Rapid Sand Filtration Research Articles

Emergence of microplastics in African environmental drinking water sources: A review on sources, analysis and treatment strategies

The emergence of microplastics (MPs) as microcontaminants in environmental drinking water sources is a problem in Africa that requires immediate action. Therefore, this review focused on understanding the sources of MPs in African water systems, treatment strategies, analytical methods for identification and quantification, and Africa's pollution index. From the findings, the source of MPs in African water systems was attributed to unregulated importation of plastic products, poor waste management, lack of awareness, poor environmental value system and the inability of local polymer industries to adjust to new policies on plastic management. Most studies identified microfibers and microbeads to be the primary sources of plastics that break down to MPs in African drinking water sources, with polystyrene (PS), polypropylene (PP), and polyethylene (PE) being frequently detected. Current methods for identification, and quantification of MPs in most studies conducted in Africa were not developed in Africa but was adopted from developed countries and, in some cases, modified to meet specific analytical requirements. More studies are necessary for in-depth understanding of the fate and pollution index of MP in African environmental water systems. Furthermore, the interaction between MP and other pollutants in the water system still needs to be better understood. This review suggests membrane and rapid sand filtration methods as promising methods that may be considered for removing MPs from water systems in Africa.

Operational management of water quality to prevent physical, chemical, and microbial contaminations in hydroponic cultivation

ABSTRACT The overarching aim of the present research is to manage the quality of surface water and irrigation water in hydroponic cultivation, which is one of the sustainable modern agricultural methods. It fully covered the control of physical, chemical, and biological contamination within the recommended standard range from river water to irrigation water. Initially, to deal with the corresponding contamination levels, the performance of the combination of coagulation and flocculation, rapid sand filter, ultrafiltration, and ultimately reverse osmosis methods were examined. By optimizing the pre-treatment section of coagulation and flocculation with jar tests, more than 90% removal of colloidal materials was achieved. Following the optimization of pre-treatment section, an 18.7% reduction in water consumption was observed. Finally, through the examination of the irrigation system and monitoring of both physical and biological contaminations, alongside the optimization of the greenhouse's recycled water disinfection system, preventive measures inhibiting the irrigation system clogging were implemented. The findings of the current research exhibited the removal of over 99% of these contaminations yielding a 99% reduction in the occurrence of irrigation system clogging.

Direct filtration of low-turbidity water by fixed-bed ion exchange treatment

In drinking water treatment, low-turbidity water (e.g., < 5 NTU) is often purified by direct filtration comprising coagulation, flocculation, and rapid sand filtration. This study assessed the potential of replacing the rapid sand filter with a fixed-bed ion exchange column. Two types of anion exchange resins, polyacrylic (Purolite A860) and polystyrene (Purolite A502PS), were used in fixed-bed columns without preceding coagulation and flocculation. After the first use of the new resins (14-h operation), the A860 column showed more significant head loss buildup than the A502PS column (151 and 101 cm, respectively). This can be attributed to the effective size of A860 resins (0.38 mm), which was smaller than that of A502PS resins (0.52 mm). A860 resins were superior to A502PS resins in filtrate quality. The A860 resins achieved filtrate turbidity (0.16–0.26 NTU) lower than the A502PS resins (0.19–0.35 NTU). Similarly, dissolved organic carbon removal by A860 resins (25–37 %) was higher than that by A502PS resin (15–25 %) due to the low hydrophobicity of the feed water. Air scouring and water backwashing were ineffective in regenerating A860 resins. In contrast, cleaning with a NaCl solution (pH = 12) partially recovered the capacity of A860 resins for turbidity removal.

Shifting to biology promotes highly efficient iron removal in groundwater filters

