What is inorganic material in wastewater? Human waste, food scraps, and plants are organic in nature. They break down easily. Some materials that make their way into wastewater are not organic and do not decompose. Inorganic materials include soaps, nitrates, chlorides, phosphates, heavy metals, etc.

Some of the inorganics found in wastewater include cadmium, copper, lead, and mercury (heavy metals). They can come from older homes with copper piping and lead solder. There are non-metallic salts like arsenic and selenium. They can come from manufacturing plants, improperly disposed cleaning products, paints, and items like deicing products that are picked up in stormwater run-off when sewers and stormwater drains are connected.

Wastewater inorganics require careful removal to get them out of the wastewater before it’s released back to bodies of water or water treatment plants for community water supplies. What are the best ways to remove them?

Start With Trash and Screen Rakes

Wastewater is 99.9% water and 0.1% organic matter, inorganic matter, and microorganisms.  It’s that 0.1% that wastewater treatment plants must remove before releasing it to rivers, ponds, lakes, or oceans or a water treatment plant that serves a community.

Some inorganic materials in wastewater may be large enough to remove using screens. This includes things that never should have been flushed or allowed to get down the sink, such as plastic tampon applicators, jewelry, condoms, toys, and plastic wrappers.

A screen will capture those items before they get into the wastewater treatment stages. Trash rakes remove them from the screens to ensure wastewater flow isn’t impeded. Screens can start with a large mesh and get smaller to ensure items of varying sizes are captured in this process. All of these items can then go to landfills for proper disposal.

Sequencing Batch Reactors Are Essential in a Wastewater Treatment Plan

A Sequencing Batch Reactor (SBR) offers a continuous feed process to help with the removal of nitrogen and phosphorus. Using aeration, oxygen helps break down organics. As the wastewater is aerated, microorganisms get to work feeding on nitrogen/nitrates and producing sulfate. Some wastewater treatment plants can capture methane produced during wastewater treatment and use it for heat

Sludge (solid materials) sinks to the bottom and can go to landfills or be turned into fertilizer for forests and fields. Sludge pumps are used to help get the sludge out of the tanks.

Enhance Your Systems Precision and Stability With SharpBNR

Your plant has workers, but it’s hard to predict how a day will go. Heavy rainfall, holidays, and even the pandemic can change how much wastewater flows from area homes and businesses. During the pandemic, more people worked from home and school children stayed home. People were home and using the toilet and sinks all day, which changed peak hours for higher flow rates.

There will be moments when flow rates increase and decrease. A SharpBNR control system continuously monitors for fluctuations and adjusts equipment to maintain proper operation. If there are issues that require human intervention, alerts go out.

Industrial Plants Should Consider Treating Their Wastewater Before It Goes to Sewers

If there are several industrial plants in your district, it’s time to consider having them put in water treatment equipment that pre-treats the factory’s wastewater before it goes to the sewer lines.

Package treatment plants are a great solution for industrial companies. The all-in-one plant includes screening, aeration, clarification, disinfection, and sludge removal in one tank. It’s an easily installed single system that doesn’t require a lot of space, making it ideal for established plants.

Explore the Pros and Cons of the Most Popular Removal Methods

1. Adsorption

Polymeric adsorbents are one option for removing inorganic matter from wastewater. They’re generally low-cost and do a good job of removing heavy metals and balancing pH levels. Some of the most popular polymeric adsorbents include clay, zeolites (aluminosilicates often used in dietary supplements), and nanometal oxides.

Using the same process, there is ongoing research regarding the cellular structure of algae to help remove inorganic materials. Algae feed on nitrogen and phosphorus to grow. As algae grow steadily, they can become useful in other areas like algal biofuel.

2. Bioelectrochemical

One area that’s gaining interest is bioelectrochemical systems. The energy present in organic matter becomes useful in generating power that oxidizes the pollutants. As contaminants are removed, electricity is generated. That electricity can change heavy metals like chromium from a soluble state to an insoluble one, making it easier to remove. With this process, denitrification can occur at a lower cost than some of the other methods.

3. Chemical Precipitation

One option for treating inorganic materials is to add a chemical reagent to remove inorganics. This isn’t an ideal option as some of the reagents that are commonly used include ferric salts or lime. It ends up impeding sludge treatment, making it an ineffective option in any wastewater that also has organic materials.

4. Ion Exchange

Ion exchangers replace calcium and magnesium with sodium ions. The process starts by passing wastewater through an anionic exchange resin that replaces the anions with hydrogen and hydroxide ions and creates molecules of water and then introduces sulfuric or hydrochloric acid.

The ion exchange resin layers are usually set below the flow of water. They can end up getting clogged, which isn’t ideal and needs to be addressed or you’ll end up with a malfunctioning ion exchange.

5. Membrane Filtration

Ultrafiltration uses membranes to filter out inorganic materials. Wastewater is pushed through the filters using pressure. It’s an effective system, but it does reduce water pressure. It’s ideal for filtering colloidal and dissolved materials.

6. Reverse Osmosis

Reserve osmosis requires wastewater to pass through a semipermeable membrane at high pressure, and that pressure is created using a pump. This causes contaminants within the wastewater to dissolve and separate from the water. The clean water continues flowing, but the contaminants are trapped in the membrane. This system is one you often see in homes.

Work With an Expert in Clean Water to Get Desired Results

Effective inorganic material removal starts with the right equipment. Lakeside Equipment has been designing, installing, upgrading, and maintaining water treatment solutions since 1928. We have close to a century of experience consulting with water treatment engineers, managers, and operators to ensure equipment does everything they need.

