Water Treatment Expert

---
name: water-treatment-expert
version: 1.0.0
description: Expert-level water treatment covering drinking water treatment, wastewater treatment, industrial water systems, membrane processes, and water reuse.
author: luo-kai
tags: [water treatment, drinking water, wastewater, membranes, disinfection, water reuse]
---

# Water Treatment Expert

## Before Starting
1. Drinking water, wastewater, or industrial water?
2. Municipal or industrial scale?
3. Conventional or advanced treatment?

## Core Expertise Areas

### Drinking Water Treatment
Coagulation: alum or ferric sulfate destabilizes colloidal particles.
Flocculation: gentle mixing grows floc particles for settling.
Sedimentation: gravity settling removes floc, SOR determines tank size.
Filtration: rapid sand or dual media filter removes remaining turbidity.
Disinfection: chlorine, chloramines, ozone, or UV inactivate pathogens.

### Wastewater Treatment
Preliminary: screening, grit removal protect downstream processes.
Primary clarifier: 60-70% SS removal, 30-40% BOD removal by settling.
Activated sludge: aerobic biological oxidation of dissolved organics.
Secondary clarifier: separate biological solids from treated effluent.
Nutrient removal: biological nitrogen and phosphorus removal processes.

### Membrane Processes
MF and UF: remove suspended solids, bacteria, protozoa by size exclusion.
NF: removes divalent ions, partial desalination, hardness removal.
RO: removes dissolved salts, desalination, water reuse.
MBR: membrane bioreactor combines activated sludge and membrane filtration.
Fouling control: pretreatment, cleaning protocols, flux management.

### Water Reuse
Indirect potable reuse: treated recycled water to groundwater or reservoir.
Direct potable reuse: advanced treated water directly to drinking supply.
Non-potable reuse: irrigation, industrial cooling, toilet flushing.
Advanced treatment: MF plus RO plus UV plus advanced oxidation for potable reuse.

## Best Practices
- Conduct jar testing before full scale coagulant dosing changes
- Maintain disinfectant residual throughout distribution system
- Monitor membrane integrity regularly with pressure decay testing
- Design for peak flows with adequate capacity factor

## Common Pitfalls
| Pitfall | Fix |
|---|---|
| Insufficient disinfection contact time | Calculate CT value and verify against pathogen inactivation table |
| Membrane fouling from inadequate pretreatment | SDI below 3 required for RO feed water |
| Biological process upsets from toxic influent | Provide equalization and toxicity monitoring |
| Wrong sludge age for nitrification | Maintain SRT above minimum for nitrifying organisms |

## Related Skills
- air-quality-expert
- environmental-remediation-expert
- hydraulics-expert