scholarly journals The use of pulsed flushing to improve the efficiency of polymer floating media filters

2019 ◽  
Vol 100 ◽  
pp. 00022
Author(s):  
Zhanna Govorova ◽  
Alexey Andrianov

Surface runoff from urban area is a potential source of pollution of water bodies. The composition of pollutants in surface runoff depends on various factors and seasons. The main pollutants are oil products, suspended solids, COD, chlorides and other mineral salts. Traditional wastewater treatment plants include the mechanical removal of large items, debris and leaves; sand removal; water clarification in accumulating settling tanks; chemical dosing, contact filtration and deep purification on sorption filters. Filters with inert floating polystyrene media of various types are widely used as first stage filters. The operation of industrial filters in the technological schemes of wastewater treatment strongly depends on the backwash efficiency. Floating media flushing is carried out in the direction from top to down using the water accumulated in the over-filter space. The article presents the results of the study of pulsed flushing on a model plant. Experimental study was conducted on the real wastewater treatment plant. The kinetics of suspended solids and oil products removal from filter media was studied. The operational parameters and mode of pulsed flushing were determined. The research results were used during the reconstruction of Moscow surface runoff water treatment plants.

2009 ◽  
Vol 60 (9) ◽  
pp. 2439-2445 ◽  
Author(s):  
A. Lynggaard-Jensen ◽  
P. Andreasen ◽  
F. Husum ◽  
M. Nygaard ◽  
J. Kaltoft ◽  
...  

Most wastewater treatment plants have several secondary clarifiers or even more sets of clarifiers including several secondary clarifiers, and in practice it is a well known problem that equal distribution of the load to the single clarifier (or set of clarifiers) is very difficult—not to say impossible—to obtain. If the problem is neglected, quite a big percentage of the total clarifier capacity—measured as the max. allowed hydraulic load—can be lost. Further, return sludge rates are seldom controlled by any other means than as a (typically too high) percentage of the inlet to the wastewater treatment plant—giving a varying and too low suspended solids concentration in the return sludge, which again can lead to an unnecessary use of polymer in the pre-dewatering of the surplus sludge taken from the return sludge. A control of the return sludge rate divided into two parts - control of the total return sludge flow and control of how the total flow shall be distributed between the secondary clarifiers - is able to solve the mentioned problems. Finally, as shall be demonstrated on full scale wastewater treatment plants, a considerable increase of the hydraulic capacity of the treatment plants can be obtained.


2017 ◽  
Vol 35 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Michał Marzec

AbstractThe reliability of removal of selected contaminants in three technological solutions of the household sewage treatment plants was analysed in this paper. The reliability of the sewage treatment plant with activated sludge, sprinkled biological deposit and hybrid reactor (activated sludge and immersed trickling filter) was analyzed. The analysis was performed using the Weibull method for basic indicators of impurities, BOD5, COD and total suspended solids. The technological reliability of the active sludge treatment plant was 70% for BOD5, 87% for COD and 66% for total suspended solids. In the sewage treatment plant with a biological deposit, the reliability values determined were: 30% (BOD5), 60% (COD) and 67% (total suspended solids). In a treatment plant with a hybrid reactor, 30% of the BOD5and COD limit values were exceeded, while 30% of the total suspended solids were exceeded. The reliability levels are significantly lower than the acceptable levels proposed in the literature, which means that the wastewater discharged from the analysed wastewater treatment plants often exceeds the limit values of indicators specified in currently valid in Poland Regulation of the Minister of Environment for object to 2000 population equivalent.


2001 ◽  
Vol 43 (10) ◽  
pp. 303-311 ◽  
Author(s):  
J. H. J. M. van der Graaf ◽  
J. de Koning ◽  
J. Tang

In the Netherlands almost all wastewater treatment plants have been redesigned and adapted in order to remove nitrogen, phosphorus and suspended solids to a very low level. The improved effluent quality leads to a growing interest in the reuse of effluent of the modernised wastewater treatment plants. This again results in investigations on filtration techniques as deep bed filtration and membrane filtration. At the wastewater treatment plant Ede research was done on deep bed filtration in order to develop relations between particle removal and filter performance and to explore ways of optimization. The results of the experiments are rather typical for effluent of modern Dutch wastewater treatment plants. The very low concentrations of suspended solids and precipitable substances result in poor flocculating properties. From turbidity measurements it may be concluded that the best results were obtained with a dosage of flocculant. However, the particle size measurements indicated the opposite. Suspended solids calculations, based on the particle volume distributions, showed a better removal without a dosage of flocculant. From this it is concluded that a dosage of coagulant (Fe3+ or Al3+) has an adverse effect on the removal efficiencies even at low dosages (1 mg/l).


