Case studies on Sludge and water management

Transcription

1 Case studies on Sludge and water management Sujit Kumar Singh

2 Big question???????? Do we know that how much sewage we generate Do we know that HOW MUCH INDUSTRIAL EFFLUENT WE GENERATE DO we have updated information (Yes/no)

3 Sewage generation According to CPCB report ( ) approximately MLD sewage is generated in India including all the Metropolitan, Class1 and Class 2 cities and only MLD of this is treated (around 37%) before being discharged into the water bodies. According to CPCB, the total wastewater discharged by all major industrial sources is 83,048 million litres per day (mld)

4 Why we do Wastewater Treatment? To meet the regulatory standards Conventional treatment removes BOD and SS but unable to remove nutrients and complex compound. Decreasing assimilative capacity of water bodies Water scarcity also pushed industry to opt for advanced wastewater (Recycle and Reuse)

5 How we can achieve Understand - wastewater characteristic Estimate the Quantity of wastewater generation Check potential of segregation (process & utility) Selection of appropriate technology

6 Approach for wastewater Treatment Wastewater Treatment Urban Centralized Industrial Decentralized Centralized Decentralized STP Natural process

7 Characteristic of Sewage

8 Wastewater Treatment Wastewater treatment mainly consists Preliminary treatment Primary treatment Secondary or biological treatment Advanced treatment

9 Types of Solids Suspended solid or filterable solid floating solid (> 1 micron) Settleable solids settled down after providing DT ( > 10 micron NO Coagulant, < 10 micron Coagulant is required)

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11 Types of Solids Colloidal solids fine solids either in solution or in suspension (< 1 micron to 10-3 micron) Dissolved solid in dissolved state (less than 10-3 micron)

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14 Class exercise on DO Assume 2.5 ml of raw sewage diluted to 250 ml Initial DO was 8 mg/lit Final DO was 5 mg/lit at three days at 20 C Estimate BOD in mg/lit in wastewater

15 Dilution ratio = 250/2.5 = 100 Loss of dissolved oxygen = 8 5 = 3 mg/lit BOD = loss of oxygen x dilution factor = 3 x 100 = 300 mg/lit

16 Class exercise Total sewage coming to STP = 95 MLD Average BOD of untreated waste water is 300 mg/lit Estimate total population discharging ww (assume BOD of sewage 0.08 kg/day/person

17 Solution Total organic load = 300 mg/lit x 95 MLD = (300 x 95 x )/ (1000 x1000) = 300 x 95 = kg/day Population equivalent = (Total BOD in kg/day)/ (Per capita BOD in kg/day/person)

18 Waste Stabilisation Ponds Organic matter degradation by heterotrophic bacteria Algae growth cause decomposition, leading to production of oxygen. Replenish O2 in the pond and maintain aerobic condition Microbes grow as suspended particles.

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20 Waste Stabilisation Ponds Robust and withstand hydraulic and organic shock load Effluent from maturation pond can be used for agriculture and aquaculture Very low O&M cost

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22 Activated Sludge Process ( ASP ) Primary wastewater mixed with bacteria-rich (activated) sludge and air or oxygen is pumped into the mixture Promotes bacterial growth and decomposition of organic matter Last step is a settling tank where sludge settles out and then the treated wastewater moves on for tertiary treatment. Some settled sludge is used to inoculate incoming primary effluent. Features High BOD removal Microbial removal: Energy intensive

23 Aeration tank Final clarifier

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29 Movie microbes

30 Method of Aeration in ASP Diffused aerator Mechanical aerator Combination of both Average = 4000 to 8000 m3 of air is required per million liter of sewage (depend of strength of sewage)

31 Design criteria Volume of return activated sludge - depend of extend of BOD desired to be removed = i.e. (Qr/ Q), where Qr return sludge and Q volume of sewage coming in AT As thumb rule quantity of return sludge is 35 to 55 % of volume of sewage coming in AT

32 Design criteria Important terms (1) Aeration period or HRT DT (hr) = Volume of tank/ rate of flow of sewage

33 (2) Volumetric BOD or organic loading BOD load applied per unit volume of aeration tank = Mass of BOD applied per day to AT/ Volume of tank (m3) = (Q x inlet BOD)/ volume

