Evaluating Impacts of Recharging ... - environment.gov.psWeighting" (IDW), which is the most common...

Evaluating Impacts of Recharging Partially Treated Wastewater on Groundwater Aquifer in Semi-Arid Region by Integration of

Monitoring Program and GIS Technique

Case Study: North Gaza Infiltration Basin

سلطة جودة البيئة

الطبيعيةللمصادر الإدارة العامة

تـــــامـــر الـصــلــيـبـي . د

1تقديم

أحواض الترشيح

أحواض شمال غزة: حالة الدراسة•

مكبات النفايات

مكب غزة: حالة الدراسة•

محطات التحلية

ات غزةمحافظ: حالة الدراسة•

علىلبيئةاجودةسلطةتعكفوحمايتها،الفلسطينيةالبيئةعلىالحفاظفيالبيئةجودةسلطةدورمنانطلاقا

:وتشملالجوفية،المياهجودةعلىبيئيا الساخنةالمناطقأثرومراقبةدراسة

Conclusion & Recommendations

Methodology

Objective

Introduction

المحتويات

Results and Discussion

2

About VONTRON - Company Profile Introduction

• The overall annual water use in theGaza Strip is ~180 Mm3, where theoverall annual supply is only ~120Mm3 leading to an annual deficit ofabout 60 Mm3 (Al-Dadah, 2013)

• This deficit has resulted in a continuousdeclination of the of groundwater levelaccompanied by groundwater qualitydeterioration.

• The policy by the PalestinianWater Authority (PWA) adheresthe use of nonconventional waterresources such as wastewaterreuse for irrigation and artificialrecharge of groundwater PWA,2011 & Al-Juaidi et al., 2014)

• The current generated quantities of thewastewater is estimated at 36.5 Mm3

every year (CMWU, 2013; Abunada andNassar, 2014; UNSCO, 2012) that areproduced by the municipal seweragesystems, a figure which could rise to 57Mm3 annually by 2020 (UNSCO, 2012).

Most of these quantities have been disposed either to the sea or flooded to the surroundingareas after being partially treated. Consequently, a severe damage to the environment andthe ecosystem is taking place.

3

Objective4

The current study investigates the impacts ofrecharging partially treated wastewater from theeffluent of Beit Lahia wastewater treatment plant(BLWWTP) on groundwater quality.

Project Idea 5

Terminal Pumping Station

Pressure Line (7 Km)

9 Infiltration Basins (8.1

hectares)

Started operation in 4/2009

Project Idea 5

Risk Management: Effluent Recovery and Reuse Scheme includes:

To mitigate the expected impact of the infiltrated wastewater on the aquifer a Recovery and

Reuse Scheme is intended to be implemented.

The concept of the Recovery Scheme is to capture pollution plume via 27 pumping wells by

extracting 110% of the infiltrated quantities).

The Recovery Scheme is surrounding the Basins from the North, South and the West

(according to the expected flow of the stream).

Study Area5

The North Gaza Emergency Sewage Treatment (NGEST)Project was initiated in 2009 at Beit Lahia city, 9 km tothe North of Gaza city with the help of Multi donortrust fund lead by the World Bank.

Study Area5

The current infiltration basin is thelargest wastewater infiltration basin inthe Gaza Strip and was constructedaccording to the engineering standards.

Its design capacity is about 35,600 m3/dand it can be upgraded up to 45,000m3/d according as per the future plans.

Currently, about 20,000 m3 of treatedeffluent from the BLWWTP is diverteddaily to nine spread infiltration basinswith a total base area of 32.4 hectares(ha)

Distributed to nine ponds with anaverage area of 3.6 ha/pond as shown inFigure 1.

