Economic Sustainability and Environmental Protection in Mediterranean Countries through Clean Manufacturing Methods

Cleaner production (CP) is a recognised and proven strategy for improving the efficient use of natural resources and minimizing waste, pollution and risks at the source where they are generated. CP is an essential part of any comprehensive environmental management system. Significant reductions in pollution loads can often be obtained at a low cost, and efficient use of resources and reduction in pollution in industrial production are clearly preferable to reliance on the end-of-pipe treatment. CP means a continuous application of an integrated preventive environmental strategy to processes, products and services to increase overall efficiency. This leads to improved environmental performance, cost savings, and the reduction of risks to humans and the environment. CP is achieved by applying know-how, by improving technology, by input substitution, by better process control and/or by changing attitudes. Investments in CP can have attractive economic benefits due to reduction of input costs of materials, energy and water, and reduced expenditures related to waste treatment and disposal. The article is focused on cleaner production concept, CP innovation development and implementation methodology, and the key issues related to cleaner production capacity building activities in a country. In addition to an example of an innovative transdiciplinary education programme, the article provides recommendations concerning the most effective ways to build basic capacity level in cleaner production.

Modern industries demand large quantities of water at purity levels that are unprecedented in industrial applications. Unless water usage is changed, these processes will not be sustainable. The key solution to reducing water usage and wastewater discharge in the ultra-pure water (UPW) plants is the development of suitable technology for water reuse and recycling. In particular, successful water conservation strategies will require innovations in a number of areas.

The ultimate solution to water conservation and sustainability for industrial use lies in some form of reuse and recycling strategy. However, the recycling process is not trivial and involves some challenges. Typically, the success in implementing recycling depends on two major factors:

Oily wastewaters are usually treated by physical, chemical and biological methods. Most conventional methods (coagulation, sedimentation, centrifugation and filtration) are not efficient in treating stable oil-in-water (O/W) emulsions, especially when the oil droplets are finely dispersed and the concentration is very low. These techniques can reduce oil concentrations by no more than 1% by volume of the total wastewater and cannot efficiently remove oil droplets below 10 μm. Hence, further treatment is needed to meet effluent standards. Membrane processes have found an increasing number of applications in the treatment of complex oily wastewater. However, sometimes it is not desirable or even possible to use a membrane system to carry out the entire separation because of the effluent nature that may cause severe fouling of the membrane. In those situations a pretreatment of the effluent by conventional methods may be suitable for a better process performance. These membrane-based hybrid processes combine a conventional process (mechanical, chemical or thermal) with a membrane separation. In this review lecture the design parameters and performance of conventional processes for the treatment of oily wastewater are summarized and several membrane hybrid processes and chosen examples are presented.

The applications, management and processing of wastewater have experienced an extraordinary transformation in the last two decades. Methods and terminology once the domain of disciplines like Chemical Engineering or Micro­biology, are incorporated in the academic programs of water/wastewater treatment. Terms like “aeration tank”, “tricking filter”, “retention time”, which often denoted simple physical unit operations in Civil Engineering, have been replaced by “reactor”,“fixed bed reactor”, “residence time ” and the concept of “waste” is being replaced by “resource” from where materials, heat or electric power, can be recovered, recycled or transformed. What used to be management and disposal of waste is being replaced by processing of a resources to obtain value added products. In this context, the configuration or topology of a conventional wastewater treatment plant is being replaced by that typical of a chemical engineering processing plant. This article gives a brief description of the evolution of wastewater engineering, and the unavoidable replacement of the horizontal geometry of the “tanks” by vertical reactors. These reactors offer a much smaller construction surface, exhibit a greater operational flexibility than conventional horizontal basins, and deliver equal or superior process performance. CUBEN (US Patent; Publication No. US-2012-0031836-A1) the first vertical nutrient removal bioreactor comes to meet those criteria. Its design allows the successful incorporation of processes like ANAMMOX eliminating one of the disadvantages of ANAMMOX: the presence of low dissolved oxygen concentrations (DO) in the effluent from the secondary treatment. The results presented herein show that DO can be virtually 0 mg/L in the anaerobic section, the elimination of nitrates in the anoxic stage exceeds 98% and the concentration of phosphorous in the effluent can be reduced to less than 1 mg/L without the addition of any salt or chemical. Optimization of the process with the optimum process control is underway.