34 (3) Food (F) to microorganism (M) ratio Food = Q x inlet BOD to AT Microorganism (M) = MLSS x volume of tank

35 OXYGEN REQUIREMENT AND TRANSFER Depends on BOD of wastewater Amount of organisms wasted per day Minimum oxygen level of 1 to 2 mg/l in Aeration Tank For F/M ratio of 0.3, air requirement is 30 to 55 m3/kg of BOD removed

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38 Sludge digestion Sludge from primary and secondary settling tanks (including waste activated sludge must be treated in digesters. Sludge is thickened before passing into the digesters Sludge is treated anaerobically; Methane production takes place. Biogas is used as fuel.

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42 Membrane Bio-Reactors (MBR) Combination of membrane process like micro-filtration or ultrafiltration with suspended growth bio-reactor. Pore size of filter used: micrometer. Provide better biodegradability and cell synthesis.

43 Difference between ASP and MBR

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45 Membrane Type - microfiltration, ultrafiltration Can operate at high MLSS concentration upto 15,000-25,000 mg/l

46 Comparison of MBR Schematic Vs convention AS Process

47 Configurations include internal MBR and external MBR. Produces high quality effluent with a relatively small footprint. Old plants can be retrofit, easily upgraded to MBR.

48 Advantages Can eliminate secondary clarifier and operate at higher MLSS concentration. Higher volumetric loading rates; thus shorter HRTs. Longer solids retention time resulting in less sludge. Operate at low DO with potential of simultaneous nitrification-denitrification in longer SRT designs. Less space requirements: saves land costs; facilitates upgradation of old plants.

49 Disadvantages High capital costs. Limited data on membrane life. Potential high cost of periodic membrane replacement. Higher energy costs. Need to control membrane fouling.

50 Features of MBR BOD removal 95%. Can be increased up to 96-99%. Effluent TSS is very low, Total P <0.1mg/l and extensive Total N removal.

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52 MBR at ITC Maurya, New Delhi Kitchen waste Installed Capacity: 800 KLD Total capital investment: 2.5 crores O&M cost : Rs 20/KL Grease Traps(10) Equalization tanks with blowers Treated water KLD to cooling towers Bar screens (3) KLD for horticulture purposes 10-15KLD to fountains make up water MBR Softner KLD to NDMC for Horticulture

53 Moving Bed Biological Reactor (MBBR) Aeration is done in such a way to ensure thorough mixing and proper turnover of the media within the reactor. Efficient removal of carbonaceous and nitrogenous waste.

54 Reactors are filled with plastic carriers to provide surface

55 Screens are placed on the downstream walls, to prevent media from flowing out

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57 Clarifier or DAF is placed at the downstream to separate the biomass. No sludge recycle is required. During operation, carriers are kept in constant recirculation. In aerobic: through introduction of air by coarse air bubble diffuser. In anoxic, through submerged mixers. Carriers can occupy upto 50 to 70% of reactor volumes.

58 Advantage : MBBR Robust: Stable under load variation and provides consistent treatment results. Compact: typically requires 1/3rd of the space for a conventional AS process. Cost: Low capital costs similar to AS. Flexible: Existing plants can be upgraded with an MBBR. Trouble free: Easy to operate, and no issues of media clogging

59 Sequencing Batch Reactor (SBR)

60 Sequencing Batch Reactor (SBR) It is a single reactor which operates in a batch treatment mode repeating a sequence continuously. It is a fill & draw activated sludge system Reaction & Settling takes place in the same reactor

61 It comprises of four phases. i. ii. iii. iv. Filling Aeration & Reaction Settling Decanting

62 Step 1 : Filling

63 Step 2 : Aeration & Reaction Aeration time depend on size & Wastewater quality; typically is min. Higher time upto 3 hr. required for nitrification. Phosphorus removal is aided by adding aluminum sulphate (alum).

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65 Step 3: Settling Usually same time as that of aeration Aerobic bacteria continues to multiply till DO is used up. Conditions are now suitable for anaerobic bacteria to flourish (especially near tank bottom).

