Engineered disposal of residual waste — sanitary landfill design (siting, liner, leachate collection, gas collection, daily cover, capping), operating practices (compaction, weighing, record-keeping), groundwater + air monitoring, post-closure care, comparison with legacy dumpsites (chapter 12), MSW Rules 2016 + CPCB compliance.
Size a sanitary landfill given residual waste TPD (post-processing diversion), design life, compacted bulk density, daily cover allowance. Output is gross landfill volume + footprint area at typical depth. Per MSW Rules 2016: minimum 20-year design life.
Sanitary landfill is the engineered disposal route for residual waste that can't be composted, biomethanated, recycled, or co-processed. Per MSW Rules 2016, it's the only legal disposal method — open dumpsites (chapter 12 covers their remediation) are formally banned.
The design must achieve: (1) hydraulic isolation of waste from groundwater (HDPE geomembrane 1.5-2 mm + compacted clay 600-900 mm = permeability ≤ 1×10⁻⁹ m/s), (2) leachate collection + treatment (perforated HDPE pipes + treatment to discharge norms), (3) landfill gas collection + flaring or utilisation, (4) daily + intermediate + final cover, (5) monitoring (groundwater + air + settlement), (6) 30-year post-closure care.
Siting is the politically hardest part. NIMBY response is intense — nobody wants a landfill nearby. Most Indian cities now site landfills 30-50 km outside city — adding significantly to collection + transport cost (chapter 3). Site selection must comply with MSW Rules 2016 Schedule I: ≥ 200 m from water bodies, ≥ 500 m from residential, ≥ 10 km from airport (per DGCA), ≥ 2 m above seasonal high groundwater, geological + soil suitability, access road, 20-25 year volume capacity.
Liner system is non-negotiable. HDPE geomembrane (primary barrier, 1.5-2 mm thick) over compacted clay or geosynthetic clay liner (secondary barrier, 600-900 mm thick) achieves combined permeability ≤ 1×10⁻⁹ m/s. Without proper liner, groundwater contamination is guaranteed within 5-10 years — and remediation is essentially impossible.
Leachate is the operational headache. 5-15 % of rainfall reaches leachate after compacted-cover deflection — for a 5-hectare landfill in 1500 mm/year rainfall, that's 75-225 m³/day. Treatment combines biological (aerated lagoon, MBR) with physical-chemical (coagulation, RO, evaporation). Treatment cost ₹150-400/m³.
Landfill gas (LFG): 50/50 methane/CO2, generation peaks ~10 years post-closure + decays over 20-30 years. Total: 100-200 m³ per tonne MSW (USEPA model). Either flare (small landfills, uneconomic to use) OR generate electricity via gas engine OR upgrade to CBG (same use as biomethanation, chapter 6).
Operations: weighbridge for accurate input data, tracked compactor (Caterpillar 826, Bomag) for 700-900 kg/m³ density, daily cover application, fire-fighting + dust suppression + vector control, perimeter fencing, vehicle wash. Cellular development pattern is modern best practice — only one cell open at a time, cap as soon as full.
Monitoring: ≥ 3 wells (one upgradient + 2+ downgradient), quarterly during operation, semi-annual for 30 years post-closure. Tests: pH, BOD, COD, heavy metals (Cd, Cr, Pb, Hg, Ni, As), nitrate, chloride, TDS, organics. CPCB + SPCB inspections.
Cost reality (2026): sanitary landfill capex ₹3-8 crore per hectare for liner + collection systems; total project ₹50-300 crore for typical city landfill (10-30 ha). O&M ₹500-1500/tonne disposed. Post-closure trust fund ₹50-200/tonne accumulated during operation.
Where this chapter sits: sanitary landfill is the disposal endpoint for the 5-15 % residue that all upstream processing produces. Done well, it's environmentally safe + lasts 20-25 years; done poorly, it becomes the next legacy dumpsite (chapter 12) requiring expensive remediation. The engineering is mature; the failure modes are operational + political.