FprEN 16941-2

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Vor-Ort-Anlagen für Nicht-Trinkwasser - Teil 2: Anlagen für die Verwendung von behandeltem GrauwasserRéseaux d'eau non potable sur site - Partie 2: Systèmes pour l'utilisation de l'eau grise traitéeOn-site non-potable water systems - Part 2: Systems for the use of treated greywater93.025Zunanji sistemi za prevajanje vodeExternal water conveyance systemsICS:Ta slovenski standard je istoveten z:prEN 16941-2oSIST prEN 16941-2:2017en,fr,de01-december-2017oSIST prEN 16941-2:2017SLOVENSKI

tã Systems for the use of treated greywater Réseaux d 5eau non potable sur site æ Partie

tã Anlagen für die Verwendung von behandeltem Grauwasser This draft European Standard is submitted to CEN members for enquiryä It has been drawn up by the Technical Committee

If this draft becomes a European Standardá CEN members are bounwhich stipulate the conditions for giving this European Standard the status of a national standard without any alterationä

This draft European Standard was established by CEN in three ofer language made by translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä

CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Serbiaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey and United Kingdomä

Recipients of this draft are invited to submitá with their commentsá notification of any relevant patent rights of which they are aware and to provide supporting documentationä

Warning ã This document is not a European Standardä It is distributed for review and commentsä It is subject to change without notice and shall not be referred to as a European Standardä

EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG

t r s y CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä prEN

prEN 16941-2:2017 (E) 2 Contents Page European foreword ....................................................................................................................................................... 4 Introduction .................................................................................................................................................................... 5 1 Scope .................................................................................................................................................................... 6 2 Normative references .................................................................................................................................... 6 3 Terms and definitions ................................................................................................................................... 7 4 Functional elements and greywater quality.......................................................................................... 8 5 Design .................................................................................................................................................................. 8 5.1 General ................................................................................................................................................................ 8 5.2 Collection ........................................................................................................................................................... 9 5.3 Treatment .......................................................................................................................................................... 9 5.4 Storage ............................................................................................................................................................. 10 5.4.1 General ............................................................................................................................................................. 10 5.4.2 Materials .......................................................................................................................................................... 10 5.4.3 Dimension ....................................................................................................................................................... 10 5.4.4 Capacity............................................................................................................................................................ 10 5.4.5 Structural behaviour ................................................................................................................................... 10 5.4.6 Watertightness .............................................................................................................................................. 11 5.4.7 Connections and internal pipe system ................................................................................................. 11 5.4.8 Access ............................................................................................................................................................... 11 5.4.9 Overflow .......................................................................................................................................................... 11 5.5 Back-up water supply ................................................................................................................................. 11 5.5.1 General ............................................................................................................................................................. 11 5.5.2 Backflow protection device ...................................................................................................................... 12 5.6 Pumping ........................................................................................................................................................... 13 5.6.1 General ............................................................................................................................................................. 13 5.6.2 Pumps for collected greywater ............................................................................................................... 14 5.6.3 Pumps for treated greywater ................................................................................................................... 14 5.6.4 Expansion vessel .......................................................................................................................................... 14 5.6.5 Pump control unit ........................................................................................................................................ 15 5.7 System control with monitoring ............................................................................................................. 15 5.8 Metering .......................................................................................................................................................... 15 5.9 Distribution .................................................................................................................................................... 16 5.10 Risk assessment ............................................................................................................................................ 16 6 Sizing ................................................................................................................................................................. 16 6.1 General ............................................................................................................................................................. 16 6.2 Calculation method ...................................................................................................................................... 16 6.2.1 General ............................................................................................................................................................. 16 6.2.2 Demand and yield hierarchies ................................................................................................................ 17 6.2.3 Basic approach .............................................................................................................................................. 17 6.2.4 Detailed approach ........................................................................................................................................ 18 7 Installation ..................................................................................................................................................... 19 8 Differentiation and identification .......................................................................................................... 20 9 Commissioning .............................................................................................................................................. 21 oSIST prEN 16941-2:2017

prEN 16941-2:2017 (E) 3 10 Quality of non-potable water ................................................................................................................... 21 11 Testing of water quality ............................................................................................................................. 21 12 Maintenance ................................................................................................................................................... 22 Annex A (informative)

