Environmental science in service of the poor: The science behind Green Kalinga

(Part 1 of 2)

Many Filipinos are aware of Gawad Kalinga’s work in rebuilding the nation through a holistic program that includes housing, education, livelihood, health care, building a Filipino brand, social entrepreneurship, community building, and social innovation. The success of GK’s development model has been recognized worldwide, more recently with the 2011 Skoll Foundation Award. The development model (why and how does GK work?) has been the subject of studies by management and social scientists, including academics from Harvard University and UC Berkeley, among others. What is less known is the natural and environmental science behind some of these programs. In this article, we examine the science and engineering behind GK’s environmental arm — Green Kalinga.

Green Kalinga’s philosophy is that saving the environment and saving the poor are mutually reinforcing goals. This philosophy makes sense: the poor are often the most affected by environmental upsets and disasters; and the poor, being the most populous sector in a developing country, potentially have the most positive impact on the environment. 

Currently, Green Kalinga has programs focused on five areas: infrastructure design, energy, waste management, water, and greening. Because of GK’s scale (more than 100,000 homes nationwide), any advances leading to cost-savings and increased efficiencies in these areas have substantial effects on GK’s communities and residents. The goal is to use currently available and appropriate best technologies within the GK framework of economic, environmental, and social sustainability. Each innovation incorporated in a GK community is designed to address a specific environmental challenge, with a focus of integrating with other innovations and practices to create sustainable communities. Sometimes, more basic research and development are needed, and Green Kalinga is willing to form partnerships to allow R&D. Some of the innovations that are currently being incorporated in GK villages are described below.

1. Infrastructure design. To lower the internal temperatures inside GK homes, Green Kalinga has advocated a subtle change to the traditional GK house design: passive air vents. Low air vents allow cool air to enter the structure, while louvers closer to the ceiling allow hot air to exit. This allows a natural, passive air circulation system to develop. In addition, cool roofs painted with lighter colors allow for increased reflection of solar energy. Skylights have already been incorporated to take advantage of natural light, thereby decreasing the need to use artificial lighting when activities are held during the daytime. The use and planting of natural and renewable construction materials (e.g. bamboo) have also been explored to reduce carbon emissions related to transporting the materials to the build site.

2. Water and Sanitation. Green Kalinga has several innovative programs in water and wastewater management. To address stormwater runoff issues, GK has used stone pavers instead of impermeable concrete for walkways and other common areas. Stone pavers allow stormwater to infiltrate the ground, which has several benefits. First, this allows recharging of groundwater aquifers, instead of diverting water to surface water bodies. As it is, Metro Manila is sinking due to massive over-extraction of groundwater. Second, increased water infiltration and percolation also prevents the alteration of the natural hydrograph associated with the watershed. Impermeable surfaces reduce the time to peak, and increases the magnitude of the peak of the surface water hydrograph, resulting in increased flooding. 

GK has also pioneered the use of rainwater harvesters in several villages. Rainwater is a relatively clean water source, particularly if the first flush (first few minutes of rainfall) is not collected. Using rainwater reduces the amount of treated water needed for non-potable uses. Rainwater harvesting also decreases the incidence of flooding, because of increased storage. GK has installed plastic rain barrels and centralized cistern tanks for rainwater collection, and the most typical use is for toilet flushing and gardening.

An increasing number of GK villages now use the Anaerobic Baffled Reactor (ABR) technology, replacing the standard septic tank for treating domestic wastewater. The ABR allows for better solids settling, resulting in a higher solids retention time, and a more complete anaerobic degradation of solids. A slightly higher hydraulic retention time also encourages more complete conversion of the biochemical oxygen demand (BOD) in the wastewater. A single ABR can treat wastewater from several houses, as opposed to the one or two-family septic tank. In places where a more concentrated wastewater is available (e.g., from livestock waste), GK has installed anaerobic biogas digesters. In these bioreactors, organics are converted to methane by anaerobic microorganisms as part of a microbial food web. The methane produced can then be collected and used for cooking (and in theory, to electricity). 

Another treatment process that has been installed in several GK communities is the reed bed system. Essentially an engineered constructed wetland system, reed beds use microorganisms attached to soil and plant roots to convert BOD to carbon dioxide. The plant roots provide attachment surfaces and microenvironments with increased dissolved oxygen for the microorganisms. There is also evidence of increased nutrient (nitrogen and phosphorus) uptake through the plant roots, as well as through microbial transformations in the subsurface. 

(To be concluded)

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Francis L. de los Reyes III is an associate professor of Environmental Engineering at North Carolina State University. He conducts research and teaches classes in environmental biotechnology, biological waste treatment, and molecular microbial ecology. He was a Balik-Scientist of the DOST, and is a TED Fellow and a GK volunteer in North Carolina. He is a member of the Philippine-American Academy of Scientists and Engineers. E-mail at [email protected].

Jerick T. Limoanco is the former program head of Green Kalinga, GK Global Headquarters. He has an AB Psychology degree from Ateneo de Manila and is currently completing his Masters degree in Environmental Management from the same university. E-mail at [email protected].