When the owner of a wastewater treatment plant (WWTP) first hatches the idea of the project, there are many things to consider: tender application, site selection, process selection and design, physical layout of the plant, hiring a construction contractor, and starting up the plant and beginning regular operation. Each of these steps in taking the complete wastewater management process from an idea to a functioning plant is critical and demands expert guidance. If the plant owner has prior experience in wastewater treatment, they may themselves be the source of some of that expertise.
Many of the steps overlap and impinge on each other. For example, each of the first four in the list must be considered together since the choices made in one become considerations for the others.
This article will look at these steps and the interlocking effects that each decision and execution have on the other considerations.
Tender Application and Site Selection
The starting point of a WWTP project depends on the type of entity involved and the type of contract arrangement to be made with the engineering, construction and operating companies you plan to use. As a private operator, you may need to apply for a tender from the government where you plan the project. This site offers information on how to make this application for a plant anywhere in the world.
There may be several possible choices for the WWTP location in some municipalities. In others, there may be little choice of land available, and of some of the other factors we’ll discuss.
One of the most critical factors in this selection is the ease of getting the feedwater to the treatment site. Usually the lowest elevation relative to the feedwater sources is the most desirable since that reduces the need for pumps. Ease of discharge into the intended river, lake, etc., is an additional element to consider. Depending on the topography and area covered by a community, costs can sometimes be reduced by using several plants, simplifying the sewage network.
Other considerations are the space available and the amount of excavation required to make the site suitable for a WWTP. As we’ll see further on, process choice impacts these factors.
Process Selection and Design
The choice of the wastewater treatment process to be employed in the wastewater management system is a major step in getting to the finish line.
The process selection depends on the character of the feedwater, the plant space available, and the environmental sensitivity of the discharge area. Some processes are easier than others to expand for future requirements, which should also be considered. Sometimes earlier feasibility studies have determined the process technology to be used, and that’s specified in the tender.
Now, as we consider the design process, the interaction of the steps in this process gets complex.
Wastewater management design can take up to several weeks or months, working with traditional engineering teams. For many years, this was the norm. Engineers would laboriously perform manually all the complex calculations required to produce a process design. Then, if the client wanted to consider a different process, much of the work would have to be duplicated. In an industry where tomorrow is usually not soon enough, this engineering work and the resulting delay would be painful for all involved.
Over the last decade, Transcend Water, a leading wastewater management design firm, has developed the Transcend Design Generator to automate 90 percent of the preliminary design process, greatly compressing the time from concept to construction of WWTPs.
Construction and Operation of the Wastewater Management System
Once the process and physical design of the plant are completed, construction can begin. If you haven’t selected a construction contractor earlier in your process, your designer should be able to help you with that selection. It’s actually best to have the contractor work with the designer to exchange ideas and ensure the contractor is following the design.
The same applies for hiring operators to put the plant into operation. This may be done with a contractor who manages the entire operation, or with individuals directly responsible to the owner of the plant. Either way, the sooner the operators can be in communication with the designer and the constructor, the better they will operate the plant as the designer and constructor intend.
As we mentioned at the outset, the steps in taking a WWTP project from conception to operation should be all interconnected. When you have selected the site for your plant, the best plan is to get all the players involved as soon as possible. The designer is often the best choice for coordinating all these activities.
If the Transcend Design Generator seems like a good choice, you can contact Transcend Water’s experts through their website to learn more about their approach and capabilities.
