WASTEWATER TREATMENT Lili sugiyarto
WASTEWATER
TREATMENT
Lili sugiyarto
Lili_sugiyarto@uny.ac.id
The primary goal
The removal and degradation of organic matter under controlled condition
Three major steps
Primary treatment
Secondary treatment
Tertiary treatment
Primary treatment
A physical process that involves the separation of large debries, followed by sedimentation
Comprises grit tank and settling tank
Settling tank also known as sedimentation tank (sand and gravel)/clarifier
About half suspended organic solids settle to the bottom as sludge or biosolids
(primary sludge)
Secondary treatment
Consist of biological degradation
(decomposed and the number of pathogens is reduced)
The effluent from primary treatment may be pumped into a tricklingfilter bed ( an aeration tank/a sewage lagoon
Disinfection step is generally included at the end of treatment
Large-scale wastewater treatment
Trickling filter bed
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Rocks provide a matrix supporting the growth of a microbial biofilm that actively degrades the organic material under aerobic conditions
Effluen from primary treatment is pumped into a tank and mixed with bacteria-rich known as activated sludge air and pure oxygen pumped through the mixture promotes bacterial growth and decomposition of the organic material
Then goes to a secondary settling tank
Water siphon off the top of the tank
Sludge is removed from the bottom
Some of the sludge is used as an inoculum for the incoming activated sludge
The sludge that is not return as secondary sludge
Trickling filters
Gram negative bacteria : Zooglea,
Pseudomonas, Alcaligenes,
Achromobacter, Flavobacterium
Gram positive : Corynebacterium, etc
Fungi : Fusarium, Trisporon, Ascoidea
In secondary treatment
It contains a high level of the organic nutrients phosphate and nitrate
Nitrosomonas : oxidize ammonia to nitrite
Nitrobacter : oxidize nitrite to nitrate
Secondary treatment
Aerobic digestion tank
Anaerobic digestion tank
Anaerobic digestion tank
The degradatif and fermentative process divided into 2 stages : acid forming and methane forming
Genera of Methane forming stage :
Methanobacterium, Methanosarcina,
Methanococcus (convert acetate, hydrogen and CO2 to methane)
The major metabolic stages
Complex organic compounds
(polysaccharides, fats, protein)
Hydrolisis
Hydrolysis by extracellular bacterial enzymes
Monomeric compounds (sugar, fatty acids, amino acids)
Higher organic acids Acidogenesis
Acetic acid, H2, CO2
CH4
Acetogenesis methanogenesis
Types of Bioremediation
In situ bioremediation
Composting
Landfarming
Above-ground bioreactors
Activated sludge process
Activated sludge flocs
Note filamentous bacteria
Note Vorticella and other protozoa
Activated sludge model
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0
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Composition of sludge © PK, 2006 - page 21
• Predominantly water
• Micro-organisms
• Viruses, pathogens, germs in general
• Organic particles, heavily bio-degradable
• Organic compounds, inert, adsorpted to sludge flocs
• Heavy metals
• Micro-pollutants, pharmaceuticals, endocrine disrupters
Urban Water Systems
All non-degraded compounds extracted from wastewater are found in the sludge
12 Sludge treatment
Activated sludge plants
Hyperion, Playa del Rey, CA)
Primary aeration tank
Tertiary treatment
Involve some type of physicochemical treatment such as coagulation, filtration, activated carbon adsorbtion of organics and additional disinfectan
Volume reduction
Urban Water Systems page 25
• Thickening
• Dewatering
• If used in agriculture as fertiliser or compost
Elimination of pathogenic germs
Stabilisation of organic substances
• Gas production
• Reduction of dry content
• Improvement of dewatering
• Reduction of odour
Recycling of substances • Nutrients, fertiliser
• Humus
• Biogas 12 Sludge treatment
Overview
© PK, 2006 - page 26
Wastewater treatment
Urban Water Systems
Primary, secondary, tertiary sludge
Gujer (1999)
Thickening
Hygienisation
Stabilisation
Thickening
Dewatering
Drying
Incineration
Energy
Biogas
Agriculture
Disposal site
Construction industry
12 Sludge treatment
Atmosphere
Oxygenated systems
Cryogenic air separation facility, Hyperion, Playa del Rey, CA)
Typical steps in modern wastewater treatment
Flotation unit
© PK, 2006 - page 29
Urban Water Systems
12 Sludge treatment
Examples of naturally transmissible catabolic plasmids
Primary substrate
Toluene
Alkylbenzene sulfonate octane
Plasmid Size
(kb)
Host pWW0 (TOL) 117 Pseudomonas putida mt-2
ASL
OCT
Naphthalene Nah7
91.5 Pseudomonas testosroni
~500 P.oleovorans
83 P. Putida PpG7
Pseudomonas putida mt-2
Chromosomal gene encode ortho pathway : acetyl CoA and succinate
TOL plasmid encodes meta pathway : acetaldehide and pyruvic acid
TOL (pWW0) plasmid
The genes encoding catabolic enzymes : xyl genes
The Xyl genes : xyl ABC (upper) and xyl
XYZLEGFJKIH (lower/meta)
Xyl ABC
Encode degradation toluene and xylene to benzoate and metylbenzoates
Xyl XYZLEGFJKIH
Encodes degradation of benzoate and methylbenzoate to acetaldehyde and pyruvat
