High-Rate Retention Treatment Basins for CSO Control in Windsor, Ontario

2004 ◽  
Vol 39 (4) ◽  
pp. 449-456 ◽  
Author(s):  
Jian Guo Li ◽  
Harold Horneck ◽  
David Averill ◽  
J. Alex McCorquodale ◽  
Nihar Biswas
Keyword(s):  
Empirical Relationship ◽  
Pilot Scale ◽  
High Rate ◽  
Experimental Investigations ◽  
Combined Sewer Overflows ◽  
Column Tests ◽  
Dosage Range ◽  
Loading Rates ◽  
Combined Sewer ◽  
Removal Efficiencies

Abstract Experimental investigations were conducted to evaluate the effectiveness of a retention treatment basin (RTB) with polymer coagulation for the treatment of combined sewer overflows (CSO) at high hydraulic loading rates. The TSS removal efficiency of the pilot-scale RTB at a surface overflow rate (SOR) of 11 m/h was approximately 35% without chemical addition, and 80% with a polymer dosage range of 5 to 10 milligrams per gram of influent TSS. The results demonstrated that the use of polymer coagulation significantly improved TSS removal and allowed the SOR in the RTB to be significantly increased, resulting in smaller treatment units. An empirical relationship was established to estimate removal efficiencies as a function of overflow rate. The results also compared settling characteristics of CSO, obtained from long column tests, to removal efficiencies in the high-rate RTB.

Field facility for research and demonstration of CSO treatment technologies

1997 ◽  
Vol 36 (8-9) ◽  
pp. 391-396
Author(s):  
D. Averill ◽  
D. Mack-Mumford ◽  
J. Marsalek ◽  
R. Andoh ◽  
D. Weatherbe
Keyword(s):  
Pilot Scale ◽  
High Rate ◽  
Uv Disinfection ◽  
Combined Sewer Overflows ◽  
Combined Sewer ◽  
Treatment Technologies ◽  
Test Threshold ◽  
Vortex Separator ◽  
Solid Liquid ◽  
Solid Liquid Separation

A pilot scale study of options for the treatment combined sewer overflows is being conducted in Ontario, Canada. The objective is to achieve primary clarification equivalency in simple, high-rate satellite treatment systems. Effluent disinfection will also be required where bathing beaches are to be protected. Long column settling tests conducted with CSO suspensions indicated that approximately 40% of the suspended solids was non-settleable at the test threshold of 0.3 m/h. The use of a cationic polymer as the sole coagulant in a three metre diameter vortex separator achieved at least 50% TSS removal at surface loads up to approximately 40 m/h. The effluents from solid/liquid separation operations using the polymer coagulation strategy were more amenable to UV disinfection than those produced with metal-based coagulants. This document has been updated to include experimental results to mid-1997.

Tilapia rearing with high rate algal pond effluent: ammonia surface loading rates and stocking densities effects

2018 ◽  
Vol 78 (1) ◽  
pp. 49-56
Author(s):  
I. A. Sánchez ◽  
R. K. X. Bastos ◽  
E. A. T. Lana
Keyword(s):  
Weight Gain ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Ammonia Nitrogen ◽  
High Rate ◽  
Surface Loading ◽  
Loading Rates ◽  
Total Weight Gain ◽  
Low Weight ◽  
Total Ammonia

Abstract In two pilot-scale experiments, fingerlings and juvenile of tilapia were reared in high rate algal pond (HRAP) effluent. The combination of three different total ammonia nitrogen (TAN) surface loading rates (SLR1 = 0.6, SLR2 = 1.2; SLR3 = 2.4 kg TAN·ha−1·d−1) and two fish stocking densities (D1 = 4 and D2 = 8 fish per tank) was evaluated during two 12-week experiments. Fingerlings total weight gain varied from 4.9 to 18.9 g, with the highest value (equivalent to 0.225 g·d−1) being recorded in SLR2-D1 treatment; however, high mortality (up to 67%) was recorded, probably due to sensitivity to ammonia and wide daily temperature variations. At lower water temperatures, juvenile tilapia showed no mortality, but very low weight gain. The fish rearing tanks worked as wastewater polishing units, adding the following approximate average removal figures on top of those achieved at the HRAP: 63% of total Kjeldahl nitrogen; 54% of ammonia nitrogen; 42% of total phosphorus; 37% of chemical oxygen demand; 1.1 log units of Escherichia coli.

