Water Recycle Group

OXIDATION DITCH INDUSTRIAL WASTEWATER TREATMENT

Medium to large industrial sites can have cost-effective chemical-free or chemical-minimized wastewater treatment using oxidation ditch sewage systems. These operate as stand-alone biological treatment units and are in operation across the Asia-Pacific region.

WRG evaluated numerous variants developed to recommend and supply Oxidation Ditch (or single stage nitrification) wastewater and sewage treatment systems in association with technology partners Environmental Holdings and AWA-Envirotech. The processes involved in oxidation ditches have dramatic benefits over larger footprint systems on an area and volume treated basis.

Fujian Mawei Industrial Estate 10 ML/D Oxidation Ditch WWTP

As indicated below, oxidation ditch systems are installed worldwide, with significant reduction in land space requirements, often allowing expansion of industrial activities. The systems are now increasingly being used for food processing, pulp, textiles and chemical plants. Oxidation Ditch systems are also very effective in Urban Sewage Treatment Applications

Traditional industrial wastewater systems are static, large footprint and energy intensive. WRG's preferred wastewater and sewage treatment is smaller scale, biologically aerobic, low energy input, minimal odour, mostly chemical-free with fast reaction times suitable for reuse applications.

PT Kertas Kraft Pulp Mill, Indonesia - Oxidation Ditch 38.5ML/D

Process Overview

The Oxidation Ditch is a highly efficient aeration system using very low speed surface aerators. Aerators are mounted at watercourse channels in a racetrack configuration to provide complex mixing in the aeration zones. Plug flow exists in the channels between the aerators.

Flow velocity of 0.3m/second is maintained in the channels due to the pumping action of the aerators. Surface aerators applied in the conventional systems are generally designed to have a power intensity of 0.7 to 1.2 HP per 1,000 cubic ft, compared to an Oxidation Ditch which are typically designed at 0.4 HP per 1,000 cubic ft. This results in both better aeration for BOD reduction, etc, as well as very large power cost savings over conventional sewage systems. Flexibility can be achieved by adjustable immersion of aerators, alternating operation of aerators, or a variable rpm of the aerator. Equipment life of the aerator could easily exceed 30 years.

Low speed surface aerators have the following power ratings 5.5kW, 7.5kW, 11kW, 15kW, 18.5kW, 22kW, 30kW, 37kW, 45kW, 55kW, 75kW, 90kW, 110kW, 132kW and 160kW. Australian designed impellers are supplied ranging from 1.3m to 4.0m in diameter.

Achievable Results

Oxidation Ditch Industrial Wastewater Treatment benefits include:
95-99% BOD removal efficiency
Over 90% Nitrogen removal by denitrification
Over 50% elimination of Phosphorius compounds
Over 95% Phosphorius removal if Fe salts added
Lowest excess and stable sludge production
Effective and safe ammonia removal
Low to minimal odour emissions
Able to handle major hydraulic and biological shock loadings
Maximum operational simplicity
Limited sludge processing and treatment required
Minimal operational control required
Minimization of construction cost
Potential integration with tertiary wastewater treatment

Site Applications

Site applications suited for Oxidation Ditch Industrial Wastewater Treatment include:

    Pulp and Paper mills
    Textile Dyeing plants
    Tanneries
    Petrochemcial plants
    Edible Oil refineries
    Milk Powder production
    Coconut Milk Powder manufacturing
    Sugar Mills
    Soft Drink Factories
    Breweries
    Piggeries
    Duck Farms
    Dairies
    Poultry Farms
    Abbatoirs
    Food Processing
    Urban Sewage Applications

Key Specifications

System SRT Loading %BOD Removal Aerator Detention Hours Nitrifi-cation Recirculated Underflow Solids Rate
Extended Aeration >30 90%+ 16-24 Yes 100-300
Conventional 4-8 90-95% 4-8 Possible 30-100
High Rate 2-4 85-90% 2-4 No 30-100
Modified Aeration <1 60-75% 0.5-2 No 10-30
Contact Stabilization 3-10 85-95% - Possible 25-75
Contact - 85-95% 1.0-3.0 No 50-100
Stabilization - - 3.0-6.0 Possible -
Oxidation Ditch 10-15 95%+ 6-12 Yes 30-100

Reference Sites

There are numerous Oxidation Ditch sewage treatment units operating 24 hours/day in the Asia Pacific region, including:

Flow kL/D Client Location Application
50,000 Linqing Pulp & Paper Shandong China Pulp Mill
38,500 PT Kertas Kraft Aceh Indonesia Pulp Mill
35,000 Binzhou Wanghe Paper Shandong China Pulp Mill
30,000 Yebin Pulp & Paper Sichuan China Pulp Mill
25,000 Louhe Pulp & Paper Henan China Pulp Mill
10,000 PT Kahatex Bandung Indonesia Textile Dyeing
10,000 Fujian Mawei Industrial Estate Fujian China Industrial Zone
5,000 PT Adetex Bandung Indonesia Textile Dyeing
700 Tan Brothers Singapore Piggery
600 PT Inolakto Indonesia Dairy
500 PT PIX Medan Indonesia Sugar Mill
300 Matsushita Refrigeration Melaka Malaysia Electronics Plant
300 PT Indonesia Korea Tannery Indonesia Tannery
300 PT Multi Bintang Medan Indonesia Coca Cola Plant
100 S & P Coconut Batu Pahat Malaysia Coconut Milk Plant

Technical Information Downloads

Technical and issue documentation PDF files can be downloaded from this page by clicking on the relevant hyperlink.

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