TENZA offers comprehensive solutions for waste water and sludge treatment and removal for sewage treatment plants focusing on sludge sanitation by employing the pasteurization method with subsequent waste heat utilization as required by Regulation of the Ministry of the Environment No. 382 to implement Act No. 185/2001 Coll. and Directive 86/278/EC. Sanitised sludge can be reused as farm fertilizer, for composting or possibly land reclamation. Thanks to its favourable pH and higher nitrogen content in comparison with liming, the application of sludge treated in the above manner is much wider. The heat necessary for pasteurization is mostly recovered and used for heating septic tanks and pre-heating raw sludge.
The pasteurization line consists of a pasteurization apparatus, a sludge accumulation chamber, pumps, pipe connections and armatures. The heat sources are represented by hot water boilers with minimum water temperature 90 °C. The pasteurization apparatus is a device intended for sludge processing. Sludge is heated up to 70 °C and this temperature is kept for a defined period of time to kill germs (enterococcus, thermo-resistant bacteria and salmonella). The homogenizing mixing process provides intensive heat transfer and prevents blockage. The steps following pasteurization are heat recuperation and treated sludge draining.
Pasteurization can be performed also after aerobic stabilization of sludge to guarantee safe sanitization and better drainability of treated sludge.
Pasteurization of aerobic stabilized sludge makes it possible to achieve better drainability and therefore reduce sludge disposal costs.
Sludge pasteurization can be performed after anaerobic stabilization (post-pasteurization) or before anaerobic stabilization (pre-pasteurization). The latter results in improved hygienic conditions of further sludge processing as well as increased production of biogas and deeper sludge stabilization during aerobic processing due to partial thermal decomposition or thermolysis.
Energy audits of sewage treatment plants
TENZA performs energy audits of sewage treatment plants in accordance with Act No. 406/2000 Coll. of 25 October 2000. Such an audit may give recommendations for possible use of biogas produced by anaerobic stabilization of sludge to generate electricity in a combined heat and power unit (green electricity). The aim of measures based on conclusions of energy audits is to save energy and minimize operating costs.