Sludge from sewage treatment, which includes human refuse and, therefore, has bacterial and viral content, is difficult to use for agricultural ends even after composting.
Recently an innovative technology has been developed in Spain, which allows the ecologically efficient conversion of this sludge and of waste water coming from sewage treatment plants, into a material that is neutral, dry and homogenous. This material, called neutral, is similar to calcium hydroxide, which is used in the cement sector; thus it can be used as a substitute for the former and also be applied to other areas, such as an additive for concrete, asphalt and ceramics.
What’s innovative about this technology is that it allows sludge to be recycled without the need for thermal energy use, additives or cogeneration. It has a global patent and is being developed by the Hera Group form Cataluña through an industrial process.
The process is based on drying the components of sludge in mixing reactors with a low proportion of lime oxide. At the same time, possible releases of ammonia and particles under a very strict limit are captured. Another advantage of the process is that it can be carried out directly in controlled garbage dumps, thereby avoiding the costs of transport and elimination.
Neutral is a product that can be easily transported in cisterns and is easily used. Among its many advantages as a substitute for calcium hydroxide in the cement industry is the reduction in fuel required and, therefore, in CO2 emissions into the atmosphere.
Ecoticias.com
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