Review of Sustainable Water Resources in the Built Environment by Marilyn Waite

Sustainable Water Resources in the Built Environment is the product of Marilyn Waite’s senior thesis at Princeton University, Princeton, New Jersey. It draws from two case studies carried out on two different continents: Panama in South America and Kenya in Africa. The primary focus of the book is on the opportunities, feasibility, and constraints in implementing low-cost sustainable water resources and sanitation solutions in the built environment in two different communities: Smithsonian Tropical Research Institute (STRI) in Bocas del Toro, Panama, and Mpala Research Center (MRC) in Laikipia, Kenya. These communities are different for a number of reasons. The STRI is a research center built by a developing nation and hence benefits from high-tech green solutions, whereas the community around the MRC was constructed from local expertise using low-cost construction methods. Furthermore, Panama and Kenya have wet and dry climates, respectively, and have different levels of access to improved water sources and sanitation facilities.

The book is comprised of nine chapters and an appendix. In Chapter 1, the author argues that water is central to sustainable construction, especially in growing rural communities in developing countries in which water demand often exceeds supply. The objectives laid out by the author are “(1) to provide technical analyses of the water aspects of sustainable buildings in the two case studies in order to provide technical support for the feasibility of green buildings, and (2) to consider the policy implications of these sustainable practices.” The first objective is centered on rainwater harvesting and composting toilets, and the second is on the opportunities and challenges in implementing the proposed solutions.

In Chapter 2, the author discusses the water aspects of sustainable buildings, focusing on rainwater harvesting and the quality and suitability of the collected water for domestic purposes. The wastewater aspects of sustainable buildings is discussed in Chapter 3. The wastewater systems in use in Panama and Kenya are discussed. In Panama, septic tank systems, wastewater stabilization ponds, phytoremediation, and constructed wetlands are commonly used, whereas in Kenya, the ecological sanitation (EcoSan) and eco-toilets, such as Fossa Alterna and Arborloo, are employed. Ecological sanitation, unlike septic tanks, has the advantage of converting excreta through composting into a fertilizer, which may be used in agriculture.

Chapter 4 provides a description of STRI. Ironically, the residents of STRI have access to a municipal water system, but the piped water is not suitable for consumption, and bottled water fountains have been installed for domestic purposes. Elaborate rainwater collection and treatment was included in the project. The author describes the system through an extensive collection of pictures and schematic diagrams. The treatment process is elaborate and comprises sand filtration, active carbon filtration, micron filtration, ultraviolet disinfection, and chlorination for water that is stored for later use. Wastewater is currently discharged in a system of septic tank and drain fields. A combination wastewater stabilization pond and constructed wetland is planned for the future. Details of the proposed system are provided.

Chapter 5 describes the water quality experiments that were conducted at STRI. Tests were effected on the rainwater running from the roof during storms into storage tanks and in the overflow pipes and on municipal water from the tap. Parameters tested included total suspended solids (TSSs), turbidity, pH, sulfates, color, nitrates, nitrites, and total and fecal coliform.

A description of the site in Kenya and water management practices in the village homes near MRC is given in Chapter 6. The author gives a brief description of the climate and water demand and availability in Kenya and discusses the source and uses of water in the area surrounding MRC. The Mpala area is home to 510 people, and the residents use streamflow stored in dams for general cleaning and rainwater for consumption purposes. The average daily rainwater consumption is $8\mathrm{L}/\mathrm{person}$. Rainwater is boiled and ceramic-filtered before consumption. The author compares thatch and corrugated iron roofs and notes that although the latter is better for rainwater collection, because it has a larger runoff coefficient and collects less particulate matter, it has the disadvantage of being more expensive and less suitable for a hot climate.

The water quality tests on the rainwater collected at the Kenya site are described in Chapter 7. The water was found to be contaminated from deposits on the roof, and the means to divert the first-flush in the collection system are discussed.

Chapter 8 describes the design of rainwater harvesting systems on the basis of climatic conditions at the MRC site. The type of roof and its runoff coefficient, rainwater estimates on the basis of different rainfall periods, sizing of storage tanks, the design of the gutter, and treatment options are discussed.

Chapter 9, the last chapter, gives a summary, conclusions, and policy recommendations on the basis of the material presented. The similarities and differences between the two study sites and the challenges of the two different climates are discussed, followed by a list of policy considerations for encouraging sustainable building practices.

The material presented in this book is on the basis of the author’s experience and is supported by an extensive literature review. The book will be a good addition to the library of practitioners working in the field in developing countries or engineers entrusted with the design of sustainable infrastructure in developing communities. The list of references consulted by the author can also be a good starting point for anyone interested in replicating or pursuing the research conducted by the author. The author should be complimented for bringing out real-world water situations in Kenya and Panama.