Evaluating new processes and concepts for energy and resource recovery from municipal wastewater with life cycle assessment

Abstract

Energy and resource recovery from municipal wastewater is a pre-requisite for an efficient and sustainable water management in cities of the future. However, a sound evaluation of available processes and pathways is required to identify opportunities and short-comings of the different options and reveal synergies and potentials for optimization. For evaluating environmental impacts in a holistic view, the tool of life cycle assessment (LCA, ISO 14040/44) is suitable to characterize and quantify the direct and indirect effects of new processes and concepts. This paper gives an overview of four new processes and concepts for upgrading existing wastewater treatment plants towards energy positive and resource efficient wastewater treatment, based upon an evaluation of their environmental impacts with LCA using data from pilot and full-scale assessments of the considered processes.

Towards the Implementation of Circular Economy in the Wastewater Sector: Challenges and Opportunities

“…Again, the simultaneous recovery of nitrogen and phosphorus as struvite by means of crystallization/precipitation is the main alternative [111]. Thus, it can be precipitated in the sewage sludge through acidic leaching followed by the chemical precipitation of phosphorus [143]. However, heavy metals can be present in the sludge, thus, requiring a pre-treatment to avoid its presence in the fertilizer.…”

“…High operating costs. [11,115,143] Oxidative processes, including Aqua Reci and LOPROX/PHOXNAM, can also be employed to recover phosphorus. In the first one, supercritical water oxidation followed by acid/alkaline leaching and precipitation were used, thus, recovering phosphorus as calcium phosphate, iron phosphide, and aluminium phosphide from thickened, dewatered, or digested sludge.…”

Energy use and carbon footprints differ dramatically for diverse wastewater-derived carbonaceous substrates: An integrated exploration of biokinetics and life-cycle assessment

“…However, further research is still needed to determine how the offsets of embodied energy for varying energy recovery strategies change in relation to both scale and technologies. This is important because the scale of implementation has been observed to affect the energy consumed or recovered in wastewater treatment with integrated resource recovery 22, 23 . The residual biosolids released from the anaerobic digestion (AD) systems still have sufficient energy potential for further capture, ranging from 0.099 to 0.153 kWh/m 3 (Fig.…”

Assessment of a Field Tidal Flow Constructed Wetland in Treatment of Swine Wastewater: Life Cycle Approach

“…The initial function of the tidal flow CW was to remove pollutants from the influent swine wastewater by the production of purified effluent. Thus, the Functional Unit (FU) of the present assessment is defined in quantitative terms as the production of 1 m 3 of purified wastewater [11]. As the swine wastewater collecting system in the farm had already existed, it was not included in the present LCA.…”