The Experience and the Results of Operating Small Wastewater Treatment Plants

1990 ◽  
Vol 22 (3-4) ◽  
pp. 267-273
Author(s):  
Mitja Rismal

About 15 years of experience gained from operating 7 small waste water treatment plants between 150-500 p.e. and 6 plants of 2000-3000 p.e. capacity are described. All of the plants involved are low-loaded activated sludge plants with water jet aeration generated by screw or propeller pumps which both proved to be efficient in aeration while secure and simple in operation. In comparison with other types of small treatment plants in our country (rotating discs and bubble aeration activated sludge plants), they proved to be reliable and simple in operation and produce an effluent of good quality. The energy consumption and the necessary flow velocites in aeration tanks are computed and measured.

2006 ◽  
Vol 5 (2) ◽  
pp. 24 ◽  
Author(s):  
C. B. H. Mora ◽  
S. De Oliveira Jr

This work evaluates the environmental impact of Wastewater Treatment Plants (WTP) based on data generated by the exergy analysis, calculating and applying environmental impact indexes for two WTP located in the Metropolitan Area of São Paulo. The environmental impact of the waste water treatment plants was done by means of evaluating two environmental impact exergy based indexes: the environmental exergy efficiency (ηenv,exerg) and the total pollution rate (Rpol,t). The environmental exergy efficiency is defined as the ratio of the exergy of the useful effect of the WTP to the total exergy consumed by human and natural resources, including all the exergy inputs. That relation is an indication of the theoretical potential of future improvements of the process. Besides the environmental exergy efficiency, it is also used the total pollution rate, based on the definition done by Makarytchev (1997), as the ratio of the destroyed exergy associated to the process wastes to the exergy of the useful effect of the process. The analysis of the results shows that this method can be used to quantify and also optimise the environmental performance of Wastewater Treatment Plants.


2004 ◽  
Vol 50 (2) ◽  
pp. 47-53 ◽  
Author(s):  
P. Cornel ◽  
B. Weber

Irrigation periods are usually limited to vegetation periods. The quality requirements for treated wastewater for disposal and for reuse are different. The reuse of water for irrigation allows partly the reuse of the wastewater's nutrients (N and P). Outside the irrigation period the water must be treated for disposal, thus nutrient removal is often required in order to avoid detrimental effects on the receiving surface water body. Only wastewater treatment plants with different operation modes for different seasons can realise these requirements. The nitrification is the most sensitive biological process in the aerobic wastewater treatment process. At low water temperatures the nitrifying bacteria need several weeks to re-start full nitrification after periods without NH4-removal. Therefore it is necessary to develop options for waste water treatment plants which allow a fast re-start of the nitrification process. Based on theoretical considerations and computer simulations of the activated sludge treatment process, one possibility for implementing a wastewater treatment plant with different seasonal operation modes is evaluated.


1984 ◽  
Vol 16 (5-7) ◽  
pp. 587-594 ◽  
Author(s):  
A Holmberg ◽  
J Forsström

This paper studies control of activated sludge plants using recycle and wastage flow rates as control variables. The behaviour of the control algorithms was studied using simulation techniques. The results indicate that the process is not sensitive to the recycle flow rate. Wastage flow control with the objective to keep the sludge concentration constant turned out to be promising.


2017 ◽  
Vol 16 (1) ◽  
pp. 54-60 ◽  
Author(s):  
Farida Y. Achmadulina ◽  
Rustem K. Zakirov ◽  
Elena S. Balymova ◽  
Vera Denisova ◽  
Taťjána Brovdyová ◽  
...  

Abstract Activated sludge biocenoses were compared on waste-water treatment plants in the city of Kazan, Russian Federation and the city of Teplice, Czech Republic. Based on Palia-Kovnatski index, Acanthamoeba in Kazan, Epistylis in Teplice, and Acanthamoeba and Centropyxis were dominant genera in both plants. The major subdominant generas identified were Arcella, Opercularia and Aspidisca. This indicates high nitrification ability, high water purification potential and matured activated sludge. Chemical composition of the waste-water was identified as the main factor determining the sludge biocenoses diversity. Higher sludge biodiversity (Shannon, Margalef, and Sorensen indexes) was found in Kazan corresponding to more concentrated inflow water.