66 Step 4: Decantin The outlet valve opens and the clean supernatant liquor exits the tank Decanter

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68 Delawas Jaipur - Waste to Energy STP STP commissioned in 2006, capacity of 62.5 MLD Based on aerobic biological process (ASP) with diffused aerator Waste to Energy made STP self sufficient (75% energy demand)

69 Salient Features of MLD STP

70 Advantage Prior commissioning of biogas plant = average monthly power consumption was Kwh /month (grid) After power generation at plant site from December, 2009 to April, 2012, the average power consumed from grid is only Kwh/month (73% from biogas and rest from grid)

71 Thumb Rule (conventional ASP) Average consumption of new plant Kwh/MLD of sewage treated Old plant Kwh/MLD New plant Kwh/Kg of BOD removed Thumb Rule approx 100 MLD capacity plant = potential to produce 1 MW Note: Power consumption accounts for almost 75% of the expenditure on O and M of any sewage treatment plant

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73 Cost of ASP Land requirement (hectares/mld installed capacity) = 0.15 to 0.25 O&M cost (million/year/ MLD installed capacity) = Rs 0.3 to 0.5 Capital cost (million /MLD capacity) = Rs 2 to 4

74 Surat - Biogas to Energy generation

75 Gas Characteristic

76 Economic

77 Case study Delhi STP 45 MGD sewage treatment plant (STP) at Kondli producing = 10,000 kwh At Okhla STP, 12,000 KWH and at Rithala STP 20,000 KWH Delhi produces 3800 MLD sewage = potential to produce = 38 MWh

78 Coal-based Power Sector

79 Water stress power plant location

80 Water Consumption Water: 70 % of the total withdrawal by industries ~22 BCM Excess water consumption: Avg 4m3/MWh; Best ~2m3/MWh; Worst ~10m3/MWh A survey conducted by FICCI and Columbia University Water Center reveal that ~ 87% of companies believe that water availability will impact their business over the next decade.

81 News from Maharashtra Due to severe water shortage - All six units of Parli thermal power plant shut down (Beed district of Maharashtra) February (2013), resulting in a loss of revenue from stoppage of generation units During the recent drought in Maharashtra, power plants came in for severe criticism with regard to their water consumption Nashik Municipal Corporation has committed to provide treated sewage water (~190 MLD) instead of freshwater for the upcoming 2x660 MW power plant of India Bulls. Requires additional investment for water treatment for input to power plant

82 Class exercise Estimate the water requirement, if the capacity of plant is power plant (coal) 1000 MW Assume 4 to lit/kwh, closed loop

83 Question Consider the scenario of a 1,000 MW power plant shutdown its operations for one day due to unavailability of water Question - Potential revenue loss (assuming Rs 3/unit)

84 Pulp & Paper Case study TNPL Paper mill Water consumption in = 200 m3/paper In 2013 water consumption reduced to 58 m3/tonne product (70% reduction) In May June, specific water consumption dropped to as low as 34 m3

85 Biogas generation from Wastewater Bagasse received from sugar mill having 3-4% residual sugars is stored in the open yard by wet bulk storage method for a period of 3 to 9 months. During storage, the bagasse is kept under wet condition by spraying water over bagasse pile to preserve bagasse quality. TNPL is using nearly 9000 M3 fresh water/treated effluent in the bagasse handling and storage area. Paper machine wastewater, which contains relatively low TDS, was use Waste water generation = around 10,000 to 14,000 m3 of wastewater from Bagasse storage yards and Bagasse washing

86 Flow diagram water use for wetting bagasse Paper machine wastewater Fresh water Clarifier Before Project After Project Fresh water saving 3000m3/day : ETP ETP Legend : Bagasse storage & washing

87 Water characteristic and biogas generation

88 Bio--methanation Plant Bio Lime-Kiln Gas Holder UASB Reactor A UASB Reactor B MOL Tank Bagasse. Wash Effluent Equal. Tank Sludge for Disposal Neutral. Tank Decanter Centrifuge Clarifier Sludge Pit Buffer Tank To Activated sludge process Nut. Tank

89 Project cost was Rs.4.00 crores.

90 Gas firing in Lime Kiln

91 Economic and pollution reduction benefit Particulars Units COD Treated MT / Yr COD Reduced MT / Yr Biogas generation M3 / Yr Furnace oil saving KL / Yr 5798 Revenue from Rs. (in Million) Furnace Oil Saving 265.9

