For those employed in the beverage, dairy, food, pulp and paper and other industrial fields, the concept of sustainability is becoming a greater operational concern with every passing day.
According to the Merriam-Webster Dictionary, sustainability is “a method of harvesting or using a resource so that the resource is not depleted or permanently damaged.” Wikipedia offers the following definition of sustainability from an environmental perspective: “the potential longevity of vital human ecological support systems, such as the planet’s climatic system, systems of agriculture, industry, forestry, fisheries, and the systems on which they depend.”
From a more focused industrial perspective, it could simply refer to the ability of a production plant to continue competitively producing its products throughout the next 25 years. Today’s challenge is to continue production activities in a global environment with depleting resources, seemingly endless energy cost increases, and external/international competition.
As a waste treatment specialist, there are a number of things you can do to increase the sustainability and competitive ability of your company. This can be as simple as conducting a waste minimization audit that examines and scrutinizes things such as water, chemical, and energy usage and routine reviews of air, wastewater and solid waste generation and disposal. The adjacent “Waste Hierarchy” graphically presents a commonly referenced table for handling wastes from a sustainable perspective.
Some notable but common examples of sustainable waste treatment practices include the following:
Anaerobic Treatment of High Strength Wastewater
Decreased water usage in production can lead to higher concentration wastewater. If biodegradable, anaerobic treatment of the high strength wastewater can lead to the production of biogas with minimal excess sludge production and little energy usage. The net result will be lower water usage and costs, less sludge handling and costs, and possible revenue from biogas use.
Conversion of Aeration Systems to Fine Bubble Diffusion
Many existing aerobic wastewater treatment systems use inefficient methods of transferring oxygen/air into the wastewater, such as coarse bubble diffusion. The conversion of such aeration systems to fine bubble diffusion will reduce power consumption significantly and reduce operating costs.
Anaerobic Digestion of Waste Organic Solids
Waste organic solids, ranging from bottle labels to food scraps to biological sludge, can be anaerobically digested to stabilize the material and produce biogas. As with the high strength anaerobic wastewater treatment approach mentioned above, the net result will be reduced sludge handling costs and the creation of a more disposable material.
Increase Efficiency of Mixing Systems
Many waste management systems employ basins and tanks with mixers. Although the reasons for mixing are varied, in many cases the actual performance of the mixing system is inefficient and does not meet design standards. Checking the efficiency of the mixed system and adding baffles or reorienting the inlets and outlets often improves mixing to the point where less energy is required at an increased performance level.
Additional Membrane Treatment
Some production plants are required to provide a high degree of treatment to meet discharge regulations. For these systems, or in the case where water resources are extremely limited and priced accordingly, some additional membrane treatment will convert the effluent of the treatment system to a recyclable resource. The clean effluent can be used as cooling tower or boiler makeup, as site irrigation water, for dust control, or even for toilet system water.
The sustainability movement only shows signs of strengthening as resources dwindle and competition increases. Consider employing these sustainable waste management practices to save money, improve corporate citizenship, and reduce discharge costs!
|Reduce overall consumption|
|Selective consumption (maximize the use of secondary material)|
|Elimination of waste production|
|Source reduction or minimization|
|Reuse of materials|
|Internal recycling of material|
|Material sent for recycling|
|Recovery of energy and heat|
Courtesy of “The Sustainability Guide” published by Building-In Sustainability.