water quality and reuse in agriculture and urban...

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DAMIA BARCELO DAMIA BARCELO 1,2 1,2 1 ICRA - Catalan Institute for Water Research, Girona, Spain 2 IDAEA-CSIC, Department of Environmental Chemistry, Barcelona, Spain Water Quality and Reuse in Agriculture and Urban environment. Case study from Barcelona (Spain)

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DAMIA BARCELODAMIA BARCELO1,21,2

1ICRA - Catalan Institute for Water Research, Girona, Spain 2IDAEA-CSIC, Department of Environmental Chemistry, Barcelona, Spain

Water Quality and Reuse in Agriculture and Urban environment. Case study from Barcelona (Spain)

Global Earth Observation System of Systems (GEOSS)

InternationalHydrologicalProgramme (IHP)

•The water cycle is changing?•Increased risks?•Growing vulnerability?•More disasters ?•Less water for people?•Crisis is looming?•What crisis?•Global or local?

• Water CyclingDeeply Embedded in Earth System

• Interconnections are Strong

• Change to One Part Reverberates Throughout

The Global Water System

Impact of climate change

• Increased frequency of water shortages and decline in water quality, increasing frequency/intensity of droughts (Reductions in water availability would hit southern Mediterranean countries the hardest)e.g., year 2030, Guadiana river basin 1ºC, 5% less rainfall, 11% less water availability

• Increase in extent and severity of desertification

• Increase in erosion, salinisation and fire hazard and reductions in soil quality

• Loss of valuable ecosystems, loss of natural habitats and biodiversity

• Falls in production and world price rises resulting in threatened food security, reduced crop production, reduced water availability for irrigation

Introduction – the Mediterranean • The Mediterranean Sea is the largest semi-enclosed European sea, characterized by a

narrow shelf, a narrow littoral zone and a small drainage basin especially in the northern part.

• 82 million people live in coastal cities (by 2025 there will be an estimated 150-170 million)

• 32 % of the region's population lives in the southern countries (by 2025 that is expected to have reached 60 %).

• Expected increase in environmental pressure in the immediate future (the rise in population will be mainly concentrated in the countries in the southern and eastern Mediterranean)

• Human activity in coastal areas is leading to serious pollution problems, caused by the large quantities of industrial and urban waste that are produced, in a sea with a low capacity for self-decontamination and a slow water renewal cycle

• Seasonal population pressures are also very high (tourism)

Global Change in the Mediterranean Area

a) CLIMATE CHANGE

Temperature Precipitation+ –

Predicted relative changes in Temperature and Runoff at global scale (A1B scenario).[Source: IPCC Synthesis report, 2007]

Predicted relative changes in Temperature and Precipitation in the Mediterranean Area (A1B scenario).[Source: Christensen et al., 2007]

Access to safe drinking water and sanitation(source: UN-SDMI,OMS-Unicef, 2003)

It is estimated that 30 million Mediterranean people live without access to clean drinking water

Water scarcity

• The regions included in the Mediterranean basin are amongst the world areas most suffering of water scarcity

• Irregular water supply and rising water demands.

• Water scarcity has a direct impact on citizens and economic sectors that use and depend on water, such as agriculture, tourism, industry, energy and transport.

• Example: 2007-2008 drought in NE Spain, with an extremely high societal, economical and environmental cost.

Potential alternatives and needs with respect to existing water resources

• Culture of water-saving and valuing ecosystem services

• Improvement of wastewater treatment quantitatively and qualitatively

• Reuse of treated effluents and sludge• Treatment of drinking water - Desalination • Protection of aquifers

3. Reuse of treated effluents

• Reuse of sewage waters can be considered as an adequate water source for urban, tourism and agricultural uses.

• With proper treatment, sewage water can even be used for drinking water.

• There exist several techniques adequate for the improvement of chemical and microbiological quality that could help to provide these uses.

• The solutions are linked, however, to available energy; this sometimes becomes the critical limitation.

• Public perception and cultural issues also needs to be evaluatedand improved when this source of water is considered. Thus public consultation would help to early detect future misunderstandings

• In Catalonia, up to 101 Mm3 (2027) for water reuse (average energy costs 3.8 kWh/m3)

Potential alernatives and needs with respect to existing water resources

Catalonia is suffering what has been qualified as

“Structural Water Shortage”

Estimated Water Deficit in the Catalan Internal Basins (projection 2025):

300 Hm3/year (+955 Hm3/ /year )

NEW WATER RESOURCES ARE NEEDED!

389TOTAL INCREASE (by 2025)

55Improvement of water treatment, regulation

and systems

INFRASTRUCTURE IMPROVEMENT

43Groundwater

Recharge & Recovery

101 (51)Reuse

190 (80)DesalinationNEW RESOURCES

Hm3/year

Source: Catalan Water Agency (ACA), 2009

Planned Management Measures (2025) :

Treated wastewater reuse for agricultural and landscape irrigation

Advantages include:• Source of additional irrigation water.• Savings of high quality water for other beneficial uses.• Low-cost source of water supply.• Economical way to dispose of wastewater and prevent pollution and sanitary problems.• Reliable, constant water source.• Effective use of plant nutrients contained in the wastewater, such as nitrogen and

phosphorus.• Provides additional treatment of the wastewater before being recharged to groundwater.Disadvantages include:• Wastewater not properly treated can create potential public health problems.• Potential chemical contamination of the groundwater.• Some of the soluble constituents in the wastewater could be present at concentrations toxics

to plants.• The treated wastewater could contain suspended solids at levels that may plug nozzles in

the irrigation distribution system as well as clog the capillary pores in the soil.• The treated wastewater supply is continuous throughout the year while the demand for

irrigation water is seasonal.• Major investment in land and equipment.• Final key question: who will pay the bill ?

Treated wastewater reuse for agricultural and landscape irrigation

Key issues:

• Boron• Salinity • Exchangeable cations • Trace Metals• Organic contaminants (Important issue: EMERGING CONTAMINANTS)• Pathogens

Treated wastewater reuse for groundwater recharge

The purposes of groundwater recharge using treated wastewater: • To establish saltwater intrusion barriers in coastal aquifers. • To provide further treatment for future reuse. • To augment potable or non potable aquifers. • To provide storage of treated water, or to control or prevent ground

subsidence.

There are four major water quality factors to be considered in groundwater recharge with treated wastewater:

• Pathogens• Total minerals • Heavy metals• Organic contaminants

Treated wastewater for direct and indirect potable reuse

Perhaps you have seen: “ This property is irrigated with reclaimed water. Do not drink”

Requires Advanced Environmental Technologies (like the one in Advanced Water Purification Facility, California)

Micro-filtration Reverse Osmosis Membranes Hydrogen peroxide and UV light, Aquifer recharge by Injection to wells (travels up to six month to drinking water well)

“ As waters supplies tighten, perhaps more communities will be asked to put their faith in chemistry and accept recycled water into drinking water supply”

Treated wastewater for direct and indirect potable reuse

Potential constraints

• Potentially toxic chemicals• Public health• Public acceptance

Case study : El Prat (Barcelona) WWTP

Objective: To investigate the impact of discharges of tertiary treated sewage on the load of polar emerging pollutants in a typical Mediterranean River (Llobregat) during a drought period (2007-2008).

Tertiary effluent

2008:• 266,500 m3/day of wastewater (97.5 hm3/y) [Design: 420,000 m3/day]• 1,141,538 eq. inhabitants

WWTP + WRS (Water Reclamation Station):(El Prat, Barcelona, Spain)

Secondary biological treatmentwith N & P reduction

Primary treatment

• Basic treatment• Max flow = 320.000 m3/day• Filtration and disinfection steps

• Advanced treatment (Reverse Osmosis)• Flow = 2.500 m3/day (can be15.000 m3/day)

Tertiary treatmentto reuse 33.2 hm3/y

Secondary treatment68.9 hm3/y, of the effluents discharged into the Mediterranean Sea through an emissary 3.2 km long.

