Effective stormwater treatment
with moving lamellae –
no external energy required

The Challenge

Rain­wa­ter car­ry­ing impu­ri­ties from paved and sealed sur­faces in built-up areas and drainage from roads lead to seri­ous pol­lu­tion of receiv­ing waters. Aside from acci­dents involv­ing haz­ardous mate­ri­als, this “nor­mal” con­t­a­m­i­na­tion is made up large­ly of sub­stances in the form of sus­pend­ed sol­id par­ti­cles which are the major cause of ongo­ing water pollution.

The Way

At around 70%, sus­pend­ed solids (< 200µm) make up the largest part of float­ing sub­stances. Most sus­pend­ed solids respond to set­tle­ment. A sim­ple sed­i­men­ta­tion treat­ment can con­tribute sig­nif­i­cant­ly to an effec­tive reduc­tion or com­plete avoid­ance of impu­ri­ties at the out­flow. Mod­ern waste­water treat­ment focuss­es on stormwa­ter set­tling tanks as the cen­tral treat­ment organ.

The instal­la­tion of tech­no­log­i­cal com­po­nents – lamel­lae – can improve the set­tle­ment per­for­mance of stormwa­ter sed­i­men­ta­tion basins con­sid­er­ably, reduc­ing con­struc­tion size and also sav­ing invest­ment costs.

The Solution

The HydroM.E.S.I. Par­ti­cle Sep­a­ra­tor is spe­cial­ly designed to deal with par­ti­cle-based water pol­lu­tion. Whilst in oper­a­tion the lamel­lae plates are sub­merged; the pol­lu­tant impu­ri­ties are bond­ed to the fine sus­pend­ed solids. These solids are set­tled to the floor of the tank as the untreat­ed water flows between diag­o­nal­ly-inclined lamel­lae plates. Free-float­ing light sub­stances, such as oil or hydro­car­bon com­pounds, are treat­ed by coa­les­cence. 

The HydroM.E.S.I. Par­ti­cle Sep­a­ra­tor is equipped with a flex­i­ble lamel­la struc­ture whose angle of incline is adjustable. On fill­ing, the ris­ing water lev­el moves the lamel­lae from the ver­ti­cal posi­tion into the pre-pro­grammed oper­a­tional angle, float-con­trolled and with no exter­nal ener­gy source. The dis­tance between the indi­vid­ual lamel­lae is vari­able and, if required, can be adjust­ed to increase puri­fy­ing effi­cien­cy after installation.

The water to be treat­ed flows through the sand and grit trap into the sep­a­ra­tion cham­ber where it ris­es through the diag­o­nal­ly-slant­i­ng lamel­lae from bot­tom to top, sep­a­rat­ing the sus­pend­ed par­ti­cles. Set­tled sub­stances accu­mu­late in the form of sludge on the tank floor. Float­ing and light mate­ri­als col­lect on the sur­face and are kept from flow­ing out of the sys­tem by a scum board. The treat­ed water flows out of the par­ti­cle sep­a­ra­tor through an open chan­nel. (Annu­al aver­age reten­tion of fine fil­ter­able sub­stances up to approx. 70% and up to 53% of these sub­stances < 63 µ)

After the HydroM.E.S.I. Par­ti­cle Sep­a­ra­tor is emp­tied, the lamel­lae return auto­mat­i­cal­ly to their ver­ti­cal posi­tion. Any par­tic­u­lates remain­ing on the sur­face of the lamel­lae fall down to the basin floor. A flush wave wash­es the set­tled impu­ri­ties on the basin floor into the sand and grit trap for dis­pos­al (suc­tion device, pumps, etc.).

On request the HydroM.E.S.I. Par­ti­cle Sep­a­ra­tor can be sup­plied with an inte­grat­ed clean­ing sys­tem, an auto-mat­ed sludge dis­pos­al unit and a fil­tra­tion unit. (Annu­al aver­age reten­tion of fine fil­ter­able sub­stances up to approx. 90% and up to approx. 80% of these sub­stances < 63 µ).

The Advantages:

• com­pact construction
• only slight head loss
• free of exter­nal energy
• mod­u­lar extension
• large reten­tion or set­tling sur­faces in a small area
• vari­able design or upgrad­ing to opti­mal eco­log­i­cal or eco­nom­ic limits