Distribution of heterotrophic and autotrophic organisms in a biological aerated filter

2008 ◽  
Vol 3 (3) ◽  
Author(s):  
O. González-Barceló ◽  
S. González-Martínez
Keyword(s):  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Low Cost ◽  
Ammonia Nitrogen ◽  
Organic Load ◽  
Homogeneous Distribution ◽  
Municipal Wastewater Treatment ◽  
Filter Media ◽  
Aerated Filter ◽  
Secondary Settling

Biological aerated filtration is a viable option for small municipal wastewater treatment plants. A low cost filter media was obtained by triturating volcanic rock. An apparent porosity of 46 % and a specific surface area of 395 m2/m3·d were obtained once the filter was packed by using a grain size of 8.2 mm. The performance of the system, operated as a biological filter, was evaluated under an average organic load of 2.6±0.4 kgCODT/m3·d (6.7±1.1 gCODT/m2·d) without primary and secondary settling. The average CODT decreased from 220 mg/l in the influent to 88 mg/l in the effluent and the CODD was decreased from 148 mg/l in the influent to 50 mg/l in the effluent. The filter media, in combination with the biofilm, allowed a 75 % TSS removal. The ammonia nitrogen decreased from 51 mg/l in the influent to 33 mg/l in the effluent. The maximum flux coefficients of 9.3gCODdissolved/m2·d and 2.9gNH4-N/m2·d at the biofilm surface were used to simulate, with the Michaelis-Menten model, the profiles of dissolved COD, ammonium and nitrates through the aerated filter. It was possible to conclude that the backwashing procedure removed the excess biomass and was responsible for a homogeneous distribution of heterotrophic and autotrophic microorganisms along the filter depth.

Upgrading of Small Municipal Wastewater Treatment Plants with Heavy Dairy Loading by Introduction of Aerated Submerged Biological Filters

1990 ◽  
Vol 22 (7-8) ◽  
pp. 191-198 ◽  
Author(s):  
Hallvard Ødegaard ◽  
Bjørn Rusten
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Combined Treatment ◽  
Organic Load ◽  
Municipal Wastewater Treatment ◽  
Biological Filter ◽  
Municipal Wastewater Treatment Plants ◽  
Insufficient Knowledge ◽  
Biological Filters

Most of the dairies in Norway discharge their wastewater to the municipal sewers. Insufficient knowledge about the organic load coming from the dairies, has resulted in inadequate design and organic overloading in the municipal wastewater treatment plants of this category. Several of the plants that originally based their biological process upon RBC as the bioprocess, have experienced mechanical breakdown of the RBC system. The submerged biological filter (SABF) has been introduced as an alternative biofilm method that may be used when broken down RBC-plants (or activated sludge plants) are to be upgraded. The paper describes results from pilot-plant experiments on dairy waste when the SABF is used for pretreatment, as well as results from plants in practice where the SABF is used for combined treatment of the dairy and municipal wastewater. It is shown how pretreatment in a balancing tank may be established, and results from the use of an alternative floating biofilm media are given.

scholarly journals Effect of sewage sampling frequency on determination of design parameters for municipal wastewater treatment plants

2020 ◽  
Author(s):  
T. Gehring ◽  
E. Deineko ◽  
I. Hobus ◽  
G. Kolisch ◽  
M. Lübken ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Sampling Frequency ◽  
Organic Load ◽  
Design Parameters ◽  
Data Sets ◽  
Municipal Wastewater Treatment

Abstract The uncertainty associated with the determination of load parameters, which is a key step in the design of wastewater treatment plants (WWTPs), was investigated on basis on data sets from 58 WWTPs. A further analysed aspect was the organic load variations associated with variable sewage temperatures. Data from 26 WWTPs with a high inflow sampling frequency was used to simulate scenarios to investigate the effect of lower sampling frequencies through a Monte Carlo approach. The calculation of 85-percentile values for chemical oxygen demand (COD) loadings based on only 26 samples per year is associated with a variability of up to ±18%. Approximately 90 samples per year will be necessary to reduce this uncertainty for estimation of COD loadings below 10%. Hence, a low sampling frequency can potentially lead to under- or overestimation of design parameters. Through an analogous approach, it was possible to identify uncertainties of ±11% in COD loading when weekly average data was used with 4 samples per week. Finally, a tendency of lower COD input loads with increasing temperatures was identified, with a reduction of about 1% of the average loading per degree Celsius.

