Covered Lagoon Biodigesters PDF
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Uploaded by SmoothSweetPea
Mindanao State University
Arthur It. Tambong
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Summary
This presentation details covered lagoon biodigesters, focusing on design, information, standards, and construction steps for swine farms in the Philippines.
Full Transcript
COVERED LAGOON BIODIGESTERS Photographs courtesy of US Environmental Protection Agency and Methane to Markets partners around the world Arthur It. Tambong, M.Eng., FPSAE Professor III and Director, MSU-Affiliated Renewable Energy Center Mindanao State University – Main...
COVERED LAGOON BIODIGESTERS Photographs courtesy of US Environmental Protection Agency and Methane to Markets partners around the world Arthur It. Tambong, M.Eng., FPSAE Professor III and Director, MSU-Affiliated Renewable Energy Center Mindanao State University – Main Campus, Philippines [email protected], tel. +63 928-676-3258, www.ebytex.com Presentation Coverage Existing installations Definition and schematic diagram Typical farm layout with biodigester Most common problem Digester volume sizing Digester design values and information Design standards Construction steps Covered Lagoon Biodigester in Sta. Monica, Mexico Covered Lagoon Biodigester in Haidong, China Covered Lagoon Biodigester in Gen.Trias, Cavite, Philippines What is a Covered Lagoon Biodigester? It is a lagoon for fermenting diluted manure covered and lined with geomembrane to produce biogas while greatly reducing methane and carbon dioxide air emissions. Schematic Diagram Common Problem in Covered Lagoon Biodigesters: Whaling - biogas generation under the lining due to geomembrane leakage Prevention: Quality construction Underdrain system V-shaped bottom Gas venting system How Big Should Be Your Digester? Volume is based on Volatile Solids Loading Rate (VSLR) and the minimum design Hydraulic Retention Time (HRT). Minimum Operationg Volume based on VSLR: VSLR (kg/day) VVSLR (m3) = ──────────────────────── Maximum Design VSLR (kg/m3-day) Minimum Operationg Volume based on HRT: VHRT (m3) = Influent Flow Rate (m3/day) x Minimum Design HRT (days) Design Operating Volume is the bigger value between VVSLR and VHRT Digester Volume Design Information for Swine Farm in the Philippines Maximum Design VSLR ≈ 0.192 kg/m3-day at 32 ºC ave. Change in VSLR ≈ -0.0025 kg/m3-day per ºC drop Volatile Solids ≈ 0.1-1.04 kg/head-day, max. if lactating Hydraulic Retention Time (HRT) ≈ 35 days at 32 ºC ave. Change in HRT ≈ +1 day per 2 ºC drop Manure Vol. ≈ 0.001-0.01 m3/head-day, max if lactating Water Inflow ≈ 0.004-0.04 m3/head-day, max if lactating Influent flow rate = Manure Vol./day + Water inflow/day Max. VSLR & min. HRT vary with temperature Covered Lagoon Biodigester Design Standards (US Standards Applicable in the Philippines) Minimum design operating volume: Volatile solids loading rate & Min. hydraulic retention time (HRT), whichever is higher Min. Operating depth: 12 ft for over half of floor area Min. digester freeboard: 2 ft above water surface Interior slopes: As steep as permitted by soil properties and construction techniques Maximum length to width ratio: 4:1 Maximum influent solids content:
