Evaluation of sludge dewatering reed beds: a niche for small systems

1997 ◽  
Vol 35 (6) ◽  
pp. 21-28 ◽  
Author(s):  
B. J. Kim ◽  
E. D. Smith

The U.S. Army Construction Engineering Research Laboratories (USACERL) has been developing and adopting improved sludge dewatering systems for U.S. Army wastewater treatment plants. USACERL selected reed beds as the best alternative for future Army sludge dewatering systems based on the system's economical and technical feasibility and on a demonstration of the technology at Fort Campbell, KY, USA. This paper compares the Army's options for upgrading Fort Campbell's sand-drying beds, analyzes costs, discusses sludge hydraulic and solids loading rate data from existing reed bed operations in the United States, and presents 5 years' operational data from Fort Campbell. Options considered for comparison included: land application of sludge at training fields, wedgewater beds, vacuum-assisted beds, wedgewater beds and composting, mechanical dewatering systems, and a “no change” option in which sand-drying beds would have been retained. In conclusion, this paper summarizes advantages and limitations of reed bed sludge dewatering. Advantages of reed beds may include: low investment especially when sand-drying beds are converted to reed beds, savings of sludge removal costs, and the benefits inherent to using a simple and economical technology. Limitations may include: large land requirements and little scientific understanding of this empirical technology. The challenge will be to further develop appropriate disposal technologies to meet new U.S. sludge regulations.

2015 ◽  
Vol 71 (9) ◽  
pp. 1286-1292 ◽  
Author(s):  
Steen Nielsen

The effect on the environment of the establishment and operation of a sludge treatment reed bed system (STRB) is quite limited compared to mechanical sludge dewatering, with its accompanying use of energy and chemicals. The assessment presented here of the investment, operation and maintenance costs of a typical STRB, and of the related environmental impact, is based on the experiences gained from the operation of a large number of STRB in Denmark. There are differences in the environmental perspectives and costs involved in mechanical sludge dewatering and disposal on agricultural land compared to STRB. The two treatment methods were considered for comparison based on a treatment capacity of 550 tons of dry solids per year and with land application of the biosolids in Denmark. The initial capital cost for STRB is higher than a conventional mechanical system; however, an STRB would provide significant power and operating-cost savings, with a significant saving in the overall cost of the plant over 20–30 years. The assessment focuses on the use of chemicals, energy and greenhouse gas emissions and includes emptying, sludge residue quality and recycling. STRB with direct land application is the most cost-effective scenario and has the lowest environmental impact. A sludge strategy consisting of an STRB will be approximately DKK 536,894–647,636 cheaper per year than the option consisting of a new screw press or decanter.


2000 ◽  
Vol 41 (1) ◽  
pp. 57-63 ◽  
Author(s):  
S. Vandaele ◽  
C. Thoeye ◽  
B. Van Eygen ◽  
G. De Gueldre

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.


2001 ◽  
Vol 44 (11-12) ◽  
pp. 393-398 ◽  
Author(s):  
J.S. Begg ◽  
R.L. Lavigne ◽  
P.L.M. Veneman

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.


2003 ◽  
Vol 48 (5) ◽  
pp. 111-117 ◽  
Author(s):  
H. Obarska-Pempkowiak ◽  
A. Tuszyńska ◽  
Z. Sobociński

Macrophyte plants e.g. reed, cattails, bulrush, can be applied to sewage sludge utilisation. One of the first facilities of this type in the Gdansk region (Northern Poland) was established in Darzlubie in 1995 and primary sludge has been utilised in reed beds there. The objective of the undertaken research was evaluating the influence of sewage sludge storage on its chemical and biological properties. A total of 5.5 m thick layer of primary, anaerobically stabilised sludge (moisture 90-96%) was loaded to the reed bed during 6 years of operation. As a consequence of dewatering and biochemical transformation, the sludge layer decreased to 30 cm. Moisture, organic matter, total nitrogen and total phosphorus contents, as well as coli index, Clostridium perfringens index and the number of Ascaris lumbricoides ova were measured. Also the contents of heavy metals (Cu, Pb, Zn, Ni, Cr and Cd) were determined in sludge samples. The study showed that sludge storage in reed beds results in dewatering and partial stabilisation. In the reed lagoons in Swarzewo and Zambrow, dewatering of secondary sludges was investigated. The results of measurements of the quality of sludge and effluent from the reed lagoon in Zambrow are also presented.


2000 ◽  
Vol 41 (1) ◽  
pp. 65-68 ◽  
Author(s):  
W. Zwara ◽  
H. Obarska-Pempkowiak

The problem of utilization and management of sewage sludge originating from small wastewater treatment plants is still unsolved in Poland. One of the waste-free technologies of sludge utilization is the reed bed method. Two experimental facilities of this type have been operating for four years in the Gdansk Region: a reed bed in Darżlubie and a reed lagoon in Swarzewo. The investigation was aimed at evaluating the influence of the storage on chemical and biological properties of sewage sludge deposited in beds. Tests were carried out in the period of two years. Moisture, organic matter, total nitrogen and total phosphorus contents as well as coli index, Clostridium perfringens index and number of Ascaris lumbricoides eggs analyzes were measured. Analyses of contents of heavy metals Cu, Pb, Ni, Zn, Cr and Cd for sludge samples from Darżlubie were additionally carried out. Tests proved that the utilization of sludge in reed beds allows using the end product as a fertilizer in agriculture. The most important problem is increasing of heavy metals content and number of Ascaris lumbricoides per mass of sludge during long time storage.


