A novel and cost-effective sewage treatment system consisting of UASB pre-treatment and aerobic post-treatment units for developing countries

1997 ◽  
Vol 36 (12) ◽  
pp. 189-197 ◽  
Author(s):  
Izarul Machdar ◽  
Hideki Harada ◽  
Akiyoshi Ohashi ◽  
Yuji Sekiguchi ◽  
Hiroyuki Okui ◽  
...  
Keyword(s):  
Developing Countries ◽  
Low Cost ◽  
Sewage Treatment ◽  
Cost Effective ◽  
Post Treatment ◽  
Cod Removal ◽  
Treatment System ◽  
Treatment Unit ◽  
Pre Treatment ◽  
Sewage Treatment System

A novel sewage treatment system was proposed, which consists of a UASB anaerobic pre-treatment unit and the following DHS (downflow hanging sponge-cubes) aerobic post-treatment unit, as a low-cost and easy-maintenance process for developing countries. Over six months experiment by feeding sewage our proposed system achieved 94% of total-COD removal, 81% of soluble-COD removal, and nearly perfect SS removal and total-BOD removal at the overall HRT of 8.3 hr (7 hr in UASB and 1.3 hr in DHS unit). Moreover, the DHS reactor was capable of performing high (73–78%) nitrification. Our whole system requires neither external aeration input nor withdrawal of excess sludge.

Combination of a UASB reactor and a curtain type DHS (downflow hanging sponge) reactor as a cost-effective sewage treatment system for developing countries

2000 ◽  
Vol 42 (3-4) ◽  
pp. 83-88 ◽  
Author(s):  
I. Machdar ◽  
Y. Sekiguchi ◽  
H. Sumino ◽  
A. Ohashi ◽  
H. Harada
Keyword(s):  
Sewage Treatment ◽  
Cost Effective ◽  
Ammonia Nitrogen ◽  
Treatment System ◽  
Uasb Reactor ◽  
Municipal Sewage ◽  
Combined System ◽  
Treatment Unit ◽  
Pre Treatment ◽  
Sewage Treatment System

The second generation of our originally proposed sewage treatment system, which consists of a UASB reactor as an anaerobic pre-treatment unit and curtain-type DHS (downflow hanging sponge) reactor as an aerobic post-treatment unit, was installed at a municipal sewage treatment site. A 550-day continuous experiment demonstrated that the whole combined system successfully achieved 94–97% of unfiltered-BOD removal, 81–84% of unfiltered-COD removal, and 63–79% of SS removal, at an overall HRT of 8 h (6 h for UASB and 2 h for DHS units). The combined system performed an excellent organic removal as well as a fairly efficient nitrification, i.e. 52–61% of ammonia-nitrogen removal. Our proposed combined system possesses prominent advantages: requiring neither external aeration input nor excess sludge withdrawal.

Assessment of COD Removal Characteristics of Night Soil Wastewater by Using a Shipboard Sewage Treatment System

2021 ◽  
Vol 22 (1) ◽  
pp. 1-7
Author(s):  
Hyeon-Jo Ji ◽  
Byung-Gil Jung ◽  
Jin-Hee Jeong ◽  
Dae-Yeol Shin ◽  
Young-Ik Choi
Keyword(s):  
Sewage Treatment ◽  
Cod Removal ◽  
Treatment System ◽  
Sewage Treatment System

Removal of indigenous coliphages and fecal coliforms by a novel sewage treatment system consisting of UASB and DHS units

2002 ◽  
Vol 46 (11-12) ◽  
pp. 303-309 ◽  
Author(s):  
S. Uemura ◽  
K. Takahashi ◽  
A. Takaishi ◽  
I. Machdar ◽  
A. Ohashi ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Sewage Treatment ◽  
Treatment System ◽  
Fecal Coliforms ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Combined System ◽  
Treatment Unit ◽  
Indicator Microorganisms ◽  
Sewage Treatment System

A novel sewage treatment system, which consists of an upflow anaerobic sludge blanket (UASB) pre-treatment unit and the following downflow hanging sponge (DHS) unit for polishing up the UASB effluent, was developed as a cost-effective and easy-maintenance sewage treatment system for developing countries. A long-term experiment with actual sewage was conducted in order to evaluate its treatment efficiency of organic substances, nutrients, and pathogen indicator microorganisms such as total coliphages, F+-specific RNA coliphages (RNA coliphages), and fecal coliforms. The main objective of this paper is to investigate the removal efficiency of those indicator microorganisms by the UASB-DHS combined system. The results obtained from the continuous flow experiment indicated a fairly promising removal of the indicator microorganisms, i.e., the log10 reductions of total coliphages, RNA coliphages, and fecal coliforms (based on sewage and DHS effluent) achieved were 2.01 log, 2.02 log, and 2.57 log, respectively. The UASB-DHS combined system was superior to the conventional activated sludge process in the reduction of fecal coliforms, but in the reductions of total and RNA coliphages, the system showed somewhat less removal efficiency. The vertical reducing patterns of the indicator microorganisms along the DHS reactor were also discussed.

Upgrading Wastewater Treatment by Water Hyacinth in Developing Countries

1990 ◽  
Vol 22 (7-8) ◽  
pp. 153-160 ◽  
Author(s):  
Pradeep Kumar ◽  
R. J. Garde
Keyword(s):  
Wastewater Treatment ◽  
Water Hyacinth ◽  
Treatment Plant ◽  
Cod Removal ◽  
Treatment System ◽  
Synthetic Wastewater ◽  
Second Phase ◽  
Treatment Unit ◽  
Batch Studies ◽  
New Treatment

With increasing stress on existing wastewater treatment systems, it is necessary either to upgrade the treatment unit(s) or install an entirely new treatment plant. Obviously, the upgrading is preferred over the alternative of having a new system. Keeping this in view, in the present project, an attempt has been made to explore the possibility of upgrading existing facultative ponds using water hyacinth. Bench-scale batch studies were designed to compare the performance of hyacinth treatment system with facultative ponds. Investigations were carried out with synthetic wastewater having COD in the range of 32.5-1090 mg/l. The efficiency of COD removal in water hyacinth ponds was 15-20 percent more than the facultative ponds. Based on the results, an empirical model has been proposed for COD removal kinetics. In the second phase of the project a hyacinth pond was continuously operated. BOD, COD, TS, TN, TP, pH, and DO were regularly monitored. However, the DO of the effluent from hyacinth treatment system was considerably reduced. Effluent should be aerated before it is discharged. The results indicate that the existing facultative ponds can be stalked with water hyacinth to improve their performance as well as hyacinth treatment systems can be installed to support the conventional treatment.

A New Sewage Treatment System with Fluidized Pellet Bed Separator

1993 ◽  
Vol 27 (11) ◽  
pp. 185-192 ◽  
Author(s):  
Tatsuhiko Suzuki ◽  
Norihito Tambo ◽  
Genzo Ozawa
Keyword(s):  
Molecular Weight ◽  
Biological Treatment ◽  
Membrane Filter ◽  
Sewage Treatment ◽  
Treatment System ◽  
Organic Substances ◽  
Treatment Rate ◽  
Treated Water ◽  
Biological Filter ◽  
Sewage Treatment System

A new sewage treatment system which is composed of a fluidized pellet bed separator, aerobic biological filter and micro–membrane filter was studied. In the newly proposed system, at the first stage, higher molecular weight organic substances and suspended matter are removed by way of chemical coagulation and flocculation. For the operation, a new fluidized pellet bed separator with high separation rate of 200-300 m/day is introduced to improve the treatment rate. A large percentage of organ ic substances are removed by the new coagulation/flocculation process. Hence, the total BOD load to be applied to the following biological treatment becomes very low. In addition to this, the organic substances in the effluent from the fluidized pellet bed separator are on lylower molecular weight substances which are easily biologically decomposed. Therefore easily decomposing and lower concentration pollutants enable use of a simple biological treatment p rocess such as aerobic biological filter with as short a detention time as 1 hour. Finally, effluent from the biological filter is treated by a micro-membrane filter. By the membrane process, suspended matte rs in the biologically treated water can be removed completely. Phosphate concentration of the treated water is very low, which is caused by aluminum coagulation in the first step and biological intake of the nutrient in the second step followed by complete sol id liquid separation in the third step.

scholarly journals The Contribution of Cognitive Impulsivity to Criminal Risk

2021 ◽  
Author(s):  
◽  
Rebecca K. Bell
Keyword(s):  
Impulse Control ◽  
Post Treatment ◽  
Trait Anger ◽  
Special Treatment ◽  
Treatment Programme ◽  
Treatment Change ◽  
Anger Control ◽  
Treatment Unit ◽  
Cognitive Behavioural ◽  
Pre Treatment

