Taking Better Care Of Our Water
Categories: Tips & Tricks
The control of water resources has been politicized and used as a figurative weapon of war at the international level --- as illustrated by the withholding of water-treatment resources and technologies under the United Nations trade embargo against Iraq in the 1990s. This control has been used already by the Untied States and the United Kingdom as a means to weaken Saddam Hussein and Iraq. Under UN sanctions, 1.5 million Iraqis (including approximately 565,000 children) had died as a result of the embargo by the mid-1990s, which included withholding "vital goods" such as chemicals and equipment to purify drinking water and to treat sewage, according to UN aid agencies UNICEF and UN FAO.
Today in the post-invasion Iraq now being occupied by the United States, the water infrastructure has not been rebuilt. Many communities are still without clean drinking water and sewage treatment. Raw sewage still flows in the streets of many cities, and large segments of the population rely on water trucks to procure clean drinking water.
Why was Iraq so vulnerable to UN sanctions? It turns out that Iraq's water-purification and sewage-treatment infrastructures are conventional: they use chemical- and fossil-fuel-guzzling technologies similar to those used in the United States and other industrialized countries. If Iraqis had built their water systems using ecological and natural designs and principles and technologies, then they could have become independent of imported chemicals and parts --- and consequently prevented the deaths of 1.5 million children and adults from otherwise easily preventable waterborne diseases.
Why Natural, Small, and Decentralized Systems?
The lessons of Iraq are valuable for many communities and nations: Despite its oil wealth (second only to Saudi Arabia in underground reserves), Iraq could not import the necessary replacement parts and chemicals for its water treatment plants because of the economic and trade sanctions. Indeed, conventional water systems are only as strong as the weakest link in the overall raw-materials-sourcing, manufacturing, transportation, and delivery infrastructure.
The case for small, decentralized, and natural water systems is the same as that for the food system: many experts have advised us to go back to local farms, to be self-sufficient on a local level. These natural systems use local materials and resources, local labor, and local expertise, thereby making them independent of costly and highly toxic synthetic chemicals and fossil fuels in their operation.
Conventional Systems v. Natural, Ecological Water Systems
In general, ecological treatment systems are land- (or space-) intensive and more time-consuming, while conventional systems are energy-demanding and resource-intensive. Conventionally engineered and resource-intensive water-treatment systems are almost useless when lacking key chemicals and fossil fuel.
These systems are small, low-cost, decentralized, energy-efficient (and can be operated independent of fossil fuel), and community self-sufficient; they can be built, operated, and maintained using local labor and resources in the communities.
Many natural systems are widely in use, including the following:
- Ponds (e.g., aerobic, anaerobic, aerated, facultative, waste-stabilize, primary, secondary, tertiary, maturation or polishing, algal, duckweed, and macrophyte ponds, etc.)
- Constructed wetlands (e.g., subsurface, surface flow, vertical flow) and reed beds
- Anaerobic digesters
- Aquaculture and aquatic-macrophyte pond system
- Sand filters (slow sand filters, fast sand filters)
- Low-cost sorbents and filters (e.g., coconut shell, peanut hull, risk husk, peat moss, iron-oxide-coated sand, old clothing, clay, zeolite, etc.)
- Integrated, combined systems (a full system with many components discussed here)
As there are many other types of experimental systems being tested by researchers around the world, we will only focus on ponds, the lowest cost and easiest to construct of all natural systems, in this essay.
Ponds in Sustainable Ecological Wastewater Treatment: Simulating Nature's Processes of Degrading Wastes
Ponds have been characterized as a "low-tech" and "old-fashion" method of sewage treatment. Despite their deceptively simple appearance -- resembling a hole in the ground filled with wastewater -- ponds are actually complex and dynamic ecosystems with untold trillions of microorganisms forming numerous intricate food chains suspended in the water column, inhabiting pond sediments, and attaching to various surfaces in the pond.
The organisms in the ponds include bacteria, viruses, protozoa, zooplankton, phytoplankton, algae, fungi, rotifers, insects and insect larvae, crustaceans, worms, shrimps, snails, fishes, and plants, among thousands of species of organisms. Numerous sequences of chemical, biological, physical, and biochemical reactions and processes occur within the ponds during the time wastewater is in the ponds. Ponds are far more complex than any other waste-treatment systems designed and engineered by human beings. Although reactions and processes occurring in the ponds are difficult to model, all types of wastewater-treatment ponds are relatively easy and inexpensive to design, construct, operate, and maintain.
Ponds are a low-cost and environmentally sustainable technology for wastewater treatment in developing countries, but they are not commonly used in industrialized countries, except in small rural and remote communities. Various researchers have estimated that the United States had about 7,000 pond systems in 1975; Canada 868 ponds in 1981; and France, approximately 1,800 ponds in 1987 and 2,500 in 1993 in small, rural communities. In France, lagoons represented about 26.9% of 976 very small municipal wastewater-treatment plants for communities with fewer than 2,000 population equivalent (p.e.), and in Bavaria, Germany, more than 1,500 rural communities each with fewer than 5,000 people, use ponds for wastewater treatment.
Scientists generally recognize that four major biological and biochemical processes occur simultaneously but at different zones in wastewater ponds: microbial aerobic and anaerobic biodegradation and biotransformation, photosynthesis, and sedimentation. Other reactions and processes also occur: predation on bacteria and other microorganisms by rotifers and zooplankton, fermentation of settled solids and sludge at pond bottom (in which biogas, comprising 65 percent methane, is generated), pH shifts in pond water, algae exuding algal toxins that eliminate pathogenic microorganisms (e.g., fecal coliforms), and many other processes.