Rapid sand filters are established and widely applied technologies for groundwater treatment. In these filters, main groundwater contaminants such as iron, manganese, and ammonium are oxidized and removed. Conventionally, intensive aeration is employed to provide oxygen for these redox reactions. While effective, intensive aeration promotes flocculent iron removal, which results in iron oxide flocs that rapidly clog the filter. In this study, we operated two parallel full-scale sand filters at different aeration intensities to resolve the relative contribution of homogeneous, heterogeneous and biological iron removal pathways, and identify their operational controls. Our results show that mild aeration in the LOW filter (5 mg/L O2, pH 6.9) promoted biological iron removal and enabled iron oxidation at twice the rate compared to the intensively aerated HIGH filter (>10 mg/L O2, pH 7.4). Microscopy images showed distinctive twisted stalk-like iron solids, the biosignatures of Gallionella ferruginea, both in the LOW filter sand coatings as well as in its backwash solids. In accordance, 10 times higher DNA copy numbers of G. ferruginea were found in the LOW filter effluent. Clogging by biogenic iron solids was slower than by chemical iron flocs, resulting in lower backwash frequencies and yielding four times more water per run. Ultimately, our results reveal that biological iron oxidation can be actively controlled and favoured over competing physico-chemical routes. The production of more compact and practically valuable iron oxide solids is of outmost interest. We conclude that, although counterintuitive, slowing down iron oxidation in the water before filtration enables rapid iron removal in the biofilter.

Microplastics in anaerobic digestion: occurrence, impact, and mitigation strategies.

Microplastic pollution has emerged as a global environmental concern, with pervasive contamination in terrestrial and aquatic ecosystems. This review paper delves into the intricate dynamics of microplastics within anaerobic digestion systems, addressing their occurrence, impact, and potential mitigation strategies. The occurrence of microplastics in anaerobic digesters is widespread, entering these systems through diverse inputs, such as sewage sludge, organic waste, and etc. Microplastics in anaerobic digestion have been associated with potential adverse impacts on biogas production, process performance, microbial communities, and degradation processes, though the relationship is complex and context dependent. This review highlights the urgent need for comprehensive research into the fate of microplastics within anaerobic digesters. Mitigation strategies offer promise in alleviating microplastic contamination, with advanced separation methods, innovative techniques such as magnetic micro-submarines, photocatalytic micro-motors, membrane bioreactors combined with activated carbon filters, rapid sand filtration, or conventional activated sludge, and disintegration-oriented techniques such as electrocatalysis, biodegradation, and thermal decomposition. Nonetheless, there is a significant knowledge gap that necessitates further research into the fate and long-term effects of microplastics in digestate. Collaborative efforts are crucial to addressing this emerging concern and ensuring the sustainability of anaerobic digestion systems in the face of microplastic challenges.

A difficult coexistence: Resolving the iron-induced nitrification delay in groundwater filters

Rapid sand filters (RSF) are an established and widely applied technology for the removal of dissolved iron (Fe2+) and ammonium (NH4+) among other contaminants in groundwater treatment. Most often, biological NH4+oxidation is spatially delayed and starts only upon complete Fe2+ depletion. However, the mechanism(s) responsible for the inhibition of NH4+oxidation by Fe2+ or its oxidation (by)products remains elusive, hindering further process control and optimization. We used batch assays, lab-scale columns, and full-scale filter characterizations to resolve the individual impact of the main Fe2+ oxidizing mechanisms and the resulting products on biological NH4+ oxidation. modeling of the obtained datasets allowed to quantitatively assess the hydraulic implications of Fe2+ oxidation. Dissolved Fe2+ and the reactive oxygen species formed as byproducts during Fe2+ oxidation had no direct effect on ammonia oxidation. The Fe3+ oxides on the sand grain coating, commonly assumed to be the main cause for inhibited ammonia oxidation, seemed instead to enhance it. modeling allowed to exclude mass transfer limitations induced by accumulation of iron flocs and consequent filter clogging as the cause for delayed ammonia oxidation. We unequivocally identify the inhibition of NH4+oxidizing organisms by the Fe3+ flocs generated during Fe2+ oxidation as the main cause for the commonly observed spatial delay in ammonia oxidation. The addition of Fe3+ flocs inhibited NH4+oxidation both in batch and column tests, and the removal of Fe3+ flocs by backwashing completely re-established the NH4+removal capacity, suggesting that the inhibition is reversible. In conclusion, our findings not only identify the iron form that causes the inhibition, albeit the biological mechanism remains to be identified, but also highlight the ecological importance of iron cycling in nitrifying environments.

