SDSai Dharshan
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CiiA 2026 · Reworked · In progress

Drone-Based Landfill Survey System

An independent drone survey system that tells a city how much legacy waste has actually left a dumpsite, with an error range. It separates real removal from waste that was only moved around inside the site, and flags underground fire hotspots during the flight.

DronesPhotogrammetryComputer visionThermal imagingEdge AIPython
Origin
Reworked CiiA 2026 entry
Built for
Municipal corporations & monitoring committees
Case site
Kodungaiyur, Chennai
Status
Phase 1 · campus validation
Placeholder: drone survey over a dumpsite

01 · Why I reworked it

What changed

Classifying individual waste items from 30–60 m altitude is hard, rarely accurate, and nobody pays for it. Payment verification and fire risk are where the money and the safety risk are, so I rebuilt the system around those.

Original CiiA ideaReworked system
Classify individual waste items from the airMap the site into material zones: mound, windrow, stockpile, soil-like fines, cleared ground, leachate, smouldering area
General “landfill monitoring” with no clear buyerA named user: the municipal corporation and its project monitoring committee, who certify contractor payments
One volume number per surveyVolume change with a confidence interval, converted to tonnes with the uncertainty carried through
Thermal imaging as a demo featureHotspot tracking across flights, flagged onboard so the output is “check grid C4 now”, not a report next week

02 · The problem

Problem

National scale

2,421legacy dumpsites (2024 count), over 14,822 acres
2,211 lakh tof legacy waste on those sites
3.66 crore tremediated across India, Jan–Dec 2025
DRAPNov 2025 programme pushing the remaining sites in mission mode

Swachh Bharat Mission-Urban 2.0 (launched October 2021) funds the clearing of legacy dumpsites. Cities report progress on the SBM-U portal, and that progress drives funding and rankings, so every reported tonne should be verifiable.

Local case: Kodungaiyur, Chennai

66.52 lakh tlegacy waste identified, spread across 252 of 342.91 acres
₹641 crorebiomining contract, six packages, three contractors (Feb 2024)
₹963.29 / tpaid per tonne removed
26.50 lakh tlatest reported removal

Anna University is the Project Monitoring Committee that supervises and certifies the contractors’ work. The site still takes in about 3,000 tonnes of fresh waste a day, and work slows or stops during the northeast monsoon.

What that means in money

≈ ₹6.4 crorethe cost of a 1% measurement error on 66.52 lakh t (66,520 t × ₹963.29)
≈ ₹385 crorestill to be certified for the remaining 40.02 lakh t

The specific gaps

01Removal vs relocation

Contractors constantly dig, windrow and stockpile. A height drop in one area may just reappear as a stockpile elsewhere on the site.

02Fresh waste masks progress

New dumping on the same ground adds volume while legacy waste is removed, so a single net number hides both.

03No error bars

Most drone volume reports give one figure. A payment decision needs to know whether it is ±1% or ±8%.

04Fires are found late

Subsurface smouldering can spread undetected before smoke appears, and is far harder to put out than a surface fire.

03 · Who it’s for

Users

Primary user

The municipal corporation (e.g. Greater Chennai Corporation) and its project monitoring committee (e.g. Anna University at Kodungaiyur).

Secondary users

Contractors, to support their own claims; fire services; state pollution control boards.

Each survey answers

  1. How many cubic metres and tonnes left the site since the last survey, and with what confidence range?
  2. How much was only moved within the site, and how much fresh waste was added?
  3. Where are the thermal hotspots, and are any of them growing?
  4. Are any slopes deforming fast enough to be a collapse risk?

04 · System architecture

System

In flight

  • RGB camera with RTK GNSS
  • Radiometric thermal camera
  • Optional: methane TDLAS sensor
  • Fixed ground control points and checkpoints, surveyed once

Onboard (Jetson-class)

  • Image geotagging and coverage check
  • Live hotspot detection and alert to the ground crew
  • CH₄ readings logged with position

Ground / cloud

  1. SfM photogrammetry → point cloud, DEM, orthomosaic, thermal ortho
  2. DEM-of-difference with uncertainty
  3. Material-zone segmentation (ML)
  4. Volume → tonnage (Monte Carlo)
  5. Hotspot tracking across surveys
  6. Survey report + web dashboard

Hardware

  • Mapping quadcopter carrying an RGB camera and a small radiometric thermal camera; RTK or PPK positioning strongly preferred
  • Permanent ground markers around the site edge, outside the working area, plus independent checkpoints for accuracy testing
  • NVIDIA Jetson-class module for in-flight hotspot detection
  • Later: downward-pointing open-path TDLAS methane sensor

Software

  • WebODM / OpenDroneMap for photogrammetry (Agisoft Metashape if available)
  • CloudCompare (M3C2) and Python (PDAL, rasterio, NumPy) for point clouds and change detection
  • PyTorch, with a U-Net or SegFormer-style model, for segmentation
  • Leaflet web map for the dashboard
Placeholder: mapping drone with RGB and thermal payload
Survey drone and payload.

