| 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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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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| 10. |
- 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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