Wastewater Minimization Research Articles

A multi-contaminant transhipment model for mass exchange networks and wastewater minimisation problems

The methodology presented in the paper combines insights from Water Pinch with mathematical programming. The approach applies to mass exchanger network and wastewater minimisation problems. Its purpose is the development of targeting models at a conceptual stage where the process network is not yet developed. For wastewater minimisation, the concept of the limiting water profile is employed. The development of utility targets for multiple contaminants is developed as a mixed integer linear transhipment formulation that enables easy screening and scoping ahead of the network development. The paper describes the foundation of the model, its variants for the different problems considered, and literature examples that explain its functions. The paper reports particularly encouraging results and improvements against reported solutions in the literature.

Potential Wastewater Minimization and Pollution Control in Typical Textile Industry: Case Study

Potential Wastewater Minimization and Pollution Control in Typical Textile Industry: Case Study

An example of water conservation and wastewater minimization by membrane filtration

An example of water conservation and wastewater minimization is given. Pilot plant research and full scale plant operation are discussed.

Wastewater minimisation of industrial systems using an integrated approach

The design of an industrial water system, which makes the most efficient use of the water resources available, is a complex problem that involves different trade-offs. If we assume that no fundamental process changes can be performed (i.e. wet cooling towers cannot be replaced by air-coolers, etc.), then we can improve the efficiency of the water system through practices as water re-use, regeneration of water prior to re-use, or regeneration and recycling. The inherent combinatorial nature of the problem calls for the development of a systematic methodology that can deal with the high dimensionality of the design problem. In this paper we propose an integrated methodology for the design of industrial water systems. This approach brings the engineering insights provided by the water-pinch analysis together with powerful mathematical programming tools. The method is based on a decomposition scheme for the optimisation of a superstructure model that includes all the possible features of a design. The proposed decomposition strategy is based on a recursive procedure. With this new approach, a network featuring minimum total annualised cost can be found where the complexity of the network structure is under the control of the designer and many practical constraints can be incorporated.

The application of membrane technology for reuse of process water and minimisation of waste water in a textile washing range

Recycling of process streams and reduction of waste disposal using membrane technology in a continuous textile washing process after dyeing with reactive dyes have been investigated theoretically. A mathematical process model of a conventional open‐width washing range has been extended by membrane processes to determine the benefits and limitations of the modified washing processes. The concentrations of hydrolysed reactive dyes, sodium chloride, urea and caustic soda have been calculated with this process model. Reverse osmosis for desalination and decolourising and nanofiltration for decolourising have been implemented as membrane technology. Reusing filtered wash water in a previous wash step results in more water saving than recycling to the same wash step according to the process calculations. The total fresh water demand can be reduced by 70% and the total waste water volume by 90% compared with the conventional process. Greater reduction of fresh water use is limited by the osmotic pressure difference between the retentate an permeate streams.

Rationalizing the water use in the batch process industry

Recent years have seen an increasing environmental awareness and a considerable rise in fresh water costs and in effluent treatment and disposal costs. The need to decrease the use of water in the process industries has favored the development of water use minimization methodologies. Wastewater minimization methodologies have been developed for continuous process plants in the last years. However, there is very little work reported on the systematic rationalization of the water use in the batch process industry due to the complexity involved. In this paper a methodology is presented which identifies the in-plant water reuse opportunities, resulting in significant freshwater consumption reductions. The methodology is illustrated with a case study based on food industry.

A study on wastewater minimization in indirect electrochemical synthesis of benzaldehyde

Development of methods of pollution prevention is a strategic orientation for environmental protection. This paper describes studies on waste minimization in benzaldehyde production by using indirect electrochemical oxidation of toluene instead of the seriously polluting traditional chemical process. The new technology developed eliminates the discharge of wastewater by recycling the reactive solution and gives a higher yield of benzaldehyde.

Water and Wastewater Minimization: the Aire and Calder Project

AbstractThe reduction of the waste of raw materials at source using clean technologies, recycling, and good housekeeping has considerable benefits for both the environment and industry. A demonstration project on wastewater minimization was completed in 1995 in the Aire and Calder catchments of West Yorkshire. The findings indicated cost savings for eleven firms of over $3 million/annum and further opportunities which, when implemented, could realize another $1 million/annum. The reduction in the amount of wastewater discharged either to sewer or river was 27%, with a potential to increase to over 40%. The payback period for 63% of the waste minimization opportunities is less than one year and many involve only a small initial investment. Waste minimization when widely adopted has prospects for cutting industry's costs, reducing demand for water and reducing the volume of effluent produced.

A study on wastewater minimization in indirect electrochemical synthesis of benzaldehyde

Development of methods of pollution prevention is a strategic orientation for environmental protection. This paper describes studies on waste minimization in benzaldehyde production by using indirect electrochemical oxidation of toluene instead of the seriously polluting traditional chemical process. The new technology developed eliminates the discharge of wastewater by recycling the reactive solution and gives a higher yield of benzaldehyde.

Case study of waste water minimization at a general electric manufacturing plant

AbstractThis paper describes the process of converting an existing industrial water system at a General Electric manufacturing plant towards zero discharge. A plan to significantly reduce waste water to the publicly owned treatment works (POTW) is presented. The first phase, which should reduce water discharge by 90% compared to 1992 rates, involves three major steps. First, a vibrating membrane filter machine will be used to treat the tumbler machine waste water, which accounts for about half of the plant's total water usage. The suspended solids in the waste water will be removed and disposed of as non‐hazardous waste. The water will be reused in the tumbler room and in other processes throughout the plant. Second, effluent from the waste water treatment plant will be recycled to the maximum extent possible. Third, steps will be taken to minimize water usage in rinsing operations. When the first phase is completed, the water quality in the plant will be expected to change. In particular, the salt concentration will increase, and the temperature of the water may rise. With careful monitoring of the water quality, input rates of city water, and discharge rates, a zero‐discharge system can be defined. The key to achieving zero‐discharge will be selecting a technology to remove salts from the water. The likely candidates are reverse osmosis, electrodialysis, or ion exchange, perhaps followed by evaporation to reduce the brine volume. A preliminary design for a zero‐discharge system is presented; however, the first phase of the project will be implemented and studied before the appropriate salt‐removing technology is selected.

Wastewater minimisation

This paper addresses the minimisation of wastewater in the process industries. Targets are first set which maximise water re-use. The approach used allows individual process constraints relating to minimum mass transfer driving force, fouling, corrosion limitations, etc. to be easily incorporated. Both single and multiple contaminants are addressed. The multiple-contaminant case allows multiple constraints relating to the multiple contaminants to be allowed for. Water regeneration opportunities are also identified at the targeting stage which distinguish between re-use and recycling. Two simple design methods are presented which allow targets both with and without regeneration to be achieved in design. The first design procedure maximises driving forces in individual processes whilst the second minimises the number of water sources for each process. The approach adopted is entirely conceptually based.