92 Reducing water tread in Pulp & Paper

93 Specific water consumption

94 Specific water consumption in Indian steel plants is compared to the global average of water consumption

95 Case study: Reuse of Bangalore Sewage at Airport The STP plant at Yelahanka, treats 10 MLD of sewage water, and gets Rs. 22, 00,000 every month by selling the tertiary treated water to industries like Bharat Electronics Limited and Bangalore International Airport

96 Case study : Ganga Ram Hospital - Recycle and reuse of hospital water for flushing and gardening Collection Tank Aeration Tank Secondary Settling Tank Chlorine Contact Tank Sludge Holding Tank To Sludge Disposal Pumps / Filter press Note: Planning to use treated water in cooling towers of air-conditioning plants by installing softeners Multi Grade Filter Activated Carbon Filter Treated Water Tank Ozonator Treated Water

97 MBR at ITC Maurya, New Delhi Kitchen waste Installed Capacity: 800 KLD Total capital investment: 2.5 crores O&M cost : Rs 20/KL Treated water KLD to cooling towers KLD for horticulture purposes 10-15KLD to fountains make up water Grease Traps(10) Equalization tanks with blowers Bar screens (3) MBR Softner KLD to NDMC for Horticulture

98 Recycle and reuse of wastewater in vehicle wash facility of TATA Motors, New Delhi, India

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100 Minimum criteria for wastewater treatment

101 The combined approximate cost of construction of mud separator (grit chamber) and oil/ grease trap is around Rs. 7 per litre. For example, if vehicle wash operator wants to treat 1 KL of wastewater per day, the construction cost will be around Rs. 7,000. See Flow diagram for Zero discharge

102 Effluent Treatment Plant and parameters dyeing, printing cotton and blended textile products

103 Effluent Treatment Plant and parameters Garment Washing Unit

104 Flow diagram to achieve zero discharge in a textile plant

105 Case Study 1: Zero discharge in Ranbaxy

106 Step 2: Technology selection based on effluent characteristic

107 Case Study 2: Zero discharge in Dr. Reddy s Laboratories

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109 SUGAR & DISTILLERY SUGAR INDUSTRY DISTILLERY INDUSTRY Sujit Kumar Singh, Programme Manager, CSE

110 Sugar An Eco-Friendly Industry What we take and What we Give back Sugar Cane Sugar Mill Bagasse Sugar Refined Sugar Molasses Press Mud Powe rpower Plant Rectified Spirit Absolute Alcohol ENA Distillery Waste Water / Spent Wash Ash Bio-compost Manure Organic Manure Plant & Biocompost

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112 Indian Sugar Industry at a glance Sr. Particulars Crushing Season No. of Sugar Factories in Operation E Crushing Capacity (million TCD) Sugarcane Crushed (million tons) Sugar Produced (million tons) Recovery % Cane Yield of sugarcane (tons per hectare) Molasses Production (million tons)

113 Raw material Sugar mills consume large quantity of water; the water consumption can be brought down to 100 litres per tonne (L/T) of cane crushed by recycling cooling and condensate Two type of water is used Cold and hot condense water (used as boiler feedback water, juice dilution, lime and sulphate preparation, dilution, molasses conditioning, etc. Recycling and reuse of hot condensate water can reduce the water consumption to as low as litres, as against 1,500-2,000 litres per tonne of cane crushed

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115 SUGAR INDUSTRY BY-PRODUCTS ; EFFLUENT STREAMS ; TREATMENT & UTILIZATION 1) BAGASSE : a) PRODUCED ABOUT 27-30% OF CANE CRUSHED ; CONTAINS 50% MOISTURE ; 50% SOLIDS, MAINLY FIBRES b) CALORIFIC VALUE OF Kcal /Kg c) COMPLETELY CONSUMED IN OWN STEAM & POWER GENERATION d) REQUIRES LARGE STORAGE AREAS ; CAN BE PROCESSED INTO CUBICAL BLOCKS FOR LONGER & COMPACT STORAGE. 2) PRESS MUD : a) PRODUCED ABOUT 4-5% OF CANE CRUSHED ; CONTAINS 60% MOISTURE ; 40% SOLIDS, MAINLY MUD & WAX. b) EARLIER USED TO BE SENT BACK TO SUGARCANE FIELDS AS IS. c) PRESENT USEAGE IN BIO-COMPOSTING; VALUE ADDITION IN TERMS OF N:P:K VALUE USING TREATED MOLASSES SPENT WASH IN DISTILLERIES. FORMS BIO-FERTILIZER & USED MORE EFFECTIVELY BACK IN SUGARCANE FIELDS.

