Removal of Total Coliform and TSS for Hospital Wastewater by Optimizing the Role of Typha Angustifolia and Fine Sand-Gravel Media in Horizontal Sub Surface Flow Constructed Wetland

This study aims to evaluate the performance of a pilot-scale HSSF-CW utilizing Typha angustifolia and fine sand-gravel media in removing total coliform and TSS from hospital wastewater. Three pilot-scale HSSF-CW cells measuring 1.00 x 0.45 x 0.35 m3 were filled with gravel sand media with a diameter of 5 - 8 mm as high as 35 cm with a submerged media depth of 0.30 m. There were three treatments, namely the first cell (CW1) without plants, the second cell (CW2) was planted with a density of 12 Typha angustifolia plants, and the third cell (CW3) was planted with a density of 24 Typha angustifolia plants. The three HSSF-CW cells received the same wastewater load with total coliform and TSS contents of 91000 MPN / 100 mg and 53 mg / L, respectively, with Hydraulic Loading Rates 3,375 m3 per day. Wastewater was recirculated continuously to achieve the equivalent HSSF-CW area requirement. The experimental results show that the performance of CW3 is more efficient than CW1 and CW2 in total coliform and TSS removal for hospital wastewater. The pollutant removal efficiency at CW3 reached 91.76% for total coliform with one day hydraulic retention time and 81.00% for TSS with two days of hydraulic retention time. This study concludes that the HSSF-CW system using sand-gravel media with a diameter of 5 - 8 mm with a submerged media depth of 0.30 m and planted with Typha angustifolia with a tighter spacing proved to be more efficient in removing total coliform and TSS from hospital wastewater.

Download Full-text

Effect of Hydraulic Retention Time on Pollutant Removal Performance of Biological Contact Oxidation Process Treating Hospital Wastewater

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.507.725 ◽

2014 ◽

Vol 507 ◽

pp. 725-729

Author(s):

Bo Yu ◽

Ying Zhou ◽

Zheng Wen Huang ◽

Li Chen

Keyword(s):

Retention Time ◽

Hydraulic Retention Time ◽

Oxidation Process ◽

Removal Rate ◽

Pollutant Removal ◽

Hospital Wastewater ◽

Additional Processing ◽

Contact Oxidation ◽

Biological Contact Oxidation ◽

Processing Steps

A study on hospital wastewater treatment was carried out using biological contact oxidation process. The effect of hydraulic retention time (HRT) on BOD5, CODCr and SS removal was investigated. The results showed that the removal rate of BOD5, and CODCr was ascending with the increase of HRT using the contrast test of five different HRTs. When the HRT was more than 4h, the effluent BOD5, CODCr could meet the discharge standard (GB18466-2005). In considering of raising the biodegradability of effluent, 4h was recommended in this study. However, the whole trend of SS variation of system was not obvious with the increase of HRT, and the effluent SS could not meet the discharge standard (20mg/L). Thus, the additional processing steps to remove SS would be necessary.

Download Full-text

Role of hydraulic retention time and granular medium in microbial removal in tertiary treatment reed beds

Water Research ◽

10.1016/s0043-1354(03)00066-6 ◽

2003 ◽

Vol 37 (11) ◽

pp. 2645-2653 ◽

Cited By ~ 43

Author(s):

Joan Garcı́a ◽

Joan Vivar ◽

Maria Aromir ◽

Rafael Mujeriego

Keyword(s):

Retention Time ◽

Granular Medium ◽

Hydraulic Retention Time ◽

Tertiary Treatment ◽

Reed Beds ◽

Microbial Removal

Download Full-text

Effect of 200 days' sludge retention time on performance of a pilot scale submerged membrane bioreactor for high strength industrial wastewater treatment

Water Science & Technology ◽

10.2166/wst.2006.362 ◽

2006 ◽

Vol 53 (11) ◽

pp. 269-276 ◽

Cited By ~ 6

Author(s):

C.T. Hay ◽

D.D. Sun ◽

S.L. Khor ◽

J.O. Leckie

Keyword(s):

