Toilet Sludge or Biofilm

Stagnant or slow-moving water environments with high organic matter, such as toilet tanks, pipes, and drains.

Decomposing organic matter, minerals (like iron and manganese), and nitrogenous waste.

Forms a 'biofilm' which is a collective of microorganisms that stick to each other and surfaces via a slimy extracellular matrix.

Generally non-toxic but may cause allergic reactions or indicate poor sanitation; can clog pipes and create foul odors.