ISO/TC 282/SC 1/WG 1 - Treated wastewater use for irrigation projects

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 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 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 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.