Low-cost Ceramic Filter Research Articles

Ceramic Filters for the Efficient Removal of Azo Dyes and Pathogens in Water

Overcoming the scarcity of safe and sustainable drinking water, particularly in low-income countries, is one of the key challenges of the 21st century. In these countries, the cost of centralized water treatment facilities is prohibitive. This work examines the application of low-cost ceramic filters as point-of-use (POU) devices for the removal of methylene blue, o-toluidine blue, Staphylococcus aureus, and Staphylococcus typhi from contaminated water. The ceramic filters had typical kaolinite functional groups, making them suitable for the removal of dyes and pathogens. Surface charge measurements indicated strongly anionic filters, while thermal properties confirmed the carbonization of the biowaste additive leaving behind a porous kaolinite structure which subsequently dehydroxylated into meta kaolinite. In addition, morphological data showed heterogeneous filter surfaces. Increased biomass content improved the permeability, water adsorption, flow rate, and apparent porosity of the filter. The ceramic filter removed methylene blue (42.99–59.74%), o-toluidine (79.95–92.71%), Staphylococcus aureus (98–100%), and Staphylococcus typhi (75–100%). Overall, the study demonstrated the effectiveness of POU ceramic filters in removing organic pollutants in contaminated water while serving as disinfectants.

Influence of iron, phosphate, and silicate on arsenic removal from groundwater using a low-cost ceramic filter.

The ceramic filter amended with iron (Fe) has proven to be a potential low-cost method for arsenic (As) removal from groundwater. The presence of Fe, phosphate (P), and silicate (Si) significantly affects the As removal efficiency of the ceramic filter, which has not been passably investigated. The present research aimed to examine the effect of Fe, P, and (or) Si presence as single or in combination on As (III) removal from synthetics groundwater by a low-cost iron amended ceramic filter (IACF). Laboratory-scale filtration experiments at different compositions of Fe, P, Si, and As (III) were conducted by the IACF fabricated with a ceramic candle and iron netting box. Fe (II) in synthetic groundwater positively impacted As (III) removal. At a concentration of 2mg/L of Fe (II), the As levels in the effluent decreased to less than the maximum contamination level (MCL) of 50 μg/L. Groundwater P concentration needed less than 3mg/L or Si concentrations required less than 35 mg/L to effectively reduce As (III) to below the MCL at 5mg/L of groundwater Fe (II). The cumulative effect of P and Si on As removal was found to be more significant than distinct contributions. The presence of 2mg/L P and 35 mg/L or higher Si in the groundwater cumulatively reduced the As removal performance from 92% to 63%, and the MCL was not met. The negative impact of P and Si on As (III) removal followed the order of (P + Si) > P > Si. P competed with As for adsorption sites during the process, while Si inhibited the Fe release and floc formation, significantly reducing As removal performance. The study findings can potentially contribute to optimizing IACF as a low-cost method for As removal from groundwater.

Water disinfection using durable ceramic filter coated with silver nanoparticles synthesized using actinomycetes

Contamination with pathogens degrades water quality and is a major cause of many waterborne diseases. The aim of this research is to reduce the global disease burden by presenting an efficient, durable, and low-cost ceramic filter impregnated with actinomycetes-mediated silver nanoparticles (AgNPs) for water disinfection in rural areas. This marks the first report on the simultaneous biosynthesis of AgNPs utilizing cell-free supernatants obtained from terrestrial actinomycetes. An easy and efficient method was used to impregnate AgNPs onto a ceramic filter using 3-aminopropyltriethoxysilane (APTES). The APTES linker is anchored to the ceramic surface through Si–O–Si bridges, while the terminal amino groups coordinate with AgNPs. Notably, the observed inhibition zone around the filter with AgNPs was ~ 18 mm, suggesting that the silver ions were responsible for the antibacterial activity. After 30 min of sonication, only insignificant traces of AgNPs were released from the filter, making it stable for long-term antibacterial activity when treating water. According to the laboratory simulation experiments, the untreated filter can reject about 99% of spiked bacteria, while the antibacterial efficiency of the filter coated with AgNPs was 100% due to the synergistic effect between filtration and disinfection with AgNPs. In addition, the average concentration of dissolved silver in the outlet water of the ultrafiltration system during three months was 33.7 μg/L, far below the permissible limit (100 μg/L) for drinking water. Overall, this work offers a suitable and affordable water treatment strategy for low-income, isolated, and rural societies in developing countries.

