New Wastewater Book Balances Environmental Ideals and Low-Income Realities
Wastewater Irrigation and Health: Assessing and Mitigating Risk in Low-income Countries
Edited by: Pay Drechsel, Christopher A. Scott, Liqa Raschid-Sally, Mark Redwood and Akiįa Bahri
Paperback: 432 Pages, $55.95
Publisher: Earthscan Publications
Poor countries that aim for top-notch water quality often end up with unmanageable water-quality schemes. A new book, “Wastewater Irrigation and Health: Assessing and Mitigating Risk in Low-income Countries”, aims to help policymakers balance high ideals with economic realities.
28 July 2010 |
The disability-adjusted life year (DALY) is a measure of overall disease burden
developed by the World Health Organization
. It adjusts the potential years of life lost due to premature death
by adding a disability or poor health term. This combines mortality
. The formula is:DALY = YLL + YLD or “disability-adjusted life year = years of lost life + years lived with disability”
“The perfect is often the enemy of the good.”
If the appropriate technology movement
had a tagline, that would probably be it. Designed specifically for low-resource settings and with appreciation for simplicity, low maintenance and ultra affordability, appropriate technology wastewater irrigation focuses on 80/20 solutions that are 'good enough' for the particular local ecological context to which they are applied.
The use of wastewater for the irrigation of crops is not a new technology; it has been around for millennia. In recent years, however, governments in low-income countries have tried, unsuccessfully, to control the use of wastewater for irrigation while implementing quality standards and levels of treatment that match those in developed nations. This sounds great in theory, but is wholly inappropriate for countries that typically suffer from issues such as extreme water shortage, waste management challenges, extreme population growth and limited availability of food.
The key drawback of the prevailing approach to wastewater irrigation is that it is a solution designed for environments where none of these issues are life-threatening and where the funding and political structures exist to implement comprehensive treatment solutions and planned uses of wastewater. This ignores the possibility that a greater good may be achieved in low resource settings by actively supporting treatment measures that are less than perfect
, but are accessible to the majority
and result in a tolerable additional disease burden.
The authors of Wastewater Irrigation and Health
are described in the forward as exactly the group of pioneers that are set to change this approach, and they deliver a well-framed discussion involving both policy-makers and practitioners on how the risks presented by pathogens present in wastewater can be both managed and mitigated, creating a platform from which progress can be achieved through appropriately designed technology.
Setting the Stage
of the book introduces the key drivers of wastewater irrigation as well as the core paradox to this discussion (namely, that while there are risks to using wastewater for agricultural irrigation, primarily associated with the consumption of uncooked vegetables, this is but one factor in a wider systemic problem).
Firstly, both water and nutrients are constrained resources in most low-income countries that are struggling to support ever-increasing populations. By ignoring the potential to close the water and nutrient loops, or by making it difficult for individual farmers to do so, governments are not only missing an opportunity to reclaim valuable resources from wastewater, but they are driving the practice underground and therefore failing to control it.
Secondly, the health risks presented by the practice of wastewater irrigation are difficult to ascertain exactly since poor sanitation and lack of access to clean drinking water create numerous exposures to pathogens such as E. Coli and Cryptosporidium. Rather than attempting to control the use of wastewater for irrigation, the authors recommend adopting resource reclamation practices (which could result in additional revenue streams if appropriate business models are identified) while also addressing wider educational gaps around sanitation, the food hygiene and the access to clean drinking water.
The Science Part
of the book centers on risk assessment and makes reference to the 2006 WHO Guidelines for the Safe Use of Wastewater, Excreta and Greywater
, which introduces the concept of there being an increased disease burden, in terms of Disability Adjusted Life Years (see sidebar, right), that is tolerable as a result of the use of wastewater irrigation.
The authors go on to present further risk assessment tools and practices that can be used to identify packages of treatment activities that operate within this tolerance, followed in Part Three
by discussion of the specific treatment measures that can be employed for the treatment of wastewater as well as non-treatment solutions such as extraction of biosolids and nutrient recovery.
Measures are well presented with data on both cost effectiveness and contribution to increased disease burden. It is also notable that throughout the presentation of these options for risk assessment and management a multiple barrier approach is suggested as preferable and that these are not end-state solutions, but serve to put communities on the path to the planned and controlled treatment and use of wastewater for irrigation along with the improvement in standards of safety that implies.
While both the risk assessment and mitigation measures form the main body of the book, Part Four
goes beyond the science and focuses on the governance and adoption challenges that arise from the implementation of these risk reduction strategies. The authors have correctly identified that there are significant behavioral and cultural issues at play with respect to this subject, and there are a large number of stakeholders that will need to be engaged if an administration is going to be successful in implementing solutions of this nature.
This holistic approach is evident in "Facilitating the Adoption of Food Safety Interventions in the Street Food Sector and on Farms". Here the authors deal with how the success of innovations in wastewater management rely on cultural sensitivity and the understanding of 'external behavior determinants' when designing sanitation and hygiene interventions. For example, the authors cite a number of cases in Ghana where the public respond to messages that promote neatness, cleanliness and prestige with respect to food safety and sanitation interventions, and care less about the health benefits. Specifically in relation to street vendors, these business owners are driven not by their knowledge and education, but by the public perception of the cleanliness of the product they offer. Successful campaigns leverage these social pressures to promote the adoption of interventions rather than attempting to overcome them solely through programmatic approaches.
Closing the Loop
Overall, the editors have structured the flow of the material very logically and crucially have taken care to provide a solid foundation and taxonomy in the opening chapters that frames the remaining material. This lends an element of accessibility to what at times is very detailed coverage of epidemiology, statistical risk assessment and management methodology and some of the salient governance and behavior change challenges associated with public health and sanitation interventions. This book provides great insights into appropriate solution development for anyone interested in closed loop or cradle-to-cradle design and presents an approach for how to apply these concepts to a complex and culturally sensitive topic.
Colm Fay is a dual MBA/MS student at the University of Michigan's Erb Institute for Global Sustainable Enterprise http://www.erb.umich.edu/ specializing in Environmental Policy and Planning, in particular market based approaches to conservation, land stewardship and poverty alleviation.
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