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Westholm, Lena JohanssonORCID iD iconorcid.org/0000-0003-0231-564X
Alternative names
Publications (10 of 45) Show all publications
Envall, I., Fagerlund, F., Westholm, L. J., Bring, A., Land, M., Åberg, C., . . . Gustafsson, J. P. (2023). Existing evidence related to soil retention of phosphorus from on-site wastewater treatment systems in boreal and temperate climate zones: a systematic map. Environmental Evidence, 12(1), Article ID 6.
Open this publication in new window or tab >>Existing evidence related to soil retention of phosphorus from on-site wastewater treatment systems in boreal and temperate climate zones: a systematic map
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2023 (English)In: Environmental Evidence, E-ISSN 2047-2382, Vol. 12, no 1, article id 6Article in journal (Refereed) Published
Abstract [en]

Background: In Sweden there are nearly one million soil-based on-site wastewater treatment systems (OWTSs). OWTSs may contribute to eutrophication of surface waters, due to the discharge of phosphorus (P). Hence, in certain cases, a high P removal rate (up to 90%) of OWTSs is required by Swedish authorities. Since these requirements may have costly consequences to property owners, it is debated whether they are too strict. In this debate, it is often claimed that the soil retention of P occurring in the natural environments may be underestimated by authorities. Soil retention is the inhibition of the transport of P through the ground, due to different chemical, physical and biological processes occurring there. These processes make the P transport slower, which may reduce the unwanted impact on receiving water bodies. However, the efficiency of soil retention of P remains unclear. The objective of this systematic map was to collect, code, organise and elucidate the relevant evidence related to the topic, to be able to guide stakeholders through the evidence base, and to support future research synthesising, commissioning, and funding. The systematic map was carried out in response to needs declared by the Swedish Agency for Marine and Water Management but the conclusions should be valid for a wider range of countries across boreo-temperate regions.

Methods: Searches were made for peer-reviewed and grey literature using bibliographic databases, search engines, specialist websites, and stakeholder contacts. The references were screened for relevance according to a predefined set of eligibility criteria. A detailed database of the relevant studies was compiled. Data and metadata that enable evaluation and discussion of the character and quality of the evidence base were extracted and coded. Special focus was placed on assessing if existing evidence could contribute to policy and practice decision making. Descriptive information about the evidence base was presented in tables and figures. An interactive evidence atlas and a choropleth were created, displaying the locations of all studies.

Review findings: 234 articles out of 10,797 screened records fulfilled the eligibility criteria. These articles contain 256 studies, performed in the field or in the laboratory. Six different study types were identified, based on where the measurements were conducted. Most studies, including laboratory studies, lack replicates. Most field studies are observational case studies.

Conclusions: It is not possible to derive valid generic measures of the efficiency of soil retention of P occurring in the natural soil environment from available research. Neither does the evidence base allow for answering the question of the magnitude of the potential impact of OWTSs on the P concentration in recipients on a general basis, or under what conditions OWTSs generally have such an impact. A compilation of groundwater studies may provide examples of how far the P may reach in x years, but the number of groundwater studies is insufficient to draw any general conclusions, given the complexity and variability of the systems. Future research should strive for replicated study designs, more elaborate reporting, and the establishment of a reporting standard.

Keywords
OWS, OWTS, Septic systems, Septic tanks, Drainfields, Soil treatment, Adsorption, Precipitation, Phosphorus removal, Infiltration, Eutrophication, Sweden
National Category
Environmental Sciences
Identifiers
urn:nbn:se:mdh:diva-62326 (URN)10.1186/s13750-023-00300-7 (DOI)000961586000001 ()2-s2.0-85152562835 (Scopus ID)
Funder
Swedish Research Council FormasSwedish Research Council Formas
Available from: 2023-04-26 Created: 2023-04-26 Last updated: 2023-08-28Bibliographically approved
Westholm, L. J. (2023). Filter media for storm water treatment in sustainable cities: A review. Frontiers in Chemical Engineering, 5, Article ID 1149252.
Open this publication in new window or tab >>Filter media for storm water treatment in sustainable cities: A review
2023 (English)In: Frontiers in Chemical Engineering, ISSN 2673-2718, Vol. 5, article id 1149252Article in journal (Refereed) Published
Abstract [en]

