Reclaimed wastewater use alternatives and quality standards

Reclaimed wastewater use is crucial for increasing water availability, improving water resources management, minimising environmental pollution and permitting sustainable nutrient recycling. However, wastewater also contains microbiological and chemical pollutants posing risks to human health and the environment, and these risks have to be handled. Successful use of reclaimed wastewater requires stringent standards for its treatment, disposal and distribution. This report summarises global and country-specific wastewater quality standards for different reclaimed wastewater use schemes, discusses specific standards and describes reclaimed wastewater use applications in two selected countries, Spain and Abu Dhabi Emirate. The World Health Organization (WHO) Guidelines for the Safe Use of Wastewater for Agriculture focus on the protection of public health. The European Commission does not directly regulate wastewater use, but discharge of treated wastewater into water bodies is regulated by Council Directive 91/271/EEC, which requires treated wastewater to have a maximum of 25 mg BOD5/L, 125 mg COD/L and 35-60 mg total solids (TS)/L. In sensitive areas, sewage treatment plant effluent must comply with a maximum of 2 mg total phosphorus/L and 15 mg total nitrogen/L. EU Council Directive 2008/105/EC also sets environmental quality standards for priority substances, i.e. pesticides, polycyclic aromatic hydrocarbons, phenolic compounds and volatile organic compounds. In Spain, the EU directives and Royal Decree 1620/2007 regulate use of reclaimed wastewater. The Royal Decree sets quality criteria for microbial parameters, solids and turbidity for different applications. The Regulation and Standards Bureau (RSB) of Abu Dhabi Emirate sets the quality criteria for water discharging to marine and land environments and used for irrigation. These include limits for organic matter, solids, nutrient, pathogen indicators and helminths. In Spain, agriculture is the largest sector for reclaimed wastewater use, consuming approx. 350 Mm3/year. Landscape irrigation and maintenance of natural hydrological regimes are the second largest users, consuming approx. 50-60 Mm3/year of wastewater each. In contrast, only <0.5% of the water used in industry is reclaimed wastewater. In Abu Dhabi Emirate, reclaimed wastewater is not used in crop cultivation, but most of the wastewater produced is used for irrigation of public parks and roadsides (287 Mm3/year) and in forestry (130 Mm3/year). District cooling in residential areas is another application for wastewater use in Abu Dhabi Emirate. The technologies used to facilitate wastewater treatment vary. The Barcelona metropolitan wastewater treatment plant (Spain), which supplies reclaimed wastewater for use, conducts biological treatment with activated sludge, tertiary treatment with coagulation-flocculation, filtration, UV disinfection, post-disinfection and oxygen saturation. The effluent wastewater complies with the Royal Decree and EU directives. In contrast, five treatment plants in the Navarra region of Spain use secondary treatment with trickling filters or activated sludge, two having lagoons for tertiary treatment. The hygiene quality of effluent from these plants does not comply with the Royal Decree and several fail to remove persistent organic compounds and pharmaceutical residues effectively. In Abu Dhabi Emirate, the largest sewage treatment plant, Mafraq, carries out conventional activated sludge treatment, followed by sand filtration and chlorination. Its effluent complies with RSB standards, but occurrence of pharmaceutical residues in effluent wastewater has been documented in Abu Dhabi. Besides standards and regulations and appropriate treatment, other aspects which need consideration in planning reclaimed wastewater use for various applications include: cultural and socio-economic aspects, willingness of users to accept and pay for treated wastewater, online and real-time water quality monitoring, and reduced energy use and waste generation

EU-Projekt OSCAR: Optimierung von Lebendmulchen, neuen Zwischenfrüchten, Minimalbodenbearbeitung und Wissenstransfer

The EU project OSCAR (“Optimising Subsidiary Crop Applications in Rotations” [http://www.oscar-covercrops.eu]) aims to achieve comprehensive advances in conservation agriculture to improve sustainability of low-input, organic, and conventional farming systems. The research integrates living mulches, dead mulches, or cover crops with the main crops in rotations so as to simultaneously improve crop nutrition, health, and productivity. Coordinated field experiments in addition to three long-term experiments take place in different climatic regions in Europe and Brazil. Economic and ecological impacts including legume root health will be investigated. Private breeders and manufacturers of agricultural equipment are involved in finding adapted solutions by extending the range of potentially useful plant species and by developing appropriate machinery. The potential for useful chemical extraction from the subsidiary crops will also be studied. A central project deliverable is a database supported Decision Support Tool for multilingual stakeholder exchange and dissemination