Approximately 5.2 million pounds (2.36 million kg) of pesticides were used worldwide in 2008. In the United States alone, there are sales of more than 1,055 registered active ingredients found in 16,000 pesticides. There are negative environmental and human health consequences from the use of pesticides.

In the Mediterranean region strawberries and grapes are grown and wines produced with the use of irrigation and pesticides to maximize yields and profits. Pesticide residuals including the metals they contain, have been detected in food, fruit, juices and wines. The organic chemical architecture of pesticides is quite complex and variable. Activated carbon adsorption is the best broad-spectrum treatment available for the removal of pesticides from, fruit, juices wines as well as contaminated irrigation water. Also, activated carbon is employed in wine fining protocols to produce positive quality changes.

Environmental regulations are in place or being promulgated that will necessitate the use of activated carbon treatment in the future. The viability of activated carbon use depends on the economical regeneration of the spent adsorbent. In this paper a Low Energy Chemical Regeneration Process (LECRP) will be described. The process involves the adsorption of contaminants on activated carbon followed by regeneration of the adsorbent via Fenton based oxidations. The operational parameters of the LECRP, adsorbent selection, iron amendment protocol and optimum dose, hydrogen peroxide dose and reaction temperature are discussed.

Sanitary landfilling is the most common way to eliminate solid urban wastes. An important problem associated to landfills is the production of leachates. Because of its characteristics and because of its occurrence at remote locations, leachate needs to be treated separately from municipal or other wastewater. In this paper, the main technologies for the treatment of leachate from landfills are presented with special attention to hybrid processes, combining biological and physical treatment steps to fulfil the future demand on save, reliable and economic landfill leachate treatment. The technologies shall be grouped according to outlet requirements and inlet pollution load, pointing out the main advantages and disadvantages of each technology. This paper will summarize WEHRLE’s 25 years of experience in treating leachate in Europe, Asia and North Africa.

Textile industry consumes huge quantities of fresh water (100–150 l/kg of cotton for direct dye). During various stages of textile processing, wastewater is charged with substantial amounts of chemical pollutants. Direct discharge of these effluents into the environment causes irreversible ecological problems. Effluents coming from the different steps of dyeing cycle can be collected separately for a further treatment at source or simultaneously to be treated using a traditional treatment process. Various technologies are developed to reduce environmental damage. The most used technologies are Conventional Activated Sludge (CAS) and coagulation-flocculation (CF). However, color and salt removal from textile wastewater by means of these technologies still a major problem. Membrane processes represents a better alternative for the treatment and reuse of such wastewaters due to their capability to produce a water quality, in conformity with the more and more strict legislation in place. Microfiltration and Nanofiltration used separately or combined together have been found to be the most successful treatment methods. Various aspects will be discussed regarding the methodology and process adopted to enhance the efficiency of the treatment including the treatment at source which can be a good alternative. Also, several examples will be given.

The overexploitation of Korba aquifer mainly for irrigation purposes at a rate of 103 % caused a decrease in aquifer level in addition to its deteriorating water quality. Since July 2008, treated wastewater from Korba plant has been used to artificially recharge the aquifer at a site close to the treated wastewater plant. The purpose of this project is to develop a new sustainable water resource, to improve the groundwater bad quality and raise the piezometry of the coastal groundwater in this region.

Before starting the recharge, both groundwater and treated wastewater were monitored for their quality. The resulting mixture of groundwater and infiltrated treated wastewater is monitored since then. The changes in water quality before and after 3 years of recharge are followed for two significant parameters throughout the whole study zone: salinity and nitrates concentration, in an area of about 9 km² including both the recharge site and the treatment plant. There is no clear difference introduced by the recharge on nitrates very high concentrations as 90 % of the studied waters contain more than 50 mg L⁻¹ NO₃ unchanged and classified as bad or very bad quality waters. For salinity there is a slight decrease especially around the recharge area. In the light of these results, this ambitious project already shows positive effects for water and environmental management in the region.