The qualities of wastewater are frequently diverse and may include minimally biodegradable, or harmful chemicals, or both. To preserve the environment, these wastewaters are normally treated before being discharged into the environment, or to municipal wastewater-treatment plants, for further treatment.
Microorganisms are used as a method in secondary wastewater treatment techniques, to biologically eliminate pollutants from wastewater. Secondary biological processes can be aerobic or anaerobic, with each utilizing a unique bacterial community. Under specific conditions, coupled anaerobic-aerobic processes may also be used.
However, selecting the optimum secondary biological treatment procedure for wastewater treatment is extremely difficult.
Why is it critical to choose a certain secondary biological treatment process?
Different wastewater discharge regulations apply to different sectors and businesses. To appropriately target and treat the pollutants produced by each application, treatment systems must be tailored around it. This is why, for secondary-stage wastewater treatment, it is critical to select the appropriate biological wastewater treatment technique.
How to select the best secondary biological treatment process for WWT?
When it comes to wastewater treatment technologies, there are numerous options available within the various treatment phases. Secondary stages are typically made up of biological wastewater treatment systems, which come in a variety of configurations.
To select the best solution for a specific application, numerous factors must be carefully considered.
The following are the considerations of the biological wastewater treatment process:
3 general considerations are:
- The system's occupied area, or how much land it will take up on-site;
- Construction costs, the amount of money necessary to develop the system;
- Operating expenses are the costs involved with using the system on a daily basis.
2 Specific considerations are:
- Hydraulic retention time (HRT): The length of time the effluent is subjected to the process is referred to as the HRT.
- SRT (sludge retention time): SRT is the amount of time a unit of sludge (or another bio medium) is active within the reactor.
All five of these parameters, are considered in the treatment selection, and design of biological wastewater treatment systems. During decision-making processes, weights are frequently assigned to each criterion, and subsequently, points are assigned to each approach for each of those criteria. The points are multiplied by the weights, and the results are used to numerically compare each choice.
Secondary stage biological treatment processes of wastewater
There a?re some biological processes which include:
1: Process of Activated Sludge (ASP)
It is a suspended solids system that aerates loose biological media, before pumping it to a clarification tank to settle. Return active sludge is the clarifier sludge, which is re-circulated back into the reactor.
· Occupied Area: HRT: Second lowest, Second largest HRT: 4-10 hours
· Construction costs: Second highest SRT: Least expensive
· Low operational costs
2: Sequencing Batch Reactor (SBR)
It is a kind of an ASP that lacks a separate clarifying tank. Instead, the solution is allowed to settle after a sufficiently long retention time, and the resulting supernatant is pumped to tertiary treatment.
· Occupied Area: Second shortest HRT: Second longest, 6-12 hours
· Low operational costs
3: MBBR (Moving bed biological reactor)
In MBBR, a biofilm adheres to small specialized carriers that are transported around the reactor, by aeration bubbles in a fixed film system. MBBR, like ASP, is followed by a clarifying step.
· Occupied Area: HRT Lowest, Smallest: 1-5 hours
· Highest Construction Costs
· Low operational cost
What you see above are tips to consider when choosing a biological wastewater treatment procedure. Inevitably, the weighting of deciding criteria is entirely reliant on what the engaged organization considers, to be more significant, and design firms can always supply more thorough information, to aid in decision making.
How can we assist?
Each of these treatment procedures has advantages and disadvantages that can make them suitable, for a particular purpose. In terms of operating, all four are low-cost, although construction costs are greater for reactors that require more land area.
Netsol Water provides the most effective biological secondary wastewater treatment methods. To treat wastewater efficiently, we offer aerobic, anaerobic, trickling filters, activated carbon, MBBR, MBR, etc.