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06 - P&ID Reference Documentation

Process & Instrumentation Diagram reference for the Water Treatment Plant CAD model

Overview​

This document provides the complete P&ID (Piping and Instrumentation Diagram) reference for the water treatment plant CAD integration. The diagram follows ISA-5.1 instrumentation symbols and standard equipment tagging conventions.

Complete Process & Instrumentation Diagram Reference​

Equipment Schedule​

Process Vessels & Tanks​

Tag IDEquipment NameTypeCapacity/SizeMaterial
SCR-01Bar ScreenMechanical Screen50mm spacingSS 316
GR-01Grit ChamberAerated Grit15 m³Concrete
CL-01Primary ClarifierCircular500 m³, Ø12mConcrete
AER-01Aeration TankRectangular1000 m³Concrete
SC-01Secondary ClarifierCircular600 m³, Ø14mConcrete
DIS-01Contact TankSerpentine100 m³Concrete
CH-TK-01Chemical Storage TankVertical5 m³HDPE

Rotating Equipment​

Tag IDEquipment NameTypeCapacityMotor
P-201RAS PumpCentrifugal200 m³/hr @ 10m15 kW
P-301Dosing PumpDiaphragm0-100 L/hr0.5 kW
BL-201Aeration BlowerRotary Lobe500 Nm³/hr @ 0.5 bar30 kW

Valves​

Tag IDValve TypeSizeFunction
FV-201Control ValveDN150Aeration rate control
HV-101Gate ValveDN300Inlet isolation
HV-106Gate ValveDN250Outlet isolation

Instrumentation Schedule​

Flow Instruments​

Tag IDDescriptionRangeOutputLocation
FIT-101Influent Flow0-2000 m³/hr4-20 mARaw Sewage Line
FIT-103Primary Effluent Flow0-2000 m³/hr4-20 mAAfter Primary
FIT-105Final Effluent Flow0-2000 m³/hr4-20 mAAfter Disinfection
FIT-201RAS Flow0-500 m³/hr4-20 mARAS Line
FIT-AIR-201Aeration Air Flow0-1000 Nm³/hr4-20 mAAir Supply Line

Analytical Instruments​

Tag IDParameterRangeOutputLocation
AIT-PH-101Influent pH0-14 pH4-20 mAAfter Grit Chamber
AIT-PH-104Aeration pH0-14 pH4-20 mAAeration Outlet
AIT-PH-106Effluent pH0-14 pH4-20 mAFinal Effluent
AIT-TSS-101Influent TSS0-1000 mg/L4-20 mAAfter Grit Chamber
AIT-TSS-104MLSS0-10000 mg/L4-20 mAAeration Tank
AIT-TSS-105Effluent TSS0-500 mg/L4-20 mAFinal Effluent
AIT-TDS-101Influent TDS0-2000 mg/L4-20 mAAfter Grit Chamber
AIT-TDS-106Effluent TDS0-2000 mg/L4-20 mAFinal Effluent
AIT-TMP-101Influent Temperature0-50 °C4-20 mAAfter Grit Chamber
AIT-TMP-104Aeration Temperature0-50 °C4-20 mAAeration Tank
AIT-TMP-106Effluent Temperature0-50 °C4-20 mAFinal Effluent

Instrument Tag Naming Convention​

Following ISA-5.1 standard:

[First Letter][Subsequent Letters]-[Loop Number]

First Letter (Measured Variable):
  F = Flow
  A = Analysis (quality)
  T = Temperature
  P = Pressure
  L = Level

Subsequent Letters (Function):
  I = Indicator
  T = Transmitter
  C = Controller
  V = Valve
  S = Switch

Examples:
  FIT-101 = Flow Indicator Transmitter, Loop 101
  AIT-PH-101 = Analyzer Indicator Transmitter for pH, Loop 101
  FV-201 = Flow Control Valve, Loop 201

Mapping to ML Model Parameters​

Instrument → TreatmentInput Mapping​

Instrument TagMeasured ParameterMaps ToUnits
AIT-PH-101Influent pHpHpH
AIT-TSS-101Influent TSSTSSmg/L
AIT-TDS-101Influent TDSTDSmg/L
FIT-101Influent Flowflow_ratem³/day
-TurbidityTurbidityNTU
-BODBODmg/L
-CODCODmg/L
-NH4-NNH4_Nmg/L
-Total NitrogenTotal_Nitrogenmg/L
-PhosphatePhosphatemg/L
-Fecal ColiformFecal_Coliformcount
-Oil & GreaseOil_Greasemg/L
-Heavy MetalsHeavy_Metalsmg/L

Instrument → WastewaterInput Mapping​

Instrument TagMeasured ParameterMaps ToUnits
FIT-101Influent Flowflow_ratem³/day
AIT-PH-101Influent pHinfluent_pHpH
AIT-TSS-101Influent TSSinfluent_TSSmg/L
AIT-TDS-101Influent TDSinfluent_TDSmg/L
AIT-TMP-101Influent Temperaturetemperature°C
FIT-AIR-201Aeration Rateaeration_ratekg O₂/hr
DOSE SPChemical Dose Setpointchemical_dosemg/L
FIT-201RAS Flow Ratesludge_recycle_rate%
-Retention Timeretention_timehours
AIT-TSS-105Effluent TSSeffluent_TSSmg/L
AIT-TDS-106Effluent TDSeffluent_TDSmg/L
AIT-PH-106Effluent pHeffluent_pHpH

