Managing aquifer recharge a sustainable way for drinking ... · Managing Aquifer Recharge Prof. Dr....

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Managing aquifer recharge – a sustainable way for drinking water supply

Prof. Dr. U. Tröger

TU Berlin

Dean of Water Engineering Campus El Gouna - Egypt

Chair of Hydrogeology - Berlin

Rainwater harvesting (Gaza strip) a failed EU project

Prof. Dr. Tröger Regional Swim Conference Managing aquifer recharge Sharm El Sheikh

Flooding during long extended rainfall

32 million cubicmeter are lost in a small catchment during March 8th 2014 in El Gouna – Red Sea

Infiltration wells

Collection-, sedimentationtank and recharge wells

Flood controll

A combination of surface and subsurface dams

small and big obstacles

clay traps

Why rainwater harvesting?

• Rainwater has a good quality

• Rainwater is low mineralized

• Infiltrated or injected rainwater can dilute the reused higher mineralized treated sewage

Managing Aquifer Recharge

• MAR has to follow a target (economy!)

• MAR can be executed for different purposes

1. To have groundwater available during dry periods

2. To store water during wet years for years with less precipitation

3. To manage quality (dilution and sea water intrusion)

4. To manage sea water intrusion

5. Intelligent reuse of treated sewage

Recharge and pumping (recovery) MAR

Aquifer storage and recovery (ASR)

ASR involves injection of water into a well for storage, and recovery from the same well. The aquifer may be confined or unconfined. Examples are found mainly in Australia as in Salisbury, and the suburbs of Adelaide (treated sewage).

Aquifer storage, transport, and recovery (ASTR)

ASTR involves injection of water into a well for storage, and recovery from a different well, generaly to provide addional water treatment. An exaple is at the Erftverband, North Rhine Westfalia, West Germany.

Artificial recharge and recovery

Zoning around the recharge area

Pollution risk

Primary, secondary, tertiary treated

First field tests

• Treated sewage is tested on an artificial trench

• Horizontal drains enable the option of sampling the percolating water in different depth

Sewage water quality

Pollution of groundwater with sewage

The range of potential groundwater pollutants in wastewater includes pathogenic microorganisms, excess of nutrients and dissolved organic carbons, an where significant industrial effluent is present , toxic heavy metals and organic compounds.

• the pollution vulnerability of the aquifer

• the pollution of natural groundwater and thus its potential use

• the origin of sewage effluent and thus likelihood of persistent contaminants

• the quality of wastewater, and its level of treament and dilution

• the scale of wastewater infiltrion compared to that of the aquifer throughflow

• the mode of wastewater handling and land application.

Irrigation

Surface Systems

Surface systems have an efficiency rate of 45 to 60 percent, although well-planned surface methods may perform at a 70 to 85 percent efficiency rate, according to the Washington State University Extension.

Subirrigation Subirrigation systems, also known as zero-runoff systems, water the root zone from below and are commonly used in container planting. Instead of seeping into the soil and down into the root zone, the water is absorbed upwards from beneath the plant root zone.

Organic compounds in sewage effluent

Underground infiltration

Infiltration methods

Trench infiltration

Infiltration in trenches

The drainage hose is used for a better distribution of infiltration

Dug well infiltration

Treated sewage water used for MAR in Australia

Artificial groundwater recharge to control salinity

High chloride content can be be diluted with artificial recharge.

Even treated sewage may be used if the mineralization is very high

Cl- g/ L

MAR for controlling contaminant flow

Defense of seawater intrusion

• Treated sewage is injected in a well far enough to be free of bacteria when reaching the fresh water well.

• The gradient in direction to the sea defense the sea water intrusion

Seawater

Treated sewage Q

Cultivated area partly with sewage

• From 1923 (Gabal el Aswar) and 1932 (Abu Rawash) flood irrigation was used

• Abu Rawash this was changed to furrow irrigation

Construction of sewage farms

Treatment plant, constructed wetland, and waste deposit

Jet irrigation in Braunschweig

Braunschweig treated effluent

Problems

Treated water in – drinkinking water out?

Clogging effects

Change in chemistry due to:

ion exchange

adsorbtion and advection

new minerals

clay expansion

Thank you for your attention

Managing aquifer recharge a sustainable way for drinking ... · Managing Aquifer Recharge Prof. Dr....

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