116 SUGAR INDUSTRY BY-PRODUCTS ; EFFLUENT STREAMS ; TREATMENT & UTILIZATION 3) MOLASSES : a) PRODUCED ABOUT 4.5-5% OF CANE CRUSHED ; CONTAINS 20% MOISTURE ; 80% SOLIDS, 38-45% FERMENTABLE SUGARS b) OTHER SOLIDS INCLUDE UNFERMENTABLE SUGARS & CHEMICALS ADDED IN SUGAR MILLS INCLUDING CaCO3, MgSO4, Sulphur, Etc. c) MAY CONTAIN VOLATILE ACIDS DUE TO FORMATION OF WEAK ACIDS DURING LONG STORAGES. d) COMPLETELY CONSUMED IN DISTILLERIES FOR ALCOHOL PRODN. e) REQUIRES CLOSED TANK STORAGE ; CONSTANT COOLING ARRANGEMENT ; VALUABLE BY-PRODUCT. 4) BOILER ASH : a) BOILER ASH, GENERALLY 2% OF BAGASSES USED, IS PASSED THROUGH WET SCRUBBER SYSTEM & SLAG IS REMOVED & STORED IN SILOS. LATER IT IS SENT FOR LAND FILLING APPLICATIONS IN PRE-IDENTIFIED LOW LINE AREAS. THIS SMALL QUANTITY IS ALSO UTILIZED ALONGWITH PRESSMUD IN BIO-COMPOSTING PROCESS.

117 Characteristics of Combined waste Water Parameter Range of Value Temperature, ( C) PH Dissolved solids Suspended Solids Oil and Grease 5-10 COD BOD

118 Class exercise pls suggest treatment option

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121 ALCOHOL PRODUCTION IN INDIA : 2600 MILLION LITERS USE OF ALCOHOL : A) INDUSTRIAL USE ALCOHOL BASED CHEMICALS (25%) : 650 ML B) FUEL ETHANOL ABSOLUTE ALCOHOL (25%) : 650 ML C) POTABLE ALCOHOL EXTRA NEUTRAL ALCOHOL (50%) : 1300 ML

122 ALCOHOL PRODUCTION IN INDIA : 2600 MILLION LITERS RAW MATERIALS : A) MOLASSES FROM SUGAR MILLS (80%) : B) GRAINS / STARCH BROKEN/DAMAGED/SPOILT (19.8%) : C) CANE /SWEET SORGHUM JUICE FUEL ETHANOL (0.2%) :

123 I) MOLASSES BASED DISTILLERIES BROAD CLASSIFICATION A) SUGAR MILL ATTACHED DISTILLERIES OWN MOLASSES & PRESS MUD B) STANDALONE DISTILLERIES PURCHASED MOLASSES & PRESS MUD II) GRAIN BASED DISTILLERIES CLASSIFICATION A) STARCH BASED DISTILLERIES HAVE OWN STARCH SURPLUS B) GRAIN BASED DISTILLERIES BROKEN GRAINS

124 Case study : Rega distillery in Bihar Mill was surveyed by CSE in 2008 Survey finding Illegal discharge of Spent Wash in the river Illegal dumping of Spent Wash on private land and along road side within 5 km

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126 Illegal discharge of spent wash on private land

127 Illegal discharge of spent wash on private land/govt land

128 Illegal discharge of spent wash in low lying area

129 Dead frog impact due to discharge of spent on land

130 Dead frog impact due to discharge of spent on land

131 Industry discharge wastewater in river during night

132 Dead Snake impact due to Centre for Science and Environment illegal discharge of spent

133 Bird carcass due to illegal discharge of spent on land

134 Illegal discharge of spent wash in river during night: impact on water river characteristic

135 Industry discharge wastewater in river during night

136 Industry discharge wastewater in river during night

137 Illegal discharge of spent wash in river during night: impact on water characteristic

138 People complain about cattle death and skin infection

139 Molasses, a by-product of sugar industry used as raw material. The molasses contains about 40-50% sugar, which is diluted to bring sugar contents to 10-15%.

