| 1. |
- Blum, Kristin M., 1989-, et al.
(författare)
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Comprehensive assessment of organic contaminant removal from on-site sewage treatment facility effluent by char-fortified filter beds
- 2019
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Ingår i: Journal of Hazardous Materials. - : Elsevier. - 0304-3894 .- 1873-3336. ; 361, s. 111-122
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The removal of organic contaminants from wastewater using cost-efficient and easily accessible methods have been increasingly studied in recent years. Most studies have focused on municipal sewage treatment plants; however, our study investigated treatment with char-fortified filter beds for on-site sewage treatment facilities (OSSFs). OSSFs are commonly used in rural and semi-urban areas all over the world to treat wastewater to reduce eutrophication and water-related diseases. To screen for a wide range of organic contaminants in order to improve the understanding of wastewater treatment efficiency and molecular properties, samples were taken from an OSSF field study site that used three filter types: sand, char-fortified sand, and char-fortified gas concrete. First, we screened for organic contaminants with state-of-the-art gas chromatography and liquid chromatography mass spectrometry-based targeted and untargeted analysis and then we developed quantitative structure-property relationship models to find the key molecular features responsible for the removal of organic contaminants. We identified 74 compounds, of which 24 were confirmed with reference standards. Amongst these 74 compounds were plasticizers, UV stabilizers, fragrances, pesticides, surfactant and polymer impurities, pharmaceuticals and their metabolites, and many biogenic compounds. Sand filters that are sometimes used as a last treatment step in OSSFs can remove hydrophobic contaminants. The addition of biochar significantly increases the removal of these and a few hydrophilic compounds (Wilcoxon signed-rank test, α = 0.05). Gas concrete did not appear to be suitable for the removal of organic contaminants. This study showed that, besides hydrophobic effects, biodegradation is the most important removal pathway in long-term field applications. However, further improvements are necessary to remove very hydrophilic contaminants as they were not removed with sand and biochar-fortified sand.
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| 2. |
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| 3. |
- De Colle, Mattia, 1989-, et al.
(författare)
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The Use of High-Alloyed EAF Slag for the Neutralization of On-Site Produced Acidic Wastewater: The First Step Towards a Zero-Waste Stainless-Steel Production Process
- 2019
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Ingår i: Applied Sciences. - : MDPI. - 2076-3417. ; 9:19
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Tidskriftsartikel (refereegranskat)abstract
- Recycling of steelmaking slags has well-established applications, such as their use in cement, asphalt, or fertilizer industries. Although in some cases, such as the electric arc furnace (EAF) high-alloyed stainless-steel production, the slag’s high metal content prevents its use in such applications. This forces companies to accumulate it as waste. Using concepts such dematerialization, waste management, industrial symbiosis, and circular economy, the article drafts a conceptual framework on the best route to solving the landfilling issue, aiming at a zero-waste process re-design. An experimental part follows, with an investigation of the use of landfill slag as a substitute of limestone for the neutralization of acidic wastewater, produced by the rinsing of steel after the pickling process. Neutralization of acidic wastewater with both lime and slag samples was performed with two different methods. Two out of four slag samples tested proved their possible use, reaching desired pH values compared to lime neutralizations. Moreover, the clean waters resulting from the neutralizations with the use of both lime and slag were tested. In terms of hazardous element concentrations, neutralization with slag yielded similar results to lime. The results of these trials show that slag is a potential substitute of lime for the neutralization of acidic wastewater.
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| 4. |
- Gustafsson, Jon Petter, et al.
(författare)
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Phosphate removal by mineral-based sorbents used in filters for small-scale wastewater treatment
- 2008
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Ingår i: Water Research. - : Elsevier. - 0043-1354 .- 1879-2448. ; 42:1-2, s. 189-197
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Tidskriftsartikel (refereegranskat)abstract
- The mineral-based sorbents Filtra P, Polonite (R), natural wollastonite and water-cooled blast furnace slag (WCBFS) were studied in terms of their PO4 removal performance. Results from a long-term column experiment showed that both Filtra P and Polonite (R) removed > 95% of PO4 from the applied synthetic solution, and that the used filter materials had accumulated several (1.9-19) g kg(-1) P. Phosphorus was removed also by natural wollastonite and WCBFS, but these materials were less efficient. Batch experiments on the used materials showed that the solubility PO4 was considerably larger than the one expected for crystalline Ca phosphates such as hydroxyapatite, and results from investigations with attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) on the Filtra P material showed that the formed P phase was not crystalline. These evidence suggest that a soluble amorphous tricalcium phosphate (ATCP) was formed in the mineral-based sorbents; the apparent solubility constant on dissolution was estimated to log K-s = -27.94 ( 0.31) at 21 degrees C. However, since only up to 18% of the accumulated PO4 was readily dissolved in the experiments, it cannot be excluded that part of the phosphorus had crystallized to slightly less soluble phases. In conclusion, Filtra P and Polonite are two promising mineral-based sorbents for phosphorus removal, and at least part of the accumulated phosphorus is present in a soluble form, readily available to plants.
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| 5. |
- Hallberg, Magnus, et al.
(författare)
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Evaluation of a sand filter material for road runoff treatment– Pilot-scale field trial focused on copper and zinc removal
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The negative effects of stormwater discharges on receiving aquatic environments and the need for their purification were highlighted by the EU courts' "Weser-Ruling" in May 2020. The ruling stated the need for removal of dissolved pollutants. The decision justifies field studies for development of far-reaching methods for runoff treatment. In this in situ study, a standard sand was used as medium for road runoff filtration and removal of dissolved and particle-bound (< 0.45 µm) zinc (Zn) and copper (Cu), Data collected included 24 road runoff events, mimicking the flow variations and pollutant emissions over a seven-month period. The findings showed that filter sand can be used to remove Zn and Cu from road runoff in a gravity fed treatment system. The removal of total Zn and Cu was 93% and 67%, respectively. Dissolved Zn was efficiently removed by the sand (87%), however not Cu (19%). The sand efficiently removed total suspended solids (TSS) from maximum occurring 443 mg L-1 to below 5 mg L-1. No head loss due to the TSS loadings was observed. The initial studies show the sand's potential to remove the investigated metals, but in the longer term, effluent concentrations may exceed emission permit values.
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| 6. |
- Hallberg, Magnus, et al.
(författare)
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Evaluation of a sand filter material for road runoff treatment- pilot-scale field trial focused on copper and zinc removal
- 2022
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Ingår i: Water practice and technology. - : IWA Publishing. - 1751-231X. ; 17:8, s. 1652-1665
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Tidskriftsartikel (refereegranskat)abstract
- The effects of stormwater discharges on receiving aquatic environments and the need for their purification were highlighted by an EU court in May 2020. The ruling stated the need for removal of dissolved pollutants, which justifies field studies for development of far-reaching methods for runoff treatment. In this study, a standard sand was used as medium for road runoff filtration and removal of dissolved and particle-bound (<0.45 mu m) zinc (Zn) and copper (Cu). Data included 24 road runoff events, mimicking the flow variations and pollutant emissions over a seven-month period. The findings showed that sand can be used to remove Zn and Cu from road runoff in a gravity fed treatment system at a surface load ranging from 16.8 to 201 L m(-2) h(-1). The removal of total Zn and Cu was 93 and 67%, respectively. Dissolved Zn was efficiently removed by the sand (87%), however not Cu (19%). The sand efficiently removed total suspended solids (TSS) from the maximum occurring 443 mg L-1 to below 5 mg L-1. No head loss due to the TSS loadings was observed. The sand's potential to remove the investigated metals was shown, but in the longer term, effluent concentrations may exceed permitted values.
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| 7. |
- Hamisi, Rajabu, et al.
