Wastewater Treatment q Overview and DO Model in

Wastewater Treatment q Overview and DO Model in rivers q WW flow rate q WW characteristics q WW treatment

Water & Wastewater (Overview) Why do we treat wastewater? – To protect the health of the receiving area • Water reuse • Alternate water resources • Aesthetics – To protect the health of humans

Wastewater Characteristics

Dissolved-Oxygen (DO) Sag Curve Model (Streeter and Phelps Model) D= Oxygen deficit (mg/L)= Cs-C D 0 = Initial oxygen deficit (mg/L) Kd= De-oxygenated rate constant (1/d) L 0 = Initial Ultimate BOD= BODu (mg/L) KR= re-aeration constant (1/d)

Wastewater Flow rate Typical variation in flow , SS, BOD q Short term: Hourly, Daily, Weekly q Long Term: Monthly, Yearly

Wastewater Characteristics List of wastewater contaminants and their impacts Contaminants ) Suspended solid 2) Biodegradable organics Pathogen 4) Nutrient (N, P) Main Sources Domestic / industrial WW Environmental impacts Runoff sludge deposit in rivers & Dams Domestic / industrial WW biological degradation Agriculture activity DO depletion Domestic WW / Runoff Transmit diseases Domestic / industrial WW Eutriphication Agriculture activity 5) Refractory organics Industrial waste Taste/order, Toxicity 6) Heavy metals Industrial waste / Toxicity

Wastewater Treatment Municipal WW treatment system: - Primary : To remove solid materials - Secondary : To remove Organic matters - Tertiary: To remove specific contaminants

Wastewater Treatment A Typical process flow diagram

A Typical process flow diagram

Wastewater Treatment Primary Treatment Bar Racks Grit Chambers Flow Equalization Preliminary Sedimentation

Wastewater Treatment Secondary Treatment Biological Treatment Activated Sludge Trickling Filter Rotating Biological Contactor Secondary Clarification Disinfection

Wastewater Treatment Bar Screening (1)

Wastewater Treatment Flume (flow meter)

Wastewater Treatment Primary Sedimentation

Wastewater Treatment Primary Sedimentation

Wastewater Treatment Suspended Growth: Activated sludge Process

Wastewater Treatment Aeration Tank in Activated sludge Process

Wastewater Treatment Secondary Sedimentation

Wastewater Treatment Chlorination

Biological Wastewater Treatment RBC (1)

Biological Wastewater Treatment RBC (2)

Biological Wastewater Treatment Attached growth: Trickling Filters (TF)

Biological Wastewater Treatment Trickling Filters

Biological Wastewater Treatment Membrane Bio Reactors: MBR

Biological Wastewater Treatment Lagoons

Biological Wastewater Treatment Wetland (Malaysia)