140 In India, alcohol is manufactured by two processes Batch process Continuous process

141 Water requirement Water consumption - 25 to 28 lit/lit of alcohol New 22 lit/lit of alcohol, after adopting recycle and reuse water consumption gone down to 15 lit/lit of alcohol Starch/grain (old) lit/lit of alcohol, after adopting recycle and reuse water consumption gone down to 13 to 15 lit/lit of alcohol

142 Wastewater sources Sources of wastewater for molasses based distilleries Process waste streams Spent wash from the analyser column Fermenter sludge Spent lees from the rectifier Non-process waste streams Cooling water Waste wash water Water treatment plant wastewater Boiler blow down Bottling plant wash wastewater Other wastes

143 Characteristics of Spent Wash from Various Types of manufacturing process

144 Process Stream Discharge from Distilleries Based on Molasses

145 Spent wash

146 Ferti-irrigation Biomethanation aerobic treatment -- effluent should not exceed 500 mg/l -- diluted with freshwater prior to irrigation (100 mg/lit) Disadvantage: Requires large land area and fresh water for dilution, pose risk of ground water pollution Requires proper monitoring and supervision Past experience were not satisfactory For example, a plant of capacity 30 kld alcohol production will requires 270 ha of minimum land for irrigation. Many state pollution control boards are prohibiting this method

147 Treatment, Recycle & Reuse A. Spent wash Cane Molasses Option I : Biomethanation & BioComposting Route Spent Wash Biodigester Bio -Composting % Recycle To Fermentation (Depends on Molasses Quality) Spent Wash Bio-digester RO/Evapn Bio -Composting % Recycle To Fermentation (Depends on Molasses Quality) Discharge of Effluent in Surface Waters is achieved CentreHence, for ScienceZero and Environment

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149 Bio-digester

150 RO PLANT YASHRAJ Alcohols (MAH)

151 1 kg of press mud absorb 2.5 to 3 lit of spent wash 60% distillery in India adopted this method

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154 Bio-composting

155 Bio-composting

156 Bio-compost Bagging

157 CALCULATION OF COMPOSTING CRITERIA: Press mud/spent wash ratio= 1:3 Thumb rule on 1 Acre land = 850 T press mud can be laid down Maximum = 5 cycle /year (No Composting rainy season) 1 cycle = 60 days EXAMPLE 40 KL/day Distillery Spent generation 40 x 12 = 480 KL/day For 1 cycle, spent wash required 60 x 40 x 12 KL Press mud required (60 x 40 x 12 ) /3 T = 9600T

158 To lay down 9600T press mud on land,area required = 9600/850 =11.29 Acre land 30% more land required for finished product as well as press mud storage = 3.5 acre Total Land = = 15 Acre If R.O is used = 7.5 Acre land is required

159 Q1. There is 30KL /day Alcohol production in distillery attached to a sugar factory of capacity 2500 T/day, The factory has 10 acre land. What shall be choice of distillery to treat the spent wash? Q2. There 50 KL/day alcohol production in a distillery, there is a sugar factory of capacity 5000T/day. The factory has 15 Acre extra land. What shall be the choice of a distillery to treat the spent wash?

160 Solution: Problem1: Spent wash = 30 x 12 = 360 KL/day 60 days is one cycle for composting,spent wash= 60 x 360 Kl 1 acre land = 850 T press mud per cycle Press mud required = (60 x 360)/3T = 7200T 10 acre of land = 850 x 10 T premud can be laid down in cycle = 8500T To lay down 7200 T press mud = 7200/850 = 8.5 Acre. 30% more land is required = 2.5 Total land = = 11 acre Land available 10 Acre Therefore RO shall be installed before composting.

