ISO/TC 282/SC 1 - Treated wastewater reuse for irrigation

This document provides a guideline for the application of various available methods of treated wastewater (TWW) disinfection for an effective inactivation or removal of pathogens from TWW, which is intended for irrigation purposes. This document deals with: — chemical and physical technologies, principles of operation, and establishment of effective doses to be applied, possible interferences, and technical guidance for design and monitoring; — comparison of the advantages and disadvantages of various disinfection methods suitable for TWW; — potential environmental effects of the disinfection methodologies and ways to minimize those impacts; — disinfection at different locations in the TWW use system, including in the wastewater treatment plant, within the distribution system and at the point of use.

This document provides recommendations regarding: — monitoring the quality of treated wastewater (TWW) for irrigation; — monitoring irrigated plants; — monitoring the soil with regard to salinity; — monitoring natural water sources in neighbouring environments; — monitoring the quality of water in storage reservoirs. It puts emphasis on sampling methods and their frequency. Regarding the methods of analysis, this document refers to standard methods or, where not available, to other bibliographical references. NOTE In cases where a monitoring plan already exists, these recommendations can be integrated into this plan. This is notably the case when a broader approach of risk management is implemented, such as the water safety plans (serving as a model for sanitation safety plans) developed by WHO[16].

This document covers the system's components needed for the use of treated wastewater (TWW) for irrigation. Emphasis is placed on irrigation methods, mainly drip irrigation, as this method represents an efficient method of irrigation and water saving, while reducing the pollution of the crops. Despite the fact that water quality and filtration of treated wastewater (herein TWW) using drip irrigation are critical, open irrigation systems are more popular and are frequently used for irrigation with TWW and therefore are covered in this document. This document covers issues related to the main components of a TWW irrigation project, including the following: — pumping stations; — storage reservoirs; — treatment facilities (for irrigation purposes); — filtration and disinfection; — distribution pipeline networks; — water application devices: irrigation system components and treatment. This document is not intended to be used for certification purposes.

This document covers the following issues: — guideline for the design of treated wastewater (TWW) irrigation projects intended to prevent public health risks within the population that has been in direct or indirect contact with the TWW or with any product that has come in contact with the TWW; — specifications of the following: i) TWW quality for irrigation purposes; ii) types of crops for TWW irrigated; iii) TWW and crops qualities integration; iv) use of barriers to reduce risks arising from TWW irrigation; v) correlation between the quality of the TWW, irrigated crops, and the types of barriers that can be used; vi) distance between TWW irrigated areas and residential areas. None of the documents of ISO 16075 are intended to be used for certification purposes.

This document contains guidelines for the development and the execution of projects intending to use treated wastewater (TWW) for irrigation and considers the parameters of climate and soil. The purpose of this document is to provide guidance on all elements of a project using TWW for unrestricted and restricted irrigation, including design, materials, construction, and performance, when used for the following: — irrigation of agricultural crops; — irrigation of public and private gardens and landscape areas, including parks, sport fields, golf courses, cemeteries, etc. These guidelines are intended to provide assistance for the benefit of users of TWW for irrigation. The guidelines relate to the widespread and common ranges of water quality rather than exceptional or unique ones and are intended for the use of professionals, such as irrigation companies (designers and operators), agricultural extension officers or advisors, water companies (designers and operators), local authorities and water utilities. The use of these guidelines by users might require additional specifications. None of the parts of this document are intended to be used for certification purposes. These guidelines suggest the parameters of TWW quality. These parameters include the following: — agronomic parameters: nutrients (nitrogen, phosphorus and potassium), salinity factors (total salt content, chloride, boron, and sodium concentration) and heavy metals' concentration; — pathogen presence. Each of these parameters can have possible impacts on the crops, soil, and public health. The guidelines discuss the possibility of preventing the contaminants' addition during wastewater production and the ability to remove them during the course of treatment. Contaminants of emerging concern (such as pharmaceuticals and personal care product residuals) are outside the scope of this document since up to day, there is no evidence of adverse effects on human health or environment via irrigation with TWW or via the consumption of crops irrigated with TWW. The project should be designed in accordance with the sanitary quality of the TWW in order to avoid disease transmission by the pathogens in the water. The use of these guidelines is encouraged to ensure consistency within any organization engaged in the use of treated wastewater. These guidelines provide the basis for a healthy, hydrological, environmental and agronomic conscious design, operation, monitoring, and maintenance of an irrigation system using treated wastewater.

