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Recycling Wastewater Saves Money

Regardless of a manufacturer's altruistic goals to reduce their impact on water resources, they have to juggle them with daily operations in a cost-effective way. The reality of implementing industrial water recycling equipment comes down to dollars--and sense. Many manufacturers find their return on investment to be well worth the capital expense. They find savings on water purchases, water treatment, and costs associated with discharge permits and compliance infractions. These savings can actually lower overall operating costs.

Cost Savings: Purchasing Water

Manufacturers actually buy the same water back from the city after discharging it. If they recycle this water instead, they can eliminate the repeated steps of discharging and purchasing again. The volume that is purchased at a time is greatly reduced and so is the frequency of discharging. That can also remove a significant strain from the public treatment facility (POTW). More importantly, it cuts down on water costs.

Cost Savings: Pretreatment

A lot of facilities require pretreatment of the incoming city water before it can be used in their facility. Water treatment systems require consumables such as chemicals and filters in addition to resources to operate it. These are ongoing costs on top of purchasing the water. Recycled water is a higher quality than city water, in most cases, so using that water can actually eliminate the pretreatment step and associated costs.

Cost Savings: Permits and Non-Compliance

Facilities who do not meet their discharge permits can face fines and even litigation, costing them more money related to their wastewater and potentially damaging their reputation in their community and market. That can impact the bottom line. Recycling wastewater reduces significantly the risk of discharge permit noncompliance. The concentrate from wastewater recycling equipment is also a good candidate for zero liquid discharge equipment such as evaporation or solidification. Those systems eliminate the need for a discharge permit completely.

Other cost factors to consider

  • Improved sales: While it's difficult to quantify, recycling and reusing wastewater does have a positive impact on the company's public image.
  • Drought protection: Facilities located in a region that experiences drought should consider the financial benefits that a water recycling system offers during drought.
  • Operations personnel: In many cases, if a facility were to adopt water recycling, they would need to hire additional personnel to operate and maintain the system. That sounds like more money and not savings. Depending upon the vendor, however, facilities may utilize outsourcing services. Doing so lowers the overhead costs of having an operator because the employee is contracted.
  • Production impacts: The process of installing the new equipment should have little impact to production. Choose an end-of-pipe or add-on system. These are a practical and effective choice, offering a smaller footprint at a more digestible prices.
  • Extended equipment life: The high quality of the recycled water can actually extend the life of your manufacturing and treatment equipment. That can be a huge cost savings. This can be further improved by your treatment program. Is it designed with your specific equipment in mind?

Will recycling wastewater save your facility money?

Do the math:

  1. Calculate what you currently spend on water related expenses.
  2. Calculate what that cost is per gallon of water used per day.
  3. Compare the cost per gallon per day with the estimated cost per gallon to treat and recycle the same water (via your prospective vendor).
  4. Remember to consider other factors that can mean added benefits of water recycling.

ProChem strives to help their customers establish the highest level of credibility and a positive reputation within the regulatory community. Their goal is to significantly reduce the amount of fresh water that manufacturers require by providing sustainable solutions that will also benefit the customer’s bottom line.

What is Ammonia?

Ammonia (NH3) is a compound that is made of two gases: nitrogen (N) and hydrogen (H). It is colorless and has a distinct odor. Ammonia is used in many industries. In agriculture, for example, it is used for fertilizer. It is also used in food processing, metal finishing, chemical synthesis, ceramic production, oil refining, and many other industries. All of these industries produce wastewater that will contain concentrations of the Ammonia they use in their manufacturing process. Some forms of Ammonia are toxic to the environment.

What does Ammonia do in water?

When Ammonia reacts with water, it forms a weak base (pH >7). Two species of this compound exist in water: ionized NH4 (Ammonium) and non-ionized NH3 (Ammonia). It is the non-ionized form that is toxic. Generally, the equilibrium shifts toward a greater amount of non-ionized toxic NH3 with increasing pH. NH3 + H2O ↔ NH4 + OH One molecule of Ammonia reacts with one molecule of water to form an Ammonium ion and Hydroxyl ion. As the pH increases, the reaction moves more to the left, and the amount of toxic Ammonia increases. Concentrations of Ammonia (NH3) ranging between 0.5 ppm to 23 ppm are toxic to freshwater aquatic life. Ammonium is broken down by aerobic organisms to form nitrate (NO3) in a two step process: 2 NH4+ + 3 O2 → 2 NO2− + 2 H2O + 4 H+ 2 NO2− + O2 → 2 NO3− Ammonia can also complicate wastewater treatment by complexing the metals that are concentrated in the wastewater, making the metals more difficult to remove.

How is wastewater treated for Ammonia?