Impact of the reductive deiodination on the sorption of iodinated X-ray contrast media to filter sand and activated carbon

Iodinated X-ray contrast media (ICM) and their aerobic transformation products (TPs) are widespread in the aquatic environment due to their persistent and mobile character. In a previous lab study, we have shown that the reductive (partial) deiodination of selected triiodobenzene derivatives increases the sorption to aquifer sand and loam soil, since iodine affects the compounds by steric hindrance, repulsive forces, resonance and inductive effects. These results suggest that the (partial) deiodination generally occurring to ICM and aerobic ICM TPs during anoxic/anaerobic bank filtration has a potential to increase their removal by sorption to natural sorbents. To basically assess the sorption potential to technically applied materials for drinking water treatment subsequent to bank filtration, we investigated the sorption of iopromide, diatrizoate and 5-amino-2,4,6-triiodoisophtalic acid and their di, mono and deiodinated structures to used filter sand from a waterworks and different fresh powdered activated carbons in batch tests using Berlin drinking water. The filter material, coated by iron and manganese oxides as well as organic material (including biofilm), preferentially removed monoiodinated derivatives, but diffusion through the organic layer heavily slowed the sorption. Therefore, the removal potential by sorption in rapid sand filters of waterworks for (partially) deiodinated benzene derivatives is suggested to be low. The deiodination of iopromide and diatrizoate significantly increased the sorption affinity to activated carbon and the competitiveness with regard to drinking water DOC. Despite the large atom radius of iodine, no clear correlation was found between the pore characteristics of the activated carbons and the molecular size of the compounds. This study emphasises the importance of anoxic/anaerobic conditions for the removal of persistent and mobile ICM and ICM TPs during drinking water treatment.

Treating wastewater for microplastics to a level on par with nearby marine waters

Retention of microplastics (MPs) at the third largest wastewater treatment plant (WWTP) in Sweden was investigated. The plant is one of the most modern and advanced of its kind, with rapid sand filter for tertiary treatment in combination with mechanical, biological, and chemical treatment. It achieved a significantly high treatment efficiency, which brought the MP concentration in its discharge on par with concentrations measured in marine waters of the same region. This novel data shows that properly designed modern WWTPs can reduce the MP content of sewage down to background levels measured in the receiving aquatic environment. Opposite to current understanding of the retention of MP by WWTPs, a modern and well-designed WWTP does not have to be a significant point source for MP. MPs were quantified at all major treatment steps, including digester inlet and outlet sludge. MPs sized 10–500 µm were analyzed by a focal plane array based micro-Fourier transform infrared (FPA-µFTIR) microscopy, a hyperspectral imaging technique, while MPs above 500 µm were analyzed by Attenuated Total Reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. Mass was estimated from the hyperspectral images for MPs <500 µm and from microscope images >500 µm. The overall treatment efficiency was in terms of MP counts 99.98 %, with a daily input of 6.42 × 1010 and output of 1.04 × 107 particles. The mass removal efficiency was 99.99 %. The mechanical part of the treatment, the pre-treatment, and primary stages, reduced both the MP counts and mass by approximately 71 %. The combined biological treatment, secondary settling, and final polishing with rapid sand filtration removed nearly all the remaining 29 %. MPs became successively smaller as they passed the different treatment steps. The digester inlet received 1.04 × 1011 MPs daily, while it discharged 9.96 × 1010 MPs, causing a small but not significant decrease in MP counts, with a corresponding MP mass reduction of 9.56 %.

Synthesis, characterization, and breakthrough modeling of low-cost graphene oxide-sand supported adsorbent filter for the separation of lead and chromium ions

The existence of lead and chromium ions in waterbodies severely affects the biological activities of aquatic creatures that directly affect human health. A graphene oxide-sand (GO-sand)-based composite filter has been successfully used as a Rapid Sand Filter (RSF) to remove Lead (II) and Chromium (III) ions in water. Boehm titration, FTIR, RAMAN, XRD, and SEM-EDX analyses confirmed GO-sand’s active sites, semicrystalline, and irregular morphology. Moreover, lead and chromium adsorption using a GO-sand composite was established by XPS and SEM-EDX analyses. The results of the batch study showed significant adsorption (289.68 mg g−1 and 258.87 mg g−1) along with significant removal (96.4 % and 95.6 %) of Pb (II) and Cr (III), respectively. Among Langmuir, Freundlich, and Liu isotherms, the adsorption isotherm showed an excellent fit with Liu isotherm. The response surface methodology (RSM) study suggested adequate quadratic models and exceptional covenant between the predicted and actual figures with a significant coefficient determination (R2 > 0.920). The kinetic study finding revealed the best fit for the Elovich kinetic model (R2 = 0.995 (Pb), R2 = 0.967 (Cr)), and the thermodynamics study confirmed endothermic adsorption. Pareto analysis confirmed that solution pH was the most significant parameter towards adsorption. Furthermore, the regenerated adsorbent demonstrated practical reusability up to four adsorption–desorption cycles, revealing the process’s sustainability.