Greywater yield and demand ................................................................................... 23 A.1 Greywater yield and demand ................................................................................................................... 23 A.2 Examples of water usage and demand .................................................................................................. 23 Annex B (informative)

Types of greywater systems ..................................................................................... 25 Annex C (informative)

Dye testing ....................................................................................................................... 26 C.1 Dye testing for distribution pipework cross-connections ............................................................. 26 Annex D (informative)

Example for water quality requirements ............................................................ 28 Bibliography ................................................................................................................................................................. 31

prEN 16941-2:2017 (E) 4 European foreword This document (prEN 16941-2:2017) has been prepared by Technical Committee CEN/TC 165 “Wastewater engineering”, the secretariat of which is held by DIN. This document is currently submitted to the CEN Enquiry. The series of standards EN 16941 "On-site non-potable water systems" consists of the following parts: — Part 1: Systems for the use of rainwater — Part 2: Systems for the use of treated greywater oSIST prEN 16941-2:2017

prEN 16941-2:2017 (E) 5 Introduction Ecological and sustainable water management is a goal of greywater management. Greywater varies in volume and composition depending on different sources (see Figure 1) which would need different levels of treatment for use. Therefore greywater systems can vary significantly in their complexity and size. They can be grouped according to the type of system (see Annex B). Greywater can also be used for heat recovery and cooling demands. Principles and design for such applications are not covered by this European Standard.

prEN 16941-2:2017 (E) 6 1 Scope This European Standard specifies the principles of design, sizing, installation, identification, commissioning and maintenance of greywater systems with the purpose of use of greywater on-site. It applies preferably for the use of treated greywater for: — WC flushing; — garden watering; — laundry; — cleaning purposes. This European Standard also specifies the minimum requirements for greywater systems. Excluded from the scope of this European Standard are: — the use as drinking water and for food preparation; — the use for personal hygiene purposes; — direct reuse systems for external use e. g. garden watering; — product design for specific system components; — industrial effluents; — heat recovery and cooling demands. NOTE Conformity with this European Standard does not exempt from compliance with the obligations arising from local or national regulations. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 476, General requirements for components used in drains and sewers EN 806-1, Specifications for installations inside buildings conveying water for human consumption — Part 1: General EN 806-2, Specification for installations inside buildings conveying water for human consumption — Part 2: Design EN 806-3, Specifications for installations inside buildings conveying water for human consumption — Part 3: Pipe sizing — Simplified method EN 806-4, Specifications for installations inside buildings conveying water for human consumption — Part 4: Installation EN 806-5, Specifications for installations inside buildings conveying water for human consumption — Part 5: Operation and maintenance oSIST prEN 16941-2:2017

prEN 16941-2:2017 (E) 7 EN 809, Pumps and pump units for liquids — Common safety requirements EN 1610, Construction and testing of drains and sewers EN 1717, Protection against pollution of potable water in water installations and general requirements of devices to prevent pollution by backflow EN 12050 (all parts), Wastewater lifting plants for buildings and sites EN 12056-4, Gravity drainage systems inside buildings — Part 4: Wastewater lifting plants — Layout and calculation EN 12056-5, Gravity drainage systems inside buildings — Part 5: Installation and testing, instructions for operation, maintenance and use EN 12566-3, Small wastewater treatment systems for up to 50 PT — Part 3: Packaged and/or site assembled domestic wastewater treatment plants EN 13076, Devices to prevent pollution by backflow of potable water — Unrestricted air gap-Family A — Type A EN 13077, Devices to prevent pollution by backflow of potable water — Air gap with non-circular overflow (unrestricted) — Family A — Type B EN 13564-1, Anti-flooding devices for buildings — Part 1: Requirements EN 60335-2-41, Household and similar electrical appliances — Safety — Part 2-41: Particular requirements for pumps (IEC 60335-2-41) EN ISO 4064 (all parts), Water meters for cold potable water and hot water (ISO 4064, all parts) 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 greywater domestic wastewater excluding wastewater from WC and urinal [SOURCE: EN 16323:2014, 2.1.2.1] 3.2 light greywater greywater excluding kitchen wastewater 3.3 storage device unit for the storage of treated greywater 3.4 cistern fixed container for holding water at atmospheric pressure for use as part of the plumbing system oSIST prEN 16941-2:2017