<p>Impulsivity increases risk for general, violent and sexual offending. Accordingly, helping offenders to become better regulators of their impulses is one goal of offender rehabilitation. In a correctional setting, the assessment of impulsivity focuses on personality and behaviour, but not cognition; cognitive impulse control impairments are inferred from personality styles and behavioural patterns suggestive of acting before thinking. However, empirical findings challenge the validity of inferring cognition from personality and behavioural measures. Additionally, without assessing cognition, practitioners are limited in their ability to isolate which cognitive processes are most impaired and therefore worthy of intervention for individual offenders.  To establish the contribution of cognitive impulse control to criminal risk, a theoretically derived, empirically supported neurocognitive assessment framework was adopted. The framework is based on the notion that impulsive behaviour arises from three, potentially dissociable skill domains that support impulse control: decisionmaking, perceptual and motor impulse control. A cohort of 77 men attending intensive cognitive-behavioural rehabilitation was recruited from four of New Zealand’s prison-based Special Treatment Unit Rehabilitation Programmes (STURPs). A neurocognitive battery of five tasks collectively representing each cognitive impulse control domain was administered before and after the 8-month treatment programme.  Study One explored pre-treatment clinically impaired performance within and across each cognitive impulse control domain. Compared to normative data, performance was typically in the average to below average range, but it was not clinically impaired overall. When performance was clinically impaired, it was most pronounced on tasks requiring cognitive flexibility.  Study Two explored treatment change in cognitive impulse control. The study also compared pre-treatment cognitive impulse control between offenders who went on to complete the treatment programme and those who were prematurely removed for responsivity or conduct-related issues. No pre-treatment cognitive impulse control differences were found between treatment completers and non-completers. Treatment completers displayed small pre-post treatment improvements in some areas of cognitive impulse control, but not others.  Study Three explored cross-sectional and predictive relationships between cognitive impulse control, dynamic criminal risk, trait anger and anger control. Although there was little association between these variables before treatment, some cognitive impulse control outcomes predicted post-treatment dynamic criminal risk, trait anger and anger control. Thus, the evidence suggested that certain aspects of cognitive impulse control might function as facilitators of treatment change.  Together, the findings highlighted the importance of evaluating cognitive impulse control as part of the risk assessment, and clinical formulation process. The findings also suggested that interventions designed to develop cognitive impulse control abilities either before, or as a complement to traditional cognitive-behavioural interventions, have the potential to maximise treatment response.</p>

Comparison of PPCPs removal on a parallel-operated MBR and AS system and evaluation of effluent post-treatment on vertical flow reed beds

2011 ◽  
Vol 63 (10) ◽  
pp. 2411-2417 ◽  
Author(s):  
R. Reif ◽  
A. Besancon ◽  
K. Le Corre ◽  
B. Jefferson ◽  
J. M. Lema ◽  
...  
Keyword(s):  
Retention Time ◽  
Low Cost ◽  
Sewage Treatment ◽  
Personal Care Products ◽  
Post Treatment ◽  
Treatment Quality ◽  
Municipal Sewage ◽  
Vertical Flow ◽  
Personal Care ◽  
Reed Beds

The presence in the aquatic environment of xenobiotics such as Pharmaceutical and Personal Care Products (PPCPs) has emerged as an issue of concern. Upgrading sewage treatment quality with modern technologies such as Membrane Bioreactors (MBRs) and/or implementing a further post-treatment might mitigate the release of xenobiotics into surface waters. The performance of two processes treating municipal sewage, a MBR and an Activated Sludge (AS) unit, have been compared in terms of PPCPs removal. Moreover, their effluents were treated using vertical flow reed beds. Both systems were operated under similar conditions, more specifically Hydraulic Retention Time (HRT), maintained at 8 hours, and Sludge Retention Time (SRT) set at 6 and 20 days. Pharmaceuticals belong to therapeutic groups such as antiepileptics (carbamazepine) and analgesics (ibuprofen, naproxen, diclofenac), whereas the personal care products are musk fragrances (galaxolide and tonalide). Xenobiotics removals achieved in the MBR showed better results, particularly for the acidic drugs ibuprofen (87% vs. 50%) and naproxen (56% vs. 6%) operating at low SRT. After filtration through vertical flow reed-beds, PPCPs content in effluents was decreased, below 1 ppb in most cases, improving the effluent quality and confirming reed-beds as an interesting low cost alternative in order to attenuate xenobiotics contamination.

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