Bioaugmentation of pilot-scale slow sand filters can achieve compliant levels for the micropollutant metaldehyde in a real water matrix

A prospective environmental life cycle assessment (LCA) and financial cost assessment is performed to the application of bioaugmentation to sand filters in Danish waterworks, to remove 2,6-dichlorobenzamide (BAM) from drinking water resources. Based on pilot-scale and laboratory-scale data, we compare bioaugmentation to current alternative strategies, namely granular activated carbon (GAC) adsorption, and well re-location. Both assessments identified well re-location as the least preferred option, however, this result is very sensitive to the distance from the waterworks to the new well. When bioaugmentation is compared to GAC, the former has a lower impact in 13 impact categories, but if immobilized bacteria are used, the impacts are higher than for GAC in all impact categories. On the other hand, from a cost perspective bioaugmentation appears to be preferable to GAC only if immobilized bacteria are used.

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Turbidity removal by rapid sand filter using anthracite coal as capping media

Journal of Innovations in Engineering Education ◽

10.3126/jiee.v4i1.35142 ◽

2021 ◽

Vol 4 (1) ◽

pp. 69-73

Author(s):

Gopal Tamakhu ◽

Iswar Man Amatya

Keyword(s):

Comparative Analysis ◽

Water Treatment ◽

Bituminous Coal ◽

Pilot Scale ◽

Sand Filters ◽

Turbidity Removal ◽

Sand Filter ◽

Filter Materials ◽

Water Treatment Plants ◽

Anthracite Coal

Rapid sand filters are very common in all conventional water treatment plants. Capping of existing rapid sand filters can be the promising method of improving the performance of rapid sand filters. Capping is process in which upper sand bed layer of few cm is replaced with capping material. However, this technique is limited in India due to unavailability of filter materials apart from sand. Some materials suitable for capping are anthracite coal, PVC granules, bituminous coal, broken bricks, etc. The attempt is made to study the effect of capping of Rapid sand filters by the use of anthracite coal as a capping media by pilot scale study. A series of test runs and experiments using different influent turbidity were tried. The pilot scale study has shown very encouraging results. Comparative analysis shows that higher rate of filtration is possible along with higher filter run and less backwash requirement. In the present work, conventional rapid sand filter and capped rapid sand filter are compared.

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Development of new pathogen surrogates and synthetic DNA tracers for water applications

10.5194/egusphere-egu21-6583 ◽

2021 ◽

Author(s):

Liping Pang

Keyword(s):

Pilot Scale ◽

Great Promise ◽

Pathogen Removal ◽

Water And Wastewater Treatment ◽

Sand Filters ◽

Synthetic Dna ◽

Point Of Use ◽

Sand Aquifer ◽

Artificial Dna ◽

Limestone Sand

In recent years, we have conducted research into developing new pathogen surrogates and synthetic DNA tracers for water applications. Biomolecule-modified particles have been used to mimic Cryptosporidium, rotavirus and adenovirus with respect to their filtration removal and transport in porous media. Additionally, we have developed new DNA tracers as free DNA molecules or DNA-encapsulated biopolymer microparticles to track water contamination. DNA markers are also used to label some surrogates to facilitate their sensitive detection by using qPCR.The surrogates have been validated in laboratory conditions alongside the actual pathogens. The Cryptosporidium surrogates have been satisfactorily validated in alluvial sand, in limestone sand, in coagulation and rapid sand filtration studies. The rotavirus surrogates have been successfully validated in coastal sand aquifer media, in unmodified and hydrophobically modified quartz sand, and in stony alluvial soils under on-site wastewater applications. The research findings have demonstrated that these new surrogates significantly outperform the most commonly used existing surrogates, namely, unmodified microspheres for Cryptosporidium oocysts and MS2 phage for viruses. Working with the water industry, we have applied the Cryptosporidium surrogate to pilot-scale rapid sand filters and point-of-use domestic filters and determined its removal efficiencies in water filtration systems commonly used in New Zealand. The artificial DNA tracers have been validated in surface water, groundwater and soils, and they were readily trackable in a surface stream for up to 1 km.Our proof-of-concept studies suggest that the new pathogen surrogates and synthetic DNA tracers we have developed show great promise as new tools for water applications. The &#8216;micro mimics&#8217; approach has opened up a new avenue for assessing pathogen removal and transport in water systems without the risk and expense that accompany work with actual pathogens. With further validation, the new surrogates could be used to study pathogen removal and transport in subsurface media after the disposal of effluent and biosolids to land, and to assess the performance of filtration processes in water and wastewater treatment. With future up-scaling validation of the new synthetic DNA tracers, these tracers could be useful for concurrently tracking multiple pollution sources and pathways in freshwater environments.

