Pilot scale studies on the removal of trace metal contaminations in drinking water treatment using chelating ion-exchange resins

2002 ◽  
Vol 2 (1) ◽  
pp. 25-35 ◽  
Author(s):  
D. Stetter ◽  
O. Dördelmann ◽  
H. Overath

Increasing nickel concentrations in groundwaters are causing treatment problems in some locations in Germany and other European countries. Ion exchange treatment using iminodiacetic acid resin was studied under various conditions in a pilot scale plant. Breakthrough curves show that nickel, cadmium and lead concentrations of below 100 μg/L can easily be reduced to 1% of the feed concentration. Assuming a minimum removal rate of 95% the treated volumes ranged from 75,000 bed volumes up to 195,000 bed volumes depending on flow rate and calcium concentration. The process has no impact on other chemical and microbiological water quality parameters. Ideally the feed water should be free from turbidity, iron and manganese, otherwise head loss will grow very fast because of high filtration rates and the small diameter of resin beads used in this process. Nevertheless, the ion exchange resin can be backwashed without increasing the metal concentration in the effluent. Ion exchange using iminodiacetic resins is therefore a suitable treatment process for the removal of heavy metals from drinking water.

2014 ◽  
Vol 955-959 ◽  
pp. 3408-3413 ◽  
Author(s):  
Hong Wei Sun

Comparative study on permanganate and ozone as pre-oxidation agents were performed on pilot scale with traditional drinking water treatment process, chemical oxygen demand (COD), total organic carbon (TOC), UV254, turbidity, trihalomethane formation potential (THMFP) were examined at each reactor’s effluent. The results show that at pre-oxidation reactor, the total organic remained stable after by the two agents, while for UV254, pre-ozonation has a removal rate of 34%, comparing that of 17% by permanganate. At the sedimentation process, 0.4 mg/L permanganate improves the removal rate of turbidity and COD by 0.99 % and 8.4%, respectively; while a positive COD removal of 11.8 % was achieved by 0.9 mg/L pre-ozonation, and an average of-10.08% turbidity removal was achieved at applied dosage (0.5, 0,9 and 1.5 mg/L), which can be made up for in the followed sand filtration reactor. Both permanganate and pre-ozonation show higher removal rate of THMFP for the finished water.


2019 ◽  
Vol 6 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Bahman Masoomi ◽  
Neamatollah Jaafarzadeh ◽  
Tayebeh Tabatabaie ◽  
Esmaeil Kouhgardi ◽  
Sahand Jorfi

Background: Ozone can be used as a single technology or in combination with other processes to improve the coagulation- flocculation or biodegradability in order to remove pollutants in natural water treatment. Methods: In this study, the effects of pre-ozonation with coagulant substances on the quality parameters of drinking water were investigated using humic acid, kaolin, clay, and green algae in a pilot scale. This study was conducted under laboratory conditions (at both acidic and alkaline pH in different dosages of ozone and coagulant at ozone contact time with simulated water sample (5-20 minutes) in different scenarios). Results: The highest removal efficiency of parameters in the state of pre-ozonation alone and preozonation with a coagulant was observed at contact time of 20 minutes, ozone dosage of 5 g/h, coagulant dosage of 25 mg/L, at alkaline pH along with a decrease in temperature. So that, the average removal rate of turbidity, total organic carbon (TOC), color, and chlorophyll a in contact time of 20 minutes was 76.9%, 52.8%, 66.6%, and 85%, respectively. However, compared to ozonation under similar conditions, the reduction in turbidity, TOC, color, and chlorophyll a was 36.13%, 24.4%, 32.13%, and 79.6%, respectively. Also, it was revealed that pre-ozonation with coagulant could effectively improve the removal of parameters. Conclusion: However, since pre-ozonation can be effectively used to improve the coagulation efficacy in the drinking water treatment, the pre-ozonation combined with coagulation is proposed as an alternative to conventional coagulation to improve the process of drinking water treatment plant.