Retention Time ◽

Industrial Wastewater ◽

Membrane Bioreactor ◽

Hydraulic Retention Time ◽

High Strength ◽

Pilot Scale ◽

Submerged Membrane Bioreactor ◽

Sludge Retention Time ◽

Organic Removal ◽

Sludge Concentration

A high strength industrial wastewater was treated using a pilot scale submerged membrane bioreactor (MBR) at a sludge retention time (SRT) of 200 d. The MBR was operated at a high sludge concentration of 20 g/L and a low F/M ratio of 0.11 during 300 d of operation. It was found that the MBR could achieve COD and TOC overall removal efficiencies at more than 99 and 98% TN removal. The turbidity of the permeate was consistently in the range of 0.123 to 0.136 NTU and colour254 absorbance readings varied from 0.0912 to 0.0962 a.u. cm−1. The sludge concentration was inversely proportional to the hydraulic retention time (HRT), yielded excellent organic removal and extremely low sludge production (0.0016 kgVSS/day).

Download Full-text

Experimental reedbed systems for the treatment of airport runoff

Water Science & Technology ◽

10.2166/wst.1997.0697 ◽

1997 ◽

Vol 36 (8-9) ◽

pp. 385-390 ◽

Cited By ~ 14

Author(s):

D. M. Revitt ◽

R. B. E. Shutes ◽

N. R. Llewellyn ◽

P. Worrall

Keyword(s):

Pilot Scale ◽

Surface Flow ◽

Pollutant Removal ◽

Biological Processes ◽

Metal Concentrations ◽

Physical Chemical ◽

Flow Systems ◽

Total Ammonia ◽

Removal Efficiencies

The relative efficiencies of pollutant removal from airport runoff by three different designs of pilot scale reedbed treatment systems located at Heathrow airport are described. The sub-surface flow and surface flow systems generally performed more effectively than the rafted systems for reduction of BOD, COD, total ammonia, nitrate, phosphate and metal concentrations. The variable removal efficiencies are explained in terms of the physical, chemical and biological processes which are relevant to each reedbed system.

Download Full-text

Optimising the Hydraulic Retention Time in a Pilot-Scale Microbial Electrolysis Cell to Achieve High Volumetric Treatment Rates Using Concentrated Domestic Wastewater

Molecules ◽

10.3390/molecules25122945 ◽

2020 ◽

Vol 25 (12) ◽

pp. 2945 ◽

Cited By ~ 3

Author(s):

Daniel D. Leicester ◽

Jaime M. Amezaga ◽

Andrew Moore ◽

Elizabeth S. Heidrich

Keyword(s):

Retention Time ◽

Hydraulic Retention Time ◽

Oxygen Demand ◽

Domestic Wastewater ◽

Direct Analysis ◽

Pilot Scale ◽

Electrolysis Cell ◽

Treatment Technique ◽

Microbial Electrolysis Cell ◽

Microbial Electrolysis

Bioelectrochemical systems (BES) have the potential to deliver energy-neutral wastewater treatment. Pilot-scale tests have proven that they can operate at low temperatures with real wastewaters. However, volumetric treatment rates (VTRs) have been low, reducing the ability for this technology to compete with activated sludge (AS). This paper describes a pilot-scale microbial electrolysis cell (MEC) operated in continuous flow for 6 months. The reactor was fed return sludge liquor, the concentrated filtrate of anaerobic digestion sludge that has a high chemical oxygen demand (COD). The use of a wastewater with increased soluble organics, along with optimisation of the hydraulic retention time (HRT), resulted in the highest VTR achieved by a pilot-scale MEC treating real wastewater. Peak HRT was 0.5-days, resulting in an average VTR of 3.82 kgCOD/m3∙day and a 55% COD removal efficiency. Finally, using the data obtained, a direct analysis of the potential savings from the reduced loading on AS was then made. Theoretical calculation of the required tank size, with the estimated costs and savings, indicates that the use of an MEC as a return sludge liquor pre-treatment technique could result in an industrially viable system.

Download Full-text