More than 50 000 peo­ple suf­fer­ing from kid­ney fail­ure in France require haemodial­y­sis or arti­fi­cial kid­ney treat­ment. As a nephrol­o­gist, Haf­sah Hachad has come to ques­tion the envi­ron­men­tal impact of cer­tain tech­niques, par­tic­u­lar­ly dial­y­sis, in terms of both car­bon foot­print and water consumption.

These are issues that she want­ed to explore in greater depth by start­ing a PhD the­sis at UTC in autumn 2022, fund­ed by the Insti­tute for Envi­ron­men­tal Tran­si­tion at the Sor­bonne Uni­ver­si­ty clus­ter. But before that — with the help of Cécile Legal­lais and Maryvonne Hour­mant from the SFNDT’s green nephrol­o­gy work­ing group — she had to spend a year estab­lish­ing the state of the art in the field in order to pro­pose “an orig­i­nal, rel­e­vant and coher­ent project, as well as prov­ing the con­cept”, she says. “We had to show that this project made sense and that it was of inter­est to nephrol­o­gists and dial­y­sis cen­tres alike”, she adds. Sup­port on the ground is essen­tial for a project like this.

As far as the car­bon foot­print is con­cerned, her field stud­ies in three dial­y­sis cen­tres proved to be in line with exist­ing lit­er­a­ture. “The car­bon foot­print is 9 tonnes per year for a haemodial­y­sis patient in a seri­ous case cen­tre. In com­par­i­son, the aver­age annu­al car­bon foot­print of a French per­son is esti­mat­ed at 9 tCO2. That’s 18 tCO2 per dial­y­sis patient per year. If we want to respect the Paris Agree­ment and lim­it the rise in tem­per­a­ture to below 2 degrees by the end of the cen­tu­ry, we need to reduce our green­house gas emis­sions, and in par­tic­u­lar to 2 tonnes of CO2 equiv­a­lent per year per inhab­i­tant by 2050”, she stresses.

Fur­ther­more, in a world where water scarci­ty will require rig­or­ous resource man­age­ment, the issue of water con­sump­tion in haemodial­y­sis is cru­cial. “Dur­ing each ses­sion, near­ly 400 litres of water are used to pro­duce the dial­y­sis flu­id. In the end, each patient, with three ses­sions a week, con­sumes 75 m³ a year. How­ev­er, pre-treat­ment of mains water in a reverse osmo­sis loop results in a large amount of waste (up to 250 litres per ses­sion), which is cur­rent­ly being wast­ed. With a view to con­serv­ing resources, this rel­a­tive­ly con­stant qual­i­ty water, which has nev­er been in con­tact with the patient, could be recy­cled for a vari­ety of pur­pos­es”, she explains.

With this PhD, Haf­sah Hachad hopes to find solu­tions to reduce the car­bon foot­print of dial­y­sis and recov­er the con­cen­trate for oth­er uses.