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ECW542

Wastewater Engineering Lecturer:

Tower 1/ Aras

, Room

Ext. Advanced Treatment DA/RH


ADVANCED TREATMENT

Tertiary Treatment & Higher Quality Effluent


ADVANCED TREATMENT

FILTRATION Supplemental

removal of suspended solids from effluent of biological and chemical processes. Requirement for pretreatment for disinfection processes to improve efficiency Requirement for pretreatment for other physical chemical treatments


ADVANCED TREATMENT

DISINFECTION CHLORINATIONDisinfection of

effluent to remove microbial

pollutants Usually carried out if discharging into sensitive receiving waters, eg bathing waters, or effluent is reuse. UV Better alternative for disinfection No toxic chlorine residues.


ADVANCED TREATMENT

SOURCE OF NITROGEN IN WASTEWATER Nitrogen

exists in several forms: Ammonium, Organic Compound [NH4]+, Nitrite [NO2]-, Nitrate [NO3]N came from protein metabolism in human body, 60% in organic form 40% in ammonium form Typical N is wastewater is about 40 mg/L (2085 mg/L) Other sources of N- infiltration, from sludge treatment, decomposition of microbes, industrial discharge, kitchen waste


ADVANCED TREATMENT

N

 deplete O2, fertilise aquatic plants, exhibit toxicity to aquatic life, affect chlorine disinfection, public health hazards, in drinking watermethemoglobinemia

PHYSICAL/CHEMICAL PROCESSES FOR NITROGEN REMOVAL Breakpoint Chlorination for Removal of Ammonia-N Air Stripping for Removal of Ammonia-N Selective Ion Exchange to Remove AmmoniumN ion or Nitrate-N ion


ADVANCED TREATMENT

BIOLOGICAL

PROCESSES FOR NITROGEN

REMOVAL

Assimilation

of bacterial cells and through waste of sludge Transformation of organic N to nitrogen gases through nitrification and denitrification processes: 2NH4+ + 3O2 nitrosomonas 2NO2- + 2H2O + 4H+ + cell 2NO2- + O2 nitrobacter 2NO3- + cell


ADVANCED TREATMENT

EUTROPHICATION Process

whereby lakes become enriched with nutrients that make the water undesirable for human use, consumption & recreation Nutrients unbalance the normal succession  blue-green algae bloom  not utilised by zooplankton Decomposed algae  odour Decaying algae at the bottom  reduce DO level  reduce fish Complicated water treatment of algae to remove odour & taste  sunlit epilimnion and anaerobic conditions in epilimnion


ADVANCED TREATMENT

Promote

plant growth (eg water hycin) and only tolerant fish survived  unsuitable for recreation To overcome  reduce level of phosphorus discharged to lakes


ADVANCED TREATMENT Biological Nitrogen Removal Secondary Clarifier

Influent

Effluent

Aeration Tank Anoxic Zone Return Activated Sludge Waste Activated Sludge

ďƒ­Refer Sec.8-5, p.749, Metcalf & Eddy (2004)


ADVANCED TREATMENT Biological Phosphorus Removal Secondary Clarifier

Influent

Effluent

Aeration Tank Anaerobic Zone Return Activated Sludge Waste Activated Sludge

ďƒ­Refer Sec.8-6, p.799, Metcalf & Eddy (2004)


THANK YOU

ECW542-wk13-L37  

ECW542 Advanced Treatment Lecturer: DA/RH Tertiary Treatment & Higher Quality Effluent ADVANCED TREATMENT  Requirement for pretreatment...

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