Advanced Wastewater Treatment

Biological Sewer Sludge Treatment and Reduction

Aqua Tech’s biological process carries out complete sewer sludge treatment eliminating the need for a clarifier.

This sewer sludge treatment is based on biofilm technology. Biofilm is a dense community of attached-growth microorganisms living on specially designed plastic media. Having direct contact with wastewater, biofilm absorbs and oxidizes pollutants thus providing treatment. Multiple biozones ensure that an appropriate biological system develops according to the nature of wastewater composition. It supports dynamic balance on its own both in mass and qualitative composition according to variations of wastewater parameters (within the range of optimal adaptation rates and allowable values of design loadings).

depiction of three layer biofilm on plastic media

Multi-Chamber Design

Multiple chambers in our bioreactor create a series of ecosystems in which the excess biomass is digested and mineralized in successive chambers by higher level microorganisms. This process converts organic sludge into carbon dioxide, water and inorganic elements.

Each chamber houses specialized media to host the required microorganisms.

Specialized Bio-Film Media

floating media for wastewater biofilm

The first chamber of the bioreactor houses a smooth-surface floating media. The smooth surface coupled with high turbulence in the first chamber prevents high biofilm accumulation on the media.

Sloughed biofilm travels into the next chamber to be consumed by protozoa inhabiting porous media (Bio-Chip).

Floating media for biological film wastewater treatment plant

The Bio-Chip media mitigates biofilm overgrowth as the chips rub against each other under aeration. These unfavorable conditions on the outside of the Bio-Chip cause microorganisms to inhabit primarily the protected interior of the media. Treatment in this chamber is provided by slow-growing bacteria such as ANAMMOX which produce negligible biomass.

wastewater treatment biological reactor static media

Subsequent chambers facilitate the development of a complete trophic system with all four trophic levels. This means that the amount of bacteria are controlled by Protozoa and Metazoans that consume any surplus bacterial biomass.

The last chamber utilizes static media and minimal aeration intensity to ensuring high efficiency adsorption and mineralization of any residual suspended matter.

Nota Bene:

The above described is the conceptual model or ideology of the bioreactors which does not change if a bioreactor has just two or three chambers. Thus, any our biological process is designed so that effluent biomass amount is within the required effluent limit for TSS.

Wastewater systems in the US are sized based on the maximum number of gallons per day they can treat.

A 300-room hotel, for instance, might require a 50,000 gallon-per-day system. Depending on soil loading rate*, that system might need a 2 acre drip field for effluent disposal.

An installer walking inside a wastewater system drip field dosing tank.
Every component in our systems must account for design criteria.

Here are some factors that determine how many gallons per day your community septic or other wastewater system must be able to handle:

  • Capacity in gallons per day is determined by state and local design specifications.
  • These regulatory agencies calculate required treatment capacity in terms of maximum gallons used per person per day or maximum flow per bedroom per day, etc.
  • Commercial wastewater systems use more complex formulas that take their specific usage into account. The hotel mentioned above might need to account for 75 gallons per bed per day but might also have a restaurant and a bar attached for which another 12 gallons per seat per meal would have to be added.
  • Design criteria must also assume the level of pollution present within wastewater from different sources. Very dirty wastewater takes longer to treat which means systems must have higher capacity than what is released to give the system the time needed.

Here is an example of a design criteria matrix from an actual state regulatory agency:

An example design criteria table for wastewater system capacity in residential and commercial applications.
Design criteria differ based on locality.
  • Design criteria tables such as the one above provide a starting point to determine size, but in most cases, regulatory agencies grant variances based on actual flow and treatment level.
  • We at Aqua Tech will research the design criteria required for your project and budget around them. As the build gets closer, we reevaluate your treatment needs and work with civil engineers and regulatory authorities to ensure regulatory compliance without excess expense.

Bottom line: Use this table to get a rough estimate. When you’re ready, let’s talk and get more specific.


*Soils differ in how much moisture they can absorb per hour. Very dense soil might only be able to absorb one tenth of a gallon per square foot every hour while porous soil can absorb almost a full gallon per square foot. Soil absorption per hour is called its “loading rate.” The higher the loading rate the smaller the drip field needed.

Wastewater treatment uses natural biological processes to protect the environment from contaminants in sewage.

Wastewater poses several threats to the environment. Micro organisms which digest the suspended organic matter (Total Suspended Solids – TSS) in sewage use up the dissolved oxygen (DO) present in the water. The rate of this digestion can be measured as Carbonaceous Biological Oxygen Demand (CBOD). Water with high CBOD can deplete dissolved oxygen in waterways thereby suffocating wildlife.

septic tank cutaway
A common septic tank design

All wastewater treatment from septic tanks to municipal systems use gravity to settle out most solids. After settling, smaller organic particles remain suspended in the effluent. The settled wastewater then moves into biological treatment which increases the density of micro organisms in an oxygen rich environment. When done properly, biological treatment can neutralize the oxygen depleting effects of wastewater.

Wastewater treatment also removes chemical pollutants.

infographic of nitrification and denitrification in wastewater
Conversion of ammonia to nitrate and nitrate to nitrogen gas in wastewater.

One byproduct of human metabolism, ammonia, can poison watersheds through untreated sewage. Beneficial bacteria naturally occurring in wastewater use DO to convert toxic ammonia into the nutrient, nitrate. That’s good, but not quite good enough. When nitrate along with another nutrient, phosphorus, enters the environment, they can cause plant overgrowth that chokes waterways. Conveniently, other wastewater bacteria turn nitrate into nitrogen gas and mineralize phosphorus which settles out of the resulting effluent.

cutaway of an aerobic wastewater treatment plant
https://communitysewer.com/2020/12/16/biotank-overview/

These bacteria multiply into a slime layer called, “biofilm” in the biological reactor. Advanced treatment systems achieve high biofilm density by giving it a lot of surface area (media) to grow upon. The greater the surface area, the higher the treatment level.

Aqua Tech uses the latest in biofilm media technology to achieve maximum treatment in a very small treatment plant.

Wanna know more about wastewater or how we can take care of it for you?

Several places around the US are currently experiencing a construction boom and we’re delighted to be a part of it. Here’s a mixed use system that our engineers have just designed.

This system is designed to treat 37,000 gallons of wastewater per day.

This particular system was designed to treat residential and commercial wastewater at the same time. Notice that the effluent (outflow) discharges at ground level. This is a septic system with no leach field!

Here’s the secret:

This private wastewater treatment plant removes nearly all of the Biological Oxygen Demand (BOD), Total Suspended Solids (TSS), and Total Nitrogen (TN).

Got an enquiring mind? Here’s an overhead view of the same sewer system design:

Here’s what a similar system looks like in real life:

Wastewater treatment plant overhead view
A 3-tank in-ground system with a methanol doser and all-weather controls

Whether you’re an engineer or a real estate developer, we can help you put together a system to meet your needs. Just click the button below!