Low-cost ceramic filter bioreactor for treatment and reuse of residential septic tank effluent: A decentralized approach for small communities

Membrane biological reactors (MBRs) have recently become widely accepted as an advanced technology for treating domestic wastewater for improved water recovery, reuse, and recycling. The present study investigated the application of a low-cost ceramic filter bioreactor (CFBR) to treat septic tank effluent for smaller communities in Saudi Arabia (KSA). Filter fouling behavior, pollutant removal, and effluent quality were assessed under varying flux (0.2, 0.4, and 0.65 m/d) and aeration on/off cycle (60 min/60 min, 40 min/80 min, 30 min/90 min, 24 h/24 h) conditions. Operating CFBR at a flux value of 0.4 m/d ensured moderate fouling propensity, reasonable flux decline, and a higher volume of treated effluent. In the continuous aeration mode experiments, CFBR demonstrated the removal of various pollutants. Except for NO3N, CFBR effectively reduced all other pollutants of concern (BOD, COD, TSS, NH3N) in the effluent to acceptable levels meeting the water quality standards for unrestricted irrigation set by the KSA. An enhanced NO3N removal at the 24 h/24 h on/off cycle, indicating the effectiveness of cyclic aeration for promoting both nitrification/denitrification in the CFBR, with sufficient removal of other pollutants, is an original finding of the present study. Simple and cost-effective operations, high-quality effluent, and reduced energy consumption with shorter aeration duration promote the sustainability of the CFBR system for wastewater reclamation and reuse in small communities and rural settlements.

Development and evaluation of a low-cost ceramic filter for the removal of methyl orange, hexavalent chromium, and Escherichia coli from water

Lack of safe drinking water gives rise to waterborne diseases and other human health risks caused by various pollutants. Safe water provision in low-income countries is constrained by limited financial resources, and the problem is worsened during natural disasters. Thus, there is need to develop efficient low-cost technologies for point-of-use water treatment. Filtration using ceramic filters is a viable method as it uses locally available clay and biomass. The aim of this work was to develop and fabricate a laboratory-scale ceramic filter for water treatment, and to evaluate its capacity to remove Cr(VI), methyl orange (MO), and Escherichia coli 0157:H7 from water. Locally sourced clay and sawdust (SD) were used to fabricate filters with varying sawdust contents of 0, 2.5, 5, 10 and 30% (w/w). The clay-sawdust composites were fired in a muffle furnace at a heating rate of 200 °C/h up to 600, 750, and 900 °C for 3 h. Then the clay filter (CF) with the highest permeability was impregnated with silver nanoparticles (AgNP) to produce AgNP-CF. The surface charge, functional groups, surface morphology, and crystallinity of the filters were determined using the pH-drift method, Fourier transform infrared spectrometry, scanning electron microscopy, and X-ray powder diffraction, respectively. The permeability increased with biomass content and firing temperature. The AgNP-CF removed 57.3, 69.1, and 100% of Cr(VI), MO, and E. coli, respectively. Overall, the study demonstrated that AgNP-CF can potentially be used for water treatment in low-income communities.

Evaluation of a Low-Cost Ceramic Filter for Sustainable Reuse of Urban Stormwater in Arid Environments

Sustainable reuse of urban stormwater is inevitable in the fight against water crises in arid regions. This research aimed to evaluate the effectiveness of a low-cost ceramic filtration process for reuse applications of urban stormwater. Stormwater was collected from a storage pond located in Buraydah (Qassim, Saudi Arabia) for laboratory experiments. The filtration tests were performed in a continuous mode with constant pressure using a low-cost ceramic filter made of clay soil and rice bran. The removal rates of the contaminants (heavy metals) as well as the turbidity, suspended solids, and nutrients of the stormwater were assessed. High removal efficiencies for turbidity (97.4%), suspended solids (97.0%), BOD5 (78.4%), and COD (76.1%) were achieved while low removals were achieved for the nutrients: 19.7% for total nitrogen, 25.3% for nitrate, and 8.6% for phosphate. Removal efficiencies ranged between 36.2% and 99.9% for the heavy metals, i.e., iron, manganese, lead, zinc, nickel, copper, cadmium, selenium, and barium. Contaminant removal rates observed for the ceramic filter were also compared with the alum coagulation process operated in a continuous mode at an optimum alum dose of 50 mg/L. Similar removal behaviors for removal of turbidity, suspended solids, organics, nutrients, and heavy metals suggested that both ceramic filtration and alum coagulation can be effectively used for stormwater treatment. Effluent qualities of both the ceramic filter and alum coagulation met the standards, for recycling/reuse of wastewater, set by the Kingdom of Saudi Arabia and World Health Organization for unrestricted irrigation and toilet flushing. The study results revealed that ceramic filtration is a low-cost, energy efficient, and easy to maintain technology which can be complimentary to best management practices for stormwater.

Development and evaluation of treatment options for recycling ablution greywater

This study aimed to develop and evaluate five simplified AGW treatment options with or without low-cost ceramic filters, including direct ceramic filtration, alum coagulation–sedimentation, alum coagulation–sedimentation–ceramic filtration, alum coagulation–sedimentation–activated carbon, adsorption–sedimentation, and ceramic filtration–activated carbon adsorption–sedimentation. In raw AGW, concentrations of turbidity (14.8 NTU), TSS (24 mg/L), COD (63.2 mg/L), BOD (37.0 mg/L), and fecal coliform (884 MPN/100 mL) exceeded the greywater reuse standards for unrestricted irrigation, toilet flushing, and firefighting. In laboratory experiments, first three treatment options produced almost similar effluent with residual turbidity 1.5 NTU, COD 35 mg/L, and BOD 20 mg/L. Addition of the activated carbon to the last two treatment options enhanced the BOD and COD removals (< 12 mg/L). Multicriteria decision-making was performed to evaluate all the AGW treatment options against effluent water quality, treatment cost, land requirements, and need of skilled operators. Criteria weights were estimated using Entropy method, while the technique for order preference by similarity to ideal solution was used to final ranking of AGW treatment options. Results found direct filtration as the most feasible option to reuse AGW for restricted irrigation, and for unrestricted irrigation, toilet flushing, and firefighting, the ceramic filtration–activated carbon adsorption–sedimentation treatment process would be the more feasible option.