Storm water treatment and management will be more important in the future due to climate changes, e.g., more frequent, and intense rain events that might cause flooding. To meet these challenges, low impact development (LID) technologies such as paved surfaces, green roofs and various bioretention systems have been suggested in urban areas. Various filter media, natural and engineered materials, have been used to amend the LID solutions in field experiments enhancing the removal of different contaminants present in storm water of different kinds. Researchers suggest locally available low-cost media having high capacity to remove pollutants. Other parameters to take into consideration when selecting filter media are clogging, hydraulic parameters. Climatic conditions in different regions, e.g., temperate, or cold climatic zones, do not seem to have a large impact on performance on LID solutions.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2023
Keywords
field trial, heavy metals, low impact development technology, lowcost material, nutrients
National Category
Water Engineering
Identifiers
urn:nbn:se:mdh:diva-62596 (URN)10.3389/fceng.2023.1149252 (DOI)000994858000001 ()2-s2.0-85158090330 (Scopus ID)
Available from: 2023-05-29 Created: 2023-05-29 Last updated: 2023-12-04Bibliographically approved
Sylwan, I., Bergna, D., Runtti, H., Westholm, L. J. & Thorin, E. (2023). Primary and digested sludge-derived char as a Cd sorbent: feasibility of local utilisation. Water Science and Technology, 11, 2917-2930
Open this publication in new window or tab >>Primary and digested sludge-derived char as a Cd sorbent: feasibility of local utilisation
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2023 (English)In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 11, p. 2917-2930Article in journal (Refereed) Published
Abstract [en]

Cadmium (Cd) is a highly toxic metal, occurring in municipal wastewater and stormwater as well as in wastewater from various industries. Char derived from the pyrolysis of municipal sewage sludge has the potential to be a low-cost sorption media for the removal of Cd. However, the balance between possible local char production and demand has not been assessed previously. In this study, the Cd sorption capacities of chars derived from primary (PSC) and secondary sludge (DSC), as well as the feasibility of char production for Cd sorbent purposes, and the pyrolysis energy balance were evaluated. Results showed that the sorption capacity of PSC (9.1 mg/g; 800 degrees C, 70 min) was superior to that of DSC (6.0 mg/g; 800 degrees C, 70 min), and increased with a higher pyrolysis temperature. Pyrolysis of primary sludge had a more favourable energy balance compared with the pyrolysis of digested sludge, however, when accounting for loss of biogas production the energy balance of primary sludge pyrolysis was negative. Assessment of the regional demand (V & auml;ster & aring;s, Sweden) indicated that PSC or DSC may cover the local Cd sorbent demand. However, it was estimated that large char volumes would be required, thus making the use of DSC/PSC less feasible.

Place, publisher, year, edition, pages
IWA PUBLISHING, 2023
Keywords
adsorbent, adsorption, biochar, biosolids, biosorbent, WRRF
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-65130 (URN)10.2166/wst.2023.356 (DOI)001103107800001 ()38096078 (PubMedID)2-s2.0-85179766907 (Scopus ID)
Available from: 2023-12-20 Created: 2023-12-20 Last updated: 2024-01-03Bibliographically approved
Xie, Y., Wang, L., Li, H., Westholm, L. J., Carvalho, L., Thorin, E., . . . Skreiberg, Ø. (2022). A critical review on production, modification and utilization of biochar. Journal of Analytical and Applied Pyrolysis, 161, Article ID 105405.
Open this publication in new window or tab >>A critical review on production, modification and utilization of biochar
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2022 (English)In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 161, article id 105405Article in journal (Refereed) Published
Abstract [en]

There has been an increased interest in the production of sustainable biochar in the past years, as biochar shows versatile physicochemical properties and, can have a wide applicability in diverse fields. Comprehensive studies have been made to characterize biochar produced from various biomass materials, using different production technologies and under different process conditions. However, research is still lacking in correlating biochar properties needed for certain applications with (i) feedstock, (ii) biochar production processes and conditions and (iii) biochar upgrading and modification strategies. To produce biochar with desired properties, there is a great need to establish and clarify such correlations, which can guide the selection of feedstock, tuning and optimization of the production process and more efficient utilization of biochar. On the other hand, further elucidation of these correlations is also important for biochar-stakeholder and end-users for predicting physiochemical properties of biochar from certain feedstock and production conditions, assessing potential effects of biochar utilization and clearly address needs towards biochar critical properties. This review summarizes a wide range of literature on the impact of feedstocks and production processes and reactions conditions on the biochar properties and the most important biochar properties required for the different potential applications. Based on collected data, recommendations are provided for mapping out biochar production for different biochar applications. Knowledge gaps and perspectives for future research have also been identified regarding the characterization and production of biochar. 

Place, publisher, year, edition, pages
Elsevier B.V., 2022
Keywords
Applications, Biochar, Feedstock, Production, Properties
National Category
Energy Engineering
Identifiers
urn:nbn:se:mdh:diva-57195 (URN)10.1016/j.jaap.2021.105405 (DOI)000788825200008 ()2-s2.0-85123241918 (Scopus ID)
Available from: 2022-02-02 Created: 2022-02-02 Last updated: 2022-05-18Bibliographically approved
Sylwan, I., Runtti, H., Westholm, L. J., Romar, H. & Thorin, E. (2020). Heavy metal sorption by sludge-derived biochar with focus on Pb2+ sorption capacity at µg/L concentrations. Processes, 8(12), 1-23, Article ID 1559.
Open this publication in new window or tab >>Heavy metal sorption by sludge-derived biochar with focus on Pb2+ sorption capacity at µg/L concentrations
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2020 (English)In: Processes, ISSN 2227-9717, Vol. 8, no 12, p. 1-23, article id 1559Article in journal (Refereed) Published
Abstract [en]

Municipal wastewater management causes metal exposure to humans and the environment. Targeted metal removal is suggested to reduce metal loads during sludge reuse and release of effluent to receiving waters. Biochar is considered a low-cost sorbent with high sorption capacity for heavy metals. In this study, heavy metal sorption to sludge-derived biochar (SDBC) was investigated through batch experiments and modeling and compared to that of wood-derived biochar (WDBC) and activated carbon (AC). The aim was to investigate the sorption efficiency at metal concentrations comparable to those in municipal wastewater (<1 mg/L), for which experimental data are lacking and isotherm models have not been verified in previous works. Pb2+ removal of up to 83% was demonstrated at concentrations comparable to those in municipal wastewater, at pH 2. SDBC showed superior Pb2+ sorption capacity (maximum ~2 mg/g at pH 2) compared to WDBC and AC (<0 and (3.5 ± 0.4) × 10−3 mg/g, respectively); however, at the lowest concentration investigated (0.005 mg/L), SDBC released Pb2+. The potential risk of release of other heavy metals (i.e., Ni, Cd, Cu, and Zn) needs to be further examined. The sorption capacity of SDBC over a metal concentration span of 0.005–150 mg Pb2+/L could be predicted with the Redlich– Peterson model. It was shown that experimental data at concentrations comparable to those in municipal wastewater are necessary to accurately model and predict the sorption capacity of SDBC at these concentrations. 

Place, publisher, year, edition, pages
MDPI AG, 2020
Keywords
Adsorbent, Biosorbent, Heavy metals, Isotherm models, Municipal wastewater, Sewage treatment
National Category
Environmental Biotechnology
Identifiers
urn:nbn:se:mdh:diva-52782 (URN)10.3390/pr8121559 (DOI)000602391100001 ()2-s2.0-85097001940 (Scopus ID)
Available from: 2020-12-10 Created: 2020-12-10 Last updated: 2023-09-06Bibliographically approved
Envall, I., Fagerlund, F., Johansson Westholm, L., aberg, C., Bring, A., Land, M. & Gustafsson, J. P. (2020). What evidence exists related to soil retention of phosphorus from on-site wastewater treatment systems in boreal and temperate climate zones?: A systematic map protocol. Environmental Evidence, 9(1), Article ID 22.
Open this publication in new window or tab >>What evidence exists related to soil retention of phosphorus from on-site wastewater treatment systems in boreal and temperate climate zones?: A systematic map protocol
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2020 (English)In: Environmental Evidence, E-ISSN 2047-2382, Vol. 9, no 1, article id 22Article in journal (Refereed) Published
Abstract [en]

