Design for a water treatment plant:

1. Produce as individuals a single tab Excel spreadsheet which shows a rough initial design for a water treatment plant taking 15MLD of water with 100 mg/l SS from a lake at 750mAOD, passing it through settlement tanks on to pressure sand filters, and from there into a chlorine contact tank to TR60 of 30 mins HRT and 1m water depth at 575mAOD. Distance from Lake to CCT is 1500m. Fall on ground is constant along this 1500m.
2. Numbers and diameters for circular settlement tanks and sand filters, external and internal dimensions of CCT, theoretical and actual pipe diameters sizes will be needed to be calculated as a minimum.

Rules of thumb for design:

Surface loading settlement tanks 1m/h

HRT settlement tanks 2h

Max diameter settlement tanks 30m

Surface loading sand filters 15m/h

Sand filter depth 2m

Max diameter sand filters 3m

Static head required for sand filter operation 10m

Superficial velocity pipework 1.5m/s