Mexican Experience in El Mezquital Valley M E X I C O. Blanca Jimenez

Transcription

1 Mexican Experience in El Mezquital Valley M E X I C O Blanca Jimenez

2 M E X I C O 2 million km 2 and 104 million Inhabitants 67% of the country is arid or semiarid Use of water in México

3 Water reuse in Mexico 171 m3/s of municipal wastewater are produced, from this volume 78% are reused, for Agricultural irrigation (86%) Municipal uses (6%) Industrial uses (8%) In 1995, irrigation was performed with untreated wastewater In 2005, 40% with treatment

4 Mexico City and the Mezquital Valley

5 Mexico City Water Supply 72.5 m 3 /s (21 million inhabitants) 16% Groundwater from other Basin 31% Rivers from other Basin Water Balance in Mexico City 7.7 m 3 /s Industrial reuse 21% Urban Reuse 45% N 60 m 3 /s Sewage 52.3 m 3 /s 53% Groundwater Local Overexplotation 8 m 3 /s Mexico Valley Aquifer 2240 masl El Mezquital Valley

6 BUT The actual deficit is of 7 m 3 /s and 10 m 3 /s will be needed for 2010 Reuse of Mexico city sewage 2 % Industries 6 % Municipal 5 % Ecological Uses 87 % to irrigate 85,000 ha in the Mezquital Valley since 110 years

7 Xochimilco chinampas (wetlands) filled with reclaimed water

8 Chapultepec recreative lake, filled with wastewater

9 Dust Control in the Texcoco Ex-lake, Mexico City

10 Description of Mezquital Valley Semi arid Climate (rainfall of 550 mm and evaporation of mm) The soils are saline very poor (low contents of nitrogen, phosphorous and organic matter) s the Government was thinking on moving people

11 Mezquital Valley with no irrigation

12 Mezquital Valley irrigated with raw wastewater

13 Yield Increase due to Wastewater Crop Untreated Wastewater Yield in Ton ha -1 Natural water % of increase Maize Barley Tomato Oats Chilli Alfalfa Wheat

14 Metal content, mg/l

15 Gastrointestinal diseases due to wastewater reuse Parasites Ages Morbidity rates Raw wastewater Natural water Ratio Ascaris lumbricoides (Helminth) 0 to 4 5 to 14 > Giardia lamblia (Protozoa) 0 to 4 5 to 14 > Entamoeba histolytica (Protozoa) 0 to 4 5 to 14 <

16 Ascaris

17 Gastrointestinal diseases mortality rates for children under five years old Country mortality rate/ inhab Poland 1 Romania 2 Chile 12 Mexico 17 Peru 34 South Africa 44 India 76 Pakistan 124

18 New regulatory framework NOM-001- ECOL-1996, Maximum Limits of pathogens in wastewater reused for agricultural irrigation 1 1 Helminth Ova for unrestricted crops and 5 restricted ones Fecal Fecal coliforms of 1000 MPN/100 ml

19 Wastewater Treatment To reduce Needs HO < 1 ova/l FC < 1000 MPN/100 ml but, Preserving BOD, N, and P Controlling salinity problem

20 CONVENTIONAL SCHEMES Primary Secondary Tertiary? TSS BOD $$$$$ N, P Reuse COMPACT SCHEMES Treatment for reuse Wastewater $ Reuse

21 Correlation TSS-HO in untreated Wasteater HE= TSS r 2 = TSS (mg/l) 87 Helminth eggs (He/l)

22 Wastewater Treatment for Agricultural Reuse Coagulant Advanced Primary Treatment Polymer (high weight and high charge density) Disinfection (Cl or Cl/UV) Flocculation-coagualtion coagualtion Grit removal Sedimentation Sand Filtration Effluent

23 Removal of pollutants during treatment Parameter Influent APT Filtration Disinfection Helminth Ova 90 3 <1 <1 Fecal Coliforms Salmonella ND Protozoan Cysts P. Aeruginosa ND TSS TKN TP COD

24 Treatment Cost Type of Treatment Capacity: 38 m 3 /s USD Advanced Primary Treatment + Filtration + Disinfection Activated sludge + Filtration + Disinfection For all cases, sludge stabilization using quick lime was consider - Disinfection been performed by a chlorination system

25 APTs in Mexico 80% for agricultural irrigation 25% of the total WW treated SITE Acapulco, Gro Ciudad Juaréz Culiacán, Sin Puebla San Pedro Atocpan, DF San Luis Potosí,, SLP WTP Flow, m 3 /s TOTAL

