| 1. |
- Ciuk Karlsson, Susanna, et al.
(författare)
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Hydraulic Properties and Reduction of COD, Phosphorus and Nitrogen in a Sand Filter used for Greywater Treatment – Simulation and Verification
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A vertical flow sand filter is a simple, effective and inexpensive system for treating greywater. The performance of sand filters treating artificial greywater was tested in the laboratory over a time period of 113 days. The filters consisted of columns (0.2 m diameter) filled with sand to a height of 0.6 m. The hydraulic properties of the filters were measured as well as the inflow and outflow concentrations of COD, BOD5, total and phosphate phosphorus and total-, ammonia- and nitrate nitrogen. To get a better quantitative understanding of the treatment processes inside the filters, the HYDRUS-CW2D computer software was used to simulate the filters. The simulation of water flow through the filter could be well fitted to the measured flow by adjusting three model parameters: the air entry value, the pore size distribution index, and the pore connectivity parameter. For the COD reduction the simulated results agreed well with experimental data after an adjustment of the microbial lysis parameters of HYDRUS-CW2D. The simulated reduction of COD was 65 %, while a 72 % reduction was measured for the filters in the lab. Simulated reduction of phosphorus in the sand filter effluent corresponded well to the measured reduction: the simulated reduction of phosphorus was 72 % while the experimental filters achieved a 79 % reduction. Also, the simulated effluent concentrations of nitrate compared quite well to the measured values. Almost no reduction (4 %) in total nitrogen took place in the experimental filters, which agreed with the simulated reduction (0 %). For the phosphorus and nitrate components in HYDRUS-CW2D, so far no changes have been made to the default parameters.
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| 2. |
- Ciuk Karlsson, Susanna
(författare)
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Simulating water and pollutant transport in bark, charcoal and sand filters for greywater treatment
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A septic tank combined with a sand filter is the most common onsite wastewater treatment system worldwide, since it is a simple, lowcost and reliable treatment method. Alternatives to sand in filters could be advantageous in terms of availability of material and enhanced treatment properties. In this study, flow dynamics and pollutant transport in three filter materials; sand, pine bark and activated charcoal, intermittently dosed with artificial greywater, were simulated using the HYDRUS wetland module. The simulated results were compared with observations from laboratory filters and model hydraulic and microbial parameters were calibrated. Emphasis was placed on simulating the removal of organic pollutants by each filter type. Furthermore, for the bark and charcoal filters, removal of organic matter was simulated for different hydraulic and organic loading rates (HLR = 32 and 64 l m⁻² day⁻¹ and OLR = 13-6 and 28 g BOD₅ m⁻² day⁻¹). Comparing simulated with measured cumulated effluent volume, the normalised root mean square error for all three filter materials was small (0.7-3.5%). The simulated bark filter COD removal in different loading regimes (HLR = 32 and 64 l m⁻² day⁻¹, OLR = 13-16 and 28 g BOD₅ m⁻² day⁻¹) was overestimated by 13-20 percentage points compared with the measured values. When release of organic matter from the bark material itself was accounted for, the difference was reduced to 2-10 percentage points. Simulation of the charcoal filter demonstrated 94 and 91 % removal of COD for HLR = 32 and OLR = 13 - 16 g BOD₅ m⁻² day⁻¹, which compared well with the measured values, 95 ± 2 % and 89 ± 11 %, respectively. However, simulated COD removal for Run 2 (70%) and Run 5 (72%) was low compared with the measured values (90 ± 7 and 84 ± 4 %). The measured sand filter effluent concentration of COD was 245 mg l⁻¹ and the simulated effluent concentration of COD was 134 mg l⁻¹ for HLR = 32 and OLR = 14 g BOD₅ m⁻² day⁻¹. After including an effect of water flow along the column wall in the model, the simulated effluent concentration of COD was 337 mg l⁻¹. These simulations of bark, charcoal and sand filters improved understanding of filter functions and identified possible filter design developments.
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| 3. |
- Ciuk Karlsson, Susanna, et al.
(författare)
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Simulation and verification of hydraulic properties and organic matter degradation in sand filters for greywater treatment
- 2015
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 71, s. 426-433
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Tidskriftsartikel (refereegranskat)abstract
- To evaluate the treatment performance of vertical flow sand filters, the HYDRUS wetland module was used to simulate treatment in an experimental set-up. The laboratory filters were intermittently dosed with artificial greywater at a hydraulic loading rate of 0.032 m(3) m(-2) day(-1) and an organic loading rate of 0.014 kg BOD5 m(-2) day(-1). The hydraulic properties of the filter were characterised, as were inflow and outflow concentrations of chemical oxygen demand (COD), biochemical oxygen demand (BOD), ammonia, nitrate and total nitrogen. The inverse simulation function of the HYDRUS software was used to calibrate the water flow model. The observed effect of water flowing faster along the column wall was included in the inverse simulations. The biokinetic model was calibrated by fitting heterotrophic biomass growth to measurements of potential respiration rate. Emphasis was put on simulating outflow concentrations of organic pollutants. The simulations were conducted using three models of varying degree of calibration effort and output accuracy. The effluent concentration was 245 mg COD L-1 for the laboratory filters, 134 mg COD mg L-1 for the model excluding wall flow effects and 338 mg COD mg L-1 for the model including wall flow effects.
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