THE SELECTION AND DESIGN OF ROTATING BIOLOGICAL CONTACTORS AND REED BEDS FOR SMALL SEWAGE TREATMENT PLANTS.

Author(s):  
G E FINDLAY
2013 ◽  
Vol 5 (6) ◽  
pp. 1271
Author(s):  
Daniel Ferreira de Castro Furtado ◽  
Luiz Sérgio Philippi ◽  
Carla Suntti ◽  
Ricardo Regi

Os lodos de esgotos tornaram-se uma importante questão na gestão das cidades devido ao enorme volume produzido diariamente, ao potencial de impacto ambiental e social deste produto e ao fato de seu gerenciamento e disposição serem um dos processos mais complexos em estações de tratamento de esgotos. Os objetivos deste estudo foram avaliar a eficiência de filtros plantados com macrófitas no tratamento de lodo de tanque séptico e monitorar o processo de desaguamento e mineralização do lodo acumulado no leito do filtro. O sistema foi operado semanalmente com taxa de 125 kgST/m².ano e tempo de detenção hidráulica de 6 dias. O filtro apresentou eficiências de 95, 99, 87 e 95% para os parâmetros ST, DQOt, N-NH4+ e P-PO43-, respectivamente. O lodo acumulado apresentou a maior concentração de ST (49%), 83 dias após o último ciclo de alimentação do filtro. A concentração média de ST do lodo acumulado permitiu classificá-lo como sólido duro. Palavras-chave: lodo de tanque séptico; filtros plantados com macrófitas; tratamento de lodo séptico; biossólidos. Use of Sludge Drying Reed Beds for Dewatering and Mineralization of Sludge from Septic Tank ABSTRACT The sewage sludge has become an important issue in the management of cities due to the volume produced daily, the potential environmental and social impact of this product and the fact that its management and disposition to be one of the most complex processes in sewage treatment plants. The objectives of this study were to evaluate the efficiency of sludge drying reed beds in the treatment of septic tank sludge and monitor the process of dewatering and mineralization of the residual sludge. The system was operated weekly, with rate of 125 kgST/m².year and hydraulic retention time of 6 days. The filter presented efficiencies of 95, 99, 87 and 95% for parameters TS, COD, N-NH4+ e P-PO43-, respectively. Residual sludge had the highest concentration of TS (49%), 83 days after the last cycle the filter. The average concentration of TS presented the residual sludge allowed to classify it as a solid hard. Keywords: septic tank sludge; sludge drying reed beds; treatment of septic sludge; biosolids.


1999 ◽  
Vol 40 (4-5) ◽  
pp. 383-390 ◽  
Author(s):  
P. Griffin ◽  
P. Jennings ◽  
E. Bowman

The sewage treatment facility at Himley comprises Rotating Biological Contactors (RBCs) and subsurface flow constructed reed beds in series. A recycle facility returns RBC effluent to the influent flow. Effluent total nitrogen (TN) has always been low since commissioning and the reasons were investigated. Denitrification was observed to occur in the primary settlement tank. High hydraulic loadings in the RBC biozone deteriorated BOD5 and TSS removal, but good nitrification was obtained. The relatively poor effluent from the RBC gave a carbon source allowing further denitrification through the reed beds. Ammonification caused an increase in ammoniacal nitrogen across the primary reed bed in summer. At this time strongly reducing conditions occurred within the reed beds which, in the absence of dissolved oxygen and oxidised nitrogen compounds, led to sulphate reduction and sulphide formation with odour generation. These problems were not observed at low winter temperature conditions. Effluent TN was always below 0 mg/l.


1990 ◽  
Vol 22 (3-4) ◽  
pp. 25-32 ◽  
Author(s):  
F. E. Greaves ◽  
B. Thorp ◽  
R. F. Critchley

North West Water Authority owns and operates 21 rotating biological contactors and 7 package extended aeration plants. The rotating biological contactors have performed effectively, reliably and cheaply. Site visits are required up to three times a week for simple routine maintenance, whilst desludging is required periodically, typically 3 to 9 times a year. The prefabricated extended aeration plants generally perform well but typically with more demanding operational requirements and higher capital and electricity costs than rotating biological contactors. The Authority has concluded that the rotating biological contactor is the primary option for sewage treatment for small communities.


2008 ◽  
Vol 37 (2) ◽  
Author(s):  
Maciej Walczak

Changes of microbial indices of water quality in the Vistula and Brda rivers as a result of sewage treatment plant operationThis paper reports the results of studies of microbiological changes in the water quality of the Vistula and Brda rivers after the opening of sewage treatment plants in Bydgoszcz. The study involved determining the microbiological parameters of water quality. Based on the results obtained, it was found that the quality of the water in both rivers had improved decidedly after the opening of the plants, although an increased number of individual groups of microorganisms was found at the treated sewage outlet from one of the plants.


