Recommendations for handling and dosing devices for chemicals for water treatment, Part I: Coagulants

IS 9222 Part 1 — Scope Summary & Key References

• Scope: Specifies requirements for solution feed devices (chlorinators, bleaching powder feeders) and related equipment.
• Rounding off: Final test/calculated values must be rounded per IS 2:1960 rules, retaining the same significant figures as specified.
• Solution Concentration: Refer to Table 1 in the standard for recommended solution strengths.
• Referenced IS Codes: Annex A lists essential Indian Standards related to materials, electrical installations, safety, and equipment, e.g.:
  • IS 210: Grey iron castings
  • IS 260: Aluminium sulphate
  • IS 325: Three-phase induction motors
  • IS 732 (Parts 1-3): Electrical wiring installation codes
  • IS 1435: Platform weighing machines
  • IS 5216: Safety procedures in electrical work

Table 1 (Example: Solution Concentration Reference)

Notes:

• Use the Standard Mark under BIS supervision to ensure compliance.
• Keep updated with amendments from BIS.
• For detailed specs, consult the full IS 9222 Part 1 document and Annex A for related IS codes.

flowchart LR
    A[IS 9222 Part 1 Scope] --> B[Solution Feed Devices]
    A --> C[Rounding off per IS 2:1960]
    A --> D[Solution Concentration - Table 1]
    A --> E[Referenced IS Codes - Annex A]
    E --> F[IS 210, IS 260, IS 325, IS 732, IS 1435, IS 5216]

This concise overview helps ensure correct application and compliance with IS 9222 Part 1.

IS 9222 Part 1 - Referenced Indian Standards Summary

Key Points from Clause 2.1 and Annex A:

• The standard references multiple Indian Standards (IS) essential for compliance, covering materials, equipment, and safety.
• Examples of referenced IS include:

• These referenced standards ensure material quality, safety, and performance for components used in solution feed devices.

Rounding Off Values (IS 2:1960)

• Final test values must be rounded off following IS 2:1960 rules.
• Retain the same number of significant digits as specified in the standard.

Practical Use:

• Always consult the relevant IS listed for detailed specifications on materials and equipment.
• Use IS 2:1960 for rounding numerical results to maintain consistency.

flowchart LR
    A[IS 9222 Part 1] --> B[Annex A: Referenced IS]
    B --> C[Material Standards (e.g., IS 210)]
    B --> D[Equipment Standards (e.g., IS 325)]
    B --> E[Safety & Installation (e.g., IS 732)]
    A --> F[Rounding off per IS 2:1960]

For detailed design or testing, refer to the individual IS documents listed in Annex A.

IS 9222 Part 1: General Recommendations for Handling Coagulants

Key Points from Table 1 (Clause 8.2):

IS 9222 Part 1: Storage of Coagulants - Key Specifications & Tables

Storage Requirements (Clauses 4.2 & 4.5)

• Storage Room: Damp-proof to prevent moisture ingress.
• Storage Space Near Feed: Minimum 1 week's supply near feeding device for operational convenience.
• Flood Protection: Special precautions to avoid flooding damage.

Table 1: Common Coagulants Storage & Handling Summary

Weighing and Measuring Coagulants (IS 9222 Part 1)

Key Specifications:

• Clause 5.1: Predetermined quantities of coagulants must be weighed accurately both on receipt and before feeding.
• Clause 5.2: Use weighing machines conforming to:
  • IS 1435 : 1960 (Platform Scales)
  • IS 1439 : 1959 (Spring Balances)
  • IS 1854 : 1964 (Weights)

Common Coagulants (Table 1 Highlights):

Preparation & Feeding:

• Preparation: Slowly add powder to water with stirring to avoid dust combustion.
• Feeding: Gravity feed preferred for solutions; granules or powder can be fed dry.
• Storage: Tanks must be corrosion-resistant and protected against moisture.

Formula for Solution Preparation:

[ \text{Weight of coagulant} = \text{Volume of solution} \times \text{Strength of solution} \times \text{Density of solution} ]

flowchart LR
    A[Coagulant Receipt] --> B[Weighing (IS 1435, 1439, 1854)]
    B --> C[Preparation Tank]

IS 9222 Part 1: Solution Tanks and Preparation - Key Points

1. Number and Capacity of Tanks (Clause 6.1)

• Minimum 3 tanks for continuous operation (8 hours dosing each):
  • 1 for preparation
  • 1 for dosing
  • 1 standby (cleaning/preparation)
• If daily coagulant use ≤ 5000 L, 2 tanks suffice (each holds 24-hour solution).
• For large quantities, multiple tanks to meet 8-hour dose.

2. Tank Design (Clause 6.2)

• Tanks can be square, rectangular, or circular.
• Must have mixing devices for intimate chemical mixing.

3. Chemical Preparation & Storage (Table 1 summary)

4. Weighing Equipment (Clause 5.2)

• Use weighing machines conforming to IS 1435, IS 1439, IS 1854 for dosing accuracy.

Summary Diagram of Solution Tank Setup

flowchart LR
    A[Raw Chemicals] --> B[Weighing Machine]
    B --> C[Preparation Tank with Mixer]
    C --> D[Dosing Tank]
    D --> E[Chemical Feed to Process]
    C --> F[Standby Tank (Clean/Ready)]

Note: Mixing devices and corrosion-resistant materials are

Mixing Devices for Coagulant Solutions
(IS 9222 Part 1: Clauses 7.1, 8.2, 9.2)

Key Specifications:

1. Mixing Methods (Clause 7.1):

• Mechanical Agitation:

  • Turnover capacity: 2 hours for alum solution tank.
  • Motor: Totally-enclosed fan-cooled.
  • Shaft: Material as per 7.1(c).
  • Paddles: Stainless steel, wood, polypropylene, or fiberglass.
  • Bottom guide: Stainless steel.
  • Gears: Mounted on concrete with cast iron housing.