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Estimation and modeling of direct rapid sand filtration for total fecal coliform removal from secondary clarifier effluents

Water Science & Technology ◽

10.2166/wst.2012.054 ◽

2012 ◽

Vol 65 (9) ◽

pp. 1615-1623 ◽

Cited By ~ 7

Author(s):

Yi Li ◽

Jingjing Yu ◽

Zhigang Liu ◽

Tian Ma

Keyword(s):

Grain Size ◽

Fecal Coliform ◽

Loading Rate ◽

Pilot Scale ◽

Size Distributions ◽

Sand Filters ◽

Loading Rates ◽

First Order Kinetics ◽

Secondary Clarifier ◽

Grain Size Distributions

The filtration of fecal coliform from a secondary clarifier effluent was investigated using direct rapid sand filters as tertiary wastewater treatment on a pilot scale. The effect of the flocculation dose, flow loading rate, and grain size on fecal coliform removal was determined. Direct rapid sand filters can remove 0.6–1.5 log-units of fecal coliform, depending on the loading rate and grain size distribution. Meanwhile, the flocculation dose has little effect on coliform removal, and increasing the loading rate and/or grain size decreases the bacteria removal efficiency. A model was then developed for the removal process. Bacteria elimination and inactivation both in the water phase and the sand bed can be described by first-order kinetics. Removal was successfully simulated at different loading rates and grain size distributions and compared with the data obtained using pilot-scale filters.

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Grain displacement during backwash of drinking water filters

Water Science & Technology Water Supply ◽

10.2166/ws.2020.300 ◽

2020 ◽

Author(s):

Loren Ramsay ◽

Feng Du ◽

Majbritt Lund ◽

Haiyan He ◽

Ditte A. Søborg

Keyword(s):

Grain Size ◽

Drinking Water ◽

Pilot Scale ◽

Sand Filters ◽

Active Biomass ◽

Four Dimensions ◽

Study Country ◽

Water Filters ◽

Practical Implications

Abstract Backwashing rapid sand filters causes inadvertent displacement of filter media grains from their previous depths. This displacement can affect the hydraulic function of filters by mixing or segregating media grains, and the function of biofilters through displacement of active biomass and coatings from proper depths. This study quantifies grain displacement in a pilot-scale filter using tracer grains of colored sand, glass beads, anthracite and garnet to determine the effect of grain size, density and shape on grain displacement. Statistical moments are used to describe the depth distributions resulting from displacement during backwashing. Results show that significant grain displacement occurs during backwash consisting of air scour, air-and-water wash and sub-fluidization water-only wash. Here, displacement is largely independent of grain size, density and shape. When fluidization backwash is used, greater displacement and more dependence on grain characteristics is seen. A variety of grain movement phenomena can be observed during the backwashing steps, indicating that grain movement and therefore the resulting displacement is highly inhomogeneous in four dimensions. These results have direct practical implications for the design of rapid sand filters and the optimization of backwashing procedures, while suggesting that the current widespread backwashing practice used in the case study country (Denmark) should be abandoned.

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Effects of earthworms on surface clogging characteristics of intermittent sand filters

Water Science & Technology ◽

10.2166/wst.2010.180 ◽

2010 ◽

Vol 61 (11) ◽

pp. 2881-2888 ◽

Cited By ~ 10

Author(s):

Dong-bo Wang ◽

Zi-yun Zhang ◽

Xiao-ming Li ◽

Wei Zheng ◽

Yan Ding ◽

...

