Thetford’s Biodegradable Tissue Digester is specially formulated to dissolve tissue build-up in a mobile septic tank. The 100% biodegradable liquid works with both black and grey water tanks, on RVs or boats. The Tissue Digester prevents build-ups and restores the operation in the drain lines and is safe for all waste treatment systems. The digester breaks up tissue-causing clogs and keeps drain lines clean and flowing free. It is specially formulated to prevents build-ups on tank walls and drain lines and is safe for all waste treatment systems.