2011 ◽  
Vol 11 (1) ◽  
pp. 107-112 ◽  
Author(s):  
A. Grefte ◽  
M. Dignum ◽  
S. A. Baghoth ◽  
E. R. Cornelissen ◽  
L. C. Rietveld

To guarantee a good water quality at the consumer’s tap, natural organic matter (NOM) should be (partly) removed during drinking water treatment. The objective of this research is to measure the effect of NOM removal by ion exchange on the biological stability of drinking water. Experiments were performed in two lanes of the pilot plant of Weesperkarspel in the Netherlands. The lanes consisted of ozonation, softening, biological activated carbon filtration and slow sand filtration. Ion exchange in fluidized form was used as pre-treatment in one lane and removed 50% of the dissolved organic carbon (DOC); the other lane was used as reference. Compared to the reference lane, the assimilable organic carbon (AOC) concentration of the finished water in the lane pretreated by ion exchange was 61% lower. The biofilm formation rate of the finished water was decreased with 70% to 2.0 pg ATP/cm2.day. The achieved concentration of AOC and the values of the biofilm formation rate with ion exchange pre-treatment showed that the biological stability of drinking water can be improved by extending a treatment plant with ion exchange, especially when ozonation is involved as disinfection and oxidation step.


2021 ◽  
Author(s):  
Qihui Gu ◽  
Jun Ma ◽  
Jumei Zhang ◽  
Weipeng Guo ◽  
Huiqing Wu ◽  
...  

Abstract Sand filter (SFs) are common treatment processes for nitrogen pollutants removal in drinking water treatment plants (DWTPs). However, the mechanisms on the nitrogen-cycling role of SFs are still unclear. In this study, 16S rRNA gene amplicon sequencing was used to characterise the diversity and composition of the bacterial community in SFs from DWTPs. Additionally, metagenomics approach was used to determine the functional microorganisms involved in nitrogen cycle in SFs. Our results showed that Proteobacteria, Acidobacteria, Nitrospirae, and Chloroflexi dominated in SFs. Subsequently, 85 high-quality metagenome-assembled genomes (MAGs) were retrieved from metagenome datasets of selected SFs involving nitrification, assimilatory nitrogen reduction, and denitrification processes. Read mapping to reference genomes of Nitrospira and the phylogenetic tree of the ammonia monooxygenase subunit A gene, amoA, suggested that Nitrospira is abundantly found in SFs. Furthermore, according to their genetic content, a nitrogen metabolic model in SFs was proposed using representative MAGs and pure culture isolates. Quantitative real-time polymerase chain reaction (PCR) showed that ammonia-oxidising bacteria (AOB) and archaea (AOA), and complete ammonia oxidisers (comammox) were ubiquitous in the SFs, with the abundance of comammox being higher than that of AOA and AOB. Moreover, we identified a bacterial strain with a high NO3-N removal rate as Pseudomonas sp., which could be applied in the bioremediation of micro-polluted drinking water sources. Our study provides insights into functional nitrogen-metabolising microbes in SFs of DWTPs.


2019 ◽  
Vol 24 (1) ◽  
pp. 135-163
Author(s):  
Jader Martínez Girón ◽  
Jenny Vanessa Marín-Rivera ◽  
Mauricio Quintero-Angel

Population growth and urbanization pose a greater pressure for the treatment of drinking water. Additionally, different treatment units, such as decanters and filters, accumulate high concentrations of iron (Fe) and manganese (Mn), which in many cases can be discharged into the environment without any treatment when maintenance is performed. Therefore, this paper evaluates the effectiveness of vertical subsurface wetlands for Fe and Mn removal from wastewater in drinking water treatment plants, taking a pilot scale wetland with an ascending gravel bed with two types of plants: C. esculenta and P. australis in El Hormiguero (Cali, Colombia), as an example. The pilot system had three upstream vertical wetlands, two of them planted and the third one without a plant used as a control. The wetlands were arranged in parallel and each formed by three gravel beds of different diameter. The results showed no significant difference for the percentage of removal in the three wetlands for turbidity (98 %), Fe (90 %), dissolved Fe (97 %) and Mn (98 %). The dissolved oxygen presented a significant difference between the planted wetlands and the control. C. esculenta had the highest concentration of Fe in the root with (103.5 ± 20.8) µg/g ; while P. australis had the highest average of Fe concentrations in leaves and stem with (45.7 ± 24) µg/g and (41.4 ± 9.1) µg/g, respectively. It is concluded that subsurface wetlands can be an interesting alternative for wastewater treatment in the maintenance of drinking water treatment plants. However, more research is needed for the use of vegetation or some technologies for the removal or reduction of the pollutant load in wetlands, since each drinking water treatment plant will require a treatment system for wastewater, which in turn requires a wastewater treatment system as well.


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