Background Soil-based on-site wastewater treatment systems (OWSs) are suspected to contribute to eutrophication of surface waters, due to the discharge of phosphorus (P). However, along the flow path between the facilities and surface waters, different processes contribute to delay the transport of phosphorus through the ground. This may reduce the unwanted impact on receiving water bodies. However, the strength and significance of this so-called soil retention remains unclear. In Sweden, there are nearly one million OWSs. To protect surface waters, a high P removal rate (up to 90%) is often required by the local municipalities. However, since these requirements may have costly consequences to property owners, it is debated as to whether they are too strict. In this debate, it is often claimed that the retention of P occurring in natural environments may be underestimated by authorities. Accordingly, there is a need for a scrutiny of the available evidence related to soil retention of phosphorus from OWSs. This is the objective of the planned systematic map. Focus will be on boreal and temperate climate zones. Methods Searches will be made for peer-reviewed articles and grey literature using bibliographic databases, search engines, specialist websites and stakeholder contacts. The references will be screened for relevance according to a predefined set of eligibility criteria. At stage one, after testing and clarifying the eligibility criteria, the references will be single-screened based on title and abstract. At stage two, potentially relevant references will be screened in full-text independently by two reviewers. We will compile a detailed database of the relevant studies. Moreover, a narrative report will be produced, describing the research landscape in general terms. This will be carried out with a conceptual model, describing the processes involved in P retention in natural environments, as a foundation. It will be discussed where the respective studies/study types fit into the conceptual model, and also evaluated how each study/study type can be related to the overarching question of eutrophication. Moreover, we will describe identified knowledge gaps that warrant further primary research effort, as well as identified knowledge clusters that could be suitable for systematic reviews.

Place, publisher, year, edition, pages
BMC, 2020
Keywords
OWS, OWTS, Septic systems, Adsorption, Precipitation, Phosphorus removal, Infiltration, Eutrophication, Sweden
National Category
Environmental Engineering
Identifiers
urn:nbn:se:mdh:diva-51554 (URN)10.1186/s13750-020-00205-9 (DOI)000572992400001 ()2-s2.0-85092536899 (Scopus ID)
Available from: 2020-10-15 Created: 2020-10-15 Last updated: 2023-08-28Bibliographically approved
Sylwan, I., Runtti, H., Thorin, E., Zambrano, J. & Westholm, L. J. (2018). BIOCHAR ADSORPTION FOR SEPARATION OF HEAVY METALSIN MUNICIPAL WASTEWATER TREATMENT. In: : . Paper presented at SMICE2018, Sludge management in a circular economy, Rome, May 23-25, 2018.
Open this publication in new window or tab >>BIOCHAR ADSORPTION FOR SEPARATION OF HEAVY METALSIN MUNICIPAL WASTEWATER TREATMENT
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2018 (English)Conference paper, Poster (with or without abstract) (Other academic)
Keywords
biochar, adsorption, municipal wastewater, sludge, heavy metals, Ni, Pb, adsorption isotherm, Langmuir, Freundlich, Redlich-Peterson
National Category
Water Engineering
Research subject
Energy- and Environmental Engineering
Identifiers
urn:nbn:se:mdh:diva-39348 (URN)
Conference
SMICE2018, Sludge management in a circular economy, Rome, May 23-25, 2018
Projects
SMET - Separation of heavy metals in municipal wastewater treatment
Available from: 2018-05-30 Created: 2018-05-30 Last updated: 2018-05-31Bibliographically approved
Khokhotva, O. P. & Westholm, L. J. (2017). The impact of surface properties of modified pine bark on the mechanism of sorption of heavy metals from aqueous media. Journal of Water Chemistry and Technology, 39(3), 148-154
Open this publication in new window or tab >>The impact of surface properties of modified pine bark on the mechanism of sorption of heavy metals from aqueous media
2017 (English)In: Journal of Water Chemistry and Technology, ISSN 1063-455X, Vol. 39, no 3, p. 148-154Article in journal (Refereed) Published
Abstract [en]

The surface properties of pine bark before and after the treatment with urea solution and the adsorption of Cu(II), Ni(II) and Zn(II) from aqueous solutions at different pH values have been studied. Types of active sorption sites, their surface concentration and change after the bark treatment with urea solution were determined. The results of potentiometric titration were processed by using ProtoFit and FITEQL software programs. The data obtained make it possible to conclude that in the extraction mechanism of heavy metals from water the share of ion exchange decreases and the share of complexation increases. The impact of alkaline and alkaline earth metals in the range of their concentrations up to 3000 mg/dm3 on Cu(II) extraction from model aqueous solutions was also investigated. 

