Polishing of secondary effluent by an algal biofilm process

2002 ◽  
Vol 46 (8) ◽  
pp. 83-90 ◽  
Author(s):  
G. Schumacher ◽  
I. Sekoulov
Keyword(s):  
Carbon Dioxide ◽  
Nutrient Removal ◽  
Wastewater Treatment Plants ◽  
Low Cost ◽  
Secondary Effluent ◽  
Nitrogen And Phosphorus ◽  
Dissolved Carbon ◽  
Algal Biofilm ◽  
Faecal Bacteria ◽  
Biofilm Process

The potential in polishing secondary effluent by an algal biofilm composed of different green and bluegreen algae was investigated. During the photosynthesis process of algal biofilm oxygen was produced while dissolved carbon dioxide was consumed. This led to an increasing pH due to the change of the carbon dioxide equilibrium in water. The high pH caused precipitation of dissolved phosphates. The attached algae took up nitrogen and phosphorus during the growth of biomass. In addition to nutrient removal, an extensive removal of faecal bacteria was observed probably caused by adsorption of the algal biofilm and by photo-oxidation involving dissolved oxygen. The experimental results suggest that a low-cost, close to nature process especially for small wastewater treatment plants for nutrient removal and bacteria reduction can be developed with the aid of an algal biofilm.

Bacteria reduction and nutrient removal in small wastewater treatment plants by an algal biofilm

2003 ◽  
Vol 47 (11) ◽  
pp. 195-202 ◽  
Author(s):  
G. Schumacher ◽  
T. Blume ◽  
I. Sekoulov
Keyword(s):  
Carbon Dioxide ◽  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Wastewater Treatment Plants ◽  
Secondary Effluent ◽  
Dissolved Carbon ◽  
Attached Algae ◽  
Dissolved Carbon Dioxide ◽  
Algal Biofilm ◽  
Faecal Bacteria

Attached algae settlement is frequently observed in effluents of wastewater treatment plants at locations with sufficient sunlight. For their growth they incorporate nutrients and the surface of the algal biofilm accumulates suspended solids from the clarified wastewater. During the photosynthesis process of algal biofilms oxygen is produced while dissolved carbon dioxide is consumed. This led to an increasing pH due to the change of the carbon dioxide equilibrium in water. The high pH causes precipitation of dissolved phosphates. Furthermore an extensive removal of faecal bacteria was observed in the presence of algae, which may be caused by the activity of algae. The experimental results indicate the high potential of these attached algae for polishing secondary effluent of wastewater treatment plants. Especially for small wastewater treatment plants a post connected stage for nutrient removal and bacteria reduction can be developed with the aid of an algal biofilm.

Retrofitting conventional primary clarifiers to activated primary clarifiers to enhance nutrient removal and energy conservation in WWTPs in Beijing, China

2011 ◽  
Vol 63 (7) ◽  
pp. 1446-1452 ◽  
Author(s):  
Jia-wei Wang ◽  
Tian-zhu Zhang ◽  
Ji-ning Chen ◽  
Zhi-rong Hu
Keyword(s):  
Carbon Source ◽  
Energy Conservation ◽  
Nutrient Removal ◽  
Wastewater Treatment Plants ◽  
Test System ◽  
Biological Nutrient Removal ◽  
Aeration Tank ◽  
Secondary Effluent ◽  
Nitrogen And Phosphorus ◽  
Primary Sludge

Biological nutrient removal requires sufficient carbon source. Meanwhile, the removal of organic matter in wastewater requires energy consumption in the aeration tank. Carbon source for nutrient removal in most wastewater treatment plants with conventional primary clarifier (CPC) is generally insufficient in China. In order to increase carbon source and to save energy, a part of the CPC may be retrofitted as an activated primary clarifier (APC). In this paper, a pilot scale experiment was conducted to examine the performance of primary sludge fermentation and its effect on nitrogen and phosphorus removal. Results show that the primary sludge fermentation in APC has produced a similar VFA/TP ratio but a higher BOD5/TN ratio compared with those in the CPC effluent, and the TN concentrations in the secondary effluent are at 8.0, 10.8, and 17.4 mg/L, while TP is at 0.45, 1.10, and 2.28 mg/L when the pilot test system was fed with (1) the APC effluent, (2) 50% from the APC effluent and 50% from the CPC effluent, and (3) the CPC effluent, respectively. Results also indicate that the BOD5/TN ratio is a more sensitive factor than the VFA/TP ratio for nutrient removal and energy conservation for the APC fermentation.

