Wastewater reuse plants

Wastewater reclamation and reuse plants have been constructed and operated around die world. Table 1.10 shows large wastewater reuse plants. RO membrane is necessary for wastewater reclamation to make the water quality reusable. The largest RO plant is operated in Kuwait since 2005. 

A notable example of controlled water reuse was utilization of secondary sewage effluent from the Back River Wastewater Treatment Plant in Baltimore by the Sparrows Point Works of Bethlehem Steel (6). The Sparrows Point plant was suppHed primarily by weUs located near the brackish waters of Baltimore harbor. Increased draft on the weUs had led to saltwater intmsion. Water with chloride concentration as high as 10 mg/L is unsuitable for many steelmaking operations. Rollers, for example, are pitted by such waters. However, treated effluent from the Back River Plant can be used for some operations, such as coke quenching, and >4 x 10 m /d (10 gal/d) are piped 13 km to Sparrows Point. This arrangement has proved economical to both parties for >40 yr. 

One unique application reused community tertiary-treated wastewater as plant cooling water in a major chemical complex in Odessa, Texas. 

Cazurra T (2008) Water reuse of south Barcelona s wastewater reclamation plant. Desalination 218 43-51... 

Juang LC, Tseng DH, Lin HY (2007) Membrane processes for water reuse from the effluent of industrial wastewater treatment plant a study on flux and fouling of membrane. Desalination 202 302-309... 

Storage Design for Maximum Wastewater Reuse in Batch Plants... 

Majozi, T., 2006. Storage design for maximum wastewater reuse in multipurpose batch plants. Ind. Eng. Chem. Res., 45(17) 5936-5943. 

Two formulations were derived. The first deals with minimising the amount of effluent produced from an operation where wastewater can be reused in product formulation and the plant structure is known. The minimisation is achieved by scheduling the operation in such a manner as to maximise the opportunity for wastewater reuse. The second deals with the synthesis of a batch process operating in zero effluent mode. The formulation determines the number and size of processing and storage vessels as to minimise the cost of the equipment and the amount of effluent produced from the resulting operation, while achieving the required production. 

The zero effluent synthesis formulation was applied to a second illustrative example. In the example the number of processing units and the size of the central storage vessel were not known. The resulting plant required only 3 processing units and no storage vessel. The resulting schedule produced 68% less effluent than the same operation without wastewater reuse. 

Although a number of precautions have been mentioned for the control of sulfide by precipitation as FeS, this methodology is often considered not only acceptable but also cheap and efficient. Added iron salts may also be reused in the treatment process. Under aerobic conditions in the wastewater treatment plant, the amorphous FeS is fast oxidized, and the iron can be used for chemical removal of phosphate. 

Reuse of wastewater treatment plant effluent as cooling water, as scrubber water, or as plant makeup water. 

The El Segundo, CA, Chevron refinery takes a further step in water reuse [76]. It receives 16,300 m /day of reclaimed water to feed its boilers. Microfiltration (ME) and RO are used to treat secondary effluent from the Hyperion Wastewater Treatment Plant to provide low-pressure boiler feedwater while a second pass RO is used to produce high-pressure boiler feedwater. 

The discharge from both domestic and industrial wastewater treatment plants (for example, from activated sludge processes) has been a low-cost source of makeup for cooling systems for many years. Efforts to reuse water continue to gain momentum for environmental conservancy and economic reasons, but the fact that secondary use waters are, by definition, of a lower grade than other supply sources inevitably means an increased risk of deposition or fouling problems in the cooling system. 

Due to the general implementation of improved regulatory measures around the world today, most discharge streams from wastewater treatment plants have been subjected to good treatment processes and would be of a quality suitable for return to a stream or other water course. Therefore the reuse of such water for cooling system makeup often is economical. 

Among the different wastewater streams, the amount of effluents from municipal wastewater treatment plants (WWTPs) has increased during the last decades. Since more stringent regulations on environment protection are adopted worldwide, the quality of WWTP effluents must be improved before discharge, to preserve natural water resources from contamination at the same time, the generation of these huge quantities of wastewaters to be processed, has raised questions on the opportunity to consider them as a potential alternative water resource for some human activities [18]. Therefore, wastewater purification and reuse have twofold major impacts... 

Figure 1.10 Wastewater reclamation and reuse plant in Singapore (24,000 m /day).

Figure 1.12 RO portion of wastewater reclamation and reuse plant in Kuwait.

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