Physico‐Chemical Processes

Abstract

In this chapter, the physicochemical processes used in the treatment of aqueous streams such as domestic and industrial wastewaters, drinking water, contaminated groundwater, and aqueous residuals from soil treatment are reviewed. Processes that have their own chapter in the WEF review are not included in this chapter. MEMBRANE PROCESSES GENERALMembrane technology is widely accepted as a means of producing various qualities of water from surface water, well water, brackish water, and seawater.Membrane technology is also used in industrial processes and in industrial wastewater treatment, and lately membrane technology has moved into the area of treating secondary and tertiary municipal wastewater and oil field produced water (Nicolaisen, 2003). In many cases one membrane process is followed by another with the purpose of producing water of increasing purity and quality for various purposes. One type of membrane may thus enhance the function of another to meet goals ranging from disposal of wastewater to production of drinking water from alternative sources. 824 Membrane technologies offer the possibility of managing the total water resources in a region, which is of special interest in geographical areas where natural water resources are scarce. A recent project entitled Novel Technologies for Drainage Water Treatment financed by Egyptian Academy of Scientific Research and Technology (ASRT) and executed by National Research Center (NRC) comprised a detailed assessment of the desalting technologies for reclamation of agricultural drainage water (ADW) (Abulnour et al., 2003). This paper addresses the comparative techno-economics of the following systems (a) activated carbon (AC)-ultrafiltration (UF)-reverse osmosis (RO), (b) UF-electrodialysis reversal (EDR)-RO, (c) AC-ED-ion exchange (IE), (d) microfiltration (MF)-UF-RO1-RO2 and (e) slow sand filtration (SSF)-AC-IE. The results reveal that treatment scheme (d) MF-UF-RO1-RO2 provides the lowest cost production of high quality water. The most important recommendations point to the importance of field demonstration in selected locations to explore system reliability and performance under actual applications.The increasing need for water in arid regions of the world has resulted in the emergence of new water re-use technologies. The success of water re-use projects however, does not just depend on the effectiveness and suitability of the technology, but also on the presence of an institutional framework that ensures that the treated water can be distributed and used safely and efficiently. These two diverse issues were examined by MWH in projects carried out in Egypt and in the USA (Lawrence et al., 2003). One project in the East Bank of Cairo assessed the potential benefits of treated wastewater for irrigation in agricultural schemes. The project demonstrated enhanced 825 crop yields but that additional treatment of the wastewater was required to improve its microbiological quality to the standards required by both international and Egyptian legislation for safe re...

Fruit and vegetable wash-water characterization, treatment feasibility study and decision matrices

“…The three types of coagulants commonly used in C&F are metal salts (alum or ferric sulfate), polyelectrolytes (polymers) which are effective but expensive, and natural (chitosan) (Renault et al 2009;Ahmad et al 2004). C&F works on the principle of neutralizing the wash-water particles that are negatively charged, which causes destabilization of repulsive forces and permits flocculation, agglomeration and formation of particles.…”

Fruit and Vegetable Wash-Water Characterization, Treatment Feasibility Study and Decision Matrices

“…C&F is widely used in the wastewater and food industry to precipitate out particulate and dissolved matter (Hafez et al 2007;Van Haute et al 2015). The three D r a f t types of coagulants commonly used in C&F are metal salts (alum or ferric sulfate), polyelectrolytes (polymers) which are effective but expensive, and natural (chitosan) (Renault et al 2009;Ahmad et al 2004). C&F works on the principle of neutralizing the wash-water particles that are negatively charged, which causes destabilization of repulsive forces and permits flocculation, agglomeration and formation of particles.…”