Unexpected declines in stream phosphorus concentrations across southern Ontario

2014 ◽  
Vol 71 (3) ◽  
pp. 337-342 ◽  
Author(s):  
Shanel M. Raney ◽  
M. Catherine Eimers
Keyword(s):  
Municipal Wastewater ◽  
Agricultural Land ◽  
Wastewater Treatment Plants ◽  
Municipal Wastewater Treatment ◽  
Southern Ontario ◽  
Treated Effluent ◽  
Time Period ◽  
Long Term Trends ◽  
Municipal Wastewater Treatment Plants ◽  
Almost All

Long-term trends (1975–2010) in total phosphorus (TP) concentrations were evaluated at 113 stream stations across southern Ontario. Declines in TP were evident at the majority of sites (68%), including those both with (n = 49) and without (n = 64) upstream municipal wastewater treatment plants (MWWTP). Although declines in TP at stream stations downstream of MWWTPs may be attributed to improvements in P removal from treated effluent, declines at the remaining streams must be attributed to other causes. During the same time period, increases in chloride (Cl−) were observed at almost all (95%) of the 64 MWWTP-free stations. Over the past 35 years, urban land cover has increased at the expense of agricultural land area in Ontario, with the majority of these changes occurring in southern Ontario. The coincidence of declines in TP and increases in Cl− at the 64 MWWTP-free streams suggests that the two may be related, with P-rich agricultural fields being replaced with impervious surfaces and therefore increased road salt applications.

scholarly journals Investigating the effects of different cationic charge flocculation polymers on municipal wastewater sludge dewatering

2021 ◽  
Author(s):  
Megan Abrahams ◽  
Mujahid Aziz ◽  
Godwill Kasongo
Keyword(s):  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Operating Cost ◽  
Wastewater Sludge ◽  
Municipal Wastewater Treatment ◽  
Bench Scale ◽  
Treated Effluent ◽  
Solids Concentration ◽  
Municipal Wastewater Treatment Plants ◽  
Polymer Flocculant

Abstract The minimization of sludge produced by municipal wastewater treatment plants (MWWTPs) is critical as its handling accounts for approximately 50% of the total operating cost. The challenges in predicting dewatering performance can be overcome by optimizing the sludge treatment process, especially conditioning and dewatering. This study aimed to investigate sludge dewaterability at four different MWWTPs, using a gravity drainage test unit and a bench-scale press. The effect of differently treated effluent used as a solvent to mix the flocculation polymers was observed during dewatering. The membrane bioreactor (MBR) treated effluent yielded the highest filtrate volume in the lowest amount of time, with the least polymer flocculant dosage. The Box Behnken Design model fitted the data and proved a relationship between polymer dosage, cake solids concentration, and cake height during the bench-scale press tests.

scholarly journals Heavy metal content of Swedish municipal wastewater sludge – status and goals

2017 ◽  
Vol 76 (4) ◽  
pp. 869-876 ◽  
Author(s):  
A. Mattsson ◽  
A. Finnson ◽  
D. I'Ons
Keyword(s):  
Heavy Metal ◽  
Municipal Wastewater ◽  
Agricultural Land ◽  
Wastewater Treatment Plants ◽  
Arable Land ◽  
Wastewater Sludge ◽  
Municipal Wastewater Treatment ◽  
Municipal Wastewater Treatment Plants ◽  
Source Management

In 2014, 25% of the sludge produced at Swedish municipal wastewater treatment plants was applied to agricultural land. Even though the Swedish heavy metal limits for sludge to be used in agriculture are amongst the most stringent in the EU, more stringent heavy metal limits are proposed. Most sludge applied to agricultural land is recycled within a certification system, Revaq. Revaq has targets for control at source management and improvement of sludge quality. Statistics based on data collected within the Revaq system was used to differentiate between local and general sources of heavy metals and assess the need to improve sludge quality. The analysis indicates that proposed future national limits on the quality of the sludge can be met by most of the sludge. The improvement needed for about 20% of the sludge is feasible through local control at source management. The levels of cadmium, copper and mercury need to be reduced if these metals are not to limit the amount of sludge that may be applied per unit area of arable land. Finally, the long term Revaq targets for cadmium and silver will be difficult to meet.