Control Loops​

Loop 1: Aeration Control (FIC-AIR-201)​

┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│ AIT-TSS-104 │────▶│    PLC      │────▶│   FV-201    │
│   (MLSS)    │     │  (DO/MLSS   │     │ (Air Valve) │
└─────────────┘     │   Control)  │     └─────────────┘
                    └─────────────┘
                          │
                          ▼
                    ┌─────────────┐
                    │   BL-201    │
                    │  (Blower)   │
                    └─────────────┘

Control Strategy: Maintain MLSS at setpoint (2500-3500 mg/L) by adjusting aeration rate.

Loop 2: RAS Flow Control (FIC-201)​

┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│  FIT-201    │────▶│    PLC      │────▶│   P-201     │
│ (RAS Flow)  │     │  (Ratio     │     │ (RAS Pump)  │
└─────────────┘     │   Control)  │     └─────────────┘
                    └─────────────┘
                          ▲
                          │
                    ┌─────────────┐
                    │  FIT-101    │
                    │(Infl. Flow) │
                    └─────────────┘

Control Strategy: Maintain RAS flow at 25-50% of influent flow.

Loop 3: Chemical Dosing (FIC-301)​

┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│  FIT-105    │────▶│    PLC      │────▶│   P-301     │
│(Effl. Flow) │     │  (Flow      │     │(Dosing Pump)│
└─────────────┘     │  Pacing)    │     └─────────────┘
                    └─────────────┘
                          ▲
                          │
                    ┌─────────────┐
                    │  DOSE SP    │
                    │ (Setpoint)  │
                    └─────────────┘

Control Strategy: Flow-paced chemical dosing based on effluent flow rate.

Process Stream Data​

Stream Compositions (Design Basis)​

StreamFlow (m³/hr)pHTSS (mg/L)BOD (mg/L)COD (mg/L)TDS (mg/L)
S-10110006.8300350700800
S-10210006.9250320650780
S-1039807.0120200400750
S-1041200*7.23000**80180700
S-1059507.3302570650
S-1069507.5101030600
S-2012507.28000**50120680

*Includes RAS flow
**MLSS concentration

Alarm & Trip Settings​

Critical Alarms​

TagParameterLow AlarmHigh AlarmTrip
AIT-PH-101Influent pH5.59.05.0 / 10.0
AIT-TSS-104MLSS150050001000/6000
FIT-101Influent Flow1001800-
AIT-PH-106Effluent pH6.09.05.5 / 9.5
AIT-TSS-105Effluent TSS-50100

CAD Model Component Selection​

When a user clicks on a component in the 3D CAD model, the following data is extracted:

Example: Clicking on AER-01 (Aeration Tank)​

const aerationTankMetadata = {
  // Equipment Info
  tagId: "AER-01",
  name: "Aeration Tank",
  type: "aeration_tank",

  // Associated Instruments
  instruments: [
    { tag: "FIT-AIR-201", parameter: "aeration_rate", value: 500 },
    { tag: "AIT-PH-104", parameter: "pH", value: 7.2 },
    { tag: "AIT-TSS-104", parameter: "TSS", value: 3000 },
    { tag: "AIT-TMP-104", parameter: "temperature", value: 22 },
  ],

  // Inlet Stream (S-103)
  inletStream: {
    streamId: "S-103",
    pH: 7.0,
    TSS: 120,
    BOD: 200,
    COD: 400,
    TDS: 750,
  },

  // Outlet Stream (S-104)
  outletStream: {
    streamId: "S-104",
    pH: 7.2,
    TSS: 3000, // MLSS
    BOD: 80,
    COD: 180,
    TDS: 700,
  },

  // Operational Parameters
  operational: {
    flow_rate: 1000,
    aeration_rate: 500,
    retention_time: 6,
    sludge_recycle_rate: 25,
    temperature: 22,
  },
};

Additional Instruments (Future Enhancement)​

The following instruments can be added for more comprehensive monitoring:

Tag IDParameterPurpose
AIT-DO-104Dissolved OxygenAeration optimization
AIT-NH4-104Ammonia NitrogenNitrification monitoring
AIT-NO3-105NitrateDenitrification monitoring
AIT-PO4-105PhosphateP removal monitoring
AIT-ORP-104ORPRedox potential
AIT-TURB-105TurbidityEffluent quality
AIT-COD-105COD (online)Real-time COD monitoring
AIT-BOD-105BOD (estimated)Calculated from COD
LIT-101Primary Clarifier LevelLevel control
LIT-201Aeration Tank LevelLevel control

References​

  • ISA-5.1-2009: Instrumentation Symbols and Identification
  • ISA-5.4-1991: Instrument Loop Diagrams
  • CPCB Guidelines for STPs
  • EPA Design Manual for Municipal Wastewater Treatment Plants

Document Version: 1.0
Last Updated: December 2024