Evaluating configuration of dual unit ceramic filter for arsenic removal from highly contaminated groundwater.

Iron (Fe) amended dual unit ceramic filters (DUCF) can be a viable treatment option for arsenic (As) removal from highly contaminated groundwater. The present field study investigated the effect of filter configurations, the separate-unit dual filter (SUDF) and connect-unit dual filter (CUDF), on As removal from groundwater having As concentration of 475 µg/L. SUDF was configured by placing 1st and 2nd filter units side-by-side, whereas the 1st filter unit was placed on the top of the 2nd filter unit in CUDF configuration. Comparing the two filter configurations, SUDF achieving As concentration in the effluent below 50 µg/L (standard value) was found more effective due to sufficient Fe2+ in the 2nd filter. Average As concentrations in the final product (effluent of 2nd filter) were 43 µg/L from SUDF and 111 µg/L from CUDF. The short hydraulic residence time (3.3 min) in the 2nd filter of CUDF, along with limited contact between water and the iron net, lead to inadequate soluble Fe2+ resulting in poor As removal. Both filter configurations effectively removed Fe, P, and Mn with more than 90% reduction of these parameters by the 1st filter. Analysis of insoluble hydrous ferric oxides flocs through XAFS L3-edge spectra confirmed the oxidation of As(III) to As(V) in both the SUDF and CUDF systems resulting in enhanced As removal efficiency. The study results found SUDF as an appropriate configuration for filter design to treat highly contaminated groundwater in rural areas of developing countries.

Chitosan Coagulation Pretreatment to Enhance Ceramic Water Filtration for Household Water Treatment.

Viruses are major contributors to the annual 1.3 million deaths associated with the global burden of diarrheal disease morbidity and mortality. While household-level water treatment technologies reduce diarrheal illness, the majority of filtration technologies are ineffective in removing viruses due to their small size relative to filter pore size. In order to meet the WHO health-based tolerable risk target of 10-6 Disability Adjusted Life Years per person per year, a drinking water filter must achieve a 5 Log10 virus reduction. Ceramic pot water filters manufactured in developing countries typically achieve less than 1 Log10 virus reductions. In order to overcome the shortfall in virus removal efficiency in household water treatment filtration, we (1) evaluated the capacity of chitosan acetate and chitosan lactate, as a cationic coagulant pretreatment combined with ceramic water filtration to remove lab cultured and sewage derived viruses and bacteria in drinking waters, (2) optimized treatment conditions in waters of varying quality and (3) evaluated long-term continuous treatment over a 10-week experiment in surface waters. For each test condition, bacteria and virus concentrations were enumerated by culture methods for influent, controls, and treated effluent after chitosan pretreatment and ceramic water filtration. A > 5 Log10 reduction was achieved in treated effluent for E.coli, C. perfringens, sewage derived E. coli and total coliforms, MS2 coliphage, Qß coliphage, ΦX174 coliphage, and sewage derived F+ and somatic coliphages.

Effect of pre-aeration on the removal of arsenic and iron from natural groundwater in household based ceramic filters.

Maintenance of existing household arsenic (As) removal technologies are comparatively difficult due to the use of the sand beds as a filter. Moreover, pre-aeration of groundwater is avoided during filter operation that may affect the removal efficiency. This study investigated the effect of pre-aeration on the efficacy of simple iron nested ceramic filter (CF) for the removal of As and Fe from the natural groundwater. Five CFs at 5 households in the Bagerhat district of Bangladesh were tested for 31 days with pre-aerated groundwater (AGW system) and non-aerated groundwater (NAGW system). Pe-aeration of groundwater significantly improved (p > 0.5) the removal efficiency of As and Fe in the CFs. The filters effectively removed As in the groundwater from 203 - 231 µg/L to 29-40 µg/L in the AGW system whereas the effluent As were >50 µg/L in the NAGW system. Iron (Fe) was also removed effectively and the overall As and Fe removal efficiency were more than 82% and 99%, respectively in the AGW system. Removal of Mn and PO4-P were significantly enhanced achieving more than 56% and 99% removal, respectively in the AGW system. X-ray absorption fine structure (XAFS) analysis indicated that the oxidation of Fe2+ and As(III) and subsequent adoption/precipitation are the main processes controlling the removals of As and Fe in the CFs. Two stages oxidation of Fe2+ and As(III) in the AGW system facilitated to increase As and Fe removal efficiency. The findings of this study suggest that the iron net nested ceramic filters with pre-aeration step is an effective method and can be employed at the household level in As contaminated region.