161 Problem 2: Spent wash = 50 x 12 = 600 KL/day Spent Wash required for composting = 60 x 50 x12 = 36000KL Press mud required = 36000/3 = T 15 Acre land 850 x 15 = 12,750 T To lay down 12,750 T press = 12,750/850 = % More land = 4.23 Total land = However, press mud availability is less Press mud available for a cycle 5000x.04x60= 12000T Excess amount of spent wash shall be incinerated or fresh mud shall be collected.

162 Concentration followed by incineration (best practice) Method 1 Power generation - SW is concentrated up to per cent and fired in boiler, with or without subsidiary fuel Exhaust steam from power plant is used in distillery and concentration of SW though MEE (e.g of complete ZLD) Method 2 Possible to concentrate SW up to 40-50% and mix it with rice husk, bagasse etc. and dryed in a rotary dryer to about % solids and use it for power generation

163 Concentration & Burning of Spent-wash SPENTWASH 12 M3/ KL REBOILERS SPENTWASH BURNING M3/ KL PROCESS CONDENSATE 7-8 M3/ KL CONCENTRATE 2-3 M3/ KL EVAPORATOR CONCENTRATE CONDENSATE

164 Treatment, Recycle & Reuse A. Spent wash - Molasses Option II : Concentration & Incineration Route Spent Wash Evaporation (Concentration) Incineration Boiler % Recycle To Fermentation (Depends on Molasses Quality)

165 Concentration followed by incineration Advantages Spent wash is used as fuel, every kg of concentrated spent wash replaces nearly 0.33 kg of Indian coal Less land requirement Zero liquid discharge Independent from monsoon, statutory requirements, etc. Energy conservation - no separate boiler for steam generation, exhaust steam for power plant can be use in process and operating evaporator.

166 Concentration followed by incineration Standalone factory no other option Ash generated from the boiler has high potash content, which can be used in fields for improving soil conditions Promotes water conservation No requirement of storage lagoons and hence lesser chances of pollution

167 Concentration followed by incineration According to Mr. M. Prakash (V.P., EID Parry) Economically viable to generate power from Spent Wash if plant capacity >45 KLPD of alcohol production Capital cost is Rs. 2 crore per KL of alcohol O&M cost is Rs /liter alcohol. Payback period is 4.5 to 5 years

168 Case study - Sivaganga distillery Capacity 60 KLPD, Molasses based Cost of the Project Rs. 90 Crores Cost for incineration Rs. 38 crores Water requirement Total 853 m3/day, of total 380 m3/day is fresh water and 473 m3/day condensate and recycle water from evaporator Capacity of power plant 1.6 MWh Coal to spent wash ratio On weight basis (norms 30 : 70, but actual they are using 20:80) Ash from power plant Ash is rich in nutrient contains total potash >19% and water soluble potash >15% is transformed into granules and sold in the market

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170 View of MEE

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172 Cost economics s.no. Bio-methanization followed by Bio-composting 1 Steam No cost as requirement met from Biogas Steam Requires coal of 60 tons per Rs. 3.0 lacs per day (Rs 5 per ltr of alcohol) 2 Power Rs. 2.0 per ltr of Alcohol Rs.0.5 per ltr of alcohol 3 R & M Rs per ltr of alcohol R & M Rs 1.0 per ltr of alcohol 4 Income through Biocompost Rs 0.2 / ltr Income through potash ash Rs 1.5 / ltr 4 Investment Rs 25 crores Investment Rs 38 crores Concentration followed by incineration When compared to conventional distillery with bio methanation followed by biocomposting, the cost of production is higher by about Rs. 3 to 4 per ltr of alcohol with incineration system Centre for Science and Environment

173 What was the ISSUE after Spent Wash Incineration? Flyable Pollution Threat to Health & Environment Difficult to Dispose Additional Expenses on Disposal

174 Fly Ash as Waste

175 KASH specification The FCO specification for this fertilizer is as follows: Moisture % by weight, Max Total Nitrogen % by weight, Mini Water soluble phosphate (as P2O5) % by weight, Mini Water soluble potash (as K2O) % by weight, Mini Our Kash product specs Moisture % by weight, Max Total Nitrogen % by weight, Max Water soluble phosphate (as P2O5) % by weight, Max Water soluble potash (as K2O) % by weight, Min

