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Complete Water Services Article for the American Conifer Society

Complete Water Services Article for the American Conifer Society

“Water, water everywhere / Nor a drop to drink.” With only three percent of Earth’s water being freshwater, and only 12% of that as surface water, available groundwater, or other accessible water, that old saying from Samuel Taylor Coleridge’s poem The Rime of the Ancient Mariner speaks volumes.

“Civilization has been a permanent dialogue between human beings and water.” – Paolo Lugari

Harvesting rain is a practice that has been around for centuries. Cisterns and other rain harvesting systems are widely used in Europe, Africa, Australia, India, the Bahamas, and countless remote countries. Many individuals in these nations rely exclusively on rainfall for their day-to-day existence. Here in the United States, we, too, can successfully harvest rainwater to meet many of our needs.

When someone mentions rainwater harvesting (RWH), mental images of storage tanks, piping, hoses, etc., may come to mind. This is only one type of rainwater harvesting–active harvesting–and it works wonderfully well. However, there is another type called passive harvesting, which allows the soil to act as the “storage tank.” In this article, we will highlight both types of rainwater harvesting.

Value of RWH

The value of RWH cannot be overly emphasized. RWH can supplement potable (in some areas) and non-potable water demands, reduce run-off, reduce flooding, control erosion, manage stormwater quantity, increase water infiltration, reduce potable water costs, increase property values, and enhance environmental qualities.

Rainwater harvesting can be employed on a small or large scale, from a simple rain barrel, to an extensive multipurpose collection system. What is great about rainwater harvesting is that it does not need to be an elaborate or expensive proposition. It can be as simple as directing roof runoff to a swell or depression.

Types of RWH

The type of RWH you employ depends on the water needs, type of water usage, site location, amount of rainfall, drainage pattern, soil type, soil structure, etc. The following definitions are from the American Rainwater Catchment Systems Association (ARCSA)1:

Active Rainwater Harvesting: The collection and stor- age of rainwater in a container for later beneficial use.

Active Rainwater Harvesting System: The combined components that enable catchment, conveyance, removal, tank storage, and distribution of rainwater runoff for later beneficial use, including any needed pressurization and treatment.

Passive Rainwater Harvesting: The collection and infiltration of rainwa- ter into the ground for beneficial use, without intermediate storage in a tank.

Passive Rainwater Harvesting System: The combined components, including the passive infiltration structure, conveyance from rooftops, piping, rock, mulch, and other materials that enable the capture and infiltration of rainwater into the ground without intermediate storage in a tank.

Most RWH systems employ both types, an integrated system of active and passive rainwater harvesting. Needless to say, there are several ways to design an active RWH system. The possibilities are truly endless.

Basic Sizing of RWH

Calculate RWH Volume: A general rule-of-thumb is that you can harvest around 620 gallons of rainwater during a 1″ rain event per 1,000 square feet of roof area. Many calculators are online to assist with calculating the volume of rainwater available in your area.2
Determine Monthly Water Demand: With the end use(s) in mind, estimate the total amount of water that you will use for each month of the year. You can find several charts on the Internet to help estimate the water required per use/per person/per area,2 etc.; however, the demand will be based on your particular needs.

Passive RWH

Passive RWH is the most common way of using harvested rainwater. It can be the simplest and easiest way, too, because systems can be installed without pumps and the end use usually does not require in- tense treatment. The axiom for passive RWH is:


Slowing the flow of rainwater makes it easier to manage and reduces detrimental effects, such as erosion. Routing the flow in the desired direction provides an opportunity for filtering, infiltration, and conveyance to areas of use. Growing means guiding the water directly to the root zones of the plants to reduce water usage and evaporative losses and then letting nature handle the rest.

Passive RWH structures can be constructed in count- less shapes, sizes, and configurations to accommodate the lay of the site and to intercept the flow from rooftops, hardscapes, impervious surfaces, land- scapes, and slopes. Passive structures can retain a significant amount of rainwater and come in many types:

  • A basin, with or without berms or multiple basins Waffle gardens: sunken garden beds that look similar to the indentations in waffles
  • Rain gardens: amended beds for increased wa- ter-holding capacity
  • Contour swales, with or without berms
  • Contour swales inside larger drainage basins
  • Wattle swales: long sausage-shaped products, often filled with straw, used to slow the flow rate and detain debris and sediment
  • French drains: underground structures (e.g., rock- filled trenches or corrugated drainage piping) so that water can drain and infiltrate adjacent soils Rain barrels
  • Curb cuts to help disperse water from impervious areas
  • Permeable paving and porous concrete

Most passive RWH structures are hidden behind a cover of plants and disappear from view but continue working nonetheless.