High-rate dissolved air flotation for water treatment

2001 ◽  
Vol 43 (8) ◽  
pp. 43-49 ◽  
Author(s):  
M. A. P. Raeli ◽  
M. Marchetto
Keyword(s):  
Reynolds Numbers ◽  
Pilot Scale ◽  
Water Velocity ◽  
High Rate ◽  
Raw Water ◽  
Parallel Plates ◽  
Dissolved Air Flotation ◽  
Removal Efficiencies ◽  
Air Flotation ◽  
Dissolved Air

This paper presents the results of an experimental investigation about the performance of a horizontal flow high-rate pilot scale Dissolved Air Flotation (HRDAF) unit containing inclined parallel plates for treating a coloured and low turbidity raw water. Experiments were performed with the DAF unit in order to verify the influence on flotation of : (i) the water velocity (Vh) between the plates, in the range 18 to 96.5 cm.min−1 with corresponding Reynolds numbers between 240 and 1060; (ii) the supplied air (S*) value ranging from 2.2 to 8.5 g of air/m3 of water ; (iii) the angle of the plates (60° or 70°). The best pilot plant operational condition was obtained applying only 4.0 g/m3 (S*) with Vh around 18 cm.min−1 for treatment of water coagulated with a Al2(SO4)3 dosage of 40 mg.l−1. In these conditions, the unit presented very good removal efficiencies of colour (90%, residual of 10 uC), turbidity (88%, residual of 0.8 NTU ) and TSS (94%, residual of 1.8 mg.l−1). Furthermore, the unit could operate at higher Vh values up to 76 cm.min−1 and still present good results. The DAF unit thus behaved as a high rate unit presenting good performance with low air requirement.

Experimental abatement data of underflow baffles for removal of floatables in the CSOs of the Greater Montréal (Canada) area

2005 ◽  
Vol 51 (2) ◽  
pp. 65-70 ◽  
Author(s):  
John F. Cigana ◽  
Martin Couture
Keyword(s):  
Pilot Scale ◽  
Horizontal Velocity ◽  
Design Criteria ◽  
Operational Cost ◽  
Flow Conditions ◽  
Combined Sewer Overflows ◽  
Follow Up Study ◽  
Combined Sewer ◽  
Rapid Flow

Underflow baffles have gained in popularity over the years as a viable mean to intercept floatables in Combined Sewer Overflows (CSOs). This choice was mainly justified by the extremely low capital cost (CAPEX) and operational cost (OPEX) of this solution, although the efficiency of underflow baffles has never been clearly proven. The only similar application to underflow baffles are scum boards in grit chambers and clarifier. However, the flow conditions at CSOs vary considerably from those in grit chambers and clarifier. For this reason, review of the behavior of floatables in a rapid flow is paramount. Only then can comprehensive design criteria for underflow baffles and overflow chambers be suggested. Pilot scale tests, performed in a 17 metres long basin at various flowrates, had already shown that a critical horizontal velocity for floatables (Vcr) may develop in the overflow chambers. In this follow up study, the fate of intercepted floatables was investigated. It appears from this latest data that permanent capture of floatables decreases rapidly with an increase in the horizontal velocity of the flow, no matter what the baffle depth. Baffle depth increases capture at lower velocities (0.17 m/s) but become irrelevant at higher velocities (0.61 m/s). This data suggests that capture efficiency of existing underflow baffles in overflow chambers can be, at best, very low whenever the horizontal velocity increases above 0.30 m/s or 1 ft/s.

