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Technical Practice Updates (TPUs) 

Technical Practice Updates (TPUs) are a unique kind of resource provided by WEF for its members and other practicing professionals who need timely and accurate information on emerging technical topics.  Developed under the auspices of WEF’s Technical Practice Committee by diverse and balanced task forces using WEF’s established consensus procedures, these documents provide sound and timely information on emerging scientific, engineering, and other practice-related issues.  They are provided at no charge to WEF members and are available for purchase by nonmembers.  (Note: WEF members, you will be prompted to enter your WEF Membership ID number and password).   

  • Overview of Selenium Issues in Industrial Wastewater Discharges (July 2010) (Members) (Nonmembers)
    This TPU provides an overview of the major technical and regulatory issues surrounding compliance with low-level limits for selenium in industrial discharges. Selenium is listed as a “priority” toxic pollutant under the federal CWA, and most states have incorporated selenium criteria into their water quality standards regulations. This document focuses on issues of concern to affected industrial sectors in the United States by summarizing the current state of practice for selenium treatment, identifying significant gaps in the knowledge base, and outlining the work needed to address these unknowns.


  • Understanding and Applying New Sustainability Metrics in the Water Sector (March 2010) (Members) (Nonmembers)
    This TPU is focused on providing guidance on sustainability metrics and terminology as a basis for clear communication. The water sector has been applying sustainability principles for many years, by considering social, economic, and environmental effects when evaluating water sources; by designing wastewater treatment facilities to reduce environmental effects on the receiving waters; and providing reuse of water to reduce economic, environmental, and social burdens caused by over-extraction of water. This TPU will help water professionals to understand the terminology of sustainability and the main metrics used to assess and measure sustainability.
  • Protocols for Estimating Greenhouse Gas Emissions from Municipal Wastewater Sources (October 2009) (Members) (Nonmembers)
    This TPU provides municipal utility managers and other interested professionals with a brief, consensus-based summary of existing standardized protocols for greenhouse gas (GHG) emissions estimation in advance of regulation. The intent of this TPU is to initialize WEF’s participation in the development of an industry standard methodology for facility-level estimation of GHG emissions for WWTPs congruent with accepted standards. The methodology seeks to inform and satisfy regulatory and voluntary reporting requirements and facility planning efforts in a way that is transparent and defensible. In addition, this TPU supports GHG emissions estimates that can be used as sustainability metric in a “triple bottom line” (economic, social, and environmental) approach to project evaluation and prioritization.

  • Environmental Management Systems: Advancing Sustainability (October 2009) (Members) (Nonmembers) 
    This TPU addresses how an environmental management system (EMS) might be used to manage issues related to sustainability. The Brundtland Commission defined sustainable development as development that “meets the needs of the present without compromising the ability of future generations to meet their own needs.” Using a sustainability model with an EMS can help ensure that environmental initiatives are implemented and maintained. Many utilities have implemented an EMS to assist managers in dealing with challenges and making decisions. These utilities can document tangible, measurable benefits, including resource management, economic and financial benefits and incentives, and environmental and operational efficiency and effectiveness.

  • Evolving Methodology for Rating Watershed Sustainability in Preparation for Possible Certification (September 2009) (Members) (Nonmembers)
    This TPU proposes a watershed rating methodology that combines and expands existing elements used to assess the sustainability of a watershed, including human use of physical characteristics, water and wastewater treatment facilities, and significant industrial facilities. Inherent in these discussions is the concept that human activity, at a minimum, should only use nature’s resources at a rate at which they can be safely replenished naturally so that future generations can meet their own needs. It has now been proposed that it may be possible to apply certification to an entire watershed. This TPU tries to show how steps might be taken in this direction and to address how a foundation might be established that could provide the basis for a subsequent certification process. 


  • Direct Addition of High-Strength Organic Waste to Municipal Wastewater Anaerobic Digesters (May 2010) (Members) (Nonmembers) 
    The main purpose of this TPU is to provide a high-level overview of some of the potential benefits and challenges of direct co-digestion of high-strength organic wastes with municipal wastewater sludge. The intent of this publication is not to provide a comprehensive technical document on co-digestion. Rather, and the intent is to provide enough cursory information to encourage further exploration into existing and future WEF publications and activities focused on anaerobic co-digestion. Engineers, operators, utility managers, and regulators should regard this TPU as an introduction to the topic to help understand the potential for co-digestion at their own facilities. 

  • Sudden Increase and Regrowth of Fecal Coliforms in Anaerobically Digested Biosolids (July 2008) (Members) (Nonmembers)
    This TPU presents a summary of the current body of knowledge and a preview of ongoing research on the issue that some wastewater treatment plants using anaerobic digestion and certain dewatering processes have experienced increases in fecal coliform concentrations immediately after dewatering and/or conveyance. This document is an update of the August 2006 Technical Practice Update (TPU) and includes more recent information since the original TPU was published. 

Collection Systems 

  • Wastewater System Capacity Sizing Using a Risk Management Approach (May 2007) (Members) (Nonmembers)
    This TPU introduces municipal wastewater system owners and operators to a risk-based approach for determining the capacity of their collection and treatment systems and compares the risk management approach to capacity and sizing decisions with traditional approaches. The risk-based approach is taken in part from WEF’s Guide to Managing Peak Wet Weather Flows in Municipal Wastewater Systems (Guide) (WEF, 2006). This TPU is not meant to provide detailed protocols for a risk-based approach, rather, how the decision framework can be applied to wet weather alternatives analysis and level of service determinations. 


  • Analytical Methods and Monitoring Technologies for Microconstituents (May 2007) (Members) (Nonmembers)
    This TPU discusses the types and development direction of analytical methods and technologies used to identify and quantify these materials and impart a general understanding of how to interpret the quality of reported information.

  • Current Regulatory Framework for Microconstituents in Water (November 2007) (Members) (Nonmembers)
    This TPU provides an analysis of the current state of knowledge on federal regulatory mechanisms in the United States for microconstituents in the environment. Regulatory strengths and weaknesses and examples of potential solutions are examined.

  • Effects of Wastewater Treatment on Microconstituents (May 2007) (Members) (Nonmembers)
    This TPU specifically examines the effect of wastewater treatment on some of the known or suspected microconstituents and the potential treatment technologies for their removal at wastewater treatment plants based on a survey of the literature. This is not to suggest that we should look solely to WWTPs to protect the quality of the water environment. Rather, a holistic approach involving source reduction and a variety of other strategies should be considered.

  • Microconstituents in Biosolids (July 2007) (Members) (Nonmembers)
    Recent studies documented in this TPU indicate the presence of pharmaceuticals, polyaromatic hydrocarbons, sterols, and other microconstituents in Class B biosolids, regardless of the biosolids treatment technologies used. This TPU serves as a resource for sound and accurate information on the current state of knowledge of these microconstituents until future standard practices are fully developed. Users can draw upon this information to better understand the issue and how it may impact them, and to assist in making informed decisions as to how they might proceed to manage their own biosolids programs in such a manner as to protect the health and welfare of their employees, the public, and the environment.

  • Nanoparticles (May 2008) (Members) (Nonmembers)
    This TPU provides one of the first overviews of the potential effects of manufactured nanomaterials in wastewater treatment plants. Nanotechnology refers to the emerging field that creates and uses nanoscale material (manufactured nanomaterial) where the particle size is in the range of 1 to 100 nanometers (nm) in at least one dimension. Nanotechnology facilitates manipulation of materials at the molecular level. Because of their extremely small size and their ability to be manipulated at the molecular level, nanomaterials exhibit novel properties and functions that differ from their conventional counterparts, such as micron suspended or dissolved materials (National Nanotechnology Initiative, 2007).

  • Source Control of Microconstituents (September 2007) (Members) (Nonmembers)
    This TPU provides information on potential source control measures to reduce the presence of microconstituents in surface water bodies. Source control measures seek to reduce or eliminate pollution where it originates to protect various environmental matrices, including surface water bodies and groundwater aquifers.

  • Sources of Microconstituents and Endocrine-Disrupting Compounds (July 2007) (Members) (Nonmembers)
    This TPU describes the large number of naturally occurring and manmade compounds including household chemicals, personal care products and pharmaceuticals, flame retardants, additives to plastics and packaging materials, veterinary medicines, industrial chemicals, and pesticides. It identifies challenges and future directions for scientific study to better understand the effects of these compounds and ways to decrease these sources from entering the environment. 

Other Resources  

(Free resources for both members and nonmembers)