Improving the effluent of small wastewater treatment plants by bacteria reduction and nutrient removal with an algal biofilm

2003 ◽  
Vol 48 (2) ◽  
pp. 373-380 ◽  
Author(s):  
G. Schumacher ◽  
I. Sekoulov
Keyword(s):  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Wastewater Treatment Plants ◽  
High Potential ◽  
High Quality ◽  
Secondary Pollution ◽  
Algal Biofilm ◽  
Biofilm Process ◽  
Suspended Algae

In wastewater ponds, bacteria numbers decrease considerably in the case of raised algae concentrations in the effluent. This shows that algae have a high potential for bacteria reduction in wastewater. Simultaneously, algae remove nutrients from the water for the formation of biomass. However, suspended algae also cause a high secondary pollution in the effluent of wastewater treatment plants. By using attached algae, as they are frequently observed as an algal biofilm in the effluent of wastewater treatment plants, the problem of separation of algae and water can be avoided. Furthermore, the algae can be removed simply from the water. In this study the possibilities for bacteria reduction and nutrient removal were examined with the aid of an algal biofilm. The results show that an algal biofilm process can be used for cases where small amounts of wastewater should be treated and a high quality of the effluent should be attained.

Optimise what you have first! Low cost upgrading of plants for improved nutrient removal

1999 ◽  
Vol 39 (6) ◽  
pp. 127-134
Author(s):  
David Solley ◽  
Keith Barr
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Wastewater Treatment Plants ◽  
Capital Expenditure ◽  
Low Cost ◽  
Nitrogen And Phosphorus ◽  
Operational Strategies ◽  
Conventional Activated Sludge

Brisbane Water has undertaken an investigation into low cost options to imprrove the removal of nitrogen and phosphorus for two of its wastewater treatment plants. Luggage Point Stage 2 (300,000 e.p.) is a conventional activated sludge plant designed for nitrification. Gibson Island (150,000 e.p.) is an extended aeration activated sludge plant designed for nitrogen removal to less than 10 mgTN/l. Extensive modelling and plant simulation were carried out to evaluate the potential of various modified operational modes before the most promising modes were trialed on the full scale plants. Operational trials are proceeding well and improved nitrogen removal to less than 3 mgTN/l for Gibson Island and to less than 10 mgTN/l for Luggage Point have been achieved. Improved phosphorus removal has also been achieved for periods at both plants (less than 4 mgTP/L for Luggage Point and less than 2.5 mgTP/l at Gibson Island). However, phosphorus removal has not been consistent and trials are ongoing to determine the sustainable level of phosphorus removal for these plants. The conclusion of the trials to date is that operational strategies can be implemented for these plants to effect the removal of substantial quantities of nitrogen and phosphorus for a minimum of capital cost. This paper presents the results of the various operational strategies that have been trialed and implemented for both plants. When considering the upgrading of a plant for improved nutrient removal, the principle of “Optimise What You Have First” can sometimes produce surprisingly high nutrient removal levels for a very modest capital expenditure.

Upgrading Wastewater Treatment Plants for Biological Nutrient Removal

1990 ◽  
Vol 22 (7-8) ◽  
pp. 53-60 ◽  
Author(s):  
B. Rabinowitz ◽  
T. D. Vassos ◽  
R. N. Dawson ◽  
W. K. Oldham
Keyword(s):  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Wastewater Treatment Plants ◽  
Design Flow ◽  
Biological Nutrient Removal ◽  
Nitrogen And Phosphorus ◽  
Conventional Activated Sludge ◽  
Recent Developments ◽  
Removal Technology ◽  
Biological Nitrogen

A brief review of recent developments in biological nitrogen and phosphorus removal technology is presented. Guidelines are outlined of how current understanding of these two removal mechanisms can be applied in the upgrading of existing wastewater treatment plants for biological nutrient removal. A case history dealing with the upgrading of the conventional activated sludge process located at Penticton, British Columbia, to a biological nutrient removal facility with a design flow of 18,200 m3/day (4.0 IMGD) is presented as a design example. Process components requiring major modification were the headworks, bioreactors and sludge handling facilities.

