Abstract: Waste water conditioning has nearly 150 years of history. During this time, a method has developed that is considered to be state of the art. While this method meets the requirements at hand, it is complicated and expensive. The novel method breaks down the rigidly entrenched method and simplifies it. In a plurality of stages, the only energy that is used is gravity, which is readily available and free of cost. Thus, an “alternative sewage treatment plant” has been developed, which has a simpler method and is less expensive in terms of investment costs and operating costs, at the same capacity, and requires only a fraction of the previous required surface area. The most important characteristic of the invention is that the novel method separates solids from waste water immediately after entering the sewage treatment plant. Mechanically purified water is much faster, easier and less expensive to purify. The paths pursued for conditioning of the sludge are also new.

Abstract: Procedure for dewatering sewage sludge comprising the steps of subjecting pumpable sludge to chemical pretreatment with addition of a flocculation agent, pre-dewatering the chemically pretreated sludge by gravity filtration and conveying the pre-dewatered sludge by gravity, dewatering the pre-dewatered sludge by pressure filtration to form a sludge cake, crumbling the sludge cake to obtain sludge cake pieces, and drying the sludge cake pieces. After the dewatering step, so hard sludge cake is formed that after crumbling the sludge cake pieces are obtained which maintain their shape in accumulated consistency. A plant for the execution of the procedure is disclosed.