Ceramic Scaffolds in a Vacuum Suction Handle for Intraoperative Stromal Cell Enrichment.

During total joint replacement, high concentrations of mesenchymal stromal cells (MSCs) are released at the implantation site. They can be found in cell-tissue composites (CTC) that are regularly removed by surgical suction. A surgical vacuum suction handle was filled with bone substitute granules, acting as a filter allowing us to harvest CTC. The purpose of this study was to investigate the osteopromotive potential of CTC trapped in the bone substitute filter material during surgical suction. In the course of 10 elective total hip and knee replacement surgeries, ß-tricalcium-phosphate (TCP) and cancellous allograft (Allo) were enriched with CTC by vacuum suction. Mononuclear cells (MNC) were isolated from the CTC and investigated towards cell proliferation and colony forming unit (CFU) formation. Furthermore, MSC surface markers, trilineage differentiation potential and the presence of defined cytokines were examined. Comparable amounts of MNC and CFUs were detected in both CTCs and characterized as MSC‱ of MNC with 9.8 ± 10.7‱ for the TCP and 12.8 ± 10.2‱ for the Allo (p = 0.550). CTCs in both filter materials contain cytokines for stimulation of cell proliferation and differentiation (EGF, PDGF-AA, angiogenin, osteopontin). CTC trapped in synthetic (TCP) and natural (Allo) bone substitute filters during surgical suction in the course of a joint replacement procedure include relevant numbers of MSCs and cytokines qualified for bone regeneration.

Alternative Electrode Materials and Ceramic Filter Minimize Disinfection Byproducts in Point-of-Use Electrochemical Water Treatment.

Effects of various electrodes and prefiltration to minimize disinfection byproducts (DBPs) in electrochemical water disinfection was evaluated. The target microorganism, Escherichia coli O157:H7, was effectively inactivated even applying a solar-charged storage battery for the electrolysis process. Extent of microbial inactivation decreased with lower water temperature and higher pH in the free chlorine disinfection system. The RuO2/Ti electrode was most efficient because it produced the lowest concentration of chlorate and the highest generation of free chlorine. Prefiltration using a ceramic filter inhibited formation of halogenated DBPs because it removed precursors of DBPs. For safe point-of-use water treatment, the use of a hybrid prefiltration stage with the electrolysis system is strongly recommended to reduce risks from DBPs. The system is particularly suited to use in developing regions.

Optimization of preparation parameters of ceramic pot water filters for potential application of microbial and fluoride removal from groundwater.

The need to make clean water accessible and affordable for low-income countries is crucial. This study examines the suitability of various clays for Ceramic Pot Water Filters production and groundwater treatment for effective microbe and fluoride removal. For this study, three clays were collected from different geographical locations in Ethiopia,i.e., Hosaenna Clay, Babawuha Clay, and Leku Clay. Organic additives such as sawdust and eragrostis tef husks were used to increase the porosity of the Ceramic Pot Water Filters. The Atterberg limit and particle size distribution tests revealed that BC and HC have moderate to high plasticity and mouldability, making them suitable for CPWF production. The clay chemical composition, phase analysis, and thermal properties were determined using XRF, XRD, and TGA/DTA. The turbidity, fluoride level, total dissolved solids, and pH of the groundwater decreases, from 13 to 0.45 NTU, from 3.4 to 0.053 mg/100 mL, from 1245 to 360 mg/l, and from 8.4 to 7.3, respectively; all of which are within the acceptable range of WHO drinking water standards. Microbial removal tests show that the CPWFs removed 99.3%-100% of total coliform bacteria and 98.48%-100% of fecal coliform bacteria from groundwater. Therefore, this work paves the way to fabricate a clay-based ceramic water filter for low-income countries to provide affordable household groundwater treatment technology for microbial and excess fluoride removal.