Methodology6

2. Simulation Program UsingGIS for years 2011, 2012, 2013,2014

Groundwater Quality Monitoring Program

Groundwater Sampling from13 wells

3. Data Analysis

Conclusion & Recommendation

Wastewater Sampling

1. Sampling Program

Statistical Analysis

Methodology Cont.…7

Monitoring Program

1. Wells Location

The groundwater andwastewater samples werecollected from the 13 selectedwater wells (7 watermonitoring and 6 agriculturalwells).

The wells located to the west ofthe infiltration basin arerepresenting the downstreamside

the water wells are formingtwo circles around theinfiltration basin at a distanceof 300 - 600 m from the basin.

8

The investigations were carried out by collecting groundwater samples from the entireboreholes around the infiltration basins in addition to samples from the rechargedwastewater through a long term monitoring program between years 2011-2014.

(oC)

(pH)

(EC)

(TDS)

(NO3)

(Cl)

(NH4)

(Br)

Chemical Parameters

Methodology Cont.…

2. Testing Parameters /Indicators

3. Testing Periods

Chemical indicators

Physical indicators

8

Experimental data was tested for the analysis of variance (ANOVA) before testing theeffects of infiltration of partially treated wastewater on groundwater qualityparameters.

The F-test was used to describe this effect.

A probability level, p of 0.05, was used for all statistical comparisons.


4. Statistical Data Analysis

9

The Geographic Information System (GIS) was usedto visualize the spatial distribution of the impact ofwastewater infiltration within an area of about600m radii around the North Gaza infiltration basinin the periods 2011, 2012, 2013 and 2014.

The current study used the "Inverse DistanceWeighting" (IDW), which is the most commonmethod used to interpolate unknown points(Alslaibi et al., 2011).

IDW is an interpolation method that estimates thecell values by averaging the values of a sample datapoints in the neighbourhood of each processingcell. The closer the point to the centre of the cellbeing estimated, the more influence, or weight ithas in the averaging process (ArcGIS Desktop,2010).


5. Geographic information System (GIS) technique

10

1. Infiltrated wastewater characteristics

Results & Discussion

It can be noticed that there is no considerable change in the wastewater parameters mainly pH,TDS and chloride concentrations.

However, an increase in BOD, COD, ammonium and TSS level was noticed with time through theyears 2008, 2011, 2012 and 2013.

This quality deterioration might be due to the increase volume of generated wastewater with lowtreatment capacity of the BLWWTP.

The effluent of the NGWWTP: Fit to Aquifer Recharge and Unrestricted Reuse

BOD5 10-20 mg/L TSS 15-20 mg/L

ParameterConcentration

Mar. 2008 Mar. 2011 Feb. 2012 Jul. 2013 Apr. 2014

PH 8.1 7.38 7.29 N.A N.A

Electric Conductivity(EC) (μ.s/cm) 1248 2850 2486 N.A N.A

TDS (mg/L) 1532 1698 1541 N.A N.A

TSS (mg/L) 95 80 58.5 250 138

DO (mg/L) N.A 6.3 6.1 N.A N.A

Nitrate (NO3) (mg/L) 50.4 26 49 1.1 0.8

Chloride (Cl) (mg/L) 289 304 304 N.A N.A

Ammonia (NH4) (mg/L) 4.07 4.5 4.5 88 99

COD (mg/L) 266 205 195 450 372

BOD5 (mg/L) 109.3 95 72.5 240 190

BOD5/COD (%) 0.5 0.46 0.37 0.53 0.51

Boron (mg/L) 0.308 0.352 N.A N.A N.A

0

100

200

300

400

500

2008 2011 2012 2013 2014

Co

nce

ntr

ati

on

(m

g/l

)

Ammonia (NH4) COD

BOD5 TSS

23 Results & Discussion …cont.

A noticeable increase in the groundwater especially in 2013 which confirms that therecharging was taking place. However, this increase was fluctuating due to the continuousabstraction through the irrigation wells in the vicinity of the area

The increase in the groundwater level is expected to continue growing once the infiltratedamount grows up to the maximum capacity of the infiltration basin (35000 m3/day).