Perencanaan Sistem Penyediaan Air Bersih di Desa Teluk Melano Kecamatan Simpang Hilir Kabupaten Kayong Utara

The lack of access to clean water services had led a significant portion of the community in Teluk Melano Village to rely on river water and rainwater as their primary sources to meet their needs. Teluk Melano Village has the highest population in the Simpang Hilir District, Kayong Utara Regency. As of now, Teluk Melano Village does not have a Clean Water Supply System (BPAM). Therefore, a study was needed to meet the demand for clean water by conducting a Clean WaterTreatment Plant (IPA Bersih) Planning for Teluk Melano Village. This study aimed to design a clean water supply system with a planning period of the next 15 years (2023-2037). The method used involved primary data collection based on SNI 6989.57.2008 and SNI 8066:2015, and secondary data collection sourced from the Teluk Melano Village Monograph for the years 2020 and 2022. The total demand for clean water in Teluk Melano Village in 2037 would be 3.39 liters/second with a population of 1930 people. The results of the water quality test of the Melani River in this study showed that the parameters of E-coli, color, and pH, based on Government Regulation No. 22 of 2021, Class1, on the Implementation and Management of the Environment, did not meet the standard quality requirements for clean water. The planned Water Treatment Plant (WTP) included a complete conventional treatment process, including coagulation using hydraulic type rapid mixing utilizing gravity on the waterfall, flocculation using vertical baffled channels, sedimentation using plate settlers to reduce turbidity, filtration using rapid sand filters with filter media consisting of quartz sand and support media consisting of gravel, disinfection using chemical disinfectant in the form of chlorine solution, neutralization using a dosing pump for the addition of lime, and the type of reservoir used is a ground reservoir.Keywords: clean water, Water Treatment Plant, Teluk Melano Village

Performance of Rapid Sand Filter Dual Media for Microplastic Removal in the Water: The Effect of Microplastic Size and Effective Size of Filter Media

Microplastics (MPs) significantly damage the environment and human health, leading to a growing global concern. MPs have been detected not only in the natural environment but also in the drinking water treatment process. One of the configurations of the drinking water treatment unit is filtration. Only a few research studies have been published on microplastic removal in the water system. This study was conducted to determine the performance of a rapid sand filter (RSF) in removing microplastics in water with a variation in the effective size (ES) of silica sand and microplastic size. In this study, microplastics are artificially made with size variations of &lt; 400 μm and &gt;400 μm. The filtering uses two variations in the adequate size (ES) of silica sand, namely 0.4 mm and 0.7 mm. At the same time, anthracite is only a control variable with ES = 0.69 with a flow speed of 4 m / h and an observation time of 30, 60, 90, and 120 minutes. The results show that the filter media ES 0.4 has the highest efficiency values of 91.30% for the microplastic size MPs &lt;400 µm and 95.80 % for the larger microplastic &gt;400 µm. In addition, the average percentage removal of ES 0.7 mm was 77.24 % for the size of MPs &lt;400 µm and 95.77% for the size of Mps &gt;400 µm. Gaining insight into the mechanisms involved in removing microplastics from drinking water is essential for developing more effective techniques for eliminating them.

