02 - Hardware Sensors

Recommended sensors, devices, and hardware specifications for water quality monitoring

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Table of Contents

1. Water Quality Sensors
2. Edge Computing Devices
3. Communication Hardware
4. Power & Installation
5. Vendor Recommendations
6. Cost Estimation

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1. Water Quality Sensors

1.1 Core Parameter Sensors

Parameter	Sensor Type	Range	Output	Accuracy	Recommended Model
pH	Glass Electrode	0-14 pH	4-20mA	±0.02 pH	Hach PHD sc / E+H Orbisint CPS11D
BOD	Respirometric	0-1000 mg/L	Modbus	±5%	Hach BioTector B3500
COD	UV-Vis Spectro	0-5000 mg/L	Modbus	±3%	Hach UVAS sc / LAR QuickCOD
TSS	Optical	0-50000 mg/L	4-20mA	±2%	Hach Solitax sc
TDS	Conductivity	0-200000 µS/cm	4-20mA	±1%	E+H Condumax CLS21D
Turbidity	Nephelometric	0-4000 NTU	4-20mA	±2%	Hach TU5300 sc
Flow Rate	Electromagnetic	0.5-10 m/s	4-20mA	±0.5%	Siemens SITRANS FM MAG 5100W
Temperature	RTD Pt100	-50 to 200°C	4-20mA	±0.1°C	E+H Omnigrad M TR10
DO	Optical	0-20 mg/L	4-20mA	±0.1 mg/L	Hach LDO2 sc
NH4-N	Ion Selective	0.1-1000 mg/L	Modbus	±5%	Hach AMTAX sc

1.2 Sensor Specifications for ML Model Compatibility

// Required sensor data format for ML models
interface SensorReading {
  parameter: string;
  value: number;
  unit: string;
  timestamp: ISO8601;
  quality: "good" | "uncertain" | "bad";
  sensorId: string;
}

// Example mapping for Prediction Model
const predictionModelInputs = {
  flow_rate: { unit: "m³/hr", range: [0, 500] },
  influent_BOD: { unit: "mg/L", range: [0, 1000] },
  influent_COD: { unit: "mg/L", range: [0, 5000] },
  influent_TSS: { unit: "mg/L", range: [0, 1000] },
  influent_pH: { unit: "pH", range: [0, 14] },
  influent_TDS: { unit: "mg/L", range: [0, 10000] },
  temperature: { unit: "°C", range: [0, 50] },
};

1.3 Installation Locations

┌─────────────────────────────────────────────────────────────────────┐
│                    WASTEWATER TREATMENT PLANT                        │
│                                                                      │
│  ┌──────────┐    ┌──────────┐    ┌──────────┐    ┌──────────┐      │
│  │ INLET    │───▶│ PRIMARY  │───▶│ SECONDARY│───▶│ TERTIARY │      │
│  │          │    │ TREATMENT│    │ TREATMENT│    │ TREATMENT│      │
│  └──────────┘    └──────────┘    └──────────┘    └──────────┘      │
│       │               │               │               │             │
│       ▼               ▼               ▼               ▼             │
│  ┌─────────┐    ┌─────────┐    ┌─────────┐    ┌─────────┐         │
│  │SENSORS: │    │SENSORS: │    │SENSORS: │    │SENSORS: │         │
│  │• pH     │    │• TSS    │    │• BOD    │    │• All    │         │
│  │• Flow   │    │• pH     │    │• COD    │    │• Params │         │
│  │• Temp   │    │         │    │• DO     │    │         │         │
│  └─────────┘    └─────────┘    └─────────┘    └─────────┘         │
│                                                                      │
└─────────────────────────────────────────────────────────────────────┘

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2. Edge Computing Devices

2.1 Industrial Edge Gateways

Device	Processor	Memory	I/O	Protocols	Price Range
Siemens SIMATIC IOT2050	ARM Cortex-A53	2GB DDR4	2x Ethernet, RS232/485	OPC-UA, MQTT, Modbus	$400-600
Advantech WISE-710	Intel Atom	4GB DDR4	4x COM, 2x LAN	MQTT, REST, OPC-UA	$500-800
Dell Edge Gateway 5000	Intel Atom	8GB DDR4	USB, Serial, Ethernet	All major protocols	$800-1200
Moxa UC-8100-ME	ARM Cortex-A8	1GB DDR3	2x RS-232/422/485	Modbus, MQTT	$300-500

2.2 Recommended Configuration

# Edge Gateway Specifications for Water Treatment
edge_gateway:
  model: "Siemens SIMATIC IOT2050"
  specifications:
    processor: "ARM Cortex-A53 Dual Core"
    ram: "2GB DDR4"
    storage: "16GB eMMC + SD Card"
    os: "Industrial Linux (Debian-based)"

  interfaces:
    ethernet:
      - port: "X1 P1"
        use: "Sensor Network (Modbus TCP)"
      - port: "X1 P2"
        use: "Cloud Connection (MQTT)"
    serial:
      - port: "RS485"
        use: "Legacy Modbus RTU sensors"

  software:
    - Node-RED (flow programming)
    - MQTT Client (Paho)
    - OPC-UA Server
    - SQLite (local buffering)

