- Secondary treatment: Attached growth and combined processes

Author(s):  
Jérôme Guegan ◽  
Claire Brechet ◽  
Julien Nelson

Abstract. Computers have long been seen as possible tools to foster creativity in children. In this respect, virtual environments present an interesting potential to support idea generation but also to steer it in relevant directions. A total of 96 school-aged children completed a standard divergent thinking task while being exposed to one of three virtual environments: a replica of the headmistress’s office, a replica of their schoolyard, and a dreamlike environment. Results showed that participants produced more original ideas in the dreamlike and playful environments than in the headmistress’s office environment. Additionally, the contents of the environment influenced the selective exploration of idea categories. We discuss these results in terms of two combined processes: explicit references to sources of inspiration in the environment, and the implicit priming of specific idea categories.


2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Nusa Idaman Said ◽  
Ikbal Ikbal ◽  
Satmoko Yudo

Sejalan dengan pertumbuhan penduduk yang sangat pesat dan meningkatnya pencemaran air tanah maupun air permukaan, serta distribusi sumber air untuk konsumsi pemakaian air yang tidak merata telah menyebabkan ketidak-seimbangan antara  pasokan dan kebutuhan akan air. Oleh karena itu, menjadi perhatian yang penting dalam melakukan upaya-upaya dalam hal penyediaan sumber air. Salah satu alternatif yang banyak mendapat perhatian di banyak negara di dunia adalah menggunakan teknologi daur ulang air limbah sebagai sumber air baku untuk penyediaan air bersih. Industri migas merupakan salah satu industri yang mempunyai kebutuhan akan air bersih yang besar, khususnya kilang minyak. Pemakaian air di kilang minyak tersebut cukup besar yaitu sebesar 1.400 m3 perjam, apabila air hasil buangannya dapat di daur ulang sebesar 10% atau lebih saja maka kebutuhan air bersih akan dapat dihemat. Tujuan dari kegiatan ini adalah melakukan desain instalasi daur ulang air di suatu kilang minyak. Konsep yang umum dari daur ulang adalah melakukan pengolahan air limbah untuk dijadikan air bersih, dengan menggunakan kombinasi proses pra-pengolahan (preliminary treatment), pengolahan primer (primary treatment), pengolahan primer lanjutan (advanced primary treatment), pengolahan sekunder (secondary treatment), dan pengolahan tersier (tertiary/advanced treatment). Dengan kombinasi proses tersebut dapat mengolah air limbah sampai menghasilkan air olahan dengan kualitas sebagai air minum.  Hasil dari kegiatan ini adalah diperolehnya desain pilot plant instalasi daur ulang air limbah di industri migas dengan kapasitas  9 m3/jam. Kata kunci: pencemaran air, air limbah, desain daur ulang air, kilang minyak


2014 ◽  
Vol 13 (1) ◽  
pp. 145-152 ◽  
Author(s):  
Alireza Valipour ◽  
Seyed Masoud Taghvaei ◽  
Venkatraman Kalyan Raman ◽  
Gagik Badalians Gholikandi ◽  
Shervin Jamshidi ◽  
...  

1988 ◽  
Vol 23 (4) ◽  
pp. 568-577
Author(s):  
Harold S. Bailey

Abstract The water quality of the upper 110 kilometres of the St. Croix River is considered to be pristine. A major industrial discharge renders the lower 14 kilometres of the river a water quality limited segment. Prior to 1970 the Georgia-Pacific Pulp and Paper Mill at Woodland, Maine, discharged untreated effluent directly into the river causing dissolved oxygen concentrations to drop well below 5 mg/L, the objective chosen in the interest of restoring endemic fish populations. Since 1972, the Mill has installed primary and secondary treatment, regulated river discharge rate and effluent composition which has greatly improved the summer dissolved oxygen regime. By 1980, dissolved oxygen concentrations were generally above 5.0 mg/L and restocking the river with Atlantic Salmon (Salmo salar) was initiated.


1982 ◽  
Vol 14 (6-7) ◽  
pp. 429-442
Author(s):  
I L Bogert

A one-year experimental program conducted at Edgewater, New Jersey, U.S.A. evaluated the concept of providing secondary treatment by the installation of rotating biological contactors (RBC's) in modified primary sedimentation tanks. A primary tank was divided horizontally into two zones separated by an intermediate floor. Four RBC's were placed in the upper zone. The lower zone provided secondary sedimentation. High rate primary sedimentation was provided to remove grit and trash without removing substantial portions of BOD and SS. The experimental program funded by the U.S. EPA and the Borough of Edgewater was conducted over a full year at different loads. The system proved to be an effective secondary treatment process with little difference in treatment efficiency between summer and winter conditions.


1994 ◽  
Vol 29 (12) ◽  
pp. 31-40 ◽  
Author(s):  
Pia Prohaska Brinch ◽  
Kim Rindel ◽  
Kathryn Kalb

Due to the introduction of stricter nutrient effluent standards, many existing wastewater treatment plants performing only primary or secondary treatment are about to be upgraded. As the space available at the plants is, however, often limited, processes are required which will accommodate the need for increased treatment capacity without requiring much more space. In the hydrolysis of primary or pre-precipitated sludge direct-degradable organic carbon is produced which can speed up the reaction rate and increase both biological phosphorus and nitrogen removal. Full-scale tests with dosing of hydrolysate for biological P and N removal, respectively, have shown that this is a most viable process. The use of on-line monitoring has improved the process further.


1997 ◽  
Vol 36 (1) ◽  
pp. 129-137 ◽  
Author(s):  
Vibeke R. Borregaard

In the upgrade of wastewater treatment plants to include biological nutrient removal the space available is often a limiting facor. It may be difficult to use conventional suspended growth processes (i.e. activated sludge) owing to the relatively large surface area required for these processes. Recent years have therefore seen a revived interest in treatment technologies using various types of attached growth processes. The “new” attached growth processes, like the Biostyr process, utilise various kinds of manufactured media, e.g. polystyrene granules, which offer a high specific surface area, and are therefore very compact. The Biostyr plants allow a combination of nitrification-denitrification and filtration in one and the same unit. The results obtained are 8 mg total N/l and an SS content normally below 10 mg/l. The plants in Denmark which have been extended with a Biostyr unit have various levels of PLC control and on-line instrumentation.


2018 ◽  
Vol 2018 (16) ◽  
pp. 1071-1083
Author(s):  
Francois Jolibois ◽  
Kar Munirathinam ◽  
Lauren Lundquist ◽  
David Marrs ◽  
Perry Lankford

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