The recovery of phosphorus (P) from sewage sludge, sludge liquor, or ash from monoincineration can be realized with different processes which have been developed, tested or already realized in full-scale in recent years. However, these pathways and processes differ in their amount of P that can be recovered in relation to the total P content in sludge, in the quality of the recovered P product, and in their efforts in energy, chemicals, fuels, and infrastructure required for P recovery. This study analyses selected processes for P recovery from sludge, liquor, or ash in their potential environmental impacts, following the method of Life Cycle Assessment (LCA, ISO 14040/44). Based on available process data from technology providers and end users, these processes are implemented in a hypothetical reference system for sludge digestion, dewatering and disposal in mono-incineration, including potential side-effects on mainstream wastewater treatment with the return load from sludge dewatering. Recovered products (e.g. P or N fertilizer, electricity, district heating) are accounted as credits for substituting equivalent industrial products. Depending on the maturity of the investigated process, collected process data of process efficiency, product quality, and energy and material demand originates from full-scale plants, pilot trials, or prospective modeling (status in 2014). This data is validated with the technology providers, transferred to the reference system and evaluated with a set of environmental indicators for energy demand, global warming, acidification, abiotic resource depletion, eutrophication, and human and ecotoxicity. Results show that pathways and processes for P recovery differ heavily in their amount of recovered P, but also in energy and related environmental impacts (e.g. greenhouse gas emissions). As direct struvite precipitation in sludge or liquor relies on the dissolved amount of P in digested sludge, these processes are only applicable in wastewater treatment plants with biological P removal. Here, they can recover 4-18% of total P in sludge with a relatively low effort in energy and chemicals, reducing return load to the mainstream process and eventually improving sludge dewaterability in case of direct precipitation in sludge. Acidic leaching of P from digested sludge can yield up to 48% of P for recovery, but requires a significant amount of chemicals for control of pH (leaching and precipitation) and for minimizing heavy metal transfer into the product. The quality of products from sludge and liquor is good with low content on heavy metals, leading to a low potential toxicity for humans and ecosystems. Leaching of monoincineration ash with sulphuric acid yields 70% P with moderate chemical demand, but the leached ash and co-precipitated materials have to be disposed, and the product contains some heavy metals. Complete digestion of ash in phosphoric acid and multi-stage cleaning with ion exchangers yields high recovery of 97% P in a high-quality product (H3PO4) and several coproducts, having an overall low environmental impact. Thermo-chemical treatment of ash can recover up to 98% P with moderate energy input in case of integration into an existing monoincineration facility, but the product still contains high amounts of selected heavy metals (Cu, Zn). Metallurgic treatment of dried sludge or ash can also recover up to 81% of P, but the process has still to be tested in continuous pilot trials to validate product quality, energy demand, and energy recovery options. Sensitivity analysis shows that other pathways of sludge disposal (e.g. co-incineration combined with upstream P extraction, direct application in agriculture) may also be reasonable from an environmental point of view depending on local boundary conditions and political targets. In general, the use of life-cycle based tools is strongly recommended to evaluate and select suitable strategies for regional or national concepts of P recovery from sewage sludge.

This paper provides an overview of promising technologies for phosphorus recovery from waste streams in the context of real nutrient recycling and discusses aspects regarding their wide-spread application but also limitations. Not only the technologies themselves, also the recovered materials and their valorization options are addressed. Results of the EU FP7 project P-REX titled “Sustainable sewage sludge management fostering phosphorus recovery and energy efficiency” will be discussed. Since innovation always needs an enabling environment for market penetration, barriers set by the existing legal framework and measures to resolve them will be concluded. To finally achieve a closed loop, the gap between phosphorus recovery and actual recycling has to be bridged. Finally, Goethe’s words are true more than ever: “Knowing is not enough, we must apply! Willing is not enough, we must do!”

