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Planning and Installing Sustainable Onsite Wastewater Systems is a meticulously detailed guide to residential and small-scale commercial onsite wastewater treatment systems.
Written by a professional engineer with extensive experience with onsite wastewater treatment systems, this comprehensive guide covers wastewater treatment system planning, permitting, design, and construction. Clearly written text is accompanied by step-by-step illustrations with detailed explanatory captions.
Planning and Installing Sustainable Onsite Wastewater Systems provides practical information on options that have proven to be the most sustainable and cost effective on a long-term basis, and to have long service lives when properly built and designed. This book fills the gap left open by the general reports and articles on wastewater treatment systems.
From the Foreword
Water management scenarios have been dominated by either a centralized collection, treatment, and discharge model or an individual septic tank as a temporary solution model. This is changing. Receiving waters accepting treated sewage are compromised, and soil-based systems are becoming increasingly adapted to the use of a limiting constituent model in permitting and design.
The land limiting or LDP approach described in this work provides practitioners at all levels with sound tools to better site, size, design, install, operate, manage, and maintain onsite and decentralized waste- water systems as the permanent and essential element of the waste- water infrastructure they represent. These land-based systems have been utilized for over 100 years, mostly in rural areas. That model is changing. Today, these systems are utilized increasingly in suburban and urban fringe areas in part because of limitations associated with receiving waters.
Do we know all there is to know regarding this decentralized infrastructure, all we need to know about soil loadings and retention times to achieve pollutant removals in the plant soil system? Probably not. Do we know about assimilative capacities in receiving streams? Probably not, and that has not stopped installations of centralized infrastructure with associated stream discharge.
This book provides a rational model for assessing assimilative capacities of soil systems, and this model should serve as a foundation for effective rules and regulations to enable the better use of decentralized systems.
These days project managers have to be something no other team member is: the "inspired generalist." Whether an architect, engineer, or construction manager, the inspired generalist is the team member who must know a good deal about almost everything being built or installed into a successful construction project. In these days of specialists for everything from low-voltage wiring systems to waste management, it is imperative that there be a symphony conductor who can bring it all together so that the result is a system of complimenting parts. As architects and engineers move into project management, positions, and situations where coordination of various elements of small and large projects is needed, it's important that there be an understanding of some of the concepts that are fundamental to sustainable wastewater systems planning and implementation.
This book is a "must have" for persons wanting a practical reference guide for designing and constructing decentralized systems, including the inspired generalist. I know of no other book on this subject that so effectively links essential scientific principles and practical design and construction details needed for sound and sustainable systems. The author breaks down a very complicated and complex subject into bite-sized chunks of useful information that is logically laid out and easy to absorb - whether it be for the construction sciences student, design professional, permit reviewer, or construction project manager. Unlike what we often end up finding when we do Internet searches for information on a particular subject, what's presented here is not "naïve source knowledge." It is real, accurate, and vetted thanks to the author's important combination of deep subject-matter knowledge, education, and many years of relevant practical field experience.
The book presents many complex scientific principles integral to sustainable wastewater planning in a way that's accessible for practical application. The many photo illustrations of methods and materials for construction help greatly to inform the reader. Most college texts and professional books don't adequately link academically based technical information with step-by-step practical information needed to implement those concepts in a sound manner. The book is also written so that the basic concepts are understandable to persons not necessarily having significant technical training in these areas of science and engineering.
While it's clearly impossible to anticipate and evaluate all of the constantly evolving decentralized wastewater systems, the book walks readers through a logical progression of explanations for key factors to consider relative to their long-term sustainability. That same basic approach can be used for comparing new technologies and processes as they appear on the market and become available for consideration. The comparative tables presented in several of the chapters are very helpful as quick reference guides. The consumer-style rating of wastewater treatment processes commonly employed
for decentralized systems in Chap. 6 serves as a very good tool for making basic comparisons of system types in a wide range of settings and conditions.
Last, but not least, the inspired generalist has to have the ability to be creative when attacking the inevitable project challenges. To that end, the examples included in the final chapter of the book present a diverse array of projects and site conditions that promote creative thinking about the use of natural treatment processes and recycled materials that compliment the very important notion of "sustainable" architecture and development.