A novel sinusoidal design for an electrocoagulation reactor followed by an electro-Fenton reaction and a porous ceramic filter for the treatment of polluted waters.

In this research work, a novel design of an electro-Fenton reactor for the treatment of polluted water was investigated. In addition to the reactor with iron electrodes, a ceramic filter was also used. An electrical circuit was designed to change the cathodes and anodes every 24 s via an electrical relay between the electrodes. The untreated water was sucked into the reactor with an air pump and entered the electrocoagulation chamber after filtration with a ceramic filter. Then, it flows to the polyethylene filter to separate the coagulated particles from the fresh water. To produce 12 L of clean water, the system consumed 100 W of energy. Analysis of a river sample showed a reduction in nephelometric turbidity units (NTUs), total suspended solids (TSS), biochemical oxygen demand (BOD), and chemical oxygen demand (COD). Turbidity reduction studies have shown that the system can improve water transparency by 95%, thereby improving water quality to acceptable levels. Further, this system reduced TSS by more than 86%. In addition, BOD was reduced by more than 84% and COD by more than 88%, as shown by the change in the ratio of BOD to COD from 0.44 to 0.625, indicating improved water quality. According to the results, the treatment system can clean polluted waters, particularly during floods and when industries discharge their effluents into rivers.

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 2 mg/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 3 mg/L or Si concentrations required less than 35 mg/L to effectively reduce As (III) to below the MCL at 5 mg/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 2 mg/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.

A Nanostructured Protein Filtration Device for Possible Use in the Treatment of Alzheimer's Disease-Concept and Feasibility after In Vivo Tests.

BACKGROUND: Alzheimer's disease (AD), along with other neurodegenerative disorders, remains a challenge for clinicians, mainly because of the incomplete knowledge surrounding its etiology and inefficient therapeutic options. Considering the central role of amyloid beta (Aß) in the onset and evolution of AD, Aß-targeted therapies are among the most promising research directions. In the context of decreased Aß elimination from the central nervous system in the AD patient, the authors propose a novel therapeutic approach based on the "Cerebrospinal Fluid Sink Therapeutic Strategy" presented in previous works. This article aims to demonstrate the laborious process of the development and testing of an effective nanoporous ceramic filter, which is the main component of an experimental device capable of filtrating Aß from the cerebrospinal fluid in an AD mouse model. METHODS: First, the authors present the main steps needed to create a functional filtrating nanoporous ceramic filter, which represents the central part of the experimental filtration device. This process included synthesis, functionalization, and quality control of the functionalization, which were performed via various spectroscopy methods and thermal analysis, selectivity measurements, and a biocompatibility assessment. Subsequently, the prototype was implanted in APP/PS1 mice for four weeks, then removed, and the nanoporous ceramic filter was tested for its filtration capacity and potential structural damages. RESULTS: In applying the multi-step protocol, the authors developed a functional Aß-selective filtration nanoporous ceramic filter that was used within the prototype. All animal models survived the implantation procedure and had no significant adverse effects during the 4-week trial period. Post-treatment analysis of the nanoporous ceramic filter showed significant protein loading, but no complete clogging of the pores. CONCLUSIONS: We demonstrated that a nanoporous ceramic filter-based system that filtrates Aß from the cerebrospinal fluid is a feasible and safe treatment modality in the AD mouse model. The presented prototype has a functional lifespan of around four weeks, highlighting the need to develop advanced nanoporous ceramic filters with anti-biofouling properties to ensure the long-term action of this therapy.

Occurrence and point-of-use treatment of contaminants of emerging concern in groundwater of the Nzoia River basin, Kenya.

