You might not think the photo above was taken inside a 31 million liter per day wastewater treatment facility--and that is by design.

Sustainable water treatment design using biofilm and knife gate valves

An engineer working in water & wastewater describes a unique approach to designing sustainable—and even beautiful—sewage water treatment plants.
 
^ You might not think the photo above was taken inside a 31 million liter per day wastewater treatment facility--and that is by design.

Article by Daniel Sweet
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As an unfortunate consequence of India’s rapid economic growth and widespread urbanization of cities, the demand for drinking water and wastewater treatment stands at an all time high. Suez estimates that “an alarmingly high 70% of the urban wastewater flows untreated into the river and sea” in India, and high project costs have exasperated the problem. But thanks to the work of engineers like Sameer Sharma, India is beginning to tackle its wastewater problem in new and innovative ways.

Approach


Mr. Sameer Sharma earned his bachelor’s degree in Civil Engineering and his Master’s in Environmental Engineering & Management. In a recent interview he explained that his over 18 years of experience in the water & wastewater domain initially started with Tata Consulting engineers and with GE Water & Tecton Engineering & Construction in the United Arab Emirates. “But for the last 8 years I have been associated with Organica Water. Organica is an innovative company that employs niche technological solutions to wastewater treatment. Specifically, the company specializes in making wastewater treatment plants (WWTP) that resemble beautiful gardens—when standing in an Organica WWTP, neighborhood residents would not actually realize they are inside a facility that treats sewage.”

Organica’s unique approach to wastewater treatment aligns with their mission to “to build and operate space and energy efficient biological wastewater treatment plants that blend harmoniously into urban and residential population centers.” Mr. Sharma described the recent Bhatpara Wastewater Treatment Plant as a prime example of Organica’s approach to wastewater treatment.

India’s first green STP

In his capacity as Lead Design Engineer for Bhatpara Wastewater Treatment Plant, Mr. Sharma saw the project through from planning to completion. Bhatpara is located in West Bengal, near the end of the Ganges River. The facility there services the wastewater needs of 52,000 households and has been supplying industrial and farming water in various developing industries.

Flow control equipment facilitates the green design of the Bhatpara facility.

The facility is classified as an Organica Food Chain Reactor (FCR) facility, employing a “Fixed-Film Activated Sludge system that uses plant roots as well as engineered media to allow growth of robust and healthy biomass, effectively eliminating the incoming load in the effluent.” According to Organica’s website, “The plants – via their roots – not only provide a huge amount of surface area, but they also complete the food chain that exists in the biological reactors, thereby enabling a diverse ecology and resilient biofilm that is able to handle a higher amount of fluctuations in influent quality and quantity compared to conventional suspended or attached growth systems.” It is this system’s reliance on biological methods that allows the functional treatment facility to resemble a garden, eliminating odors and enhancing the aesthetics of the site.

Flow processes

Of course, without the flow equipment to move wastewater through the bio-film, such a site as the Bhatpara treatment plant would not be possible. As Mr. Sharma explained, “valves are integral part of WWTP flow control & aeration control processes. We work with lot of type of valves in Organica projects, including the plant at Bhatpara. The most critical component of the design are the flow control valves for aeration. In our projects we generally use V-notch type knife gate valves for this application. And of course in aspects of handling the flow of sewage we mainly use knife gate valves and gate valves.”

According to the Bhatpara website, “the flow of wastewater is measured by electromagnetic meters and level indicators, while the optimization of energy consumption requires data from dissolved oxygen probes linked to variable speed drives controlling the blowers. Pump capacity is regulated via variable speed drives and electromagnetic or pneumatic controllers which regulate valves.”

Challenges

Regarding the most common challenges faced in wastewater treatment, Mr. Sharma described three problems that plague new and old wastewater treatment plants. “High power consumption is a major challenge for WWTPs, especially when the company involved in the project aims to place energy efficiency at the center of the design. This is true for new and old plants alike. The best way to solve this problem is good design. Excellent design is crucial, and when attempting to work with defunct treatment plants, a lack of proper design at the outset will prevent engineers from bringing it back into operation. if there is no connection to an overall network, older plants are difficult to restore. Though I have observed these factors in numerous projects in my career, there are always new innovations around the corner.”

 

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