Keyword(s):

Loading Rate ◽

Infiltration Rate ◽

Pilot Scale ◽

Effective Porosity ◽

Organic Loading Rate ◽

Hydraulic Characteristics ◽

Sand Filters ◽

Positive Role ◽

Simple Method ◽

Hydraulic Behaviour

Intermittent sand filters (ISFs) are effective and economical in treating wastewater, but they are easy to clog up. To explore a feasible and simple method to alleviate clogging, two pilot-scale ISFs were constructed, one of which contained earthworms and the other did not. During the operation, the effects of earthworms on the hydraulic behaviour of ISFs were investigated. The results showed that both ISFs exhibited good performance in wastewater treatment. However, they showed different hydraulic characteristics although operated at the same organic loading rate (approximately 300 g m−2 d−1). The ISF without earthworms clogged only after 53 d operation, and was partially recovered after 7 d resting, but after that, clogging occurred again, and more rapidly than the initial clogging event (40 d). However, water on the medium surface of the ISF with earthworms was not observed during the whole experiments. In addition, 11–13% of effective porosity and 0.015–0.026 cm s−1 of infiltration rate were measured in the upper 20 cm of the ISF at the end of the experiments. The facts demonstrated that earthworms played a positive role in alleviating clogging and earthworms fed filter could alleviate surface clogging effectively.

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Performance comparison of a pilot-scale membrane bioreactor and a full-scale sequencing batch reactor with sand filtration: treatment of low strength wastewater from a northern Canadian Aboriginal Community

Water Science & Technology ◽

10.2166/wst.2005.0671 ◽

2005 ◽

Vol 51 (6-7) ◽

pp. 483-490

Author(s):

K. Frederickson ◽

N. Cicek

Keyword(s):

Wastewater Treatment ◽

Membrane Bioreactor ◽

Cold Water ◽

Batch Reactor ◽

Pilot Scale ◽

Performance Comparison ◽

Batch Reactors ◽

Sand Filtration ◽

Sand Filters ◽

Aboriginal Communities

Northern Aboriginal communities in Canada suffer from poor wastewater treatment. Treatment systems on 75% of Manitoban Aboriginal communities produce substandard effluent despite the presence of sophisticated treatment systems. A 200-litre, pilot-scale membrane bioreactor (MBR) was established on the Opaskwayak Cree Nation to investigate the feasibility of MBRs in mitigating Aboriginal wastewater treatment issues. The pilot system was remote controlled and monitored via the Internet using the program pcAnywhere. The community utilized two existing sequencing batch reactors (SBR) and three sand filters for wastewater treatment. The community wastewater was relatively weak and highly fluctuating which led to poorly settling sludge that readily fouled the sand filters. A comparison study between the MBR and SBR was undertaken from September to December 2003. Operated at a 10-hour hydraulic retention time and 20-day solids residence time, the MBR outperformed the SBR and sand filtration on BOD and suspended solids removal. Furthermore, the MBR showed high levels of nitrification despite relatively cold water temperatures.

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Chemically enhanced gravel pre-filtration for slow sand filters: advantages and pitfalls

Water Science & Technology Water Supply ◽

10.2166/ws.2006.029 ◽

2006 ◽

Vol 6 (1) ◽

pp. 121-128

Author(s):

C.C. Dorea ◽

B.A. Clarke

Keyword(s):

Negative Impact ◽

Pilot Scale ◽

Sand Filtration ◽

Sand Filters ◽

Slow Sand Filtration ◽

Chemical Enhancement ◽

Dissolved Organics ◽

Efficiency And Effectiveness ◽

Slow Sand Filter ◽

Pre Treatment

The chemical enhancement of gravel (or roughing) filtration with coagulants, i.e. direct (gravel) filtration, has been proposed as a pre-treatment alternative for slow sand filters. However, studies have frequently focused on the efficiencies of the pre-filters in terms of reduction percentages. The effectiveness of the pre-treatment on the subsequent slow sand filtration is not usually cited or even evaluated. By incorporating a pilot-scale slow sand filter in our trials, both aspects of the pre-treatment process were assessed: efficiency and effectiveness. In terms of turbidity reductions, our results demonstrated that chemically enhanced pre-filtration was substantially more efficient (93.2 to 99.5%) than conventional pre-filtration (50.6 to 79.3); this was also observed in terms of reductions in the level of other parameters (i.e. thermotolerant faecal coliforms and dissolved organics). Yet, the use of a coagulant can have a negative impact on the slow sand filtration run.

