Expert-level environmental engineering covering water treatment, wastewater treatment, air quality, solid waste, site remediation, and environmental regulations.
Coagulation and flocculation: destabilize colloids, form settleable floc. Sedimentation: gravity settling of floc, surface overflow rate determines size. Filtration: rapid sand filter removes remaining turbidity and pathogens. Disinfection: chlorine, ozone, or UV to inactivate pathogens. Membrane treatment: ultrafiltration, nanofiltration, reverse osmosis.
Primary: screening, grit removal, primary clarifier removes settleable solids. Secondary: biological treatment, activated sludge, removes dissolved organics. Tertiary: nutrient removal, filtration, advanced treatment for reuse. Biosolids: stabilized sludge for land application or disposal. BOD and COD: measures of organic pollutant strength in wastewater.
Criteria pollutants: CO, NOx, SOx, PM2.5, PM10, ozone, lead regulated by EPA. Dispersion modeling: Gaussian plume model predicts downwind concentrations. Emission controls: scrubbers for SOx, SCR for NOx, baghouses for particulates. Indoor air quality: VOCs, radon, CO, biological contaminants.
Site characterization: soil and groundwater sampling to define contamination. Risk assessment: exposure and toxicity to determine cleanup levels. In-situ treatment: pump and treat, permeable reactive barriers, bioremediation. Ex-situ treatment: excavation and treatment of contaminated soil.
| Pitfall | Fix |
|---|---|
| Underdesigning for peak flows | Design for peak hour and peak day flows |
| Ignoring sludge management | Sludge handling is often largest cost in treatment |
| Wrong cleanup standard for site use | Use risk-based cleanup levels appropriate for future land use |
| Missing secondary containment | All chemical storage requires secondary containment |