From the Preface
Engineers and project planners dealing with decentralized, or "onsite," wastewater systems are routinely asked by property owners how to choose the most suitable and cost-effective systems. Complete answers to those questions are often fairly complex, and based on a wide range of engineering principles and science spanning several technical disciplines. Most engineers leave their formal training in engineering colleges without having had the diverse training needed for designing sound and sustainable decentralized systems of varying sizes and in differing geophysical conditions. As the body of knowledge within each technical discipline increases, we see more and more specialization among scientists and engineers, making it harder for practitioners to obtain the training and experience needed to keep up with multiple specialized areas within each major discipline. Even within a single major technical discipline such as civil engineering, persons having a thorough understanding of and high level of competence with larger centralized wastewater systems typically don't keep up with methods, materials, and state-of-the-art industry practices applicable to small- to midsized decentralized waste-water systems.
Questions from property owners and developers often focus on the merits and cost-effectiveness of obtaining centralized service, if available, versus implementing an appropriate decentralized waste-
water solution. While many of the basic scientific principles routinely used for municipal-scale wastewater systems are applicable to small-scale systems, methods and materials found to work most effectively for smaller-scale systems are often quite different from those used successfully for large-scale systems. It usually takes many years of practice for engineers and planners to be prepared to help guide project owners with implementing the most sound and cost-effective wastewater service approaches.
Onsite, or decentralized, wastewater treatment systems industry practices around the world have tended to evolve based on a mixture of local geographic, socioeconomic, educational, and cultural conditions. In geopolitical areas where rules are in place for the design and construction of those systems, such rules have often developed around empirical observations and local influences, including design practitioner familiarity with and bias toward certain methods and materials. Rules and practices are also often greatly influenced by vendors of certain products lobbying for a significant share in local markets.
Larger municipal-scale wastewater systems in the United States and many other countries have historically been much more strongly influenced by nationally and internationally vetted sources of information for their design, construction, and management. University/college engineering programs and other wastewater industry educational curricula guiding the implementation of larger centralized systems tend to draw upon a fairly well-organized body of scientific research and literature on a myriad of wastewater treatment systems issues. It is not surprising to find more "centralized" bodies of technical information for larger-scale wastewater systems since they serve population centers around the world. In that most centralized wastewater systems discharge to streams/rivers and surface water bodies, with potentially direct impacts on downstream users of those water supplies, they are somewhat analogous to other large interconnected utility grids. National and international organizations have evolved over time that identify research and funding needs for these systems, direct those research efforts, and help federal, state, and local governments with education and information dissemination on industry design and construction practices.
Potential impacts to the surrounding environment from decentralized systems applying effluent below the ground's surface tend to be much less visible and are harder to track than those from systems using direct surface discharge. For systems relying on final land/soil disposition of wastewater effluent, consideration of the character of local conditions is obviously critical to effecting sound design and construction practices and accompanying rules. However, due to the more localized focus and distributed character of onsite wastewater systems, they have tended to be disadvantaged with fewer organized sources of funding for research and education. Relatively few college engineering curricula devote appreciable time and resources specifically to decentralized wastewater systems coursework. Absent that formal specialized training, engineers/designers dealing with those systems tend to (1) design smaller-scale systems in ways consistent with their formal training on municipal-scale wastewater systems, (2) rely primarily on state or local rules to guide their practices, which in most cases are essentially minimally applicable standards, (3) rely largely on manufacturers' technical representatives dealing with certain product lines, or (4) strive to educate themselves on methods and materials more suited to decentralized systems. In practice, onsite systems designs are usually the product of a combination of two or more of those influences.
Even though the best engineers and designers seem to be those who spend appreciable time at construction sites for their systems, very few owners of small- to midsized decentralized wastewater systems can or are willing to pay for engineers/designers to spend much time at the site during construction. The result is that most onsite systems designers tend to spend a fairly limited amount of time at those construction sites, and often only the minimum number of visits to satisfy regulatory permitting requirements. With most onsite systems components located below the ground's surface, and piping, valves, and other critical elements often already buried when the system designer goes to the site to make any obligatory checks, there .are limited opportunities for most designers to observe the "devil" that creeps into many of the details. Photo illustrations of actual systems installations included in this book will hopefully be of help to systems owners and others for participation in the oversight of their projects during construction.