(författare)
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Long-term phosphorus sorption and leaching in sand filters for onsite treatment systems
- 2022
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 833, s. 155254-155254
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Tidskriftsartikel (refereegranskat)abstract
- The sorption capacities of sand filters used for onsite wastewater treatment and their associated risks of phosphorus (P) leaching on contact with rainwater were investigated in column experiments and with modelling tool for over 300 days. Columns packed with sand were exposed to real domestic wastewater of different characteristics and hydraulic loading modes. The wastewater fed into the columns was effluent collected from three different treatment units in the field: a septic tank (ST), biofiltration tank (BF) and Polonite® filter bag (PO). The risk of P leaching to groundwater and surface water was also assessed, by exposing the same sand columns to natural rainwater. Overall results indicated that sand soils can exhibit different adsorption and desorption capacities for electrical conductivity (EC), Total-P, phosphate-P and total suspended solids, depending on the characteristics of influent wastewater, loading rate and total operation time. The removal efficiencies of the sand columns increased in the order ST (98.16 %) > PO (93.36%) > BF (81.57%) for PO4-P and slightly decreased ST (97.11 %) > PO (92.06%) > BF (76.76%) for Total-P columns. All sand columns loaded with actual wastewater solutions from septic tanks and biofiltration tank have demonstrated high risks of phosphorus leaching (> 99.99%) to the groundwater. The modelling was successful captured behavior of EC tracer and adsorption of PO4-P with acceptable prediction uncertainty in the PO < 8% columns. The modelling results indicated that the decrease of loading rate from 83.3 mL d-1 to 20.83 mL d-1 led to an average increase of removal efficiency and prolong operational lifetime and mass of adsorbed Total-P in the sand soil. This study concludes that sand is a valuable filter medium at low loading rate for phosphorus removal in full-scale operations of onsite treatment systems, however very vulnerable for leaching P when in contact with rainwater.
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| 8. |
- Hamisi, Rajabu, et al.
(författare)
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Modelling phosphorus sorption kinetics and the longevity of reactive filter materials used for on-sitewastewater treatment
- 2019
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Ingår i: Water. - : MDPI AG. - 2073-4441. ; 11:4
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Tidskriftsartikel (refereegranskat)abstract
- Use of reactive filter media (RFM) is an emerging technology in small-scale wastewater treatment to improve phosphorus (P) removal and filter material longevity for making this technology sustainable. In this study, long-term sorption kinetics and the spatial dynamics of sorbed P distribution were simulated in replaceable P-filter bags filled with 700 L of reactive material and used in real on-site treatment systems. The input data for model calibration were obtained in laboratory trials with Filtralite P®, Polonite® and Top16. The P concentration breakthrough threshold value was set at an effluent/influent (C/C 0 ) ratio of 1 and simulations were performed with P concentrations varying from 1 to 25 mg L -1 . The simulation results showed that influent P concentration was important for the breakthrough and longevity, and that Polonite performed best, followed by Top16 and Filtralite P. A 100-day break in simulated intermittent flow allowed the materials to recover, which for Polonite involved slight retardation of P saturation. The simulated spatial distribution of P accumulated in the filter bags showed large differences between the filter materials. The modelling insights from this study can be applied in design and operation of on-site treatment systems using reactive filter materials.
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| 9. |
- Hamisi, Rajabu, et al.
(författare)
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Optimization of on-site wastewater treatment efficiency and recovery based on nutrient mobility and adsorption kinetics modelling using HYDRUS-2D coupled with PHREEQC
- 2024
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 492
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Tidskriftsartikel (refereegranskat)abstract
- A closed-loop on-site wastewater treatment system (OWT) was studied comprising steps of septic tank to remove organics (Biological Oxygen Demand (BOD)), biofiltration clarifier for biological removal of nitrogen (N), phosphorus (P) and BOD, reactive Polonite® filter for chemical adsorption and precipitation removal of dissolved P, and tidal flow constructed wetland (TFCW) sand filter for polishing the effluent to low P and N effluent Swedish standards. The field experimental data that have been used to optimize TFCW design in the numerical modelling using HYDRUS-2D coupled with and without PHREEQC indicated that the adsorption efficiency of the reactive Polonite® adsorbent was nearly double to that obtained in TFCW sand filters for PO4-P (95 %) and Total-P (85 %) removal in summer at a high temperature range (15.4–18.8 °C) and pH range (9.9–10.8). The weaker PO4-P (53 %) and Total-P (25 %) removal efficiency in winter was due to a low temperature (1.5–8.1 °C) and low pH (7.2–7.9). This decrease in pH was attributed to salinity in the domestic wastewater and dilution of rainwater. Modelling results revealed that the transport mechanisms and rate of P adsorption kinetics in the TFCW sand filters enhanced with calcium and iron flow from chemical dissolution in the preceding Polonite® adsorbent was increased with the increase in temperature. However, the P adsorption was less sensitive at high ferrihydrite (Fe(OH)3) dose, suggesting limited effects of cations dissolution and abundance of metal oxides and hydroxide ions at the mineral surface for anions exchange with phosphate for surface complexation. The strategy of combining field data and modelling provided valuable insights for assessing adaptability and optimizing TFCW design under variable fluxes and scenario effects of insulated/uninsulated and dilution by rainwater in cold-climate regions.
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| 10. |
- Hamisi, Rajabu, et al.
(författare)
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Performance of a tidal flow constructed wetland used for post-treatment of on-site wastewater in cold climate
- 2022
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Ingår i: Journal of Water Process Engineering. - : Elsevier BV. - 2214-7144. ; 47
-
Tidskriftsartikel (refereegranskat)abstract
- The performance of a tidal flow constructed wetland (TFCW) following wastewater treatment in a package plant designed for two households was studied in a nine-month field trial and its design evaluated through process modelling and pumping tests. The TFCW is operated by filling and draining periods lasting five to nine days, depending on wastewater production by users. The effects of passive aeration, temperature, influent concentration of nutrients and bacteria as well as hydraulic loading on the treatment efficacy of the TFCW system were studied. Results showed that the TFCW system removed ammonium-nitrogen (NH4-N, 76%), phosphate -phosphorus (PO4-P, 56%), total inorganic nitrogen (TIN, 28%) and reduced water pH by15%. The removal efficiency of TIN was significantly improved in the summer (> 50%). The average influent concentration of total phosphorus (TP) was low after the preceding package plant treatment (1.12 mg L-1), but the TFCW showed ability to further reduce TP to the average concentration of 0.57 mg L-1. A coupled reactive transport model was developed in the COMSOL Multiphysics (R) 5.6 software to predict processes of water flow and was validated against the actual data from the field. The modelling exhibited a satisfactory prediction accuracy and capability to capture behavior of effluent PO4-P, NH4-N and dissolved oxygen concentration. Moreover, modelling processes helped to understand the defects of water flow and adsorption processes within the treatment wetland.
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| 11. |
- Hamisi, Rajabu, et al.
(författare)
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Performance of an On-Site Wastewater Treatment System Using Reactive Filter Media and a Sequencing Batch Constructed Wetland
- 2019
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Ingår i: Sustainability. - : MDPI. - 2071-1050. ; 11:11
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Tidskriftsartikel (refereegranskat)abstract
- Many on-site wastewater treatment systems, such as soil treatment systems, are not sustainable in terms of purification efficiency, nutrient recycling potential, and economics. In this case study, a sequencing batch constructed wetland (SBCW) was designed and added after a package treatment plant (PTP) using reactive filter media for phosphorus (P) removal and recycling. The treatment performance of the entire system in the start-up phase and its possible applicability in rural areas were investigated. Raw and treated effluents were sampled during a period of 25 weeks and analyzed for nitrogen, phosphorus, BOD7, and bacteria. Field measurements were made of wastewater flow, electrical conductivity, oxygen, and temperature. The entire system removed total-P and total inorganic nitrogen (TIN) by 83% and 22%, respectively. High salt concentration and very low wastewater temperature were possible reasons for these unexpectedly low P and TIN removal efficiencies. In contrast, removal rates of bacteria (Escherichia coli, enterococci) and organic matter (as BOD) were high, due to filtration in the alkaline medium Polonite((R)) (Ecofiltration Nordic AB, Stockholm, Sweden) and the fine sand used as SBCW substrate. High pH in effluent from the PTP was efficiently reduced to below pH 9 in the SBCW, meeting recommendations by environmental authorities in Sweden. We concluded that treating cold on-site wastewater can impair treatment performance and that technical measures are needed to improve SBCW performance.