A study about the use of chemicals in conventional tertiary treatment. Performances comparison of three municipal wastewater treatment plants and pilot plant experiences

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
A. Iborra-Clar ◽  
J.A. Mendoza-Roca ◽  
A. Bes-Pií ◽  
J.J. Morenilla-Martínez ◽  
I. Bernácer-Bonora ◽  
...  
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Pilot Plant ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Secondary Effluent ◽  
Municipal Wastewater Treatment ◽  
Wastewater Reclamation ◽  
Valencian Region ◽  
Municipal Wastewater Treatment Plants

Rainfall diminution in the last years has entailed water scarcity in plenty of European regions, especially in Mediterranean areas. As a consequence, regional water authorities have enhanced wastewater reclamation and reuse. Thus, the implementation of tertiary treatments has become of paramount importance in the municipal wastewater treatment plants (WWTP) of Valencian Region (Spain). Conventional tertiary treatments consist of a physico-chemical treatment of the secondary effluent followed by sand filtration and UV radiation. However, the addition of coagulants and flocculants sometimes does not contribute significantly in the final water quality. In this work, results of 20-months operation of three WWTP in Valencian Region with different tertiary treatments (two without chemicals addition and another with chemicals addition) are discussed. Besides, experiments with a 2 m3/h pilot plant located in the WWTP Quart-Benager in Valencia were performed in order to evaluate with the same secondary effluent the effect of the chemicals addition on the final water quality. Results showed that the addition of chemicals did not improve the final water quality significantly. These results were observed both comparing the three full scale plants and in the pilot plant operation.

Nanofiltration of endocrine disrupting compounds

2003 ◽  
Vol 3 (5-6) ◽  
pp. 321-327 ◽  
Author(s):  
M. Gallenkemper ◽  
T. Wintgens ◽  
T. Melin
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Endocrine Disrupting Compounds ◽  
Municipal Wastewater Treatment ◽  
Water And Wastewater Treatment ◽  
Wide Range ◽  
Endocrine Disrupting ◽  
Municipal Wastewater Treatment Plants ◽  
Set Up

Endocrine disrupting compounds can affect the hormone system in organisms. A wide range of endocrine disrupters were found in sewage and effluents of municipal wastewater treatment plants. Toxicological evaluations indicate that conventional wastewater treatment plants are not able to remove these substances sufficiently before disposing effluent into the environment. Membrane technology, which is proving to be an effective barrier to these substances, is the subject of this research. Nanofiltration provides high quality permeates in water and wastewater treatment. Eleven different nanofiltration membranes were tested in the laboratory set-up. The observed retention for nonylphenol (NP) and bisphenol A (BPA) ranged between 70% and 100%. The contact angle is an indicator for the hydrophobicity of a membrane, whose influence on the permeability and retention of NP was evident. The retention of BPA was found to be inversely proportional to the membrane permeability.

Experience from 10 Years Advanced Wastewater Treatment – Technology and Results

1982 ◽  
Vol 14 (1-2) ◽  
pp. 121-133
Author(s):  
C Forsberg ◽  
B Hawerman ◽  
B Hultman
Keyword(s):  
Wastewater Treatment ◽  
Urban Population ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Municipal Wastewater Treatment ◽  
Treatment Technology ◽  
Removal Efficiencies ◽  
Municipal Wastewater Treatment Plants ◽  
Operational Modes ◽  
Polluted Waters

Experience from advanced municipal wastewater treatment plants and recovery of polluted waters are described for the last ten years in Sweden. Except in municipalities with large recipients, the urban population is served by treatment plants with combined biological and chemical treatment. Most of these plants are post-precipitation plants. Several modified operational modes have been developed in order to improve the removal efficiencies of pollutants and to reduce the costs. Results are presented on the recovery of specially investigated lakes with a lowered supply of total phosphorus and organic matter.

scholarly journals Production and Destination of Sewage Sludge in the Piemonte Region (Italy): The Results of a Survey for a Future Sustainable Management

2021 ◽  
Vol 18 (7) ◽  
pp. 3556
Author(s):  
Giuseppe Campo ◽  
Alberto Cerutti ◽  
Claudio Lastella ◽  
Aldo Leo ◽  
Deborah Panepinto ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Sustainable Management ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Similar Amount ◽  
Municipal Wastewater Treatment ◽  
Sludge Management ◽  
Subsequent Step ◽  
German Legislation ◽  
Municipal Wastewater Treatment Plants

The management of sewage sludge originated from municipal wastewater treatment plants (WWTPs) is an urgent issue. In 2019, the local authority of the Piemonte region started a survey with the aim of collecting recent data concerning wastewater and sludge management in the WWTPs located in its own territory. The survey’s results revealed that 60% of the sludge (51,000 t, as dry substance, d.s.) produced by the local WWTPs was recovered or disposed of outside of the region, and a similar amount of sludge was recovered in agriculture directly or after composting. The increase in the costs to accommodate sewage sludge in recovery or disposal plants, followed to a recent Italian Sentence (27958/2017), and the more and more stringent requirements fixed by lots of European countries for the application of sludge in agriculture, are pushing the Piemonte region authority to re-organize its own network for sludge management, with solutions based onto proximity and diversification. Whether the provisions of the current German legislation are applied in the future also in Italy, approx. 90% of sewage sludge produced into the Piemonte region should be incinerated, with a subsequent step of phosphorous recovery. The new regional plan, according to the Regional Address Deed, should consider a diversification of sludge treatment and recovery practices. On this basis, a need for new plants for around 40,000 t d.s./y could be planned.

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