This project report summarizes work conducted in work package 12 of the DEMEAU project. Along with Deliverable 12.1 it covers all tasks from work package 12 as formulated in the Description of Work (DoW). This report contains information about (pre-) feasibility studies, design recommendations and pre-treatment options for different types of MAR. The wide range of hydrogeological features encountered in reality makes a site-by-site approach indispensable. As part of this effort the hydrogeological pre-requisites for surface spreading and deep well injection techniques are described in detail. In chapter 2, ten essential hydrogeological parameters are defined by objective criterias. The following chapter outlines and describes how to obtain these essential hydrogeological parameters. This feasibility assessment starts with the screening of the potential site based on a structured procedure. Site investigations start with relatively cheap but numerous field and laboratory testing and continue to more cost-demanding but less numerous tests. With this procedure it is possible to carry out technical site feasibility in a costand time efficient way. The fourth chapter investigates the International Hydrogeological Map of Europe (IHME 1500) as a planning basis for pre-feasibility of new MAR sites. It was found that the IHME 1500 is useful for a pre-assessment, but detailed regional and local scale maps (and investigations) are additionally necessary to effectively assess hydrogeological features. The final chapter deals with pre-treatment options for MAR. Pre-treatment is necessary to remove critical contaminants from the source water to i) enhance system performance and removal efficiencies, ii) ensure the long-term functioning of the system, iii) meet regulatory demands and iv) ensure beneficial uses of the aquifer beyond the attenuation zone. Available pre-treatment methods in relation to source water type and intended end-use are described. Based on chemical concentrations in source water and intended end-use the most appropriate pre-treatment method can be assessed from a table. Altogether this report thus provides guidance in designing new MAR systems based on a sound hydrogeological site characterisation and pre-feasibility assessment based on available information and parameters obtained from structured investigations.

Within Work Area 5 of the DEMEAU project, selected innovative technologies and tools for emerging contaminants removal and monitoring are assessed in their environmental and economic benefits and impacts by using life-cycle based tools such as environmental Life Cycle Assessment (LCA) and economic Life Cycle Costing (LCC). Six case studies were assessed to quantify their environmental and economic profiles and formulate unique selling propositions to promote market uptake and implementation. These case studies include managed aquifer recharge for groundwater replenishment or for drinking water production in combination with advanced oxidation process, hybrid ceramic membrane filtration with powdered activated carbon for tertiary wastewater treatment, automatic neural net control systems to optimize membrane operation, ozonation of wastewater treatment plant effluent, and bioassays as screening tool for water quality monitoring. This report summarizes the study layout, input data, and results of LCA and LCC for all case studies and indicates unique selling propositions based on the outcomes of the assessment.

This project report summarizes work conducted in work package 11. Along with the deliverable 11.1 and milestone report 11 it covers the tasks from work package 11 as formulated in the Description of Work (DoW). The content of the different sections is interrelated, but each section is organized as an independent part. Title of this report differs from DoW because recommendations for optimum design and operation will be handled in the deliverable 12.2. The sections in this report cover various topics and each section can be found as a stand-alone report in the DEMEAU tool box (http://demeaufp7.eu/toolbox/) for download. Detailed summaries can be found for each section separately.