prEN 16941-2:2017 (E) 8 3.5 non-potable water water which has been made available for use, except drinking, food preparation and personal hygiene 3.6 non-return valve device that prevents backflow of water [SOURCE: EN 16323:2014, 2.2.5.12, modified: "wastewater" was changed to "water"] 4 Functional elements and greywater quality Any greywater system is described through four main functional elements: — collection; — treatment; — storage; and — distribution. Greywater systems shall be designed, installed, marked, operated and maintained in such a way that the required level of safety is ensured at any time and that the required servicing work can be easily carried out. Greywater systems shall not cause flooding and therefore shall include potential bypasses and/or properly dimensioned overflows. Volumes and pollution of the different kinds of greywater are depending on their origin. 5 Design 5.1 General The following factors should be identified in order to determine the type and treatment capacity of the greywater system: a) demand and yield, based on: 1) the number and type of intended applications, both present and future; 2) the volume and usage patterns of these applications; 3) discharge figures of greywater connected for use. b) peak capacity treatment rate; c) water quality requirements for the intended use shall be in accordance with local and/or national regulations (an example of water quality requirements is given in Annex D). The different types of greywater systems can be distinguished according to Annex A. NOTE 1 Residual disinfectant or by products might be present in the treated greywater. Colour could also be present. These systems might not be suitable for laundry use or garden watering. Furthermore, if it is intended that treated greywater is to be used for garden watering, water that has been artificially softened might not be suitable for some plants and soils because of salt carryover in the treated greywater. oSIST prEN 16941-2:2017

prEN 16941-2:2017 (E) 9 NOTE 2 It is noted that treated greywater discharge rates vary depending on the appliances that are in use. For example, a shower can discharge at a rate between 0,1 l/s (or less) and 0,3 l/s, while a full bath typically discharges at between 0,4 l/s and 0,5 l/s. The greywater system needs to manage these varying incoming flow rates. The materials selected for the tank and other components should be suitable for the location and temperature ranges anticipated. All components of the greywater system should be capable of withstanding pH levels as low as 5 for the lifetime of the products. Consideration should be given to the environmental impact of materials used. Existing resources on site should be utilized, where appropriate, and materials re-used where possible to limit the environmental impacts of the greywater system. 5.2 Collection Greywater quality and volume depend significantly on the behaviour of the people using the collection appliances. Depending on the type of system, greywater can be collected in different ways. It shall be collected in separate wastewater drainage pipework and allowed to flow from collection appliances to the greywater system by gravity. NOTE Where this is not practicable, e. g. in single-storey dwellings, pumps need to be considered (see 5.6). Collection pipework should be: a) dedicated to greywater; b)

sized and laid out in accordance with EN 12056-2, such that the generation of foam is minimized. As air entrainment is a major factor in the generation of foam, turbulence and the use of bends should be minimized; c) identified (see Clause 8); d) free draining to avoid stagnation. Collection pipework should prevent contaminated water entering the greywater system from other sources. It is recommended that hair traps and filters be used to minimize pollutants entering the greywater system, wherever possible. A bypass should be fitted around the greywater system allowing the collected greywater to flow directly to the foul sewer during periods of maintenance, blockage or system isolation. The bypass should not compromise the drainage system. 5.3 Treatment The intended use of the collected greywater should be considered in order to determine whether treatment is needed and which method is appropriate, e. g. physical, chemical or biological. The collected greywater should only be treated to the extent needed to meet the water quality guidelines of the application being supplied (see Clause 7). After choosing the degree of treatment, the sustainability aspects and the environmental impact should also be considered in order to determine the most appropriate type of treatment. Types of treatment may include one or more of the following sub-steps: a) sedimentation/flotation, e. g. via settlement tanks; oSIST prEN 16941-2:2017