Fabrication of rapid sand filter for water treatment using sand and activated carbon

It is pertinent to provide safe drinking water to the people as quality of water keeps deteriorating. According to World Health Organization (WHO), water and hygiene are the primary drivers of public health. Filtration is a water treatment process used for removal of microorganisms and colloidal matters from raw water, therefore this study aims at comparing the effects of sand and activated carbon when used separately in rapid sand filters for water treatment. Fabrication of two models of the rapid sand filters were carried out with 1.2mm stainless steel plates. One of the filters was loaded with gravel (grain size 5mm) at the bottom and this was followed by coarse sand (grain size 3mm) and fine sand (grain size 1mm) at the top. The second filter was loaded with gravel at the bottom and this was followed by coarse sand, fine sand and capped with activated carbon. Raw water, obtained from borehole was stored in a tank and made to pass through each of these filters independently. Sample of the raw water was collected for laboratory analysis in addition to samples of the treated water from each of the two rapid sand filters. The outcomes of the tests reveal that the filtration processes had positive impact on the raw water but the filter capped with activated carbon produced better quality water. The use of activated carbon as the topmost material in a rapid sand filter is recommended as it enhances the quality of treated water in parameters such as colour, conductivity, chloride, hardness, sulphate, total dissolved solids, sodium, magnesium, iron and total plate count. The rapid sand filters would afterwards be used for students’ practical to explain filtration as a water treatment process.

Embedding Fe(0) electrocoagulation in a biologically active As(III) oxidising filter bed

Long-term consumption of groundwater containing elevated levels of arsenic (As) can have severe health consequences, including cancer. To effectively remove As, conventional treatment technologies require expensive chemical oxidants to oxidise neutral arsenite (As(III)) in groundwater to negatively charged arsenate (As(V)), which is more easily removed. Rapid sand filter beds used in conventional aeration-filtration to treat anaerobic groundwater can naturally oxidise As(III) through biological processes but require an additional step to remove the generated As(V), adding complexity and cost. This study introduces a novel approach where As(V), produced through biological As(III) oxidation in a sand filter, is effectively removed within the same filter by embedding and operating an iron electrocoagulation (FeEC) system inside the filter. Operating FeEC within the biological filter achieved higher As(III) removal (81 %) compared to operating FeEC in the filter supernatant (67 %). This performance was similar to an analogous embedded-FeEC system treating As(V)-contaminated water (85 %), confirming the benefits of incorporating FeEC in a biological bed for comparable As(III) and As(V) removal. However, operating FeEC in the sand matrix consumed more energy (14 Wh/m3) compared to FeEC operated in a water matrix (7 Wh/m3). The efficiency of As removal increased and energy requirements decreased in such embedded-FeEC systems by deep-bed infiltration of Fe(III)-precipitates, which can be controlled by adjusting flow rate and pH. This study is one of the first to demonstrate the feasibility of embedding FeEC systems in sand filters for groundwater arsenic removal. Such systems capitalise on biological As(III) oxidation in aeration-filtration, effectively eliminating As(V) within the same setup without the need for chemicals or major modifications.

Field Approach on the Effectiveness of Hydraulic Flocculator Followed By Sedimentation and Rapid Sand Filter

This research investigates the effectiveness of a hydraulic flocculator at the Kalanki Groundwater Treatment Project-Sipradi in Kalanki-Kathmandu. Hydraulic flocculation is a cost-effective alternative to mechanical flocculation, particularly beneficial for developing nations. The study involved determining the optimal Poly Aluminium Chloride (PACl) dosage through Jar Testing and assessing the flocculator's efficiency in the field with this dose. The research also analyzed other treatment units under various PACl doses to evaluate the Water Treatment Plant's operational conditions and the required PACl dose for efficient turbidity removal. The system included components like a deep well source, V-Notch weir tank, hydraulic flocculator, sedimentation tank, rapid sand filter (RSF), chlorinator, and clear water reservoir, with a 16-minute flocculator detention time. Baffle walls were strategically positioned at various intervals on-site. The study revealed that while sedimentation with coagulation achieved peak efficiency at a PACl dose of 80mg/l, it was less efficient than a 16-minute jar detention, likely due to sedimentation tank short-circuiting. Increasing the PACl dose from 20 mg/l to 80 mg/l improved overall unit efficiency, indicating the need for more mixing energy in the existing flocculator length for optimal results. The filter unit's efficiency remained consistent, whether with or without coagulation, at 57.69% and 54.10%, respectively. These results emphasize the importance of further investigation to enhance water treatment processes and coagulant dosages for improved effectiveness in this critical field.

