Occurrence of retinoic acids and their metabolites in sewage and their removal efficiencies by chemically enhanced primary treatment and secondary biological treatment

Chemosphere ◽  
2021 ◽  
pp. 130745
Author(s):  
Katie Wan Yee Yeung ◽  
Guang-Jie Zhou ◽  
Yuefei Ruan ◽  
Paul Kwan Sing Lam ◽  
Kenneth Mei Yee Leung
1995 ◽  
Vol 32 (9-10) ◽  
pp. 75-84 ◽  
Author(s):  
A. D. Andreadakis ◽  
G. H. Kristensen ◽  
A. Papadopoulos ◽  
C. Oikonomopoulos

The wastewater from the city of Thessaloniki is discharged without treatment to the nearby inner part of the Thessaloniki Gulf. The existing, since 1989, treatment plant offers only primary treatment and did not operate since the expected effluent quality is not suitable for safe disposal to the available recipients. Upgrading of the plant for advanced biological treatment, including seasonal nitrogen removal, is due from 1995. In the mean time, after minor modifications completed in February 1992, the existing plant was put into operation as a two-stage chemical-biological treatment plant for 40 000 m3 d−1, which corresponds to about 35% of the total sewage flow. The operational results obtained during the two years operation period are presented and evaluated. All sewage and sludge treatment units of the plant perform better than expected, with the exception of the poor sludge settling characteristics, due to severe and persistent bulking caused by excessive growth of filamentous microorganisms, particularly M. Parvicella. Effective control of the bulking problem could lead to more cost-effective operation and increased influent flows.


2018 ◽  
Vol 2018 (18) ◽  
pp. 155-163
Author(s):  
Tulip Chakraborty ◽  
Scott Smith ◽  
Domenico Santoro ◽  
John Walton ◽  
Madhumita B Ray ◽  
...  

2017 ◽  
Vol 75 (11) ◽  
pp. 2598-2606 ◽  
Author(s):  
B. Rusten ◽  
S. S. Rathnaweera ◽  
E. Rismyhr ◽  
A. K. Sahu ◽  
J. Ntiako

Fine mesh rotating belt sieves (RBS) offer a very compact solution for removal of particles from wastewater. This paper shows examples from pilot-scale testing of primary treatment, chemically enhanced primary treatment (CEPT) and secondary solids separation of biofilm solids from moving bed biofilm reactors (MBBRs). Primary treatment using a 350 microns belt showed more than 40% removal of total suspended solids (TSS) and 30% removal of chemical oxygen demand (COD) at sieve rates as high as 160 m³/m²-h. Maximum sieve rate tested was 288 m³/m²-h and maximum particle load was 80 kg TSS/m²-h. When the filter mat on the belt increased from 10 to 55 g TSS/m², the removal efficiency for TSS increased from about 35 to 60%. CEPT is a simple and effective way of increasing the removal efficiency of RBS. Adding about 1 mg/L of cationic polymer and about 2 min of flocculation time, the removal of TSS typically increased from 40–50% without polymer to 60–70% with polymer. Using coagulation and flocculation ahead of the RBS, separation of biofilm solids was successful. Removal efficiencies of 90% TSS, 83% total P and 84% total COD were achieved with a 90 microns belt at a sieve rate of 41 m³/m²-h.


2001 ◽  
Vol 44 (1) ◽  
pp. 33-39 ◽  
Author(s):  
O. Tornes

Norway is a leading country on wastewater treatment comprising chemical precipitation processes. This is because Norwegian effluent standards to the North Sea have traditionally focused on phosphorus removal. In most cases, chemical treatment therefore has been considered to give lower investment and operating costs than biological treatment. Norwegian wastewater policy and management is based on the EU guidelines resulting from the EEA (European Economic Area) Agreement. According to the 1991 Urban Wastewater Treatment Directive, this will in most cases require secondary treatment. However, primary treatment can be accepted for plants larger than 10,000 PT with effluents to less sensitive coastal areas, if no negative environmental impacts can be proved. The main objective of the Regional Water, Sewerage and Waste Company (IVAR) is to comply with the prevailing effluent limits at lowest possible cost. During the past four years, IVAR has therefore undertaken comprehensive optimising of the precipitation process including full-scale experiments with different coagulant dosing control systems and different types of coagulants. IVAR also accomplished a feasibility study of introducing biological treatment as an alternative to chemical treatment. Under the prevailing frame conditions of discharge requirements and sludge deposit costs, it is not economically feasible to change to organic coagulants or biological treatment. This conclusion might have to be altered later resulting from the implementation of new EU regulations and increasing sludge deposit costs. This paper presents results from full-scale experiments, extracts from the feasibility study and a comparison of costs. Furthermore, the practical consequences of implementing the EU-guidelines are discussed.


2015 ◽  
Vol 57 (16) ◽  
pp. 7280-7286 ◽  
Author(s):  
Muhammad Bilal Asif ◽  
Nadeem Majeed ◽  
Sidra Iftekhar ◽  
Rasikh Habib ◽  
Sadia Fida ◽  
...  

2013 ◽  
Vol 464 ◽  
pp. 189-193
Author(s):  
Jun Hong Luo ◽  
Chong Hao Huang ◽  
Yong Zhang

Chemically enhanced primary treatment (CEPT) process have advantages of low pollution load and low costs, it can greatly improve the removal efficiency of organic matter by primary treatment , so the process has been studied widely and intensively. In this thesis, the mechanism, coagulant type, dosage and precipitation time were studied.


Author(s):  
Junwon Park ◽  
Changsoo Kim ◽  
Youngmin Hong ◽  
Wonseok Lee ◽  
Hyenmi Chung ◽  
...  

In this study, we analyzed 27 pharmaceuticals in liquid and solid phase samples collected from the unit processes of four different sewage treatment plants (STPs) to evaluate their distribution and behavior of the pharmaceuticals. The examination of the relative distributions of various categories of pharmaceuticals in the influent showed that non-steroidal anti-inflammatory drugs (NSAIDs) were the most dominant. While the relative distribution of antibiotics in the influent was not high (i.e., 3%–5%), it increased to 14%–30% in the effluent. In the four STPs, the mass load of the target pharmaceuticals was reduced by 88%–95% mainly in the biological treatment process, whereas the ratio of pharmaceuticals in waste sludge to those in the influent (w/w) was only 2%. In all the STPs, the removal efficiencies for the stimulant caffeine, NSAIDs (acetaminophen, naproxen, and acetylsalicylic acid), and the antibiotic cefradine were high; they were removed mainly by biological processes. Certain compounds, such as the NSAID ketoprofen, contrast agent iopromide, lipid regulator gemfibrozil, and antibiotic sulfamethoxazole, showed varying removal efficiencies depending on the contribution of biodegradation and sludge sorption. In addition, a quantitative meta-analysis was performed to compare the pharmaceutical removal efficiencies of the biological treatment processes in the four STPs, which were a membrane bioreactor (MBR) process, sequencing batch reactor (SBR) process, anaerobic–anoxic–oxic (A2O) process, and moving-bed biofilm reactor (MBBR) process. Among the biological processes, the removal efficiency was in the order of MBR > SBR > A2O > MBBR. Among the tertiary treatment processes investigated, powdered activated carbon showed the highest removal efficiency of 18%–63% for gemfibrozil, ibuprofen, ketoprofen, atenolol, cimetidine, and trimethoprim.


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