2006 ◽  
Vol 54 (8) ◽  
pp. 101-109 ◽  
Author(s):  
G.A. Ekama ◽  
M.C. Wentzel ◽  
S.W. Sötemann

From an experimental and theoretical investigation of the continuity of influent inorganic suspended solids (ISS) along the links connecting the primary settling tank (PST), fully aerobic or N removal activated sludge (AS) and anaerobic and aerobic sludge digestion unit operations, it was found that the influent wastewater (fixed) ISS concentration is conserved through primary sludge anaerobic digestion, activated sludge and aerobic digestion unit operations. However, the measured ISS flux at different stages through a series of wastewater treatment plant (WWTP) unit operations is not equal to the influent ISS flux, because the ordinary heterotrophic organisms (OHO) biomass contributes to the ISS flux by differing amounts depending on the active fraction of the VSS solids at that stage.


2021 ◽  
Vol 264 ◽  
pp. 03013
Author(s):  
Aybek Arifjanov ◽  
Uchqun Umarov ◽  
Akmal Abdullayev

The article presents a method for calculating the parameters of treatment facilities to bring the level of precipitation and wastewater from small enterprises, shops, and services of the Republic to the level of sewage and irrigation trays. The aim is to improve the design parameters of resource-efficient wastewater treatment plants and their widespread use, increase the production capacity of local wastewater treatment plants, improve the level of wastewater treatment and prevent environmental degradation. Hydraulic calculation of the design parameters of the settling tank was carried out at the local treatment plant. The precipitator works by precipitating suspended solids and separating petroleum products from the liquid surface. At the local treatment plant, the content of petroleum products in industrial and precipitation effluents was reduced to 3 mg/l, and the number of suspended solids to 1-1.5 mg/l.


2016 ◽  
Vol 11 (2) ◽  
pp. 459-468 ◽  
Author(s):  
P. Kängsepp ◽  
J. Väänänen ◽  
K. Örning ◽  
M. Sjölin ◽  
P. Olsson ◽  
...  

Microscreening (using Discfilters) is a widely used technology for suspended solids removal in tertiary effluent streams of wastewater treatment plants. Several pilot studies have shown the feasibility of using coagulation and flocculation in combination with microscreens for advanced phosphorus removal, but the number of full-scale references is still limited. In summer 2014, the first Scandinavian full-scale Discfilter installation with 2-stage chemical pre-treatment (coagulation and flocculation) was started up at the Arvidstorp wastewater treatment plant in Trollhättan (Sweden). The results obtained during the first year of operation proved that low suspended solids and total phosphorus effluent values could be achieved (<5 and <0.2 mg/l, respectively). These results were obtained even during heavy rainfall, when biologically and primary treated water were mixed at the influent of the Discfilter installation, before the coagulation and flocculation tanks. Further analysis of the results showed that Discfilter in combination with coagulant and polymer pre-treatment is a robust and reliable technology with low energy demand (34 Wh/m3) and a high recovery (1.9 ± 0.4% of influent flow discharged as reject).


2010 ◽  
Vol 2 (5) ◽  
pp. 97-102
Author(s):  
Ala Sokolova ◽  
Mindaugas Rimeika

The paper analyzes the impact of the way of mounting a tube diffuser, the design of an aeration tank and the presence of a fixed carrier on the operational parameters of aeration systems used in small wastewater treatment plants. It was found out that the vertically mounted tube diffuser decreased standard oxygen transfer rate (SOTR) of the aeration system by approximately 20% and standard oxygen transfer efficiency (SOTE) by 25% comparing to the horizontally mounted tube diffuser. It was also defined that the design of the aeration tank might have an impact on the operation parameters of the aeration system: when the centre shell used to protect a diffuser was dismantled from a test tank, SOTR and SOTE increased by approximately 20%. It was also established that the presence of the fixed carrier in the aeration tank did not have an impact on the performance of aeration systems. Finally, research was carried out to compare the operational parameters of two diffusers of different types offered on the market and used in small wastewater treatment plants. It was found out that the performance different type diffusers might vary considerably.