Flight plan, every survey

  • Same flight lines, altitude, overlap (≥75% front, ≥65% side) and time of day, so surveys are comparable
  • RGB mapping flight by day; thermal flight at dawn or night, when solar heating is lowest and subsurface heat stands out
  • Monthly for payment verification; weekly thermal passes in the dry, fire-prone months

05 · How it works

Modules

Core

01Removal verification with uncertainty

  1. Build a DEM for each survey from the point cloud.
  2. Compute the DEM of Difference per grid cell: DoD = DEM(t₂) − DEM(t₁)
  3. Estimate each survey’s vertical error from the checkpoints and combine them: σ_DoD = √(σ₁² + σ₂²)
  4. Apply a level of detection, LoD95 = 1.96 × σ_DoD. Smaller changes are treated as noise.
  5. Use spatially varying uncertainty: steep, rough or poorly covered cells get bigger error bars than flat cleared ground (after Las2DoD and James et al. 2017).
  6. Sum cut and fill separately to get removed and added volume, each with a confidence interval.

Volume to tonnage. Payment is per tonne, but drones measure volume. A density range (from weighbridge records or core samples) and the DEM error run together through a Monte Carlo simulation, so the output reads like:

41,200 t removed · 95% interval 38,900–43,600 t
Example of the output format

Why this is the contribution. Drone volume surveys of landfills are already common. Erosion and river researchers routinely report volume change with propagated uncertainty; bringing that discipline to payment verification on an active waste site is the new part.

Placeholder: cut and fill change map with cells below the level of detection greyed out
Cut/fill change map; cells below the level of detection are greyed out.

Separating removal from relocation

02Material-zone segmentation

Classes: legacy mound · excavation face · windrow · stockpile (RDF / inert / fine soil-like material) · fresh waste · cleared ground · leachate pond · smouldering or burnt area · vegetation · vehicles and machinery (masked out).

  • Volume lost from mound cells and gained in stockpile or windrow cells is relocation, not removal.
  • Volume gained in fresh-waste cells is new dumping, reported separately.
  • Only material that leaves the site, or volume loss not balanced by gains elsewhere, counts toward removal.

Data: my own labelled orthomosaic tiles (starting with a few hundred), with height, slope and roughness from the DEM as extra input channels. Public aerial dumpsite datasets (AerialWaste, Roboflow) help with pretraining but don’t map landfill interiors.

Placeholder: segmentation map of material zones across the dumpsite
Material-zone map over the orthomosaic.

Fire risk

03Thermal hotspot tracking

  • Temperatures from a radiometric thermal camera are projected onto the 3D model, giving a “4D” model (X, Y, Z, temperature). A study at the Meruelo landfill in Spain did this with about 1.6 °C accuracy and found hot areas later confirmed on site.
  • Readings are corrected for emissivity and time of day: plastic, soil and wet surfaces read differently at the same temperature.
  • A surface hotspot shows heat near the surface, not depth. The output is a list of places to check with probes, not a diagnosis.
  • Each hotspot is tracked across flights (area, peak temperature, growth). Growth is the real warning sign.
  • The Jetson runs an anomaly detector during the flight and sends grid references to the ground crew immediately.
Placeholder: thermal orthomosaic with flagged hotspots
Thermal orthomosaic with flagged hotspots.

Optional

04Slope deformation alerts

Steep waste mounds can fail, especially after heavy rain; the 2017 Ghazipur landfill collapse in Delhi is the well-known Indian example. Repeat surveys already produce the data needed.

  • Compare point clouds with M3C2 to detect slope movement between flights. A 2024 study on a Polish landfill reported about ±2.3 cm mean vertical displacement error.
  • Flag cells on steep slopes where movement exceeds the level of detection, especially after monsoon rain.
Placeholder: slope deformation map between two surveys
Slope movement between two surveys.

