Treatment of Combined Sewer Overflows at Small Wastewater Treatment Works by Constructed Reed Beds

1999 ◽  
Vol 40 (3) ◽  
pp. 357-364 ◽  
Author(s):  
M. B. Green ◽  
J. R. Martin ◽  
P. Griffin
Keyword(s):  
Wastewater Treatment ◽  
Sewage Treatment ◽  
Aggregate Data ◽  
High Rate ◽  
Storm Events ◽  
Tertiary Treatment ◽  
Combined Sewer Overflows ◽  
Reed Beds ◽  
Combined Sewer ◽  
Reed Bed

The performance of constructed reed beds is illustrated by examination of results of surveys from a sewage treatment works with storm treatment reed beds and another site with a combined storm and tertiary treatment reed bed. During surveys of the first system the average hydraulic loads were between 25 and 40 cm d−1 and removals of between 6.7 to 15.4 g m−2 d BOD5, 17.7 to 38.6 g m−2 d TSS, 0.43 to 0.99 g m−2 d NH4N and 0.63 to 0.76 g m−2 d TON were observed. A survey during a storm at the combined storm and tertiary treatment reed bed showed a hydraulic loading of 98 cm d−1 in the first 24 hr and removals of 12.6 g m−2 d BOD5, 29.9 g m−2 d TSS, 0.49 g m−2 d NH4N and a small increase in TON. The sustainability of the high rate of removal during storm events is ascribed to the longer intervals in which loadings are much lower. Samples taken by the regulator from the time of commissioning of 20 sites with combined storm and tertiary treatment reed beds, up to the end of May 1998 are examined. Three of these had operational problems not associated with storm treatment. The aggregate data for the remaining 17 sites (n=906 to 911) illustrate a level of performance matching that of sites with tertiary treatment systems, with averages of 2.2 mg l−1 BOD5, 3.0 mg l−1 TSS, 1.25 mg l−1 NH4N and 12.2 mg l−1 TON.

Implementation of Hamilton-Wentworth Region’s Pollution Control Plan

1996 ◽  
Vol 31 (3) ◽  
pp. 453-472 ◽  
Author(s):  
M. Stirrup
Keyword(s):  
Wastewater Treatment ◽  
Pollution Control ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Control Measures ◽  
Storm Events ◽  
Combined Sewer Overflows ◽  
Control Plan ◽  
Combined Sewer ◽  
Sewer Overflows

Abstract The Regional Municipality of Hamilton-Wentworth operates a large combined sewer system which diverts excess combined sewage to local receiving waters at over 20 locations. On average, there are approximately 23 combined sewer overflows per year, per outfall. The region’s Pollution Control Plan, adopted by Regional Council in 1992, concluded that the only reasonable means of dealing with large volumes of combined sewer overflow in Hamilton was to intercept it at the outlets, detain it and convey it to the wastewater treatment plant after the storm events. The recommended control strategy relies heavily on off-line storage, with an associated expansion of the Woodward Avenue wastewater treatment plant to achieve target reductions of combined sewer overflows to 1–4 per year on average. The region has begun to implement this Pollution Control Plan in earnest. Three off-line detention storage tanks are already in operation, construction of a fourth facility is well underway, and conceptual design of a number of other proposed facilities has commenced. To make the best possible use of these facilities and existing in-line storage, the region is implementing a microcomputer-based real-time control system. A number of proposed Woodward Avenue wastewater treatment plant process upgrades and expansions have also been undertaken. This paper reviews the region's progress in implementing these control measures.

The advantages of a constructed reed bed based strategy for small sewage treatment works

1998 ◽  
Vol 38 (3) ◽  
pp. 143-150
Author(s):  
P. Griffin ◽  
C. Pamplin
Keyword(s):  
Sewage Treatment ◽  
Stormwater Treatment ◽  
Tertiary Treatment ◽  
Environmental Benefit ◽  
Water Utility ◽  
Reed Beds ◽  
Effluent Quality ◽  
Downward Pressure ◽  
Reed Bed ◽  
Treatment Use

The advantages of the use by a major UK water utility serving 8 million people in central England of constructed subsurface flow reed beds for secondary, tertiary and storm water treatment at small sewage treatment works is placed in context with improved permit compliance to more stringent standards and a continuing downward pressure on operating costs. Capital and energy costs are compared with the competing tertiary treatment process of recirculating sand filtration. Further economic advantage is gained by combining tertiary treatment and stormwater treatment. With over 160 sites in operation by mid 1997 the success of the strategy has given confidence to allow for the early or emergency installation of reed beds to improve or maintain effluent quality before replacement, or in one case the provision, of secondary treatment. Use of constructed reed beds is now being extended to larger facilities where only a proportion of the flow needs to be treated to achieve standards. For tertiary treatment reed beds there is an additional environmental benefit with the typical removal of 10.7 mg/l of total nitrogen.