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| 12. |
- Hamisi, Rajabu, et al.
(författare)
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Phosphorus sorption and leaching in sand filters used for onsite wastewater treatment - a column experiment
-
Recension (refereegranskat)abstract
- The sorption capacities of filter sands used for onsite wastewater treatment and their associated risks of phosphorus (P) leakage on contact with rainwater were investigated in column experiments and modelling studies. Columns packed with sand were exposed to real domestic wastewater of different characteristics and hydraulic loading modes. The wastewater fed into the columns was effluent collected from three different treatment units in the field: a septic tank (ST), biofiltration tank (BF) and Polonite® filter bag (PO). The risk of P leaching to groundwater and surface water was also assessed, by exposing the same sand columns to artificial rainwater. The results indicated that sand columns can exhibit different adsorption capacities for Total-P, phosphate-P and total suspended solids, depending on the characteristics of influent wastewater. The adsorption capacity increased in the order ST > BF > PO, based on availability of organic matter to form biofilm. Effluent from Pol columns was significantly clearer, indicating lower organics content, than effluent from ST and BF columns. The modelled breakthrough curves for Total-P desorption agreed satisfactorily with the measured values, but further model improvement is needed.
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| 13. |
- Hamisi, Rajabu, et al.
(författare)
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Simulating the hydraulic dynamics and treatment performance of a sequencing batch flow constructed wetland
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Recension (refereegranskat)abstract
- In a six-month field trial, the performance of a full-scale sequencing batch flow constructed wetland (SBCW) treating on-site wastewater was determined. The filling and draining periods lasted 5-9 days, depending on wastewater production by users (two households). The results indicated that the SBCW system efficiently removed ammonium-nitrogen (NH4-N, 76%) and Escherichia coli (89%). However, draining by pumping increased preferential water flow and considerably limited removal of dissolved phosphorus (PO4-P) in the filter bed. Analysis of water samples from nine points and three vertical levels of the wetland bed showed that pumping aerated the bed, resulting in removal of NH4-N being highest in the top 0-0.2 m layer (43%) intermediate in the 0.2-0.4 m layer (32%), and lowest in the deep (0.4-0.6 m) layer (4%). Complementary modeling using COMSOL Multiphysics software to predict the hydraulic dynamics for three different SBCW designs indicated that the drainage system of the present SBCW should be re-designed to increase contact time and aeration, for improved phosphorus and nitrogen removal.
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| 14. |
- Hamisi, Rajabu, et al.
(författare)
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Treatment efficiency and recovery in sand filters for on-site wastewater treatment: Column studies and reactive modelling
- 2024
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Ingår i: Journal of Cleaner Production. - : Elsevier Ltd. - 0959-6526 .- 1879-1786. ; 462
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Tidskriftsartikel (refereegranskat)abstract
- This study examined the adsorption capacity and treatment efficiency of sand filters in on-site treatment systems for cold climate regions. The effects of different operating conditions, porosity and kinetics parameters were investigated in column experiments and COMSOL Multiphysics® modelling, to comprehensively reveal the mechanisms and optimize treatment efficiency of nitrogen (N) and phosphorus (P) removal in a field tidal flow constructed wetland (TFCW), treating effluent from a package treatment plant with P filter material. The results from column experiments with sand showed that Total-P adsorption rate was dependent on feed water quality (Septic tank >0.77 ± 0.06 g kg−1; Biotreatment >0.41 ± 0.07 g kg−1; Reactive material Polonite® <0.18 ± 0.07 g kg−1). In the field TFCW trial, Total-P adsorption in the top layer (>1.42 ± 0.55 g kg−1) and middle layer (>1.06 ± 0.51 g kg−1) was twice that in laboratory columns, due to strong interaction with the air-water interface and use of fluctuated domestic wastewater solutions. The breakthrough curve (BTCs) of the coarse sand matched the physical behaviour of tracer electrical conductivity (EC) in effluent from the sand column experiments. The modelling results demonstrated that high filter porosity and low hydraulic load were significant factors for optimal removal of NH4–N, Total-N, PO4–P, Total- P in the top layer (>99.95 ± 0.03 %, 44.37 ± 28.75%, 70.89 ± 28.30%, 76.18 ± 20.3%), middle layer (>98.94 ± 1.77%, 18.23 ± 23.04%, 76.62 ± 28.73%, 65.40 ± 31.85%) and deep layer (>99.99 ± 0.02%, 65.50 ± 20.64%, 75.53 ± 23.16%, 41.54 ± 28.81%) in the TFCW system, respectively. The results show that on-site wastewater treatment in cold climate TFCW can be applied as a technology to polish effluent from a three-step pretreatment system. However, hydraulic optimization is an important factor for the design of the TFCW to receive a successful long-term operating system.
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| 15. |
- Kholoma, Ezekiel, et al.
(författare)
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Filter Media-Packed Bed Reactor Fortification with Biochar to Enhance Wastewater Quality
- 2020
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Ingår i: Applied Sciences. - : MDPI AG. - 2076-3417. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- Contamination of water sources by inappropriately disposed poorly treated wastewater from countryside establishments is a worldwide challenge. This study tested the effectiveness of retrofitting sand (Sa)- and gas-concrete (GC)-packed reactors with biochar
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| 16. |
- Kholoma, Ezekiel, 1972-, et al.
(författare)
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Filter media-packed bed reactor fortification with biochar to enhance wastewater treatment
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Contamination of water bodies with inappropriately released, poorly treated wastewater from rural establishments is a challenge world-wide. Rural communities in developed countries are now required to comply with statutory discharge limits, but less costly alternative technologies by which to comply are scarce. However, it is possible that retrofitting on-site facilities with specialist treatment units could provide a feasible solution. This study tested the effectiveness of retrofitting sand (Sa)- and gas-concrete (GC)-packed down-flow reactors with biochar (BC) in removing turbidity, dissolved organic carbon (DOC), phosphate (PO43-) and total phosphorus (TP) from wastewater. The reactors were each intermittently loaded with 0.063 L/d for 399 days. In general, all reactors achieved <3 NTU effluent turbidity (99% efficiency). The GC reactors were best at removing incoming PO43- (6.1 mg/L) and DOC (25.3 mg/L), trapping >95% and >60%, respectively. Compared with a reference Sa reactor (PO43- removal 35%; DOC removal 52%), the fortified sand (Sa-BC) filter removed significantly more PO43- (>45% removal, p=0.022) and DOC (>58% removal, p=0.034). In regression analysis, 53%, 81% and 85% of PO43- sorption variation in Sa, BC and Sa-BC filters, respectively, was explained by variations in reactor effluent pH. Similarly, a strong linear correlation was found between PO43- sorption efficiency and the pH of fortified (GC-BC, r > 0.7) and reference (r = 0.6) GC filters, suggesting chemisorption mechanisms. Therefore, if only sand is readily available for treating septic tank effluent, fortifying it with biochar could be a possible measure to improve its efficacy.
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| 17. |
- Kholoma, Ezekiel, 1972-
(författare)
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Fortification of soil-based wastewater treatment systems with versatile ubiquitous reactive media for enhanced removal of phosphorus and other pollutants
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Concerns about potential risks posed by discharge from small-scale wastewater treatment (SWT) systems to receiving water bodies have prompted robust enforcement of national discharge quality standards in rural areas of most developed countries. Consequently, communities in such places are in need of effective technologies with which to achieve compliance. Currently, reactive filter (RF) media are increasingly preferred over advanced alternatives, due mainly to their simplicity, affordability and proven potential. However, many of the field-tested filters are commercial products which are costly and scarce but also only capable of removing few contaminants they are engineered to target hence often requiring to be coupled with other treatment units to achieve full treatment. In the preliminary findings of this study, biochar (BC) was identified and thus suggested basing on existing literature, as a versatile ubiquitous low-cost material for treating wastewater. Its effectiveness in fortifying sand (Sa) and gas concrete (GC)-based SWT facilities was later demonstrated in long-term experiments using laboratory packed bed reactors and field constructed filter beds. The efficacy of SaBC and GCBC systems in reducing turbidity (>95%), DOC (60%; p<0.05) and PO43- (40-90%; p<0.05) was significantly higher than for their reference counterparts. Further, sorbed P was more leachable from Sa (11.2 mgkg-1) and SaBC (20.5 mgkg-1) filters but more extractable and hence plant-available in GC (65-91 mgkg-1). Therefore, the study concluded that fortification of soil-based systems with biochar filters may be a promising solution in enhancing performances of soil-based wastewater treatment systems, while P-rich RF media can act as a nutrient source for plants if recycled to agriculture.