There are many methods for removing Ammonia/Ammonium from industrial wastewater. Some of the more common methods are listed here:

  • Conventional activated sludge: A biological treatment method. This method requires expensive capital equipment and large tanks or concrete basins.
  • Aeration: A time consuming and expensive method. This method requires a capital equipment investment and is used with conventional activated sludge to break down organic matter.
  • SBR (Sequencing Batch Reactor): This process usually has several treatment steps that may include conventional activated sludge and aeration, in addition to a third and fourth step. This method requires an expensive capital investment and most often uses concrete basins.
  • Ion-Exchange: The most economical method. This method requires lower capital investment in equipment and has a smaller footprint even for a large application. The same resins that are used to remove the Ammonia/Ammonium will also remove nitrates simultaneously.

ProChem strives to help their customers establish the highest level of credibility and a positive reputation within the regulatory community. Their goal is to significantly reduce the amount of fresh water that manufacturers require by providing sustainable solutions that will also benefit the customer’s bottom line.

Roughly half the states in the U.S. are currently experiencing a form of drought, ranging in intensity from abnormally dry to exceptional drought, according to the U.S. Drought Monitor. When drought conditions become severe, which is the case for the plains and western states, local government responds with mandates to conserve water. For example, in Wichita Falls, Texas, the entire city's water supply is now being recycled and reused. In California and Washington, residents and industrial facilities alike are under a statewide mandate to conserve water, and governors are calling for permanent behavior changes from residents.

Response to drought situations is one of the top 3 reasons why manufacturers recycle and reuse their industrial wastewater. Manufacturing facilities require large volumes of water to make their products, and they purchase that water from the city. When there isn't enough water to go around, these facilities face higher water costs. Most significantly, however, they face production losses and downtime when they don't have access to the water they need.

In the midst of a drought, requirements may be handed down to manufacturers for implementing a reuse solution or reducing their consumption by a certain percentage. This requirement may be from their corporate offices in order to mitigate losses if the situation persists, or it may come directly from the governor. Either way, the midst of a drought is not too late for implementing a wastewater recycling system. The startup of the system, however, could be delayed significantly if there isn't a sufficient amount of water available for the initial startup. This has been the case at facilities in drought areas such as Texas, where the manufacturer waits months before they have access to the volume of water they need to operate their wastewater treatment equipment.

California Drought

In areas like California, Texas, and more recently Washington state, the motivations for a long-term conservation and reuse process is high because they are currently experiencing the pain that a lack of water causes. the best time to implement a wastewater recycling system, however, is before drought conditions become severe. While the motivations at that time are less urgent, manufacturers are recognizing that the investment now will mitigate the risks later. Manufacturing facilities in states near the most severely dry states are already heeding the warning and taking action now in case the drought situation elevates in their area.

The long-term drought conditions that we're seeing are not limited to reservoirs that feed water directly into cities. The more severe problem is the depletion of groundwater that is pumped out to make up for the lack of water in the reservoir. Manufacturers recognize this as a risk factor for future production. The only way to guarantee they have the water they need is to recycle the water they do have access to. Industrial water recycling systems offer peace of mind and drastically reduce the volume of water that is consumed by a facility (this also saves money). Instead of consuming 100s of thousands of gallons of water daily, they may take in 100s of gallons weekly or even less frequently than that (to replace the concentrated water that can no longer be reused). Some facilities are even recycling their gray water and reusing it back into their manufacturing process. An Alcoa facility in Texas, for example, is installing a natural (NEWT) system that will remove biological contaminants from their gray water and then feed that treated water to their industrial water reuse system, which feeds water back into their manufacturing process. The water issue isn't a new one, and it is only becoming worse. The manufacturers who respond now will not only alleviate stress for themselves but also alleviate stress on the water resources in their area.

ProChem strives to help their customers establish the highest level of credibility and a positive reputation within the regulatory community. Their goal is to significantly reduce the amount of fresh water that manufacturers require by providing sustainable solutions that will also benefit the customer’s bottom line.

What are Ion-Exchange resins?

Ion-exchange resins are small, porous beads that are negatively or positively charged, allowing them to grab onto ions (contaminants in the water) that are attracted to that charge. These resins are solvents (insoluble in water), and they range in diameter from 0.3 to 1.5 mm. Resin is placed in a vessel, usually called a column, and submerged in water where it forms a layer on the bottom called a bed. The bed absorbs water and swells when it is first immersed. Immersion conditions the resin. When the resin is fully conditioned, the beads contain 50 - 70% water.

