Thursday, November 30, 2006

Waste Water Treatment

A standard wastewater treatment train would typically consist of a primary clarifier system to remove solid and floating materials, a secondary treatment system consisting of an aeration basin followed by flocculation and sedimentation or an activated sludge system and secondary clarifiers, a tertiary biological nitrogen removal system, and a final tertiary disinfections unit.

The aeration basin/activated sludge system removes organic material by growing bacteria. The secondary clarifier removes the activated sludge from the water. The tertiary system is becoming more prevalent to remove nitrogen and phosphorus and do final disinfections of the water prior to its discharge to a surface water stream or ocean outfall. Before reentering into a body of water, the wastewater gets treated under a multi-stage process then only the water gets renovated and it is used for application

Anaerobic processes are widely applied in the treatment of industrial wastewaters and biological sludge. Some wastewater may be highly treated and reused as reclaimed water. For some wastewaters ecological approaches using reed bed systems such as constructed wetlands may be appropriate. Modern systems include tertiary treatment by micro filtration or synthetic membranes. After membrane filtration, the treated wastewater is indistinguishable from waters of natural origin of drinking quality.

Wednesday, November 22, 2006

Pisa Tower

When I first saw it I was impressed by its inclination. Looking around I realized that I was standing at one of the most beautiful squares in the world. This square is considered to be the most ambitious monument of the Tuscan Romanesque.

If you ever happen to be close to Pisa in winter or early spring you have to visit this square, the 'Piazza dei Miracoli' as they call it here. Go there early in the morning and taste this 'Miracolo'!

It's a pity that it's not possible anymore to climb the tower. It was closed some years ago because they feared that it could collapse. I never understood why there are problems in finding a solution for stabilizing the tower. Why don't they take the tower apart and reconstruct it again, but then on a solid foundation. Maybe even reconstructing it as the architect probably intented it to be.