Industrial Water Reuse and Recycling, an Introduction

Abstract

This chapter provides an introduction to industrial water reuse and recycling and is interlinked with several specific chapters in this field. The major issues discussed consist of usable raw water sources, water recycling and reuse applications (including quality requirements), drivers for the realization of this management option, and key success factors such as water reuse sustainability; the true value of water; financing; process design including pilot testing, operation, and maintenance; and concentrate management.

Major sources are drought-proof municipal and industrial effluents. A special resource is RO concentrate, which can be reused, e.g., for refinery coke quenching. Another option under discussion is the reuse of reclaimed water from one company by another (e.g., in industrial parks/multicompany sites where distances between the companies are relatively short). An unusual resource is river water heavily polluted by municipal and industrial effluents. A brief case study within this context is presented.

The topics of water supply security, economic benefits including brand protection and reputational risk management, as well as government policies and the green image of companies are all addressed as main drivers. Economic benefits are obtained mainly through savings of freshwater from the public supply, lower used water discharge fees, and resource recovery. Another economic advantage that is normally omitted from feasibility studies is the increase in water supply security. As an example for the implementation of government policies, the new water reuse guideline from the Indian state of Gujarat is discussed. Green image has also been identified as an important driver, as it is increasingly part of the corporate culture of many enterprises. The related benefits derive from the fact that employees are proud of a green image and are therefore more motivated. In addition, customers are increasingly willing to pay a higher price for sustainable solutions.

The major industrial applications are recycling and the reuse of various raw water sources as cooling and boiler make-up water. Within this context, several cases of industrial effluent recycling and the reuse of municipal secondary effluents are discussed in brief. Especially, in the case of the recycling of boiler make-up water, advanced multi-barrier systems (including ultrafiltration and reverse osmosis and mixed bed ion exchange) have been employed in order to meet stringent quality requirements (e.g., for silica) and subsequently to guarantee the power supply for industrial processes such as petrochemical manufacturing. With this in view, it is also very important that the reclamation plants are operated and monitored by well-trained and skilled personnel from the plant owner or a water technology specialist. Another success factor is suitable design, which in many cases is based on pilot tests. Design examples including reuse targets are described (e.g., a UF design comparison for three different reuse applications). Another important topic is concentrate management, which is discussed on the basis of disposal and beneficial reuse (including zero liquid discharge) cases. Apart from technological and operational issues, financing (e.g., public-private partnership/PPP) is addressed, which is very important for the realization of water reuse projects, especially in developing countries. Finally, the overriding importance of sustainability as a key success factor is emphasized and the conclusion drawn that water reuse and recycling solutions have to be ecologically, economically, and socially sustainable in order to provide benefits to all the stakeholders involved.