| 1. |
- 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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| 2. |
- 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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| 3. |
- 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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| 4. |
- 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
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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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| 5. |
- 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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| 6. |
- 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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| 7. |
- 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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| 8. |
- 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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| 9. |
- 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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| 10. |
- 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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