This suggests a replenishment of the groundwater aquifer may take place once therecharging amount increases which may confirm the potential of using recharged wastewaterin improving the groundwater level (Asanoa.T, & Cotruvob .J.A, 2004)

1. Groundwater level

-10

-8

-6

-4

-2

0

2

4

6

8

DB4 SW MW1 MW2 MW3 MW4 MW5 Q15 Q64 Q20 Q86 Q56

Dep

th m

Well Name

2011 2012 2013 2014

24 Results & Discussion …cont

❷

Infiltration Rate vs. Pumped Quantities

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

2.20

2.40

0

50000

100000

150000

200000

250000

300000

350000

400000

450000

500000

550000

600000

Jan-11 Jul-11 Feb-12 Aug-12 Mar-13 Oct-13 Apr-14 Nov-14 May-15 Dec-15

M/D

AY

M3

/MO

NT

H

Pumping (m3/month)

Average for all basins

Infiltration Rate (same month comparison)

0.00

1.00

2.00

3.00

4.00

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

INFI

LTR

ATI

ON

RA

TE (

M)

MONTHS

2012 2013 2014 2015

Infiltration rate vs quality of wastewater

0

0.5

1

1.5

2

2.5

0

100

200

300

400

500

600

Jan-11 Jul-11 Feb-12 Aug-12 Mar-13 Oct-13 Apr-14 Nov-14 May-15 Dec-15

M/D

AY

MG

/L

COD, mg O2/L BOD5, mg O2/L

TSS TkN

Average for all basins

Pumped quantities per month

0

100,000

200,000

300,000

400,000

500,000

600,000

Jan

-11

Feb

-11

Mar

-11

Ap

r-1

1M

ay-1

1Ju

n-1

1Ju

l-11

Au

g-11

Sep

-11

Oct

-11

No

v-11

De

c-1

1Ja

n-1

2Fe

b-1

2M

ar-1

2A

pr-

12

May

-12

Jun

-12

Jul-

12A

ug-

12Se

p-1

2O

ct-1

2N

ov-

12D

ec-

12

Jan

-13

Feb

-13

Mar

-13

Ap

r-1

3M

ay-1

3Ju

n-1

3Ju

l-13

Au

g-13

Sep

-13

Oct

-13

No

v-13

De

c-1

3Ja

n-1

4Fe

b-1

4M

ar-1

4A

pr-

14

May

-14

Jun

-14

Jul-

14A

ug-

14Se

p-1

4O

ct-1

4N

ov-

14D

ec-

14

Jan

-15

Feb

-15

Mar

-15

Ap

r-1

5M

ay-1

5Ju

n-1

5Ju

l-15

Au

g-15

Sep

-15

Oct

-15

No

v-15

De

c-1

5

Total Infiltrated Quantities (m3) per month

Cumulative Pumped quantities (MCM)