Place, publisher, year, edition, pages
Allerton Press Incorporation, 2017
National Category
Environmental Sciences
Identifiers
urn:nbn:se:mdh:diva-36146 (URN)10.3103/S1063455X17030055 (DOI)000405488600005 ()2-s2.0-85024112076 (Scopus ID)
Available from: 2017-07-27 Created: 2017-07-27 Last updated: 2017-08-10Bibliographically approved
Repo, E., Warchoł, J. K., Johansson Westholm, L. & Sillanpää, M. (2015). Steel slag as a low-cost sorbent for metal removal in the presence of chelating agents. Journal of Industrial and Engineering Chemistry, 27, 115-125
Open this publication in new window or tab >>Steel slag as a low-cost sorbent for metal removal in the presence of chelating agents
2015 (English)In: Journal of Industrial and Engineering Chemistry, ISSN 1226-086X, E-ISSN 1876-794X, Vol. 27, p. 115-125Article in journal (Refereed) Published
Abstract [en]

Industrial byproduct, steel slag was used as a low-cost sorbent for the removal of Co(II), Ni(II), Cd(II), and Pb(II) from aqueous solutions containing chelating agents; EDTA, citrate, and oxalate. Equilibrium and kinetic studies were conducted. Clear dependency between speciation of metals and their sorption behavior was observed. Precipitation and adsorption were suggested as main mechanisms. Diffusion played an important role in the kinetics of metal removal. Notable leaching of elements was observed when steel slag was in contact with the solutions under study. Modification with chitosan was successfully used to prevent leaching and improve the sorption capacity of steel slag.

Keywords
Adsorption, Byproduct slag, EDTA, Low-cost sorbent, Metal chelates, Water treatment, Chelation, Costs, Leaching, Lead, Metals, Slags, Sorption, Chelating agent, Industrial by-products, Kinetic study, Low cost sorbents, Metal chelate, Sorption behaviors, Sorption capacities, Chemicals removal (water treatment)
National Category
Environmental Engineering
Identifiers
urn:nbn:se:mdh:diva-27678 (URN)10.1016/j.jiec.2014.12.025 (DOI)000357225200016 ()2-s2.0-84930817863 (Scopus ID)
Available from: 2015-03-06 Created: 2015-03-06 Last updated: 2017-12-04Bibliographically approved
Hokkanen, S., Repo, E., Johansson Westholm, L., Lou, S., Sainio, T. & Sillanpää, M. (2014). Adsorption of Ni2+, Cd2+, PO4 3- and NO3 - from aqueous solutions by nanostructured microfibrillated cellulose modified with carbonated hydroxyapatite. Chemical Engineering Journal, 252, 64-74
Open this publication in new window or tab >>Adsorption of Ni2+, Cd2+, PO4 3- and NO3 - from aqueous solutions by nanostructured microfibrillated cellulose modified with carbonated hydroxyapatite
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2014 (English)In: Chemical Engineering Journal, ISSN 1385-8947, Vol. 252, p. 64-74Article in journal (Refereed) Published
Abstract [en]

The adsorption of Ni2+, Cd2+, PO4 3- and NO3 - by carbonated hydroxyapatite (CHA) modified microfibrillated cellulose (MFC) was studied in the aqueous solution. The modified adsorbent was characterized using elemental analysis, FTIR, SEM and EDAX analysis. The adsorption studies were conducted in batch mode. The effects of pH, contact time, the concentration of metals and the regeneration efficiency were studied. The removal of Ni2+, Cd2+, PO4 3- and NO3 - was not pH dependent. The maximum removal capacities of the CHA/MFC adsorbent for Ni2+, Cd2+, PO4 3- and NO3 - were 2.021, 1.224, 0.843 and 0.209mmol/g, respectively. The Langmuir and Sips models were representative to simulate adsorption isotherms. The results of adsorption kinetic indicate that adsorption was very fast for all studied compounds.

Keywords
Adsorption, Carbonated hydroxyapatite (CHA), Isotherms, Nanocellulose, Water treatment
National Category
Engineering and Technology Natural Sciences
Identifiers
urn:nbn:se:mdh:diva-25228 (URN)10.1016/j.cej.2014.04.101 (DOI)000339601000009 ()2-s2.0-84901198503 (Scopus ID)
Available from: 2014-06-13 Created: 2014-06-13 Last updated: 2016-05-13Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-0231-564X

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