Puzzle Chuyển Đổi Chất Thải Thành Năng Lượng

Waste = fuel: turn trash into electricity! Waste-to-Energy (WTE) technologies: (1) Incineration (burn MSW municipal solid waste 850-1000°C, heat boils water → steam drives turbines generate electricity 550-750 kWh/ton waste!), (2) Gasification (heat waste limited oxygen → syngas synthetic gas H2/CO/CH4 burn generators or chemical feedstock!), (3) Anaerobic digestion (bacteria break organic waste oxygen-free → biogas 60% methane burn or upgrade biomethane grid!), (4) Pyrolysis (heat without oxygen → bio-oil, syngas, biochar), (5) Landfill gas capture (methane from decomposition wells collect burn generators). Efficiency: modern incinerators 25-30% electrical efficiency (rest heat steam district heating cogeneration 80%+ total!), gasification 35-40% potential.

Emissions control critical: (1) Scrubbers (remove acid gases SO2, HCl), (2) Bag filters (capture particulates PM2.5 99.9%+!), (3) Activated carbon (adsorb dioxins, mercury heavy metals), (4) SCR/SNCR (reduce NOx nitrogen oxides). Ash management: bottom ash 20-25% weight (inert, use roads construction!), fly ash 2-5% (toxic heavy metals stabilize landfill!). Economics: capex $5M-10M per MW (500-ton/day plant $150-300M!), revenue electricity sales $0.08-0.15/kWh, tipping fees waste generators $50-100/ton.

Benefits: (1) Landfill diversion (reduce space 90% volume!), (2) Energy recovery (renewable RECs renewable energy credits!), (3) Pathogen destruction (high temps sterilize medical waste!). Controversies: (1) Emissions (dioxins, heavy metals IF poor controls!), (2) Discourage recycling (need steady waste feedstock!), (3) Costs (expensive vs. landfills BUT externalities!). Real plants: Spittelau Vienna (district heating, Hundertwasser art facade!), Shenzhen China (world largest 5000 tons/day!), Singapore 4 plants (incinerate 40%+ waste land-scarce!).

Vietnam context: Hanoi Nam Son landfill crisis (overflow!), HCMC pilots (Phuoc Hiep, Can Tho plants), challenges public opposition NIMBY, high costs, limited expertise. Future: plasma gasification (ultra-high temps 3000°C+ vitrify ash!), carbon capture (WTE plants bioenergy CCS net-negative emissions?!). Solve waste + energy circular!