This document discusses effluent parameters and treatment methods for waste water from sugar industries. Sugar processing produces large volumes of wastewater with high levels of suspended solids, BOD, COD and sugar. Key effluent parameters include pH 6-10, TSS 150 mg/l, TDS 3500 mg/l, BOD 80 mg/l and COD 150 mg/l. Available treatment options include lagoons, trickling filters, UASB reactors and activated sludge systems. While end-of-pipe treatment is needed to meet standards, in-plant prevention measures can reduce effluents to lower treatment costs. The most thorough and affordable options appear to be sequences of aerobic/

1. EFFLUENT PARAMETERS
& TREATMENT METHODS
OF WASTE WATER
EFFLUENTS FROM SUGAR
INDUSTRIES

2. WATER CONSUMPTIONWATER CONSUMPTION
Sugar processing requires hot water for a number of steps suchSugar processing requires hot water for a number of steps such
as water for imbibition,raw sugar remelting and various washingsas water for imbibition,raw sugar remelting and various washings
– in the amount of approximately 50% by weight of the cane– in the amount of approximately 50% by weight of the cane
crushed. Once steam generation has begun, about 90% of thiscrushed. Once steam generation has begun, about 90% of this
need is met through condensate collection from the evaporatorsneed is met through condensate collection from the evaporators
and overflow from the boiler house. The water content from theand overflow from the boiler house. The water content from the
sugar cane itself also enters into this process. Water exits thissugar cane itself also enters into this process. Water exits this
loop through multiple means – in the filer cake, molasses,loop through multiple means – in the filer cake, molasses,
bagasse and irrecoverable vapors – with the largest portionbagasse and irrecoverable vapors – with the largest portion
going to the drain, in the amount of approximately 90% of thegoing to the drain, in the amount of approximately 90% of the
cane used.cane used.

3. FEED WATER CHEMICAL ANALYSISFEED WATER CHEMICAL ANALYSIS

4. WATER EFFLUENTS:WATER EFFLUENTS:
Wastewater with varying levels of pollution load is generated at nearly allWastewater with varying levels of pollution load is generated at nearly all
stages of sugar production. Cane washing becomes necessary when thestages of sugar production. Cane washing becomes necessary when the
cane is harvested mechanically, generating waste water that has a highcane is harvested mechanically, generating waste water that has a high
concentration of suspended solids and may have a significant sugarconcentration of suspended solids and may have a significant sugar
concentration due to damage incurred by the cane during mechanicalconcentration due to damage incurred by the cane during mechanical
harvesting.harvesting.
Relatively mild effluents from the mill house, containing oil, grease, andRelatively mild effluents from the mill house, containing oil, grease, and
some sugar content, are generated from the lubricating and cooling systems,some sugar content, are generated from the lubricating and cooling systems,
floor washings, the large quantity of water used for juice extraction, andfloor washings, the large quantity of water used for juice extraction, and
some leakage and spillover.some leakage and spillover.
A major source of organic pollutants in the wastewater is entrainment (theA major source of organic pollutants in the wastewater is entrainment (the
absorption of sugar particles into cooling and condenser waters) duringabsorption of sugar particles into cooling and condenser waters) during
evaporation and crystallization processes, which is reduced to some extentevaporation and crystallization processes, which is reduced to some extent
where entrainment separators are used in evaporators and vacuum pumps.where entrainment separators are used in evaporators and vacuum pumps.

5. Washing the filter clothes used for sludge from the clarifierWashing the filter clothes used for sludge from the clarifier
increases the suspended solids concentration and BOD ofincreases the suspended solids concentration and BOD of
the wastewater. In general, sugar mill effluents containthe wastewater. In general, sugar mill effluents contain
acidic and alkaline compounds, a significant concentrationacidic and alkaline compounds, a significant concentration
of suspended solids and a high BOD, COD, and sugarof suspended solids and a high BOD, COD, and sugar
concentration.concentration.

6. EFFLUENT PARAMETERS:-EFFLUENT PARAMETERS:-
1]1] pHpH 6-106-10
2]TSS (2]TSS (mg/lmg/l)) 150150
3]TDS (3]TDS (mg/lmg/l)) 35003500
4]BOD (4]BOD (mg/lmg/l)) 8080
5]COD (5]COD (mg/lmg/l)) 150150
6]Oil & grease (6]Oil & grease (mg/lmg/l)) 1010
7]Temperature7]Temperature 404000
CC

7. WASTE WATER TREATMENT:-WASTE WATER TREATMENT:-
Available end-of-pipe effluent treatment options include the use of Lagoons,Available end-of-pipe effluent treatment options include the use of Lagoons,
Trickling filters, Upflow Anaerobic Sludge Blanket (UASB) reactors, andTrickling filters, Upflow Anaerobic Sludge Blanket (UASB) reactors, and
Activated Sludge Treatment (sequential batch reactors).Activated Sludge Treatment (sequential batch reactors).
With decreasing land availability, in-house measures producing lessWith decreasing land availability, in-house measures producing less
voluminous wastewater with stronger BOD requiring more expensive lagoonsvoluminous wastewater with stronger BOD requiring more expensive lagoons
and ponds, and the problem of ground water contamination, less land-intensiveand ponds, and the problem of ground water contamination, less land-intensive
and more efficient systems may be needed in the future such as the activatedand more efficient systems may be needed in the future such as the activated
sludge process.sludge process.
Activated sludge systems have the highest energy requirement for aerationActivated sludge systems have the highest energy requirement for aeration
which drives up operation and management costs. However, costs can bewhich drives up operation and management costs. However, costs can be
reduced by using this as a secondary treatment after effluents have beenreduced by using this as a secondary treatment after effluents have been
treated with Upflow Anaerobic Sludge Blanket (UASB) technology. The UASBtreated with Upflow Anaerobic Sludge Blanket (UASB) technology. The UASB
system, a much cheaper option because it only requires energy to run a fewsystem, a much cheaper option because it only requires energy to run a few
aeration pumps, can potentially remove up to 80 – 90 % of the BOD.aeration pumps, can potentially remove up to 80 – 90 % of the BOD.

8. Nonetheless, end-of-pipe treatment, though will require aNonetheless, end-of-pipe treatment, though will require a
large capital investment and substantial maintenancelarge capital investment and substantial maintenance
costs, will eventually have to be adopted to bring the sugarcosts, will eventually have to be adopted to bring the sugar
industry in compliance with the defined standards.If theindustry in compliance with the defined standards.If the
sugar mills are vigilant with the in-plantsugar mills are vigilant with the in-plant
pollution prevention measures, the wastewater can bepollution prevention measures, the wastewater can be
substantially reduced rendering the requisite end-of-pipesubstantially reduced rendering the requisite end-of-pipe
treatment much less costlier than the scale of treatmenttreatment much less costlier than the scale of treatment
that would be needed to mitigate current effluent levels.that would be needed to mitigate current effluent levels.
From the various options available, sequences of aerobicFrom the various options available, sequences of aerobic
and anaerobic lagoons or a combination of UASB reactorand anaerobic lagoons or a combination of UASB reactor
and activated sludge system appear to be the mostand activated sludge system appear to be the most
thorough and affordable options.thorough and affordable options.