formation Kinetics

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3065
Author(s):  
Juan Lv ◽  
Yan Wang ◽  
Na Li
Keyword(s):  
Sodium Hypochlorite ◽  
Chlorine Dioxide ◽  
Wastewater Treatment Plants ◽  
Ph Value ◽  
High Reactivity ◽  
Secondary Effluent ◽  
Water Matrix ◽  
Formation Kinetics ◽  
Operational Variables ◽  
Two Stages

The highly prescribed antidepressant, citalopram, as one of newly emerging pollutants, has been frequently detected in the aquatic environment. Citalopram oxidation was examined during sodium hypochlorite (NaOCl) and chlorine dioxide (ClO2) chlorination processes since conventional wastewater treatment plants cannot remove citalopram effectively. Citalopram has been demonstrated to form N-nitrosodimethylamine (NDMA) during chlorination in our previous study. Further investigation on NDMA formation kinetics was conducted in the present study. Influences of operational variables (disinfectant dose, pH value) and water matrix on citalopram degradation, as well as NDMA generation, were evaluated. The results indicated high reactivity of citalopram with NaOCl and ClO2. NDMA formation included two stages during CIT oxidation, which were linear related with reaction time. NaOCl was more beneficial to remove CIT, but it caused more NDMA formation. Increasing disinfectant dosage promoted citalopram removal and NDMA formation. However, no consistent correlation was found between citalopram removal and pH. Contrary to the situation of citalopram removal, NDMA generation was enhanced when citalopram was present in actual water matrices, especially in secondary effluent. DMA, as an intermediate of citalopram chlorination, contributed to NDMA formation, but not the only way.

scholarly journals Occurrence of SARS-CoV-2 RNA in Six Municipal Wastewater Treatment Plants at the Early Stage of COVID-19 Pandemic in The United States

Pathogens ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 798
Author(s):  
Samendra P. Sherchan ◽  
Shalina Shahin ◽  
Jeenal Patel ◽  
Lauren M. Ward ◽  
Sarmila Tandukar ◽  
...  
Keyword(s):  
United States ◽  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Quantitative Polymerase Chain Reaction ◽  
The United States ◽  
Secondary Effluent ◽  
Untreated Wastewater ◽  
Treatment Processes ◽  
Wastewater Samples

In this study, we investigated the occurrence of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) RNA in primary influent (n = 42), secondary effluent (n = 24) and tertiary treated effluent (n = 34) collected from six wastewater treatment plants (WWTPs A–F) in Virginia (WWTP A), Florida (WWTPs B, C, and D), and Georgia (WWTPs E and F) in the United States during April–July 2020. Of the 100 wastewater samples analyzed, eight (19%) untreated wastewater samples collected from the primary influents contained SARS-CoV-2 RNA as measured by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) assays. SARS-CoV-2 RNA were detected in influent wastewater samples collected from WWTP A (Virginia), WWTPs E and F (Georgia) and WWTP D (Florida). Secondary and tertiary effluent samples were not positive for SARS-CoV-2 RNA indicating the treatment processes in these WWTPs potentially removed SARS-CoV-2 RNA during the secondary and tertiary treatment processes. However, further studies are needed to understand the log removal values (LRVs) and transmission risks of SARS-CoV-2 RNA through analyzing wastewater samples from a wider range of WWTPs.

Enhanced Performance of Ultrafiltration Membrane with Powdered Zeolite Addition for Secondary Effluent Treatment

2013 ◽  
Vol 838-841 ◽  
pp. 2712-2716
Author(s):  
Yong Tu ◽  
Yong Gang Bai ◽  
Yong Chen ◽  
Wei Jing Liu ◽  
Jun Xu ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Fluorescence Spectra ◽  
Municipal Wastewater ◽  
Three Dimensional ◽  
Treatment Plant ◽  
Ultrafiltration Membrane ◽  
Effluent Treatment ◽  
Secondary Effluent ◽  
Municipal Wastewater Treatment ◽  
Sem Images

The research on ultrafiltration membrane assisted by powdered zeolite for the treatment of secondary effluent from a municipal wastewater treatment plant was studied. The results show that membrane fouling rate is reduced by pre-coating the ultrafiltration membrane with powdered zeolite, and the treatment performance of secondary effluent is enhanced. UV-vis, three-dimensional excitation emission matrix (3D-EEM) fluorescence spectra and scanning electron microscopy (SEM) images for ultrafiltration were also discussed.

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