This document provides guidelines to planners and practitioners on how to adjust irrigation equipment so as to allow direct utilization of treated wastewater (TWW) for irrigation. It deals with the adjustment of all components of irrigation systems to TWW quality in respect to physical, chemical and biological parameters. This document provides guidelines on how to protect irrigation equipment so as to guarantee water systems functionality at high levels of efficiency. This document includes recommendations for a) pumping stations, b) filtration, c) water network systems, d) irrigation equipment: emitters (drippers, sprinklers, mini sprinklers, micro sprinklers, sprayers and irrigation machine (sprinklers and sprayers), e) physical treatment of irrigation equipment, and f) chemical treatment of irrigation equipment. This document defines TWW parameters at the irrigation system inlet after a wastewater treatment plant, in order to allow optimal and continual functioning of the irrigation systems and to allow uniformity of emitters' discharge.

ISO 16075-4:2016 provides recommendations regarding: · monitoring the quality of treated wastewater (TWW) for irrigation; · monitoring irrigated plants; · monitoring the soil with regard to salinity; · monitoring natural water sources in neighbouring environments; · monitoring the quality of water in storage reservoirs. It puts emphasis on sampling methods and their frequency. Regarding the methods of analysis, ISO 16075-4:2016 refers to standard methods or, where not available, to other bibliographical references.

ISO 16075-1:2015 contains guidelines for the development and the execution of projects intending to use treated wastewater (TWW) for irrigation and considers the parameters of climate and soil. The purpose of these guidelines is to provide specifications for all elements of a project using TWW for irrigation, including design, materials, construction, and performance, when used for the following: unrestricted irrigation of agricultural crops; restricted irrigation of agricultural crops; irrigation of public and private gardens and landscape areas, including parks, sport fields, golf courses, cemeteries, etc; irrigation of private individual gardens. These guidelines are intended to provide assistance for the benefit of users of TWW for irrigation. The guidelines relate to the widespread and common ranges of water quality rather than exceptional or unique ones and are intended for the use by professionals, such as irrigation companies (designers and operators), agricultural extension officers or advisors, water companies (designers and operators), and local authorities. The use of these guidelines by farmers might require additional specifications.

ISO 16075-3:2015 covers the system's components needed for the use of TWW for irrigation which relate to various pressure and open irrigation systems specifically drip irrigation as this method represents an efficient method of water delivery and water saving. Despite the fact that water quality and filtration of treated wastewater (herein TWW) using drip irrigation are critical, open irrigation systems are more popular and are frequently used for irrigation with TWW and therefore are covered in this part of ISO 16075. ISO 16075-3:2015 will cover the issues related to the main components of a TWW irrigation project, including the following: pumping station; storage reservoirs; treatment facilities (for irrigation purposes): filtration and disinfection; distribution pipeline network; water application devices: irrigation system components and treatment.

ISO 16075-2:2015 covers the following issues: criteria for the design of treated wastewater (herinafter: TWW) irrigation projects intended to prevent public health risks within the population that has been in direct or indirect contact with the TWW or with any product that has come in contact with the TWW; specifications of the following: the quality of the TWW that can be used for irrigation; the types of crops that can be irrigated with TWW; the combination of the qualities of the irrigated TWW and the types of crops that can be irrigated; the strategy of using barriers that can reduce the risks that arise from TWW irrigation; the correlation between the quality of the TWW, the irrigated crops, and the types of barriers that can be used; the distance required between the TWW irrigation areas and residential areas.