Influence of Hydraulic Loading Rate on Horizontal Zeolite Wetland Effluent Quality

2012 ◽  
Vol 573-574 ◽  
pp. 659-662
Author(s):  
Hao Wang
Keyword(s):  
Wastewater Treatment ◽  
Loading Rate ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Secondary Effluent ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Hydraulic Loading Rate ◽  
Effluent Quality ◽  
Hydraulic Loading

In Tangshan area, the secondary effluent of wastewater treatment plants was used for this study. Horizontal zeolite wetland was carried out treating it. Hydraulic loading rate was the parameters for analyzing the nitrogen and phosphorus removal efficiency of pollutants from the secondary effluent of wastewater treatment plant. Zeolite constructed wetlands showed different behaviors for nitrogen and phosphorus removals.Under the optimum hydraulic loading rate, the primary pollutions were removed to a large extent.

Innovative low cost procedure for nutrient removal as an integrated element of a decentralised water management concept for rural areas

2001 ◽  
Vol 44 (1) ◽  
pp. 105-112 ◽  
Author(s):  
M. Burde ◽  
F. Rolf ◽  
F. Grabowski
Keyword(s):  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Rural Areas ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Low Cost ◽  
Fixed Bed ◽  
Extreme Rainfall ◽  
Fixed Bed Reactor ◽  
Soil Zone

The absence of large rivers with rather high niveau of self purifying effect in parts of east Germany leads to a discharging of the effluent of wastewater treatment plants into the groundwater in many cases. One useful consequence is the idea of realisation of decentralised measures and concepts in urban water resources management concerning municipal wastewater as well as rainfall, precipitation. At the same time, only the upper soil zone - a few decimetres - is water - saturated and thus discharge effective, even when extreme rainfall takes place. Underneath, however, there generally exists an unsaturated soil zone, which is up to now a rather unexplored retardation element of the hydrologic- and substrate-cycle. Nutrient removal in small wastewater treatment plants that are emptying into ground waters is often beneficial. The presented studies optimised an inexpensive method of subsequent enhanced wastewater treatment. The developed reactor is similar to a concentrated subsoil passage. The fixed bed reactor is divided in two sections to achieve aerobic and anoxic conditions for nitrification/denitrification processes. To enhance phosphorus removal, ferrous particles are put into the aerobic zone. Two series of column tests were carried out and a technical pilot plant was built to verify the efficiency of the process. The results show that this method can be implemented successfully.

Biological nutrient removal model No.1 (BNRM1)

2004 ◽  
Vol 50 (6) ◽  
pp. 69-70 ◽  
Author(s):  
A. Seco ◽  
J. Ribes ◽  
J. Serralta ◽  
J. Ferrer
Keyword(s):  
Nutrient Removal ◽  
Volatile Fatty Acids ◽  
Wastewater Treatment Plants ◽  
Biological Nutrient Removal ◽  
Model Parameters ◽  
Nitrogen And Phosphorus ◽  
Hindered Settling ◽  
Whole Plant ◽  
Bacterial Groups ◽  
Removal Model

This paper presents the results of the work carried out by the CALAGUA Group on Mathematical Modelling of Biological Treatment Processes: the Biological Nutrient Removal Model No.1. This model is based on a new concept for dynamic simulation of wastewater treatment plants: a unique model can be used to design, simulate and optimize the whole plant, as it includes most of the biological and physico-chemical processes taking place in all treatment operations. The physical processes included are: settling and clarification processes (flocculated settling, hindered settling and thickening), volatile fatty acids elutriation and gasÐliquid transfer. The chemical interactions included comprise acidÐbase processes, where equilibrium conditions are assumed. The biological processes included are: organic matter, nitrogen and phosphorus removal; acidogenesis, acetogenesis and methanogenesis. Environmental conditions in each operation unit (aerobic, anoxic or anaerobic) will determine which bacterial groups can grow. Thus, only the model parameters related to bacterial groups able to grow in any of the operation units of a specific WWTP will require calibration. One of the most important advantages of this model is that no additional analysis with respect to ASM2d is required for wastewater characterization. Some applications of this model have also been briefly explained in this paper.

scholarly journals Benchmarking biological nutrient removal in wastewater treatment plants: influence of mathematical model assumptions