Groundwater constitutes a major source of fresh water globally. However, it faces serious quality challenges from both conventional pollutants and contaminants of emerging concern (CECs) such as pharmaceutically active compounds (PhACs), personal care products (PCPs) and pesticides. There exists a significant knowledge gap regarding the occurrence of CECs in groundwater, especially in Africa. This study presents unique data on the concentration of fourteen PhACs, five PCPs and nine pesticides in groundwater wells in Nzoia River basin, Kenya. Generally, PCPs were the most dominant class with concentrations up to 10 µg/L (methylparaben). Anti(retro)virals, being important in the treatment of HIV/AIDS, were more prevalent among the PhACs as compared to the developed world, with concentrations up to 700 ng/L (nevirapine). In contrast, pesticides were measured at lower concentrations, the maximum being 42 ng/L (metolachlor). A basic risk assessment shows that - among the detected CECs - carbamazepine may pose medium human health risk and requires further investigation among infants and children. Point-of-use (POU) technologies are being increasingly promoted especially in the developing nations to provide drinking water solutions at the household level, but very little data is available on their performance towards CECs removal. Therefore, besides measuring CECs in groundwater, we investigated ceramic filters and solar disinfection (SODIS) as possible POU treatment options. Both techniques show potential to treat CECs in groundwater, with removal efficiencies higher than 90% obtained for 41 and 22 compounds in ceramic filters and SODIS, respectively. Moreover, for the more recalcitrant compounds (e.g. sulfadoxin), the performance is improved by up to three orders of magnitude when using TiO2 as a photocatalyst in SODIS.

Heavy metal ions and particulate pollutants can be effectively removed by a gravity-driven ceramic foam filter optimized by carbon nanotube implantation.

It is of great significance to develop a new gravity-driven filter to remove water pollutants, but it is still challenging. Here, a novel and simple strategy is demonstrated to manufacture fly ash (FA) ceramic foams showing a three-dimensional interconnected porous structure, with multiwalled carbon nanotubes (MWCNTs) implanted by combining carbamate grafting and polydimethylsiloxane coating. The polydimethylsiloxane formed a physical coating on the carbamate group, generating an effective thermal insulating layer on the outer side of the entire MWCNT. The FA foam, which shows a sufficient adsorption capacity for Pb(II) (51.67 ± 1.17 mg g-1) and Cd(II) (30.12 ± 0.37 mg g-1) at pH = 5, T = 25 °C, has a 96.33%, 95.12%, 89.50% removal efficiency for Cd(II), Pb(II), and particulate pollutants, and exhibits excellent recycling performance. This paper provides new opportunities to fabricate gravity-driven filters with low energy consumption for wastewater treatment.

Removal of arsenic from water through ceramic filter modified by nano-CeO2: A cost-effective approach for remote areas.

The groundwater with high arsenic concentration is widespread, especially in many remote areas of developing countries. Arsenic existing in drinking water sources has a high risk to human health. In this study, an innovative effort to remove As(V) from water using ceramic filters functionalized with CeO2 nanocomposites (CF-CeO2) was investigated. Considering removal efficiency and flow rate, the suitable coating amount of CeO2 was determined for the production of CF-CeO2. Based on the factorial analysis, influent arsenic concentration and pH were found to be significant factors in As(V) removal. Furthermore, CF-CeO2 exhibited a good removal capability over a wide pH range and was insensitive to the change of background electrolyte concentration. In the treatment of natural water, the existence of medium and low turbidity levels facilitated As(V) removing, while the high turbidity level exhibited the opposite effect. Based on macroscopic experiments and microscopic characterizations, it was revealed that the As(V) removal mechanism by the CF-CeO2 mainly included ion-exchange and electrostatic attraction. The findings in this study provided convincing evidence for the use of CF-CeO2 as a high-efficiency, low-cost, and safe approach for water purification in the remote areas of developing countries.

Sustainable nano-sodium silicate and silver nitrate impregnated locally made ceramic filters for point-of-use water treatments in sub-Sahara African households.