67.5 %,

32.5

%,

Tertiary treatment in WRS (El Prat)

Physico-chemical Microfiltration 10 microns UV disinfection + Chlorine

Basic treatment

Ultrafiltration Reverse OsmosisSecodary effluent

Basic treatment

Advanced treatment with osmosis

AGRICULTURAL IRRIGATION

INDUSTRIAL HYDRAULIC BARRIER AGAINST SALINE INTRUSIONGREEN AREAS

Expected Regenerated Water Demands (~ 50 hm3/year)

FLOW MAINTENANCE IN THE LLOBREGAT RIVERRECHARGE PONDS FOR THE AQUIFER IN THE LLOBREGAT DELTA

WETLANDS IRRIGATION IN THE LLOBREGAT DELTA

Water reuse in theLlobregat river:

Sampling at lower section of the Llobregat River (NE Spain), in the surroundings of the town of Barcelona during the fall of 2008, as a consequence of the severe

drought that took place during 2007-2008 in the area.

Sampling Points

a) Point 1: river upstream

b) Point 2: intake of an important drinking water treatment plant supplying water to Barcelona

c) Point 3: treated water from the WWTP tertiary treatment of El Prat de Llobregat

# 1

# 2# 315.6 Km

Loads (mass-flows ) balances (2) River vs. Effluent relative contributions

Load river downstream(#2) = Load river upstream(#1) + Load effl. discharged(#3)Load (point i, compound j) = Qj · cij

• All compound classes detected at similar concentrations in tertiary effluents and river water, except for estrogens being detectable only in sewage effluent at very low levels

• In general, detected concentrations are similar to or slightly below those reported previously in the Llobregat River and in other Spanish Mediterranean rivers

WWTP tertiary effluent Point 3 Surface water point 1

Pharmaceuticals

Estrogens

Pesticides Illicit drugs

Alkyl phenols

Upon aggregation of the loads at family level:

• Both river upstream and effluent discharged contribute to pharmaceuticals, drugs and pesticides

• Estrogens originate from the WWTPtertiary effluent

• In contrast, the presence of alkyl phenols derivatives (Figure 3e) can be associated to the upstream river (ca. 80%).

Recommendations/Conclusions of the Water Directors/Scientists

• There is an understanding that climate change is happenning in the Mediterranean basins. Adaptation to climate change has started but progresses rather slowly.

• Barriers for adaptation to climate change are:spatial and temporal uncertainities, lack of adequate fianancial resources and lack of horizontal cooperation

• Efforts should be pursued so as to downscale crucial climate related data/information at the lowest possible level throughout the region.

• With respect to the climate�water�energy nexus, the rising cost of conven-tional energy sources (in particular oil) should be considered when developing new water resources (eg. desalination and transfers). -Due consideration should be given to impacts on the environment. �

• The level/degree of water quality needed for the various usages (agriculture, drinking water, ecosystems) has to be assessed in the light of the different water treatment technologies available and their respective cost.

• encourage the necessary diversification of economic activities towards activi-tiesless impacted by climate change, keeping in mind the need for equity considerations in tackling climate change.

Conclusions • Reuse of treated sewage waters can be considered as an adequate

water source for urban, tourism and agricultural uses.

• With proper treatment, sewage water can even be used for drinking water.

• Major environmental pollution such as dissolved oxygen depletion, eutrophication, foaming, and fish kills can be avoided by, for instance, planning the reuse of treated wastewater.

•• Advantages of wastewater reuse are :

– Reduction of fertilizers– The organic matter added through wastewater irrigation serves as a soil

conditioner over time, increasing its water holing capacity. – Increased protection of the aquifers. (the increasing use of wastewater for

irrigation help to decrease the degree of groundwater exploitation thus avoiding seawater intrusion in the coastal areas).