Behavior of Musty Odorous Compounds during the Process of Water Treatment

1988 ◽  
Vol 20 (8-9) ◽  
pp. 261-267 ◽  
Author(s):  
K. Ashitani ◽  
Y. Hishida ◽  
K. Fujiwara
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Pilot Plant ◽  
Residual Chlorine ◽  
Raw Water ◽  
Undetectable Level ◽  
Sand Filter ◽  
Musty Odor ◽  
Free Residual Chlorine ◽  
Suspended Form

Geosmin and 2-methylisoborneol (MIB) are two of the causative compounds responsible for the musty odor problem in drinking water. Geosmin and MIB in raw water were present both in solution and in a suspended form mostly associated with the host cyanobacteria. Geosmin and MIB in suspended form were well removed by coagulation and sedimentation alone. Geosmin present in solution could be removed almost to an undetectable level in the rapid sand filter of the pilot plant where no pre-chlorination was practiced. Breakpoint pre-chlorination, however, forced geosmin and MIB present inside of the host algae to leak into the water. The concentration of MIB decreased in a sedimentation basin during the daytime, but not at night in the plant practicing breakpoint pre-chlorination. Geosmin and MIB were both decomposed under sunlight in the presence of free residual chlorine.

scholarly journals Simulation of NOM events in pilot plant evaluation of DAF/Ozone/BAC for drinking water treatment

2017 ◽  
Vol 17 (6) ◽  
pp. 1793-1800
Author(s):  
Y. Yan ◽  
M. Carter ◽  
A. Mercer
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Pilot Plant ◽  
Drinking Water Treatment ◽  
Natural Occurrence ◽  
Raw Water ◽  
Humic Materials ◽  
Pilot Investigation ◽  
Brewing Method ◽  
Plant Evaluation

Abstract Pilot plant testing is invaluable for ascertaining the robustness of water treatment processes against raw water quality events such as turbidity and colour spikes, whether it be for stress testing of an existing process or designing of a new process. Unfortunately, the natural occurrence of such events (particularly colour) can be difficult to predict and commercial humic materials generally fail to closely match the indigenous natural organic matter (NOM) present in the raw water. Therefore, it is highly desirable to be able to simulate NOM event conditions. This paper describes a simple brewing method that we developed and used in our recent pilot plant evaluation of a proposed DAF/Ozone/BAC process for drinking water treatment. Using this method we successfully prepared, by using fallen leaves etc. collected from the local catchment area, large quantities of a concentrated NOM stock solution with its specific ultraviolet absorbance (SUVA), when diluted, very close to the median SUVA of historical NOM events. The brewed solution showed broadly similar NOM characteristics to those of the raw water encountered during the pilot investigation period in terms of molecular weight distribution and fractionation. The coagulation behaviour was also examined for the spiked and non-spiked raw water.

scholarly journals Investigating the occurrence of algae in the drinking water supply system of Harare, Zimbabwe

2020 ◽  
Vol 10 (2) ◽  
pp. 179-190
Author(s):  
Pardon Dandadzi ◽  
Zvikomborero Hoko ◽  
Tamuka Nhiwatiwa
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Treatment ◽  
Water Supply ◽  
Distribution System ◽  
Quality Parameters ◽  
Supply System ◽  
Water Quality Parameters ◽  
Residual Chlorine ◽  
Raw Water

Abstract This study assessed the quality of drinking water in the water supply system for the City of Harare (Zimbabwe) by investigating the occurrence of algae and other water quality parameters that affect its growth. At Morton Jaffray Water Treatment Works (MJWTWs), samples were collected from the raw water inlet and treated water outlet points. In the distribution system, samples were collected from selected sites and grouped into four zones (1, 2, 3 and 4). The algal taxonomic groups that were found in both raw and treated water comprised of Cyanophyceae, Chlorophyceae, Bacillariophyceae, Euglenophyceae and Dinophyceae. It was found out that Microcystis aeruginosa followed by Anabaena were the most abundant species in both raw water and in the distribution system. All measured water quality parameters were within the Standards Association of Zimbabwe and WHO guideline values except for chlorine which had an average residual chlorine concentration that was lower than the WHO recommended lower value of 0.2 mg/L in parts of Zone 2. Morton Jaffray Water Treatment Works does not completely remove algae, and there is a carry-over of algae into the distribution system. Boosting of chlorine is recommended for Zone 2 that had residual chlorine less than the WHO minimum threshold of 0.2 mg/L.

