scholarly journals Treatment of arsenic-contaminated water using in-line electrolysis, co-precipitation and filtration in Costa Rica

2017 ◽  
Vol 18 (1) ◽  
pp. 40-48 ◽  
Author(s):  
Sylvie Kunz ◽  
Luis G. Romero-Esquivel ◽  
Philipp Otter ◽  
Ulrike Feistel ◽  
Thomas Grischek ◽  
...  

Abstract A novel treatment was tested with groundwater to investigate its arsenic removal under natural conditions. The system utilised in-line electrochlorination to oxidise water constituents without the need for external chemical supply. The oxidised arsenic and iron co-precipitated and were filtered via Greensand Plus™. The filter was catalytically active and provided an emergency oxidant. The system had only a few maintenance requirements due to online water quality monitoring. The contaminant removal during the field test in Costa Rica was impaired by strong fluctuations in water quality including low iron concentrations. However, the system removed on average 68% of the arsenic. Mean values of arsenic were 40 ± 23 μg/L in groundwater and 13 ± 6 μg/L in treated water. Iron was removed from an average of 2.8 ± 2.4 mg/L to 0.2 ± 0.2 mg/L (93% removal). Free chlorine produced and available in the treated water tank had a mean concentration of 1.25 mg/L and 0.64 mg/L, respectively.

Author(s):  
Yaser Ibrahim Jasem ◽  
Qassem H. Jalut ◽  
Salah N. Farhan ◽  
Muataz H. Ismael

In this work, a set of physical, chemical and biological parameters were analysed for Khirisan river from the period extending from December 2017up to November 2018. The samples were selected from three different sites, agricultural, commercial and residential area to assess the water quality of the river for drinking and irrigation purposes. The study showed that a number of diversity factors were recognized which have a direct effect on the quality of Khirisan river. This includes the catchment feeding area of the river, untreated domestic sewage from the restaurants, cafeterias and government buildings which are adjacent to the river. Water quality of Khirisan river, according to the Iraqi and international standards, satisfies the limits of the rules of the drinking purposes for all studied parameters except the values of calcium ions and total hardness value for some rainy months as well as to organic load. The mean values of BOD5 and COD for the three sites were 7.7 and 36 mg/l. In terms of irrigation purposes, the water quality of the river can be considered low to medium damage in terms of salinity and sodium hazards. In terms of chloride risk, there are no toxicity problems to the roots and leaves of the plants. Therefore, it requires a continual intensive water quality monitoring program to reduce its impact.


2020 ◽  
Vol 24 (7) ◽  
pp. 1217-1222
Author(s):  
U.E. Jonah ◽  
E.S. Iwok ◽  
H.E. Hanson

A study was carried out at the supper segment of Qua Iboe River from November, 2018 to August, 2019 in four sampling stations to assess the  impacts of coastal activities on water quality. Water samples were collected monthly and analyzed using standard procedures of Associations of Official Analytical Chemist and American Public Health Association. The stations comparisons and location of significant differences were carriedout using ANOVA and Least Significant Difference (LSD) test, while paired sample t-test were employed to compare the seasonal difference. The mean ranged values of water temperature were (25.03 – 25.330C), pH (5.8 –6.6 mg/l), DO(3.11 - 5.45 mg/l), TDS (18.63 – 32.53mg/l), EC  (8.33-13.16􀀁s/cm), Turbidity (7.61 – 18.32 NTU), TSS (90.80 - 165.63 mg/L), NO3 -1(33.02 – 78.33mg/l), P04 3-(4.44 – 7.39mg/l), Cl-(43.60 – 63.21mg/l), COD(35.96 – 113.05mg/l), NH3(0.33 – 0.62 mg/l). Mean values of TSS, EC, TSS, NO3, PO4 3-, NH3 and turbidity were higher in wet season, while water temperature, pH, DO, Cl- and COD values obtained were higher in dry season. Spatial variations in parameters were ascribed to levels of  anthropogenic activities and wastes discharged within the stations; the seasonal variations were emanated from influx of wastes, and dilution as result of surface run-offs during wet season. Based on the findings, the WQI values were poor for human consumption; especially from station 2 to4.These calls for urgent attention by Federal / State Ministry Health and Environment regards to its effects on human health and consistent water quality monitoring should be put into consideration. Keywords: Impact, Assessment, Coastal activities, Water Quality, Qua Iboe River Keywords: Impact, Assessment, Coastal activities, Water Quality, Qua Iboe River


2005 ◽  
Vol 52 (8) ◽  
pp. 87-94 ◽  
Author(s):  
K. Ohno ◽  
A. Furukawa ◽  
K. Hayashi ◽  
T. Kamei ◽  
Y. Magara

Serious arsenic contamination of groundwater in Bangladesh has been frequently reported and is of great concern. In this research, repeated water sampling from the same 10 tubewells in Nawabganj municipality, Bangladesh, was conducted and analysed, focusing on the seasonal variation of water quality and the relationship among arsenic and other metals and ions. For the seasonal variation of water quality, arsenic and iron concentrations were higher in the rainy season in general although the tendency was not consistent and it depended on the tubewell and the time. Correlation between arsenic and iron could not be observed in this study (r = −0.01) when using all cases. This was because no correlation was observed in the higher arsenic concentration range. Arsenic removal by co-precipitation with coexisting iron is known as one of the locally applicable techniques in Bangladesh, but the result from this study suggests that some additional treatments such as the extra injection of iron should be performed in some cases, especially where the arsenic concentration is high. The correlation between arsenic and other substances was also analysed. As a result, manganese (r = 0.37), molybdenum (r = 0.33) and sulfate ion (r = −0.33) significantly correlated with arsenic (p<0.05). The negative correlation between arsenic and sulfate ion implies the dissolution of arsenic into groundwater under reductive conditions although there are some exceptional cases.


2013 ◽  
Vol 133 (8) ◽  
pp. 1616-1624
Author(s):  
Zu Soh ◽  
Kentaro Miyamoto ◽  
Akira Hirano ◽  
Toshio Tsuji

2016 ◽  
Vol 15 (5) ◽  
pp. 1069-1074 ◽  
Author(s):  
Violeta-Monica Radu ◽  
Alexandru Anton Ivanov ◽  
Petra Ionescu ◽  
Gyorgy Deak ◽  
Marian Tudor

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