Control of sludge processes

Gea varipond stands for “vari­able pond depth” while the decanter cen­trifuge is run­ning. In waste­water treat­ment plants, a pre­cise, reli­able process flow must be ensured, includ­ing in wide­ly vary­ing con­di­tions. Such process­es include dewa­ter­ing and thick­en­ing of pri­ma­ry and sec­ondary sludge. The varipond adjusts to chang­ing require­ments at light­ning speed; its vari­able pond depth ensures solids are dis­charged at a sta­ble rate while the decanter is run­ning. Opti­cal sen­sors mea­sure the sol­id con­tent of thick­ened sludge and com­pare this with the con­fig­ured set point, while the con­trol sys­tem keeps the con­cen­tra­tion con­stant – with every­thing done auto­mat­i­cal­ly. This enables unsu­per­vised oper­a­tion even overnight and at weekends.

How it works

The point where the clar­i­fied liq­uid is dis­charged from the decanter bowl fea­tures an axi­al­ly adjustable throt­tle disc which deter­mines the width of the out­let aper­ture. A small gap means greater resis­tance, while a larg­er gap allows low­er water dis­charge and a high­er liq­uid lev­el. Intel­li­gent sen­sor tech­nol­o­gy auto­mat­i­cal­ly adjusts the aper­ture width accord­ing to the desired liq­uid lev­el in the decanter bowl by mov­ing the throt­tle disc into the opti­mal posi­tion while the machine is running.

Reduces decanter energy consumption

The ener­gy con­sump­tion of a decanter cen­trifuge is deter­mined, among oth­er fac­tors, by the pow­er required to dis­charge the clar­i­fied liq­uid. This can rep­re­sent up to 50% of the decanter’s over­all ener­gy con­sump­tion. In order to achieve opti­mal sep­a­ra­tion per­for­mance when dewa­ter­ing and thick­en­ing, spe­cif­ic G‑values are required with­in a defined range, depend­ing on the sludge char­ac­ter­is­tics and flow vol­ume. This means that con­tin­u­ous­ly main­tain­ing the max­i­mum G‑value is often not nec­es­sary: a spe­cial con­trol cir­cuit in the varipond uses a sen­sor to iden­ti­fy unnec­es­sar­i­ly high bowl speeds and opti­mizes them by con­stant­ly main­tain­ing the required dis­charge con­cen­tra­tion. The rotor geom­e­try also pro­vides addi­tion­al ener­gy sav­ings. The design of the bowls in the Gea deep-pond design ensures opti­mized flow behav­ior and enhanced clar­i­fi­ca­tion effect, and means less ener­gy is required to dis­charge the prod­uct. In short, this means that ener­gy con­sump­tion can be reduced by up to 30%.