General Approaches to Passive RWH

Site-specific factors for passive RWH sizing and design include

  1. Goals for the site such as controlling erosion, supporting vegetation and plantings, and reducing runoff
  2. The amount of water needed by new and existing plantings
  3. The size of available catchment areas
  4. Local rainfall averages and maximums
  5. Runoff coefficients for the different catchment surfaces (charts and calculators are available on many websites3)
  6. Infiltration rates based on site-specific soil types and conditions
  7. Depth of usable soils above non-infiltration zones such as hardpan, clay lenses, high groundwater table, bedrock, etc.
  8. The lay of the land in relation to how and where the flow will be routed
  9. Local regulations on the maximum depth of impounded water

Strategies for a Passive RWH System

Effective strategies for a passive RWH system that focus on efficient rainwater utilization and landscaping practices include

  1. Leave as many native trees or plants as possible and work these into the overall RWH plan
  2. Remove vegetation and reshape the topography to direct roof and surface runoff to the new infiltration areas constructed
  3. Meet outdoor water demand for existing and new plants using passive RWH to the greatest extent possible or practical
  4. Replace grass or other high-water-demand vegetation with native, low-water-use and low-maintenance trees and shrubs to provide shade, cooling, food, and wildlife habitat
  5. Be cognizant of sun angles, which vary with latitude, when planting trees and shrubs. These can be placed to allow the low angle of the sun to warm buildings during cold months while shading buildings during the warm months
  6. Place new planting areas adjacent to or near hardscape areas that can provide runoff watering
  7. Calculate basin volumes and dimensions (or other containment structures) based on direct rainfall plus the runoff that will flow into them
  8. Construct overflow structures to direct and convey excess water from passive RWH areas to other areas for beneficial use

Rain Barrels

Rain barrels are one of the easiest and most inexpensive ways to collect rainwater for future use. From utilitarian to highly decorative, rain barrels come in various colors, sizes, and styles so that they can be incorporat- ed seamlessly into your landscape.4

When selecting a rain barrel, there are various factors to consider. Volumes of barrels vary from 35 gallons to 120 gallons. Many have interconnecting nozzles on the sides so that barrels can be manifolded together. Most are made from heavy-duty plastic, providing UV protection and making them durable. Barrels should have a screen across the inlet to keep out debris and insects, particularly mosquitoes. Barrels should have an overflow nozzle at the top and a spigot (or another type of outlet) at the bottom. Ensure the spigot is high enough if a watering can is to be placed underneath. The barrel may need to be placed on a stand.

Active RWH

Active RWH systems have become increasingly relevant as populations and water demands have drastically increased. Shortages of conventional water supplies, extended droughts, and groundwater and surface water depletion are just some of the current and future challenges. Even in the most arid climates, there is sufficient rainfall for active RWH to help meet a wide range of water requirements.

Active systems can utilize everything from small barrels to large, interconnected tanks; from underground collection systems to lined ponds. Active systems provide many benefits:

  • Maximize the use of free, local rainfall
  • Reduce demands from potable, surface water, and water well sources
  • Provide stored water for use during drought and use restrictions
  • Provide safe potable water when no other source is available
  • Supply water during peak demand periods
  • Provide water for firefighting and other non-potable uses

Active RWH systems must safely capture, collect, convey, filter debris, store, pump, and treat (filtration, disinfection, etc.) rainwater for the intended quantity, quality, and use. Components include

  • Catchment surfaces (e.g., roofs, parking lots, im- pervious surfaces)
  • First flush diverter
  • Conveyance to tank or other storage element
  • Debris filtering and removal
  • Storage vessel or system (barrels, totes, tanks, cisterns, ponds, etc.)
  • Piping to and from storage vessel or system
  • Pumps and pressurization systems (if required)
  • Post-storage filtration and disinfection (if required by end use)
  • Irrigation system (if required by end use)

General Approaches to Active RWH

To optimize the effectiveness of an Active RWH system, consider the following general approaches:

  1. Ensure that the gutters, downspouts, and inflow pipes are sized sufficiently to handle the maximum amount of rainfall
  2. Ensure that the tank overflow piping has a capacity equal to, or preferably larger, than the inflow piping
  3. Ensure overflow from underground tanks has a safe point of discharge, preferably for beneficial use
  4. Direct any overflow to a location for beneficial use
  5. Design the system to yield high-quality water. Be cautious of toxic materials, such as harvesting from areas that have pesticides and herbicides applied, vehicle drippings, chemical storage areas, railroad ties, landscape timbers, etc.
  6. Use components rated for use in potable water systems if the rainwater is to be used as drinkable water or may be used as such in the future
  7. Use calming influent devices to minimize sediment disturbance at the bottom of the tank, for example, install outflow piping four inches or more above the bottom of the tank, or use a floating outflow device to minimize sediment disturbance
  8. Block sunlight to prevent algae growth
  9. Install screens on all ports to eliminate insects, birds, and vermin
  10. Install self-cleaning or minimal maintenance pre-filters to enhance water quality. Locate these in easy-access locations
  11. Install first-flush devices in low-maintenance locations
  12. Maintain access around tanks (rule-of-thumb is three feet) and inside tanks for inspection, cleaning, and repair
  13. Secure tanks with lockable lids for safety and to prevent unwanted entry
  14. Vent tanks to allow airflow for changing water levels to keep the tank from collapsing
  15. Use gravity flow where feasible for energy-free water delivery