Much of the body of science and engineering practices associated with large municipal-scale land treatment systems is directly applicable to small onsite/decentralized wastewater systems. In recognition of the important role that natural land treatment processes play in the implementation of more cost-effective and well-performing domestic wastewater systems, the U.S. EPA, the Water Environment Federation, and other entities have researched and compiled a number of excellent technical resources on that subject and on natural treatment processes in general. Those books, design manuals, and many technical guidance documents and articles offer a very well-founded and logical design approach, and are used in many college/university courses covering larger-scale land treatment systems.
This book is, in large part, intended to help bring together those two worlds: the more centrally organized body of technical information developed for larger municipal-scale domestic wastewater systems, and the more diffuse and widely distributed world of small- to midsized decentralized systems. The land-limiting constituent (LLC) or limiting design parameter (LDP) concept was presented several decades ago in the context of larger systems using land/soil disposition of wastewater effluent. In graduate engineering school at the University of Texas - Austin, I had the good fortune to study land treatment processes under Dr. Raymond Loehr, one of the leading experts on applying LLC concepts to the design of sound and sustainable land treatment systems. In later years, through both research and design work, I gained increasing appreciation for the relevance and importance of those basic land treatment engineering concepts.
Each of us tends to build upon and benefit from the experience of others, and time in the field with good contractors has offered many opportunities to learn details that could not possibly have all been covered in even the best of installer training programs. Work on a number of decentralized systems demonstration projects has also offered invaluable insights into the pros and cons associated with the use of certain methods and materials. Several chapters in this book cover details of construction for certain types of systems that may or may not be included in training programs for installers, and would almost certainly not be covered in educational curricula for engineers/designers. While frequent visits to construction sites should, in my opinion, be an essential element of all engineers'/designers' professional practices, it is hoped that imparting some of that field experience here can help prevent some lessons from having to be learned the hard way.
The chapters of this book have been organized to guide readers through a logical progression of concepts that build upon each other. The early chapters present sustainability considerations and planning concepts that apply to essentially all domestic decentralized wastewater systems. From there, chapters cover methods and materials starting basically from the building's sewer stub-out, progressing to treatment processes, and then to final effluent land/soil disposition. Summarizing tables are presented in several chapters that may be helpful for later referencing once the reader is familiar with the context of information presented. Because of the abundance of technical support available to industry practitioners for most proprietary treatment and dispersal methods, detailed design and construction information presented in several chapters is devoted to certain nonproprietary methods that are considered some of the most sustainable in use today. The last chapter presents several project examples intended to put previously discussed planning concepts together as they relate to specific geophysical and project conditions.
About the Author
S M Parten is a licensed professional engineer with over 25 years of experience researching and designing decentralized and centralized wastewater systems. Since 1992, Parten has owned and operated Community Environmental Services, Inc., a civil engineering firm specializing in the design and management of decentralized wastewater systems. In addition to authoring a number of technical articles, Parten was a member of the Water Environment Federation's Technical Committee Task Force for Natural Systems for Wastewater Treatment, developed Fact Sheets for onsite wastewater treatment systems currently referenced in the U.S. EPA's Onsite Wastewater Treatment Systems Manual, and was principal investigator for a nationwide Water Environment Research Foundation (WERF) study published in 2008 on the performance of large/community-sized decentralized wastewater systems in the United States. Recently, Parten has served as a consultant to onsite wastewater regulatory authorities in several U.S. states and territories, assisting with the development of improved standards and management practices.
Table of Contents
Chapter 1: Introduction. Chapter 2: Sustainability Considerations for Decentralized Wastewater Systems. Chapter 3: Project Planning and Site Evaluation. Chapter 4: Wastewater Collection and Conveyance Methods Chapter 5: Preliminary Treatment. Chapter 6: Secondary and Advance Treatment Methods. Chapter 7: Sand Filter Construction. Chapter 8: Subsurface Flow Wetlands. Chapter 9: Effluent Dispersal Methods. Chapter 10: Low Pressure Dosing Effluent Distribution. Chapter 11: Project Examples.
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