0123456789

101112131415161718192021222324252627

Ap

r-0

9M

ay-0

9Ju

n-0

9Ju

l-09

Au

g-09

Sep

-09

Oct

-09

No

v-09

Dec

-09

Jan

-10

Feb

-10

Mar

-10

Ap

r-1

0M

ay-1

0Ju

n-1

0Ju

l-10

Au

g-10

Sep

-10

Oct

-10

No

v-10

Dec

-10

Jan

-11

Feb

-11

Mar

-11

Ap

r-1

1M

ay-1

1Ju

n-1

1Ju

l-11

Au

g-11

Sep

-11

Oct

-11

No

v-11

Dec

-11

Jan

-12

Feb

-12

Mar

-12

Ap

r-1

2M

ay-1

2Ju

n-1

2Ju

l-12

Au

g-12

Sep

-12

Oct

-12

No

v-12

Dec

-12

Jan

-13

Feb

-13

Mar

-13

Ap

r-1

3M

ay-1

3Ju

n-1

3Ju

l-13

Au

g-13

Sep

-13

Oct

-13

No

v-13

Dec

-13

Jan

-14

Feb

-14

Mar

-14

Ap

r-1

4M

ay-1

4Ju

n-1

4Ju

l-14

Au

g-14

Sep

-14

Oct

-14

No

v-14

Dec

-14

Jan

-15

Feb

-15

Mar

-15

Ap

r-1

5M

ay-1

5Ju

n-1

5Ju

l-1

5A

ug-

15Se

p-1

5O

ct-1

5N

ov-

15D

ec-1

5

CU

MU

LATI

VE

INFI

LTR

ATE

D Q

UA

NT

ITIE

S (M

CM

)

The TDS concentrations in the study area ranges between 965 and 1948 mg/l dependingof the aquifer layer from which the water is pumped.

The monitoring data of the TDS level showed insignificant increase in TDS over themonitoring period.

0

250

500

750

1000

1250

1500

1750

2000

2250

DB4 SW MW1 MW2 MW3 MW4 MW5 Q15 Q64 Q20 Q86 Q56 Q53 IWW

mg/L

Well Name

2008 2011 2012 2013 2014


1. TDS

This may be due to the close level of the TDS concentration in the BLWWTP effluentcompared with native groundwater.

The influent to the BLWWTP is collected from within the Gaza northern area where theTDS level in the water network is in the range of ~1000 mg/l.

Consequently, the sewage has naturally almost the same level of TDS. The chemicalanalyses for samples from the BLWWTP effluent showed that the TDS level is in the samerange (1500 to 1700 mg/l).

However, the TDS concentrations in wells Q64, Q20 fluctuated due to pumping rate andup coning phenomena.


The monitoring data form the surrounding boreholes showed significant reduction in thechloride ion concentration over the monitoring period (p<0.05).

Most of the surrounding wells anticipated a drop in chloride concentration mainly for years2013 and 2014 compared with the base line year 2008.

This improvement was expected as the level of chloride in the BLWWTP effluent was even lessthan that in the native groundwater suggesting that the wastewater infiltration caused somechloride dilution.

This improvement in chloride level can also be attributed due to the sandy soil layers wherethe wastewater passing through before it reaches the groundwater aquifer.

2. Chloride (Cl)

0

100

200

300

400

500

600

700

800


mg/L

Well Name

2008 2011 2012 2013 2014

It is worth mentioning that the chloride level in the agricultural wells (Q64 and Q20) wasrelatively high compared with other water wells which might be due to the over use and thehigh pumping rate from these two wells (70 m3/h).

This was supported by the relatively high concentration of the EC (2900 μ.s/cm) for those twowells compared with others.

This ensues that the chloride concentration in the groundwater is highly affected by theoriginal level experienced at the BLWWTP effluent and the wastewater infiltration hasimproved its quality.


This results agrees with the onereported by (Icekson-Tal andBlanc, 1998) where they foundthat the SAT system reducedthe level of the chloride in theeffluent in the Dan Region from289 mg/l where it was droppeddown to 266 mg/l due to theSAT effect.


A significant drop in nitrate concentrations was also noticed in all monitoring wells comparedwith the base line 2008 year (P<0.05).

The closer the water well to the infiltration basin, the higher the drop in the nitrateconcentration is (i.e. the drop was obvious in water wells SW, DB4, MW3, MW5 and Q53).

This reduction in nitrate level may be due to the partially treatment taking place at the BLWWTP.

On the other hand, less reduction in nitrate level was noticed in water wells which are furtheraway from the infiltration basins (i.e. wells Q15, Q64 and Q20) at a distance of about 600 mfrom the infiltration basins.