Pilot-Scale Study of Satellite Treatment Options for the Control of Combined Sewer Overflows

1997 ◽  
Vol 32 (1) ◽  
pp. 169-184 ◽  
Author(s):  
J. SCHMIDT ◽  
P. SETO ◽  
D. Averill
Keyword(s):  
Treatment Options ◽  
Cost Effective ◽  
Pilot Scale ◽  
Combined Sewer Overflows ◽  
International Joint Commission ◽  
Pollution Problem ◽  
Combined Sewer ◽  
Vortex Separator ◽  
Sewer Overflows ◽  
Screen Performance

Abstract Combined sewer overflows (CSOs) have been recognized for many years as a pollution problem within the Great Lakes ecosystem. CSOs were identified as a source of contamination in 10 of the 17 Canadian “Areas of Concern” designated by the International Joint Commission, and were considered a major problem in Hamilton Harbour and the Metropolitan Toronto Waterfront. Satellite treatment systems (located upstream in the sewerage system) were identified as being significantly more cost effective than other CSO control options in a feasibility study conducted for Metropolitan Toronto. Consequently, a multi-agency initiative was established in 1993 to examine the treatment of CSOs at a pilot-scale facility in the City of Scarborough. The technologies evaluated during two experimental seasons in 1994 and 1995 included a vortex separator, a circular clarifier, a horizontal-flow plate clarifier and an inclined rotary drum screen. Performance of the technologies is being assessed against a draft policy proposed by the Ontario Ministry of Environment and Energy. Results to date have indicated that the vortex separator and the plate clarifier under “best conditions” were capable of 50% TSS removal and 30% BOD5 removal and should be capable of satisfying the policy.

scholarly journals High rate filtration for local treatment of combined sewer overflow

2019 ◽  
Vol 79 (6) ◽  
pp. 1206-1213 ◽  
Author(s):  
H. Helness ◽  
C. Sun ◽  
S. Damman ◽  
M. Ahmadi ◽  
G. Raspati ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Urban Areas ◽  
Negative Impact ◽  
Local Treatment ◽  
High Rate ◽  
Water Runoff ◽  
Combined Sewer Overflows ◽  
Sewer System ◽  
Combined Sewer ◽  
High Investment

Abstract Combined sewer overflows (CSOs) pollute receiving waters and have a negative impact on ecosystem services. In urban areas rehabilitation of the sewer system to avoid CSOs is associated with high investment costs. Furthermore, not all CSOs can be closed due to the need for hydraulic reliability of the system. Local treatment of CSO with high rate filtration offers an alternative to rehabilitation of the sewer system that is flexible with respect to design and has lower investment cost than separating sewage and storm water runoff. Results from DESSIN, a 4-year EU demonstration project, are presented. The results showed on average 50% removal of particulate matter during CSO events, with higher removal (80%) in the initial first flush period. Other constituents, for example heavy metals, were removed through their association with particles. Potential impacts on ecosystem services in the catchment and the sustainability of the solution were assessed.

Coarse media filtration - an alternative to settling in wastewater treatment

2003 ◽  
Vol 47 (12) ◽  
pp. 81-88 ◽  
Author(s):  
H. Ødegaard ◽  
Z. Liao ◽  
A.T. Hansen
Keyword(s):  
Separation Efficiency ◽  
Primary Treatment ◽  
Biofilm Reactor ◽  
High Rate ◽  
Tertiary Treatment ◽  
Loading Rates ◽  
Denitrification Reactor ◽  
Multi Media ◽  
Removal Efficiencies ◽  
Low Dosage