scholarly journals A review of combined sewer overflows as a source of wastewater-derived emerging contaminants in the environment and their management

2021 ◽  
Author(s):  
Bruce Petrie
Keyword(s):  
Wastewater Treatment ◽  
Illicit Drugs ◽  
Emerging Contaminants ◽  
Treatment Strategies ◽  
Storm Events ◽  
Combined Sewer Overflows ◽  
Untreated Wastewater ◽  
Combined Sewer ◽  
Sewer Overflows ◽  
The Impact

AbstractEmerging contaminants such as pharmaceuticals, illicit drugs and personal care products can be released to the environment in untreated wastewater/stormwater mixtures following storm events. The frequency and intensity of combined sewer overflows (CSOs) has increased in some areas due to increasing urbanisation and climate change. Therefore, this review provides an up-to-date overview on CSOs as an environmental source of emerging contaminants. Other than compounds with high removal, those chiral species subject to enantioselective changes (i.e. degradation or inversion) during wastewater treatment can be effective markers of CSO discharge in the environment. A proposed framework for the selection of emerging contaminants as markers of CSOs is outlined. Studies have demonstrated that CSOs can be the main source of emerging contaminants with high removal efficiency during wastewater treatment (e.g. > 90%). However, the impact of CSOs on the environment is location specific and requires decision-making on their appropriate management at catchment level. This process would be aided by further studies on CSOs which incorporate the monitoring of emerging contaminants and their effects in the environment with those more routinely monitored pollutants (e.g. pathogens and priority substances). Mitigation and treatment strategies for emerging contaminants in CSOs are also discussed.

Danish Experience with Emergent Hydrophyte Treatment Systems (EHTS) and Prospects in the Light of Future Requirements on Outlet Water Quality

1990 ◽  
Vol 22 (3-4) ◽  
pp. 65-72 ◽  
Author(s):  
H.-H. Schierup ◽  
H. Brix
Keyword(s):  
Wastewater Treatment ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Reed Beds ◽  
Effluent Quality ◽  
Multi Stage ◽  
Run Off ◽  
Stage System

Since 1983 approximately 150 full-scale emergent hydrophyte based wastewater treatment plants (reed beds) have been constructed in Denmark to serve small wastewater producers. The development of purification performance for 21 plants representing different soil types, vegetation, and hydraulic loading rates has been recorded. Cleaning efficiencies were typically in the range of 60-80% reduction for BOD, 25-50% reduction for total nitrogen, and 20-40% reduction for total phosphorus. The mean effluent BOD, total nitrogen and total phosphorus concentrations of the reed beds were 19 ± 10, 22 ± 9 and 6.7 ± 3.2 mg/l (mean ± SD), respectively. Thus, the general Danish effluent standards of 8 mg/l for N and 1.5 mg/l for P for sewage plants greater than 5,000 PE cannot be met by the present realised design of EHTS. The main problem observed in most systems is a poor development of horizontal hydraulic conductivity in the soil which results in surface run-off. Since the political demands for effluent quality will be more strict in the future, it is important to improve the performance of small decentral sewage treatment plants. On the basis of experiences from different types of macrophyte based and conventional low-technology wastewater treatment systems, a multi-stage system is suggested, consisting of sedimentation and sand filtration facilities followed by basins planted with emergent and submergent species of macrophytes and algal ponds.

Constructed reed beds: appropriate technology for small communities

1995 ◽  
Vol 32 (3) ◽  
pp. 339-348 ◽  
Author(s):  
M. B. Green ◽  
J. Upton
Keyword(s):  
Sewage Treatment ◽  
Appropriate Technology ◽  
Great Promise ◽  
High Quality ◽  
Reed Beds ◽  
Small Communities ◽  
Operational Information ◽  
Reed Bed ◽  
Small Sites ◽  
Very High

Reed bed treatment is put in the context of a major water company’s need to provide reliable, high quality, effluents from small sewage treatment works whilst seeking to minimise running costs. Design and operational information is given for reed bed applications in Severn Trent Water. Performance details are provided for application to secondary, tertiary and storm overflow treatment. The results give particular confidence in the system’s ability to deliver very high quality effluents when used for tertiary treatment, the company’s biggest application. Reed beds work well against less demanding criteria for secondary treatment at small sites and show great promise for storm overflow treatment.

