Advantage of BIOX tank technology over aeration tank in secondary biological treatmen

D.D. Banerjee (7221596)

T.K. Bose (7221599)

English

Loughborough University Institutional Repository

M 28th WEDC Conference Kolkata (Calcutta), India, 2002 - SUSTAINABLE ENVIRONMENTAL SANITATION AND WATER SERVICESAdvantage of Biox Tank Technology over Aeration Tank in Secondary Biological Treatment D. D. Banerjee & T. K. Bose, I11oiaIntroduction The above case study was conducted at a Soft Drink Plant at Uttar Pradesh where Effluent Treatment Plant was stabilized using Biox Tank methodology. Biox Tank is a substitute for normal Activated Sludge Process where special type of plastic media is normally used to decrease the capacity of the Aeration Tank with increase in reduction of biological matter. The above plastic media is completely submerged inside the Aeration Tank with air being introduced by the help of Air Blower underneath the media bed. The above soft Drink Industry is in the process of making different types of syrups & mineral water of good quality with production rate of 600 bottles/ min. The raw effluent discharge from the factory, designed for 550 Cum/ day contains mainly sufficient suspended solids (TSS) with high BOD & COD load. The treatment plant was designed with the following raw influent characteristics. The influent characteristics were measured after 24 hours composite sampling and the outlet quality measured at the end of 20th day from the start up of the plant. Raw Inffluent Treated Effluent pH 9.2 7.42 BOD, mg/1 630 15.0 COD, mg/1 1456 156.0 TSS, mg/1 212.4 21.2 Oil & Grease, mg/1 22.5 1.3 Objective of the study The objective of the present study is to establish a commercially viable Effluent Treatment Plant by the Biox Tank methodology. Here, the infrastructure facility of local authority i.e., drainage system for the collection of industrial wastewater is not present except discharging it to the surrounding lands for gardening purposes. Thus, waste-water generated from the said.Soft Drink industry can not be discharged as such, in the surrounding land except proper treatment for maintaining ecology. The free-floating oil & grease has been separated primarily and thereafter wastewater is taken into the Biox Tank for the secondary treatment. After Biox Tank second stage aeration system is incorporated to take care of the additional biological load. The implementation of Biox Tank reduces the detention time to two-stage activated sludge process whereby decreases the capacity of the Aeration Tank. The initial cost including civil & mechanical cost as well as the operating cost for the Biox Tank technology is much less compared to double­stage aeration tank system. The Treatment Process The treatment process consists of a manually cleaned Bar Screen Chamber where initial removal of coarse solids is done followed by an Oil & Grease Trap, where the free floating oil & grease floats to the top and is skimmed off manually to a side pit. Water then overflows to two Equalisation Tanks placed in parallel for flow collection & homogenisation. As the effluent is highly alkaline in nature, acid (dilute HCl) is dosed in both the Equalisation Tanks. In the Equalisation Tanks air is introduced with the help of Air Blowers for proper mixing of chemicals. The biological process consists of two-stage aeration followed by settling. In Biox Tank, the organic matter is removed by micro-organisms attached tothe plastic PVC mdia underneath the water level in the Biox Tank. Air is provided in the Biox Tank for necessary oxygenation and mixing with the help of Air Blowers. Coarse bubble Diffusers are provided in the Biox Tank for proper aeration. The overflow effluent from Biox Tank gravitate to Aeration Tank, where further removal of BOD & COD is a�hieved. The same Air Blower is used for oxygenation & mixing inside the Aeration Tank. In the Aeration Tank fine bubble Diffuser membrane is provided for developing bacteria culture. From Aeration Tank effluent gravitates to the Settling Tank for removal of suspended solids. The underflow sludge from the Settling Tank is recycled back to the Biox Tank with part being discharged periodically to the Sludge Drying Beds. The overflow from the Settling Tank is collected in a Treated Water Holding Tank from where it is being used for gardening purposes. For proper flow measurement V­Notch Chamber is installed at the final discharge point. ,,, 

Advantage of BIOX tank technology over aeration tank in secondary biological treatment

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Advantage of BIOX tank technology over aeration tank in secondary biological treatment

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