Functionalized magnetic particles for water treatment

In this study, we have taken the concept of water treatment by functionalized magnetic particles one step forward by integrating the technology into a complete proof of concept, which included the preparation of surface modified beads, their use as highly selective absorbents for heavy metals ions (Zinc, Nickel), and their performance in terms of magnetic separation. The separation characteristics were studied both through experiments and by simulations. The data gathered from these experimental works enabled the elaboration of various scenarios for Life Cycle Analysis (LCA). The LCA showed that the environmental impact of the system is highly dependent on the recovery rate of the magnetic particles. The absolute impact on climate change varied significantly among the scenarios studied and the recovery rates. The results support the hypothesis that chelation specificity, magnetic separation and bead recovery should be optimized to specific targets and applications

Environmental management of water systems under uncertainty

Hydrological drainage/river basins constitute highly heterogeneous systems of coupled natural and anthropogenic water and pollutant flows across political, national and international boundaries. These flows need to be appropriately understood, quantified and communicated to stakeholders, in order to appropriately guide environmental water system management. In this thesis, various uncertainties about water and pollutant flows in drainage/river basins and their implications for effective and efficient water pollution abatement are investigated, in particular for mine-related heavy metal loadings in the Swedish Dalälven River basin and for nitrogen loadings in the Swedish Norrström drainage basin. Economic cost-minimization modeling is used to investigate the implications of pollutant load uncertainties for the cost-efficiency of catchment-scale abatement of water pollution. Results indicate that effective and efficient pollution abatement requires explicit consideration of uncertainties about pollution sources, diffuse contributions of the subsurface water system to downstream pollutant observations in surface waters, and downstream effects of different possible measures to reduce water pollution. In many cases, downstream load abatement measures must be used, in addition to source abatement, in order to reduce not only expected, but also uncertainties around expected pollutant loads. Effective and efficient environmental management of water systems must generally also consider the entire catchments of these systems, rather than focusing only on discrete pollutant sources. The thesis presents some relatively simple, catchment-scale pollutant flow analysis tools that may be used to decrease uncertainties about unmonitored water and pollutant flows and subsurface pollutant accumulation-depletion and diffuse loading to downstream waters

Monitoring, investigation and analysis of pathogens in MBR treated water at Hammarby Sjöstadsverk, Stockholm

This report summarises the findings from operations with AQUA-Q’s online real-time water quality monitoring system on the effluent from a pilot Membrane Bioreactor (MBR,) within the co-financed VINNOVA-project entitled Tomorrows Sewage Treatment Plants – A Utility Production Facility (Morgondagens kommunala vattenrening – en produktionsanläggning för nyttigheter). Significant progress has been made during recent years with regard to real-time water quality monitoring systems for monitoring and control of water quality and water treatment operation. This report provides an evaluation of the efficiency of the MBR process at the R&D-facility Hammarby Sjöstadsverk, Stockholm, Sweden. This includes the monitoring of larger contaminants (>0.2mm) in effluent water of the MBR process. Aqua-Q’s early warning system, WQM-100, has monitored the water quality 24/7 during the spring 2014 and the particle/micro-contaminants removal efficiency of the MBR was evaluated. Aqua-Q’s real-time monitoring system detected that one of the membranes (membrane A) of the MBR-process had a constant leakage of micro-contaminants. Periodic variations in the measured micro-contaminants concentration could have been caused by an overload in MBR process and also by a potential filter breakthrough. However, during the test period no significant problems were observed in the MBR-process control. For evaluation and verification of the indication from Aqua-Q’s real-time monitoring system, complete microbiological analyses were performed with an alternative ISO standard method and by a certified environmental laboratory. The results highlight the importance of real time quality monitoring of processes related to human sources of microbiological growth. Therefore, a better understanding and control of water qualities in water treatment processes is cost and resource effective, and reduces microbiological emissions to the environment.  This report is only available in English

Syrepumpar

How we can use nature to restore marine environments before it is too late. Short version of the WEBAP project’s final report (December 2013

Vattenskador orsakade av baktryck i avloppssystemet - erfarenheter, regler, hantering och tekniska lösningar