Isolation of viruses from drinking water at the Pont-Viau water treatment plant

1981 ◽  
Vol 27 (4) ◽  
pp. 417-420 ◽  
Author(s):  
Pierre Payment
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Polluted Water ◽  
Residual Chlorine ◽  
Raw Water ◽  
Poliovirus Type ◽  
Treatment Processes

Viruses were isolated from every sample of raw (100 L) and treated (1000 L) water collected at a water treatment plant drawing sewage-contaminated river water. Few plaque-forming isolates were found but cytopathogenic viruses were isolated as frequently in drinking water as in raw water. In drinking water some samples contained more than 1 cytopathogenic unit per litre, but most contained 1–10/100 L. These viruses had not been inactivated or removed by prechlorination, flocculation, filtration, ozonation, and postchlorination. There were no coliforms present and a residual chlorine level had been maintained. Poliovirus type 1 was a frequent isolate but many isolates were nonpoliovirus. The presence of these viruses in drinking water raises questions about the efficacy of some water treatment processes to remove viruses from polluted water.

scholarly journals Performance of rapid sand filter – single media to remove microplastics

2021 ◽  
Author(s):  
Emenda Sembiring ◽  
Mutiara Fajar ◽  
Marisa Handajani
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Removal Efficiency ◽  
Alternative Treatment ◽  
Treatment Process ◽  
Drinking Water Treatment ◽  
Raw Water ◽  
Sand Filter ◽  
Water Treatment Process ◽  
Water Treatments

Abstract Microplastics (MPs) have been detected in drinking water and raw water sources. Therefore, it is important to know the performance of drinking water treatment process. Rapid sand filter (RSF)is one of the water treatments that can be an alternative treatment in removing MPs after several configuration processes (pre-sedimentation, coagulation-flocculation, and sedimentation). This study aims to determine the effectiveness of RSF to remove MPs. The artificial samples were made from plastics bags and tyre flakes which size were from 10 μm to more than 500 μm. Bentonite is added to represent a turbidity in the water. The average removal efficiency of plastics flakes before entering the filter was 50.48% (using bentonite) and 47.78% (without bentonite). Overall, the removal efficiency for the tyre flakes was 90.72% (using bentonite) and 93.03% (without bentonite). The filtration used in this study was varied between 4 and 10 m/h. Removal efficiency using RSF for plastic flakes on which Effective Size (ES) filter media 0.39 mm was 97.7% and on which ES 0.68 mm was 94.3%. Meanwhile, the removal efficiency of the tyre flakes for ES 0.39 mm were 90.6% and ES 0.68 mm was 85.2%. However, in this study, RSF mostly removed MPs particles greater than 200- μm in size.

Pilot plant study on ozonation and biological activated carbon process for drinking water treatment

1997 ◽  
Vol 35 (8) ◽  
pp. 21-28 ◽  
Author(s):  
Woo Hang Kim ◽  
Wataru Nishijima ◽  
Eiji Shoto ◽  
Mitsumasa Okada
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Water Treatment ◽  
Contact Time ◽  
Drinking Water Treatment ◽  
Suspended Solid ◽  
Residual Chlorine ◽  
Raw Water ◽  
Activated Carbon Adsorption ◽  
Biological Activated Carbon

