To Examine Efficiency of Sequential Batch Reactor to Treat Domestic Wastewater

Abstract

The Study aims to examine operation effectiveness of Sequential Batch Reactor (SBR) of wastewater treatment plant in India. Sewage wastewater consists umpteen of chemical pollutants, which can be measured by chemical parameters such as Chemical Oxygen Demand (COD) and Total suspended Solid that, lead to Environmental pollution, if discharge without proper treatment. The correlation between COD and TSS-VSS removal was explored using the six on-plant SBRs, receiving medium strength domestic sewage. Samples were collected from Inlet channel and outlet channel of the Sequential Batch Reactor (SBR). Composite samples were collected for period of 15 Days and experiment of Chemical Oxygen Demand (COD) and Total Suspended Solid and Volatile Suspended Solid (TSS-VSS) were performed by Standard Methods mentioned in APHA. Result of experiments performed express that, average COD and TSS in Inlet wastewater (Influent) are 260 mg/L and 180 mg/L respectively and average COD and TSS of Effluent are 29.4mg/L and 6.2 mg/L respectively. Reduction in COD and TSS is 85-87 % and 85-90% respectively. This preliminary study shows that SBR are potential, a feasible for treatment of domestic wastewater.

Introduction

I. INTRODUCTION

Complex Environmental Problems are created by combine effect of industrialization, urbanisation, climate change, Green House effect and so on. These challenges are getting worse, with rising population especially in the countries such as India. Waste water treatment characterises major solution and reduces number of pollutants disposed in water body.

Characteristics of sewage is differed from place to place and time to time. Sewage consisted in various kind of pollutants, that can be classified as organic or inorganic pollutants.

An EPA report 1983, encapsulate by stating that “the SBR is no more than an activated sludge system which operates in time rather than in space” (ETB, 1999) . Major difference in these technologies is that SBR carry out equalization, biological treatment, and secondary clarification in a single tank using time base sequence. In the process including sedimentary remove (Suspended solids), Biodegradation, biosolid separation are archive in the same reactor but with different time period.

The main process of Sequential Batch Reactor divided into three parts; Fill & aeration, Settling and Decanting. During the fill & aeration period, gate of Inlet channel open for fixed time and water enter in the selector zone of SBR tank. Aeration through diffuser with help of blower from bottom of reaction tank. During the fixed fill & aeration time, oxygen is bubbled through the wastewater to reduces biochemical and chemical oxygen demand. The floc foaming microorganism uses pollutants as nutrition and remove it from the waste water and that creates activated sludge.

During the settling time bubbling of air and filling of wastewater is stopped and activated sludge is allowed to settles in the quiescent condition. In the normal condition, sludge settle down and get separate from the clear water.

In the end of Settling time the decanter weir moves in lower direction and touch water surface. Then Decanting start, the clear supernatant from SBR tank is removed with the help of decanter. After Decanting the weir return to it’s initial (Parked) Position. By this way the whole batch of treated influent gets treated in just one tank.

Time of each Cycle: (180 minutes)

Fill and aeration - 0 minutes

Settling                - 30 minutes

Decanting           - 60 minutes

II. COLLECTION OF SAMPLES

Wastewater samples were collected on daily basis from inlet and outlet of the STP in white plastic containers that were prior cleaned with metal-free soap, rinsed repeatedly with distilled water, then soaked in 10% nitric acid for 24 h and finally rinsed with ultrapure water. All water samples were stored in insulated cooler containing ice and taken on the same day to laboratory and stored at 4 °C until processing and analysis (APHA 2005). pH was determined by pH meter, Chemical oxygen demand (COD) was determined using reflux method and Total Suspended solids and volatile suspended solids were determined by gravimetric method.

For the research purpose composite sample of effluent and effluent were collected for space of 15 days. 100 mL sample were collected in each cycle; thus 800 mL sample was collected for 8 cycle per day.

III. METHOD OF DETERMINATION

 The inoculum of the three reactors studied was secondary aerobic sludge from the wastewater treatment plant (WWTP) of Surat (India). The reactors were fed with the raw domestic wastewater from the city of Surat (India). The analysis of the main parameters of the influent feeding water the chemical oxygen demand and total-volatile suspended solids of plant are given in table 1 and effluent concentration in table 2, Which were determined according to standard methods suggested by the Standard Methods for the Examination of Water and Wastewater manual (2005). ph was determined by pH meter, Chemical oxygen demand (COD) was determined using reflux method and Total Suspended solids and volatile suspended solids were determined by gravimetric method of volatilization.

(Table-1 – Influent parameters studied from date12december 2022 to 26 December 2022)

(Table-2– Effluent parameters studied from date12december 2022 to 26 December 2022)

Conclusion

Study revealed that SBR-based treatment plant significantly removed the disagreeable physiochemical properties of wastewater before its discharge into water body. Optimum concentration could be removed if all operational conditions were well maintained.

References

[1] Wastewater Technology Fact Sheet Sequencing Batch Reactors, EBT, Washington DC https://www3.epa.gov/npdes/pubs/sbr_new.pdf [2] (P1) https://kyocp.wordpress.com/2016/04/08/sequencing-batch-reactor-process-gaining-popularity [3] APHA, AWWA & WEF 2005 Standard Methods for the Examination of Water and Wastewater, 21st edition American Public Health Association/American Water Works Association/Water Environment Federation, Washington, DC, USA

Copyright

Copyright © 2023 Siddhi Ramsnehi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.