Biotechnology for Zero Waste – Emerging Waste Management Techniques (Chaudhery Mustansar Hussain (editor) etc.)

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Photobiological Reactors for the Degradation of Harmful

Compounds in Wastewaters

Naveen B. Kilaru, Nelluri K. Durga Devi, and Kondepati Haritha

KVSR Siddhartha College of Pharmaceutical Sciences, Department of Pharmaceutics & Biotechnology,

Siddhartha Nagar, Vijayawada, 520010, Andhra Pradesh, India

15.1

Introduction

Advances in knowledge and developments in the industrialized parts of the world

have come at the expense of resource base and the environment. Fortunately, envi-

ronmental consciousness has also grown intensely, especially in the past few years.

Several states around the world are captivating the principal in the request of new

laws that control, and in many cases even ban, the use of hazardous chemicals.

Contaminants are not usually known as pollutants except for those damaging the

environment. Pollutant can be either natural or anthropogenic. Water biota is the

largest environmental media bearing pollutants, and present-day technologies for

the treatment of organic, inorganic, and microbial pollutants in water deal about

the sensing or pollutant degradation with many photobiological reactors.

Based on the size or the volume of wastewater from an industry, the technique to

be adopted will change. These techniques can be chemical, physical, or biological,

contingent upon the method of application and the principle of operation and

also the nature of the effluent. The pollution is usually quantified in terms of

chemical oxygen demand (COD), biological oxygen demand (BOD), and dissolved

oxygen (DO).

The categorization of techniques for the removal of the contaminants based on the

need and the available technology is as follows:

Biological treatment: Aerobic digestion (oxidation) of the effluent and anaerobic

waste minimization.

Chemical treatment: Direct chemical oxidation, photo-oxidation of the effluent,

photocatalytic oxidation and destruction of organic compounds by sonication.

Physical (thermal) treatment: Wet air oxidation (WAD), supercritical fluid

oxidation of toxic contaminant and incineration (complete combustion).

Usually, on an industrial level a combination of two or three techniques is often

required to achieve better treatability mainly due to the presence of multiple contam-

inants. The rate at which new chemical entities are exposed and unnaturally made

Biotechnology for Zero Waste: Emerging Waste Management Techniques, First Edition.

Edited by Chaudhery Mustansar Hussain and Ravi Kumar Kadeppagari.