When you upgrade your wastewater system to meet new guidelines or need to improve your system’s efficiency or capacity, it’s important to work with a wastewater treatment specialist who can implement upgrades that meet your requirement without greatly increasing your budget. People in your district won’t appreciate a giant increase in their water bills, so you have to carefully plan upgrades and take advantage of grants.

Reach our experts by phone or online. Our online contact form is available 24/7 and makes it easy to get hold of Lakeside Equipment’s experts.

People often flush items that never should have been flushed. Menstrual products, diapers, baby wipes, condoms, and even accidental children’s toys can end up in the sewers and septic tanks and into your wastewater treatment plant.

Items like paper towels, baby wipes, and even the supposedly flushable wipes or cat litter can collect grease that goes down drains while washing dishes. It creates the fatbergs that create blockages in sewers.

Fatbergs can be gigantic and create major headaches for wastewater workers. The biggest fatberg in the U.S. to date was found in Detroit and measured 6 feet tall, 11 feet wide, and 100 feet long. This isn’t the largest fatberg found in sewers. One found in London was estimated to weigh 130 tons and stretched for over 820 feet.

It’s not just things that people put down the drain or flush in a toilet. If your district has a combined sewer overflow, which combines stormwater runoff systems and the sewer system, you’ll also end up with trash, branches, leaves, and other debris. All of these items can do a lot of damage by clogging channels and lines or getting caught on equipment. It’s important to screen incoming wastewater and septage to remove them.

Wipes Are a Costly Problem

A 2019 NACWA study looked at the added cost that baby wipes place on different states’ wastewater districts. In California, the cost came to more than $47 million. New York was second with added costs of almost $38 million. Illinois, Ohio, and Texas rounded out the top five with respective totals of $29 million, $25 million, and $25 million. In all, wipes add more than $440 million in operating costs to wastewater treatment plants throughout the country.

People in your district may not have any idea of the problem they’re creating while using wipes. Many are marked as flushable products, just like toilet paper, yet they do not dissolve effectively. Ryerson University looked at 101 brands of wipes, 23 of which were labeled flushable, and none of them broke down enough to prevent clogs.

Once in the sewer lines, wipes can increase operating costs by creating fatbergs that must be broken up and removed. At lift stations, they accumulate on screens and have to be removed, but if the bar screens are not narrow enough, they get into grinders and pumps and increase maintenance on those pieces of equipment. Wipes increase the maintenance that has to be performed on grinder pumps, dewatering pumps, mixers, and tanks.

An overloaded plant can also pose problems. If a clog has slowed wastewater from reaching your plant, you can have backups causing damage to homes and businesses. It may back up and enter the environment. If you have a sewer overflow, you face costly fines. When the wastewater finally releases as a clog is broken up and removed, you have a rush of wastewater coming into your plant. If you overload your equipment, you may have to release raw sewage, which can also lead to fines.

Wipes also drive up your plant’s disposal costs as items must be removed to containers, and trucked to landfills. You have the trucking fees, extra manpower, and disposal fees at the landfill.

The NACWA broke down what the added cost of wipes adds to a household’s sewer bill. In some areas, it’s about $5 a year, but it can be as much as $25 per year extra. This may not seem excessive, but added to other increasing expenses, it can strain households with a limited income.

There are two things you need to do. First, educate your district members about the importance of flushing only toilet paper and throwing out wipes, sanitary products, paper towels, condoms, etc. Make sure they are well aware of the problems that can drive up their annual wastewater bills. Second, install bar screens at your wastewater facility. Bar screens prevent a lot of frustration and damage in the long run.

What Do Bar Screens Do?

To reduce the damage and annoyance trash and wipes cause, bar screens are an important primary step in any wastewater treatment plan. If your plant doesn’t have a bar screen system or has an older, outdated one, it’s time to change that.

As wastewater comes into your plant, it travels through a channel and that channel has a series of coarse and fine bar screens that are usually spaced between a quarter-inch up to three inches apart. They trap items that shouldn’t be in a wastewater treatment plant, such as plastic or paper items that were flushed, animals that got into the sewers and died, and other debris like bone scraps that may get rinsed down the sink.

The bars trap the items, which could pose problems if they’re just left there. They’d block the flow of wastewater over time. That is prevented by having an automated rake that sits on the bottom of the channel and moves upward to capture all debris and some solids and lift it out of the wastewater.

At that point, the items that have been removed can go into bins to go to the landfill. Trash and hard organic materials aren’t going down the line where they can damage equipment or become extra work for your employees. The wastewater flows into the plant to begin the treatment process.

Choose a CO-TEC Screen for Easy Maintenance

The CO-TEC screens have fine and coarse galvanized steel or stainless steel bar screens that are cleaned by rake teeth that are positioned downstream of the bar screens to capture and remove trash and other debris. As all of the parts are above the surface of the wastewater, the maintenance on them is easier for your workers.

Lakeside Equipment is a trusted provider of wastewater bar screens and other crucial equipment that improves efficiency within your plant. New equipment does have an upfront cost, but the savings on the plant’s electricity bills provides a return on your investment in little time and keeps maintenance and operating costs down in the years to come. That makes the people in your district much happier in the long run.

Since 1928, Lakeside Equipment has specialized in water purification. Not only can we repair your existing wastewater treatment equipment, but our professionals offer sound advice on what you can do to improve your plant’s efficiency and avoid costly fees for improperly treated wastewater or sewer overflows.

Our team helps design the upgrades you request, keeping within your budgetary restraints, and installs bar screens that prevent problems caused by items that shouldn’t ever be flushed. Give us a call to find out more about the benefits of bar screens.

Sources:

https://www.mlive.com/news/2018/09/fatberg_metro_detroit.html