Our mission is to end the pollution of Lake Atitlan to benefit the health, culture, and economy of the people who live on its shore.
Lake Atitlán has no visible outlet, that is, it is an endorheic lake. Endorheic lakes are more sensitive to pollution; what goes into the lake, stays there. Decomposition takes many many years.
How is the Lake Dying?
In 2009, after years of increasing pollution, an environmental event stunned local residents, brought global media coverage, sharply curtailed tourism, and raised serious questions about the health of the lake. The nearly three month "bloom" caused 38% of the lake to be covered in putrefying cyanobacteria or blue-green algae.
Scientists from Guatemalan and American universities concluded after months of research that the influx of raw sewage was killing the lake.
Their 2014 report described the phosphorus and nitrogen in human waste which enriches the algae to the detriment of other plants and fish. This results in oxygen depletion, fish kills and will eventually cause eutrophication or death of the lake. Researchers found that after many years of nutrient enrichment, the lake is no longer able to recover. They predicted more "blooms" with increasing frequency unless the influx of sewage with its nutrients is stopped. In years since there have been minor blooms each year and a greater one in 2015 that covered 70% of the lake. (Return to Home Page)
Link to the 2014 State of the Lake Report: https://www.amigosatitlan.org/sites/default/files/stateoflake-20149abril.pdf
Link to the Scientific Report:
https://amigosatitlan.org/sites/default/files/reportecientifico-en-.pdf
For the first time in 2015, routine water tests detected a type of cyanobacteria that has the potential to produce toxins associated with health risks to humans. These are in addition to the pathogens found in untreated sewage. Local medical reports confirm the high occurrence of dysentery, diarrhea and gastric complaints among the population relying on the lake for drinking water. (Return to Home Page)
During the first major "bloom" in 2009, local people tried to clean the lake to bring back its health. The first bloom covered 38% of the lake's surface, the second in 2015, 70%. The algae was up to 20 meters deep. Scientists predict larger and more frequent blooms.
What do water tests show?
Until 2016, Amsclae monitored the lake's eleven functioning wastewater treatment plants that serve 9 of the 12 communities. The largest town served and the departmental capital, Sololá, has 64,000 residents while the smallest served, Santa Utitlán has a population of fewer than 1000. The remaining three smaller rural communities lack treatment plants and are served to varying degrees by septic systems, latrines, and dry toilets.
With the change to local control, Amsclae no longer publishes test results. The last results posted (2016) indicate that only one treatment plant, serving the village of Santa Catarina Palopó, met six of the nine required federal standards for treated wastewater; four plants met between three and five standards and the remaining four plants met no more than two each.
All of the plants fell below the coliform/ecoli standard which means after treatment all eleven water samples contained fecal material beyond the limits allowed. The water released by all plants into the lake is essentially untreated. While government water tests are no long available, private testing results reveal litle change in water quality. (Return to Home Page)
What is the wastewater treatment process?
Sewage collection and treatment in developed countries is typically subject to local, state and federal regulations and standards.
The goal of treating wastewater is to produce an effluent that will do as little harm as possible when discharged to the surrounding environment.
Sewage treatment generally involves three stages:
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Primary treatment consists of temporarily holding the sewage in a quiescent basin where heavy solids can settle to the bottom while oil, grease and lighter solids float to the surface. The settled and floating materials are removed and the remaining liquid may be discharged or subjected to secondary treatment. Some sewage treatment plants that are connected to a combined sewer system have a bypass arrangement after the primary treatment unit. This means that during very heavy rainfall events, the secondary and tertiary treat-ment systems can be bypassed to protect them from hydraulic overloading, and the mixture of sewage and storm water only receives primary treatment.
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Secondary treatment removes dissolved and suspended biological matter. Secondary treatment is typically performed by indigenous, water-borne micro-organisms in a managed habitat. Secondary treatment may require a separation process to remove the micro-organisms from the treated water prior to discharge or tertiary treatment.
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Tertiary treatment is sometimes defined as anything more than primary and secondary treatment in order to allow release into a highly sensitive or fragile ecosystem (estuaries, low-flow rivers, endorheic lakes like Atitlán). Treated water is sometimes disinfected chemically or physically (for example, by lagoons and microfiltration) to remove pathogens. For complete text: https://en.m.wikipedia.org/wiki/Sewage_treatment. (Return to Home Page)