International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 12 Issue: 05 | May 2025 www.irjet.net p-ISSN: 2395-0072
Design of Sewage Treatment Plant of 50 KLPD to Serve 300 Residents of Sarita Vihar Staff Quarters of DMRC
Suresh Chandra Pandey1 , Himanshu2
1Student of Bachelor of Technology in Civil Engineering, Lingaya’s Vidyapeeth, Faridabad, India
2Student of Bachelor of Technology in Civil Engineering, Lingaya’s Vidyapeeth, Faridabad, India
Abstract -This paper outlines the design of a 50 KiloLiters Per Day (KLPD) Sewage Treatment Plant (STP) for the Sarita Vihar Staff Quarters of Delhi Metro Rail Corporation (DMRC). The plant aims to sustainably manage domestic sewage from 300 residents, ensuring compliance with environmental regulations. The design employs a multi-stage process including screening, grit removal, primary sedimentation, activated sludge treatment, secondary clarification, sludge digestion, and disinfection.Materialselection,hydrauliccalculations,and adherence to IS codes are emphasized. The treated effluent meets CPCB norms for exercise in gardening and flushing. The paper provides detailed design parameters, construction methodology, and cost analysis, pressing the factory’spartinpromotingindirectwaterfrugality.
Key Words: Sewage Treatment Plant (STP), 50 KLPD, DMRC, Activated Sludge Process, CPCB Standards, Sludge Digestion.
1. INTRODUCTION
UrbanizationinDelhihasboostedpressureonwastewater operation systems. The Sarita Vihar Staff Quarters, housing 300 DMRC employees, requires a decentralized STPtomitigateenvironmentalpollutionandenablewater reuse. Conventional centralized systems are often inefficient for small communities, necessitating compact, cost-effective solutions. This paper details the design of a 50 KLPD STP using biological treatment processes, aligning with IS codes and sustainability goals.Sludge Digestion.
1.1Scope of The Project
Theprimaryscopeofthisstudyis:
1. To design a 50 KLPD (Kilo-Liters Per Day) sewage treatment plant for the Sarita Vihar DMRC staff quarters, ensuring compliance with CentralPollutionControlBoard(CPCB)standards.
2. To adopt an efficient and cost-effective treatment process that minimizes energy consumption while maximizing treated water quality.
3. To ensure sustainable sludge management by incorporating anaerobic digestion and sludge dryingbedsforsafedisposalorreuse.
4. To facilitate water recycling by producing treated effluent suitable for non-potable applications,reducingfreshwaterdemand.
2.MATERIAL USED
2.1 Reinforced Cement Concrete (RCC) Structures
Concrete Grade: M25 (as per IS 456:2000) for tanks,foundations,andstructuralelements.
Reinforcement Steel: Fe 500D grade (as per IS 1786:2008)forhightensilestrength.
Waterproofing: Bituminous coating and epoxy liningtopreventleakage(asper IS 2645:1975).
2.2 Masonry Works
Bricks: First-class burnt clay bricks (as per IS 1077:1992) for boundary walls and ancillary structures.
Mortar: Cement-sand mortar (1:4 ratio) for brickworkandplastering.
2.3 Piping and Conduits
Sewer Pipes:
o HDPE pipes (as per IS 4984:2020) for external drainage due to corrosion resistance.
2.4 Chemical and Disinfection Materials
2.4.1 Coagulants and Flocculants
Alum (Aluminium Sulfate): Used in primary treatmentforsuspendedsolidsremoval.
Polyelectrolyte: Anionic polymer for sludge dewatering.
International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 12 Issue: 05 | May 2025 www.irjet.net p-ISSN: 2395-0072
2.4.2 Disinfection Agents
Sodium Hypochlorite (NaOCl): 5-10 mg/L dosage for final effluent disinfection (as per IS 1061:2018).
Chlorine Contact Tank: FRP (Fiber Reinforced Plastic)constructionforcorrosionresistance.
3. PROJECT DETAILS
3.1 Population and Sewage Generation Estimation
3.1.1 Population Served
Total Residents:300(DMRCstaffandfamilies).
Assumed Water Consumption: 150 liters per capita per day (LPCD) as per IS 1172:1993 (Indian Standard for Basic Requirements for Water Supply, Drainage, and Sanitation).
3.1.2 Sewage Generation Calculation
Total Water Consumption = 300 persons × 150 LPCD= 45,000 liters/day (45 KLD)
Sewage Generation (assuming 80% return flow) =45KLD×0.8= 36 KLD
Design Capacity (with 20% safety margin for peakflow)= 50 KLPD
3.2 Influent Sewage Characteristics
Parameter
BiochemicalOxygen Demand(BOD)
3.3 Site-Specific Considerations
3.3.1 Land Availability
Total Area Required: ~200m²(including buffer zone).
