The removal and degradation of organic matter under controlled condition Primary treatment Secondary treatment Tertiary 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) 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 • • • 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 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 Gram negative bacteria : Zooglea, Pseudomonas, Alcaligenes, Achromobacter, Flavobacterium Gram positive : Corynebacterium, etc Fungi : Fusarium, Trisporon, Ascoidea It contains a high level of the organic nutrients phosphate and nitrate Nitrosomonas : oxidize ammonia to nitrite Nitrobacter : oxidize nitrite to nitrate Aerobic 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) 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 Acetogenesis CH4 methanogenesis In situ bioremediation: biostimulasi,bioaugmentasi, biosparging Ex situ biremediation Composting Landfarming Above-ground bioreactors Biopiles Note filamentous bacteria Note Vorticella and other protozoa L L0 L L L L Composition of sludge • 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 All non-degraded compounds extracted from wastewater are found in the sludge 12 Sludge treatment Urban Water Systems © PK, 2006 - page 21 Hyperion, Playa del Rey, CA) Involve some type of physicochemical treatment such as coagulation, filtration, activated carbon adsorbtion of organics and additional disinfectan Goals of sludge treatment Volume reduction • Thickening • Dewatering Elimination of pathogenic germs • If used in agriculture as fertiliser or compost Stabilisation of organic substances • • • • Recycling of substances • Nutrients, fertiliser • Humus • Biogas Gas production Reduction of dry content Improvement of dewatering Reduction of odour 12 Sludge treatment Urban Water Systems © PK, 2006 page 25 Overview Wastewater treatment Process water Primary, secondary, tertiary sludge Thickening Hygienisation Stabilisation Biogas Thickening Agriculture Dewatering Disposal site Drying Gujer (1999) Energy Construction industry Incineration 12 Sludge treatment Urban Water Systems © PK, 2006 page 26 Atmosphere Cryogenic air separation facility, Hyperion, Playa del Rey, CA) Flotation unit 12 Sludge treatment Urban Water Systems © PK, 2006 page 29 Primary substrate Plasmid Size (kb) Host Toluene pWW0 (TOL) 115 Pseudomonas putida mt-2 Alkylbenzene sulfonate ASL 91.5 Pseudomonas testosroni octane OCT ~500 P.oleovorans Naphthalene Nah7 83 P. Putida PpG7 Chromosomal gene encode ortho pathway : acetyl CoA and succinate TOL plasmid encodes meta pathway : acetaldehide and pyruvic acid The genes encoding catabolic enzymes : xyl genes The xyl genes : xylCAB (upper) and xyl XYZLEGFJKIH (lower/meta).....operon the host : capacity to degrade not only toluena but also m- and p- xylene, other benzena derivates Encode degradation toluene and xylene to benzoate and metylbenzoates Encodes degradation of benzoate and methylbenzoate to acetaldehyde and pyruvat Xyl R, xylS When a substrat enters the cell, it binds to the XylR protein to form a XylR-toluene complex (ex= toluen) The complex binds to promoter of the xylR operon to activating transcription of xylR...............activation the upper pathway genes Gene Enzyme xylA Xylene oxygenase xylB Benzyl alcohol dehydrogenase xylC Benzaldehyde dehydrogenase