The poor access to water quality for Nigerians has pushed for the designing of new trend silver nitrate impregnated locally made Point-Of-Use (POU) ceramic filters to enhance water purification efficiency for household use. This study utilized silver nitrate-molded ceramic filters prepared with Kaolin from Owode, silt soil, sodium silicate, sawdust, and distilled water in three varying proportions to ascertain pollution removal efficiencies. Heating was carried out by firing the filters at 900 °C and further preheating at 400 °C after dipping in silver nitrate solution. Silver nanoparticle and dissociated particle discharge from filter pot painted with 0.03 mg/g casein-covered nAg or AgNO3 were estimated as an element of pH (5-9), ionic strength (1-50mM), and cation species (Na+, Ca2+, Mg2+). Silver delivery was constrained by disintegration as Ag+ and resulting cation exchange measures, paying little heed to silver structure applied. Water analysis for both heavy metals (Pb and Cd) and microbial load (E. coli) evaluated, corroborate the maximum removal efficiency. It was observed that kaolin-sawdust with the Silver nitrate filters showed a constant and effective removal of both heavy metals and disinfection of microbial loads. The minimum flow rates observed were 4.97 mL/min for batch filter used for Iju River water sample one (AF1) and 4.98 mL/min for batch filter used for Iju River water sample two (AF2) having porosity 49.05% and 50.00%, whereas the 5 mL/min higher flow rate was used for batch filter from borehole water sample one (BF1) and batch filter used for well water sample two (CF2) with porosity of 50.00%. Significantly, the results obtained show that the filters are suitable for point-of-use application in both the urban and rural areas of developing countries such as Nigeria.

Detection of Free-Living Amoebae and Their Intracellular Bacteria in Borehole Water before and after a Ceramic Pot Filter Point-of-Use Intervention in Rural Communities in South Africa.

Free-living amoebae (FLA) are ubiquitous in nature, whereas amoeba-resistant bacteria (ARB) have evolved virulent mechanisms that allow them to resist FLA digestion mechanisms and survive inside the amoeba during hostile environmental conditions. This study assessed the prevalence of FLA and ARB species in borehole water before and after a ceramic point-of-use intervention in rural households. A total of 529 water samples were collected over a five-month period from 82 households. All water samples were subjected to amoebal enrichment, bacterial isolation on selective media, and molecular identification using 16S PCR/sequencing to determine ARB species and 18S rRNA PCR/sequencing to determine FLA species present in the water samples before and after the ceramic pot intervention. Several FLA species including Acanthamoeba spp. and Mycobacterium spp. were isolated. The ceramic pot filter removed many of these microorganisms from the borehole water. However, design flaws could have been responsible for some FLA and ARB detected in the filtered water. FLA and their associated ARB are ubiquitous in borehole water, and some of these species might be potentially harmful and a health risk to vulnerable individuals. There is a need to do more investigations into the health risk of these organisms after point-of-use treatment.

Evaluation of consistent use, barriers to use, and microbiological effectiveness of three prototype household water treatment technologies in Haiti, Kenya, and Nicaragua.

Household water treatment (HWT) can improve drinking water quality and reduce diarrheal disease. New HWT technologies are typically evaluated under ideal conditions; however, health gains depend on consistent, effective household use, which is less often evaluated. We conducted four evaluations of three prototype HWT technologies: two filters and one electrochlorinator. Evaluations consisted of a baseline survey, HWT distribution to households (ranging from 60 to 82), and four visits (ranging from 1 week-14 months after distribution). Each visit included a survey, observation of treated water presence (confirmed use), and microbiological analysis of treated and untreated samples for E. coli. Consistent use was defined as the proportion of total visits with confirmed use. Overall, confirmed use declined 2.54% per month on average, and 2-72% of households demonstrated 100% consistent use. Consistent use was positively associated with baseline HWT knowledge and practice and belief that drinking water was unsafe, and negatively associated with technological problems. Reported barriers to use were behavioral, such as forgetting or when outside the home, and technological failures. Technologies demonstrated 68-96% E. coli reductions, with 18-70% of treated samples having detectable E. coli. Results highlight the importance of household use evaluations within prototype HWT technology design cycles, the need for standard evaluation metrics, and difficulties in achieving both consistent use and microbiological effectiveness with HWT technologies.

A new route to the stable capture and final immobilization of radioactive cesium.