Study on the electrochemical characteristics of porous ceramic spacers in a capacitive deionization cell using slurry electrodes

Many studies have been conducted on flow-electrode capacitive deionization (FCDI), by which the limited ion adsorption capacity per unit cell can be extended, and which can be applied to high-salinity water treatment. Especially, using low-cost ceramic filters as three-dimensional (3D) electrode structure for FCDI is possible, instead of stacking the unit cells for scale-up. However, using ceramic partition walls as spacer can affect water flow and ion transport due to their thickness and porosity. Furthermore, the integrated membrane-spacer-assembly (MSA) having a membrane-coated spacer is more suitable for 3D electrode structure than a separated MSA having a spacer sandwiched between membranes. Herein we investigated the effects of the thickness and porosity of plate-type porous ceramic spacers on the electrochemical properties of the cell and compared the electrochemical properties of separated MSA with those of integrated MSA. Spacer porosity was found to have a larger effect than spacer thickness. Integrated MSA had larger resistance and lower capacitance than separated MSA, leading to lower desalination performance. It was attributed to the change in physical properties of the spacer induced by coating and the difference in ion exchange capacity of the coated membrane itself.

Application of a Low Cost Ceramic Filter for Recycling Sand Filter Backwash Water

The aim of this study is to examine the application of a low cost ceramic filter for the treatment of sand filter backwash water (SFBW). The treatment process is comprised of pre-coagulation of SFBW with aluminum sulfate (Alum) followed by continuous filtration usinga low cost ceramic filter at different trans-membrane pressures (TMPs). Jar test results showed that 20 mg/L of alum is the optimum dose for maximum removal of turbidity, Fe, and Mn from SFBW. The filter can be operated at a TMP between 0.6 and 3 kPa as well as a corresponding flux of 480–2000 L/m2/d without any flux declination. Significant removal, up to 99%, was observed forturbidity, iron (Fe), and manganese (Mn). The flux started to decline at 4.5 kPa TMP (corresponding flux 3280 L/m2/d), thus indicated fouling of the filter. The complete pore blocking model was found as the most appropriate model to explain the insight mechanism of flux decline. The optimum operating pressure and the permeate flux were found to be 3 kPa and 2000 L/m2/d, respectively. Treated SFBW by a low cost ceramic filter was found to be suitable to recycle back to the water treatment plant. The ceramic filtration process would be a low cost and efficient option to recycle the SFBW.

Application of Ceramic Filter for Improvement of Pond Sand Filter’s Water Quality

Paying attention to the use of surface water a household type filter unit adding with existing Pond Sand Filter (PSF) is introduced as an alternative water supply option where groundwater is contaminated with arsenic/iron or excessive saline and freshwater aquifers are not available. The performances of existing PSFs are not satisfactory due to poor operation and maintenance, shorter filter run and poor treated water quality. In this study a simple and low cost ceramic filter unit consists of clay pot (10L-capacity), ceramic filter core, storage tank and wooden stand, were applied. The combined action of PSF with ceramic filter unit, the average total coliform and fecal coliform removal efficiencies were found to be 99.73% and 99.97% respectively. Moreover, the reduction efficiencies of turbidity, and color were also achieved to be 96.89% and 99.90% respectively. The average discharge rate of the filter was observed to be 3.0 lit/hr. In combination with PSF, this kind of ceramic filter would be a reliable and sustainable treatment option particularly appropriate for problematic area in Bangladesh.

Microbiological effectiveness of locally produced ceramic filters for drinking water treatment in Cambodia

Low-cost options for the treatment of drinking water at the household level are being explored by the Cambodian government and non-governmental organizations (NGOs) working in Cambodia, where many lack access to improved drinking water sources and diarrhoeal diseases are the most prevalent cause of death in children under 5 years of age. The ceramic water purifier (CWP), a locally produced, low-cost ceramic filter, is now being implemented by several NGOs, and an estimated 100,000+households in the country now use them for drinking water treatment. Two candidate filters were tested for the reduction of bacterial and viral surrogates for waterborne pathogens using representative Cambodian drinking water sources (rainwater and surface water) spiked with Escherichia coli and bacteriophage MS2. Results indicate that filters were capable of reducing key microbes in the laboratory with mean reductions of E. coli of approximately 99% and mean reduction of bacteriophages of 90-99% over >600 litres throughput. Increased effectiveness was not observed in filters with an AgNO3 amendment. At under US$10 per filter, locally produced ceramic filters may be a promising option for drinking water treatment and safe storage at the household level.