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World energy systems development is based on the use of renewable sources, their valorisation benefits of technical and economical stimulating actions. The main disadvantage is related to the low efficiency caused by low energy density and high value investments. The cost of renewable energy is higher than energy coming from conventional sources. Reducing the costs of producing unconventional energy can be achieved by integrating economic and social activities into the system, providing futher benefits. From the potential point of view, it is estimated that biomass occupies the first place in a ranking of unconventional energies. Biomass boosted by anaerobic fermentation with biogas production and cogeneration can provide "peak" energy production and can balance energy systems. Waste utilized by these processes involves reducing environmental impacts by diminushing managed volumes and efficient control. In the present paper are characterized by calculations aspects of the exploitation and elements regarding the optimization of some high-capacity fermenters of a wastewater treatment system.

Waste water treatment plants are complex systems consisting of construction, hydro-mechanical, electrical, monitoring and automation equipment. Monitoring activities emphasize that the processes are dynamic; wastewater quality at the entering point of treatment plant varies in a wide range. Treatment technologies adopted must reduce major pollutants; that involves nitrification-denitrification processes and biological and chemical reduction of phosphorus through mechanical-chemical-biological treatment pathways. Increasing the activated sludge concentration in a wastewater treatment plant is an effective method by altering the process dynamics and by reducing the produced sludge volume. There are proposed and discussed in terms of technical and cost efficiency different technological wastewater treatment schemes. In Romania, wastewater treatment plants and sewage systems operating involve processes based on the new systems overrated, there is mandatory to diminish quantities in water supply systems and to exclude improperly working of wastewater pre-treatment stations. Those operations impose technological measures ensuring efficient functioning regardless the service conditions.

In the context of execution of construction works close to an academic building, it was measured the sound level on construction site, near its enclosure, outside and inside the building, in different situations and equipment operation. The recorded values are compared to the values stipulated by legislation concerning the noise and conclusions are drawn regarding the regime of teaching activities during the execution period. © 2014 The Authors. Published by Elsevier Ltd. Selection and peer-review under responsibility of DAAAM International Vienna.

Pumps being components of wastewater treatment systems, water supply systems and irrigation systems are exploited under a wide range of operating parameters. User requirements make these equipments to work with functioning parameters close to the limit values recommended by the manufacturers, on low energy efficiency regime. In this manner vibrations occur during operation, which could be under specific rotation, different pump characteristics, dynamic or static load. The present paper would like to emphasize by measurements the vibrations arising from pumps operated at low speeds, to establish dependency relations. Diagnosis of the phenomena is mandatory because it generates malfunction, damage and even pump or system failure. Results obtained and their interpretation are the scientific base for improvement method technical recommendations, for process automation and service programs creation in order to ensure reliable operation and to help repair cost decreasing.