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| 18. |
- Kholoma, Ezekiel, 1972-, et al.
(författare)
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Leachability and plant availability of phosphorus in post-sorption wastewater filters fortified with biochar
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Sand and gravel are widely applied in field filter systems for small-scale wastewater treatment. However, alternative filter materials are needed to achieve better treatment performance in removing contaminants and trapping plant nutrients for recycling to agriculture. This study assessed the plant availability and leachability of phosphorus (P) trapped in sand (Sa), biochar (BC) and gas concrete (GC, Sorbulite®) media used previously for phosphorus (P) removal in laboratory-scale packed bed reactors (PBR) and field-scale constructed filter beds (CFB). Phosphorus extraction and leaching were assessed in batch and leaching experiments using distilled water and ammonium lactate (AL) solution with a 1:20 solid:extractant ratio. The results revealed that both Sa (11.2 mgkg-1) and BC-fortified Sa (20.5 mgkg-1) leached P to percolating water, while P was less likely to leach from GC systems. Extraction with AL showed that the P retained in GC was plant-available and that the GC materials could release 65-90 mgkg-1 of the bound P mass. These findings highlight the need to evaluate the risk of nutrient leaching from filter media used in small-scale wastewater treatment systems with groundwater and surface water as final recipients. For greater sustainability, the P weakly bound in media such as sand and biochar and strongly bound in media such as gas concrete should be recovered by recycling the spent material to agriculture. However, this would require treatment system re-design to make recycling of filter material technically possible.
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| 19. |
- Kholoma, Ezekiel, et al.
(författare)
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Leachability and plant -availability of phosphorus in post-sorption wastewater filters fortified with biochar
- 2019
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Ingår i: Environmental technology. - : Taylor & Francis. - 0959-3330 .- 1479-487X. ; 40:27, s. 3641-3651
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Tidskriftsartikel (refereegranskat)abstract
- Sand and gravel are widely applied for filtering pre- or primary-treated wastewater in small-scale wastewater treatment (SWT) systems. However, ecological materials continue to attract increasing interest in use as retrofits for achieving better performance in removing dissolved contaminants and recovering nutrients from wastewater. In this study, we assessed the plant availability and leachability of phosphorus (P) from sand (Sa) and gas concrete (GC) media previously fortified with biochar (BC) and used for phosphorus (P) removal in laboratory-scale packed bed reactors and field-scale constructed filter beds. Batch and leaching experiments were conducted, with distilled water and ammonium lactate (AL) solutions (1:20 solid–liquid (w/v) ratio) applied as extractants. In the findings, reference (Sa) and fortified (Sa-BC) sand filters leached 11.2 and 20.5 mg P kg−1 respectively, to percolating water while the P seemed less likely to leach from GC systems. Extraction with AL showed that P retained in GC was plant-available and that GC could release up to 90 mg kg−1 of the bound mass. These findings highlight the need to evaluate risks of nutrient leaching from filter media for SWT systems especially where groundwater and surface water are final recipients of such effluents. For greater sustainability of use of the media, the weakly bound P in media such as Sa and BC and strongly bound in media such as GC types of materials may be recovered by recycling the spent material to agriculture. However, this may require re-design of the treatment system especially with respect to particle size to make recycling technically feasible.
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| 20. |
- Kholoma, Ezekiel, et al.
(författare)
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Phosphorus removal from wastewater by field-scale fortified filter beds during a one-year study
- 2016
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Ingår i: Environmental technology. - : Taylor & Francis Group. - 0959-3330 .- 1479-487X. ; 37:23, s. 2953-2963
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Tidskriftsartikel (refereegranskat)abstract
- Due to low availability of alternative technologies, rural communities are unable to comply with national wastewater discharge limits. This study tested the effectiveness of filter bed fortification with biochar on phosphorus removal. Water-tight down-flow beds of sand and gas concrete, constructed alongside a reference sand bed (all 0.8 m deep and 0.75 m2 surface area), were topped with a 0.2 m biochar layer. Pre-treated domestic wastewater with mean concentrations of 6.4 mg/L PO3-4 and 142.6 NTU, was infiltrated at 4 cm/d hydraulic loading rate. Ultimately, the biochar-sand was relatively outstanding in turbidity reduction, achieving < 5 NTU. The biochargas concrete exhibited superior performance in PO3-4 removal, trapping 32.3 g (40.2%), compared with 20.5 g (25.6%) and 15.5 g (19.3%) by biochar-sand and reference bed respectively. However, statistical analysis revealed a weak correlation between pH and biochargas concrete removal efficiency (r2= 0.2). The relationship was stronger for biochar-sand PO3-4 (r2 = 0.5) than reference (r2 = 0.4) bed. Paired samples t-tests showed that incorporating biochar into the sand bed significantly (p =.04) improved its PO3-4 removal efficiency. In conclusion, sand bed fortification with biochar could be an important measure for improving P removal and wastewater clarification efficiency.
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| 21. |
- Nilsson, Charlotte, 1985-, et al.
(författare)
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Effect of organic load on phosphorus and bacteria removal from wastewater using alkaline filter materials
- 2013
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 47:16, s. 6289-6297
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Tidskriftsartikel (refereegranskat)abstract
- The organic matter released from septic tanks can disturb the subsequent step in on-site wastewater treatment such as the innovative filters for phosphorus removal. This study investigated the effect of organic load on phosphorus (P) and bacteria removal by reactive filter materials under real-life treatment conditions. Two long-term column experiments were conducted at very short hydraulic residence times (average similar to 5.5 h), using wastewater with high (mean similar to 120 mg L-1) and low (mean similar to 20 mg L-1) BOD7 values. Two alkaline filter materials, the calcium-silicate material Polonite and blast furnace slag (BFS), were tested for the removal capacity of total P, total organic carbon (TOC) and Enterococci. Both experiments showed that Polonite removed P significantly ( p < 0.01) better than BFS. An increase in P removal efficiency of 29.3% was observed for the Polonite filter at the lower concentration of BOD7 ( p < 0.05). Polonite was also better than BFS with regard to removal of TOC, but there were no significant differences between the two filter materials with regard to removal of Enterococci. The reduction in Enterococci was greater in the experiment using wastewater with high BOD7, an effect attributable to the higher concentration of bacteria in that wastewater. Overall, the results demonstrate the importance of extensive pre-treatment of wastewater to achieve good phosphorus removal in reactive bed filters and prolonged filter life.
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| 22. |
- Renman, Agnieszka, et al.
(författare)
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Long-term phosphate removal by the calcium-silicate material Polonite in wastewater filtration systems
- 2010
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 79:6, s. 659-664
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Tidskriftsartikel (refereegranskat)abstract
- The mineral-based filter material Polonite was tested for its PO4 removal capacity in column and full-scale systems using synthetic and domestic wastewater. Three long-term experiments (67, 68 and 92 wk), operated under different hydrological conditions, were compared. The best PO4 removal capacity (97%) was observed in an intermittent saturated column fed with a synthetic solution (530 L m(-2) d(-1)) without organic matter during 68 wk. An unsaturated column system using municipal wastewater (76.7 L m(-2) d(-1)) showed no tendency for PO4 breakthrough and effluent PO4 concentration was still low (0.2 mg L-1) after 67 wk. For a compact bed filter containing 560 kg of Polonite and fed with 70 m(3) of wastewater from a single house, the average PO4 removal was 89% after 92 wk of operation. The column experiments revealed that a design volume of 1-2 kg of material of a particle size of 2-5 mm was required amount for treating 1 m(3) of wastewater in on-site systems operating at target 90% P mass removal. Poor pre-treatment of the wastewater was suggested to reduce the phosphate removal capacity of Polonite in the bed filter trial, where 8 kg were required per m(3). To measure pH of the treated effluent water proved not to be a simple tool for determining when the filter material is exhausted and should be replaced. (C) 2010 Elsevier Ltd. All rights reserved.
