OREANDA-NEWS. February 9, 2012. Diagnostics of functional status of the Australian crayfish that worked at SWWTP during the summer and autumn is completed. The checkup found that the crayfish, which assessed the treated effluent quality for 5 months, are completely healthy. Australian red-clawed crayfish (Cherax quadricarinatus) started to work at South-West Wastewater Treatment Plant in July, 2011. In November, scientists from St.-Petersburg Research Center for Ecological Safety of Russian Academy of Science replaced these thermophilic crayfish with slender-clawed ones dwelling in the Neva River. The substitution of “workers” is caused by the change of wastewater temperature. For Australian crayfish, the comfortable temperature range is 18 to 31оС (we are talking about the wastewater temperature).

As the cold weather came and the wastewater temperature fell to 17оС, these thermophilic animals were replaced with slender-clawed crayfish. For them the optimal temperature should not exceed 22-23оС. The Australian crayfish were taken to a laboratory, where scientists examined the animals and carried out an original “health check” by assessing their physiological status. Recently, the animals successfully cast their shells and now are in a good form. In summer, when the warm weather comes, these crayfish wll be placed in aquaria at SWWTP again – they will substitute the slender-clawed ones that are working now, in the cold period.