Wastewater Treatment and Reuse | Moinhos Ambiente

Domestic and industrial human activity generally produce large amounts of wastewater, with high levels of organic and chemical contamination. The rejection of contaminated water in the environment without any treatment, destroys ecosystems, deteriorates the quality of aquifers and waterways, leads to poor water quality and contributes greatly to the spread of diseases and epidemics.

Moinhos Água e Ambiente is in tune with the growing worldwide demands on the quality of wastewater rejected in the environment, whether from domestic or industrial origin, as well as independently of its application and flow requirements (low, medium and high):

  • Pretreatment
  • Primary Treatment
  • Secondary Treatment
  • Tertiary Treatment
  • Combined Processes and MBR
  • Sludge Treatment
  • Gaseous Effluents

  • Pretreatment
  • Primary Treatment
  • Secondary Treatment
  • Tertiary Treatment
  • Combined Processes and MBR
  • Sludge Treatment
  • Gaseous Effluents

The pretreatment step is solely constituted by physical processes. In this stage, the materials of suspension, thick solids and sand are removed, which in addition to hindering the following treatment processes, could damage or shorten the useful life of the equipment and organs of the WWTP.

Depending on the quality of the water being treated, several processes may be required:

  • Gradation
  • Tamping
  • Dehulling

The primary treatment consists solely of physical and/or chemical processes. In this step, the following treatments can be performed:

  • Equalization of loads and flows through the installation of a tank with adequate volumes and residence times.
  • Neutralization of the effluent through the addition of chemicals.
  • mplementation of physical-chemical processes (only in special cases, especially in industry): coagulation and flocculation.
  • Primary, conventional and lamellar decanting.
  • Recourse to processes of removal of fats, oils, or hydrocarbons, in cases like in the dairy and petrochemical industry, through flotation processes, technology developed by Moinhos Água e Ambiente: MAFLOTtech.
  • Advanced oxidation with ozone, through MAOZONEtech technology, of complex compounds with non-biodegradable or difficult biodegradability chains, making possible their biological treatment and/or preventing them from being released into the environment.

Secondary effluent treatment is a biological process that uses a wide range of microorganisms, mostly bacteria. These microorganisms convert the dissolved organic matter into simple substances and biomass.

Depending on the environment, various types of biological processes can be used:

  • Conventional biological treatment, through activated sludge, with liquid solid separation by decantation.
  • Biological treatment in SBR.
  • Biological treatment with biomass fixed to supports, with solid-liquid separation by decanting.

Note: All these processes are possible to apply with or without nutrient removal (nitrification-denitrification in anoxic systems).

The purpose of tertiary treatment (also called polishing) is to remove unwanted elements like SS, COD, phosphorus and specific compounds (pesticides, metals or detergents). This type of treatment is designed to raise the quality of the effluent to be discharged into its natural or reused environment.

Depending on the needs of each industry, the tertiary treatment processes are very diverse, however the following processes can be mentioned:

  • Physical/chemical processes: coagulation/flocculation, followed by decantation or flotation.
  • Ozonization through the MAOZONEtech system for color removal, foaming, deodorization, disinfection, oxidation of refractory compounds and endocrine disruptors.
  • Filtration.
  • Microfiltration.
  • Ultrafiltration through MAUFPUREtech systems.
  • Reverse osmosis, through MAROPUREtech systems.
  • Chlorination for the removal of bacteria.

Combined processes consist of compact units comprising several steps.


Active sludge process associated with a microfiltration membrane for the separation of data, which includes the advantage of having a superior quality to the treatment, allowing its safe reuse.

It is a technology that, through its potential, has revolutionized the wastewater sector.

Moinhos Água e Ambiente has developed its own system, the CompactMBR.

O crescimento constante do volume de lamas gerado pelo tratamento de água, ligado à evolução demográfica, à evolução industrial e ao aumento da produção de efluentes, conduz a restrições cada vez mais rigorosas no que respeita a este tema.

The steady increase in the volume of sludge generated by water treatment, coupled with demographic trends, industrial developments and increased effluent production, leads to increasingly stringent restrictions in this area.

A thorough knowledge of the sludge to be treated (classification and characterization in terms of their origin and composition), as well as their final destination, represent two essential elements to be considered in the definition of sludge treatment.

The treatment of sludge in order to reduce its volume and to turn it into a recoverable product is now a necessity.

Moinhos offers the following technical solutions:

  • Reduction of sludge volume: ozone oxidation processes, thermal sludge drying and aerobic sludge digestion.
  • Sludge densification systems, both by decantation and by flotation, through the MAFLOTtech system.
  • Dehydration of excess sludge by centrifugation, strip filter or plate press.

Certain gaseous effluents released at urban wastewater lift stations, WWTPs and in some industrial processes carry contaminants that may be harmful to the environment and human health or are uncomfortable to smell.

Moinhos Água e Ambiente has developed and proposes a technology for the treatment of these gases, MAOZONEtech, whose design depends on the origin of the effluent to be treated and the respective flow.

Strong arguments for the MAOZONEtech option include:

  • The high oxidizing and deodorizing power of ozone, associated with ozone-effluent contact technology, specifically developed by Moinhos Ambiente.
  • The production of ozone is carried out in loco, being only electrical energy required. This avoids all logistics and handling with corrosive and dangerous chemicals used in conventional processes.

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Moinhos Água e Ambiente

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