Tertiary phosphorus removal to extremely low levels by coagulation-flocculation and cloth-filtration

Abstract

Higher standards in the European Water Framework Directive and national directive demand advanced wastewater treatment for removal of nutrients and organic micropollutants before the discharge into water bodies. Systematic investigations regarding relative dosage and filtration processes for removal of flocculated solids are currently lacking. In this study, the performance of technologies for advanced removal of total phosphorus down to <100 μg/L with pile cloth-filtration (CF) and membrane filtration was verified and synergy effects for the removal of other contaminants were identified. The results show that an over-stoichiometric addition of coagulants of >5 mol Me3+/mol sRP was necessary to achieve soluble reactive phosphorus (sRP) concentrations of <50 μg/L in the effluent. After the coupled process of tertiary phosphorus removal and solids removal, the soluble non-reactive phosphorus (sNRP) concentration regulates the lowest total phosphorus effluent concentration. sNRP is also partially, but not completely, removed by the use of coagulants. CF has proven to be an alternative technology for the removal of phosphorus and total suspended solids below the detection limit.

Semi-crystalline microplastics in wastewater plant effluents and removal efficiencies of post-treatment filtration systems

“…An MF pilot plant was operated to reduce TSS, phosphorous concentrations as well as bacteria and genes. Contrary to our findings, no measureable MPP in the effluent were expected due to findings of Fundneider et al. (2020) , where the MF was reported to be intact and fully functioning.…”

“… A membrane filter (MF) with a 0.1 µm pore size was operated parallel to the PCMF. Details on the pilot plants and their operation are readily available in Fundneider et al. (2020) .…”

“…In the last 20 years tertiary treatment systems have come into focus to tackle increasing problems of phosphorous concentrations ( Fundneider et al., 2020 ), micropollutants ( Fundneider et al., 2021 ) and antibiotic resistant bacteria ( Alexander et al., 2016 ; Fundneider et al., 2019 ). Depending on specific treatment needs, process alternatives include precipitation/flocculation, adsorption or oxidation and disinfection, but rely largely on surface or depth filtration ( Metcalf et al., 1991 ).…”

Pile Cloth Media Filtration for Harvesting Microalgae Used for Wastewater Treatment

“…The approximate 30% contribution of microalgae harvesting to the total production cost [26,27] highlights the economic importance of further innovation in this production step for advancing the technical readiness level of algal biotechnology in wastewater treatment. In contrast, pile cloth media filtration (PCMF) used during tertiary phosphorus removal was able to reach comparable removal rates of 75% to 95% but with a considerably lower energy demand reported as lower than 0.0068 kWh•m −3 [28]. PCMF seems promising as an alternative to other technologies more commonly used for microalgae harvesting, with effluent concentrations of total suspended solids (TSS) lower than 2 mg•L −1 .…”

“…Currently, the application of the PCMF technology revolves around the removal of TSS and the chemical oxygen demand (COD) [30] of phosphorus and microplastics in WWTP effluent [28]. It can also act as a treatment step in micropollutant removal [31], primary filtration, and primary effluent filtration during wastewater treatment [32]; as a treatment step in water reuse systems [33]; as well as in pre-treatment for the removal of algae and TSS in desalination processes [34].…”