scholarly journals PERFORMANCE OF PRE-CHLORINATION, COAGULATION AND ADSORPTION FOR CONTROLLING THE FORMATION OF CARCINOGENIC COMPOUND IN TREATED WATER

2019 ◽  
Vol 12 (04) ◽  
pp. 2111-2115
Author(s):  
Euis Nurul Hidayah ◽  
Fauzul Rizqa ◽  
Okik Hendriyanto Cahyonugroho
1998 ◽  
Vol 38 (3) ◽  
pp. 127-134
Author(s):  
Jaap H. J. M. van der Graaf ◽  
Arjen F. van Nieuwenhuijzen

As yet, filtration of wastewater treatment effluent has not been practised in the Netherlands. The main objections were the expected high costs. In order to gain practical experience an investigation programme studied the applicability and optimization of effluent filtration. Especially multi-layer filtration with the addition of ironchloride seemed to be very effective. Very low concentrations of suspended solids and phosphorus were achieved, even at high filtration rates (up to 30 m/h). This leads to an impressive reduction of expected costs, down to Dfl. 0.02/m3 (treated water).


2018 ◽  
Vol 74 (7) ◽  
pp. III_415-III_422
Author(s):  
Yasushi ISHIGURO ◽  
Guangyu CUI ◽  
Tomonari FUJISAWA ◽  
Katsuhito YASUFUKU ◽  
Shinya OKUMURA ◽  
...  

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 354
Author(s):  
Md. Aminur Rahman ◽  
Sazal Kumar ◽  
A. S. M. Fazle Bari ◽  
Abhishek Sharma ◽  
Mohammad Mahmudur Rahman

Arsenic (As) removal plants were installed in As-endemic areas of Bangladesh to remove As from well water. In many cases, these removal plants did not perform satisfactorily. This study evaluated the efficiency of 20 As and iron (Fe) removal plants (AIRPs) during pre- and post-monsoon conditions in rural Bangladesh. Results revealed that As removal efficiencies ranged from 67% to 98% and 74 to 93% during the pre- and post-monsoons periods, respectively. In the post-monsoon season As removal at individual AIRP sites was on average (4.01%) greater than in the pre-monsoon season. However, two removal plants were unable to remove As below 50 µg L−1 (Bangladesh drinking water standard) during pre-monsoon, while 11 samples out of 20 were unable to remove As below the WHO provisional guideline value of 10 µg L−1. During post-monsoon, none of the samples exceeded 50 µg L−1, but eight of them exceeded 10 µg L−1. The Fe removal efficiencies of AIRPs were evident in more than 80% samples. Although As removal efficiency was found to be substantial, a cancer risk assessment indicates that hazard quotient (HQ) and carcinogenic risk (CR) of As in treated water for adults and children are above the threshold limits. Thus, additional reductions of As concentrations in treated water are needed to further reduce the excess cancer risk due to As in drinking water. Since 55% and 40% of the AIRPs were unable to remove As < 10 µg L−1 during pre-monsoon and post-monsoon, further improvement including changes in AIRP design, regular cleaning of sludge, and periodic monitoring of water quality are suggested. Future research is needed to determine whether these modifications improve the performance of AIRPs.


Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 380
Author(s):  
Yan Chen ◽  
Huiping Li ◽  
Weihai Pang ◽  
Baiqin Zhou ◽  
Tian Li ◽  
...  

Nanofiltration (NF) is a promising post-treatment technology for providing high-quality drinking water. However, membrane fouling remains a challenge to long-term NF in providing high-quality drinking water. Herein, we found that coupling pre-treatments (sand filtration (SF) and ozone–biological activated carbon (O3-BAC)) and NF is a potent tactic against membrane fouling while achieving high-quality drinking water. The pilot results showed that using SF+O3-BAC pre-treated water as the feed water resulted in a lower but a slowly rising transmembrane pressure (TMP) in NF post-treatment, whereas an opposite observation was found when using SF pre-treated water as the feed water. High-performance size-exclusion chromatography (HPSEC) and three-dimensional excitation–emission matrix (3D-EEM) fluorescence spectroscopy determined that the O3-BAC process changed the characteristic of dissolved organic matter (DOM), probably by removing the DOM of lower apparent molecular weight (LMW) and decreasing the biodegradability of water. Moreover, amino acids and tyrosine-like substances which were significantly related to medium and small molecule organics were found as the key foulants to membrane fouling. In addition, the accumulation of powdered activated carbon in O3-BAC pre-treated water on the membrane surface could be the key reason protecting the NF membrane from fouling.


Agriculture ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 86
Author(s):  
Regina Böger ◽  
Karl Rohn ◽  
Nicole Kemper ◽  
Jochen Schulz

Poor drinking water quality can affect pigs’ health and performance. The disinfection of water may enhance microbial water quality. In this study, bacteria and endotoxins in sodium hypochlorite-treated and -untreated water from one pig nursery were analyzed. Water samples were taken from incoming water and from compartments with treated and untreated water at the beginning and end of pipes and from nipples. The farm was visited 14 times to measure total bacteria counts and concentrations of Pseudomonas spp. and endotoxins. Additionally, the occurrence of coliform bacteria was analyzed. A mixed model analysis revealed significant reductions in total bacteria counts and Pseudomonas spp. in treated water at the beginning of pipes and at nipple drinkers. The differences between bacteria concentrations at the end of pipes had no clear trend. Endotoxin concentrations were approximately equal at the beginning of pipes and at nipple drinkers but were found to have differences at the end of pipes. The occurrence of coliform bacteria was significantly reduced in treated water. The application of sodium hypochlorite can significantly reduce bacteria in water pipes. Endotoxin concentrations were mostly unaffected by water treatment. Disinfection of the dead-end pipe sections failed, and thus these parts should be regarded as potential contamination sources.


2020 ◽  
Vol 55 (2) ◽  
pp. 184-197
Author(s):  
Saeideh Mirzaei ◽  
Beata Gorczyca

Abstract In this study, diffused aeration was applied to remove trihalomethane (THM) compounds from chlorinated, treated water containing high dissolved organic carbon (DOC) of 6.8 ± 1.2 mg/L. Increasing air-to-water volumetric ratio (rA/W) from 16 to 39 enhanced total THM (TTHM) removal from 60 to 70% at 20 °C and from 30 to 50% at 4 °C. Although bromodichloromethane has lower Henry's law constant than chloroform (CF), it was removed by a higher degree than CF in some aeration trials. Albeit obtaining high removals in aeration, TTHM reformed, and their concentration surpassed the Canadian guideline of 100 ppb in about 24 hours at 20 °C and 40 hours at 10 °C in all attempted air-to-water ratios. The water age in the system investigated in this study varied from 48 hours in midpoint chlorine boosting stations to 336 hours in the nearest endpoint. This study showed that THM removal by aeration is not a viable solution to control the concentration of these disinfection by-products in high-DOC treated water and in distribution systems where water age exceeds 24 hours; unless, it is going to be installed at the distribution endpoints.


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.


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