prEN 16941-2:2017 (E) 10 b) screening, e. g. large particulate filtration; c) mechanical fine filtration, e. g. membrane filtration; d) biological treatment, e. g. aeration; e) chemical treatment e. g. precipitation; f) disinfection, e. g. ultraviolet (UV) radiation. 5.4 Storage 5.4.1 General The storage of untreated greywater should be avoided, wherever possible. Where storage of treated greywater is necessary, it may be incorporated as part of the greywater system or provided separately. The selection of storage should take into account: a) the maximum hydraulic capacity treatment rate; b) the necessary storage temperature and allow natural ventilation; c) the maximum storage period and any other conditions stated by the manufacturer of the treatment equipment; d) whether the system is to be dedicated to greywater only or combined with a rainwater harvesting system. 5.4.2 Materials The materials used shall not have a negative effect on the stored water and the environment of the installation. The storage device shall be made from non-translucent material. The materials (e. g. concrete, steel, Polyvinylchloride (PVC-U), Polyethylene (PE), Polypropylene (PP), Glass Reinforced Polyester (GRP-UP)) used for the storage device shall meet the conditions described in EN 12566-3. The materials constituting the submerged components shall be chosen considering the risk of corrosion. 5.4.3 Dimension When prefabricated components are used, the overall dimensions, access and connection dimensions and tolerances shall be stated by the manufacturer. Individual storage devices may be connected to each other. 5.4.4 Capacity The nominal capacity is the maximum volume of water that can be retained within the storage device and shall be stated by the manufacturer or designer within 0,1 m3. The capacity can be determined by testing or calculation. 5.4.5 Structural behaviour Underground storage devices shall withstand the maximum stresses and loads exerted during its handling, installation, use and maintenance. This shall be assessed either by calculation or testing. Above-ground storage devices shall withstand the action of hydrostatic pressure without generating excessive deformation adversely affecting its function. oSIST prEN 16941-2:2017

prEN 16941-2:2017 (E) 11 5.4.6 Watertightness The storage device shall be watertight at the level of: — the walls constituting it; — the couplings ensuring the hydraulic connections, and — the storage device wall penetrations used for the possible passage of electric cables. 5.4.7 Connections and internal pipe system The nominal diameters of the inlet and outlet fittings of the storage device shall be stated by the manufacturer. The inlets, outlets and other connections of the storage device shall be equipped with fittings with standardized dimensions (i. e. sockets, spigots) equipped with seals and enabling assembly using standardized pipes. The overflow pipe is sized to evacuate the entire maximum inflow of the storage device. Protection against the entry of small animals shall be provided. 5.4.8 Access The storage device shall be equipped with an access to permit regular inspection and maintenance. The access shall be secured (e. g. by a cover with a locking feature or sufficient weight). For the access of a person the dimensions given in EN 476 shall be considered. When access of a person is not intended an opening with a dimension (i. e. width for a square section or diameter for a circular section) not less than 400 mm minimum shall be used. Shafts and access covers shall prevent unintentional contamination of the storage device. 5.4.9 Overflow All storage devices shall be equipped with an overflow to allow excess water to be discharged into the sewer system. The overflow shall be equipped with an odour trap. Every overflow shall have provisions to avoid pollution. The mounted parts shall not cause any narrowing of the cross-section. During overflow a siphonage of the storage device shall be avoided. The capacity of the overflow shall be equal or greater than the inlet flow. Protection against sewer backflow as specified in EN 13564-1 shall be provided. 5.5 Back-up water supply 5.5.1 General The greywater treatment system shall incorporate a back-up water supply where a public water supply is available, which may be introduced into: — a break cistern prior to its pump, for delivery to the distribution pipework, e. g. purpose-designed module; or — an intermediate cistern, usually located at high level, e. g. gravity supply; or — the storage device, for treated greywater. oSIST prEN 16941-2:2017

