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International Success Stories in Wastewater Treatment and Reuse. MEDAWARE. Outline. Introduction: Benefits and Domains of Wastewater Reuse Success Stories in Mediterranean Region: Spain: Vitoria and Tenerife Plants Greece: Chalkis Island Plant Italy: Catania Projects
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International Success Stories in Wastewater Treatment and Reuse MEDAWARE
Outline • Introduction: Benefits and Domains of Wastewater Reuse • Success Stories in Mediterranean Region: • Spain: Vitoria and Tenerife Plants • Greece: Chalkis Island Plant • Italy: Catania Projects • Palestine: Dan Region Project • Cyprus: Larnaca Plant • Other Examples • Success Stories all over the World: • Australia: Bolivar Project • USA: Monterey, California
Introduction • Best Practices and Success Stories in Wastewater Treatment Systems are: • Systems employing an effective treatment technology leading to a good quality effluent • Systems with high contribution into the overall increase of wastewater reuse in the relevant country • Systems achieving sustainable wastewater treatment and reuse practices
Benefits of Wastewater Reuse • Potential benefits of wastewater reuse are most obvious for the arid areas but the general increasing pressures on water resources all over the world is also making wastewater reuse attractive in other areas. All these benefits contribute to the ultimate objective of sustainable use of water resources
The Mediterranean Region: The Need for Wastewater Reuse • It is characterised by the low level and irregularity of water resources, through time (summer drought, interannual droughts) and space (dry in the South). • It includes 60% of the world population with renewable natural resources of less than 1,000 m3 of water/inhabitant/year. • The strong growth in urbanisation, tourism, irrigation and population can only increase tensions on water demand.
Objectives of the Reuse Scheme • A Tertiary Treatment Station was added in 1995 to the Municipal Wastewater Treatment Plant to obtain a better effluent capable of: • Increasing water supply to Vitoria and Bilbao cities • Replacing ecological flows to the Zadorra dams when they are deficient • Irrigating 10,000 ha of agricultural land • Protecting the trout fish of the Zadorra River
The Treatment Technology Secondary treatment (screening, sedimentation, nitrification-denitrification) + tertiary treatment (coagulation-flocculation, sand filters, chlorine disinfection)
Settling Ponds Flocculation Chambers Sand Filter Filling up Sand Filter Washing Filtered Water
Mixing Pumps Chlorination Chamber
Effluent Reuse • The Plant will generate 20,000,000 m3/year of treated effluent: • 8,000,000 m3/year will be used for irrigation without cultivations restriction • 12,000,000 m3/year will be added to the Zadorra River ecological flow • The effluent is suitable for drinking water supply!! (illegal at present) • Cost: 0.06 €/m3
Treated Effluent Treated Effluent Irrigation Irrigation
Plant General Characteristics • Constructed between 1995 and 1997 to alleviate the water shortage of the island of Tenerife • Designed for a flow of 90,000 m3/d • Effluent is used to irrigate a crop area located 70 km away from the Plant Plant Reservoir
The Wastewater Reuse System 61 km; 0.6 km diameter Gravity Pipe completely filled 50,000 m³; 10 m deep 15.000 m3 6.7 km 457,000 m³; 20 m deep 250,000 m³; 15 m deep Activated Sludge
Aeration Tanks Screening Grit Removal Activated Sludge Tanks
San Isidro Reservoir Gravity Pipe El Saltadero Reservoir San Lorenzo Reservoir
Problem and Solution • Anaerobic conditions build-up in the long pipe that transports the effluent leading to sulphide generation • Fresh water over-saturated with DO started to be injected at 10 km from the pipe inlet nitrification-denitrification process anoxic conditions inhibition of sulphide generation reduction in NH3-N less chlorine requirement for disinfection
Effluent Reuse • Reuse of 7,000,000 m3/year of treated effluent • Irrigation of 775 ha of banana mainly, plus potatoes and tomatoes • Acceptable quality, and studies are ongoing for its improvement using micro and ultra filtration • Cost: 0.45 €/m3
Plant General Characteristics • Constructed in 1994 • Reclamation of wastewater started in 1998 • Daily flow of 9,000 m3/day
Disinfection Process • In 1998, ultraviolet disinfection using two types of UV systems (closed and open type) and chlorination was introduced • The first UV bank produced 55 mWs/cm2. After test, it was decided to increase the total dose of the UV lamps to 120 mWs/cm2
Effluent Reuse 1994 2000 • Reuse of 4000 m3/day of treated effluent for landscape irrigation (280 ha with 100,000 trees and bushes) and industrial use
Grammichelle Developed in 2001 Flow: 1,500 m3/d Activated Sludge + Chlorine Contact Tank + Tank Storage Quality: BOD5 < 10 mg/l; COD < 30 mg/l Reused for irrigating orange, olive trees, crops for caning industry, and vegetables to be eaten cooked Cost: 0.11 €/m3 Caltagirone Developed in 2001 Flow: 5,200 m3/d Activated Sludge + Sand Filtration + Reservoir Storage Quality: BOD5 < 10 mg/l; COD < 30 mg/l Reused for irrigating orange, olive trees, crops for caning industry, and vegetables to be eaten cooked Cost: 0.11 €/m3 Projects Characteristics
Plant and Effluent Characteristics • Constructed in 1991-1994 • Flow of 120,000,000 m3/yr
Effluent of biological treatment including nutrient removal is spread on sand basins and thus recharged into the groundwater aquifer for additional polishing and long-term storage Treatment Technology
Effluent Reuse • In 1993, 75 out of 87 Mm3 of treated wastewater was recharged and about 100 Mm3 (together with groundwater) was used for agricultural irrigation in Negev of an area of ~ 16,000 ha of field-crops (cotton, cereals, sunflower, etc.), fruit plantations, vegetables, and flowers aimed for export • Cost: 0,45 US$/m3
Plant General Characteristics • Located behind the International Airport of Cyprus • Operation started in 1995, and reuse for irrigation purposes in 2000 • Design capacity: 8,500 m3/d; In summer: 5,500 m3/d and in winter: 4,500 m3/d
Sand Filtration Unit Irrigation Pumping Station Filter Press Sludge Drying Beds
Effluent Reuse • Irrigation of 150 ha of corn and alfalfa at Dromolaxia Village; these started to grow noticeably fast • Irrigation, during the summer season, of gardens, parks and fields owned by hotels, the International Airport and Larnaca Municipality • Cost: 0.5 €/m3