Strategies for an Active RWH System

To optimize the functionality of an Active RWH System, consider implementing the following strategic measures:

  • Select a tank location that is appropriate for the catchment surface and is in the proximity of the end use
  • Determine the type of conveyance based on the site climate: dry conveyance (where the convey- ance system is designed to drain all the rainwater directly into the tank and remain dry between rainfall events) can be used in hot or cold climate areas and wet conveyance (where the conveyance system is designed to hold standing water between rain events) is susceptible to freezing in colder climates
  • Select a storage tank with dimensions based on the specific site constraints, required capacity, catchment surface height (e.g., roof overhang height), prefiltration devices, tank materials, etc.
  • Select a water treatment system regime based on the quality of water required by the end use
  • If used to supplement potable water, ensure that the required backflow prevention devices are in- stalled per the local code


Please be aware that the legal right to harvest and use rainwater varies depending on state and local laws, regulations, practices, and codes5. This variation arises from the complexities of water rights and allocations. It is essential to consult with your state and local agencies to understand the specific regulations and requirements that apply to rainwater harvesting in your area6. Additionally, it is advisable to investigate any relevant planning, building, and installation codes and regulations before initiating any rainwater harvesting projects to ensure compliance.

It has never been more important to work for environmental sustainability. Rainwater harvesting systems provide distributed stormwater runoff containment while simultaneously storing water that can be used for irrigation, landscaping, flushing toilets, washing clothes, washing cars, and pressure washing, or it can be purified for use as everyday drinking water. Harvested rainwater has many diverse uses, but its impact is the same-water conservation.

Active and passive RWH tactics, whether used separately or together in a comprehensive plan, can turn stormwater problems into water supply assets. From large-scale projects or a single rain barrel, RWH practices can supplement or entirely supply high-quality water now and into the future.

Small steps can make a huge impact.

“If there is magic on this planet, it is contained in water.” – Loran Eiseley

Further Reading

  1. American Rainwater Catchment Systems Asso- ciation (ARCSA), Rainwater Harvesting Manual, 1st Edition Second Printing, 2015.
  2. Example of Comprehensive Calculators: Depart- ment of Energy, Texas A&M Agrilife Extension,
  3. MyMathTables Rainwater Runoff Calculator, https://www.mymath weather/rainwater-runoff-using-rational method.html. Runoff Coefficient Fact Sheet
  4. The Spruce. The 9 Best Rain Barrels of 2023.
  5. Federal Energy Management Program, Rainwa- ter Harvesting Regulations Map,; Pacific Northwest National Laboratory, Rainwater Harvesting State Regulations and Technical Resources, PNNL-24347 Rev 1, June 2019. publications/external/technical_reports/PNNL-24347Rev.1.pdf

Top Three Things to Do If You Receive A Notice of Violation for Your Industrial Wastewater Pretreatment System

  1. Do not ignore the violation letter
  2. You need to develop a response to the permitting authority as soon as possible, the violation letter will often include a timeline as to when response should be submitted. Facilities that have a series of violation letters may be categorized a significant violator, this may include fines as well as having the facility listed a significant violator in the newspaper and other publications.

  3. Investigate the cause of the violation
  4. It can be difficult to determine the cause of a violation as sometimes they may have occurred several weeks before a lab analysis is received that notes the violation or a violation letter is issued.
    Some common causes may include-

    • Operating pH is out of spec-proper pH is critical to many physical/chemical treatment processes as well as biological treatment processes. In addition, permits include a range of pH levels that discharge pH must be within to avoid violations
    • Treatment equipment may need cleaning-some processes will carry over solids into the effluent if not properly cleaned periodically.
    • A higher than normal discharge of untreated wastewater may have been sent to wastewater treatment, this happens on frequent basis in food processing plants and may be hard to confirm weeks after it occurred, especially if no one reported unusual conditions. You need to have good communication with production and sanitation personnel that are aware that high strength discharges can have a significant impact on wastewater treatment processes and are willing to notify wastewater operations if this occurs. It is important for pretreatment system operators to recognize potential problems with high influent loading conditions and document when it happened and possible corrective actions that may be required.
  5. Develop a response to the violation letter
  6. Violation notices require a response within a specified time with a corrective action plan that will prevent future violations. The corrective actions listed must be realistic and hopefully capable if being implemented quickly. If the corrective action will take some time to be implemented, this should be negotiated with the permitting authority.

    CWS can provide audits of food manufacturing facilities with a report on deficiencies along with recommendations on options for corrective actions. Our clients tell us they appreciate our many years of experience and that we advise them on the most cost-effective but reliable solutions to their issues.