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A pilot-scale investigation of ozonation and advanced oxidation processes at Choa Chu Kang Waterworks

Water Practice & Technology ◽

10.2166/wpt.2015.006 ◽

2015 ◽

Vol 10 (1) ◽

pp. 43-49 ◽

Cited By ~ 1

Author(s):

Jenny Wang ◽

Achim Ried ◽

Harald Stapel ◽

Yaning Zhang ◽

Minghui Chen ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Organic Contaminants ◽

Advanced Oxidation Processes ◽

Advanced Oxidation ◽

Electrical Energy ◽

Pilot Scale ◽

Oxidation Processes ◽

Water Matrix ◽

Electrical Energy Per Order ◽

Efficient Option

A two-year comprehensive advanced oxidation processes (AOPs) pilot test was completed for a Singapore waterworks in 2011–2013. This study focused on oxidative removal of spiked organic contaminants with ozone and ozone-based AOPs (ozone application together with hydrogen peroxide, which is necessary for AOPs). The ‘optimized H2O2 dosage’ test philosophy was verified during the test period – keeping the residual ozone at 0.3 mg/L in the water for disinfection purpose by minimizing the H2O2 dosage. This study also monitored the bromate concentration in both ozone- and AOP-treated water, and all the samples reported below the laboratory detection limit (<5 µg/L), which is also lower than the WHO Guidelines for Drinking Water Quality (<10 µg/L). For comparison, a low pressure UV-based AOP test was conducted in the final stage of the study. The electrical energy per order (EEO) value is compared with ozone- and UV-based AOPs as well. The results indicated that ozone-based AOP with an optimized hydrogen peroxide dosage could be the most energy efficient option for this specific water matrix in terms of most selected compounds.

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Pilot scale testing of advanced oxidation processes for degradation of geosmin and MIB in recirculated aquaculture

Water Science & Technology Water Supply ◽

10.2166/ws.2010.246 ◽

2010 ◽

Vol 10 (2) ◽

pp. 217-225 ◽

Cited By ~ 10

Author(s):

M. M. Klausen ◽

O. Grønborg

Keyword(s):

Advanced Oxidation Processes ◽

Negative Impact ◽

Tap Water ◽

Advanced Oxidation ◽

Pilot Scale ◽

Oxidation Processes ◽

Water Matrix ◽

Degradation Rates ◽

Increased Risk ◽

The Impact

The presence of geosmin and 2-methylisoborneol (MIB) in recirculated aquaculture systems has a significant negative impact on the fish production due to poor flavour quality of produced fish and increased risk of rejection by fish processers. Advanced Oxidation Processes has a high potential for removal of geosmin and MIB in water and in this study UV/H2O2 and UV/O3 has been tested in pilot scale in real aquaculture process water. First order degradations constants were between 0.6 (UV/O3) and 1.2 (UV/H2O2) h−1 for geosmin and 1.3 (UV/O3)–1.5 (UV/H2O2) h−1 for MIB. This corresponded to average half-lives between 34–69 minutes for geosmin and between 28–32 minutes for MIB. These values were one order of magnitude higher than previously reported for degradation of geosmin and MIB in demineralised and tap-water. The slower degradation rates were caused by competitive and inhibitive processes from the water matrix. The influence of the water matrix also caused increased energy consumption with EEO values 16 to 38 times higher than previously reported for geosmin and MIB removal in tap water. Improved feasibility of removing geosmin and MIB in recirculated aquaculture systems by AOPs requires pre-treatment to minimize the impact of the water matrix on the degradation kinetics.

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