1994 ◽  
Vol 29 (7) ◽  
pp. 1-6 ◽  
Author(s):  
B. Sandén ◽  
C. Grunditz ◽  
Y. Hansson ◽  
G. Dalhammar

Nitrobacter and Nitrosomonas were isolated in pure cultures from two large waste water treatment plants in the Stockholm area. Using the hybridoma technique, monoclonal antibodies were produced specific for Nitrobacter and Nitrosomonas respectively. Using a competitive ELISA (enzyme linked immunosorbent assay) we can estimate cell numbers in pure cultures of the bacteria as well as in activated sludge. The antibody directed against Nitrobacter was tested with sludge from several waste water treatment plants in the Stockholm area and is able to recognise Nitrobacter, indicating a common epitope. There is a good correlation between activity measurements and cell number estimations in activated sludge indicating that we have the necessary tools to further develop a method for the quick and reliable detection and quantification of Nitrobacter and Nitrosomonas.


Author(s):  
Nancey Hafez

Enzymes are biocatalysts provided by cells and are used in most metabolic methods. Most enzymes are consisting of proteins containing tertiary amino acid which bind to co enzyme or metal ions. Enzymes are accelerating biochemical processes by some mechanisms to chemical catalysts e.g metals, metal oxides and metal ions. Enzymes can be very effective under conditions e.g (temperature, atmospheric pressure and PH). Many enzymes have hydrolyzing, oxidizing and reducing characters. Enzymatic reactions always provide less side effects reactions and fewer waste by products. That is why microbial Enzymes can give an effective and environmental safe alternatives as metabolic inorganic chemical catalysts which can be used in all over pharmaceutical industrial processes. Enzymes are used in waste water treatment. Treatment technologies depend on physico-chemical approaches in wastewater treatment plants which require skills, high operation costs (in terms of high energy and chemical demand). Wastewater treatment is operated to protect the quality of limited freshwater resources, which are most times the final discharge points of effluents, and also, to promote the reusability of expended clean water; amounts of hazardous aromatic byproducts are still generated [3, 4]. The observation shows that wastewater treatment plants, though liable to remove microcontaminants such as heavy metals, and to a far lesser extent, aromatic contaminants, were originally structured for the removal of solid wastes, ecofriendly organic matter and eutrophication stimulants from wastewater, thereby reducing eutrophicating pollution loads; the micropollutants may only be moderately affected by the chemical, physical and biological interactions within the treatment plants.


1998 ◽  
Vol 38 (8-9) ◽  
pp. 29-34 ◽  
Author(s):  
Åsa Dillner Westlund ◽  
Eva Hagland ◽  
Maria Rothman

Foaming in the digesters has been observed several times at three large waste water treatment plants in Stockholm, Sweden. The foam is caused by the filamentous organism Microthrix parvicella, a hydrophobic filament which traps the gas bubbles and creates a foam. The foam in the digesters causes economical loss and a security hazard. Different solutions to prevent problems with foaming has been tried and applied. By increasing the sludge load in the biological stage the growth of Microthrix parvicella can be reduced. Decreasing the sludge level in the digesters or installing mixers in the gas phase can prevent the foam from blocking the gas pipe. Heating (70°C, 5 min) the excess sludge has in lab scale been shown to change the foam potential of activated sludge with a high content of Microthrix parvicella and could be used as a solution to prevent foaming.


2017 ◽  
Vol 4 (5) ◽  
pp. 1189-1197 ◽  
Author(s):  
Jani Tuoriniemi ◽  
Monika D. Jürgens ◽  
Martin Hassellöv ◽  
Geert Cornelis

The quantities of engineered nanoparticles (NP) released to the environment are often influenced by their fate in waste water treatment plants (WWTP).


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