De svenska försäkringsbolagens branschorganisation, Svensk Försäkring, har beräknat att de naturskaderelaterade vattenskadorna kostar de svenska försäkringsbolagen minst 300 miljoner kr årligen. De naturskaderelaterade vattenskadorna inkluderar direkta översvämningar och bakvattenskador där avloppsvatten strömmar in i fastigheter via avloppsenheter. Orsaken till dessa skador är vanligen höga vattenstånd, skyfall, eller brister i avloppsnätet på allmän eller privat mark. I Sverige uppskattar försäkringsbolagen att bakvattenskadorna står för ca 80% av de naturskaderelaterade vattenskadorna. De samhällsekonomiska kostnaderna för de naturskaderelaterade vattenskadorna är ännu högre pga. räddningsinsatser, oförsäkrad egendom, mm samt att ca 100 miljoner kr  tillkommer i form av kostnader för självrisker.Pågående klimatförändringar förväntas leda till att de naturskaderelaterade vattenskadorna ökar och för att motverka detta krävs anpassningsåtgärder på alla nivåer i samhället inkluderande; övergripande stadsplanering, hållbar dagvattenhantering, förbättrade avloppsledningssystem, samt åtgärder inom enskilda fastigheter.Denna rapport fokuserar på tekniska lösningar som kan skydda utsatta enskilda fastigheter mot bakvattenskador orsakade av baktryck i det spillvattenförande avloppsledningssystemet. De vanligaste tekniska lösningarna benämns backventiler och uppfordringsanordningar (pumpsystem). Rapporten beskriver erfarenheter, regler och lämplig användning av dessa.Projektets slutsats är att bakvattenskydd kan utgöra en kostnadseffektiv lösning för att skydda stora ekonomiska och ickemateriella värden i utsatta fastigheter. Detta förutsätter att teknikval baseras på risk, skyddsbehov och att installation och underhåll sker på rätt sätt

Läkemedelsrening vid Ullared reningsverk - Utredning om behov och möjligheter för utökad rening av avloppsvatten från mikroföroreningar

Rapporten redovisar resultaten från en förstudie för läkemedelsrening i Ullareds avloppsreningsverk med ozonoxidation. Gekås handelscentrum står för den mest betydande del av belastningen till reningsverket vilket innebär en särskild sammansättning av inkommande avloppsvatten. Dessutom tillhör recipienten (Högvadsån) till ett av regeringens godkända Natura 2000-områden vilket motiverar för att Naturvårdsverket har bidragit med finansiering till projektet

On the Implementation of an MBR Process at Wastewater Treatment Plants

Many large wastewater treatment plants (LWWTPs) face both an increased load due to population growth and urbanisation as well as more stringent effluent quality requirements. In Stockholm, Sweden, for example, commitment to the Baltic Sea Action Plan (BSAP) and the implementation of the European water framework directive combined with an annual growth rate of 1.5% require actions for efficient municipal wastewater treatment, meeting the new requirements. As it is difficult, or even impossible, for existing WWTPs surrounded by residential areas to expand physically, new treatment solutions are needed. Among others, Stockholm Water Company (Stockholm Vatten AB) has therefore decided to upgrade the existing Henriksdal WWTP (850 000 pe), currently operating with a conventional activated sludge (CAS) process, to a membrane bioreactor (MBR). By converting current post-sedimentation basins to membrane separation units and by other related adaptations the facility will be able to increase its capacity by almost the double (1 600 000 pe).Results of pilot scale studies on wastewater treatment by activated sludge combined with MBR

On the Implementation of an MBR Process at Wastewater Treatment Plants

Many large wastewater treatment plants (LWWTPs) face both an increased load due to population growth and urbanisation as well as more stringent effluent quality requirements. In Stockholm, Sweden, for example, commitment to the Baltic Sea Action Plan (BSAP) and the implementation of the European water framework directive combined with an annual growth rate of 1.5% require actions for efficient municipal wastewater treatment, meeting the new requirements. As it is difficult, or even impossible, for existing WWTPs surrounded by residential areas to expand physically, new treatment solutions are needed. Among others, Stockholm Water Company (Stockholm Vatten AB) has therefore decided to upgrade the existing Henriksdal WWTP (850 000 pe), currently operating with a conventional activated sludge (CAS) process, to a membrane bioreactor (MBR). By converting current post-sedimentation basins to membrane separation units and by other related adaptations the facility will be able to increase its capacity by almost the double (1 600 000 pe).Results of pilot scale studies on wastewater treatment by activated sludge combined with MBR