Multi-stage constructed wetland systems for municipal wastewater treatment

2013 ◽  
Vol 67 (7) ◽  
pp. 1590-1598 ◽  
Author(s):  
F. Masi ◽  
S. Caffaz ◽  
A. Ghrabi
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Average Concentration ◽  
Organic Load ◽  
Municipal Wastewater Treatment ◽  
Multi Stage ◽  
Disinfection Process ◽  
Municipal Wastewater Treatment Plants

In the present paper the detailed design and performances of two municipal wastewater treatment plants, a four-stage constructed wetlands (CW) system located in the city of Dicomano (about 3,500 inhabitants) in Italy, and a three-stage CW system for the village of Chorfech (about 500 inhabitants) in Tunisia, are presented. The obtained results demonstrate that multi-stage CWs provide an excellent secondary treatment for wastewaters with variable operative conditions, reaching also an appropriate effluent quality for reuse. Dicomano CWs have shown good performances, on average 86% of removal for the Organic Load, 60% for Total Nitrogen (TN), 43% for Total Phosphorus (TP), 89% for Total Suspended Solids (TSS) and 76% for Ammonium (NH4+). Even the disinfection process has performed in a very satisfactory way, reaching up to 4–5 logs of reduction of the inlet pathogens concentration, with an Escherichia coli average concentration in the outlet often below 200 UFC/100 mL. The mean overall removal rates of the Chorfech CWs during the monitored period have been, respectively, equal to 97% for TSS and Biochemical Oxygen Demand (BOD5), 95% for Chemical Oxygen Demand (COD), 71% for TN and 82% for TP. The observed removal of E. coli by the CW system was in this case 2.5 log units.

Characterization and application of surface-molecular-imprinted-polymer modified TiO2 nanotubes for removal of perfluorinated chemicals

2016 ◽  
Vol 74 (6) ◽  
pp. 1417-1425 ◽  
Author(s):  
Lei Hu ◽  
Yi Li ◽  
Wenlong Zhang
Keyword(s):  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Low Cost ◽  
Average Diameter ◽  
Municipal Wastewater Treatment ◽  
Wastewater Reclamation ◽  
Adsorption Selectivity ◽  
Secondary Effluents ◽  
Perfluorinated Chemicals ◽  
Tio2 Nts

The removal of perfluorinated chemicals (PFCs) during wastewater reclamation is a great concern. However, the existing advanced treatment processes are inefficient for the removal of PFCs from secondary effluents of municipal wastewater treatment plants (WWTPs) because other coexistent pollutants with less environmental significance are removed simultaneously. Therefore, research on high-selectivity, low-cost removal methods is needed. The S-MIP-TiO2 nanotube (NT) photocatalysts were fabricated, characterized and tested for removal of PFCs from wastewater for the first time. Scanning electron microscopy and Fourier transform infrared spectroscopy show that the TiO2 NTs (average diameter 60 nm) were successfully imprinted with functional groups (i.e. carboxyl). The adsorption selectivity and photocatalytic activity of the S-MIP-TiO2 NTs over perfluorooctanoic acid (PFOA) were improved compared with neat TiO2 NTs and interestingly, were higher at low PFOA concentrations (10 to 100 ng/L, as normal PFC concentrations in secondary effluents) than at high concentrations (10 to 1,000 mg/L). With S-MIP-TiO2 NTs used as photocatalysts, some representative PFCs were selectively and rapidly removed from secondary effluents of a municipal WWTP. S-MIP-TiO2 NTs exhibited excellent regeneration performance. Thus, photocatalytic treatment using is promising for effective removal of PFCs from secondary effluents of municipal WWTPs.

scholarly journals Šedá vodní stopa jako ukazatel udržitelného vypouštění odpadních vod – případová studie Povodí Ohře

Entecho ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 12-18 ◽  
Author(s):  
Libor Ansorge ◽  
Lada Stejskalová ◽  
Jiří Dlabal ◽  
Jiří Kučera
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Sustainability Assessment ◽  
Water Footprint ◽  
Wastewater Treatment Plants ◽  
Ammonia Nitrogen ◽  
Municipal Wastewater Treatment ◽  
Grey Water ◽  
Municipal Wastewater Treatment Plants ◽  
Assimilation Capacity

