Alumnus applies an advanced combined model for wastewater treatment

His new model, which was successfully applied, has been adopted by the company he works for. The Surat Municipal Corporation is now updating one of its wastewater treatment plants. If the plant, which will come into operation by May, proves efficient, the model will be used to update old plants and build new ones in Surat and other Indian cities.

Mayank Mithaiwala, an experienced engineer with increasing responsibilities at work, has always had an eager intellectual curiosity. That pleasure of learning pushed him to join the UNESCO-IHE Master’s programme in Municipal Water and Infrastructure in 2003. He received a temporary leave from his position as a Drainage Engineer at the Surat Municipal Corporation in India and travelled to Delft, fully committed to getting the utmost out of this experience. In February 2005 he completed his MSc studies with Distinction.

He proposed a rather challenging topic for his research, as he undertook a novel attempt to combine two models: one for wastewater treatment by activated sludge (called ASM) and the other for sludge treatment (ADM), and to apply the new model to a treatment plant in his city of Surat.

In his work, Mayank combined various process engineering skills that are increasingly becoming a trademark of a modern sanitary engineer. He performed plant assessment and evaluation, designed and executed an on-site sampling programme, learned how to master and apply complex mathematical models, and how to transfer the results into practical applications.

It soon appeared that Mayank’s work was far more than an ‘attempt’, as he was able to successfully apply the coupled model on a plant treating wastewater from about 500,000 people in the city of Surat. Surat, a heavily populated city that thrives with more than 3.2 million inhabitants, has several water treatment plants, the Anjana Wastewater Treatment Plant being one of the major ones, with 12 biological tanks of approximately 80,000 m3/d capacity. This was the perfect location to test Mithaiwala’s coupled model.

His study showed that the coupled model was very capable of predicting current plant operations. Mithaiwala’s work is the first successful application of such a combined model on a full-scale plant, and the first modelling demonstration involving a plant in a developing country operating under tropical conditions.

After his studies at UNESCO-IHE, Mayank returned to Surat. His daily work at the Municipal Corporation, where he worked since 1996, provided him with the enabling environment to continue and further develop the work carried out at UNESCO-IHE. He was assigned the task of leading the study on the extension of the Anjana plant, paying special attention to the new regulations for nitrogen removal. India has recently tightened its water pollution and environmental regulations, bringing them in line with international standards. The new legislation aims at reducing the authorised levels of biochemical oxygen demands (which measures the bacteria in the water) and suspended solids disposal. As regulations become stricter, industries and water facilities will be undertaking upgrading processes.

Once the upgrade is fully in place, the plant is expected to meet the desired and quite strict standards concerning nitrogen content in the effluent, as well as to provide better pollution prevention of Koyli Creek, a river that ultimately discharges into the nearby Arabian Sea. The upgrading of the plant is due to be completed in May 2007.