Dr. Girish R. Pophali Principal Scientist, Wastewater Technology Division

Transcription

1 Seminar on Waste Management in Indian Railways June 6, 2016 "Challenges and Opportunities of Sewage Management for Indian Railways" Dr. Girish R. Pophali Principal Scientist, Wastewater Technology Division CSIR National Environmental Engineering Research Institute, Nehru Marg Nagpur

2 Major Activities Basic Engineering Package for Wastewater (ETPs & CETPs) Renovation & Up-gradation of Effluent Treatment Plants Infusing Modern Process and Treatment Technologies. Technologies to Facilitate Compliance with Discharge Norms Zero-discharge Based Wastewater Treatment Technologies for Various Industries Cost apportionment for CETPs Recycle & Reuse and Resource Recovery Domestic and Laboratory wastewater treatment Pilot scale sewage treatment Grey water recycle and reuse

3 Spin off Areas Scale-up of Wastewater Treatment Technologies Modeling of Wastewater Treatment Processes Removal of Dissolved Solids from wastewater Advanced Methods for Removal of Nutrients from Wastewater Monitoring & Removal of Volatile Organic Compounds Natural Purification Systems for Wastewater Treatment Land Application of Treated Wastewater Adsorbents for Heavy Metals Removal Disinfection of Water, Sewage & Treated Effluents

4 Major Milestones Turnkey Projects on CETPs at Pali & Balotra R & D studies on Textile, SS Rolling Mills, Pharmaceutical, Tanneries, Chemical, Distilleries, RO & NF rejects, Rice Mills etc. Development of techno-economical treatment processes for domestic and industrial wastewaters Development of Novel Circular Secondary Clarifier Societal missions and technical support to Hon ble High Courts and Supreme Court

5 Source of Wastewater in Railway Set-up Washing of railway tracks and platforms Washing of rail coaches and wagons Domestic sewage from railway colonies

6 Major Wastewater Pollutants in Railway Set-up ph Suspended solids (SS) Oil & grease Bio-degradable organic matter (BOD) Nutrients (nitrogen and phosphorous) Total dissolved solids (TDS) Pathogens (Harmful bacteria)

7 Need for Wastewater Treatment; Recycle & Reuse Recycled water for Flushing and gardening can cater nearly 50% of total water supply. Thus, it would offer huge saving of fresh water resources Water Distribution Pattern in Urban Set-ups in India

8 Challenges of Sewage Management in India Major Issues Major Challenges Social Administrative Financial Technical Opportunities Recycle and reuse Resource conservation Energy generation

9 Wastewater Management; a new Perspective It is essential to look at Sewage Management as an Investment rather than Expenditure Challenges of Sewage Management Social Administrative Financial Technical Sewage Management Cycle Opportunities Pollution Prevention Recycle Reuse Energy generation Goals Sustainable development Environment conservation

10 Wastewater Management for Indian Railways; a new Perspective Wastewater from Railway tracks & Platforms Treatment & reuse potential Wastewater from washing of Coaches & Wagons Treatment & reuse potential Domestic sewage from railway colonies Treatment & reuse potential

11 Major Challenges Technical Technology options for sewage treatment The Problem A large number of technology options exist for Sewage treatment. These options differ from each other in some way or the other The sole objective should be to get maximum benefits with minimum costs. However, this is possible only after assessing primary data of effluent treatment alternatives. The assessment of treatment options involves evaluation of various factors such as economy, CSIR NEERI, efficiency Nehru Marg Nagpur and ease 020 of operation.

12 Treatment Options Sewage Treatment Primary Secondary Tertiary Screen & grit removal Oil & Grease Removal Plain settling Physico-chemical precipitation Aerobic Nutrient (N, P) Removal Activated sludge process *Constructed Wetlands Trickling filter Nitrificationdenitrification Membrane bioreactor Fluidized aerobic Membrane processes bioreactor Disinfection Sequential Batch Chlorination Reactor Solar based Oxidation ponds Ozonation Aerobic lagoons UV Anaerobic Up-flow anaerobic sludge blanket * Can be used for Carbon and Nutrient Removal Anaerobic Filter Rotating biological contactor Stabilisation ponds Sludge Treatment Advanced / Polishing treatment Dual media filters Activated carbon columns Ultra-filtration Nano filtration and Reverse osmosis Gravity Thickening Dewatering Centrifuge Rotating vaccum drum filter Filter press & Sludge drying beds Sludge Digestion Anaerobic Aerobic

13 Major Challenges Technical Selection Criteria for Technology options Economic Capital Costs Technical (Treatment Efficiency) BOD, COD, TSS removal, Emerging Pollutants Administrative Ease of operation O & M Costs Nutrient & Coliforms Removal Designated end use of treated effluent Land Area Treatment time, Sludge generation & Handling, Operating flow capacity - - Permeate recovery, TDS removal, Rejects generation - Techno-economical and environmentally sustainable treatment option should be adopted considering all above factors

14 Sustainable Solutions; Conservation / Recycle/ Reuse Influent* Single-tank SBR Treated Effluent Or Sludge Rejects Permeate Membrane bioreactor Treaed Effluent Membrane Processes Influent*: Obtained after screen; grit; oil & grease and settleable solids removal Sludge Sewage Treatment Option with Low Foot Print Area and Reuse of Treated Effluent for Urban Set-up Advantages: Low foot print area, High treatment efficiency, High effluent quality Disadvantages: High capital and O&M costs, Requires skilled manpower