Efficient chemical and microbial removal of iron and manganese in a rapid sand filter and impact of regular backwash

Aeration followed by rapid sand filtration is a common method in drinking water treatment to remove iron (Fe) and manganese (Mn) from anoxic groundwater. To ensure the successful removal of Fe and Mn within a single filter, several factors such as raw water characteristics, backwash procedures and chemical and microbial interactions with the filter medium need to be considered. Here, we assess the characteristics of a single medium rapid sand filter with highly efficient removal of Fe and Mn. Using synchrotron X-ray spectroscopy, we show that formation of ferrihydrite-type Fe oxides in the top of the filter (0–50 cm) accounts for >95 % of the removal of dissolved Fe2+ in the filter. Birnessite-type Mn- oxides, which are thought to be biogenic, form over a wider depth interval (0–110 cm). Results of 16S rRNA gene amplicon sequencing indicate a corresponding distinct vertical stratification of the microbial community, with potential iron-oxidizing Gallionella, Leptothrix and Sideroxydans dominating in the upper part of the filter, and nitrifiers being more prevalent deeper in the filter. Besides Fe and Mn-oxide, Fe-flocs and bacteriological hollow sheets form in the upper part of the filter. Both the Fe-flocs, hollow Fe-sheets and part of the Fe and Mn coatings are removed through backwashing, thereby reducing the pressure difference measured over the filter medium linked to clogging of pores (from 14 kPa to 1.5 kPa) and ensuring continued water flow. Backwashing removes part of the Gallionella, but this does not negatively impact the filter performance. Strikingly, SEM imaging with EDS mapping revealed alternating layers of Fe and Mn-oxides on the coated grains throughout the filter. This indicates slow mixing of the filter medium between the upper 30 cm and the rest of the filter during backwashing. Slow mixing likely contributes to continued success of the filter by ensuring homogeneous filter bed growth, while still allowing for stratification of the microbial community.

Microbial community analysis of sand filters used to treat mine water from a closed uranium mine.

Rapid sand filters (RSFs) are employed in a drinking water treatment to remove undesirable elements such as suspended solids and dissolved metal ions. At a closed uranium (U) mine site, two sets of tandemly linked paired RSF systems (RSF1-RSF2 and RSF1-RSF3) were utilized to remove iron and manganese from mine water. In this study, a 16S rRNA-based amplicon sequencing survey was conducted to investigate the core microbes within the RSF system treating the mine water. In RSF1, two operational taxonomic units (OTUs) related to methanotrophic bacteria, Methylobacter tundripaludum (relative abundance: 18.1%) and Methylovulum psychrotolerans (11.5%), were the most and second most dominant species, respectively, alongside iron-oxidizing bacteria. The presence of these OUTs in RSF1 can be attributed to the microbial community in the inlet mine water, as the three most abundant OTUs in the mine water also dominated RSF1. Conversely, in both RSF2 and RSF3, Nevskia sp., previously isolated from the Ytterby mine manganese oxide producing ecosystem, became dominant, although known manganese-oxidizing bacterial OTUs were not detected. In contrast, a unique OTU related to Rhodanobacter sp. was the third most abundant (8.0%) in RSF1, possibly due to selective pressure from the radionuclide-contaminated environment during RSF operation, as this genus is known to be abundant at nuclear legacy waste sites. Understanding the key bacterial taxa in RSF system for mine water treatment could enhance the effectiveness of RSF processes in treating mine water from closed U mines.

Examination of the Efficiency of Fabric Filter Media in Two-Stage Crossflow Pre-Filtration of Turbid Surface Water Using the Davies Flow Equation

Clogging of rapid sand filters during heavy rainfall causes surface water treatment plants to stop their operations until the river water turbidity decreases to a level that the rapid sand filter is capable of filtering. As clogging of rapid sand filters is impediment in surface water treatment, two-stage crossflow pre-filtration with fabric filter media (linen, crepe-backed satin, burlap, and cotton) was considered in a previous study by Davis and Ekwue (2020) as a possible solution. Pre-filtration with linen fabric filter medium was found to be the most efficient at retaining particles. The present paper incorporated properties of various fabrics previously measured and identified by Davis and Ekwue (2020) with the aim of identifying ideal fabric properties that were effective in removing particles from turbid water. Mechanisms of filtration (surface straining, depth filtration and cake filtration) depicted by each selected fabric during two-stage crossflow pre-filtration were identified and compared to the operation of standard filter media (absorbent, adsorbent, biological and woven). The Davies equation was used to calculate the flow of water through single layer and four layers of fabric filter media. Results indicate that no one specific fabric property could be used to proclaim a fabric as the ideal filter media, but rather all properties of the various fabric contribute to their performance during filtration.Linen fabric was once again determined as the fabric type most efficacious at retaining particles during two-stage crossflow pre-filtration of turbid river water and is therefore recommended.