A study on advanced drinking water treatment was conducted in a pilot scale plant taking raw water from Minaga Reservoir, Japan. Ozonation-biological activated carbon process (O3-BAC), BAC process (BAC) and chlorination-granular activated carbon adsorption process (Cl2-GAC) were evaluated based on the following parameters; dissolved organic carbon (DOC), adsorbable DOC (ADOC) and biodegradable DOC (BDOC). The raw water used was pre-treated by biofiltration for suspended solid removal and biological treatment. Contact time for ozonation and chlorination was 24 min. Empty bed contact time of activated carbon column was 15 min. Ozone dosage was 3 mg • 1−1. Chlorination was carried out to maintain a residual chlorine concentration of 0.2 mg • 1−1. Effluent DOC from biofiltration consisted of mainly ADOC (90%) and BDOC (10%). Therefore, DOC was mainly removed by adsorption in all processes. However, biodegradable DOC increased by 20% after ozonation in O3-BAC and was removed effectively by the attached bacteria on the activated carbon. Significant differences in DOC removal were not noted among the three processes during 8 months of operation. After the saturation of activated carbon, the effluent DOC from the O3-BAC was lower than that from BAC and Cl2-GAC. Ozonation improved biodegradability of organic substances and effluent water quality by the following biodegradation of biodegradable DOC by biological activated carbon.

The Relationship between Concentration and Sensory Properties of 2-Methylisoborneol and Geosmin in Drinking Water

1988 ◽  
Vol 20 (8-9) ◽  
pp. 11-17 ◽  
Author(s):  
T. Ito ◽  
T. Okumura ◽  
M. Yamamoto
Keyword(s):  
Drinking Water ◽  
Water Temperature ◽  
Forced Choice ◽  
Residual Chlorine ◽  
Mixing Ratio ◽  
Consumer Panel ◽  
Triangle Method ◽  
Musty Odor ◽  
The Relationship ◽  
Mixed Samples

The study of the relations between the senses of smell and taste and odorant concentration is important for the solution of odor problems. The threshold concentrations of odor and taste (TOC, TTC) of 2-methylisoborneol (MIB) and geosmin were measured by the non-forced choice triangle method using 12-20 panelists. Both TOC and TTC were found to be functions of water temperature and the concentration of residual chlorine. The TOC and TTC of mixed samples were rather lower than the concentrations calculated from the mixing ratio. The sensitivities of the consumer panel and the number of musty odor complaints from consumers are related to MIB or geosmin concentration. The ratio of the number of complaints to MIB (or geosmin) concentration decreased after maximum complaint, but the sensitivity of the consumer panel remained the same.

PTSA (pressure and thermal swing adsorption) method to remove trihalomethanes from drinking water

1997 ◽  
Vol 35 (7) ◽  
pp. 243-250 ◽  
Author(s):  
Shigekazu Nakano ◽  
Tomoko Fukuhara ◽  
Masami Hiasa
Keyword(s):  
Drinking Water ◽  
Residual Chlorine ◽  
Remarkable Difference ◽  
Adsorption Method ◽  
Heating And Cooling ◽  
Point Of Use ◽  
Thermal Swing Adsorption ◽  
Long Time ◽  
Musty Odor ◽  
Vacuum Heating

It has been widely recognized that trihalomethanes (THMs) in drinking water pose a risk to human health. THMs can be removed to a certain extent by the conventional point-of-use (POU) unit which is composed of activated carbon (AC) and microfilter. But it's life on THMs is relatively shorter than on residual chlorine or musty odor. To extent the life of AC adsorber, pressure and thermal swing adsorption (PTSA) was applied by preferential regeneration of chloroform. PTSA was effective to remove THMs, especially chloroform. Adsorption isotherms of chloroform at 25 and 70°C showed a remarkable difference so that thermal swing was considered effective. Chloroform was also desorbed by reducing pressure. By vacuum heating at 70°C, chloroform was almost desorbed from AC and reversible adsorption was considered possible. A prototype of POU unit with PTSA was proposed. Regeneration mode would consist of dewatering, vacuum heating and cooling (backwashing). The unit was maintained in bacteriostatic condition and could be used for a long time without changing an AC cartridge.

scholarly journals First Derivative UV Spectra of Surface Water as a Monitor of Chlorination in Drinking Water Treatment

2001 ◽  
Vol 1 ◽  
pp. 39-43 ◽  
Author(s):  
V. Zitko
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Surface Water ◽  
Distribution System ◽  
Drinking Water Treatment ◽  
Uv Spectra ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
First Derivative ◽  
Derivative Spectra