1995 ◽  
Vol 30 (4) ◽  
pp. 565-592 ◽  
Author(s):  
A.F. Gemza

Abstract Severn Sound continues to exhibit signs of eutrophication despite initial identification of the problem in 1969 and the construction of several sewage treatment plants since then. In general, improvements in trophic state indicators have been marginal, suggesting that the sewage treatment plants have had limited success in controlling phosphorus concentrations. These discharges likely contributed to the increased total phosphorus levels and consequently the higher phytoplankton densities of the nearshore waters. Phytoplankton biovolumes were on average one order of magnitude higher than in the open waters of Lake Huron with mean summer biovolumes as high as 8.0 mm/L. Algal biovolumes were most dense in Penetang Bay, which experienced limited exchange with the main waters of the sound. No significant long-term trends were observed. Water clarity was declining significantly, however, at a rate of -0.60 to -0.78 m/year throughout the sound except in Sturgeon Bay. Total phosphorus levels were highly variable from year to year; however, concentrations from a 20-year perspective were declining in the open waters at a rate of 0.70 µg/L/year, but response was limited in nearshore areas. In Sturgeon Bay, mean annual euphotic zone total phosphorus as well as soluble reactive phosphorus levels declined by as much as 50% following the construction of a sewage treatment plant with tertiary treatment. Phytoplankton genera typical of eutrophic waters continued to dominate the algal assemblage but members indicative of mesotrophic conditions have become apparent in some areas of the sound.


1982 ◽  
Vol 14 (4-5) ◽  
pp. 143-150 ◽  
Author(s):  
F B DeWalle ◽  
D A Kalman ◽  
R Dills ◽  
D Norman ◽  
E S K Chian ◽  
...  

A total of 25 municipal sewage treatment plants were sampled, 10 of which were resampled, to determine the quantity of phenolics in the sewage, final effluent and the anaerobically digested sludge using capillary GC/MS/DS/techniques. The study noted in decreasing order of frequency in raw sewage: phenol, pentachloro-phenol, dimethyl phenol, 3-methyl, 4-chlorophenol, 2,4,6-trichloro-phenol, 2,4-dichlorophenol, 2-nitrophenol, 2-chlorophenol, 2,4-dinitro-6-methylphenol and 2,4-dinitrophenol. The maximum concentration of phenol in sewage and sludge was 2800 ppb and 4460 respectively, while similar values for pentachlorophenol were 58 and 1200 ppb. Statistically calculated concentration reductions for phenol and dimethyl phenol were generally greater than noted for tri- and pentachlorophenol. Low decreases or increases were noted for monochlorophenol and especially for dichlorophenol as a result of the chloronation of the final effluent.


1990 ◽  
Vol 22 (7-8) ◽  
pp. 113-121
Author(s):  
W. Maier

In view of the new effluent standards in West Germany, including nitrification and phosphorus elimination, many of the existing sewage treatment plants will have to be rebuilt or expanded. Another demand which will have to be dealt with in the near future is denitrification. Under consideration of the large BOD5-loads which were taken into account when designing the plants, many of them nitrify during the summer or can be easily converted to operate with nitrification. Principles for planning the upgrading of such plants have been laid down in order to achieve the required effluent concentrations. The application of these principles is demonstrated with examples of upgraded plants.


1991 ◽  
Vol 24 (7) ◽  
pp. 133-148 ◽  
Author(s):  
A. Peter ◽  
F. Sarfert

In investigations concerning sludge bulking in Berlin enhanced biological phosphorus removal was first observed unexpectedly. Because since 1986 an officially preset limit of 2 mg TP/l must be kept in all Berlin wastewater discharges it was decided to explore the capabilities of the observed mechanism under the specific circumstances of the exciting two large treatment plants in Ruhleben (240,000 m3/d) and Marienfelde (100,000 m3/d). For this purpose some of the existing units at both plants were equipped with anaerobic zones which were generated mainly by process modifications. Additionally stage one of the Ruhleben plant was altered completely in order to investigate the combination of biological phosphorus and nitrogen removal as a special pilot study in three parallel trains. The research activities and treatment results gained in each of the two stages of the Ruhleben and in the Marienfelde plant are reported in detail. For example BOD-related phosphorus removal rates were obtained ranging from 2.3-4.5 mg TP per 100 mg BOD removed. It must be stressed that all examinations were performed on full-scale conditions. At present the given limit of 2 mg TP/l in the Ruhleben plant is met without any chemical precipitation at least on average. From the beginning biological phosphorus removal will be integrated into further projected extensions.


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