Analysis of Decision Making on Wastewater Use Technology in the Universitas Pertamina Area

Wastewater available through the sewerage system can be reused as a daily need. With a sewer system, the Universitas Pertamina Area can utilize water according to Government Regulation of the Republic of Indonesia Number 82 of 2001 Class 4. Reuse of wastewater within this scope can improve sustainable development goals. This study aims to analyze the decision-making of sewerage water treatment so that it can be reused according to the class 4 quality standard. The first alternative consists of a collection tank, bar screen, pre-sedimentation, rapid sand filter (RSF), and disinfection. The second alternative consists of a collection tank, bar screen, horizontal roughing filter (HRF), RSF, and disinfection. The two alternatives provided have met the required quality standards. However, the area of land required in alternative one is too large compared to the second alternative. This causes the second alternative to be more appropriate to be applied in the Universitas Pertamina Area. Analysis of decision-making on the use of RSF media is carried out using the Analytical Hierarchy Process (AHP). The alternative media for RSF are sand, granular active carbon (GAC), and zeolite. The criteria for BOD removal, total coliform removal, cost, headloss, and replacement period of the most appropriate zeolite media for use in the RSF unit process.

Study of Flow Rate Effect on Horizontal Flow Concrete Sand Filter Filtration Performance

The need for clean water during the pandemic is significantly increasing due to high public awareness of adopting a clean and healthy lifestyle (PHBS), necessitating more water treatment. Conventional methods are used for water treatment, including coagulation-flocculation system, rapid sand filter, and disinfection. However, these methods have limitations such as reduced capacity and sand filter efficiency, leading to increased backwash costs due to the need for sand replacement caused by particle stratification. In response to these challenges, an innovative method to water treatment is the use of concrete sand filter (CSF). Previous studies predominantly focused on downflow filtration, but there has been limited analysis of horizontal flow. Therefore, this study aimed to assess filtration and backwash effectiveness of CSF with horizontal flow, specifically focusing on the capacity performance in treating water with varying levels of turbidity. Filtration experiment was carried out using simulated water at turbidity of 125 NTU based on the Mataram Channel Turbidity with variations of 0.2, 0.5, 1.0, 5.0, and 10.0 m hour-1, as well as backwash at flow rate of 40.91 m hour-1 for 3 minutes. The variables measured during filtration process included head losses and turbidity at the inlet and outlet of CSF. The results showed that the capacity performance during filtration process was directly proportional to flow rate. Meanwhile, the effectiveness of concrete filter was inversely proportional to flow rate. At initial turbidity &lt;617 NTU, the 3 minutes backwash process obtained lower final turbidity compared to the raw water used, which was 5.19 NTU. Meanwhile, at turbidity 617 NTU, the final turbidity was still high, reaching approximately 14.6–26.4 NTU.

Rapid sand filtration for

The omnipresence of microplastics (MPs) in potable water has become a major concern due to their potential disruptive effect on human health. Therefore, the effective removal of MPs in drinking water is essential for life preservation. In this study, tap water containing microplastic <10 μm in size was treated using constructed pilot-scale rapid sand filtration (RSF) system to investigate the removal efficiency and the mechanisms involved. The results show that the RSF provides significant capacity for the removal and immobilization of MPs < 10 μm diameter (achieving 98 %). Results showed that silicate sand reacted with MPs through a cooperative assembly process, which mainly involved interception, trapping, entanglement, and adsorption. The MPs were quantified by Flow cytometry instrument. A kinetics study underlined the pivotal role of physio-chemisorption in the removal process. MP particles smaller than absorbents, saturation of adsorbents, and reactor hydrodynamics were identified as limiting factors, which were alleviated by backwashing. Backwashing promoted the desorption of up to 97 % MPs, conducive for adsorbent active site regeneration. These findings revealed the critical role of RSF and the importance of backwashing in removing MPs. Understanding the mechanisms involved in removing microplastics from drinking water is crucial in developing more efficient strategies to eliminate them.