Cíle udržitelného rozvoje OSN požadují mimo jiné i zlepšit kvalitu vody snížením jejího znečišťování, zamezením vyhazování odpadů do vody a minimalizací vypouštění nebezpečných chemických látek do vody. Jedním z nástrojů, který lze využít pro posouzení udržitelnosti vypouštění znečištění do vod je vodní stopa. V článku je popsána analýza šedé vodní stopy velkých komunálních čistíren v povodí Ohře. Pro analýzu byly vybrány komunální čistírny odpadních vod uvedené státním podnikem Povodí Ohře ve zprávách vodohospodářské bilance. Byla stanovena asimilační kapacita toku pro jednotlivé znečišťující látky hlášené provozovateli čistíren odpadních vod pro účely vodohospodářské bilance, spočtena šedá vodní stopa látek vstupujících na čistírnu odpadních vod (produkované znečištění) a vypouštěných do recipientů v odpadní vodě. Posouzení udržitelnosti bylo provedeno k dlouhodobému průměrnému průtoku recipientem. Analýza ukázala, že asimilační kapacita vodních toků je nejvíce vytěžována vypouštěním celkového fosforu a amoniakálního dusíku. Zároveň z analýzy vyplynulo, že čistírny odpadních vod, až na výjimky, čistí vodu dostatečně a asimilační kapacita vodního toku nebývá vyčerpána. ----------- The Sustainable Development Goals (SDGs), adopted by all United Nations Member States in 2015, call, among others, for the improvement of water quality by reducing water pollution, avoiding waste disposal in water and minimizing hazardous chemicals discharge into water. One of the tools that can be used for the sustainability assessment of pollution discharge into water is the water footprint. The paper calculates the grey water footprint of large municipal wastewater treatment plants in the Ohře River basin, located in the Czech Republic. Municipal wastewater treatment plants listed by the state-owned enterprise Povodí Ohře in Water Balance Management reports were selected for the analysis. The receiving body assimilation capacity for individual pollutants was determined and the grey water footprint at the inlet and outlet of the WWTP was calculated. Subsequently, the sustainability assessment of the WWTP discharges were carried out and related to the long-term average flow rates in the receiving water body. The analyses showed that the assimilation capacity of the watercourse is mostly utilized by the discharge of total phosphorus and ammonia nitrogen. The analysis also showed that (with some exceptions) the wastewater treatment plants treat water sufficiently and the assimilation capacity of the watercourse is not exhausted.

scholarly journals Intensification of activated sludge sedimentation processes by means of vacuuming

Vestnik MGSU ◽  
2021 ◽  
pp. 370-380
Author(s):  
Artem A. Kulakov ◽  
Alina F. Filatova
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Settling Tank ◽  
Municipal Wastewater Treatment ◽  
Treated Water ◽  
Mixed Liquor ◽  
Municipal Wastewater Treatment Plants ◽  
Secondary Settling

Introduction. The mixed liquor of nitrogen removal wastewater treatment plants is characterized by a high concentration of nitrates and dissolved oxygen at the inlet to the secondary settling tank. In the sludge layer of secondary sedimentation tanks, conditions of decreased oxygen content and uncontrolled denitrification processes take place. This leads to the floating up and removal of sludge with the effluent and secondary pollution of treated water. The purpose of this article is to study the parameters of activated sludge sedimentation in municipal wastewater treatment plants and their intensification by means of vacuuming. Materials and methods. The studies were carried out under laboratory conditions. Activated sludge vacuuming and sedimentation processes were simulated. Diagrams of the “sludge-water” phase reduction (Kinsh curves) were drawn. Mathematical and graphic processing of the results was carried out. Results. Biological treatment of municipal wastewater (aerotank — secondary settling tank) and methods of its intensification by influencing the activated sludge were considered in this article. Trends of activated sludge (at different concentrations of mixed liquor suspended solids) sedimentation were experimentally obtained for municipal wastewater treatment plants. The process of sludge vacuuming was researched, the process efficiency was determined as a function of the treatment time. Conclusions. Vacuuming allows removing gases from the fluid, which accelerates the process of sludge separation from the treated water and prevents it from floating to the surface. The treated sample is characterized by better sedimentation characteristics, density, coarseness and integrity of flakes. The optimal duration of mixed liquor vacuuming before sedimentation is 0.5 minutes; this accelerates the processes of subsequent sedimentation and reduces the removal of sludge with treated water. The results of laboratory tests can be applied to the design of the mixed liquor vacuuming unit before the secondary sedimentation tanks and its sludge separation.

Performance of a subsurface constructed wetland in Iran

1998 ◽  
Vol 38 (1) ◽  
pp. 345-350 ◽  
Author(s):  
A. Badkoubi ◽  
H. Ganjidoust ◽  
A. Ghaderi ◽  
A. Rajabi
Keyword(s):  
Constructed Wetland ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Low Cost ◽  
Pilot Scale ◽  
Municipal Wastewater Treatment ◽  
Natural Systems ◽  
Acceptable Quality ◽  
The Government ◽  
Municipal Wastewater Treatment Plants

The high capital, operational and maintenance costs of municipal wastewater treatment plants in Iran are a concern for the government. Wastewater treatments in natural systems have shown suitable methods for their low cost. The performance of a pilot-scale subsurface constructed wetland with Phragmites australis to treat municipal wastewater has been investigated. The purpose of this study was to determine the surface area requirement per person in an arid region to achieve an acceptable quality in terms of discharge standards. Experiments were carried out in two cells (15 × 10 mxm) with media size ranging from 4-8 mm. One cell was used as blank (unplanted) and the other one was planted. Different hydraulic loading rates ranging from 5 to 20 L/min were used. Minimum land requirement was determined to be 1-2 m2/P.E. to reduce COD (86±4%), BOD5 (90±3%), TSS (89±4%), TN (34±6%), TP (56±5%) and fecal coliform (>99%).

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