Effect of mixed liquor suspended solid concentration on nitrous oxide emission from an anoxic/oxic sequencing bioreactor

2019 ◽  
Vol 163 ◽  
pp. 48-56 ◽  
Author(s):  
Xu Yan ◽  
Dongli Guo ◽  
Dezhi Qiu ◽  
Shikan Zheng ◽  
Mengke Jia ◽  
...  
Irriga ◽  
2003 ◽  
Vol 8 (1) ◽  
pp. 78-87 ◽  
Author(s):  
José Euclides Stipp Paterniani ◽  
Marcos Eduardo Scatolini

EFICIÊNCIA DE DIFERENTES ELEMENTOS FILTRANTES NA PREVENÇÃO DE OBSTRUÇÃO DE GOTEJADORES   José Euclides Stipp Paterniani Marcos Eduardo ScatoliniFaculdade de Engenharia Agrícola, Universidade Estadual de Campinas, Campinas, SP. CP 6011, CEP 13083-970, E-mail: [email protected]   1 RESUMO  Durante ensaios para verificação de eficiência de retenção de algas em filtros de discos 120 MESH, tela 120 MESH e manta sintética não tecida, foram avaliados o grau de obstrução de gotejadores de labirinto com fluxo turbulento e vazão nominal de 4 L.h-1 e 8 L.h-1. Para determinação da obstrução causada por impurezas não retidas no meio filtrante foram avaliadas a evolução da vazão e da uniformidade estatística dos gotejadores submetidos aos diferentes meios filtrantes durante um período de 22 semanas durante 4 horas diárias e comparadas com uma parcela testemunha sem elemento filtrante. Os resultados mostraram que houve diferença significativa entre o elemento de discos, que apresentou maior uniformidade estatística, os filtros de manta e tela com valores intermediários e a testemunha que apresentou menor uniformidade estatística. No entanto, para caracterizar de maneira definida a diferença no desempenho dos elementos filtrantes, estes valores deveriam vir acompanhados de uma redução contínua na vazão média dos tratamentos, o que foi observado apenas para o elemento de tela com o gotejador de 4 L.h-1. As demais variações da uniformidade estatística foram temporais, provavelmente devido a obstruções  temporárias ocasionadas por variações da concentração de sólidos suspensos na água de irrigação.  UNITERMOS: Filtragem, Gotejamento, Qualidade da água.   PATERNIANI, J.E.S.; SCATOLINI, M.E. EFFICIENCY OF DIFFERENT FILTER ELEMENTS TO PREVENT TRICKLE CLOGGING   2 ABSTRACT  This work aimed to verify the efficiency of algae removal in disks 120 mesh, screen 120  mesh, and non woven synthetic fabric filters. It was evaluated the degree of clogging of turbulent flow drippers on 4 L.h-1 and 8 L.h-1 outflow. For blockage determination the outflow evolution  and statistics uniformity (Us) of the dripper have been evaluated when submitted to different filter media over 22 weeks, 4 daily hours compared to a control without the filter element. The results indicated significant differences among the elements. The disk element presented greater statistic uniformity. The screen filter and the non woven synthetic fabric element presented intermediate values whereas the parcel with no filter element (control) presented minor statistic uniformity. However, in order to characterize performance differences among them, values should be presented along with a  continuous average outflow reduction in all treatments. This pattern was observed only for the screen filter and 4 L.h-1 drippers. The statistics uniformity variation has been probably caused by temporary blockages due to variation in suspended solid concentration in irrigation water.  KEYWORDS: filtration, drip irrigation, water quality. 


2021 ◽  
Vol 11 (9) ◽  
Author(s):  
M. Zielina

AbstractThe article presents research carried out on a sand/anthracite filter in a water treatment plant in Cracow in the south of Poland. These studies show that shutting down the filter after only three hours of operation, setting it aside for four hours and restarting without backwashing did not cause any visible deterioration in the quality of the produced filtrate. Stopping the same filter for four hours, however, after 68 h of operation, visible deterioration in the quality of the filtrate can be observed. After a significant initial deterioration, the quality of the filtrate slowly improved and after a few hours, it reached a level comparable to that before the filter was taken out of service. This was probably the result of characteristic changes in shear stress at the boundary of the deposit and flowing water in the capillaries, which accompanied changes of filtration rate. Decrease in the removal efficiency of coarser particles lasted longer and was greater than that of finer particles. Decrease in particle removal efficiency after restarting the dirty filter was difficult to identify by turbidity measurements, but clearly identifiable by measuring suspended solid concentration and the number of coarser particles. Interrupting the operation of a rapid filter shortly after it has been backwashed should not significantly reduce its efficiency, but after prolonged operation, it may adversely affect the quality of the filtrate.


2018 ◽  
Vol 1049 ◽  
pp. 012039
Author(s):  
N A Zuraini ◽  
N Alias ◽  
N Abd Rahman ◽  
S Harun ◽  
Z Ibrahim ◽  
...  

1993 ◽  
Vol 28 (11-12) ◽  
pp. 355-367 ◽  
Author(s):  
Y. P. Tsai ◽  
C. F. Ouyang ◽  
M. Y. Wu ◽  
W. L. Chiang

The effluent total BOD (or COD) concentration of the activated sludge process (A.S.P.) usually increases with suspended solid concentration. How to reduce effluent S.S. concentration, therefore, is the key issue of treatment efficiency for A.S.P. The varied return sludge and influent flow rate are two major operational factors of those affecting effluent S.S. concentration. However, the wastewater flow rate and substrate concentration in municipal wastewater treatment plant, due to the differences of city scale and life style, are significantly time-varied every day. Based on the above, the purpose of this study is to control in timely fashion return sludge flow rate with the variation of influent flow rate to minimize effluent S.S. concentration and meanwhile decrease the effluent total BOD (or COD) concentration. The fuzzy control theory is utilized in this study to forecast and control effluent S.S. concentration and further predict the MLSS concentration in aeration tank. It reveals that the inferred control strategies not only enable one to decrease effluent S.S.


REAKTOR ◽  
2017 ◽  
Vol 5 (1) ◽  
pp. 35
Author(s):  
Budiyono Budiyono

Pemodelan dan simulasi pada keadaan transien dilakukan terhadap sistem pengolahan air limbah dengan proses lumpur aktif tanpa resirkulasi lumpur. Model matematika pada keadaan transien disusun dengan membuat neraca massa substrat dan neraca massa sel. Persamaan yang diperoleh diselesaikan secara numerik. Beberapa parameter yang digunakan untuk penyusunan modelyaitu konsentrasi COD umpan 2.000 mg/l dan waktu tinggal cairan (Hydraulic Retention Time, HRT) bervariasi dari 8, 16, 24 hingga 32 hari. Konsentrasi mikroba (Mixed Liquor Suspended Solid, MLSS) awal divariasikan dari 250, 500, 1000 hingga 2000 mg/l. substrat terlarut awal di dalam bak aerasi divariasi dari 100, 300, 500 hingga 1000 mg/l. Parameter kinetika yang digunakan diperoleh dari literature yaitu laju pertumbuhan maksimum spesifik, laju kematian specific, koefisien perolehan sel dan konstanta setengah jenuh masing-masing 0,589 hari-1, 0,248 hari-1, 0,515 (mg sel/ mg substrat) dan 589 mg/l.Hasil simulasi menunjukkan bahwa waktu yang diperlukan untuk mencapai keadaan tunak tergantung pada HRT dan MLSS awal di dalam bak aerasi. Konsentrasi COD dan MLSS  di dalam bak aerasi pada keadaan transien  tergantung pada MLSS dan konsentrasi COD terlarut awal di dalam bak aerasi dan SRT. Dari hasil simulasi ini bias diambil rele of thumbs bahwa waktu yang diperlukan untuk mencapai keadaan tunak adalah sebesar 1-3 kali HRT pada HRT rendah satu kali HRT pada HRT tinngi.Kata kunci : simulasi dan pemodelan, proses lumpur aktif, keadaan transien


Desalination ◽  
2004 ◽  
Vol 167 ◽  
pp. 153-158 ◽  
Author(s):  
S. Katayon ◽  
M.J. Megat Mohd Noor ◽  
J. Ahmad ◽  
L.A. Abdul Ghani ◽  
H. Nagaoka ◽  
...  

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