Jim Lewis Celebrated for Dedication to the Field of Water Treatment Services


Jim Lewis Celebrated for Dedication to the Field of Water Treatment Services
Jim Lewis Celebrated for Dedication to the Field of Water Treatment Services

Mr. Lewis channels decades of business expertise into his work with Complete Water Services, LLC

MARIETTA, GA, October 28, 2020, Jim Lewis has been included in Marquis Who’s Who. As in all Marquis Who’s Who biographical volumes, individuals profiled are selected on the basis of current reference value. Factors such as position, noteworthy accomplishments, visibility, and prominence in a field are all taken into account during the selection process.

Drawing upon years of expertise in environmental awareness, wastewater treatment, business development and environmental engineering, Mr. Lewis excels as president of Complete Water Services LLC, which provides commercial, community and industrial water solutions alongside various other professionals, including engineers and certified water operators. Prior to joining Complete Water Services, he honed his expertise in the field as vice president of Superior Water Service between 1983 and 2001.

Although his career has been filled with highlights, Mr. Lewis is especially proud of entering the field around the same time that the Clean Water Act was passed during the early 1970s. After witnessing the country make an effort to clean up our water, he was inspired to further the work of those who came before him. Over the years, he has also been honored to work with industry experts and his company has won several awards for their work, including multiple Industrial Treatment Plant of the Year awards.

Driven to remain aware of ongoing changes in the field, Mr. Lewis aligns himself with the Georgia Association of Water Professionals, the International Association of Corrosion Engineers, the American Rainwater Catchment Systems Association, and various water treatment and technology associations. In the near future, he intends to continue his work on the growth and success of CWS.

About Marquis Who’s Who®:

Since 1899, when A. N. Marquis printed the First Edition of Who’s Who in America®, Marquis Who’s Who® has chronicled the lives of the most accomplished individuals and innovators from every significant field of endeavor, including politics, business, medicine, law, education, art, religion and entertainment. Today, Who’s Who in America® remains an essential biographical source for thousands of researchers, journalists, librarians and executive search firms around the world. Marquis® publications may be visited at the official Marquis Who’s Who® website at

Wastewater Treatment for the Industrial Metal Finishing Industry


Published by Finishing and Coating, 23 October 2020

The wave of globalization in manufacturing has led to new manufacturing processes being implemented in locales that do not have previous experience with industrial wastewater discharges, much less with the impacts that the contaminants, which may be present in these discharges, have on human health and the environment.

Jim Lewis

Metal finishing is a prime example of the type of industry that has expanded on a worldwide basis. This article details the impacts that metal finishing operations may have on the local water supplies and the types of treatment systems options available to make these discharges safe for the environment.

Metal finishing industries cover a broad range of processes including electroplating, electroless plating, anodizing, coatings, etching and chemical milling, and printed circuit board manufacturing. Contaminants and characteristics of wastewater from these types of operations include:

  • pH excursions caused by acid and caustic cleaning, and plating bath carryover
  • High levels of heavy metals used in plating operations
  • High levels of phosphorus resulting from phosphate coating operations
  • High levels of cyanide (cyanides are used to improve the plating process)
  • High levels of toxic organic compounds that are associated with oily wastewater and solvents used for cleaning, etc.

Even though metal finishing processes may be the same type, wastewater from an individual facility is unique to that specific facility. Each of the contaminants or characteristics stated above has a treatment process, which when combined, results in a treatment train that is designed specifically for that particular wastewater.


Equalization (EQ) is a means of buffering or equalizing the characteristics of wastewater prior to entering the wastewater treatment system. Industrial waste streams vary considerably in both level of contaminants (pH, total suspended solids, etc.) and flow rates. To minimize the impact of these fluctuations on downstream processes, equalization should be considered. Benefits of EQ include:

  • Substantially reduced chemical costs, especially associated with pH fluctuations, and coagulants and flocculants required for solids removal.
  • Smaller downstream treatment components. Downstream treatment components do not have to be sized to handle instantaneous flow peaks.
  • Ease of operations. EQ substantially reduces process adjustments required in day-to-day operations.
Belt Press

Most EQ systems consist of a tank that is mixed or aerated to keep solids from settling to the bottom. Depending on the waste stream, aeration may be required to keep the waste from becoming odorous or assist in oxidizing some metals. A good Rule-of-Thumb for EQ systems is to be capable of holding one day of peak wastewater flow. If the waste stream has large settleable solids, screening may be required prior to equalization. Also, considerations must be made with regard to the type of coating on the tank, especially if the waste stream is very acidic or basic.

Neutralization and pH Adjustment

pH is a measure of the degree of acidity and basicity of a solution. More exactly, it is the measurement (negative logarithm) of the hydrogen ion concentration [H+]. The scale ranges from 0 (most acidic) to 14 (most basic). The term pH refers to “pondus hydrogenii” or power of hydrogen.

