Daniel Toma, Cristina-Mihaela Vîrlan and Nicolae Marcoie
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.
Costel-Cătălin Prăjanu, Daniel Toma, Cristina-Mihaela Vîrlan and Nicolae Marcoie
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.
Mihaela Avram, Mihail Luca, Nicolae Marcoie and Ştefania Chirica
Research has analyzed components of the climate and hydrological regime on the Trotuş River and its tributaries over the past 30 years. The hydrological risk was determined by natural causes, but also by anthropogenic causes. Parameters of hydroclimatic risk are represented of the torrential rainfall, flood flows, high frequency of high flows, high erosion speeds etc. The research revealed that at very low intervals (3-5 years) there were floods with very high flows. Changing the climate regime (precipitation concentration on small days) and the natural relief forms in the hydrographical basin (the Eastern Carpathian Mountains) allowed natural risk to occur in the hydrological regime of the Trotuş River. Anthropic factors, in particular, the modification of the leakage coefficient by deforestation of forests and the change of agricultural use of land with large slopes have contributed to the occurrence of anthropogenic risk in the Trotuş River basin. Corroboration of the two types of risk, natural and anthropic, has led to a hydrological disaster regime in the Trotuş River Basin.