Combined Orbal oxidation ditch with high performan

The Combined Orbal oxidation ditch with high performance for nitrogen removal (C-Orbal OD) is a patent product developed for wastewater treatment by Lingzhi Environmental Protection Co., Ltd. The C-Orbal OD applies biological technology. Therefore, there is no need to add any chemicals in treatment process. Yet, the nitrogen and phosphorous removal rate will be improved. This means that the direct operating costs of wastewater treatment will amount to only about USD0.045 per ton of wastewater. Lingzhi Environmental Protection Co., Ltd. has obtained patent certificates for this product from the Trademark Office in China and the United States. We Have also applied for PCT international patents in Brazil, Vietnam, India and South Africa. Compared to the common oxidation ditch, the C-Orbal OD has the following advantages: 50% less land occupation 20% - 50% less civil work costs 30%savings in direct operating costs Distinctivetotal nitrogen removal effect Orbal oxidation ditch + individually built secondary sedimentation tankOrbal oxidation ditch with high performance for nitrogen removal(secondary sedimentation tank being tangential to the outer channel)Combinatorial circular tank(secondary sedimentation tank in the centre)Land Occupation Length 118M94M146MWidth 106M70M68MEffective water depth 4.4M4.4M4.4MArea 12,499m26,579m29,919m2Concrete quantity 6,847.92 m36,046 m35,604 m3Civil work price 8,217,5007,255,2006,724,800Anaerobic tank YesYesNoNitrogen Removal YesYesNoPhosphor Removal YesYesNoCost of equipments HighMediumLow (*note )Costs of power HighMedium lowMedium low (*note )Advantages The oxidation ditch and the secondary sedimentation tank are built independently. Examination and repair of any of the structure does not affect operation of the other structures. Process is flexible This compact project layout has the smallest land occupation, which makes it easy for serial and parallel connection among the ditches. No connection lines or switch valves required. Construction cost is low, suitable for small-sized wastewater treatment plants (below 10,000 ton). No connection lines or switch valves are required. Shortages Many structures The whole set must be examined and repaired. The whole set must be examined and repaired. Note : As there is no internal backflow, only low power equipments are installed. If internal backflow is added, the equipment and pipe lines will not besuperior toa combinatorial tank. Comparing the above three design proposals under the condition of 4.4m effective water depth without considering nitrogen removal or phosphor removal, it can be concluded: 1. Proposal 1 requires the largest investment with high costsfor power, equipments and civil works. It also requires large area of land. Even removing nitrogen and phosphor, many projects often are not equipped with backflow systems and the removal of the toal nitrogen can not be assured. However, the removal rate of COD and BOD is stable. This traditional design process iscostly in all aspects. 2. Design proposal 2 covers the smallest land area - only 50% of that in proposal 1. With an effective water depth of 6m, even less land wilol be needed. 3. Investment size and land occupation for design proposal 3 is moderate. Operation costs arelow, but there is no internal backflow system. Furthermore, the width of the outer ditch, median ditch and the inner ditch do not coordinate with each other. Therefore, the effects of denitrification and dephosphorization can not be assured, neither can the removal of total nitrogen. The width of the outer ditch is over 10m, which is too wide for the placement of rotary disk aerators. Rotary disk aerators over 10mare not available in the market In terms ofnitrogen and phosphor removal, comparisons can bemade only between proposal 1 and 2. No internal backflow system can be added in proposal 3. Because of the process design, an internal backflow system can only be added in proposal 1.According to thecomparisons above, the combined Orbal oxidation ditch in proposal 2 can replace the traditional proposal 1, which will save 50% land occupation and 20% civil work input. Furthermore, operation costs will decrease significantly, whilethe total nitrogen removal is substantial. Combined Orbal oxidation ditches have been operating successfully at HeNan Fangcheng Wastewater Treatment Plant, Wuxi Chengbei Wastewater Treatment Plant, Sangpo Tannery Wastewater Treatment Plant, other municipal sewage treatment plantsand many domestic paper mill wastewater treatment plants.