Because pH is simply another means of referring to the hydrogen ion concentration, acidic and basic solutions can be distinguished on the basis of pH values:

pH < 7 Acidic solution pH = 7 Neutral solution pH > 7 Basic solution

DAF Unit

Neutralization of wastewater that is highly acidic (low pH) or highly basic (high pH) is required for discharge to municipal sewer systems or to rivers and streams. The most common allowable pH range for discharge is generally 6 to 9 standard units (S.U.) but can be 5.0 to 11.0 depending on the source of discharge. There are four main reasons to control the pH in wastewater:

  • Protect human health and the environment; fish and other living organisms in rivers and streams.
  • Protect the wastewater infrastructure from corrosion, especially from acidic wastewater.
  • Protect the biological treatment process incorporated at most municipal treatment systems.
  • Many pretreatment processes require that the pH be adjusted as an initial step in treatment so that the processes work correctly, such as:
    • Coagulation and flocculation processes for the removal of oil and grease, phosphates, and suspended solids.
    • Precipitation of metals in the metals removal treatment processes.

Wastewater with a low pH is generally neutralized using sodium hydroxide (NaOH), lime (CaO), magnesium hydroxide (Mg(OH)2), or calcium hydroxide (Ca(OH)2). Wastewater with a high pH is generally neutralized with sulfuric acid (H2SO4), hydrochloric acid (HCl), or carbon dioxide (CO2). The most common chemicals used are H2SO4 and NaOH.

Neutralization can be accomplished by batch treatment or continuous flow processes. Batch treatment is usually for lower flow volumes.

Most systems are continuous flow type systems consisting of one or two neutralization tanks, depending on the flow rate and magnitude of pH swings. With some systems, the pH must be raised or lowered for other removal processes to function properly, and then the pH adjusted back prior to discharge.

Chrome Reduction

Hexavalent chromium (Cr6+) is a form of chromium that is toxic to humans and to the microorganisms in biological treatment plants (i.e. municipal sewage plants). It cannot be precipitated by conventional treatment processes; therefore, it must be converted (reduced) to the less toxic form of trivalent chromium (Cr3+). Trivalent chromium can then be precipitated as chromium hydroxide.

EQ Glass Lined Tanks

Hexavalent chromium is typically reduced with sodium bisulfite (NaHSO3) at a pH range of 2 to 3 SU using sulfuric acid, with the Oxidation Reduction Potential (ORP) at +250mV or lower. The pH and ORP must be maintained at least for 45 minutes for the reaction to occur. It takes three parts of sodium bisulfite and one part sulfuric acid to one part chromium.

Once the reduction has occurred, the pH should then be raised to 7.5 to 8.5 SU which is the optimum range for the trivalent chromium to precipitate. This conventional chromium reduction treatment process is capable of producing an effluent with less than 0.1 milligram per liter (mg/L) of hexavalent chromium.

Cyanide Destruction

The destruction of cyanide is normally a 2-step process known as alkaline chlorination. Basically, sodium hypochlorite (NaOCl) and caustic (NaOH) are used to break the cyanide bond under alkaline (basic) conditions by first oxidizing cyanide to cyanogen chloride and then to cyanate. The second stage in cyanide destruction is to oxidize the cyanate to carbon dioxide and nitrogen gas.

Stage 1 is the destruction of cyanide that is amenable to chlorination. It is accomplished by the addition of sodium hypochlorite and caustic to raise the pH to 10.5 SU and the ORP to a minimum of 500 mV.

In this stage, the oxidizing agent, sodium hypochlorite, causes the oxidation of cyanide (CN–) to cyanogen chloride (CNCl) and then further oxidized to cyanate (CNO–). The reaction time can be up to 60 minutes during which the conditions of pH at 10.5 SU and ORP ≥ 500mV must be maintained.

pH Adjustment

In Stage 2, acid is added to lower the pH to 8.5 SU so that the cyanate would oxidize. Lowering the pH allows more chlorine (of the hypochlorite that was added under Stage 1) to be released and the ORP increases. Usually, no additional hypochlorite is required.

The ORP must be maintained above 800 mV and the pH around 8.5 for 30 to 60 minutes for this reaction to occur. In some instances, this reaction can take up to 120 minutes. It takes 7.5 and 8 parts of sodium hypochlorite and sodium hydroxide, respectively, per part of cyanide to perform the oxidization of cyanide.

Destruction of cyanide is very reliable using this method if the system is well maintained. Most problems with this treatment system occur with ill-maintained ORP control systems. Failure of the ORP control is the single largest culprit of treatment system malfunction.

Chelated Metals Treatment

Plate and Frame Press

Chelating agents are widely used in industrial applications. Chelates (from the Greek word chela meaning “claw”) complex with metals, thus tying them up and keeping them in solution. This sequestering effect makes chelating agents widely used in cleaning formulations for their ability to dissolve and remove rust, scales, and other debris from metal surfaces. Metal chelates form over a wide range of pH, are highly soluble, and extremely stable.

Some of the most common chelating agents are ethylenediaminetetraacetic acid (EDTA), citrates, nitrilotriacetic acid (NTA), and hydroxyethylenediamine triacetic acid (HEDTA). These compounds form 1:1 complexes with many metal ions, the most common being cadmium (Cd), copper (Cu), lead (Pb), nickel (Ni), zinc (Zn), and mercury (Hg).

