Material Pathways

Follow materials, controls and possible destinations.

Sludge, biosolids, digestate, char and ash are different materials. Choose one and an objective to see plausible options, what each needs, and which gates remain open. An advertised technology is not regulatory permission or validated performance at an actual facility.

1. Select a material

Anaerobic digestate. The residual material after anaerobic digestion, liquid or dewatered.

Boundary: Not biosolids by default; classification depends on origin and local rules.

2. Choose an objective

3. Plausible options

No option is ranked or recommended. Choosing one would need site data and verified criteria. Select up to three to compare.

7 options mapped for Anaerobic digestate

Dewatering and drying

Established practice. Suitability depends on the site.

Required inputs: Material identity, current dry solids, available heat.
Likely outputs: Lower-mass material at higher dry solids.
Residuals: Separated water needing treatment; possible odour and dust.
Controlling unknowns: Energy source and cost; effect on later product eligibility.
Gates: Dry-solids target agreed; energy balance reviewed.

Atlas:E N Evidence

Compare

Pyrolysis and thermal processing

Research and engineering question. No performance claimed.

Required inputs: Dried feedstock, defined process envelope, emission controls.
Likely outputs: Char, gas, condensate.
Residuals: Ash, condensate and air-control residues, all needing accounting.
Controlling unknowns: Contaminant partitioning across every output; measurement boundaries.
Gates: Full input-output mass balance; third-party testing; regulatory permission.

Atlas:G H O Evidence

Compare

Nutrient recovery from side-streams

Several routes exist. Fit depends on stream composition.

Required inputs: Stream nutrient concentrations and variability.
Likely outputs: Concentrated nutrient product.
Residuals: Treated liquid; possible co-recovered contaminants.
Controlling unknowns: Plant availability of the recovered product; contaminant carry-over.
Gates: Product analysis; availability testing.

Atlas:I F J Evidence

Compare

Product qualification and agronomic trials

Protocol stage. No trial is claimed to have been performed.

Required inputs: Batch records, product tests, site selection.
Likely outputs: Evidence on release, soil function and crop response.
Residuals: Unused or failed batches to be managed.
Controlling unknowns: Treatment rates, replication, power and site approval need independent scientist input.
Gates: Product QA passed; permission to apply; ethics of site and landholder consent.

Atlas:J K M Evidence

Compare

Receiving-site assessment

Method framework. Applies to any proposed use.

Required inputs: Soil and water data, product analyses, crop and land-use plans.
Likely outputs: A documented view of whether a use is plausible and what must be monitored.
Residuals: Unresolved risks recorded explicitly.
Controlling unknowns: Long-term accumulation and off-site transfer.
Gates: Permitted use confirmed; monitoring plan agreed.

Atlas:K L M Evidence

Compare

Whole-process contaminant accounting

Evidence need. Required before any contaminant claim.

Required inputs: Feedstock speciation, sampling plan, analytical methods.
Likely outputs: Mass balance across all outputs with stated uncertainty.
Residuals: Contaminated streams and media needing controlled disposal.
Controlling unknowns: Sampling representativeness; analytical limits.
Gates: Independent testing; check against current national guidance.

Atlas:H A R Evidence

Compare

Carbon accounting study

Method question. Carbon retention is not an issued credit.

Required inputs: System boundary, emissions factors, stability evidence.
Likely outputs: A bounded estimate with assumptions.
Residuals: Unquantified emissions outside the boundary.
Controlling unknowns: Permanence of retained carbon; applicable formal methodology.
Gates: Recognised method selected; evidence of stability.

Atlas:O G R Evidence

Compare

Gates between anaerobic digestate and a verified outcome

01Characterise origin, dry solids and contaminant profileNot evidenced
02Select an evidence-supported conditioning or recovery routeNot evidenced
03Product QA and nutrient-release assessmentNot evidenced
04Controlled agricultural testsNot evidenced
05Lawful application and multi-year outcomesNot evidenced

Every gate is shown as missing because no site data has been entered. A missing gate is not a failure, but it blocks any claim of success.