Biorefinery potential of chemically enhanced primary treatment sewage sludge to representative value-added chemicals - a de novo angle for wastewater treatment

2021 ◽  
pp. 125583
Author(s):  
Houde Jing ◽  
Huaimin Wang ◽  
Carol Sze Ki Lin ◽  
Huichuan Zhuang ◽  
Ming Ho To ◽  
...  
2016 ◽  
Vol 74 (2) ◽  
pp. 438-447 ◽  
Author(s):  
J. Väänänen ◽  
M. Cimbritz ◽  
J. la Cour Jansen

Primary and chemically enhanced primary wastewater treatment with microsieving (disc or drum filtration) was studied at the large pilot scale at seven municipal wastewater treatment plants in Europe. Without chemical dosing, the reduction of suspended solids (SS) was (on average) 50% (20–65%). By introducing chemically enhanced primary treatment and dosing with cationic polymer only, SS removal could be controlled and increased to >80%. A maximum SS removal of >90% was achieved with a chemical dosing of >0.007 mg polymer/mg influent SS and 20 mg Al3+/L or 30 mg Fe3+/L. When comparing sieve pore sizes of 30–40 μm with 100 μm, the effluent SS was comparable, indicating that the larger sieve pore size could be used due to the higher loading capacity for the solids. Phosphorus removal was adjusted with the coagulant dose, and a removal of 95–97% was achieved. Moreover, microsieving offers favourable conditions for automated dosing control due to the low retention time in the filter.


Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1246
Author(s):  
Aleš Paulu ◽  
Jan Bartáček ◽  
Markéta Šerešová ◽  
Vladimír Kočí

Alternative wastewater treatment (WWT) technologies with lower environmental impacts seem to be the way forward in the pursuit of sustainable wastewater treatment plants (WWTPs). Process modelling of material and energy flows together with life-cycle assessment (LCA) can help to better understand these impacts and show the right direction for their development. Here, we apply this combined approach to three scenarios: conventional WWT; conventional WWT + chemically enhanced primary treatment (CEPT); conventional WWT + CEPT + side stream partial nitritation/anammox (PN/A). For each scenario, equations were developed to calculate chemical oxygen demand and nitrogen flow (solid and dissolved form) through the WWTP and to estimate the energy demands of its unit operations. LCA showed that the main environmental impact categories for all scenarios were global warming potential (GWP), eutrophication potential (EP) and marine aquatic eco-toxicity potential (MAETP). Compared with conventional WWT, CEPT and CEPT combined with PN/A resulted in a higher sum of normalized and weighed environmental indicators, by 19.5% and 16.4%, respectively (20.0% and 18.3% including biogenic carbon). Interestingly, the environmentally positive features of the alternative scenarios were often traded-off against other increased negative impacts. This suggests that further development is needed to consider these technologies a sustainable alternative.


2021 ◽  
Vol 11 (3) ◽  
pp. 3917-3926

A techno-economic analysis was performed to investigate wastewater treatment feasibility using chemically enhanced primary treatment (CEPT) compared to conventional primary treatment (PT). An experimental study was conducted to investigate the performance of CEPT at optimum conditions, and experimental results were used to feed the techno-economical study with required input data. The wastewater treatment was focused on reducing BOD5, COD, and TSS. The comparison between CEPT and PT was concerned with removal efficiency and process economics. CEPT process has shown better efficiency compared to PT process. The experimental work indicated that ferric chloride is the optimum coagulant agent since it is highly efficient and available at a low cost. The optimum coagulant experimental results showed that the turbidity removal efficiency was 82%, COD removal 84%, BOD removal 68.1%, and SS removal 85%. The techno-economic study was performed to investigate the feasibility of CEPT. The techno-economic evaluation indicated that CEPT is a cost-effective and technically viable process for wastewater treatment. The techno-economic evaluation indicated that CEPT is a cost-effective and technically viable process for wastewater treatment as the operating cost can be reduced by 66% compared to PT.


2002 ◽  
Vol 39 (5) ◽  
pp. 1139-1149 ◽  
Author(s):  
Irene M.C Lo ◽  
W W Zhou ◽  
K M Lee

The disposal of increased quantities of dewatered sewage sludge to landfills may cause geoenvironmental problems such as leachability, total and differential settlement, and slope stability of the waste during disposal. This study investigates the geotechnical properties of the dewatered sewage sludge generated from chemically enhanced primary treatment (CEPT) in Hong Kong. Compaction test results show that CEPT sludge exhibits compaction characteristics similar to those of clayey soils; however, the lowest hydraulic conductivity of CEPT sludge does not occur near the wet side of its optimum water content. The consolidation behavior of CEPT sludge does not follow the conventional Terzaghi's theory. Under an overburden pressure higher than 24 kPa, the relationship between the logarithm of the hydraulic conductivity (logk) and the void ratio (e) is linear. Results from direct shear tests reveal that, for CEPT sludge, slopes of 20° can probably be constructed during the landfill operation without causing sliding problems. Compared with the disposal of pure CEPT sludge, the co-disposal of dewatered sewage sludge with other solid wastes commonly found in Hong Kong results in lower compressibility, smaller settlement, but higher hydraulic conductivity.Key words: co-disposal, geotechnical properties, landfill disposal, sewage sludge.


2009 ◽  
Vol 60 (7) ◽  
pp. 1803-1809 ◽  
Author(s):  
Hongtao Wang ◽  
Fengting Li ◽  
Arturo A. Keller ◽  
Ran Xu

With Chemically Enhanced Primary Treatment (CEPT) as the short-term process, the capacity of Bailonggang Wastewater Treatment Plant accounts for almost 25% of the total capacity of wastewater treatment in Shanghai, China. However, shortly after this plant was placed in operation in 2004, it was found that the effluent of CEPT couldn't meet the new national discharge criteria. Although the removal of phosphate is almost 80%, chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) in the effluent is frequently found to exceed the standards. The primary goal of this research is to investigate the possibility of optimizing the CEPT to make it meet the discharge criteria before it is upgraded to a secondary treatment. An oxidant is adopted to remove NH3-N, and a high performance polyaluminum chloride (HP-PACl) is synthesized to enhance the removal of COD. It is found that HP-PACl improves the removal of COD, and the oxidant enhances NH3-N removal effectively. However, to meet the requirement of a newly implemented stricter discharge standard, it is necessary to upgrade this CEPT to a secondary treatment. The results of this study provide scientific evidence for the upgrade of the Bailonggang Wastewater Treatment Plant.


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