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| 23. |
- Renman, Agnieszka, et al.
(författare)
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Metal removal by bed filter materials used in domestic wastewater treatment
- 2009
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Ingår i: Journal of Hazardous Materials. - : Elsevier BV. - 0304-3894 .- 1873-3336. ; 166:2-3, s. 734-739
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Tidskriftsartikel (refereegranskat)abstract
- Bed filters using reactive materials are an emerging technology for on-site wastewater treatment. Used materials, which are enriched with phosphorus, can be used as a fertiliser or soil amendment. However the materials can also be enriched with metals from the wastewater. Six materials (opoka, sand, Polonite (R), limestone, two types of blast furnace slag) exposed to long-term wastewater loading in columns and in a compact filter well filled with Polonite were investigated for metal removal and accumulation. Wastewater applied to the columns had low heavy metal concentrations in the order Zn > Cu > Mn > Ni > Cr. All columns were able to remove 53%-83% of Zn except those filled with sand. Polonite demonstrated a high removal capacity of Mn (>98%), while only the slag materials were able to remove Ni. All materials showed increased Cu, Cr(III). Mn. Pb and Zn content after filtration. Speciation calculations showed that high concentrations of dissolved organic matter might have prevented efficient metal removal, particularly in the case of Cu. The low content of toxic heavy metals in the studied filter materials studied would probably not restrict their use as a fertiliser or soil amendment.
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| 24. |
- Renman, Agnieszka, 1969-
(författare)
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On-site wastewater treatment : Polonite and other filter materials for removal of metals, nitrogen and phosphorus
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bed filters using reactive materials are an emerging technology for on-site wastewater treatment. Chemical reactions transfer contaminants from the aqueous to the solid phase. Phosphorus is removed from domestic wastewater by sorption to filter materials, which can then be recycled to agriculture as fertilisers and soil amendments. This thesis presents long-term column and field-scale studies of nine filter materials, particularly the novel product Polonite®. Phosphorus, nitro-gen and metals were removed by the mineral-based materials to varying degrees. Polonite and Nordkalk Filtra P demonstrated the largest phosphorus removal capacity, maintaining a PO4-P removal efficiency of >95%. Analysis of filter bed layers in columns with downward wastewater flow, showed that phosphorus, carbon and nitrogen content was vertically distributed, with de-creasing values from surface to base layer. Polonite and Filtra P accumulated 1.9-19 g P kg-1. Nitrogen in wastewater was scarcely removed by the alkaline filter materials, but transformation from NH4-N to NO3-N was >90%. Pot experiments with barley (Hordeum vulgare L.) revealed that after wastewater treatment, slags and Polonite could increase plant production. Batch experi-ments and ATR-FTIR investigations indicated that amorphous tricalcium phosphate (ATCP) was formed in the materials, so some of the accumulated PO4-P was readily available to plants. Low heavy metal contents occurred in the materials, showing that they can be applied as soil amend-ments in agriculture without contamination risks. A full-scale treatment system using Polonite as filter material showed an average PO4-P removal efficiency of 89% for a 92-week period, indicat-ing the robustness of the filter bed technology.
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| 25. |
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| 26. |
- Renman, Agnieszka, et al.
(författare)
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Removal of Phosphorus from Hypolimnetic Lake Water by Reactive Filter Material in a Recirculating System—Laboratory Trial
- 2022
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Ingår i: Water. - Basel, Switzerland : MDPI. - 2073-4441. ; 14:5
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Tidskriftsartikel (refereegranskat)abstract
- A toolbox of methods must be available for the remediation of lakes and water bodies suffering from eutrophication. One method suggested is hypolimnetic withdrawal based on a closed-circuit system. Prior to the start of a pilot-scale test at Lake Hönsan, Sweden, a laboratory trial with containers filled with water and bottom sediment from this lake was performed. A peristaltic pump distributed equal bottom water volume to four columns, two filled with glass beads and two with the filter material Polonite, and then back to the surface of the containers. The reactive filter medium (RFM) removed phosphate (PO4-P) efficiently (98.6%), despite the relatively low influent concentration (390 µg L−1). The control column filled with glass beads, removed 2.9% of the PO4-P. The anoxic sediment, containing 2.47 mg P g−1, released PO4-P, which was indicated by the increased concentration in near-bottom water. The redirected water after RFM filtration had high pH (x¯=11.1); however, an equalization took place in the water mass to a lower but still increased pH value (x¯=8.7) compared to the control (x¯=7.02). This article reports the pros and cons of a full-scale system using the proposed method.
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| 27. |
- Renman, Agnieszka, et al.
(författare)
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Transformation and removal of nitrogen in reactive bed filter materials designed for on-site wastewater treatment
- 2008
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Ingår i: Ecological Engineering. - : Elsevier BV. - 0925-8574 .- 1872-6992. ; 34:3, s. 207-214
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen (N) and phosphorus (P) should be removed and recycled from wastewater in order to reduce the nutrient load to recipient waters, avoid contamination of groundwater and conserve resources. Nitrogen removal and transformation were studied in domestic wastewater percolating in unsaturated conditions through 0.5 m long columns containing potential filter materials. Six materials (three types of slag, limestone, opoka, Polonite(R) and sand) were compared at a design loading rate of 85 L m(-2) d(-1) during 67 weeks. All materials transformed ammonium efficiently to nitrate (>98%). Apparent removal of inorganic N was shown only by the coarsest slag and by Polonite(R), possibly due to losses through volatilisation. All other filter materials leached nitrate at the column effluent. Total N content was highest in the surface layer of the column material, with decreasing values with depth. In contrast, carbon
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| 28. |
- Renman, Agnieszka, et al.
(författare)
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Treatment method to remove dissolved metals from motorway runoff – initial observations and implications for operation and maintenance
- 2021
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Konferensbidrag till NORDIWA, 28 september – 1 oktober, 2021, Göteborg Treatment method to remove dissolved metals from motorway runoff – initial observations and implications for operation and maintenance Magnus Hallberg1, Agnieszka Renman2, Raúl Rodríguez Gómez2, Gunno Renman2, Liselott Berndtsson1 1 Swedish Transport Administration, Stockholm, 2 Royal Institute of Technology, Division of Water and Environmental Engineering, Stockholm A large number of different stormwater treatment systems were designed over the years. Unfortunately, their adaptation to operation and maintenance were not always taken into account. During the extensive construction of treatment plants at the new motorway bypass Stockholm, the Swedish Transport Administration investigate sustainable and maintenance efficient stormwater solutions for removal of dissolved pollutants. Moreover, the environmental authorities claim for high consent limits of stormwater effluent metal concentrations with particular regard to zinc (Zn). For this reason, the Swedish Transport Administration started a project in 2020. Runoff at three sites along a section of the E4 motorway, Stockholm, are used for testing filter materials in large column experiments and full-scale filter wells to assess removal of dissolved pollutants. The impact of particulate matter for filter clogging is also studied. The filter wells, situated at Lilla Essingen, aim to remove dissolved metals from road runoff. The pre-treated water, where the load of particulate matter reduces in an open storage pond, is pumped into two parallel filter wells, each filled with 2.7 m3 Leca Filtralite® P. The filter system received stormwater from July 2020 and the first part of the trial terminated in December 2020. The volume treated during this period was approximately 1300 m3. We performed automatic flow-proportional and occasional grab sampling of influent and effluent stormwater to the filters. The water analyses comprised total and dissolved metals, suspended solids (SS), oil, electrical conductivity, turbidity and pH. We continuously monitored the pressure drop in the filters. The SS and turbidity in the pre-treated, influent water ranged from below 5 up to 170 mg/l and 5.2 to 358 NTU, respectively. The filters removed SS efficiently (78%) and turbidity of effluent water was in average 7.8 NTU. The average removal was for dissolved Zn 94%. The oil index (fraction C10-C40) investigated reached 783 µg/l in the influent but was always below 50 µg/l in the filter effluent. The correlation between turbidity and SS was linear (R2=0.9806). Influent pH was in July and December 7.5 and 7.4 respectively. The filter effluent had a pH of 10.2 in July and 9.5 in December. The filters showed continuous pressure drop during the study period however it did not affect the water flow through the filters. After six months of operation and up to 26 regulated pond volumes, the filter showed no signs of declining purification function or clogging.
