hugo fernando palacios gonzález. introduction hydrologic resources in mexico 780 mm of pluvial...
TRANSCRIPT
Waste Water Treatment in Mexico
Hugo Fernando Palacios González
IntroductionHydrologic resources in Mexico
780 mm of pluvial precipitation (1 532 million m3)
Superficial runoffs of an annual average volume of 410,164 million m3.
Runoffs distributed in 320 drainage basinsSome of the most important rivers: Yaqui,
Lerma-Santiago, Balsas, Bravo, Pánuco, Grijalva, Usumacinta.
Yaqui Bravo
Lerma Grijalva
Water distribution problem- 80% of hydrological resources under 500 m (over sea level). 70% of total population over this level, 80% of industrial activity as well.
55% of industrial activity is developed in the valley of Mexico at more than 2000 m over sea level.
Water Quality3 main pollution sources classified as follows:Social sector. Mexico 23%, Monterrey 4.1%,
Guadalajara 4%. Only 50% of the population has sewerage infrastructure.
Industrial sector. Generates 43% of waste water in the country.
Agricultural sector. 92 500 million m3 are used in this sector. Produces 12% of waste water. Water with high levels of particles in eutrophication state.
Waste Water Treatment361 municipal WWT plants. Installed capacity
of 25 m3/s. (Unfortunately they only have capacity to treat 24%)
282 industrial WWT plants. Capacity of 20 m3/s. (Only treats 25%)
It’s been estimated that only 50% of these plants operate regularly
There’s an index of water quality used by scientists to classify treated water.
It’s known as the ICARen (Índice de Calidad de Agua Renovada) which would literally mean Quality Index of Renewed Water
ICARen of 0- drinkable waterICARen >38- useless water
ICaren Uses
<3 Drinkable water
16 Industrial: vapor production
22 Industrial: Cooling
25 Fishing
26 Recreation: swimming
26 Commerce, Services, industrial processes
27 Livestock
28 Agriculture
30 Municipal, undrinkable
34 Agriculture: plantations and vines
35 Agriculture: Industrial crops/ Green areas
36 Recreation with secondary contact: navigation
38 Not recommended for use
Water Purification StationsConventional treatment methodsBasic Physical and chemical procedures, such
as decantation, sedimentation and coagulation
Elimination of wastes, oils, greases, sandElimination of inorganic and organic
materials by decantationElimination of biodegradable organic matterStabilization and disposition of sludge
extracted in the processes
Reverse OsmosisMembranes made out of synthetic materials
CoagulationAddition of electrolytes (Alum or Lime)Charged particles of waste water combine
with ions neutralizing the chargesThe neutral particles combine to form greater
particles E.G. Ca(OH)2 -> Ca(aq)
2+ + 2 OH-
(causing pH change)
FlocculationUse of starch or multiply charged ions to
attract or trap the particles and settle down together.
Other salts such as iron sulfates Fe2(SO4)3 and FeSO4, chromium sulfate Cr2(SO4)3, and some special polymers are also useful
SedimentationUsed after coagulation and flocculationA settling tank with inlets and outlets is usedThe settled particles and sludge must be
removed
Settling tank
FiltrationRemoval of solids from water, passing them
by a porous mediumArtificial membranes, nets, sand filter and
high technological filter systems
AerationMain purpose: OxygenationRemoval of volatile organic substances ,
hydrogen sulfide, ammonia and volatile compounds
Diffused aeration- air bubbles through waterSpray aerationMultiple tray aeration- water flows through many
trays to mix with airCascade aerationAir stripping- combination of multiple tray and
cascade techniques
BioaugmentationIntroduction of a group of natural microbial
strains or a genetically engineered variant
KB-1 Dechlorinator.Used to introduce Dehalococcoides to sites where they are absent
Activated SludgeAtmospheric air or pure oxygen is bubbled
through sewage combined with organisms to develop a sludge, which reduces the organic content of sewage.
Industrial Effluent RecyclingClonal poplar as recycling engineTranspiration function driven by weather
characteristicsPlantation supplied with water according to needsMonitoring of parameters every 10 minutes:1. Solar radiation2. Air temperature3. Air relative humidity4. Wind speed5. Rainfall
Parameters monitored by a station equipped with a micrologger (environmental data logger)
Data is retrieved and evapotranspiration is calculated for every 10 min. interval
These amounts are summed until they reach the amount of a watering (Pre-established based on soil water)
Poplar plantation
Effluent recycling plant
Sewerage InfrastructureOld infrastructural designsOld facilitiesNew Projects:“Túnel Emisor Oriente” (Mexico city). Interior
diameter of 7 meters. Extension of 62 kilometers at more than 200 meters under ground level. Investment of 13 million pesos (19.5 million Kč approximately). Avoid Future floods.
Present Day ProblemsIn the Valley of Mexico only about 6% of their
waste water is treated (against legislation)Immediate response to the problem:1. Permits for the construction of 6 new WWT
plants in Mexico city2. Investment of 37 million pesos (55.4 million
Kč approx)
Leading WWT companiesACS Medio Ambiente (Monterrey, NL)Aguas Latinas México S de RL de CV
(México, DF)Alianza con la Biosfera (AliBio) (México, DF)Bio-Ingenieria Ingeniería SA de CV (La Paz,
BCS)
References www.sagan-gea.org/hojared_AGUA/paginas/
8agua.htmlhttp://www.imacmexico.org/ev_es.php?
ID=17461_201&ID2=DO_TOPIC