176 Ash converted as Fertilizer As per FCO norms Product Specification: Brown to black Colour Round Granule 2-6 mm Size Moisture 4-5% Dispersible in Water Total Potash - >19% W.S. Potash - >15%

177 Concentration & biofertilizers Not economical to generate power, if plant capacity < 45 KLPD In such cases, viable option to achieve ZLD bio-methanation followed by concentration spent wash (RO/MEE up to 35 to 40%.) - further concentrated to 95% with the help of spray dryer s - use as fertilizers Cost of the fertilizer is approx. Rs.1500 per metric ton Example Ugar sugar works, Karnataka Fertilizer is also included under FCO (Fertilizer Control Order) act by Ministry of Agricultural & Co-operation

178 A. Treatment, Recycle & Reuse Thin Slops - Grain as feedstock Option II : EVAPORATION & CATTLEFEED Thin Slops Evaporation Syrup mixed with Wet Cake DWGS % Recycle To Liquefaction TECHNOLOGY & ADVANTAGES : % THIN SLOPS RECYCLE POSSIBLE TO LIQUEFACTION 1. COMPACT PLANT, HUGE ENERGY SAVINGS WITH INTEGRATED EVAPORATION WITH DISTILLATION PLANT 3. WET CAKE (FIBRES) SEPARATED EARLIER IN DECATATION IS ENRICHED WITH DISSOLVED PROTEINS (SYRUP) FROM EVAPORATION. HENCE VALUE ADDED CATTLE FEED

179 Case Study A. 100 KLPD Distillery complex Cane - Molasses as Feedstock Water Quality Requirement Without Treatment & Recycle (M3/day) Requirement With Treatment & Recycle (M3/day) Process Water Soft Water DM Water Total Consumption KL / KL Total Water Savings = 42 %

180 Case Study B. 100 KLPD Distillery complex Grain as Feedstock Water Quality Requirement Without Treatment & Recycle (M3/day) Requirement With Treatment & Recycle (M3/day) Process Water Soft Water DM Water Total Consumption KL/ KL Total Water savings = 51 %

181 Comparative Analysis of Technologies

182 Process Technology Land requirement (hectares/mld installed capacity) O&M cost (million/year/ MLD installed capacity) Energy requirement (KWh/ML treated) Capital cost (million /MLD capacity) Effluent Quality Distinct Advantage ASP 0.15 to 0.25 Rs 0.3 to to 225 Rs 2 to 4 BOD: mg/l. Suspended solids (SS):20-50 mg/l. The effluent obtained is colourless. Land requirement is very less and performance is not affected by normal variation in wastewater characteristic. Trickling Filter (TF) 0.25 to 0.65 Slightly lower than ASP 180 Relatively lower than ASP Comparable to ASP Rugged system with simple and silent operation Waste Stabilization Ponds (WSP) 0.8 to 2.3 Rs 0.06 to 0.1 Energy required for the operation of screen and grit chamber, negligible as compared to ASP Rs 1.5 to 4.5 BOD: mg/l. SS: mg/l. The colour of water is greenish. Very easy operation and maintenance Upflow Anaerobic Sludge Blanket (UASB) 0.2 to 0.3 Rs 0.08 to to 15 Rs 2.5 to 3.5 BOD: mg/l Can absorb hydraulic and organic shock loading. Sludge handling is minimal SS: mg/l

183 Rotating Biological Contractor (RBC) N.A N.A Very low as compared to ASP N.A Comparable to ASP Ease of installation and commissioning. Simple to operate and maintain Sequencing Batch Reactor (SBR) 0.1 to 0.15 Higher than ASP 150 to 200 Higher than ASP BOD<5 mg/l The process is time controlled and flexible. Fluidized Aerobic Bed (FAB) BOD<10 mg/l SS <20 mg/l No sludge recycling and monitoring of MLSS required. Submerged Aerobic Fixed Film (SAFF) reactor BOD<10 mg/l SS <20mg/L More compact than the conventional STP s Membrane Bioreactor (MBR) Rs 0.6 to to to 5. BOD<5 mg/l SS<10 mg/l Colourless water is obtained. Highest effluent quality for reuse and very high life cycle cost. TSS<10 mg/l