Layout Plan:
o Compact Design: Sequential arrangement of units to minimize footprint.
o Underground vs. Aboveground: Partially underground for aesthetic and space-savingbenefits.
3.3.2 Hydraulic Loading Conditions
Peak Flow Factor: 1.5 (as per IS 2470:1985 for small-scaleSTPs).
Design Flow:50KLD(average), 75 KLD (peak).
3.3.3 Climatic Factors
Temperature: Delhi’s average (15°C–40°C) affectsmicrobialactivityinbiologicaltreatment.
Monsoon Impact: Increased inflow dilution; grit chambersdesignedforhigherflowrates.
3.4 Treatment Objectives and Effluent Standards
3.4.1 Treated Water Quality Targets
350 ≤350 IS3025(Part 44):1993 ChemicalOxygen Demand(COD)
600 ≤600 APHA5220D
TotalSuspended Solids(TSS) 300400 ≤400 IS3025(Part 17):1984 pH 6.5–8.5
IS3025(Part 11):1983
TotalNitrogen(as N)
≤50 IS3025(Part 34):1988
3.4.2 Reuse Applications
Gardening: Treated water meets IS 10500:2012 (ClassA)forirrigation.
Flushing/Toilet Use: Complies with CPB 2015 normsfornon-potablereuse.
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Volume: 12 Issue: 05 | May 2025 www.irjet.net
3.5 Process Flow Diagram (PFD) and Unit Operations
3.5.1 Treatment Stages
1. Preliminary Treatment
o Coarse Screening (20 mm) → Fine Screening(5mm)→GritChamber.
2. Primary Treatment
o Primary Sedimentation Tank (Detention Time:2hrs).
3. Secondary Treatment
o Activated Sludge Process (ASP) → SecondaryClarifier.
4. Tertiary Treatment (Optional)
o Sand Filtration → Chlorination (NaOCl dosing).
5. Sludge Management
o Anaerobic Digester → Sludge Drying Beds.
3.5.2 Key Design
for Each Unit
: Solar-powered aerators forsustainability.
3.7 Summary of Project Specifications Aspect Specification
Design Capacity
KLPD(75KLPDpeak)
Treatment Process ASP+Chlorination Land Requirement
Effluent Standards CPCBReuseNorms
Sludge Handling DryingBeds+Composting
4. ANALYSIS AND DESIGN
4.1 Design Basis and Assumptions
3.6 Power and Utility Requirements
Flow(Qpeak)
(Part 1):1985
(Part 1):1985
KLD(75 m³/day) -
IS12288:1987
International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 12 Issue: 05 | May 2025 www.irjet.net p-ISSN: 2395-0072
4.2 Design of Preliminary Treatment Units
4.2.1 Screening Unit
Function: Remove large debris (plastics, rags, etc.).
Design:
o Coarse Screen (20 mm spacing)
Width=0.6m,Depth=0.8m
Velocity = 0.6 m/sec (to prevent gritdeposition)
o Fine Screen (5 mm spacing)
4.2.2 Grit Chamber
Mechanicallycleaned(SS304)
Slope=45°forself-cleaning
Type:AeratedGritChamber(DetentionTime=2–3min)
Design Calculations:
o Volume (V) = Qpeak × Detention Time = 75m³/day×(3/1440)days= 0.156 m³
o Dimensions:L ×W ×D=1.5m×0.5m× 0.5m
o AirSupply=0.3m³/minpermeterlength
4.3 Design of Primary Treatment (Primary Sedimentation Tank)
4.3.1 Tank Dimensions
Surface Loading Rate = 30 m³/m²/day (IS 3406:1987)
Required Surface Area (A) = Qavg / Loading Rate=50/30= 1.67 m²
Tank Diameter (Circular Tank) = √(4 × A/π) = 1.46 m → Take 2 m
Side Water Depth (SWD) =2.5m
Detention Time =Volume/Qavg=(π×1²×2.5) /50≈ 4 hours
4.3.2 Sludge Collection
Sludge Quantity =0.8kgTSS/m³sewage
Daily Sludge Production = 50 m³/day × 0.8 kg/m³= 40 kg/day
4.4 Design of Secondary Treatment (Activated Sludge Process)
4.4.1 Aeration Tank Design
BOD Load = 50 m³/day × 300 mg/L = 15 kg BOD/day
F/M Ratio =0.3(Assumedforextendedaeration)
MLSS Required = BOD Load / (F/M) = 15 / 0.3 = 50 kg
Volume of Aeration Tank (V) = MLSS / MLSS Concentration=50/3= 16.67 m³
