scholarly journals Application of hybrid coagulation–ultrafiltration for decentralized drinking water treatment: impact on flux, water quality and costs

2019 ◽  
Vol 19 (7) ◽  
pp. 2163-2171
Author(s):  
S. G. Arhin ◽  
N. Banadda ◽  
A. J. Komakech ◽  
W. Pronk ◽  
S. J. Marks

Abstract Decentralized membrane-based water treatment represents an attractive and viable approach to safe water supply in low-income areas, but its widespread adoption requires cost-effective antifouling strategies. Although the antifouling mechanisms of Al-based coagulants have been widely investigated, there is little data about their impact on costs and treatment efficiency for decentralized membrane-based systems. In this study, a comparative assessment of two decentralized ultrafiltration (UF) units with and without polyaluminum chloride (PACl) coagulation was undertaken to evaluate the influence of coagulation on the fouling, water quality, and costs nexus. The results showed that PACl suppressed both total fouling and hydraulically irreversible fouling. A matched-pair analysis also revealed that PACl improved the permeate quality by enhancing the removal of particulates and dissolved organics. Compared with the conventional UF system, the hybrid coagulation–UF system contributed to a 21% increase in the flux rate, allowing for a 27% reduction in membrane area and thus, providing cost benefits in terms of both capital and operating costs. These results suggest that PACl coagulation is potentially a cost-effective antifouling method for decentralized membrane-based water systems.

Water ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 18 ◽  
Author(s):  
Robert Haas ◽  
Ruediger Opitz ◽  
Thomas Grischek ◽  
Philipp Otter

Natural water treatment techniques combined with engineered solutions were investigated at demonstration sites in Europe within the AquaNES project. Ultrafiltration is well-established in water treatment, but is not feasible for many water utilities due to its high operational costs compared to conventional treatment. These differences in cost are caused by membrane fouling and the associated cleaning required. This study aims to assess the economic and energetic operation factors based on studies of an out/in ultrafiltration treatment plant for river water and bank filtrate. The fouling potential of both raw water sources was investigated as well as the quality of the resulting water. In addition, the results show the potential utility of a combined approach utilizing bank filtration followed by ultrafiltration in drinking water treatment. In a separate consideration of the treatment process, the water quality does not fulfill the requirements of the German drinking water ordinance. A new method for the removal of dissolved manganese from the bank filtrate is presented by inline electrolysis. While this improves water quality, this also has a significant influence on fouling potential and, thus, on operating costs of ultrafiltration. These aspects lead to a fundamental decision for operators to choose between more costly ultrafiltration with enhanced microbiological safety compared to cost-effective but less stringent drinking water treatment via open filtration.


2013 ◽  
Vol 6 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A. Grefte ◽  
M. Dignum ◽  
E. R. Cornelissen ◽  
L. C. Rietveld

Abstract. To guarantee a good water quality at the customers tap, natural organic matter (NOM) should be (partly) removed during drinking water treatment. The objective of this research was to improve the biological stability of the produced water by incorporating anion exchange (IEX) for NOM removal. Different placement positions of IEX in the treatment lane (IEX positioned before coagulation, before ozonation or after slow sand filtration) and two IEX configurations (MIEX® and fluidized IEX (FIX)) were compared on water quality as well as costs. For this purpose the pre-treatment plant at Loenderveen and production plant Weesperkarspel of Waternet were used as a case study. Both, MIEX® and FIX were able to remove NOM (mainly the HS fraction) to a high extent. NOM removal can be done efficiently before ozonation and after slow sand filtration. The biological stability, in terms of assimilable organic carbon, biofilm formation rate and dissolved organic carbon, was improved by incorporating IEX for NOM removal. The operational costs were assumed to be directly dependent of the NOM removal rate and determined the difference between the IEX positions. The total costs for IEX for the three positions were approximately equal (0.0631 € m−3), however the savings on following treatment processes caused a cost reduction for the IEX positions before coagulation and before ozonation compared to IEX positioned after slow sand filtration. IEX positioned before ozonation was most cost effective and improved the biological stability of the treated water.