2020 ◽  
Vol 82 (9) ◽  
pp. 1877-1884
Author(s):  
Güler Türkoğlu Demirkol ◽  
Gökhan Balcıoğlu ◽  
Nurtaç Öz ◽  
Moiz Elnekave ◽  
Bülent Armağan ◽  
...  

Abstract Domestic wastewaters causing pollution contain inorganic and/or organic materials. When the domestic wastewater outflows to the receiving waters, it causes physical, chemical, and biological pollution in them, and deteriorates the ecological balance of those waters. In the treatment of wastewater, various treatment methods are available depending on the pollution strength of the wastewater. Besides mechanical and biological methods, wastewater treatment with physicochemical methods is still one of the most effective and economical options. Particularly in wastewater with a high concentration of suspended solids, this method is very successful, and obtaining high suspended solids removal efficiencies is very possible. In this study, the effects of the use of coagulant and coagulant aid to be used in a treatment plant where domestic wastewater treatment is carried out are determined to increase the treatment efficiency of a biological treatment that comes later in the stages of the treatment. The effluent of the pre-settling tank may contain a lot of suspended solids. This presence of excess suspended solids decreases the efficiency at other levels of treatment and causes energy loss. In the experiments, the standard jar and inhibition tests are done as a method. As a result of the conducted studies, it is determined that the FeCl3, Synthetic coagulant LP 526, FeClSO4, and the combination of anionic polyelectrolyte yield the best results in the removal of the parameters of chemical oxygen demand (COD), total suspended solids (TSS), and volatile suspended solids (VSS). While FeCl3, APE 65, APE 85, Synthetic coagulant LP 526, and FeClSO4 did not show any inhibition effect in the sludge, APE 67, CPE 84, and (Al2(SO4)3 are found to cause inhibition in the sludge.


Author(s):  
Li He ◽  
Tao Tan ◽  
Zhixi Gao ◽  
Leilei Fan

Previous studies on the water quality of surface runoff often focused on the chemical oxygen demand (COD), nitrogen, phosphorus, and total suspended solid (TSS), but little is known in terms of the inorganic suspended solids (ISS). This research investigated the effects of ISS carried by surface runoff on the treatment efficiency of the pretreatment facilities and the ratio of mixed liquor volatile suspended solid to mixed liquor suspended solid (MLVSS/MLSS) of the activated sludge in a wastewater treatment plant (WWTP) with the anaerobic-anoxic-oxic (AAO) process in Chongqing city, China. The results showed that the surface runoff had a long-lasting impact on the grit removal capacity of the grit chamber, affecting the normal operation after the rainfall. In contrast, the primary sedimentation tank showed strong impact resistance with higher removal rates of COD, TSS, and ISS. Nonetheless, the primary settling tank aggravates the removal of organic carbon in sewage during rainfall, having a negative impact on subsequent biological treatment. The ISS in the surface runoff could increase the sludge concentration and decrease the MLVSS/MLSS ratio. After repeated surface runoff impact, the MLVSS/MLSS ratio in the activated sludge would drop below even 0.3, interrupting the normal operation of WWTP.


1987 ◽  
Vol 19 (3-4) ◽  
pp. 669-680 ◽  
Author(s):  
Gordon W. Speirs ◽  
Robert D. Hill

As part of a full-scale project to demonstrate the advantages of using automated process control in wastewater treatment plants, on-line sensors used in various control loops were calibrated and/or verified during control system commissioning and startup. The on-line measurements included liquid flow rates, air flow rates, suspended solids concentrations, and dissolved oxygen concentrations. The methods used to confirm instrument performance are presented along with results that show that several instruments were found to operate outside the manufacturers' written specifications. In addition, on-line methods which can help determine when recalibrations are required, and thereby help to reduce maintenance costs and ensure reliability, are also presented.


Sign in / Sign up

Export Citation Format

Share Document