Radioactive Cs released from damaged fuel materials in the event of nuclear accidents must be controlled to prevent the spreading of hazardous Cs into the environment. This study describes a simple and novel process to safely manage Cs gas by capturing it within ceramic filters and converting it into monolithic waste forms. The results of Cs trapping tests showed that CsAlSiO4 was a reaction product of gas-solid reactions between Cs gas and our ceramic filters. Monolithic waste forms were readily prepared from the Cs-trapping filters by the addition of a glass frit followed by thermal treatment at 1000°C for 3h. Major findings revealed that the Cs-trapping filters could be added up to 50wt% to form durable monoliths. In 30-50wt% of waste fraction, CsAlSiO4 was completely converted to pollucite (CsAlSi2O6), which is a potential phase for radioactive Cs due to its excellent thermal and chemical stability. A static leaching test for 28 d confirmed the excellent chemical resistance of the pollucite structure, with a Cs leaching rate as low as 7.21×10-5gm-2/d. This simple scheme of waste processing promises a new route for radioactive Cs immobilization by synthesizing pollucite-based monoliths.

SERS substrates fabricated using ceramic filters for the detection of bacteria: Eliminating the citrate interference.

It was found that spectra obtained for bacteria on SERS substrates fabricated by filtering citrate-generated Ag nanoparticles (NPs) onto rigid, ceramic filters exhibited peaks due to citrate as well as the bacteria. In many cases the citrate spectrum overwhelmed that of the bacteria. Given the simplicity of the method to prepare these substrates, means of eliminating this citrate interference were explored. It was found that allowing a mixture of bacteria suspension and citrate-generated Ag NPs to incubate prior to filtering onto the ceramic filter eliminated this interference.

SERS substrates fabricated using ceramic filters for the detection of bacteria.

SERS substrates were fabricated by filtering either Ag or Au colloidal particles onto rigid, ceramic filters - onto which suspensions of bacteria were then filtered. SERS spectra of the bacteria were obtained using a Raman spectrometer that has an 'orbital raster scan' capability. It was shown that bacteria samples prepared in this manner were uniformly distributed onto the surface of the SERS substrate. The effect of common buffer systems on the SERS spectra was investigated and the utility of using the SERS technique for speciation of bacteria was explored.

Long-term evaluation of the performance of four point-of-use water filters.

Despite technological advances water supply quality and poor access to safe water remain a major problem in developing countries, especially in rural areas. Point-of-use (POU) water treatment has been shown to be a viable option to produce safe drinking water quality. The aim of this study was to evaluate, under laboratory conditions over 14 months, the performance of four household filtration systems: membrane filter (MF), one-candle ceramic filter (1CCF), two-candle ceramic filter (2CCF) and pot ceramic filter (PCF). The evaluation was made using spiked water having the required concentrations of turbidity, Escherichia coli and Total Dissolved Solids (TDS). The results show that all systems have high removal efficiencies for turbidity (98-99%), and E. coli 4-5 Log Reduction Value (LRV). The poorest efficiency was for TDS (9-18%). The MF and the CCF displayed no significant difference in efficiencies for these parameters. The PCF had less significant differences for turbidity removal than the other systems. The average filtration rate for all systems decreased during the operation time. The CPF showed the major potential to be used in rural communities mainly for its low operational level and maintenance requirements as well as its local craftsmanship. It was observed that the efficiency of the systems is highly sensitive to cleaning and maintenance activities and therefore, the system sustainability will depend considerably on the training and education of the potential users.

Studies on the treatment efficiency of sediment phosphorus with a combined technology of PCFM and submerged macrophytes.

The removal efficiency of sediment phosphorus (P) in all fractions with a combined technology of porous ceramic filter media (PCFM) and submerged macrophytes was studied in Donghu Lake, Wuhan, China. The adsorption kinetic models of the sediment P in all fractions on PCFM could be described well by a power function equations (Qt = k · t(a), 0 < a < 1). The P removal capacity of the combination of PCFM and Potamogeton crispus, a submerged macrophyte, was higher for all P forms than that of the combination of PCFM and another macrophyte, Vallisneria spiralis. This study suggested that the combination of PCFM and macrophytes could achieve a synergetic sediment P removal because the removal rates of the combinations were higher than the sum of that of PCFM and macrophytes used separately. The combined technology could be further applied to treat internal P loading in eutrophic waters.