• Compressed Air Agitation:

  • Air supply: 0.1 to 0.15 m³/min per m³ of tank volume.
  • Pipe materials: HDPE, unplasticized PVC, or polypropylene.

2. Coagulant Solution Preparation (Table 1, Clause 8.2):

• Alum, Ferric chloride, Ferric sulphate, etc.
• Solutions typically prepared by dissolving powder or lumps in water with stirring.
• Strengths vary (e.g., Alum up to 10%, Ferric chloride 3-4%, Ferric sulphate up to 25%).
• Storage tanks must be corrosion-resistant (concrete lined with acid-proof bricks, steel painted, or plastic-lined).

3. Feeding Devices (Clause 9.2):

• Pumps made from corrosion-resistant materials (see Table 1 for suitable materials).
• Ejectors also used for proportionate feeding.

Summary Table for Mixing Devices:

Important Notes:

• Ensure complete dissolution before stirring.

IS 9222 Part 1: Solution Feed and Drain Lines Key Points

Material & Durability (Clause 8.2)

• Use corrosion-resistant materials as per Table 1.
• Lines must be durable and accessible for maintenance.

Diameter Specifications

Layout & Installation (Clauses 8.2 & 8.3)

• Avoid air trapping in lines.
• Provide cleaning eyes at sharp bends.
• Rubber hoses supported in troughs with easy bends.
• Protect lines against freezing where applicable.

Maintenance (Clause 8.4)

• Provide water flushing connections conveniently.
• Clean coagulant feed lines frequently to prevent choking.

Summary Table:

flowchart LR
    A[Solution Tank] -->|Gravity feed ≥ 50mm| B[Solution Feed Line]
    B -->|Sharp bends with cleaning eye| C[Coagulant Feed Device]
    C -->|Pressure feed ≥ 25mm| D[Injection Point]
    D --> E[Drain Line ≥ 100mm]
    E --> F[Disposal]
    style B fill:#f9f,stroke:#333,stroke-width:2px
    style E fill:#bbf,stroke:#333,stroke-width:2px

Use filtered or settled clear water for preparing coagulants (Clause 7.3).

IS 9222 Part 1: Solution Feed Devices Key Points

• Purpose: Regulate coagulant dosing into water (Clause 9.1).

• Flow Measurement: Use rotameter, orifices, or calibrated weirs with scale plates.

• Material: Non-corrodible construction for solution feed equipment.

• Strainers: Installed before feed devices; removable for cleaning to prevent clogging.

• Feeding Mechanism (Clause 9.1.1):

  • Positive displacement pumps or constant head devices recommended for feeding.

• Flushing (Clause 8.4):

  • Water connections for flushing solution lines should be accessible; frequent cleaning to avoid choking.

• Stirring & Recirculation (Clause 4.65):

  • Continuous stirring essential; air agitation: 5 min on, 20-30 min rest cycle.
  • Recirculation pump capacity: turnover tank volume in 2 hours.
  • Pump parts: stainless steel/polypropylene impeller, shaft, sleeve; cast iron body (IS 210:1978).
  • Motor: Totally enclosed fan cooled (TEFC), IC41 cooling (IS 6362:1971), IP54 protection or better (IS 4691:1985).

Typical Formula for Pump Capacity (Recirculation):

[ Q = \frac{V}{t} ]

Where:

• (Q) = Pump flow rate (m³/hr)
• (V) = Volume of solution tank (m³)
• (t) = Turnover time (hr), typically 2 hr

Summary Table: Solution Feed Device Features

flowchart LR
    A[Coagul

IS 9222 Part 1: Safety and Maintenance Considerations for Chemical Handling in Water Treatment

Key Specifications from Clause 8.2 & Table 1:

• Chemical Properties & Handling:

  • Coagulants like Aluminium Sulphate, Ferric Chloride, Ferric Sulphate, Sodium Aluminate, etc., are acidic or alkaline, corrosive, and hygroscopic.
  • Special attention required for dustiness, corrosiveness, and hygroscopic nature.

• Storage:

  • Use corrosion-resistant materials: concrete with acid-proof bricks, PVC, rubber-lined steel, stainless steel, or plastic containers.
  • Store in ventilated, cool, and dry spaces.
  • Use hessian or polyethylene bags for powders; drums or carboys for liquids.

• Preparation & Feeding:

  • Powders: Slowly add to water with stirring to avoid dust explosions.
  • Solutions: Gravity feed or chemical feed pumps recommended.
  • Strength of solutions typically ranges from 3% to 25% depending on chemical.
  • Feeding forms: dry powder, granules, or liquid solutions.

Safety Recommendations:

• Follow IS 732 and IS 5216 for electrical safety during installation of dosing devices.
• Use appropriate personal protective equipment (PPE) due to corrosive and toxic nature.
• Ensure proper ventilation and spill containment.
• Regular maintenance of dosing pumps and mixers to avoid clogging and leaks.

Summary Table (Example for Aluminium Sulphate):

flowchart TD
    A[Chemical Storage] --> B[Preparation]
    B --> C[Feeding System]
    C --> D[Water Treatment Process]
    A -. Safety Measures .-> E[PPE & Ventilation]
    B -. Safety Measures