OREANDA-NEWS. November 16, 2011. Animal bioindicators monitoring the treated water quality at South-West Wastewater Treatment Plant were replaced. Slender-clawed river crayfish set to work in wintertime instead of the Australian red-clawed ones.

The substitution of “workers” is caused by the change of wastewater temperature. In summer, the Australian red-clawed Cherax quadricarinatus monitored the quality of wastewater treatment. For them, the comfortable temperature range is 18 to 31оС (we are talking about the wastewater temperature).

As the cold weather came and wastewater temperature fell to 17оС, the thermophilic animals were replaced with slender-clawed crayfish. For them the optimal temperature should not exceed 22-230С.

The process of replacing crayfish is simple. Scientists take off the optic fibre sensor from one animal and fix it on the carapaces of others, clean the tank, place slender-clawed crayfish there and feed them. The Australian crayfish, whose shift is already finished this year, will wait for the next summer in a scientific laboratory.