Wastewater is passed through the resin columns while the resin bed is gently agitated. The agitation allows the water to flow uniformly around the resin beads. The agitation actually increases the amount of surface area that comes in contact with a wastewater, which increases the likelihood that the porous openings will come into contact with ions. Imagine the resin bead as a ball covered in holes. As the ball rolls and bounces in the wastewater, its holes become exposed to the particles suspended in the water. Due to the charge, if the ions come into contact with the resin, they will be attracted to it and become trapped in the pores.

There are two main types of resins: Cationic and Anionic. Cationic (pronounced like "kat-eye-on") resins are negatively charged and remove positively charged cations. Here are some examples of ions that can be removed by Cationic resins: Chrome (Cr), Nickel (Ni), Zinc (Zn), Copper (Cu), Lead (Pb), Calcium (Ca), and Ammonia (NH3).

Anionic resins are positively charged and remove negatively charged anions. Here are some examples of ions that can be removed by Anionic resins: Chlorides (Cl), Sulfates (SO4), Nitrates (NO3), Carbonates (CO3), Phosphate (PO3), Bromide (Br), and Hydroxide (OH).

Why use Ion-Exchange resins for wastewater treatment?

Ion-exchange resins fill a unique niche when it comes to wastewater treatment. They are ideal for treating waste streams that are lower in total suspended solids (TSS) and in contaminant levels than those treated with a chemical program. Other advantages include:

  • No sludge generated. If the wastewater being treated is from an electroplating operation, for example, sludge is considered F006 hazardous and can be very expensive to haul off.
  • Less labor intensive than chemical treatment.
  • Columns ship easily and are usually considered non-hazardous.
  • Much smaller space requirements than a chemical treatment system. A system that treats 10 gpm - 20 gpm can easily fit in approximately a 4 x 10 footprint.
  • Lower overall operation cost.

There are several suppliers that offer ion-exchange resins and the columns. The simplest way to use ion-exchange is by utilizing a column exchange program, which is available through certain vendors. These programs allow you to exchange your exhausted columns for regenerated ones without impeding your wastewater treatment process or production. Contact an industrial water treatment company who can help you select the most effective resin, install the system, and set up a routine column exchange program that works for your facility.

ProChem strives to help their customers establish the highest level of credibility and a positive reputation within the regulatory community. Their goal is to significantly reduce the amount of fresh water that manufacturers require by providing sustainable solutions that will also benefit the customer’s bottom line.

What is Jar Testing?

Jar testing is a method for determining the treatment method that will be used when treating wastewater. Specifically, it helps to determine which chemicals will be needed and the proper dose rates for those chemicals. Jar testing is essentially a miniature batch treatment tank with all the variables under control of the operator. It usually consists of a "jar" or beaker of a known volume and a variable speed mixer.

The mixer can be as simple as a glass rod stirred by hand, a laboratory stir plate with a magnetic stir bar, or a motor driven metal impeller (similar to the mixers found in many wastewater treatment reaction tanks). It is also a good idea to have a pH meter for jar tests, as many of the reactions that occur during treatment require specific pH ranges.

Water Treatment Jar Test

How do you Jar Test?

As with any experimentation, it is good practice to take notes, keeping track of the additions and observations you make during the testing. A water sample should be taken from the equalization tank (a holdingtank where all wastewaters are intermingled before being pumped to the wastewater treatment system). You should sample a specific volume, usually a liter. Next, agitate the water in the jar, and measure the pH. In waters that may contain cleaner as well as dissolved metals, it is common to lower the pH to 2.5 - 3.0 with dilute sulfuric acid if it isn't already at the required pH.

Once the pH is lowered, you should being adding chemicals. Most often, coagulant is added at this stage. Coagulant is measured in parts per million (ppm), which is one milligram of something in one liter of water. In this case, one ppm is a one hundredth of a milliliter in one liter of water, with 1 milliliter in 1 liter of water equaling one thousand ppm. Coagulant addition may range from 1 to several thousand ppm depending on what is being treated. Allow the coagulant to mix in the water.

Next, the pH should be raised using dilute sodium hydroxide, usually to a range of 9.0 - 10.0. If required, because of complexors that might be present in the water tying up the metals, a metal precipitant can be added at a dose of 50 - 200 ppm. When metal precipitant is mixed well, the polymer should be added. In water being treated for metals, an anionic polymer is commonly used. Polymer addition should be made with good mixing to evenly distribute the polymer throughout the water. Mix for 30 to 60 seconds, then turn off the mixer. A heavy precipitate or floc should form and begin to settle to the bottom of the jar.

At this point, the jar test is complete, and a sample should be filtered and then taken to a treatability laboratory for analysis.

ProChem strives to help their customers establish the highest level of credibility and a positive reputation within the regulatory community. Their goal is to significantly reduce the amount of fresh water that manufacturers require by providing sustainable solutions that will also benefit the customer’s bottom line.