06 · Deliverable per flight

Survey report

  • Headline: removed tonnage since the last survey with a 95% interval; cumulative total vs the contractor’s claim
  • Change map: cut/fill by grid cell, with cells below the level of detection greyed out
  • Zone map: relocation vs removal vs fresh dumping
  • Hotspot table: grid ref, area, peak temperature, trend (new / stable / growing)
  • Slope alerts, if Module 4 is on
  • Quality section: checkpoint errors, coverage gaps, weather, anything that widens the error bars

07 · Validation plan

Roadmap

  1. Phase 1 · Now – mid Nov 2026

    Campus test: survey a sand/soil pile, remove a known volume (counted truckloads), survey again.

    EvidenceDoes the DoD interval contain the true removed volume?

  2. Phase 2 · Mid Nov – Dec 2026

    Label orthomosaic tiles and train the zone segmentation model.

    EvidencePer-class accuracy; relocation vs removal on a staged test.

  3. Phase 3 · Dec 2026 – Jan 2027

    Request past survey data or a supervised test flight via GCC and the Anna University PMC.

    EvidenceComparison with the official certified figures.

  4. Phase 4 · Exchange semester

    Thermal module and onboard Jetson hotspot flagging, as an ML / edge-AI course project.

    EvidenceIn-flight alert latency; hotspot repeatability.

Readiness path

TRL 4Pipeline validated

On the campus pile (Phase 1).

TRL 5Components validated

On real dumpsite data (Phase 3).

TRL 6System demonstrated

The integrated system flown over an actual dumpsite and compared against official figures.

08 · What already exists

Prior art

Drone volume surveys

Widespread commercially for dumpsites and stockpiles. Volume measurement itself is not new.

UAV thermal surveys of landfill fires

Used by regulators (e.g. Washington State Department of Ecology, 2023–24) and in research on 3D/4D thermal models.

UAV methane surveys

The UK Environment Agency trialled downward-pointing TDLAS drones in place of walkover surveys, with promising results, though walkovers still pinpointed some sources better.

Uncertainty-aware change detection

Mature in geomorphology: the GCD toolbox, M3C2-PM, Las2DoD.

What’s new here is the combination for this specific user: uncertainty-bounded removal figures for payment certification, relocation and fresh-waste separation through zone segmentation, and in-flight hotspot alerts, on Indian legacy dumpsites.

09 · Constraints & risks

Risks

Drone Rules 2021 / Digital Sky

Check the site’s airspace zone before any flight; register the drone; a remote pilot certificate is needed above the nano category.

Site permission

Written approval from the municipal corporation, and coordination with contractors’ machinery.

Safety

Methane, unstable slopes and smouldering ground: nobody walks on the mound to place markers, and ground control stays on stable edges.

Monsoon

Flights and biomining both pause; the gap goes to processing and model training.

RiskMitigation
Waste density varies widely, so tonnage error dominatesUse weighbridge data if shared; report density as a range, not a single value
Machinery and dust create false changeMask vehicles; fly at consistent times; flag low-quality cells
Thermal readings affected by sun and emissivityDawn/night flights; emissivity correction; ground probe confirmation
No access to a real siteCampus validation first; request archived survey data instead of flights
Contractor or authority reluctancePosition it as a neutral tool that also protects honest contractors from disputes

10 · References

Sources

  1. DT Next — Over 52 lakh MT of legacy waste removed from Perungudi, Kodungaiyur. dtnext.in
  2. DT Next — GCC to raise ₹205 crore via green bond for Kodungaiyur bio-mining (₹963.29/MT). dtnext.in
  3. DT Next — Anna University as Project Monitoring Committee. dtnext.in
  4. DT Next — Fresh waste inflow and monsoon pause at Kodungaiyur. dtnext.in
  5. Business Standard — SBM-U 2.0 legacy site totals (2024). business-standard.com
  6. Shankar IAS (PIB summary, Sept 2026) — Reclaiming the land beneath the waste. shankariasparliament.com
  7. Sedano-Cibrián et al. (2023), 4D models with UAV photogrammetry for landfill thermal control, Applied Sciences. doaj.org
  8. Nazari et al. (2020), Satellite remote sensing of elevated landfill temperatures. doaj.org
  9. Washington Dept. of Ecology — UAS thermal survey of landfill fire. ecology.wa.gov
  10. UK Environment Agency — Drone flyover surveys for methane at landfills. gov.uk
  11. Pasternak et al. (2024), UAV photogrammetry for geometric changes of reclaimed landfills, Sensors. mdpi.com
  12. Bailey et al. (2022), Las2DoD — change detection with spatially varied uncertainty. mdpi.com
  13. James, Robson & Smith (2017), 3-D uncertainty-based change detection with SfM. discovery.ucl.ac.uk
  14. NCSU UAS course — DoD error propagation and LoD95. ncsu-geoforall-lab.github.io