INNOVATIVE SMALL BIOPOWER SYSTEMS SOLVING WWT PLANTS SLUDGE DISPOSAL PROBLEMS.

摘要

Water supply, use and waste water treatment are strongly linked to the economic and social development of Countries and an indicative index of the development state of each Country is the percentage of the population connected to public water supply or to urban waste water collection and treatment. To avoid serious environmental problems, it is strongly desirable that the developing Countries will increase in a short period their percentages to reach the same levels of the developed ones. Collecting and treating bigger and bigger quantities of waste water has also some drawbacks; and one of the main open item is that Waste Water Treatment (WWT) plants generate big amounts of sludges which are sent to disposal with increasing difficulty and costs due to new restrictive disposal regulations. Disposal alternatives are: spreading in agricultural land; composting; landfilling and incineration. Many of these possible alternatives are becoming very difficult to pursue or are already completely forbidden in many areas and this situation generate higher disposal costs for plant Operators often reverse charged on water bills. In this framework WWT plants Operators are forced to find possible alternatives to traditional disposal more cost effective since further increases in their customers bills could not be accepted by the local communities. A viable solution to this problems is to realize small scale power systems able to convert locally WWT plants sludges. These power systems are based on a innovative pyrolytic reactor allowing the creation of a complete small power plant able to handle the WWT end-line sludges. The proposed solution includes a sludge storage system, a low-temperature dryer, a power generation section and a "zero emission" gases and odour system and is designed to be an end-line section completely autonomous without any need of integration and interference with the existing WWT process and able to convert a problem into a benefit. The European dimension of the disposal problem will be outlined and the design details of an on-going project in Italy will be analyzed giving the current state of the art of the technologies used, of the solved and open items and on the economic aspects connected to the project.