Technical proposal for anaerobic digestion & biogas projects

Any biogas plant falls under ICPE classification 2781 (anaerobic digestion of non-hazardous waste). Depending on capacity, the installation requires declaration (under 30 t/d), registration (30-100 t/d) or full authorisation (over 100 t/d). The proposal must state the applicable regime and demonstrate compliance with setback distances, risk prevention (ATEX, fire), effluent management and nuisance control.

For biomethane injection, feed-in tariffs are set by decree and depend on production capacity and feedstock type. For CHP, the electricity purchase tariff is guaranteed for 20 years. The economic section must reference current tariffs and biogas production certificates (guarantees of origin).

Digestate must be managed in compliance with regulations. The spreading plan is mandatory, defining receiving plots, maximum doses, exclusion periods and analysis programme. The proposal must present the digestate valorisation strategy: direct spreading, phase separation, composting or drying.

Present: feedstock list with annual tonnages, biochemical methane potential (BMP) per substrate, overall mass balance (inputs, biogas produced, digestate), and supply security (contracts, transport distances, storage). A 15-20 year supply plan with alternatives is highly valued.

Detail the digester type (CSTR, plug flow, dry digestion), operating conditions (mesophilic 38°C or thermophilic 55°C), hydraulic retention time (HRT), organic loading rate, and associated equipment. Justify wet vs dry process based on feedstock characteristics.

The valorisation choice is structural. Present a techno-economic analysis comparing: grid proximity, heat offtake opportunities, applicable tariffs, investment and comparative profitability.

Biogas contains methane (55-65%) and hydrogen sulphide: present ATEX zoning, gas detectors, safety flare, ventilation, emergency response plan, and staff training. Odour management is often an explicit scoring criterion.