Composting makes bioenergy sustainable
and opens high-value markets to residuals from anaerobic digestion
Modern landfill or incinerator-type waste-to-energy (WTE) technologies offer vast improvements over old incinerators and landfills. But unlike bioenergy production, burning or burying biodegradable waste has a fatal flaw — it destroys a valuable resource in the process. Burying organic matter does not complete the natural soil cycle. Compost use does.
Bioenergy and biofuel production through anaerobic digestion (AD) uses organic waste as a raw material for energy. But AD offers the opportunity to capture the resulting waste stream — known as digestate, sludge or effluent — for composting. When the compost is returned to the soil, a sustainable, renewable recycling loop is created.
Energy extraction does not devalue composting feedstocks
Energy extraction through digestion does not destroy the inherent composting value of organic waste for use as composting feedstocks. Plants don’t need the energy from biodegradable waste. Their energy source is the sun.
Composting digestate increases market value
Traditionally, digestate has been landfilled or applied to farmland. But composting opens new markets for this valuable resource. When used as a feedstock in the production of high-quality compost, the residuals of bioenergy production can also be used in urban areas to enrich and improve soil quality for parklands, sports fields, suburban lawns, etc. Better soils reduce the need for chemical fertilizers and hold moisture, conserving water and reducing stormwater runoff.
Composting digestate does two things:
- Improves economic viability for AD/bioenergy operations through the sale of compost to high-value markets like landscaping, sports turf and erosion control; and
- Makes the entire operation more sustainable. Compost products sold in the region grow new raw materials for agribusiness and industry. Eventually, the residues of these materials find their way back to the AD/composting facility as municipal, agricultural, or industrial wastes, closing the recycling loop.
McGill Environmental Systems, with over 25 years of experience in building and operating industrial composting facilities, offers composting augmentation for AD operations through retrofit of existing plants, add-on composting modules or new dual-technology facilities.
This systems approach to bioenergy production delivers significant cost savings over separate digestion and composting facilities. When used to capture and recycle all organics in a region (including biosolids), dual-technology systems can save millions of dollars and boost revenues when compared to stand-alone operations.
In addition to design, permitting, construction and operation, McGill’s turnkey services include:
- Feedstock sourcing and transportation
- Pre-treatment options like dewatering and biological sludge drying
- Power/fuel generation
- Product development and compost marketing
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