Small wastewater treatment plants in Flanders (Belgium): standard approach and experiences with constructed reed beds

2000 ◽  
Vol 41 (1) ◽  
pp. 57-63 ◽  
Author(s):  
S. Vandaele ◽  
C. Thoeye ◽  
B. Van Eygen ◽  
G. De Gueldre
Keyword(s):  
Wastewater Treatment ◽  
Removal Efficiency ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Surface Flow ◽  
Limiting Factor ◽  
Vertical Flow ◽  
Reed Beds ◽  
Reed Bed

In Flanders (Belgium) an estimated 15% of the population will never be connected to a central wastewater treatment plant (WWTP). Small WWTPs can be a valuable option. Aquafin bases the decision to build SWWTPs on a drainage area study. To realise an accelerated construction the process choice is made accordingly to a standard matrix, which represents the different technologies in function of the size and the effluent consents. A pilot scale constructed two-stage reed bed is used to optimise the concept of the reed beds. The concept consists of a primary clarifier, two parallel vertical flow reed beds followed by a sub-surface flow reed bed. The removal efficiency of organic pollutants is high (COD: 89%, BOD: 98%). Phosphorus removal is high at the start-up but diminishes throughout the testing period (from 100% to 71% retention after 7 months). Nitrogen removal amounts to 53% on average. Nitrification is complete in summer. Denitrification appears to be the limiting factor. In autumn leakage of nitrogen is assumed. Removal efficiency of pathogens amounts to almost 99%. Clogging forms a substantial constraint of the vertical flow reed bed. Problems appear to be related with presettlement, feed interval and geotextile.

The Prediction of Combined Sewer Overflow Performance from Models – A Case Study

1994 ◽  
Vol 29 (1-2) ◽  
pp. 373-382 ◽  
Author(s):  
Peter D. Hedges
Keyword(s):  
Storm Events ◽  
Operating Characteristics ◽  
Combined Sewer Overflows ◽  
Model Studies ◽  
Original Proposal ◽  
Model Study ◽  
Storm Flow ◽  
Combined Sewer ◽  
The Uk ◽  
Main Programme

Hydrodynamic separators have been employed as combined sewer overflows (CSOs) in the UK since the early 1960s. Since little was known of their operating characteristics, Severn Trent Water Authority contracted Aston University to monitor the performance of a separator constructed during 1986-87 at James Bridge, Walsall, UK. Unfortunately only three overflow events were fully documented during the monitoring period, which was particularly dry. One separator was therefore artificially charged by pumping from the adjacent river to simulate storm flow conditions. A model study was not included in the original proposal, but one was established to complement the main programme since the characteristics of hydrodynamic separators were poorly understood. The arrangement of the field site is described, and the results from the monitored storm events, pump tests and model studies are summarised. Characteristics derived from the model study are combined with sewage settling velocity grading curves to predict the performance of the prototype hydrodynamic separator for one of the observed storm events. Given the limitations inherent in the sewage data used, a comparison of the predicted and observed separator efficiencies demonstrates the potential of this approach for the design and selection of CSOs for specific locations.

Reed beds: constructed wetlands for municipal wastewater treatment plant sludge dewatering

2001 ◽  
Vol 44 (11-12) ◽  
pp. 393-398 ◽  
Author(s):  
J.S. Begg ◽  
R.L. Lavigne ◽  
P.L.M. Veneman
Keyword(s):  
Wastewater Treatment ◽  
Total Phosphorus ◽  
Biochemical Oxygen Demand ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Total Suspended Solids ◽  
Sludge Dewatering ◽  
Sludge Treatment ◽  
Reed Beds ◽  
Reed Bed

Reed beds are an alternative technology wastewater treatment system that mimic the biogeochemical processes inherent in natural wetlands. The purpose of this project was to determine the effectiveness of a reed bed sludge treatment system (RBSTS) in southern New England after a six-year period of operation by examining the concentrations of selected metals in the reed bed sludge biomass and by determining the fate of solids and selected nutrients. Parameters assessed in both the reed bed influent and effluent: total suspended solids, biochemical oxygen demand, nitrate-nitrogen and total phosphorus. In addition, the following metals were studied in the reed bed influent, effluent and Phragmites plant tissue and the sludge core biomass: boron, cadmium, chromium, copper, iron, lead, manganese, molybdenum, nickel, and zinc. The removal efficiencies for sludge dewatering, total suspended solids and biochemical oxygen demand were all over 90%. Nitrate and total phosphorus removal rates were 90% and 80% respectively. Overall metals removal efficient was 87%. Copper was the only metal in the sludge biomass that exceeded the standards set by the Massachusetts Department of Environmental Protection for land disposal of sludge. The highest metal concentrations, for the most part, tended to be in the lower tier of the sludge profile. The exception was boron, which was more concentrated in the middle tier of the sludge profile. The data and results presented in this paper support the notion that reed bed sludge treatment systems and the use of reed beds provide an efficient and cost effective alternative for municipal sludge treatment.

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