1990 ◽  
Vol 22 (3-4) ◽  
pp. 65-72 ◽  
Author(s):  
H.-H. Schierup ◽  
H. Brix

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.


1995 ◽  
Vol 32 (3) ◽  
pp. 339-348 ◽  
Author(s):  
M. B. Green ◽  
J. Upton

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.


1993 ◽  
Vol 28 (10) ◽  
pp. 1-8 ◽  
Author(s):  
A. Gaber ◽  
M. Antill ◽  
W. Kimball ◽  
R. Abdel Wahab

The implementation of urban village wastewater treatment plants in developing countries has historically been primarily a function of appropriate technology choice and deciding which of the many needy communities should receive the available funding and priority attention. Usually this process is driven by an outside funding agency who views the planning, design, and construction steps as relatively insignificant milestones in the overall effort required to quickly better a community's sanitary drainage problems. With the exception of very small scale type sanitation projects which have relatively simple replication steps, the development emphasis tends to be on the final treatment plant product with little or no attention specifically focused on community participation and institutionalizing national and local policies and procedures needed for future locally sponsored facilities replication. In contrast to this, the Government of Egypt (GOE) enacted a fresh approach through a Local Development Program with the United States AID program. An overview is presented of the guiding principals of the program which produced the first 24 working wastewater systems including gravity sewers, sewage pumping stations and wastewater treatment plants which were designed and constructed by local entities in Egypt. The wastewater projects cover five different treatment technologies implemented in both delta and desert regions.


Pathogens ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 798
Author(s):  
Samendra P. Sherchan ◽  
Shalina Shahin ◽  
Jeenal Patel ◽  
Lauren M. Ward ◽  
Sarmila Tandukar ◽  
...  

In this study, we investigated the occurrence of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) RNA in primary influent (n = 42), secondary effluent (n = 24) and tertiary treated effluent (n = 34) collected from six wastewater treatment plants (WWTPs A–F) in Virginia (WWTP A), Florida (WWTPs B, C, and D), and Georgia (WWTPs E and F) in the United States during April–July 2020. Of the 100 wastewater samples analyzed, eight (19%) untreated wastewater samples collected from the primary influents contained SARS-CoV-2 RNA as measured by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) assays. SARS-CoV-2 RNA were detected in influent wastewater samples collected from WWTP A (Virginia), WWTPs E and F (Georgia) and WWTP D (Florida). Secondary and tertiary effluent samples were not positive for SARS-CoV-2 RNA indicating the treatment processes in these WWTPs potentially removed SARS-CoV-2 RNA during the secondary and tertiary treatment processes. However, further studies are needed to understand the log removal values (LRVs) and transmission risks of SARS-CoV-2 RNA through analyzing wastewater samples from a wider range of WWTPs.


2021 ◽  
Vol 13 (4) ◽  
pp. 1618
Author(s):  
Anneliese Dyer ◽  
Amelia Christine Miller ◽  
Brianna Chandra ◽  
Juan Galindo Maza ◽  
Carley Tran ◽  
...  

With traditional natural gas being one of the top options for heating in the United States and the present threat of climate change, there is a demand for an alternative clean fuel source. A Renewable Natural Gas Implementation Decision-Making Conceptual Model was created to provide a framework for considering the feasibility of renewable natural gas (RNG) projects and applied to New Jersey, specifically investigating landfills and wastewater treatment plants (WWTPs). Data from the US EPA’s Landfill Methane Outreach Program and New Jersey’s Department of Environmental Protection Sewage Sludge databases were used to identify seven landfills and 22 WWTPs as possible locations for RNG projects. Landfills were found to have a higher potential for producing RNG, on average potentially producing enough RNG to heat 12,792 homes per year versus 1227 for the average WWTP. Additionally, landfills, while having higher capital expenses, have lower projected payback periods, averaging 5.19 years compared to WWTP’s 11.78 years. WWTPs, however, generally are located closer to existing natural gas pipelines than landfills and when they produce more than 362 million standard cubic feet per year (MMSCFY) of biogas are financially feasible. RNG projects at Monmouth County Reclamation Center, Ocean County Landfill, and Passaic Valley Sewerage Commission WWTP show the greatest potential. Greenhouse gas emission reductions from RNG projects at these facilities utilizing all available biogas would be 1.628 million metric tons CO2 equivalents per year, synonymous to removing over 351,000 passenger vehicles from the road each year. In addition, expanding federal and state incentives to encompass RNG as a heating fuel is necessary to reduce financial barriers to RNG projects throughout the US. Overall, this paper supports the hypothesized conceptual model in examining the feasibility of RNG projects through examples from New Jersey and confirms the potential for RNG production utilizing existing waste streams.


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