Anbil Dharmalingam Agricultural College and Research Institute, Tamil Nadu Agricultural University, Trichy 620 009, T.N., India
To monitor the downward movement of post bio-methanated distillery effluent (PME) and possible ground water contamination, piezometers were installed at different depths viz., 0.5, 1.0, 1.5 and 2.0 m in the long term sugarcane field experiments being conducted at EID Parry (I) Ltd., Cane farm, Edayanvelli, Tamil Nadu. The piezometers were installed in pre-plant undiluted PME (5 lakh litres ha-1) applied field, diluted PME (1:10 times) applied field and in control plot (without PME application). Three replications were maintained for each treatment. Piezometers were examined for the presence of leachate every month. The leachate samples were analyzed for pH, EC, cations, anions, sodium adsorption ratio (SAR), residual sodium carbonate (RSC), biological oxygen demand (BOD) and chemical oxygen demand (COD). The analysis of the leachate samples revealed no change in color at all the depths. The BOD and COD of the leachate from PME plots when compared to the control plots were not affected significantly at all the depths. There was not any significant difference observed in the pH, EC, cations like Ca, Mg and K and anions like Cl, CO3, HCO3 and SO4 in the leachate collected beyond 1.5m depths in treated plots when compared to the control plots. The SAR calculated at 0.5m and 1.0m depths of treated plots has stood below the control values. The higher Ca and Mg in the leachate supplied by the PME applied have significantly decreased the SAR of the leachate at these depths. The SAR of leachate collected at 2.0 m depths in the treated plots did not show any significant difference from the control plots. The RSC calculated was found to be lesser than the control plots till 1.0m depths this is due to the higher Ca and Mg found in the leachate. The results reveal that the PME application has not influenced the leachate collected at 1.5m and 2.0m depths in the treated plots and this clearly indicates that PME applied at the highest concentrations has not influenced the ground water and there is no possibility of pollution by the PME application at these doses.
Keywords |
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Distillery effluent, Ground water, Physico-chemical parameters |
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INTRODUCTION |
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At present, there are 319 distilleries in the India with an installed capacity of
3.25 billion litres of alcohol (Uppal, 2004). The cane-growing states of Uttar
Pradesh and Maharashtra have the highest installed capacity constituting
more than 40% of the total installed capacity followed by Madhya Pradesh
(14.2%) and Tamil Nadu (9.7%) (Uppal, 2004). The disposal of wastes from
industrial sources is becoming a serious problem throughout the world. Most
of the distilleries are concentrated in the states of Maharashtra, U.P, Andhra
Pradesh, Madhya Pradesh, Tamil Nadu and Karnataka. The post biomethanated
distillery effluent (PME) released by the distilleries is generally
characterized by high levels of biological oxygen demand (BOD), chemical
oxygen demand (COD) and electrical conductivity. Owing to its high nutrient
potential and organic carbon it is widely recycled for augmenting crop production
in the sugar industries command area (Joshi et el. 1996). However, indiscriminate
disposal of this PME has resulted in adverse impact on soil and
environmental health in various areas. Ground water contamination by effluent
with high BOD and salt content near the lagoon side in the most of the
distilleries has been reported widely. In some cases, particularly in Maharashtra
the color problem in groundwater is so acute that distilleries have to provide
separately potable water to surrounding villages (Nemade, 2002). Hence a
study was initiated to monitor the downward movement of PME and possible
ground water contamination. |
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MATERIALS AND METHODS |
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To monitor the downward movement of PME and possible ground water contamination,
piezometers were installed at different depths viz., 0.5, 1.0, 1.5 and
2.0 m in the long term field experiments (sandy loam soil) being conducted at
EID Parry (I) Ltd., Cane farm, Edayanvelli, Tamil Nadu. The piezometers were
installed in the treatments of the long-term experiments that received pre-plant
undiluted PME @ 5 lakh litres ha-1, diluted PME @ 1:10T (4 Lakh litres ha-1) and
in control plot (without PME application). Piezometers were installed in three
replicates in their respective treatmental units. |
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Piezometer installation |
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Four nested piezometers of different lengths (0.5m, 1.0m, 1.5m, and 2.0m) were installed in the long-term experimental plots to measure the shallow and deep
ground water to confirm the nutrient distribution. A hand augur was used to
dig holes for each piezometer. The piezometers were made from slotted PVC
pipes that were covered with mesh at the base, and then inserted into the
augured holes. The space around the tubes were backfilled with sand till the
level of holes and then with white cement and followed by clay to prevent
preferential flow pathways developing around the outsides of the PVC tubes.