Because these compounds are highly soluble and stable, treating wastewater with these complexes can be challenging. In general, the more effective the chelating agent is, the more difficult the metal is to remove. There are generally two methods to remove chelated complexes:

  • Removal by ion exchange, nano-filtration or reverse osmosis. These technologies generate concentrates that have to be further treated before properly disposed.
  • Breaking the chelate complex is treatment. This is done by either low pH or high pH combined with sulfide technology. These treatment technologies break the complex bonds and free the metal ion for further treatment by precipitation, etc.


Sludge Conveyor

Clarification (used interchangeably with settling and sedimentation) is the separation of suspended solids from water or wastewater using gravity. Suspended solids include settleable and colloidal solids. Colloidal solids must be chemically treated by the processes of coagulation and flocculation to enhance removal by settling.

The process usually incorporates a rectangular or circular tank (clarifier) that holds the water or wastewater during a set period of time to allow the solids to settle to the bottom. Most clarifiers have a cone or sloped bottom section that concentrates the settled solids. The solids can then be pumped to storage or further treatment.

Some systems include a surface skimmer to remove materials that float and a bottom skimmer to push the sludge to a sludge hopper. These type systems are more common in municipal water and wastewater applications.

Clarifiers used in many industrial applications are rectangular and include inclined plate packs that enhance settling. These plates are usually set at an angle of 45 to 60 degrees. Inclined plate clarifiers work very well for metal finishing wastewater. Wastewater with heavy oils and grease or other viscous materials are not well suited for inclined plate clarifiers as they tend to clog the units. Most inclined plate clarifiers include integral mixing chambers for chemically-enhanced settling.

Dissolved Air Flotation

DAF systems are designed to remove suspended solids along with fat, oils and grease (FOG) from a waste stream by flotation, as opposed to gravity separation. DAF systems work exceptionally well in waste streams that include solids that tend to remain in suspension or float such as chemical and petroleum-based waste streams.

Prior to the DAF, the wastewater must be chemically treated by pH adjustment, coagulation, and flocculation. DAF systems are designed to remove the solid particles formed by the coagulation and flocculation processes by using very small air bubbles that attach to the flocculated particles causing them to float to the surface for removal by skimming. Many DAF systems incorporate a serpentine pipe flocculator for mixing and dosing coagulants and flocculants instead of conventional tanks and mixers.

The tiny bubbles are formed by injecting air under pressure into a wastewater recirculation stream. This recirculation loop uses 10% to 30% of the discharge from the DAF. This air-saturated recirculation stream is returned back to the influent of the DAF for mixing with the incoming, untreated wastewater. When the pressurized water is suddenly released to atmospheric pressure, the air comes out of solution and creates very fine air bubbles (whitewater) that attach and enmesh to the solid particles causing them to float.

DAF systems are equipped with a skimmer for removing the “float” into a sludge hopper. The float is then transferred to the solids handling system for further processing.


Filtration is a physical or mechanical operation which separates solids from fluids with the help of a medium called a filter. When the solution is brought in contact with the filter medium, the filter allows the fluid to pass through but retains, at least part, of the solid material. The fluid that passes through the filter is called the filtrate, while the solid material that remains on the filter is called the residue.

There are two main types of filter media: 1) Solid sieve-like media such as filter paper that traps the solid particles; 2) Bed of granular material, like sand, that retains the solid particles as the fluid passes through. The first type of media allows the residue to be recovered intact while the second does not.

Multi-media filtration is a significant improvement over single-media filtration systems such as sand filters. In a conventional sand filter, lighter and finer sand particles are found at the top of the filter bed, and coarser, heavier sand particles remain at the bottom after backwashing. Filtration takes place in the top few inches of the filter bed. For multi-media filters, the coarse media traps large particles and successively smaller particles are trapped in the finer layers of media deeper within the bed. Multi-media filtration permits delivery of high quality filtered water at much faster flow rates, as compared to a conventional sand filter.

Multi-media filters have a granular gravel support bed and the filter media is a natural zeolite. Zeolites are microporous, aluminosilicate minerals commonly used as filter media and commercial adsorbents. Zeolites filter by traditional particle mechanisms like the sand filters and also by their cage-like pore structure. Zeolites are the aluminosilicate members [(AlO2)6(SiO2)30-624H2O] of the family of microporous solids known as “molecular sieves.” The term molecular sieve refers to a particular property of these materials, i.e., the ability to selectively sort molecules based primarily on a size exclusion process. This is due to the molecular dimensions of very regular pore structure. The maximum size of the molecular or ionic species that can enter the pores of a zeolite is controlled by the dimensions of the channels.


Membrane technologies represent the cutting edge of filter-based purification technologies. Membranes are used in a wide variety of applications including desalinization, high purity systems and many types of wastewater applications such as membrane bioreactors, oil removal, sulfates and metals removal, and dissolved solids removal, etc.

