Treatment and Disposal of Sludge stabilization thickening conditioning dewater drying disposal

Thickening ‧Suatu proses untuk menaikkan kandungan solid (dari 0.5 – 1.5 % menjadi 2 – 3 %) didalam sludge dengan mengurangi kandungan air nya. Metoda penurunan kadar air dapat dilakukan dengan cara : - Pengendapan secara gravitasi. - Pengapungan dengan pelarutan udara.

Gravity thickener

Stabilization ‧Solids and biosolids are stabilized to : - reduce pathogens, - eliminate offensive odors,

DEWATERING BELT – FILTER PRESS SLUDGE DRYING BED SLUDGE LAGOON

BELT – FILTER PRESS

Belt filter press

SLUDGE STABILIZATION

SLUDGE – DRYING BED Umumnya dipergunakan untuk pengeringan sludge dari Small – Medium IPAL. Pengeringan terjadi karena penguapan alamiah dan infiltrasi. Susunan Media : Gravel dan Sand dengan ketinggian dry – sludge yaitu (20 – 30) cm.

Susunan media Ukuran Media Ketinggian media (cm) Fine Sand 15 Coarse sand 7,5 Fine gravel Medium Gravel Coarse gravel 7,5 - 15

Desain Kriteria Jenis Sludge Population Equivalent (m2/orang) Solid Loading Rate (SLR) (kg dry solid/(m2.tahun) Primary Digested 0,1 120 – 150 Primary & TF Sludge digested 0,12 - 0,16 90 – 120 Primary & Activated Sludge digested 0,16 – 0,23 60 – 100 Primary & Chemically Precipated digested 0,19 – 0,23 100 - 160

Drying bed

Drying bed

Alkaline stabilization ‧Lime is usually used to raise pH to 12 or higher, so that microbial activities are retarded or inactivated. ‧Major advantage lies in the soil-like product with substantially reduced pathogens. However, solid contents are increased.

Anaerobic stabilization ‧The oldest and the most commonly used one owing to energy efficiency and beneficial use of digested biosolids. ‧Three reactions: hydrolysis, acidogenesis, and methanogenesis. ‧Important factors include: HRT, temp, alkalinity, pH, toxic compounds, and bioavailability of nutrients.

Anaerobic Fermentation & Oxidation Utilized mostly in treating sludge and the pretreatment of high-strength organic wastes. Becoming more common for dilute waste streams. Advantages of lower biomass yield and energy (CH4) recovery. Thermophilic fermentation processes under development.

Process Hydrolysis: Particulate materials are converted to soluble compounds and simpler monomers. Fermentation (acidogenesis): Fatty acids, amino acids, and etc are degraded further to acetate, CO2, H2, propionate and butyrate. Methanogenesis: Acetate is converted to CH4 and CO2; and H2 and CO2 are converted to CH4.

C and H flow in anaerobic process

Anaerobic Digestion - continued Methane Production

Anaerobic digesters

Waffle Bottom Anaerobic Digester Plan view Section view 25

Egg Shape Digester Deer Island Sewage Treatment Plant Massachusetts Water Resources Authority (MWRA) (140 ft tall and 3 million gallons of sludge) 26

Egg-shaped digester

Egg Shape Anaerobic Digester 28

Egg Shape Anaerobic Digesters 29

Egg Shape Anaerobic Digesters 30

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