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| 29. |
- Renman, Agnieszka, et al.
(författare)
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Water filtration with mineral-based byproducts as a sustainable treatment technology
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the project was to investigate whether the 200 000 ton slag, that is not used optimally or deposited every year, can be alternatively applied as water treatment materials, ensuring future outlets and providing added value for the steel industry and society. Five goals had been set and could be met: test of filter material for purification in small sewage plants, testing of mineral filters for industrial wastewater and stormwater, new technology to build road shoulders on busy roads with slag that simultaneously cleans stormwater, laboratory-tested filter products, and two graduated doctors.Slag's properties can be modified in the furnace to contain minerals that have properties to bind phosphorus or metals from water. Slags can separate both cations and anions from contaminated water, anions even at pH value 10. Furthermore, slag and bark in combined filters are able to remove PFAS and also fluorine by modifying of AOD slag. Some types of slag are recommended to replace sand in soil beds for sewage treatment. Stormwater wells in cities and industry can be equipped with slag filters. Storm water from traffic-intensive roads can be cleaned in the road shoulder with certain types of slag.R&D has been conducted in clear collaboration between industry and academia. The research has been conducted in the laboratory, at the companies and in the field. Implementation has been possible through researchers and companies starting pilot facilities and studying their function and utility to achieve sustainability goals. The analysis made is that different types of Swedish-produced slag are useful by-products, after simple reprocessing or after modifications, in water purification applications. These applications can be of several different types and be interesting for several end users.
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| 30. |
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| 31. |
- Renman, Gunno, et al.
(författare)
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Reaktiva sorbent för fastläggning av fosfor i Östersjöns bottnar
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The release of phosphorus (P) from sediments is of concern for the eutrophication process of the Baltic Sea. In this investigation a number of reactive and alkaline sorbents were tested for their P removal efficiencies in the environment of anaerobic sediments. Batch, pot and column experiments were performed and simulated real bottom conditions. The calcium silicate material Polonite®, a commercial product for P-traps in wastewater treatment, performed best particularly as used for thin-layer placement. The by-product AOD slag also showed promising sorption capacity. The presence of P in the materials after four months use at sediment surfaces was documented by means of ESEM-EDS and the analysis with XANES revealed that for Polonite, amorphous calcium phosphate (ACP) and apatite had formed when saturated with pore water from anaerobic sediments. This study shows promising results for reactive materials to be used as binding agents for the sequestration of P from sediment. Further work will be performed to develop the technology with submerged thin-layer placement for full-scale application.
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| 32. |
- Renman, Gunno, et al.
(författare)
-
Småskaliga lösningar för avloppsrening med mineralbaserade filtermaterial
- 2011
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Mineralbaserade filtermaterial har tidigare visats kunna avskilja fosfor från avloppsvatten, något som kan utnyttjas i hållbara småskaliga avloppssystem. Den verksamma mekanismen är främst utfällning som kalciumfosfater. Fosforn i använda material kan sedan återföras till brukad mark. Dock har de flesta tidigare studier studerat fosforavskiljning i laboratorieskala, med små belastningar och med fosfatsalter istället för avloppsvatten. Syftet med detta projekt var att studera fosforavskiljningsförmågan i fältförhållanden för fyra olika mineralbaserade filtermaterial; Filtra P (Nordkalk Oyj Abp), Polonite (Bioptech AB), hyttsand (SSAB Merox AB) samt wollastonit (Aros Mineral AB). Materialen placerades i kolonner inuti en container, vilken matades kontinuerligt med avloppsvatten vid en relativt hög belastning (1 m/dygn), som är en realistisk nivå då kompakta system används. Försöket lades upp som två delförsök där avloppsvattnets BOD-värde varierades. Resultaten visar att materialen Filtra P och Polonite ur ett rent kemiskt perspektiv klarar av fältförhållandena relativt väl eftersom de avskiljer fosfor effektivt trots ett högt BOD-värde och en hög belastning (> 80 % genomsnittlig avskiljning). Däremot uppvisade Filtra P stora problem med igensättning p.g.a. disintegration och kalcitutfällning, särskilt i försöket med högt BOD-värde, och dessa kolonner fick därför stängas av i förtid. Hyttsand och wollastonit var däremot ineffektiva som fosforavskiljande material under de rådande förhållandena (< 40 % genomsnittlig avskiljning). I samtliga fall visade resultaten att avskiljningen fungerade klart bättre då BOD-värdet är lågt. Projektet visar att det är stor skillnad mellan förhållanden i laboratorieskala och tuffa förhållanden i fält. Såväl BOD-värde som hydraulisk belastning tycks vara viktiga faktorer som påverkar effektivitet och livslängd för filtermaterialen. För att ha en bra fosforavskiljning kan det vara viktigt att ställa krav på en effektiv förbehandling av avloppsvattnet i slamavskiljare och mark/biobädd. Detta bör beaktas i den vidare utvecklingen av material för småskalig avloppsrening.
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| 33. |
- Renman, Gunno, et al.
(författare)
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Sustainable use of crushed autoclaved aerated concrete (CAAC) as a filter medium in wastewater purification
- 2012
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Ingår i: 8th International conference on sustainable management of waste and recycled materials in construction, Gothenburg, Sweden, 30 May – 1 June, 2012. Proceedings. - : ISCOWA and SGI.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Scrap material from the production of autoclaved aerated concrete (AAC) should be considered a valuable by-product and not a waste, as should residues from the demolition of houses built with AAC. This paper presents an innovative use of AAC that can contribute to environmental improvement. We tested crushed AAC (CAAC, 2-4 mm) for its phosphorus (P) removal efficiency by filtering a solution containing phosphate phosphorus (PO4-P) or pure wastewater in batch, bench-scale and field pilot-scale experiments. Slow phosphate removal kinetics of CAAC were demonstrated, but the removal efficiency was very high (93-99%). Mineralogical analyses (by ICP-OES) of the solid CAAC after contact with flowing wastewater yielded concentrations of 39.6 g P kg-1. Application of X-ray powder diffraction (XRPD) for mineral phase identification confirmed that the dominant mineral in AAC was tobermorite (Ca5Si6O16(OH)2 · 4H2O). Dissolution of this crystalline structure was followed by formation of calcium phosphates and the porous, tobermorite-rich material produced proved excellent in removal of P and organic matter from domestic wastewater. Only crushing and sieving to achieve a suitable particle size distribution is needed prior to application in different technical solutions.
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| 34. |
- Rodriguez Gomez, Raul, et al.
(författare)
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Copper and Zinc Removal Efficiency of Two Reactive Filter Media Treating Motorway Runoff-Model for Service Life Estimation
- 2021
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Ingår i: Water. - : MDPI AG. - 2073-4441. ; 13:18
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Tidskriftsartikel (refereegranskat)abstract
- The predominant techniques used for road runoff treatment are sedimentation and filtration. In filtration systems, the ability of the media to adsorb the contaminants is a finite process. Consequently, construction, operation and maintenance managers of such systems should know in advance the service life, i.e., when the used medium should be replaced, and associated costs of operation and maintenance. A batch experiment followed by a packed bed reactor (PBR) experiment addressed the kinetics of the studied media argon oxygen decarburization slag (AOD) and Polonite, followed by the development of a 1D-model to describe the change of concentration of Cu and Zn within time. The batch test results showed that Cu and Zn adsorption followed the Freundlich isotherms for AOD and Polonite. Those results coupled with the linear driving force model and the developed model resulted in good agreement between the PBR results and the simulation. The model was capable to predict (i), the service life at the hydraulic load of 0.18 m/h for AOD (Cu: 395 d; Zn: 479 d) and Polonite (Cu: 445 d; Zn: 910 d), to show (ii) the profile concentration in the PBR within time and the gradient of the concentration along the height of the reactor.