2.3 PLCs for Industrial Integration

PLC	Manufacturer	Communication	Use Case
SIMATIC S7-1500	Siemens	PROFINET, OPC-UA	Large plants
CompactLogix 5380	Allen-Bradley	EtherNet/IP	US installations
Modicon M340	Schneider	Modbus TCP, Ethernet	Medium plants
MELSEC iQ-R	Mitsubishi	CC-Link, Ethernet	Asian markets

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3. Communication Hardware

3.1 Network Infrastructure

┌─────────────────────────────────────────────────────────────────────┐
│                    NETWORK TOPOLOGY                                  │
│                                                                      │
│  ┌─────────────┐                           ┌─────────────┐          │
│  │ CLOUD       │◀──── Internet ────────────│ ROUTER      │          │
│  │ (AWS/Azure) │     (4G/5G/Fiber)         │ (Firewall)  │          │
│  └─────────────┘                           └──────┬──────┘          │
│                                                   │                  │
│                                            ┌──────┴──────┐          │
│                                            │ INDUSTRIAL  │          │
│                                            │ SWITCH      │          │
│                                            └──────┬──────┘          │
│                          ┌────────────┬──────────┼──────────┐       │
│                          │            │          │          │       │
│                    ┌─────┴─────┐ ┌────┴────┐ ┌───┴───┐ ┌───┴───┐  │
│                    │ EDGE      │ │ PLC     │ │ SCADA │ │ HMI   │  │
│                    │ GATEWAY   │ │         │ │ SERVER│ │       │  │
│                    └─────┬─────┘ └────┬────┘ └───────┘ └───────┘  │
│                          │            │                            │
│                    ┌─────┴─────┐ ┌────┴────┐                       │
│                    │ SENSORS   │ │ FIELD   │                       │
│                    │ (Modbus)  │ │ DEVICES │                       │
│                    └───────────┘ └─────────┘                       │
└─────────────────────────────────────────────────────────────────────┘

3.2 Required Network Equipment

Equipment	Specification	Recommended Model
Industrial Switch	Managed, 8+ ports, PoE	Cisco IE-4000-8P4G-E
Cellular Router	4G/5G, dual SIM	Sierra Wireless RV55
Serial Converter	RS-485 to Ethernet	Moxa NPort 5110
Protocol Converter	Modbus to OPC-UA	Kepware KEPServerEX

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4. Power & Installation

4.1 Power Requirements

Component	Voltage	Power	Backup
Sensors (typical)	24V DC	5-20W each	UPS recommended
Edge Gateway	24V DC	15-30W	UPS required
Network Switch	24V DC / 48V PoE	30-100W	UPS required
PLC	24V DC	50-200W	UPS required

4.2 Enclosure Requirements

outdoor_installation:
  enclosure_rating: "IP66 minimum"
  material: "Stainless Steel 316 (corrosive environments)"
  cooling: "Thermoelectric or AC if ambient > 40°C"
  dimensions: "800x600x300mm (typical)"

indoor_installation:
  enclosure_rating: "IP54 minimum"
  material: "Powder-coated steel"
  cooling: "Natural ventilation or fan"

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5. Vendor Recommendations

5.1 Tier 1 (Premium)

Vendor	Specialty	Products
Hach (Danaher)	Water quality sensors	BioTector, LDO, pH sensors
Endress+Hauser	Process instrumentation	Complete sensor portfolio
Siemens	Automation & edge	IOT2050, SIMATIC PLCs
ABB	Flow & analytics	Electromagnetic flow meters

5.2 Tier 2 (Mid-Range)

Vendor	Specialty	Products
Yokogawa	Process sensors	pH, ORP, conductivity
Thermo Fisher	Analytical sensors	Orion series
Advantech	Edge computing	WISE series gateways

5.3 Tier 3 (Budget-Friendly)

Vendor	Specialty	Products
Apera Instruments	pH/conductivity	AI series
Atlas Scientific	DIY sensors	EZO series (Arduino compatible)
Raspberry Pi	Edge computing	Pi 4 + industrial HATs

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6. Cost Estimation

6.1 Small Plant (< 1 MLD)

Category	Items	Estimated Cost (USD)
Sensors	pH, Flow, TSS, COD	$15,000 - 25,000
Edge Gateway	1x Industrial gateway	$500 - 1,000
Network	Switch, router, cabling	$2,000 - 3,000
Installation	Labor, enclosures	$5,000 - 8,000
Total		$22,500 - 37,000

6.2 Medium Plant (1-10 MLD)

Category	Items	Estimated Cost (USD)
Sensors	Full parameter suite (10+)	$50,000 - 80,000
Edge Gateway	2-3x Industrial gateways	$2,000 - 4,000
PLC/SCADA	Siemens S7-1500 + HMI	$15,000 - 25,000
Network	Managed infrastructure	$5,000 - 10,000
Installation	Labor, commissioning	$15,000 - 25,000
Total		$87,000 - 144,000

6.3 Large Plant (> 10 MLD)

Category	Items	Estimated Cost (USD)
Sensors	Multi-point monitoring	$150,000 - 250,000
Control System	Full DCS/SCADA	$100,000 - 200,000
Edge/Cloud	Redundant infrastructure	$20,000 - 40,000
Integration	Software, licensing	$30,000 - 50,000
Installation	Full project	$50,000 - 100,000
Total		$350,000 - 640,000

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Next Steps

• Proceed to 03-SOFTWARE-STACK.md for software platform selection
• Review 04-PROTOCOL-ADAPTERS.md for connecting these sensors

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Last Updated: December 2024