3. Nitrate (NO3)

0

20

40

60

80

100

120

140

160

180

200


mg/L

Well Name

2008 2011 2012 2013 2014


Similar results were alsoreported for the Dan Regioncase (Details about DanRegion) where the totalnitrogen in the appliedeffluent decreased by morethan 70% through the SATprocesses showing asignificant nitrogen removal(Icekson-Tal and Blanc, 1998)


Unlike the chloride and the nitrate levels, results of the level of Ammonia (NH3) from theinfiltration basin at North Gaza infiltration basin site showed a significant increase especially inyear 2013 and 2014 where the maximum level of Ammonia was 1.83 mg/l and 3.66 mg/l for2013 and 2014, respectively.

This suggests a significant increase (p<0.05) compared with previous years and the 2008baseline year (0.1 mg/l). Moreover, it was noticed that NH3 level for the wells SW, MW4, MW5and Q53, closer to the infiltration basins and lie within a 300m radius from the infiltration basin(Figure 8), is above the allowable limit of food and agriculture organization (FAO) standards forirrigation (5-30 mg/l) after four years of wastewater infiltration (2014) compared with previousyears.

4. Ammonia (NH3)

0

0.4

0.8

1.2

1.6

2

2.4

2.8

3.2

3.6

4

4.4


mg/L

Well Name

2008 2011 2012 2013 2014

This might be due to the high concentration of Ammonia in the BLWWTP effluent in year 2013and 2014 (88 mg/l) compared with that concentration in 2011 (4.5 mg/l)


❷ الترشيحأحواضأنشكلالويوضح

المياهجودةمستوىتدنيفيساهمة

االأمونيتركيزلرفعهانتيجةالجوفية

منبالقربالجوفيةالمياهفي

2013عامفيالترشيحأحواض

2011عامفيعليهكانتعما

المنطقةرقعةوازدياد2012و

.الملوثة


Boron concentration was monitored in the BLWWTP effluent between 2008 and 2013suggesting a fluctuated level of boron where it ranged from 0.31o 0.35 mg/l.

This level may resulted in high Boron in the surrounding wells, with obvious increase in theclosest wells to the infiltration basins. results showed that boron concentration in thegroundwater ranged between 0.02 and 0.05 mg/l in 2008 (before infiltration started) andincreased rapidly to 0.4-1.56 mg/l and 0.3-1.22 mg/l in 2011 and 2013, respectively.

These results reflect the influence of the native groundwater on boron. It suggests that theinfiltration of the wastewater through the sandy aquifer has minimum to no effect on thereduction of Boron level.

5. Boron (Br)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

SW DB4 MW1 MW2 MW3 MW4 MW5 Q15 Q53 Q64 Q20 Q86 IWW

mg/L

Well Name

2011 2013


The study conducted at the DanRegion (WHAT IS THIS STUDY, Givedetails) area, boron was removedduring percolation in the earlystages. However, after severalmonths, boron was graduallyincreased in the recovery wellsuntil it reached the sameconcentration as the effluent(Icekson-Tal and Blanc, 1998)which suggested the deteriorationefficiency of the SAT system.Boron removal was minimal(1.8%) as its level was 0.54 mg/l inthe applied effluent same as thelevel in the groundwater (Hamdanet al., 2011).

25 الخلاصة

Although the quantity of the infiltrated wastewater to the aquifer is currently smallcompared to the basin maximum designed capacity, it has had a slight positive impacton improving the continuous declined water table level as it replenished the aquiferand increased its level by about 1.0-2.0m.

Moreover, infiltrating partially treated wastewater can pose some enhancements orrisks to groundwater physicochemical and biological properties:

The recharged wastewater can improve the quality of the groundwater aquiferonce its primarily quality is better as in the case of chloride and nitrate.

Recharged effluent increased the level of ammonium concentrations in theaquifer representing a challenge for artificial recharge of groundwater under thelocal conditions.

continuous recharge with high concentration of TSS may result in slowing downthe infiltration rate due to clogging and thus early failure of SAT system.

