LAOTSS® Technology

In the world, according to the information from the world Bank group released on March 19, 2020, only 20% of the wastewater generated is treated, with the rest being discharged directly to surface water, leaving many water sources contaminated.

LAOTSS® treatment technology offers a cost-effective solution that seeks to be environmentally friendly, with its operation mimicking some of the natural phenomena found in self-depurative water bodies, i.e. a river or lake in which the processes of pollutant degradation occur through bacterial action, that in the presence of dissolved oxygen within the water develop an aerobic microbiota, without generating odors. Such processes allow water bodies to maintain conditions appropriate for aquatic life. However, the purification of a river has limitations in terms of pollutant loads and speed at which these pollutants degrade. Therefore, a LAOTSS® system controls the conditions that affect biological mechanisms for optimization, thus reducing the sanitation time from 20 days that would have taken a natural system to less than 24 hours.

The treatment system consists of a tank equipped with aerators with a suspended bacterial culture called activated sludge. The purification mechanism that takes place is very simple: bacteria consume the organic matter present in the water by incorporating it into their metabolism as a carbon source that allows them to obtain energy to develop its functions. Bacteria form agglomerations that are denser than water allowing their separation by sedimentation, once the purification process has been carried out in a biological reactor (tank with suspended bacteria) the water is passed into a sedimentation tank in which water flows slowly allowing bacteria flocs to deposit at the bottom, obtaining a clear effluent from the top of the tank and a concentrate of sludge-like bacteria from the bottom, this sludge is returned to the biological reactor to maintain a high concentration of bacteria some of which will, eventually, be purged form the system.

In Figure 1 we have a schematic representation of the activated sludge process.

representacion esquematica del proceso aclara
Figure 1. Activated sludge flow diagram

The biological process requires that the water in the influent is free of large waste (e.g. bags, cans, etc.) as well as sand. To achieve this, pretreatment facilities are placed before the biological reactor. These systems commonly consist of fine and coarse grids, in which the large solids are retained. In the case of sand, the units designed to remove it from the water are called sand traps, which basically consist of a channel through which the water is circulated at a very low speed, so that the sands suspended in the water are sedimented at the bottom of the channel from which they are constantly removed.

After the pretreatment stage, the water must be sent to the biological reactor, this is commonly done by pumps, for which a lift station is necessary where the pretreated water will stay for few minutes until it is sent to the treatment plant by one or two pumps1.

The purged sludge from the sedimentation is called residual sludge and should be treated to decrease its organic content and remove as much water as possible in order to facilitate its transportation and/or final use, for this purpose the sludge is treated in aerobic or anaerobic digesters and dehydrated commonly in drying beds, although there are other devices such as press filters.

A complete flow diagram of the processing process is presented in Figure 2.

diagrama del proceso aclara
Figure 2. Flow Diagram of the LAOTSS process

Design bases of Bclear’s wastewater treatment plants with LAOTSS Technology®

LAOTSS Technology® consists of a system of Activated Sludge in Total Oxidation combined with a state-of-the-art Sequential Systems process, thus resembling the natural process with which contaminated water is treated in rivers, lakes and seas.

1 3 or more pumps can sometimes be installed. Depends on the flow to be treated; For small plants (68473 GPD and smaller) it is advisable to put only one pump to avoid destabilizing the process by overloading.

The first wastewater treatment plants were developed with empirical methods, however, the water treated by these systems did not meet the strict discharge standards that emerged from the 1970s, this motivated further developments advanced wastewater treatment.

The activated sludge system proved so reliable and safe that currently more than 70% of the globally treated water is done using the activated sludge system in its different modalities.

LAOTSS Technology® has the modalities of Total Oxidation – which allows a high efficiency in removal of contaminants linked to a very low production of sludge waste –, and a Sequential System that allows a perfect control of the process for the treatment of pollutants.

The IESSUS engineering firm specializes in developing series of treatment plants with LAOTSS® technology; designed according to national and international regulations issued by governing bodies like EPA in the US and SEMARNAT in Mexico, and to the user’s needs.

For the all series, reengineering techniques have been used that make the plants very functional and extremely simple in terms of operation and maintenance. To achieve this, the following design criteria have been considered:

  1. Perform gravity driven liquid transportation rather than pumping to reduce corrective and preventive maintenance.
  2. Reduce pipe distance and minimize the number of special parts to prevent blockages.
  3. Simplify plant operation.
  4. Reduce the required maintenance.
  5. Prevent emergency situations.
  6. Facilitate corrective and preventive maintenance operations.
  7. Compliance with applicable regulations.

Bclear Wastewater Treatment Plants water quality

Experience the treated water quality in Bclear's Wastewater treatment plants

Note: If water contains inorganic colorants in the influent, the effluent could contain coloration

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