1. Optimizing Domestic Wastewater Reuse Options in Agriculture: A Case Study N K Tyagi Former Member ASRB, ICAR
Reduce fresh water use and recycle wastewater

2. Scheme of Presentation
Research background & review
Study area
Optimization model and results
Inferences and way forward
Reduce freshwater use and recycle wastewater

3. CIRCULAR ECONOMY of Wastewater Management(www.wrap.org.uk)
The linear economic model: “develop, , use and dispose”. It relies on large quantities of cheap easily accessible materials and energy.
“A circular economy keeps resources in use for as long as possible…then recovers and regenerates products and materials at the end of each service life”.
Waste water management can play an important role in the emerging circular economy - as huge amounts of “waste” water that is generated is full of material ( recycled water, energy, nitrogen, phosphorus, organic fertilizer) that can be recovered and regenerated.
Reduce fresh water use and recycle wastewater

4. Resources embedded to municipal wastewater(per capita per yr
Parameters
Value
Reusable water ,(m3)
80-120
Cellulose, (kg)
5-7
Biopolymers, (kg/capita year)
2-4
Phosphorus (for incorporation in P compound), (kg)
Nitrogen (for incorporation in N compound) ,(kg)
4-5
Methane, (m3)
12-13
Organic Fertilizer (P-rich compost), (kg)
9-10
Verstraete et al. (2009) Bioresource Technology 100, 5537–5545
Salehizadej and van Loosdrecht (2004) Biotechnology Advances 22, 261–279
Reduce freshwater use and recycle wastewater

5. A strong case for circular economy in wastewater in India 2030 WRG,2016)
Water security parameter
Value
Water availability per capita,
1545 (m3/year)
Groundwater situation
30 % over-exploited
River pollution
91 % of 301 river stretches polluted
Phosphate import
30 % of global import

6. Climate, Water balance and Sewage water Quality at Karnal

7. Agro-climatic water soil-water balance in Karnal
Reduce freshwater use and recycle wastewater

8. Composition of domestic wastewater at CSSRI, Karnal (Pandey et al,2009)
Parameter
Value pH
7.93
P (mg/ l)
4.06
EC (dS/m )
0.98
K (meq /l)
0.29
BODs (mg/ l)
198
Na (meq/ l)
2.38
COD(mg /l)
249
Ca (meq/ l)
2.19
NH4 -N (mg /l)
12.9
Mg (meq /l)
3.20
NO3 -N (mg/ l)
2.43
Zn (mg/ l)
0.24
HCO3 (meq/ l)
7.89
Fe (mg/ l)
0.94
E. coli (100 m/l)
1010
TSS (mg /l)
100
Reduce freshwater use and recycle wastewater

9. Sewage Water Quality in Haryana during Summer(CSSRI,2001)
Constituents
Concentration, (mg/l)
Concentration, (ppm)
Untreated
Treated PH
7.5
8.1 DO
1.8
3.2
EC, dS/m
1.9
1.89 P
5.5
4.5
SAR
3.4
3.9
BOD
239
110
RSC
2.6
COD
240
185 Ca
2.9
NH3-N 30 24 Mg
4.9
3.8
NO3-N 5 K
0.7
0.6 Cd
0.1 Cl
9.1 Cr
0.49 Na 7
7.1 Ni
0.46
0.52

10. Long effect on soil and crop productivity
Soil health
Groundwater quality
Crop productivity
Quality of produce

11. Effect of Sewage Irrigation on Soil Salinity contents of Major Nutrients(Minhas and Samra,2004)
Site & Years sewage use
Treatm-ent pH
(1:2)
EC(1:2)
dS/m
O M
C(%)
Available
N(kg/ha)
P(kg/ha)
K(kg/ha)
Kaithal
(15 years) SI
NSI
7.7
8.4
1.9
3.3
1.3
0.5 70 42 78 30
105 88
Narwana
(12 years)
7.8
3.0
0.8
0.3 57 50 74 4
136
172
Rewari
8.6
8.2
0.7 77 14 16 -
Hissar
8years)
7.5
7.9
0.6 56 49 43 34 81
SI-Sewage irrigation
NSI Non-sewage irrigation Reduce freshwater use and recycle wastewater

12. Effect of long term sewage water use (10 years) on groundwater (Yadav et al,2002
Traces of NO3-N (up to 2.8 mg l(-1)), Pb (up to 0.35 mg l(-1)) and Mn (up to 0.23 mg l(-1)) could also be observed in well waters near the disposal point thus indicating initiation of ground water contamination.

13. Improvement in crop yield with sewage water over fresh water(CSSRI,2004)

14. L P OPTIMIZATION MODEL OBJECTIVE FUNCTION CONSTRAINTSn
Max Z= ∑ Pi Xi
i=1
Pi= Profit from crop activity i ( i=1 ,2,3………..n)
Activities include field crops like, rice, wheat, vegetable with subsurface drip,
forest trees etc, disposal in river/drain
Note: The model is run with and without sewage water; and with and without water treatment
Reduce freshwater use and recycle wastewater
CONSTRAINTS
Crop area: ∑AiXi= TA(Total area)
Crop irrigation water use:
12 n
∑ ∑ IR ij= ∑ (FWj+SWj) ,
j=1 i= j=1
FW=Fresh water Sw=Sewage water, j=Months 1 ,2 ,3 ,…… 12
Sewage water use :
∑SW . Xi ≤ ∑ TSWj
j= j=1
TSW= Total sewage water

15. Options Employed in Sewage Water Use Optimization
Irrigation of field crops
Horticulture with drip system
Forest trees
Disposal in drain/river
Reduce freshwater use and recycle wastewater

16. Utilization of Sewage Water during Different Months

17. Benefits (Rsx106) from Irrigated Cropping with and without Use of Sewage Water in Karnal Sewage Water Channel Command
Alternative
No treatment
Primary treatment
Without consideration of cost due to health hazard
Without sewage water use
14.1
With sewage water use
35.2
30.09
Benefit accruing due to sewage water
21.2
15.99(114 % increase)
With consideration of cost due to health hazard
With consideration for cost on medical expenses and wages loss (Rs.1000/capita/year)
19.8
15.05
There were no reliable estimates of cost of medical expenses. So, primary treatment is advocated

18. Results Highlights
Primary treated wastewater use increased farm profit by 114 % over no wastewater use
On annual basis about 450 tons of nitrogen could harvested from wastewater irrigation, thereby reducing the need for equal amount of chemical fertilizers.
The projected increase in nitrogen concentration after 50 years was only 4.0, and 2.5 mgl-1 for raw and primary treated wastewater, respectively.
Forestry is a good option to dispose surplus wastewater in a controlled manner
Reduce freshwater use and recycle wastewater

19. Inferences and Way Forward (I)
Wastewaters from the municipalities and agro-industries provide nutrients and thus reduce cost of cultivation as well as of the treatment, as land application itself is a treatment method.
The domestic wastewaters can be used for field crops with only primary treatment.
Sub-surface drip system is the preferred option for vegetable crops as it avoids contact with edible components.
Wastewater management promotes circular economy and saves freshwater /energy ,both of which are scarce
Reduce freshwater use and recycle wastewater

20. Inferences and Way Forward(II)
There are research gaps to be filled. Development of comprehensive guidelines, based on climatic conditions, soil type, water table, crops and irrigation technology be evolved.
Facilitation mechanisms to implement circular economy in wastewater management
A coherent national policy that would allow integration of wastewater with waters from other sources
Coordination mechanism: Wastewater collection, treatment, disposal and use involve multiple agencies/departments.
Reduce freshwater use and recycle wastewater

21. Thanks for Your Attention f your attention