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| 35. |
- Zuo, Minyu, et al.
(författare)
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Phosphorus removal performance and speciation in virgin and modified argon oxygen decarburisation slag designed for wastewater treatment
- 2015
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Ingår i: Water Research. - : Elsevier. - 0043-1354 .- 1879-2448. ; 87, s. 271-281
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Tidskriftsartikel (refereegranskat)abstract
- Argon oxygen decarburisation (ADD) slag may be used for phosphorus (P) removal, as its high pH and weatherable calcium (Ca) minerals provide sufficient Ca2+ and OH- for calcium phosphate (Ca-PO4) precipitation. This study examined the P removal performance of AOD slag for use as wastewater treatment material. Batch experiments were carried out using both synthetic P solution and real wastewater, followed by chemical modelling and X-ray absorption near edge structure (XANES) spectroscopy. The influences of initial P concentration, slag dose and modification by polyethylene glycol (PEG), an effective agent for generation of porous materials, were investigated to determine the optimal conditions for P removal by AOD slag. It was found that virgin AOD slag removed 94.8% of P from a synthetic P solution in 4 h and 97.8% in 10 h. This high P removal was accompanied by a rapid increase in pH from 7.0 to 10.74. The maximum P removal capacity (PRC) from synthetic P solution ranged from 1.3 to 27.5 mg P g(-1). The optimal AOD dose for P removal from wastewater, determined in 8-h batch experiments, was 25 g L-1. PEG modification increased the reaction rate and resulted in higher final pH, increasing PRC by 47.9%. Combined Visual MINTEQ and XANES analysis for detailed examination of P removal mechanisms revealed that the main P removal mechanism was precipitation of calcium phosphate. According to the XANES analysis, the main Ca-PO4 precipitate formed on virgin AOD slag under low initial P concentration and high pH was apatite, while brushite was the dominant product at high initial P concentration and low pH.
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| 36. |
- Hylander, Lars D., et al.
(författare)
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Phosphorus retention in filter materials for wastewater treatment and its subsequent suitability for plant production
- 2006
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 97:7, s. 914-921
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Tidskriftsartikel (refereegranskat)abstract
- Constructed sand filter beds are advantageous for the treatment of wastewater in areas with a low population density. Phosphorus-sorbing materials with additional beneficial characteristics may be used instead of sand. This study aimed at determining and comparing phosphorus (P) retention capacities of amorphous and crystalline blast furnace slags, limestone, opoka, Polonite (R) and sand, for filtering domestic wastewater through columns over a period of 67 weeks. The P-enriched filter materials were subsequently tested for their fertilizer effectiveness in a pot experiment where barley was cultivated. Polonite (R), i.e. calcinated bedrock opoka, was most effective in removing P. This Occurred at a relatively high hydraulic conductivity that reduced the risk of clogging. Barley grown in two types of slag, with a grain size of 0.25-4, mm. was most effective in dry matter production followed by Polonite (R). Fine-grained slags and Polonite (R) were suggested its most suited of the investigated materials to recycle P back to agriculture.
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| 37. |
- Karczmarczyk, Agnieszka, et al.
(författare)
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Phosphorus Accumulation Pattern in a Subsurface Constructed Wetland Treating Residential Wastewater
- 2011
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Ingår i: Water. - Basel : MDPI AG. - 2073-4441. ; 3:1, s. 146-156
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Tidskriftsartikel (refereegranskat)abstract
- A horizontal subsurface flow constructed wetland was investigated after eight years of residential wastewater discharge (150 person equivalents). Twenty core samples distributed over the entire wetland were taken from the soil matrix. The distribution pattern of phosphorus (P) accumulation in the substrate of the wetland was determined using kriging technique and P sorption was related to the content of aluminum (Al), calcium (Ca) and iron (Fe). The correlations found between Al, Ca and Fe content and P accumulation in the bed substrate were weak: R2 = 0.09, R2 = 0.21 and R2 = 0.28, respectively. Great heterogeneity was observed in the distribution of Ca, P and organic matter in the superficial and deeper layers of the bed. Hydraulic problems associated with wastewater discharge and conductivity of the bed substrate were suggested to have negative effects on the wetland performance.
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| 38. |
- Kietlinska, Agnieszka, et al.
(författare)
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An evaluation of reactive filter media for treating landfill leachate
- 2005
-
Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 61:7, s. 933-940
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Tidskriftsartikel (refereegranskat)abstract
- A laboratory bench-scale column study was conducted to evaluate permeable reactive filter materials as a new method for removal of heavy metals and inorganic nitrogen from landfill leachate. Mixtures of sand and peat, blast-furnace slag (BFS) and peat, and Polonite (R) and peat were tested by loading columns with leachate collected from a pond at Tvetaverket Landfill, Sweden. Sand, peat and Polonite (R) represent natural materials. BFS is a by-product from steel-works. The metal treatment efficiencies of the media were assessed and Polonite (R) was found to perform best, where Mn, Fe, Zn and Cu concentrations were removed by 99%, 93%, 86% and 67%, respectively. This material was also able to reduce inorganic N by 18%. The BFS showed good removal efficiency for Cu (66%), Zn (62%), Ni (19%) and Mo (16%). The sand-peat mixture did not demonstrate a promising removal capacity for any of the elements studied with the exception of Cu (25%). The removal of different elements was suggested to be a combination of several factors, i.e. precipitation, ion exchange and adsorption. Prior to full-scale application of reactive filters at a landfill site, matrix selection, filter design and operational procedures must be developed.
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| 39. |
- Kietlinska, Agnieszka, et al.
(författare)
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Nitrogen removal from landfill leachate using a compact constructed wetland and the effect of chemical pretreatment
- 2005
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Ingår i: Journal of Environmental Science and Health. Part A. - 1093-4529 .- 1532-4117. ; 40:07-jun, s. 1493-1506
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Tidskriftsartikel (refereegranskat)abstract
- Onsite treatment of leachate was implemented at the Tveta Landfill, adjacent to the city of Sodertalje, Sweden. The system consists of leachate collection in a pond, precipitation of metals with chemicals, a constructed wetland, and forest irrigation. This article describes the constructed wetland and its effectiveness at removing ammonia in the system. Pulsed-discharge hydrology and wetland ecology formed the basis for the development of a compact constructed wetland (CCW). The system presented here has most design similarities with vertical sub-surface flow wetlands, though this system is run in batch mode. Chemically purified leachate and untreated leachate were applied to separate sections of the CCW using a filling and emptying schedule. A leachate treatment cycle of about 14 days duration was used, involving a 7 day submerged phase followed by a 7 day drained period. The removal efficiency varied between 40 and 75% on a mass basis. A maximum mass removal rate of up to 5.1 g m(-1) d(-1) was achieved in wetlands receiving leachate after chemical pretreatment. In wetlands receiving non-treated leachate a net release of up to 18 g m(-2) N occurred in the form of nitrate. This indicated a considerable nitrification but limited denitrification in those systems. It was unclear whether the chemical treatment enhanced the nitrogen removal efficiency because of lower toxicity and/or content of fewer competing cations, or other mechanisms. Mechanisms responsible for the NH4-N removal in the CCW system have to be further investigated.
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| 40. |
- Renman, Gunno, et al.
