Economic and energetic assessment of different phosphorus recovery options from aerobic sludge

Daneshgar, Saba; Buttafava, A.; Callegari, Arianna; Capodaglio, Andrea G.

doi:10.1016/j.jclepro.2019.03.195

Cited by 51 publications

(23 citation statements)

References 57 publications

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“…The only way to maintain food security without further harming the planet is to move to new paradigms in urban water management [6] with more sustainable technology applications [7] that can lead to a circular economy of nutrients, whereby nutrients are recovered from waste streams and recycled for fertilizer production [8]. Among the various waste streams generated by modern society, urine has attracted particular attention, as it is a concentrated source of N, P, K, and micronutrients, containing 80% of N and 50% of P discharged with human waste, while accounting for less than 1% of the total wastewater flow in urban systems [9].…”

Section: Introductionmentioning

confidence: 99%

Self-Powered Bioelectrochemical Nutrient Recovery for Fertilizer Generation from Human Urine

et al. 2019

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Nutrient recovery from source-separated human urine has been identified by many as a viable avenue towards the circular economy of nutrients. Moreover, untreated (and partially treated) urine is the main anthropogenic route of environmental discharge of nutrients, most concerning for nitrogen, whose release has exceeded the planet’s own self-healing capacity. Urine contains all key macronutrients (N, P, and K) and micronutrients (S, Ca, Mg, and trace metals) needed for plant growth and is, therefore, an excellent fertilizer. However, direct reuse is not recommended in modern society due to the presence of active organic molecules and heavy metals in urine. Many systems have been proposed and tested for nutrient recovery from urine, but none so far has reached technological maturity due to usually high power or chemical requirements or the need for advanced process controls. This work is the proof of concept for the world’s first nutrient recovery system that powers itself and does not require any chemicals or process controls. This is a variation of the previously proposed microbial electrochemical Ugold process, where a novel air cathode catalyst active in urine conditions (pH 9, high ammonia) enables in situ generation of electricity in a microbial fuel cell setup, and the simultaneous harvesting of such electricity for the electrodialytic concentration of ionic nutrients into a product stream, which is free of heavy metals. The system was able to sustain electrical current densities around 3 A m–2 for over two months while simultaneously upconcentrating N and K by a factor of 1.5–1.7.

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Section: Introductionmentioning

confidence: 99%

Self-Powered Bioelectrochemical Nutrient Recovery for Fertilizer Generation from Human Urine

et al. 2019

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“…Under tested conditions, similar P-removal and recovery efficiencies as the previous method were achieved with ACP precipitation. In addition, under either option, costs for P chemical precipitation with ferric or aluminum salts would be avoided, as well as costs for the final disposal of those residues [21]. Liquid-phase P-recovery would also reduce the overall energy demand and related GHG emissions of a treatment facility [22], by cutting requirements for chemical sludge handling, providing replacement P-containing products (extraction of P of from PR requires approximately 2 kWh/kg P [23]) and renewed resources.…”

Section: Discussionmentioning

confidence: 99%

Holistic Approach to Phosphorus Recovery from Urban Wastewater: Enhanced Biological Removal Combined with Precipitation

et al. 2020

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Combined phosphorus (P) removal and recovery from wastewater is a sensible and sustainable choice in view of potential future P-resource scarcity, due to dwindling primary global reserves. P-recovery from wastewater, notwithstanding the relatively small fraction of total global amounts involved (less than 1/5 of total global use ends up in wastewater) could extend the lifespan of available reserves and improve wastewater cycle sustainability. The recovery of the resource, rather than its mere removal as ferric or aluminum salt, will still allow to achieve protection of receiving waters quality, while saving on P-sludge disposal costs. To demonstrate the possibility of such a recovery, a strategy combining enhanced biological phosphorus removal and mineral P-precipitation was studied, by considering possible process modifications of a large treatment facility. Process simulation, a pilot study, and precipitation tests were conducted. The results demonstrated that it would be possible to convert this facility from chemical -precipitation to its biological removal followed by mineral precipitation, with minimal structural intervention. Considerable P-recovery could be obtained, either in form of struvite or, more sustainably, as calcium phosphate, a mineral that also has possible fertilizing applications. The latter would present a cost about one order of magnitude lower than the former.

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“…If successful, conversion from conventional nitrification-denitrification to Anammox process in a WWTP could imply over 60% energy savings for nitrogen control. It should also be considered that recovery of fertilizing elements N and P in usable form would imply indirect energy savings equivalent to those required for their production less those required by the recovery process [66].…”

Section: Towards More Energy-efficient Wwtpsmentioning

confidence: 99%

“…On average, the application of P-recovery technologies could reduce cumulative WWTP energy demand by 17.7%, and it was suggested that up to 27% overall energy advantage could exist between a biological P-recovery facility and a conventional chemical P-removing facility [68]. Implementing P recovery technologies as struvite or other P-containing fertilizer materials could reduce a facility's energy requirements compared to conventional P removal by ferric chloride or ferric sulfate salts [66,69].…”

Section: Towards More Energy-efficient Wwtpsmentioning

confidence: 99%

Energy Issues in Sustainable Urban Wastewater Management: Use, Demand Reduction and Recovery in the Urban Water Cycle

2019

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Urban water systems and, in particular, wastewater treatment facilities are among the major energy consumers at municipal level worldwide. Estimates indicate that on average these facilities alone may require about 1% to 3% of the total electric energy output of a country, representing a significant fraction of municipal energy bills. Specific power consumption of state-of-the-art facilities should range between 20 and 45 kWh per population-equivalent served, per year, even though older plants may have even higher demands. This figure does not include wastewater conveyance (pumping) and residues post-processing. On the other hand, wastewater and its byproducts contain energy in different forms: chemical, thermal and potential. Until very recently, the only form of energy recovery from most facilities consisted of anaerobic post-digestion of process residuals (waste sludge), by which chemical energy methane is obtained as biogas, in amounts generally sufficient to cover about half of plant requirements. Implementation of new technologies may allow more efficient strategies of energy savings and recovery from sewage treatment. Besides wastewater valorization by exploitation of its chemical and thermal energy contents, closure of the wastewater cycle by recovery of the energy content of process residuals could allow significant additional energy recovery and increased greenhouse emissions abatement.

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Economic and energetic assessment of different phosphorus recovery options from aerobic sludge

Cited by 51 publications

References 57 publications

Self-Powered Bioelectrochemical Nutrient Recovery for Fertilizer Generation from Human Urine

Self-Powered Bioelectrochemical Nutrient Recovery for Fertilizer Generation from Human Urine

Holistic Approach to Phosphorus Recovery from Urban Wastewater: Enhanced Biological Removal Combined with Precipitation

Energy Issues in Sustainable Urban Wastewater Management: Use, Demand Reduction and Recovery in the Urban Water Cycle

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