| 1. |
- Desa, L., et al.
(author)
-
Improving and upgrading an existing activated sludge with a compact MBBR : disc filters parallel line for municipal wastewater treatment in touristic alpine areas
- 2020
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In: Water practice and technology. - 1751-231X. ; 15:2, s. 515-527
-
Journal article (peer-reviewed)abstract
- Many wastewater treatment plants (WWTP) in touristic areas struggle to achieve the effluent requirements due to seasonal variations in population. In alpine areas, the climate also determines a low wastewater temperature, which implies long sludge retention time (SRT) needed for the growth of nitrifying biomass in conventional activated sludge (CAS). Moreover, combined sewers generate high flow and dilution. The present study shows how the treatment efficiency of an existing CAS plant with tertiary treatment can be upgraded by adding a compact line in parallel, consisting of a Moving Bed Biofilm Reactor (MBBR)-coagulation-flocculation-disc filtration. This allows the treatment of influent variations in the MBBR and a constant flow supply to the activated sludge. The performance of the new 2-step process was comparable to that of the improved existing one. Regardless significant variations in flow (10,000-25,000 m(3)/d) and total suspended solids (TSS) (50-300 mg/L after primary treatment) the effluent quality fulfilled the discharge requirements. Based on yearly average effluent data, TSS were 11 mg/L, chemical oxygen demand (COD) 27 mg/L and total phosphorus (TP) 0.8 mg/L. After the upgrade, ammonium nitrogen (NH4-N) dropped from 4.9 mg/L to 1.3 mg/L and the chemical consumption for phosphorus removal was reduced.
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| 2. |
- Desa, L., et al.
(author)
-
Improving and upgrading an existing activated sludge with a compact MBBR - disc filters parallel line for municipal wastewater treatment in touristic alpine areas.
- 2020
-
In: Water Practice and Technology. - : IWA Publishing. - 1751-231X. ; 15:2, s. 515-527
-
Journal article (peer-reviewed)abstract
- Many wastewater treatment plants (WWTP) in touristic areas struggle to achieve the effluent requirements due to seasonal variations in population. In alpine areas, the climate also determines a low wastewater temperature, which implies long sludge retention time (SRT) needed for the growth of nitrifying biomass in conventional activated sludge (CAS). Moreover, combined sewers generate high flow and dilution. The present study shows how the treatment efficiency of an existing CAS plant with tertiary treatment can be upgraded by adding a compact line in parallel, consisting of a Moving Bed Biofilm Reactor (MBBR)-coagulation-flocculation-disc filtration. This allows the treatment of influent variations in the MBBR and a constant flow supply to the activated sludge. The performance of the new 2-step process was comparable to that of the improved existing one. Regardless significant variations in flow (10,000-25,000 m(3)/d) and total suspended solids (TSS) (50-300 mg/L after primary treatment) the effluent qualityfulfilled the discharge requirements. Based on yearly average effluent data, TSS were 11 mg/L, chemical oxygen demand (COD) 27 mg/L and total phosphorus (TP) 0.8 mg/L. After the upgrade, ammonium nitrogen (NH4-N) dropped from 4.9 mg/L to 1.3 mg/L and the chemical consumption for phosphorus removal was reduced.
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| 3. |
- Kängsepp, P., et al.
(author)
-
First full-scale combined MBBR, coagulation, flocculation, discfilter plant with phosphorus removal in France
- 2020
-
In: Water Practice and Technology. - : IWA Publishing. - 1751-231X. ; 15:1, s. 19-27
-
Journal article (peer-reviewed)abstract
- The suspended solids (SS) concentrations in effluent from moving bed biofilm reactors (MBBRs) used for secondary biological treatment can be up to 500 mg/L. Microscreens (Drumfilters or Discfilters) can be used as alternatives to traditional clarification or dissolved air flotation to remove SS and total phosphorus (TP). This study shows how a small-scale municipal WWTP for 5,700 population equivalent (PE) can be upgraded to 12,000 PE by combining MBBR with coagulation-flocculation tanks and a Discfilter with a total footprint of 160 m2. This long-term investigation demonstrated that even though influent turbidity (range 146-431 NTU) and flow (25-125 m3/h) varied considerably, very low effluent turbidities (below 10 NTU) could be achieved continuously. Furthermore, this compact treatment system can provide average reductions of ammonium (NH4-N) from 19 to 0.04 mg/L, COD from 290 to 10 mg/L, and TP from 4.5 to 0.3 mg/L. The results show that effluent requirements can be reached by combining MBBR, coagulation-flocculation and disc filtration at full scale, without a primary clarifier upstream of MBBR.
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| 4. |
- Kängsepp, P., et al.
(author)
-
Performance and operating experiences of the first scandinavian full-scale discfilter installation for tertiary phosphorus polishing with preceding coagulation and flocculation
- 2016
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In: Water Practice and Technology. - : IWA Publishing. - 1751-231X. ; 11:2, s. 459-468
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Journal article (peer-reviewed)abstract
- Microscreening (using Discfilters) is a widely used technology for suspended solids removal in tertiary effluent streams of wastewater treatment plants. Several pilot studies have shown the feasibility of using coagulation and flocculation in combination with microscreens for advanced phosphorus removal, but the number of fullscale references is still limited. In summer 2014, the first Scandinavian full-scale Discfilter installation with 2-stage chemical pre-treatment (coagulation and flocculation) was started up at the Arvidstorp wastewater treatment plant in Trollhättan (Sweden). The results obtained during the first year of operation proved that low suspended solids and total phosphorus effluent values could be achieved (,5 and,0.2 mg/l, respectively). These results were obtained even during heavy rainfall, when biologically and primary treated water were mixed at the influent of the Discfilter installation, before the coagulation and flocculation tanks. Further analysis of the results showed that Discfilter in combination with coagulant and polymer pre-treatment is a robust and reliable technology with low energy demand (34 Wh/m3) and a high recovery (1.9+0.4% of influent flow discharged as reject).
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