15 Sustainable Solutions; Conservation / Recycle/ Reuse Single-tank SBR Treated Effluent Influent* Energy through bio-gas Or Sludge Rejects Permeate Anaerobic Reactor Membrane bioreactor Treaed Effluent Membrane Processes Sludge Influent*: Obtained after screen; grit; oil & grease and settleable solids removal Wastewater Treatment Option with Low Foot Print Area, Energy Generation and Reuse of Treated Effluent for Urban Set-up Advantages: Medium foot print area, High treatment efficiency, High effluent quality and energy recovery Disadvantages: High capital and O&M costs, Requires skilled manpower

16 Sustainable Solutions; Conservation / Recycle/ Reuse Energy through Bio-gas Influent* Anaerobic Filter Cascade Aeration Subsurface Engineered Wetland Influent*: Obtained after screen; grit; oil & grease and settleable solids removal Optional - Pressure sand filter & Activated carbon column Disinfection Reuse in land application Sewage Treatment Option with Low Capital, O&M costs; Energy Generation and Reuse of Treated Effluent for Small Towns Advantages: Highly Techno-economical, Low capital and O&M costs, Does not require skilled manpower, High treatment efficiency and energy recovery Disadvantages: Large foot-print Area is required,

17 Schematics of Techno-economic Treatment System for Domestic Sewage Management (100 m 3 /day) OFAJ Site To short rotation plantation 1) Screen chamber 2) Oil & Grease Trap 3) Raw Sewage Sump 4) Primary Clarifier 5) Upflow attached growth anaerobic filter 6) Bio-gas vent and collection 7) Subsurface flow constructed wetland 8) Holding Tank 9) Cascade aeration 10) Effluent collection tank 11) Dual media (pressure) filters 12) Activated carbon columns 13) On Line chlorine disinfection 14) Treated effluent collection tank 15) Pumping & Piping for treated effluent reuse 16) Sludge Drying Reed Beds 17) French Reed Beds 1 st & 2 nd Stage, P Pumps

18 Pictures of OFAJ Plant; 100 m 3 /d capacity

19 Pictures of OFAJ Plant, Sludge Management & Greenbelt Development Characteristics range for sewage and Standards ph: ( ) COD: [<20] (250) mg/l BOD: [< 5] (30) mg/l TSS: [<10] (100) mg/l TKN: [< 10 (100) mg/l TP: 2 6 [< 1] (5) mg/l TDS: (2100) mg/l Oil & Grease: (<5) (10) mg/l Values in [ ] indicate achievable effluent quality

20 Development of Engineered Natural Sewage Treatment System (ENSeTS) Salient Features of ENSeTS Meets stringent Discharge Norms of Regulatory Bodies Development of Technical specifications Know-how of ENSeTS is ready for licensing Implementation of ENSeTS in District Nagpur at Ordnance Factory Ambajhari Nagpur; 100 m 3 /d Takalghat Hingna for a housing complex; 30 m 3 /d MOIL Gumgaon; 200 m 3 /d and Under implementation in Villages Patansawangi ; 200 m 3 /d Navegaon Sadhu; 50 m 3 /d Fetari; 300 m 3 /d Advantages of ENSeTS Low operation & maintenance cost Low energy intensive Does not require skilled manpower No fly & odour nuisance and aesthetically acceptable Robust and less prone to process upsets Highly sustainable under Indian conditions

21 Conventional Vs. ENSeTS; Flow Capacity 1000 m 3 /d Parameters Conventional STP ENSeTS (ASP) Approx. Capital Cost Rs Cr Rs Cr Approx. O & M Cost Rs / m 3 Rs / m 3 Approx. Land Area m 2 / m m 2 /m 3 Skilled Manpower required Yes No Resource recovery No Yes, biogas generation Treatment efficiency Good Very Good Nutrient removal No Yes Aesthetics acceptability Low High Ease operation Low High Electro-mechanical equipment Yes Very less Sustainability Further treatment Low, due to life of equipment Yes, nutrient removal and disinfection High, no major equipment are involved Disinfection

22 Advantages of Natural Treatment Systems Highly Techno-economical and environmentally sustainable, Requires Low capital and O&M costs, Does not require skilled manpower, High treatment efficiency with removal of Primary, Secondary and Tertiary Pollutants Sludge handling & management is done through natural systems Energy recovery through anaerobic systems The treated effluent can be used for non-potable purpose including gardening, floor washing, flushing and green belt development.

23 Way Forward and Future Trends Way Forward Selection & Application of well proven treatment process for domestic and industrial wastewaters; e.g. Fluidised Aerobic Bioreactors (FAB) have yet to be successfully implemented in treating sewage. Choice of process between Suspended Vs Attached Growth; e.g. UASB s and SBR s limitations as reported in CPHEEO Manual (2013) Selection of treatment process between Chemical and Biological; as far as possible chemical treatment should be avoided for biodegradable wastes Use of Physical Processes such as Equalisation, Dissolved Air Flotation and Settling are highly desirable as pre-treatment since they substantially reduce the pollution load on secondary and tertiary treatment systems Future Trends Identification, treatment and removal of emerging pollutants in Sewage Targeting Recycle and Reuse of treated effluent instead of meeting Environmental Discharge Norms alone Adopting a combination of natural and advanced technologies to ensure techno-economic and sustainable solutions

24 Conclusions The challenges of sewage management give us an opportunity to conserve the environment and serve the society at large Indian Railways can target to have an ISO certification for Sewage and grey-water management It is essential to look into the social, administrative, financial and technical aspects to make Sewage Management as an Investment rather than Expenditure

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