PVC tubes extend above the soil surface for 1m to avoid surface water flow
entering the piezometers. They were end capped to avoid rain filling the tubes
shown in Fig 1. The designs of the piezometers are prepared based on the
models of nested piezometers by Aarons et al. (2004). |
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Sampling and analysis |
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Piezometers were examined for the presence of leachate every month. However
leachate got collected in the piezometers only during the rainy months (only
after heavy rains). The leachate samples were analyzed for pH, EC, cations,
anions, SAR, RSC, BOD and COD. Analysis was done according to standard
water analytical procedures (APHA, 1998). The analyzed results data were
statistically scrutinized (Gomez and Gomez, 2000). |
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RESULT AND DISCUSSION |
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Influence on pH and EC |
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The pH and EC of the leachate collected at 0.5m and 1.0m depths in the PME
plots has shown a slight increase over the control plots, indicating the PME
influence on the leachate at these depths (Table 1). The leachate at 1.5m, and
2.0 m depths has not shown any significant difference from control plots indicating
that there is no significant downward leaching of soluble salts below
1.0m depths. Electrical conductivity is an indirect measure of soil and soil pore
water salinity. The electrical conductivity of the subsurface generally depends
on the soil texture, soil chemistry, water content, soil porosity and pore water
quality (MacMillan, 2001). |
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Influence on cation concentrations |
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The leachate collected was analysed for cations like Ca, Mg, Na and K. The
analysed calcium content of the leachate has revealed that there is a significant
increase in calcium levels upto 1.0m depths in the treated plots when compared
to the control plots. This might be the influence of applied PME. The
calcium content of the leachate collected from the 2.0m depths of PME plots has
not shown any significant difference from the control plot values implying that
there is no impact by the applied PME. |
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The magnesium and sodium content of the leachate analysed has shown
significant difference from the control plots only at 0.5m and 1.0m depths in
the treated plots and there is no significant difference observed at 1.5m and
2.0m depths in treated plots suggesting the impact of applied PME only till
1.0m depths. |
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The leachate analyzed for potassium content at different depths for the two
doses has revealed that the potassium content of the leachate from PME plots at 0.5m and 1.0m
depths was found to be
significantly higher
than the control plots.
The higher value suggests
that the PME with
its high K content has
enriched the surface
layers and the potassium
from the surface
layers has leached
down till 1.0m depths.
The K content of the
leachate obtained at
1.5m and 2.0m depths
in treated plots has revealed
that the K has
not leached more than
1.0m depths and
thereby has not influenced
the water quality
more than 1.0 m
depths. The K movement
in the soil water
was reported by van
Noordwijk (1999). |
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Influence on anion
concentrations |
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The leachate was analyzed
for anions like
chloride, carbonate, bicarbonate
and sulphate.
The leachate
from PME plots has
shown a higher chloride
content at 0.5m
and 1.0m depths than
the control plots. While
the chloride content at
1.5m and 2.0m depths
has not shown significant
difference from the
control plots. Dawes et
al. (2001) has used chloride
concentration as
an indicator of effluent
movement because it is highly mobile in soil systems and undergoes limited soil adsorption and no
biochemical transformation. |
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The carbonate content of the leachate from PME plots has not shown much
difference from the control plots and was under safer limits in all the samples
collected at different depths. The bicarbonate content of the leachate at 0.5m
depths of PME plots stood above the control plot values confirming the leaching
of bicarbonates as Ca and Mg bicarbonates. The higher Ca and Mg at this
depths correlates with the observations. The bicarbonate levels at 1.0m, 1.5m
and 2.0m depths have not shown significant difference from the control. |
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The sulphate content of the leachate at 0.5m and 1.0m of PME plots stood
higher than the control plot values and there was not much difference observed
at 1.5m and 2.0m depths when compared with the control plot. |
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Influence on sodium adsorption ratio and residual sodium carbonate
sodium adsorption ratio |
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The SAR calculated for the leachate samples collected from the piezometers at
different depths revealed that there is significant influence by the applied PME
till 1.5m depths. The SAR calculated at 0.5m, 1.0m, and 1.5 m depths has stood
below the control. The higher Ca and Mg in the leachate supplied by the PME
applied have significantly decreased the SAR of the leachate at these depths.
The SAR of leachate collected at 2.0 depths did not show any significant influence
by the PME this is evident from the values of the control and the treatment
samples. |
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Residual sodium carbonate |
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The Residual Sodium Carbonate calculated revealed that the calcium and magnesium
leached from the surface layers from PME applied plots till 1.0m depths
has decreased the residual sodium carbonate of the leachate from these plots
when compared to the control. The calcium and magnesium has not leached significantly below 1.0m depths and this is evidenced from the calculated calcium
and magnesium contents and from the calculated RSC from the leachate
at 1.5m and 2.0m depths. |
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Influence on BOD and COD |
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The leachate analyzed for the BOD and COD revealed that the PME applied
has not significantly affected BOD and COD of the leachate when compared to
the control at all the depths. |
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CONCLUSIONS |
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The intensive water sampling and the piezometer data demonstrated elevated
nutrient levels in the leachate collected at 0.5m and 1.0m depths of treated
plots, also there was no impact of the PME on the leachate observed beyond
1.5m depths of treated plots. The results of monitoring at the highest dose has
clearly evinced that the recommended dose of 1:10T dilution treatments as
fertigation and 1.25 lakh litres per hectare as preplant application of post biomethanated
distillery effluent is the optimal dose and they do not pose any
possibility of pollution of ground water in near future. |
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ACKNOWLEDGEMENT |
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The authors express their sincere thanks to M/s EID Parry (I) Ltd. Nellikuppam
for the financial assistance and laboratory facilities provided by them to
carryout this research successfully. |
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References |
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