DECENTRALIZED WASTEWATER TREATMENT SYSTEMS
Dr. SHIRISH NAIK, Chairman and Managing Director,Naik Enviro, Mumbai, IndiaFormer Faculty, Indian Institute of Technology , Mumbai , Indiawww.naikenviro.com
Sewage Treatment Facilities & disposal system
Pumping stations
Sewer network
COMPONENTS OF WASTEWATER MANAGEMENT SYSTEMS
COST DETERMINANTS
• EXCAVATION , BACKFILL & ROAD REINSTATEMENT• PIPES• BEDDING• MANHOLES• PUMPING STATIONS• SEWAGE TREATMENT PLANTS• TREATED SEWAGE DISPOSAL/ REUSE SYSTEM
NAIKENVIRO THE HEART-N-SCIENCE OF ENVIRONMENTAL ENGINEERING
DECENTRALIZED CONFIGURATIONS FOR COST EFFECTIVENESS
Drastic reduction in pipe sizes
Reduction in manhole depths
Reduction in depths and excavations
NAIKENVIRO THE HEART-N-SCIENCE OF ENVIRONMENTAL ENGINEERING
NAIK ENVIRO’S APPROACH– DECENTRALIZED CONFIGURATIONS
sources
treatmentReuse/recyclelocations
CENTRALIZEDDE-CENTRALIZED
DRASTIC REDUCTION IN CAPEX AND OPEX
CAPEX/OPEX
KEY DECISIONS
KEY DECISIONS
NUMBER OF ZONES &
DEMARKATION
PHASED EXPANSION
TREATMENT TECHNOLOGIES
REUSE/ RECYCLE OPTIOSN
NUMBER OF ZONES AND DEMARKATION
ZONING CONFIGURATION
DECISION
TOPOGRAPHY & POPULATION
DENSITY PROFILE
SENSITIVE ZONES, SOIL PARAMETERS
ADMINISTRATIVE BOUNDARIES &
AVAILABLE SITES
DIVIDERS LIKE
RAILWAY LINES,
RIVERS ETC
PHASED EXPANSION
ZONING WILL DEPEND ON PHYSICAL FEATURESLIKE RIVERS FLOWING THROUGH CITY OR RAILWAY LINES
DIVIDING THE CITY INTO ZONES
STP SITE SELECTION CRITERIA• Space availability• Land Acquisition constraints • Land cost• Potential future uses of candidate sites• Growth dynamics• Sensitive receptors• Soil mechanics • Topography• Treated sewage reuse zones• Feasibility of laying sewer lines upto STP• Invert depths of sewers at STP site
CANDIDATE SITES FOR STPS• Sewage Pumping station premises
• Old STP premises
• Parks & Playgrounds (underground STPs)
• Reclaimed Landfill sites
• Span across Natural Drains
STP TECHNOLOGY SELECTION CRITERIA• Foot print needed• Environmental Impacts• Sound• Odour & aerosol contamination• Land value impacts • Complexity and extent of civil works• Economic decision variables• CAPEX• OPEX• Present Worth• Technology Track Record, especially low flow Handling capability
PRESENT WORTH ANALYSIS
• F= (1+(1+I)^n/((I*(1+I)^n
Capital costO&M cost
Convert O&M costTo present worth
Present worth Of capital cost
Pres
ent w
orth
Time horizon
TRIAXIAL TRADE-OFF
Optimal Solution
Phased expansion
DecentralizationSystem Synthesis and process optimization
HEURISTIC CONSIDERATIONS IN PHASED EXPANSION OPTIMIZATION
200 TIME HORIZON 0 TIME HORIZON 20
EXCESS CAPACITIESEXCESS CAPACITIES
EXCESS (IDLE) CAPACITIES REDUCE COST EFFECTIVENESS
ECONOMY OF SCALE CONCEPTC
OST
PER
UN
IT O
F C
APAC
ITY
CAPACITYCO
ST P
ER U
NIT
OF
CAPA
CITY
CAPACITY
WEAK ECONOMY OF SCALE
INDICATES PREFERENCE OF MODULAR EXPANSION
STRONG ECONOMY OF SCALE
INDICATES PREFERENCE OF LONG TERM DESIGN HORIZON
ALGORITHM FORHEURISTIC OPTIMIZATION OF DECENTRALIZED WASTEWATER MANAGEMENT
• DATA COMPILATION• Road Map of city with contours, land use pattern, physical features etc
• Population and population density overlay on map – present and 5 years time spans till say 20years
• Show per capita water use and sewage generation on plan
• Show treated water reuse/ recyle zones and demands on plan
• Show existing sewerage system, pumping stations and STPs on plan
• Show candidate STP and pumping station sites with plot areas and tabulate soli data
• Show sensitive zones
• Show traffic density on road network and alternative routes
ALGORITHM FORHEURISTIC OPTIMIZATION OF DECENTRALIZED WASTEWATER MANAGEMENT
• DATA COMPILATION
• Tabulate cost data for system components and develop rate analysis chart, example..