In this paper coarse media filtration has been analysed as an alternative to the traditional settling in primary, secondary and tertiary treatment of wastewater. Various filter media configurations were evaluated for enhanced primary filtration. It was found that a dual media configuration based on Kaldnes biofilm media (K1 and K2modified) were most suitable when taking both separation efficiency as well as filter run time into consideration. SS removal efficiencies of around 75% were achieved in the dual Kaldnes primary filter at around 20 m/h without any chemical addition and around 85% at low dosage (1-2 mg/l) of a high MW cationic polymer FO4440SH. In the latter case COD was removed by around 70%. Further experiments were carried out on a multi-media Kaldnes-Filtralite-Sand (KFS) filter for enhanced primary treatment as well as for secondary filtration directly downstream of a high-rate moving bed biofilm reactor, resulting in an extremely compact secondary treatment process. The secondary KFS-filter gave SS-removal efficiencies around 90% (effluent SS < 15 mg/l) and filter run times of around 24 hrs at filtration rates of 10 m/h (sludge loading rates of around 1 kg /m2h) when a small dose (2 mg/l) of polymer was used. It is also demonstrated that the primary filter may also be utilised as a pre-denitrification reactor. A denitrification rate of 1.5 kg NO3-Nequiv./m3d was achieved when the filter was operated at a filtration rate of 5 m/h.

Design criteria of underflow baffles for control of floatables

1998 ◽  
Vol 38 (10) ◽  
pp. 57-63 ◽  
Author(s):  
J. Cigana ◽  
G. Lefebvre ◽  
C. Marche ◽  
M. Couture
Keyword(s):  
Preliminary Analysis ◽  
Pilot Scale ◽  
Design Criteria ◽  
Efficient Design ◽  
Combined Sewer Overflows ◽  
Combined Sewer ◽  
Sewer Overflows

Underflow baffles have gained in popularity over the last few year as a viable means to intercept floatables in Combined Sewer Overflows (CSOs). This has happened although the efficiency of underflow baffles has never been clearly proven. Furthermore, there are no guidelines helping planners in the correct and efficient design of underflow baffles. This article proposes design criteria deduced from pilot scale essays performed in a 17 meters basin at various flowrates. These new informations can be used in two different ways. First, these criteria can be used to correctly design a new overflow chamber. Secondly, these criteria can be used to evaluate the efficiency of existing overflow chambers. Preliminary analysis of existing chambers show that interception efficiency of floatables can be very low.

Effect of organic loading rate on a wastewater treatment process combining moving bed biofilm and membrane reactors

2005 ◽  
Vol 51 (6-7) ◽  
pp. 421-430 ◽  
Author(s):  
E. Melin ◽  
T. Leiknes ◽  
H. Helness ◽  
V. Rasmussen ◽  
H. Ødegaard
Keyword(s):  
Membrane Fouling ◽  
Loading Rate ◽  
Biofilm Reactor ◽  
Cod Removal ◽  
High Rate ◽  
Organic Loading Rate ◽  
Membrane Pore ◽  
Moving Bed ◽  
Loading Rates ◽  
Removal Efficiencies

The effect of moving bed biofilm reactor (MBBR) loading rate on membrane fouling rate was studied in two parallel units combining MBBR and membrane reactor. Hollow fiber membranes with molecular weight cut-off of 30 kD were used. The HRTs of the MBBRs varied from 45 min to 4 h and the COD loading rates ranged from 4.1 to 26.6 g COD m−2 d−1. The trans-membrane pressure (TMP) was very sensitive to fluxes for the used membranes and the experiments were carried out at relatively low fluxes (3.3–5.6 l m−2 h−1). Beside the test with the highest flux, there were no consistent differences in fouling rate between the low- and high-rate reactors. Also, the removal efficiencies were quite similar in both systems. The average COD removal efficiencies in the total process were 87% at 3–4 h HRT and 83% at 0.75–1 h HRT. At high loading rates, there was a shift in particle size distribution towards smaller particles in the MBBR effluents. However, 79–81% of the COD was in particles that were separated by membranes, explaining the relatively small differences in the removal efficiencies at different loading rates. The COD fractionation also indicated that the choice of membrane pore size within the range of 30 kD to 0.1 μm has very small effect on the COD removal in the MBBR/membrane process, especially with low-rate MBBRs.

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