Dimensions: L × W × D = 4 m × 2 m × 2.1 m (EffectiveDepth=2m+Freeboard0.1m)
4.4.2 Oxygen Requirement
Theoretical O₂ Demand =1.5kgO₂/kgBOD
Total O₂ Required =15kgBOD/day×1.5= 22.5 kg O₂/day
Aeration System: Fine Bubble Diffusers (O₂ TransferEfficiency=8%)
Air Flow Rate = (22.5 / 0.08) / (24 × 60) = 0.2 m³/min
4.4.3 Secondary Clarifier
Overflow Rate =20m³/m²/day(IS12288:1987)
Surface Area Required =Qavg/OverflowRate= 50/20= 2.5 m²
Diameter =√(4×2.5/π)= 1.78 m → Adopt 2 m
Depth =3m(IncludingSludgeZone)
4.5 Sludge Handling and Disposal
4.5.1 Sludge Digestion Tank
Sludge Quantity = 40 kg/day (Primary) + 20 kg/day(Secondary)= 60 kg/day
Volatile Solids (VS) = 70% of TSS → 42 kg VS/day
Digester Volume = VS Loading Rate = 1 kg VS/m³/day
International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 12 Issue: 05 | May 2025 www.irjet.net p-ISSN: 2395-0072
Required Volume =42/1= 42 m³
Dimensions:4m(Dia)×3.5m(Height)
4.5.2 Sludge Drying Beds
Sludge Loading Rate =100kg/m²/year
Bed Area Required = (60 kg/day × 365) / 100 = 219 m²
Number of Beds:4beds(each7m×8m)
4.6 Disinfection Unit (Chlorination)
Chlorine Dose =5mg/L
Daily Chlorine Requirement = 50 m³/day × 5
g/m³= 250 g/day
Contact Time =30min
Contact Tank Volume =Qpeak×t=(75m³/day)
×(30/1440)= 1.56 m³
4.7 Summary of Design Parameters
5.1.2 Graphical Representation of Removal Efficiency
Figure 1: BOD and COD Removal Efficiency
5. Results
5.1 Effluent Quality After Treatment
5.1.1 Comparison of Influent vs. Effluent Parameters
Key Observations:
BOD removal >95% indicateseffectivebiological treatment.
TSS removal >94% due to efficient sedimentationandfiltration.
Disinfection (Chlorination) ensures fecal coliformsarewithinreuselimits.
BOD
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5.2 Sludge Generation and Management
5.2.1 Sludge Quantities Sludge
5.2.2 Sludge Drying Bed Performance
Drying Time:7–10days(Delhiclimate).
Final Sludge Cake: 30% solids → Safe for composting.
5.3 Energy Consumption Analysis
5.3.1 Energy Efficiency Measures
Solar-powered aerators can reduce grid dependencyby 30%
VFD-controlled pumps optimize flow rates, saving 15% energy
5.4 Cost Analysis
5.4.1 Capital Cost Breakdown
5.4.2 Operational Cost (Monthly)
5.4.3 Payback Period (If Reused for Gardening/Flushing)
Water Savings: 50 KL/day × ₹20/KL = ₹1,000/day (₹30,000/month)
Payback Period =CapitalCost/(Savings–OPEX) ≈ 8–10 years
5.5 Compliance with Regulatory Standards
CPCB Reuse Standards:Fullycompliantfor nonpotable applications (gardening,flushing).
IS 3307:2017 (Sludge Disposal): Sludge meets ClassBcompoststandards.
5.6 Summary of Key Results Aspect Outcome
Effluent Quality BOD≤10mg/L,TSS≤20mg/L
Sludge Handling 60kg/day→Composted/Dried
International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 12 Issue: 05 | May 2025 www.irjet.net p-ISSN: 2395-0072
Aspect Outcome
Energy Use
116.4kWh/day(OptimizablewithSolar)
Cost Efficiency ₹2.05LCapEx,₹48K/monthOpEx
6. Construction Methodology
1. Site Preparation: Leveling and soil testing (IS 1498:1970).
2. Excavation:Depthof4mfortanks.
3. Concrete Work: M25 grade concrete (IS 456:2000).
4. Installation: Sequential assembly of screens, pumps,andblowers.
5. Testing:Leakagechecksandtrialruns.
7. References
1. IS456:2000–ConcreteDesign.
2. CPCB(2015). Effluent Discharge Standards
3. Metcalf & Eddy (2014). Wastewater Engineering: Treatment and Reuse.