Organizations spanning a wide range of industries are faced with meeting continuously evolving environmental expectations, precipitated either by the Clean Water Act (CWA) or societal demand. Although largely written in its original form several decades ago, the Environmental Protection Agency’s CWA is the definitive standard for protecting water bodies across the United States and setting pollution control limits for wastewater.
As companies across the U.S. improve their wastewater treatment facilities to ensure they meet environmental regulations, find efficiencies, drive down costs and increase market share, they can all be byproducts of applying innovative wastewater management techniques.
Each facility’s wastewater characteristics vary based on the location and market sector in which it operates. As such, these characteristics affect wastewater treatment needs and must be taken into consideration when determining the optimal treatment method. State regulations must also be regarded to identify the appropriate design basis when building new or enhancing existing infrastructure.
Using modeling software to analyze alternatives, create “what if” scenarios and build contingency plans can support an organization in evaluating alternatives ranging from simple pH adjustment to complex complete treatment processes that allow for direct discharge. Identifying innovative, cost-effective techniques that treat wastewater efficiently and provide organizations with added benefits should be prioritized when developing a shortlist of alternatives.
Uncovering hidden energy sources in wastewater
Identifying cost-effective sources of energy to power operations is a priority for organizations. Fortunately, for those that produce significant wastewater, the wastewater itself can often be a hidden source of energy in the form of biogas.
High-strength organic streams can be treated anaerobically to generate energy for electricity or to fuel thermal processes such as boilers. Examples can often be found in food and beverage operations, including slaughterhouses and dairies, where process wastewater can be treated under anaerobic conditions.
High-strength process wastewater from food and beverage operations is typically treated using single vessel mesophilic anaerobic lagoon or tank digesters. Depending on the feed stock, alternative anaerobic digester configurations can maximize biogas production. One method is to convert existing mesophilic anaerobic digesters to a temperature-phased anaerobic digestion process.
In other applications, a manufacturer can commission the design and build of an electric generator fueled on the biogas produced by its operations, which can also provide significant hot water resources to meet heating requirements.
This wastewater management technique treats the wastewater while retaining valuable resources for reuse, supporting environmental sustainability and organizational profitability.
Identifying alternate pathways for wastewater
Manufacturers in the food industry have high organic process wastewater discharge to publicly-owned treatment works following onsite pretreatment. In some circumstances, manufacturers may reap rewards by finding alternate pathways for discharging wastewater characterized by high organic loads.
In the example of a cranberry producer that prepared for a sizeable expansion of its operation, it was determined that feeding their wastewater directly to the publicly-owned treatment works’ digester was more cost-efficient than mixing the waste with municipal wastewater. Diverting to the digester also produced biogas to be used to power the wastewater treatment facilities.
Many manufacturers in the food processing industry have historically used land application as their preferred method for disposing of process wastewater as it not only provides treatment of the process wastewater, but also provides needed nutrients for crop production and amending soil characteristics and structure. Process wastewater disposal via land application is typically restricted based on field and weather conditions and regulatory or seasonal restrictions. These restrictions may require manufacturers to store wastewater, which can impact production if storage is insufficient or lead to disgruntled neighbors if odors develop. Due to the challenge of finding land application sites, increasingly restrictive regulations and other potential issues, food manufacturers are considering alternatives for handling and treating their process wastewater.
Combining technologies in the treatment of wastewater
Moving Bed Biofilm Reactors (MBBR) were first popularized in Europe in the 1980s and 1990s. While this technology — suspending plastic forms in the shape of honeycombs in an aeration tank where biofilm can attach and accumulate — is not new, various novel applications have been recently tested.
MBBR are increasing their use in municipal and industrial wastewater treatment applications as a highly effective method to increase organic wasteload as microorganisms attach to the suspended media and grow. MBBR also have a significantly reduced footprint when compared to conventional systems, contributing to their popularity.
Both aerobic and anaerobic MBBR are used in industrial applications. An emerging trend is to combine MBBR systems to reduce footprint and maximize results. A recent pilot plant study into the combined use of an aerobic and anaerobic system at an industrial food plant in Europe showed that not only could the chemical oxygen demand (COD) be removed efficiently, but biogas could be produced.
MBBR technology continues to evolve and may be the optimal wastewater treatment method for operators looking to reduce the footprint of their wastewater treatment process and the associated maintenance requirements.
Technologies can be combined when upgrading existing facilities as well. Manufacturers often look to enhance amenities when anticipating or responding to more stringent requirements for wastewater treatment.
As an example, a recent U.S. water pollution control commission needed to enhance its tertiary filtration system to maintain compliance with effluent phosphorous permitting regulations. A novel combination of a disc filtration system with chemical conditioning was used to achieve a reduction of effluent phosphorous of up to 90% over previous levels.
Finding the optimal wastewater management technique
In its “Emerging Technologies for Wastewater Treatment and In-Plant Wet Weather Management” report, the Environmental Protection Agency lists more than 60 technologies that range in maturity from the research phase to an established process. Many of these processes are described to be in adaptive use, meaning they are continuously evolving and transforming.
The first step in understanding wastewater treatment needs is to ensure a thorough understanding of federal and local regulations as they relate to permissible levels of pollutants in effluent. Some organizations may decide to treat their wastewater to higher levels than required to anticipate increasing stringency in regulations, reduce their environmental impact or comply with societal expectations for minimizing the effect of industrial processes.
Understanding which technology or process is best suited for your facility, operational requirements and wastewater characteristics needs to be evaluated to determine the technology that will achieve the necessary results and provide added benefits to the organization such as producing energy in the form of biogas, minimizing the footprint of wastewater treatment facilities or reducing maintenance requirements.
Wastewater management is a rapidly growing and evolving field — as our understanding of the effects of pollutants on our atmosphere grows and technology improves, the number of options and level of sophistication in wastewater management techniques increases. Effective wastewater management should prioritize identifying solutions that ensure environmental responsibility, benefit businesses and improve health to create the products and energy the world relies on.
Rob Brillhart, technical advisor and technical discipline leader for wastewater engineering at Foth Environment Solutions, is a results-oriented process engineer with significant experience in biological, chemical and mechanical wastewater and water treatment facilities. Brillhart leads design teams to provide customized, cost-effective treatment solutions to municipal and industrial clients.