Foaming and bulking problems in activated sludge treatment plants are associated to the presence of a variety of filamentous bacteria. However, it has been observed that M. parvicella is the most frequent filamentous microorganism causing sludge bulking and foaming, especially in treatment plants...

Sewer systems may often operate as bioreactors causing considerable wastewater quality changes and in some cases reducing the pollution load conveyed to the treatment plant. Conceptually, transformation of organic matter takes place both in the bulk water (by suspended micro-organisms) and by the...

Kinetics for the biological processes of nitrification, denitrification and carbon oxidation were studied in the aerobic and anoxic phases of a pilot scale Biological Nutrient Removal (BNR) plant treating municipal wastewater. The configuration of the treating system is based on the combination of...

The methylation of mercury has been investigated and documented mainly in sediments, fish and microorganisms, while limited number of relevant studies is available for wastewater. The procedure of mercury methylation can occur via biological pathway (by microorganisms) and via chemical or...

This paper aims at a comparative evaluation of the total cost of urban sewage processing units for several treatment systems, appropriate mainly for small capacity plants. The studied systems are: Oxidation Ditch (O.D.), Trickling Filter (T.F.), Rotating Biological Contactor (R.B.C.), Compact...

The process of nitrification in wastewater treatment is widely accepted as a two-step process. In the first step the ammonia is oxidized to nitrite, a process considered to be carried out mainly by the Nitrosomonas sp., while in the second step the Nitrobacter sp. oxidizes the nitrite to nitrate...

This paper presents a biological method for controlling odor problems caused by H2S originating from sewer networks under anaerobic conditions. The proposed method is based on the continuous addition of nitrate which oxidizes dissolved sulphide according to an autotrophic biological procedure and...

Some amounts of inert products are given into environment due to biological degradation of substrate in activated sludge system. The effluent of biological wastewater treatment consists of inert substrate in influent flow, soluble microbial products and non degradable or slowly degradable organic...

Asymmetric multilayer Al2O3 ceramic membranes with pore sizes ranging from 3 to 500 nm are synthesized in tubular form with external diameter of 14mm, internal diameter of 8mm and length of 340mm. The membrane synthesis took place on commercially available supports, with the dip-coating technique...

In this study two bench scale activated sludge systems were used, a CSTR and an SBR for the treatment of coke – oven wastewater. Both reactors were inoculated with activated sludge from a municipal wastewater treatment plant. At the first stages of operation, reactors were feed by a mixture of...

Biological treatment has been carried out in two different systems: aerated closed and threephase fluidized bed reactors for hydrocarbons removal from refinery wastewaters. For the two systems, hydrodynamic study allowed the determination of operating conditions before treatment experiments. Then...

Successful start-up of a full-scale wastewater treatment plant (WWTP) is a key issue for the succeeding operation of WWTP on the one hand and the nutritious phosphorus removal is of great concern on the other. After the construction of Mudanjiang WWTP with a flow rate of 100,000 m3 d-1 in...