This paper includes an analysis of the biological treatment process existing within the water supply and sewerage of Iași City. The main objective of biological treatment is the removal of solid organic substances from wastewater, the stabilization of sludge, the reduction of nutrients loads etc. The Iași City Wastewater Treatment Plant was developed in several stages since year 1968. Nowadays, the facility operates at a design flow rate of 4 m3/s during dry weather and 8 m3/s during heavy rainfalls. This study is focused on the following aspects: wastewater treatment plant’s diagram, the wastewater parameters inside the treatment plant, the biological treatment process analysis and a few conclusions.

The law on drinking water quality aims to protect human health against the effects of any type of contamination by ensuring its quality of clean and health-safe water. Many cases of illness in populations are due to the fact that in their community there is no strict regulation and control regarding the water quality at the source which supplies their water systems. Thus, special importance must be given to the drinking water supply in rural areas, considering that a large part of populated centers within this category do not benefit from centralized drinking water systems. This paper will analyze a small distribution network within a commune in Suceava County. Hydraulic and water quality analysis calculations in the distribution network were performed by means of the EPANET 2.0 software. For the water quality analysis, a surveyed factor was the variation in time of free residual chlorine concentration, this parameter being monitored along with the distribution network (corresponding both to a first order reaction in the fluid volume and at pipe wall, and to a second order reaction within the fluid volume). The hourly water consumption on a working day was considered in compliance with the Romanian standards for villages and rural areas, and the simulation was performed for a period of 72 hours.

The energy transformations involved in the operation of the pumping installations are carried out by pumping aggregates consisting of an electric motor and a pump. In order to provide a full adaptation to the users’ variable demands, variable speed motor driven pumps are used on networks (such motors being equipped with frequency converters). The paper presents a method for determining the global efficiency of a frequency converter-asynchronous motor-pump group. The method has been implemented at the Chiriţa Pumping Station, main facility within the Iasi City water supply system.

No abstract