prEN 16941-2:2017 (E) 12 In the case of back-up supply using potable water, the potable supply system shall be protected with an appropriate protection unit (see 5.5.2). The possibility of a flooding of the back-up supply device (e. g. via reflux) has to be eliminated; e. g. by installing the back-up supply device above the backwater level. When the water level in the storage device is below a given minimum, the back-up supply control shall automatically ensure the operational reliability of the system. This can also be achieved by a control system (see 5.7). The back-up supply shall be fitted with a control mechanism which ensures that the amount of water supplied is minimized to that needed for immediate use. It is recommended that this is provided from a make-up module or an intermediate cistern. The design of the system shall ensure that there are no dead legs upstream, e. g. on the potable water supply and suitable turnover of water is achieved, to avoid water to become stagnant. In order to prevent wasting potable water, the storage device with valve-controlled water inputs shall have a warning system so any failure is readily noticeable. 5.5.2 Backflow protection device To prevent non-potable water entering the potable or public water supply, the back-up supply shall be fitted with a protection unit that is capable of providing fluid category 5 (an air gap) in accordance with EN 1717, such as described: — in EN 13076, for family A type A, "AA unrestricted air gap", disconnectors (see Figure 2): An "AA" air gap is a visible unobstructed and complete air gap placed permanently and vertically between the lowest point of the inlet feed orifice and any surface of the receiving vessel that determines the maximum operational level at which the device overflows

Key 1 feed pipe A air gap (double the inner diameter of the feed orifice with a minimum of 20 mm) 2 feed orifice D internal diameter of feed pipe (bore) 3 receiving vessel H maximum water level 4 spillover level

Figure 2 — Unrestricted Type AA air gap according to EN 13076 oSIST prEN 16941-2:2017

prEN 16941-2:2017 (E) 13 — in EN 13077, for family A type B, "AB air gap with non-circular overflow" disconnectors (see Figure 3): An "AB" air gap is a permanent and vertical distance between the lowest point of the feed orifice and the critical water level. The overflow shall be of non-circular design and shall be able to evacuate the maximum flow of water in the event of overpressure

5h) 2 feed orifice 7 critical water level 3 receiving vessel A air gap 4 spillover level D internal diameter of feed pipe (bore) 5 optional warning pipe H maximum water level

h distance between overflow and critical water level Figure 3 — Unrestricted Type AB air gap with non-circular overflow according to EN 13077 Flow rates, head loss and installation requirements shall be taken into account when selecting the backflow prevention device. Where the backflow prevention device is to provide water to the storage device directly and there is a risk of odours venting back into the building, an odour trap shall be installed. 5.6 Pumping 5.6.1 General For systems, other than those which distribute the collected greywater by gravity, one or more pumps shall be used to ensure its continual availability. NOTE 1 The operational safety and hydraulic demand will dictate whether a single pump or multiple-pump systems are needed. The flow rate and the required pressure head of the pump shall be determined in accordance with EN 12056-4 and EN 12050. The pump shall be selected and arranged such that: — energy use and noise are minimized; — air is not introduced into the suction lines; — it is protected against freezing; oSIST prEN 16941-2:2017

prEN 16941-2:2017 (E) 14 — it is provided with isolation valves for maintenance and repair. The pump shall be equipped with dry-run protection, which may be part of the pump or provided by an external control device (see 5.7). Surges, water hammer and hunting from the pump shall be absorbed and prevented from causing undue high pressures, e. g. by the incorporation of expansion v