미 버지니아주 호프웰에 위치해 하루 2700만 갤런을 처리하는 호프웰 하수처리시설(HRWTF)이 곧 새 기술을 받아들인다. 이 기술은 총질소량(total nitrogen, TN) 부산물을 지역 규제 준수 수준으로 운용하기 위해 고율의 용존공기부상법(dissolved air flotation, DAF) 시스템을 이용해 유동상 생물 반응조(moving bed bioreactor, MBBR)를 두 배로 만든다.

하수처리 솔루션 설계업체이자 제조업체인 World Water Works(WWW)사가 제공한 이상적인 MBBR-DAF™ 시스템은 호프웰 시와 WWW팀, HDR 엔지이너링, PC 콘스트럭션, Heyward사 간의 설계-구축 민관협력을 통해 선정되었다.

HRWTF는 산업에서 배출된 하수의 80퍼센트 이상이 모여 있는 독특한 상황에 놓여 있다. 이 하수는 암모니아 산화 박테리아(AOBs)와 아질산염 산화 박테리아(NOBs)로 알려진 독소를 포함한다. AOBs와 NOBs는 하수로부터 질소를 제거하는 전통적인 질화탈질(nitrification/denitrification) 과정을 책임진다. 문제를 해결하기 위해 HRWTF는 광범위한 평가와 WWW의 이상적인 MBBR-DAF 시스템을 포함한 다양한 기술을 이용해 처리가능성 시범연구를 실시했다.

 

 

Hopewell Regional Wastewater Treatment Facility (HRWTF), a 27-million-gallons-per-day (MGD) utility located in the city of Hopewell, Va., will soon receive a new technology that couples a moving bed bioreactor (MBBR) with a high-rate dissolved air flotation (DAF) system to help bring its total nitrogen (TN) waste load into compliance with local regulations.

Provided by World Water Works, Inc. (WWW), a designer and manufacturer of wastewater treatment solutions, the Ideal MBBR-DAF™ system was selected through a design-build public-private partnership (PPP) between the city of Hopewell, and the team of WWW, HDR Engineering (HDR), PC Construction (PC), and Heyward Inc.

HRWTF has a unique situation where the source of more than 80 percent of its wastewater comes from industry -- some of which contains known toxins to ammonia oxidizing bacteria (AOBs) and nitrite oxidizing bacteria (NOBs). AOBs and NOBs are responsible for the traditional nitrification/denitrification process of removing nitrogen from wastewater. To solve the problem, HRWTF conducted an extensive evaluation and pilot treatability study of various technologies including WWW's Ideal MBBR-DAF system.

After over six months of pilot testing, it was clear that the Ideal MBBR-DAF system led the field by consistently bringing TN levels of the facility to the future targets while being very robust against the harder-to-degrade industrial wastewater sources being treated. Further, WWW and HDR developed a creative design to reduce capex and provide a robust solution.

HRWTF evaluated the PPP thoroughly through independent parties and found that it not only offered the ability to implement the project faster but also at a substantially lower cost than the traditional design-bid-build path. "This PPP is a win-win-win," said Daniel Dair, WWW technical manager. "HRWTF gets a state-of-the-art system with a binding performance guarantee from one source; the price is not only lower than anticipated, it is also guaranteed; and the local waterways and Chesapeake Bay win with better water quality sooner."

The project is in full swing and is expected to be completed by 2016.

 

[출처 = waterworld / 2014년 9월 12일]