The La Vall d’Uixó (Spain) pilot site has been selected by DEMEAU because it is a new Aquifer Storage Transfer and Recovery (ASTR) site consisting of two injection wells surrounded by farmer wells for irrigation in a water scarce area. Potential water source for this MAR site is the effluent of the local WWTP, which is a quite constant water source in terms of availability, but gives concerns in terms of water quality. The investigations carried out within DEMEAU supports the work previously done by the Water Recovery Project (2011 – 2014), coordinated by IGME (Instituto Geológico y Minero de España) and UJI (Universitat Jaume I). The Water Recovery Project consists of different implementation phases and aimed to establish an appropriate MAR scheme with reclaimed wastewater to counteract salinity ingress in the coastal aquifer. In the third phase of the project two injection wells have recharged 310,000 m3 with water from the Belcaire River. To foster the implementation of the fourth and final phase of the Water Recovery Project, DEMEAU focused on the evaluation of the effluent of the local WWTP as source water for the ASTR system. This has been done by three sampling campaigns to analyse bulk chemistry, emerging pollutants and bioassays in native groundwater (six agricultural wells), Belcaire River (the current source water of the MAR scheme) and WWTP effluent (potential future source water). Risk assessment based on Australian MAR guidelines have been applied to evaluate risks related to the usage of WWTP effluent as source water. The Australian guidelines have been applied in two steps: entry level assessment and maximal risk assessment. Entry level assessment concluded that La Vall d’Uixó is suitable for a MAR scheme using reclaimed water, while maximal risk assessment identified hazards associated to reclaimed water as source water. As La Vall d’Uixó is an agricultural area of citrus crops, the use of reclaimed water for the injection in the MAR system must be compatible with the use of recovered water for irrigation. The risk assessment done in this report considered this end use of water, as there are no drinking water wells in the area. High risks have been identified for inorganic chemicals (conductivity, chloride and bicarbonate) and nutrients (nitrate). Risks associated to inorganics can be minimized by mixing effluent and Belcaire River water 1:1. Bulk chemistry coincided mainly with the description carried out in Water Recovery project, identifying two main quality problems in native groundwater: (1) salinity ingress (2) high nitrate concentration due to the intensive agricultural practices in the area. Ion displacement pattern in groundwater samples clearly indicates on-going salinization and documents minor effects of the injected water on few wells only. Cl/Br ratios indicate additional sources of chloride apart from seawater. It seems plausible that the underlying Keuper formations (Triassic) contribute to salinity ingress and SO4 excess in groundwater to some extent. Chlorides and nitrate are regulated by the implementation in Spain of the EU Water Framework Directive for the Castellón aquifer. The threshold value for nitrate is 200 mg/L, while the threshold value for chloride is 650 mg/L. WWTP effluent has nitrate and chlorides below the threshold concentrations (60 mg/L and 140 mg/L respectively) and, therefore, the MAR with reclaimed water would suppose a reduction of groundwater pollution and a step towards a qualitative good status in the aquifer. In total 63 organic micro pollutants have been analysed in groundwater, surface water and WWTP effluent. WWTP effluent shows elevated concentrations in almost all groups of organic micro pollutants compared to river- or groundwater. Only pesticides are found in higher concentrations in groundwater compared to the effluent. The Belcaire River shows the lowest concentrations for all groups of micro pollutants. It was shown that the Vall d’Uixó aquifer is contaminated by various organic micro pollutants and does not reflect a near natural aquifer condition. The aquifer chemistry in terms of organic micro pollutants reflects the usage of (untreated) effluent for direct irrigation over years. Elevated concentration of artificial sweeteners, analgesics, stimulants, caffeine metabolites and cocaine metabolites were found in WWTP samples taken during weekends compared to workday samples. In contrast, iopromide has been quantified in higher concentrations in the effluent of WWTP in work days than in the weekend, as this contrast media is used in hospitals for diagnostic tests normally carried out from Monday to Friday. These patterns of the effluent of WWTP during the week of weekend could be determinant for the selection of the working days as most suitable days to store treated waste water. In order to link analysed chemical concentrations to the observed toxicity in the samples a procedure based on bioassay-specific relative potency (REP) factors was applied. REP factors are determined by the effect concentrations of the reference compound and of the test compound. Despite the lack of toxicological data for a number of the selected target compounds and the lower relevance of the selected compounds for (eco)toxicological risk assessment, this study greatly demonstrate the usefulness of combined analyses of environmental samples. Effect-based methods could complement conventional chemical analysis in water quality monitoring as pre-screening techniques by (1) identifying toxic “hotspots” for further investigation, (2) assessing the effect of the entire mixture of compounds present in waters and therefore and (3) reduce uncertainty in safety evaluation.