Academic journal article Journal of Environmental Engineering and Science

Scope of Improvement of Treatment Capacity of Activated Sludge Process by Hybrid Modification

Academic journal article Journal of Environmental Engineering and Science

Scope of Improvement of Treatment Capacity of Activated Sludge Process by Hybrid Modification

Article excerpt

Abstract: Activated sludge process is widely used for wastewater treatment throughout the world with various needful modifications. The hybrid modification of conventional activated sludge process utilizes a suspended media of appropriate inert material or fixed surface that serves as carrier material for growing active microorganisms on its surface. As a result the carrier media allows the biological reactor to operate at a higher biomass concentration, compared to the conventional activated sludge process. The hybrid modification of conventional activated sludge process can be configured either to provide additional capacity for biochemical oxygen demand (BOD) removal or to facilitate nitrogen control. The process is ideally suited for upgrading the existing system with a nominal modification. The present paper summarizes various research work towards the hybrid system to review the requirements and scope of modification, development and evolution of the hybrid modification. The review concludes with an assessment of financial viability of hybrid modifications.

Key words: activated sludge process, hybrid modification, suspended media, fixed surface, BOD removal, nitrogen control.

Resume : Le procede de traitement par boues activees est largement utilise pour le traitement des eaux usees dans le monde, requerrant cependant plusieurs modifications. La modification hybride du procede traditionnel de traitement par boues activees utilise un materiau inerte adequat en suspension ou une surface fixe qui sert de matiere de charge pour la croissance de microorganismes actifs sur cette surface. Il en resulte que la matiere de charge permet au bioreacteur de fonctionner a une concentration de biomasse superieure a celle du procede traditionnel de traitement par boues activees. La modification hybride du procede traditionnel de traitement par boues activees peut etre configuree pour fournir une capacite additionnelle pour l'elimination de la DBO (demande biochimique en oxygene) ou pour faciliter le controle de l'azote. Le procede est parfaitement adapte aux mises a niveau des systemes existants par une modification nominale. Cet article resume les divers travaux de recherche sur le systeme hybride afin de revoir les exigences et la portee des modifications, du developpement et de l'evolution de la modification hybride. La revue se termine par une evaluation de la viabilite financiere des modifications hybrides.

Mots-cles : procede de traitement par boues activees, modification hybride, materiau en suspension, surface fixe, elimination de la DBO, controle de l'azote.

[Traduit par la Redaction]

Introduction

Over the last 50 years, not only regulations have undergone a vast change, but also both conventional technologies have been further refined and new technologies developed to meet increasingly stringent water quality criteria. So, the present challenge is to follow-up new requirements in both an environmentally acceptable and cost effective manner. Also, growing populations and increased industrial production are exploiting the capacity of existing treatment plants to their limits. At the same time, discharge standards are becoming more stringent than ever before, as people realize the importance of a clean and healthy environment. The capacity and performance of a municipal wastewater treatment facility is a variable target, which is influenced by existing population and industrial input, projected growth rates in both of these variables.

The upgrading of an existing activated sludge plant to provide increased treatment capacity can be an expensive proposition. Traditionally, it is involved with the installation of additional aeration basin and (or) clarifier volume. This approach requires a significant time period for pre-engineering studies, approval, design, tendering, construction and commissioning. In some cases, the additional space for physical expansion may not be available. …

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