principal scientist

Dr. Girish R. Pophali Principal Scientist,

Wastewater Technology Division [email protected]

CSIR – National Environmental Engineering Research Institute, Nehru Marg Nagpur

Seminar

on

Waste Management in Indian Railways

June 6, 2016

"Challenges and Opportunities of Sewage Management for Indian

Railways"

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

CSIR NEERI, Nehru Marg Nagpur - 440 020

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


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


• Washing of railway tracks and platforms

• Washing of rail coaches and wagons

• Domestic sewage from railway colonies

Source of Wastewater 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)

Major Wastewater Pollutants in Railway Set-up


Need for Wastewater Treatment; Recycle & Reuse


Water Distribution Pattern in Urban Set-ups in India

• Recycled

water for

Flushing and

gardening can

cater nearly

50% of total

water supply.

• Thus, it would

offer huge

saving of fresh

water

resources

Challenges of Sewage Management in India

Major Issues

• Major Challenges

– Social

– Administrative

– Financial

– Technical

• Opportunities

– Recycle and reuse

– Resource conservation

– Energy generation


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

Opportunities • Pollution Prevention • Recycle • Reuse • Energy generation

Goals • Sustainable development • Environment conservation

Sewage Management Cycle


Wastewater from

Railway tracks &

Platforms


Wastewater Management for Indian

Railways; a new Perspective

Treatment & reuse

potential

Wastewater from

washing of Coaches &

Wagons

Treatment & reuse

potential

Domestic sewage from

railway colonies Treatment & reuse

potential

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, efficiency and ease of operation.

Major Challenges – Technical


Treatment Options

Sewage Treatment

Primary Secondary Tertiary Advanced / Polishing

treatment

Screen & grit removal

Oil & Grease Removal

Plain settling

Physico-chemical

precipitation

Aerobic

Activated sludge

process

Trickling filter

Membrane bioreactor

Fluidized aerobic

bioreactor

Sequential Batch

Reactor

Oxidation ponds

Aerobic lagoons

Anaerobic

Up-flow anaerobic

sludge blanket

Anaerobic Filter

Rotating biological

contactor

Stabilisation ponds

Nutrient (N, P) Removal

*Constructed

Wetlands

Nitrification-

denitrification

Membrane processes

Disinfection

Chlorination

Solar based

Ozonation

UV

* Can be used for Carbon

and Nutrient Removal

Dual media filters

Activated carbon

columns

Ultra-filtration

Nano filtration and

Reverse osmosis

Sludge Treatment

Gravity Thickening

Dewatering

Centrifuge

Rotating vaccum drum filter

Filter press & Sludge drying beds

Sludge Digestion

Anaerobic

Aerobic


• Selection Criteria for Technology options

Major Challenges – Technical

Economic Technical (Treatment Efficiency)

Administrative

Capital Costs BOD, COD, TSS removal, Emerging Pollutants

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


Sustainable Solutions; Conservation / Recycle/ Reuse

Or Influent*

Single-tank SBR

Membrane bioreactor

Treated Effluent

Treaed Effluent

Sludge

Sludge

Effluent

Effluent

Rejects

Permeate

Membrane Processes

Influent*: Obtained after screen;

grit; oil & grease and settleable

solids removal

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 CSIR NEERI, Nehru Marg Nagpur - 440 020

Energy through

bio-gas Influent*

Single-tank SBR

Membrane bioreactor

Treated Effluent

Treaed Effluent

Sludge

Sludge

Anaerobic Reactor

Effluent

Effluent

Or

Influent*: Obtained after screen; grit; oil & grease and settleable solids removal

Rejects

Permeate

Membrane Processes

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



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,

Influent*

Anaerobic

Filter Cascade

Aeration Subsurface

Engineered Wetland

Disinfection

Optional - Pressure

sand filter & Activated

carbon column

Energy through

Bio-gas

Influent*: Obtained after screen; grit; oil &

grease and settleable solids removal

Reuse in land

application



Schematics of Techno-economic Treatment System for Domestic Sewage Management (100 m3/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 – 1st & 2nd Stage, P – Pumps

Pictures of OFAJ Plant; 100 m3/d capacity


Pictures of OFAJ Plant, Sludge Management & Greenbelt Development


Characteristics range for sewage and Standards

pH: 6.8 – 7.0 (5.5 – 9.0) COD: 200 – 350 [<20] (250) mg/L BOD: 100 – 150 [< 5] (30) mg/L TSS: 200 – 300 [<10] (100) mg/L TKN: 20 – 40 [< 10 (100) mg/L TP: 2 – 6 [< 1] (5) mg/L TDS: 300 – 500 (2100) mg/L Oil & Grease: 25 – 40 (<5) (10) mg/L Values in [ ] indicate achievable effluent quality

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 m3/d

• Takalghat Hingna for a housing complex; 30 m3/d

• MOIL Gumgaon; 200 m3/d and

• Under implementation in Villages

Patansawangi ; 200 m3/d

Navegaon Sadhu; 50 m3/d

Fetari; 300 m3/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


Conventional Vs. ENSeTS; Flow Capacity 1000 m3/d

Parameters

Conventional STP

(ASP)

ENSeTS

Approx. Capital Cost Rs 1.3 – 1.5 Cr Rs 1.2 – 1.4 Cr

Approx. O & M Cost Rs. 25 – 30 / m3 Rs. 10 – 15/ m3

Approx. Land Area 1.0 – 1.2 m2/ m3 1.5 – 1.8 m2/m3

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 Low, due to life of

equipment

High, no major equipment

are involved

Further treatment Yes, nutrient removal

and disinfection

Disinfection


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.


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

Way Forward and Future Trends


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


principal scientist

Documents