Author(s):  
Nguyet Thi-Minh Dao ◽  
The-Anh Nguyen ◽  
Viet-Anh Nguyen ◽  
Mitsuharu Terashima ◽  
Hidenari Yasui

The occurrence of pesticides even at low concentrations in drinking water sources might induce potential risks to public health. This study aimed to investigate the removal mechanisms of eight pesticides by the nitrifying expanded-bed filter using biological activated carbon media at the pretreatment of a drinking water plant. The field analysis demonstrated that four pesticides Flutolanil, Buprofezin, Chlorpyrifos, and Fenobucard, were removed at 82%, 55%, 54%, and 52% respectively, while others were not significantly removed. Under controlled laboratory conditions with continuous and batch experiments, the adsorption onto the biological activated carbon media was demonstrated to be the main removal pathway of the pesticides. The contribution of microorganisms to the pesticide removals was rather limited. The pesticide removals observed in the field reactor was speculated to be the adsorption on the suspended solids presented in the influent water. The obtained results highlighted the need to apply a more efficient and cost-effective technology to remove the pesticide in the drinking water treatment process. Keywords: biological activated carbon; drinking water treatment; nitrifying expanded-bed filter; pesticide removal.


2020 ◽  
Vol 705 ◽  
pp. 135779 ◽  
Author(s):  
Andrea M. Brunner ◽  
Cheryl Bertelkamp ◽  
Milou M.L. Dingemans ◽  
Annemieke Kolkman ◽  
Bas Wols ◽  
...  

2019 ◽  
Vol 5 (8) ◽  
pp. 1360-1370 ◽  
Author(s):  
Bofu Li ◽  
Benjamin F. Trueman ◽  
Mohammad Shahedur Rahman ◽  
Yaohuan Gao ◽  
Yuri Park ◽  
...  

Silicates represent an alternative drinking water treatment for colour and turbidity due to iron. They may avoid the drawbacks of polyphosphates: increased lead solubility, the potential for increased bacterial growth, and phosphorus in wastewater.


2020 ◽  
Vol 20 (6) ◽  
pp. 2106-2118
Author(s):  
Kassim Chabi ◽  
Jie Zeng ◽  
Lizheng Guo ◽  
Xi Li ◽  
Chengsong Ye ◽  
...  

Abstract People in remote areas are still drinking surface water that may contain certain pollutants including harmful microorganisms and chemical compounds directly without any pretreatment. In this study, we have designed and operated a pilot-scale drinking water treatment unit as part of our aim to find an economic and easily operable technology for providing drinking water to people in those areas. Our small-scale treatment unit contains filtration and disinfection (UV–C irradiation) stages to remove pollutants from source water. The water quality index was determined based on various parameters such as pH, temperature, dissolved oxygen, nitrate, nitrite, ammonium, phosphorus, dissolved organic carbon and bacteria. Water and media samples after DNA extraction were sequenced using Illumina MiSeq throughput sequencing for the determination of bacterial community composition. After the raw water treatment, the reduction of bacteria concentration ranged from 1 to 2 log10. The average removal of the turbidity, ammonium, nitrite, phosphorus and dissolved organic carbon reached up to 95.33%, 85.71%, 100%, 28.57%, and 45%, respectively. In conclusion, multiple biological stages in our designed unit showed an improvement of the drinking water quality. The designed drinking treatment unit produces potable water meeting standards at a lower cost of operation and it can be used in remote areas.


2014 ◽  
Vol 48 (5) ◽  
pp. 3084-3091 ◽  
Author(s):  
Mark V. E. Santana ◽  
Qiong Zhang ◽  
James R. Mihelcic

2013 ◽  
Vol 68 (8) ◽  
pp. 1757-1762 ◽  
Author(s):  
Krzysztof Piaskowski

Drinking-water treatment sludge (DWTS) is a by-product generated during the production of drinking water where iron hydroxides are the main component of the sludge. The aim of the study presented here was to determine the effectiveness of using ferric sludge from two underground water treatment stations to remove orthophosphates from a model solution. The analyses were performed in static conditions. The sludge was dosed in a dry and suspended form. Using sludge dried at room temperature and preparing the suspension again proved to be much less effective in orthophosphate removal than using a suspension brought directly from the station. An increase in process effectiveness with a decreasing pH was observed for all the analysed sludge. Due to the low cost and high capability, DWTS has the potential to be utilised for cost-effective removal of phosphate from wastewater.


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