When you're developing a treatment strategy for your industrial wastewater, one of the first choices you'll make is whether to use chemical or biological treatment. These two processes use quite different techniques to treat wastewater streams filled with varying types of contaminants. The guide below will discuss chemical vs. biological wastewater treatment methods in more detail to help you make an informed decision.

Why is proper wastewater treatment essential? Worldwide, especially in developing countries, about 80% of wastewater goes back into the environment without treatment — sometimes causing environmental damage and sickening local populations. In contrast, proper wastewater treatment provides several valuable benefits, including:

Chemical and biological treatments both remove harmful pollutants in wastewater, but each process is ideal for different contaminants. A facility will need to choose the optimal treatment for the contaminants it deals with. 

Chemical treatment of wastewater uses chemical reactants to break down pollutants. It is ideal for wastewaters with high chemical toxin contents, such as the wastewaters from chemical or pharmaceutical manufacturing, pump and paper mills, laboratories and textile manufacturers. It is also optimal for removing the heavy metals found in mining wastewater. The chemical effluent treatment plants (ETPs) that treat these wastes use chemical treatment methods. 

Wastewaters that contain toxic substances, especially toxic soluble metals, generally require chemical treatments. Any industry that uses raw materials from the earth — including industries like mining, steel manufacturing, and oil and gas extraction and refining — will produce wastewater with toxic soluble metals. These industries are more likely to use chemical treatment.

Below are a few of the common contaminants chemical waste management treatments can remove:

Chemical treatment may be a straightforward or complicated process depending on the contaminants in the water and the chemical reactions that take place. Most wastewater chemical treatment involves the following steps:

Depending on the contaminants, the wastewater may undergo intermediate steps, such as pH adjustments to enhance coagulation or temperature adjustments to optimize chemical reactions. 

The main alternative to chemical wastewater treatment is biological wastewater treatment. Instead of using chemicals to break down waste, this process uses beneficial microorganisms to biodegrade waste material. 

Biological wastewater treatment is best at removing contaminants that biodegrade easily. Compounds with simple molecular structures – monomers and dimers, rather than complex polymers – are easiest for microorganisms to digest. Below is a list of contaminants biological wastewater treatments commonly remove:

Like chemical treatment, biological wastewater treatment often includes several steps. Below are a few standard biological treatment methods:

The costs of chemical and biological wastewater treatments depend on a wide range of factors. A treatment that is efficient and economical in one facility may not work well in another. Below are some of the factors that go into determining wastewater treatment costs:

Unlike biological wastewater treatments, chemical treatments use chemical reactants. Much of the cost associated with chemical wastewater treatment is the cost of purchasing the reactants. The volume of wastewater, the pollutants' complexity and the amount of reactant necessary will help determine the total expense. 

Biological treatment generally uses large tanks or lagoons, often with moving mechanical parts like aerators, diffusers or thousands of media pieces to facilitate bacterial growth and waste digestion. Much of the cost of running a biological wastewater treatment plant comes from installing the tanks and equipment. 

Because wastewater treatment plants tend to be large and complex, they require a tremendous amount of energy to run. All that energy adds up to substantial utility bills. Across the United States, municipal wastewater treatment plants typically consume about $2 billion in electric costs, and energy costs tend to make up anywhere from 25% to 40% of a plant's total operating budget. On average, wastewater treatment represents 1% to 3% of the energy use of most countries. Figures may differ somewhat for industrial operations, but energy still constitutes a significant expense.

A wastewater treatment plant needs trained, experienced people to run it. Paying technicians and plant managers their salaries and benefits is another part of the cost of operating a wastewater treatment plant. In 2018, plant operators in the United States earned a median annual pay of $46,780.

A wastewater treatment plant requires regular maintenance to ensure high performance and functionality. Membranes may become fouled and need cleaning, or parts may break down and require replacements. Ongoing maintenance costs contribute to the expense of running a wastewater treatment plant. 

How should you determine the right treatment method for your wastewater streams? Below are a few steps to get you started:

The type of contaminants in your wastewater is one of the most critical factors to consider. Chemical treatment and biological treatment each remove certain types of contaminants, so you'll need to select the treatment method best suited to your wastewater. If your wastewater contains high concentrations of toxic materials like heavy metals, you'll likely need chemical treatment. If your wastewater contains high concentrations of biodegradable material like biosolid waste, you'll want biological treatment instead. 

Because chemical treatment tends to work better on more complex molecules, some facilities also deploy a combination of chemical and biological processes. They use chemical processes first to break down the complicated molecular structures and switch to biological processes when the molecules become smaller and easier to biodegrade. 

Additionally, you'll need to evaluate the concentrations of contaminants in your wastewater. Denser contaminant levels will require more chemicals or more strenuous biological treatment levels. 

Your choice of wastewater treatment may depend on the space and utilities available. If building a sprawling, multi-tank complex on a small amount of land is not possible, consider more compact treatment operations instead. And if electricity is at a premium because of high demand, you'll want to invest in more energy-efficient methods. 

Federal and local regulations may govern how low contaminant levels must be when you discharge treated wastewater back into the environment. You may need a specific type of wastewater treatment or a service that can reliably remove the correct volume of pollutants.

Even with all the information you have about treatment options, your company may be uncertain about how to choose the right industrial wastewater treatment method. Consulting with a waste disposal company is an excellent solution. Professionals in the field know the details and advantages of different processes and are intimately familiar with the regulations that govern your area and industry. They can help turn a complicated decision into a straightforward one. 

To provide chemical or biological treatment for your facility's wastewater, contact the experienced professionals at VLS. We are a full-service environmental company with the ability to handle all residual waste streams, and our wastewater treatment facility offers reliable, responsible and environmentally friendly treatment solutions for industrial wastewater. 

When you work with us, you'll gain peace of mind of knowing you're engaging in sustainable practices, remaining compliant with regulations and procuring efficient, effective wastewater treatment services. We can even take a sample from your waste stream and have it analyzed for free in the Pennsylvania Department of Environmental Protection state-certified laboratory to give you the most accurate picture of your wastewater composition and treatment needs. 

Contact us today for a free wastewater treatment quote.