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CHAPTER 13

Zero Liquid Discharge Solutions

Shrikant Ahirrao
Praj Industries Limited, Pune, India

13.1 INTRODUCTION

India is a large and diverse country. Its land area includes regions with some of
the world’s highest amounts of rainfall, very dry deserts, coastline, alpine
regions, river deltas, and tropical islands. In the past several decades, industrial
production has increased in India because of an increasingly open economy
and a greater emphasis on industrial development and international trade.
Water consumption for industrial use has consequently risen and will continue
to rise. Ecological issues are an integral and important part of the environmen-
tal issues challenging India. Poor air quality, water pollution, and garbage all
affect the quality of food and the environment necessary for ecosystems to
thrive. India is recognized as having major issues with water pollution, pre-
dominantly because of untreated industrial wastewater and failure to achieve
zero liquid discharge (ZLD), defined as no effluent discharged into surface
waters from industry (discussed in the following section).
Environmental concerns are steadily increasing, and regulatory authorities
are constantly tightening the environmental standards, insisting that industries
adopt advanced wastewater treatment technologies, including ZLD solutions.
Today industry is primarily concerned with developing ZLD solutions
that address some of the following challenges:
1. Innovative and customized solution offerings
2. Highly corrosive effluent and the selection of metallurgy
3. Recovery of pure process condensate for reuse and recycling
4. Operating temperature and pressures and scaling and fouling tendency
5. Continuous operation of the system with minimization of cleaning-
in-place (CIP) effluents
6. Selection of appropriate type of evaporator effects in multi effect
evaporation system
7. Optimization of CAPEX and OPEX for ZLD solutions.
This chapter discusses solutions aimed at achieving ZLD. If implemented
properly, ZLD has the potential not just to alleviate concerns of effluent

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