Hi Aruna, You can assume ...

Hi Aruna, You can assume suitable overflow rate based on the characteristics of the water/wastewater. The normal range is 24-36 m3/day/m2. You can divide your flow rate by this overflow rate to get the plan area of your lamella clarifier. You can assume depth of clarifier in the range of 2 to 3 m. Include some allowance for sludge storage. The lamela tubes should be fitted in the tank with some inclination. They will provide more surface area for settlement of suspended solids and remove the suspended solids efficiently. A company Prachi Services Inc has developed softwares for a) Design of water treatment plant b) Design of sewage/effluent treatment plant c) Design of advanced wastewater treatment plant ..etc. You can visit their website www.worldenviro.com  if you want to purchase one.