• a) Cost per m of sewer line v/s dia and depth (all inclusive)
• b) Cost of manholes v/d depth and size
• c) Cost of u/g tanks v/s capacity and depth below GL
• d) Cost of pumping machinery v/s discharge and head
• e) Cost of substations v/s KVA
• f) Cost of various technologies-- v/s design flow for various use options
ALGORITHM FORHEURISTIC OPTIMIZATION OF DECENTRALIZED WASTEWATER MANAGEMENT
• DATA COMPILATION
• g) Cost of Power per Kwhr
• h) Manpower costs for various technologies v/s capacity
• i) Maintenance costs for various technologies v/s capacity and equipment age
• j) Compile land costs at pumping station and STP sites
ALGORITHM FOR HEURISTIC OPTIMIZATION OF DECENTRALIZED WASTEWATER MANAGEMENT
• Mark candidate STP locations and demarkate zones considering cotours, roads, sensitive zones, population densities etc
• Mark main and sub main sewer networks terminating at STPs and decide on number of zones and their demarcation. This is the first option. Take the maximum number of zones you would like to consider.
• Mark and compute drainage areas and multiply these by population densities applicable and per capita sewage generation. Use CPHEEO criteria to compute peak flows. Insert the peak flow numbers on the networks
• Input the data for various zones into to a sewerage design software or carry out the design using an excel template
ALGORITHM FOR HEURISTIC OPTIMIZATION OF DECENTRALIZED WASTEWATER MANAGEMENT
• Plots invert level profiles on road map and decide on intermediate pumping stations … compute CAPEX and OPEX of sewerage system
• Decide on time horizon for each zone based on flow estimates over 5 year intervals up to 20 years
• Compute space requirement for pumping stations and STPSs for the ultimate stage. Check adequacy of space and find options. Make note of space inadequacies for next iteration.
• Compute CAPEX including land costs and OPEX of zone STPs for selected technologies
• Compute overall CAPEX, OPEX and present worth of the overall system.
• Now you are ready for the next iteration in which you may merge some zones and repeat the exercise.
NETWORKING & AUTOMATION OF DECENTRALIZED STPS
• Control through SCADA (Supervisory Control and Data Acquisition) Alerts on mobile phones of control team.
• Central control hub with mobile squad
• Visual observation and control through cameras, DVDs and desktops
• Complete automation through Programmable Logic Controls (PLCs)
NAIKENVIRO The Heart-N-Science of Environmental Engineering
Raw sewage tank
Rotating Media Bio Reactors
Dual Media filters
Settlement tankSludge DewateringSystems
Raw sewage Pumps
9MLD COMPACT STP AT WADALA TRUCK TERMINUS
RMBR- 1,2,3
SETTLING TANK- 1,2,3
FILTERS
TREATED WATER TANKS
RAW SEWAGE
TANK
3-D DRAWING OF 1.5 MLD STP
1.5 MLD NAIK ENVIRO SCADA CONTROLLED COMPACT SEWAGE TREATMENT PLANT– 3D MODEL
PROCESS FLOW DIAGRAMRaw waste water pumpScreen
RMBR
Flocculation Channel
Settling Tank
Filter Feed TankPressure Sand Filter
Activated Carbon Filter
Meters:1] Flow meter2] pH meter3] Temperature meter4] DO meter
Treated Water Tank
Ozone Dosing System
Sludge Dewatering System
Backwash/Rinse
Sludge
Treated Water Tank
NAIKENVIRO
SCADA •The operating system at site is SCADA, which stands for supervisory control and data acquisition. It is an industrial control system where a computer system monitors and controls the ongoing operation/process.•The software gives various information's like details of pump operation, breakdown details, energy consumption, treated water quality parameters, historical trends etc.
Main Screen NAIKENVIRO
NAIKENVIRO The Heart-N-Science of Environmental Engineering
DECENTRALIZED STP FOR MUNICIPAL CORPORATION OF MUMBAI 1 MLDAT BANDRA, MUMBAI SEWAGE PUMPING STATION
NAIKENVIRO The Heart-N-Science of Environmental Engineering
DECENTRALIZED STP BASED ON ROTATNG MEDIA BIO REACTOR TECHNOLOGY FOR
MUNICIPAL CORPORATION OF MUMBAI 1 MLDAT BANDRA, MUMBAI SEWAGE PUMPING
STATION– ELEVATION VIEW