Boron concentration is alarming as it exceeds the FAO recommended value of 0.7mg/l. There might be a need for an early stage treatment for boron before thewastewater being recharged to the aquifer by applying a conventional treatmenttechnologies (metal hydroxide precipitation) to reduce the boron level

25 الخلاصة

However, the decrease in chloride and nitrate concentrations in the recipient aquiferrepresented good motivation to carry on such projects and to take into account the

lessons learned through this project. Care should be taken in applying pre-treatment to eliminate and reduce the unlikely parameters before beingdischarged or infiltrated into the groundwater aquifer.

26 لتوصياتا

أوتحسينيفكبيرتأثيرمنلهالماالأمونياتركيزوخاصةالترشيحقبلالعادمةللمياهالمعالجةجودةتحسين

فيكبيردورمنلهالماTSSتركيزخفضضرورةإلىبالإضافة.المنطقةفيالجوفيةالمياهجودةتدني

.الرشحمعدلانخفاضوبالتاليالأحواضتسديدسرعة

الغربيةالمنطقةفيالآبارعددزيادةالإعتباربعينالأخذمعالحاليالمراقبةبرنامجفيالإستمرار

(downstream)آباروصلاحيةالترشيحنظامكفائةومدىالجوفيةالمياهلجودةالدوريةللمراقبة

إنتشارلمدىوفقا والزراعيالآدميللإستخدامآمنهوالغيرالآمنةالآبارتحديدخلالمنللإستخدامالإسترجاع

.الملوثات

(أبعدمسافةعلى)الحاليةالآبارعليهاالمقامالدائرةمنأوسعقطرهابدائرالمراقبةآبارمنمزيدحفر

.منهاتمرالمسللضخلنظرا ممثلةغيرالزراعيةالآبارأنحيثالجوفيةالمياهلمنسوبأدقمراقبةليتسنى

المنظفاتتركيزفحصضرورة(Detergents)دوريبشكلالجوفيةوالمياهالمعالجةالعادمةالمياهفي.

27 شكر وتقدير

لسلطةيرهاوتقدشكرهابخالصالبيئةجودةسلطةتتقدمكلتوفيرفيالتعاونهالمشاريعوحدة–الفلسطينيةالمياه

انجاحها،و الدراسةهذهلإتماموالتقاريراللازمةالبياناتتعاونوالالموقعفيالعيناتأخذلتسهيلبالإضافة.ذلكفيالمشترك

28

1. Alslaibi, T. M.; Mogheir, Y. In Recent estimations of hydrologic cycle components in Gaza Strip catchment., In:International conference: sustainable development and management of water in Palestine, Amman, , Amman,Jordan, 27–29 August, 2007; Cairo: House of Water and Environment and UNESCO regional office: Amman,Jordan, 2007; pp 421–429.

2. CMWU Annual Report on Water Status in the Gaza Strip; Gaza Strip, Palestine, 2010.

3. Nations, U. Gaza in 2020 A liveable place?; Office of the United Nations Special coordinator for the middleEast Peace Process (UNSCO): Jerusalem, 2012; p 20.

4. Institute of Water and Environment North Gaza Emergency Sewage Treatment Project (NGEST), Aquifer WaterQuality Baseline Survey; Al Azhar University, Gaza, Palestine, August, 2008.

5. ArcGIS Desktop Help ArcMap version 10.1; ESRI: 2010.

6. Institute of Water and Environment North Gaza Emergency Sewage Treatment Project (NGEST), GroundwaterQuality Monitoring; Al Azhar University, Gaza, Palestine, March 2011.

7. Institute of Water and Environment North Gaza Emergency Sewage Treatment Project (NGEST), GroundwaterQuality Monitoring, Fourth Round analysis; Al Azhar University, Gaza, Palestine, February, 2012

8. Environmental and Rural Research Center North Gaza Emergency Sewage Treatment Project (NGEST), WaterQuality Monitoring Survey - NGEST-SH 94 /013, first round analysis; Islamic University of Gaza, Gaza,Palestine, April, 2013.

المراجع

29 الملحق

29

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