(författare)
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A multi-stage treatment system for landfill leachate : design and performance
- 2004
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Ingår i: Waste 2004 - Integrated waste management and pollution control: Policy and practice, research and solutions. - : The Waste Conference Limited, The Barclay centre, University of warwick Science Park, Coventry, UK. ; , s. 528-535
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A new system for on-site treatment of leachate has been implemented at the Tveta landfill, adjacent to the city of Södertalje, Sweden, and an initial investigation of its performance has been carried out. This is a multi-stage treatment system consisting of steps for aeration and sedimentation in an open pond, indoor treatment with chemicals for precipitation of metals, use of a constructed wetland and forest irrigation for removal of nitrogen. Treatment results from 2002 and 2003 show that the system is able to meet very high effluent standards and therefore the water can be discharged to sensitive water bodies. The chemical treatment can be questioned since operational problems occur with clogging of mechanical devices due to precipitation of calcium as well as generally low metal concentrations do not motivate the high treatment costs. The constructed wetland is of novel design with a removal efficiency of up to 75% for NH4-N, corresponding to an inorganic mass removal rate of up to 5.1 g m-2 d-1. Water sampling in a control ditch adjacent to the forest irrigation revealed a concentration of 1 mg/l for NH4-N.
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| 41. |
- Renman, Gunno, et al.
(författare)
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A natural filter substrate for efficient phosphorus removal from wastewater - column studies
- 2003
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Ingår i: Scientific Papers of the Agricultural University of Crakow - Environmental Engineering. - Kraków : Wydawnictwo AR w Krakowie. - 1233-569X. ; :24, s. 397-404
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Tidskriftsartikel (refereegranskat)abstract
- Sorption to the bed substrate is a major phosphorus (P) removal mechanism in constructed wetlands. Hence it is important to select a substrate with high sorption capacity. A column experiment was performed where Polonite®, a product from opoka (a silica-calcite sedimentary rock from Poland) was mixed with Sphagnum peat in a weight proportion of 1:0.8 (column 2, 4) and 1:0.4 (column 3).Secondary treated wastewater with a mean soluble phosphorus (P-PO4) concentration of 5.1 mg·dm-3 was supplied during 378 days by gravity to four columns, 0.3 m in diameter and filled with substrate to 0.5 m. Column1 was filled solely with peat. Two different grain sizes of Polonite®: 0.05-0.2 mm (column 2, 4) and 2-6 mm (column 3) were used in the experiment. The hydraulic residence time varied from 36 to 48 hours during the experiment. The substrate in column 1 and 2 were kept under un-saturated conditions, while saturated conditions prevailed in columns 3 and 4. The column filled with peat showed an overall P-PO4 removal of 18% and an average effluent concentration of 4.2 mg· dm-3. However, after four months of wastewater discharge, the colour of the effluent from column1 exceeded 10000 mg Pt dm-3 and no further analysis of P was carried out. In the other three columns, where Polonite® was present, the average removal was 99%. The mean concentration of P-PO4 in effluent water from these columns was only 0.03 mg dm-3. Conditions of saturated and un-saturated substrates did not reveal any difference in P-sorption capacity. The results obtained show that the incorporation of the reactive media Polonite® into a peat matrix will enhance the long-term P-sorption capacity significantly.
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| 42. |
- Renman, Gunno, et al.
(författare)
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Reactive bed filters for treatment of landfill leachate
- 2004
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Ingår i: Waste 2004 - Integrated waste management and pollution control: Policy and practice, research and solutions. - : The Waste Conference Limited, The Barclay Centre, University of Warwick Science Park, Coventry, UK. ; , s. 491-498
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Konferensbidrag (refereegranskat)abstract
- A laboratory experiment demonstrated the use of reactive bed filters to effectively remove metals and other elements from landfill leachate. Filter media composed of sand/peat, blast furnace slag (BFS)/peat and Polonite®/peat were tested by loading filter columns with leachate collected from a pond at Tveta Landfill, located in Södertalje, Sweden. Leachate was discharged to each column with a hydraulic loading rate of 1.34 m/d. Sand and Polonite® represent natural materials, although the latter is manufactured from the bedrock opoka. BFS is a by-product from steel-works. Polonite® provided the best removal capacity when compared to the other media. Mn, Fe, Zn and Cu were removed by 99%, 93%, 86% and 67% respectively. This filter media was also able to reduce phosphorus by 90% and nitrogen by l8%.The BFS showed good removal efficiency for Cu (66%), Ni (19%) and Mo (16%). Reactive bed filters may be an economical and practical method for augmenting current, and future onsite treatment of landfill leachate disposal systems with metal, phosphorus and nitrogen removal capabilities.
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| 43. |
- Renman, Gunno, et al.
(författare)
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Reactive bed filters for treatment of storm water from roads and motorways
- 2004
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Ingår i: International Scientific-Technical Conference. Surface water, underground water and soils protection along roads and motorways. - : Eurosystem. - 839194994X ; , s. 109-113
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A reactive bed filter is designed according to the purpose of treatment, e.g. for storm water from roads. The construction may be a filter well or a constructed wetland where the most important component is the reactive medium or sorbent. Different types of artificial adsorbents or ion exchange materials are available as commercial products and most of them are utilized when very high treated water standards are required. A filter technology using reactive media has been developed at the Royal Institute of Technology (KTH), where separate filter wells were constructed as a step following the storm water pond. Besides the filter construction, the most important part is the medium or sorbent used. The sorbent is ‘reactive’ for one or several contaminants that have to be removed from the storm water. The term sorbent refers not only to adsorption, but also to processes such as precipitation, ion exchange, complexation and mechanical filtration. Sorption depends heavily on conditions such as pH, concentration of pollutants, ligand concentration, competing ions and particle size. Sorbents may consist of natural materials that are available in large quantities and at a low cost, or of by-products from industrial or agricultural operations. Since they are non-expensive, these materials can be disposed of without expensive regeneration, although one must bear in mind that they can contain hazardous substances after use and have to be treated accordingly. A promising reactive media is Polonite® which has been developed from the bedrock opoka. The paper presents different technical solutions for treating polluted water from traffic areas.
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| 44. |
- Renman, Gunno, et al.
(författare)
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Treatment of phosphorus and bacteria by filter media in onsite wastewater disposal systems
- 2004
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Ingår i: Ecosan - closing the loop. - Eschborn : Deutsche Gesellschaft für Technische Zusammenarbeit. - 3000127917 ; , s. 573-576
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Konferensbidrag (refereegranskat)abstract
- Correctly designed infiltration beds or phosphorus traps are advantageous for the treatment of wastewater in areas with a low population density. The efficiency can be increased by replacing the commonly used sand with materials that have a higher sorption capacity. Some of these materials are capable of delivering the sorbed phosphorus (P) to plants if subsequently used in agriculture, thereby recycling P in crop production in a sustainable way. A long-term column study was performed using municipal wastewater. Columns were filled with seven different filter media. PoloniteÒ, a product from the bedrock opoka, had the largest sorption capacity for P of the studied materials and its high pH resulted in a filtrate of good hygienic quality. No coliform bacteria was found in the effluent from four selected columns and the removal efficiency approached 99.5 %.
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| 45. |
- Renman (Kietlinska), Agnieszka
(författare)
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Treatment of landfill leachate by filtration through reactive filter media (published under the former surname of Kietlinska)
- 2001
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Ingår i: Annals of Warsaw Agricultural University - Land Reclamation. - Warszawa : Warsaw Agricultural University Press. - 0208-5771. ; :31, s. 95-99
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Tidskriftsartikel (refereegranskat)abstract
- A short-term column experiment with sorbents was performed to test their removal efficiency of phosphate-phosphorus (PO4-P) and ammoniacal-nitrogen (NH4-N) from landfill leachate. Twenty litres of leachate was taken from a landfill near Stockholm and contained in average 233 g/L of PO4-P and 139 mg/L of NH4-N. The sorbents used were opoka, calcinated opoka, zeolite, peat and sand. Four columns were used and filled to a volume of 0.15 L with opoka of 0-1 mm grain size (I), sand 2 mm (II), calcinated opoka (0-2 mm) mixed with zeolite (2 mm) in the proportion I: I (III), and peat mixed with calcinated opoka (IV). More than 90% of P was removed in column III and IV. Columns I and II removed only 42 and 39%, respectively. The sorbents were not promising for removal of ammoniacal nitrogen. The highest removal efficiency was found for column III, a removal of 30%.
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