Many countries require the presence of free chlorine at about 0.1 mg/l in their drinking water supplies. For various reasons, such as cast-iron pipes or long residence times in the distribution system, free chlorine may decrease below detection limits. In such cases it is important to know whether or not the water was chlorinated or if nonchlorinated water entered the system by accident. Changes in UV spectra of natural organic matter in lakewater were used to assess qualitatively the degree of chlorination in the treatment to produce drinking water. The changes were more obvious in the first derivative spectra. In lakewater, the derivative spectra have a maximum at about 280 nm. This maximum shifts to longer wavelengths by up to 10 nm, decreases, and eventually disappears with an increasing dose of chlorine. The water treatment system was monitored by this technique for over 1 year and changes in the UV spectra of water samples were compared with experimental samples treated with known amounts of chlorine. The changes of the UV spectra with the concentration of added chlorine are presented. On several occasions, water, which received very little or no chlorination, may have entered the drinking water system. The results show that first derivative spectra are potentially a tool to determine, in the absence of residual chlorine, whether or not surface water was chlorinated during the treatment to produce potable water.

scholarly journals Cyanobacteria and microcystin contamination in untreated and treated drinking water in Ghana

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Gloria Naa Dzama Addico ◽  
Jörg D. Hardege ◽  
Jiri Kohoutek ◽  
Kweku Amoaku Atta DeGraft-Johnson ◽  
Pavel Babica
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Human Health ◽  
Metropolitan Area ◽  
Cyanobacterial Blooms ◽  
Maximal Concentration ◽  
Raw Water ◽  
Treated Water ◽  
Treated Drinking Water ◽  
Who Guideline

<p>Although cyanobacterial blooms and cyanotoxins represent a worldwide-occurring phenomenon, there are large differences among different countries in cyanotoxin-related human health risk assessment, management practices and policies. While national standards, guideline values and detailed regulatory frameworks for effective management of cyanotoxin risks have been implemented in many industrialized countries, the extent of cyanobacteria occurrence and cyanotoxin contamination in certain geographical regions is under-reported and not very well understood. Such regions include major parts of tropical West and Central Africa, a region constisting of more than 25 countries occupying an area of 12 million km<sup>2</sup>, with a total population of 500 milion people. Only few studies focusing on cyanotoxin occurrence in this region have been published so far, and reports dealing specifically with cyanotoxin contamination in drinking water are extremely scarce. In this study, we report seasonal data on cyanobacteria and microcystin (MC) contamination in drinking water reservoirs and adjacent treatment plants located in Ghana, West Africa. During January-June 2005, concentrations of MCs were monitored in four treatment plants supplying drinking water to major metropolitan areas in Ghana: the treatment plants Barekese and Owabi, which serve Kumasi Metropolitan Area, and the plants Kpong and Weija, providing water for Accra-Tema Metropolitan Area. HPLC analyses showed that 65% samples of raw water at the intake of the treatment plants contained intracellular MCs (maximal detected concentration was 8.73 µg L<sup>-1</sup>), whereas dissolved toxins were detected in 33% of the samples. Significant reduction of cyanobacterial cell counts and MC concentrations was achieved during the entire monitoring period by the applied conventional water treatment methods (alum flocculation, sedimentation, rapid sand filtration and chlorination), and MC concentration in the final treated water never exceeded 1 µg L<sup>-1</sup> (WHO guideline limit for MCs in drinking water). However, cyanobacterial cells (93-3,055 cell mL<sup>-1</sup>) were frequently found in the final treated water and intracellular MCs were detected in 17% of the samples (maximal concentration 0.61 µg L<sup>-1</sup>), while dissolved MCs were present in 14% of the final treated water samples (maximal concentration 0.81 µg L<sup>-1</sup>). It indicates a borderline efficiency of the water treatment, thus MC concentrations in drinking water might exceed the WHO guideline limit if the treatment efficiency gets compromised. In addition, MC concentrations found in the raw water intake might represent significant human health risks for people living in areas with only a limited access to the treated or underground drinking water.</p>

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