2012 ◽  
Vol 65 (8) ◽  
pp. 1496-1505 ◽  
Author(s):  
Xavier Flores-Alsina ◽  
Krist V. Gernaey ◽  
Ulf Jeppsson
Keyword(s):  
Wastewater Treatment ◽  
Electron Acceptor ◽  
Nutrient Removal ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Critical Discussion ◽  
Decay Rates ◽  
Biological Nutrient Removal ◽  
Nitrogen And Phosphorus ◽  
Reference Case

This paper examines the effect of different model assumptions when describing biological nutrient removal (BNR) by the activated sludge models (ASM) 1, 2d & 3. The performance of a nitrogen removal (WWTP1) and a combined nitrogen and phosphorus removal (WWTP2) benchmark wastewater treatment plant was compared for a series of model assumptions. Three different model approaches describing BNR are considered. In the reference case, the original model implementations are used to simulate WWTP1 (ASM1 & 3) and WWTP2 (ASM2d). The second set of models includes a reactive settler, which extends the description of the non-reactive TSS sedimentation and transport in the reference case with the full set of ASM processes. Finally, the third set of models is based on including electron acceptor dependency of biomass decay rates for ASM1 (WWTP1) and ASM2d (WWTP2). The results show that incorporation of a reactive settler: (1) increases the hydrolysis of particulates; (2) increases the overall plant's denitrification efficiency by reducing the SNOx concentration at the bottom of the clarifier; (3) increases the oxidation of COD compounds; (4) increases XOHO and XANO decay; and, finally, (5) increases the growth of XPAO and formation of XPHA,Stor for ASM2d, which has a major impact on the whole P removal system. Introduction of electron acceptor dependent decay leads to a substantial increase of the concentration of XANO, XOHO and XPAO in the bottom of the clarifier. The paper ends with a critical discussion of the influence of the different model assumptions, and emphasizes the need for a model user to understand the significant differences in simulation results that are obtained when applying different combinations of ‘standard’ models.

scholarly journals Production of Methane From Microalgae Biofilms Growing in Wastewater Treatment Plants in the Canary Islands

2017 ◽  
pp. 904-917
Author(s):  
Giovana O. Fistarol ◽  
Mario Rosato ◽  
Nerieida M. R. Rodríguez ◽  
Mauela A. Bastidas ◽  
Paulo Sérgio Salomon ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Canary Islands ◽  
Nutrient Removal ◽  
Biomass Yield ◽  
Wastewater Treatment Plants ◽  
Low Cost ◽  
Treatment Plant ◽  
Methanogenic Bacteria ◽  
Biofuel Production ◽  
Gran Canaria

Two recurrent topics among the scientific community are the use of microalgae in wastewater treatment plants as a biological agent for nutrient removal, and, more recently, the use of microalgae for biofuel production. In this study we have analysed the possibility of coupling these two processes, using microalgae that naturally form biofilms on wastewater treatment tanks to produce methane. The proposal is to develop a low cost, environmental friendly methodology, with the economical and environmental advantages of enhancing the removal of nutrients from wastewater, and producing sustainable biofuel. A methane assay using microalgae biofilms from the primary and secondary treatment tanks from a wastewater treatment plant (WWTP) on the Canary Islands (EDAR-del Sureste, Gran Canaria, Spain) showed that, when this substrate is added to a suitable methanogenic bacteria, in this case marine sludge from a fish farm, it gives a methane yield of 0.104 Nm3 kg-1 VS. We also checked the in situ biomass yield of the biofilm (3.16 g AFDW m-2 d-1 and 7.71 g AFDW m-2 d-1, for the primary tank and secondary tank respectively), and the growth of this biofilms in photobioreactors (PBR). When grown in PBR, the algae composition of biofilm from the primary tank becomes dominate by a unicellular chlorophyta and produces 0.24 kg AFDW m- 3 d-1 of biomass; while biofilm from the secondary tank becomes dominated by the filamentous chlorophyta Stigeoclonium, and has a biomass yield of 0.48 kg AFDW m-3 d-1. The biofilms growing the WWTP of the EDAR del Sureste, in Gran Canaria, are a free naturally available source of biomass, and we have shown in this study that this biofilm, besides being used as a natural agent for nutrient removal in a WWTP, it has also the potentialof being used as a low cost, green source of biomass for methane production.

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