Common membrane applications include ultrafilters to remove suspended solids and oils (as well as in MBRs); nano filters, to remove suspended solids and some large-molecular-weight dissolved contaminants; and reverse osmosis, for high-purity applications, desalinization and wastewater reuse (dissolved solids).

Membrane systems are available for a variety of flow applications and system sizes; however, in wastewater, many times membranes are applied inappropriately.

The simple principle of a membrane is that it acts as a very specific filter that will let water flow through while suspended solids and other substances are retained. There are two factors that determine the effectiveness of a membrane filtration process: selectivity and productivity. Selectivity is expressed as a parameter called retention or separation factor. Productivity is expressed as a parameter called flux. Selectivity and productivity are membrane-dependent.


Precipitation is the formation of a solid in a solution through a chemical reaction that forms an insoluble compound out of two or more soluble compounds. Precipitation is also the act of separating a solid from a solution. The solid that is formed is called the precipitate, and the liquid solution is called the supernate.

Precipitation is not to be confused with coagulation, although many in the industry use these terms interchangeably. Precipitation is the formation of a solid. Coagulation is the agglomeration of the solid particles.

In most situations, the solid that forms settles out of the solute phase, and settles to the bottom of the solution (though it will float if it is less dense than the solvent or form a suspension). The solid may reach the bottom of a container by means of settling or sedimentation. The separation can be accomplished in a clarifier or settling basin. Floating solids can be removed by enhancing the flotation characteristics and using a DAF unit. Precipitation is a very common process in metals removal.

Solids Handling

The coagulation and flocculation processes chemically convert colloidal solids into larger solids for separation by settling or flotation. This generates an industrial sludge that will require proper handling.

Sludge coming from the processes listed above will be primarily comprised of water. It can be expensive to dispose of wet sludge by weight. To address this, there are several ways to dewater sludge. Two common ways are decanting and pressing.

Sludge dewatering by decanting is the sample principles as discussed above. When the sludge sits in a holding tank, the water rises to the top, is drained off, and it is put back into the treatment system at the head of the works.

A sludge dewatering press, as the name implies, physically squeezes the water phase from the solids phase. This can be done by several methods such as belts and rollers, cloths and plates, screws, etc. A rotary press uses centrifugal force instead of squeezing force to separate the water from the solids. Each of these press types has its proper application.

However, for metal finishing sludges, plate and frame presses are the most common. The plate and frame press is actually a filter that incorporates several individual plates that have porous cloths for filtering the sludge from the water. Sludge is pumped from a holding tank to the press where the water phase passes through the filter cloths while retaining the solids on the cloth within each plate chamber. A hydraulic system is used to press the plates together. When the press is opened, the solids fall into a receptacle for proper disposal.

Implementing proper pretreatment processes will ensure that industrial metal finishing waste streams contribute minimum impact on human health and the local environment in these new and emerging markets.

Jim L. Lewis is President of Complete Water Services, LLC. Call 678-355-9270, visit or email him at The author would like to thank Karen J. Niebuhr, PE, Complete Water Services, LLC, for her assistance with this article.

Food Manufacturers: Top 3 Wastewater Troubleshooting Tips

Food Manufacturers: Top 3 Wastewater Troubleshooting Tips

Did you know that many food manufacturers have 3 issues in common when it comes to meeting wastewater discharge permit requirements? They include pH, total suspended solids (TSS) and fats, oil and grease (FOG). The most common processes for treating these constituents is pH adjustment, and chemically assisted dissolved air flotation (DAF) for TSS and FOG removal.

The following troubleshooting tips are offered to assist the treatment plant operator with common operational problems with these processes. Complete Water Services LLC has the knowledge and experience for correcting operational problems of existing systems, or for providing a turnkey approach for installing new or replacement systems. Below are 3 simple troubleshooting tips to keep your wastewater treatment system operational.

  1. Effluent Wastewater pH Outside Permit Conditions
  2. Maintaining proper pH is the #1 problem with most food plant wastewater discharges. For example, if the pH is too low or too high it may be out of range for the plant discharge permit. Unfortunately, this can cause a permit violation. In addition, proper pH levels are critical to separation chemistry for removing FOG and TSS. For example, if pH of the wastewater in the DAF or clarifier systems are too low or too high, the treatment chemicals will not work properly. This can cause increases in effluent contaminants and result in permit violations. Therefore, take these three steps:

    • The first thing you want to do is clean and calibrate the probe on a routine basis. Clearly this sounds simple, but oftentimes the probe is not reading the pH correctly due to a buildup of solids or grease. Therefore, routine cleaning of the probe often corrects the pH problems. In addition, we also strongly recommend keeping a backup pH probe in inventory. This could be a wastewater life saver because it could take days to get a new one if it goes out. Further, we also recommend providing the wastewater operators with a hand held pH meter so they can confirm the system controller is working properly. However, if you are experiencing pH violations and do not have an existing pH control system, CWS can provide a turnkey solution for you.
    • The second thing to look into is the size of the chemical metering pump. Oftentimes they are too small to provide enough chemical to correct the pH properly. Interestingly, the wastewater chemicals used to correct pH in the wastewater need to be dosed within a specified time. However, if the pump is too small it will not deliver the required amount of chemicals, within the required time, to properly adjust the pH. In addition, you should also confirm the pump has not lost prime if you are experiencing pH issues. Unfortunately, this occurs more than one would think.
    • Last, you will want to make sure the pH adjustment process has adequate mixing, or retention time, to allow the wastewater to actually reach the desired pH level.
  3. High Suspended Solids in the Effluent in Excess of Permit Conditions
  4. A variety of issues can cause high TSS in the effluent. However, one of the most common causes are when there is too much flow through the separation process. For example, when the DAF (or clarifier) is rated for 100 gallons per minute, but you are pumping 200 gallons per minute, it will result in much higher effluent solid numbers. Too high of flow rate can exceed the time required for the separation process.
    Another problem that can cause solids carryover is improper treatment chemistry. Jar tests are a good way to evaluate this type of problem.
    Another cause is when the wastewater separation process has excessive settled solids buildup in the unit. To prevent this, most DAF manufacturers recommend washing out the DAF once per week. Unfortunately, if the sludge settles and accumulates, the DAF or clarifier will “blow solids” because it is not being emptied properly.

  5. High Fats, Oil and Grease in the Effluent Discharge
  6. High oil and grease in the effluent is common to most food processing plants, whether you are making bread or brisket. However, the oil and grease may come from butter in the baking process, or fats from processing meat protein products, but it shows up as FOG in the effluent.

    However, you may be able to correct this by tweaking the chemistry in the solid’s separation process. In addition, you could also correct some of the issues noted previously, such as correct pH or flow problems.

    When in Doubt Call Complete Water Services for Wastewater Troubleshooting
    CWS is a team of professionals with extensive experience solving industrial, commercial and community water supply and wastewater treatment challenges. Most importantly, CWS offers a powerful combination of hands-on plant experience, design, consulting, troubleshooting, and construction expertise.

    If you are in need of a wastewater system audits, CWS can help. In addition, we can produce a report that defines the causes of discharge permit problems. Further, our experts can help you budget for wastewater system upgrades or wastewater operator training. Please contact us with any questions or to schedule a site visit.

VoyageATL features Jim Lewis of Complete Water Services

Jim Lewis

VoyageATL features Jim Lewis of Complete Water Services

Meet Jim Lewis of Complete Water Services in Marietta

Today we’d like to introduce you to Jim Lewis.

Jim, can you briefly walk us through your story – how you started and how you got to where you are today.

I started out as a water system operator working at night while I went to college during the day. I worked my way up to supervisor with the City of Atlanta water system. I switched to industrial water treatment, co-founded a water treatment company in Atlanta.

I joined CWS in 2000 as President, We have been involved in providing treatment systems for North and South America and I have had the opportunity to travel the world for my work. I have been fortunate to begin working in water treatment when the Clean Water Act and EPA were initially founded and to observe the improvement in water quality in the US and Atlanta through the years.

We in the US take for granted how safe our water is (we still have problems and work to d0) but the US is far ahead of most countries. It has also been fascinating to see how water is used in processing food, cars and many things we use every day. I have been lucky to have knowledgeable, kind mentors, collaborative partners and smart, capable teammates. I am still passionate about water as much as when I started.

Great, so let’s dig a little deeper into the story – has it been an easy path overall and if not, what were the challenges you’ve had to overcome?

Not always, It can sometimes be difficult working in foreign countries. Also, we are considered a small company but we often compete against the largest water treatment companies in the world (we win a significant number of these projects even competing against the big guys).

In addition, we are sometimes asked to help clients clean up water that is loaded with hard to treat contaminants to levels that are barely detectable with testing. Travel can be tiring as well.

Complete Water Services – what should we know? What do you guys do best? What sets you apart from the competition?
Our company offers design/build treatment systems primarily for industrial factories that use water for processing their products. This includes food, beverage, automotive, chemical and metal finishing, we also provide water treatment for oilfield systems. This means we design the treatment process, construct it and frequently provide operations staff for our clients.

CWS has been involved in almost every facet of water use-water supply (we developed an abandoned rock quarry as an emergency water supply for a GA county), bottled water production in Hawaii, water supply and wastewater treatment for a youth camp in N GA, oil field treatment in Northern Canada, aluminum production treatment in Patagonia region of Argentina and the water fountains in Centennial Park for the Olympics in Atlanta.

We provided a system to recycle seawater for Mote Marine in Sarasota, FL for a study they were doing on crude oil spill effects on fish life cycles in the Gulf. These are just a few examples of the projects we have been involved in. I believe we offer an amazing level of expertise for a small company and we are devoted to helping our clients stay in compliance with environmental regulations and providing a safe water supply.

What moment in your career do you look back most fondly on?
When a system our company designed and built won the state of GA water professionals award for treatment plant of the year.