26 Ciudad Juárez, North 2500 L/s and South 1000 L/s

27 Water balance in the Mezquital Valley 38 m 3 /s Mexico City raw wastewater 5.2 m 3 /s extraction Since 1900 Tula Valley aquifer 38% agriculture 33 % industry 17% domestic consumption 12% other uses 25 m 3 /s infiltration from irrigation (13 fold natural recharge) 7.8 m 3 /s to other valleys High Irrigation rate combined with 688 km unlined channels for wastewater distribution

28 MEZQUITAL OR TULA VALLEY

29

30 < year 1900 the groundwater level was at least at 50 m below Since 1997, artesian wells with flows from 100 to 600 L/s Groundwater main source of drinking water of 500,000 inhabitants

31 Reuse of Excess Volumes of Well La Noria in Swimming Pools at Mezquital Valley, Mexico

32 Tezontepec Spring

33 Phase I Rapid assessment of the quality of the water been used to supply people in the Mezquital Valley

34 Preliminary water quality Assessment GROUP Inorganic compounds Organic compounds Physical Metals Non-metals Microbiological Organoleptic ANALYZED PARAMETERS Total 288

35 WATER QUALITY AT DRINKING WATER SUPPLY SITES IN MEZQUITAL VALLEY PARAMETERS Viruses Helminth eggs Acute toxicity (Microtox ) Pesticides Atrazine Carbofuran 2,4-D Other compounds RESULT ND ND ND ND < 0.5 ppb < 0.5 ppb < 0.1 ppb Chomatogram picks ND = NOT DETECTED

36 Results No main problems Water was light saline In wells built with no care some microbiological problem Why not using it for Mexico city supply?

37 Phase 2 To determine the quality in a number of representative sites of water supply systems for population ( inhab)

38 Location of sampling sites

39 EVALUATION OF DRINKING WATER SUPPLIES Parameter Sources not complying with drinking water standards % Number % Volume TDS Sodium Fecal coliforms Nitrates Chlorides Hardness 31 9 Sulfates 18 2 Fluorides 18 1 Without problem 13 5 Fecal Coliforms means a problem (disinfection) Other parameters mean only aesthetc problems, but fluorides

40 Phase III Identifying PICKS in chromatogrames

41 Study of selected compounds in wastewater and groundwater l ( µg/l) Importance of soil treatment capabilities, specifically for organic compound removal Compound Wastewatwe Site 1 Site 2 Site 3 Methyl (1-methyethyl) < 5 < 5 < 5 benzene 1,1-oxy-bis-benzene <5 < 5 < 5 4-nonyl phenol 1,2,4 trichlorobenzene < < < 5 Benzenes 100 <5 < 5 < 5 Phenols PAH 25 <5 < 5 < 5

42 PHASE IV Treatment processes for the Mezquital Valley groundwater Well water Activated Carbon Filtration Membranes (NF, RO) Treated effluent UV Disinfection Chlorine Treatment Processes for the secondary effluent WWTP Secondary effluent Sand Filtration Ozonation Activated Carbon filtration (1) Treated effluent UV Disinfection Chorine Membranes (NF+RO) Activated Carbon filtration (2)

43 Application of membrane processes Raw Wastewater Cerro Colorado Spring Well 115 Nanofiltration effluent Chromatograms of the raw wastewater, infiltrated water (Tezontepec and Cerro Colorado) and the nanofiltration effluent

44 Springs water treatment results Filtration with Reverse Osmose or Nanofiltration Chromatogram picks disappear, TDS less than 70 mg/l, and ph acid Too Too clean Studies Studies still undergoing

45 PHASE V To identify and evaluate the flora and animal life present in the Cerro Colorado Spring and for to estimate some impact for the presence to toxics compounds

46 Cerro Colorado Spring Origin It appeared 35 years ago as a natural exit of the Mezquital Valley aquifer due to the overload with raw wastewater

47 Diverse aquatic populations usually presented in non polluted systems SITE 1 SITE 2 SITE 3 SITE 4 SITE NUMBER Anelides Hyalellas Snails latyhelminthes Fresh water shrimp Macrocyclops Stentor Ostracoda Asellus

48 Percentage of females and males in fishes Family Genus Poecilidae Heterandria Family Goodeidae Species H. jonesi Genus Allotoca Species A. regal is % of fis Male Female

49 ARTHROPODS, known as Mexican acocil, indicators of very clean water

50 Supply altenatives for Valley of Mexico (2240 masl) SOURCE Capacity m 3 /s Head m Distance km Cost ($/m 3 ) Temascaltepec Amacuzac Tecolutla Mezquital Valley

51 Further work Epidemiological and Toxicological studies Disinfection byproducts study for the Mezquital area Research on contaminant removal mechanisms and fate of contaminants in the natural system (on going) Industrial Pretreatment programs Evaluation of membrane treatment processes at pilot scale (on going) Education and communication programs Development of an appropriate regulation