Are you looking for a cost-effective and affordable solution to recycle your wastewater in your home and villa? Then you have come to the right place!
As the world population grows, so the demand for clean water. That is why Compact Wastewater Treatment Plants (CWTPs) are increasingly popular solutions for home and businesses. CWTPs are perfect investments for home and villa owners who want to save money and reduce their environmental footprint.
The objective of CWTPs is to treat the wastewater to an extent that it offers some re-use options; the most common one being irrigation. However, additional treatments may be applied for other recycling possibilities such as toilet flushing and floor washing.
Some brief explanations for a basic understanding of domestic & municipal wastewater treatment
- Municipal & domestic wastewater are mainly composed of biodegradable organic matter either dissolved or in suspension.
- There are two main processes used for the degradation of organic matter. These are aerobic (presence of oxygen) and anaerobic (no oxygen).
- Both aerobic and anaerobic degradation occurs due to the presence of specific groups of microorganisms that feed on the organic matter. These processes occur naturally – this is how nature cleans up itself. In a wastewater treatment plant, the role of nature is just imitated but in such a way that greater pollution loads can treated more quickly in one single place.
Now maybe you would like to know what`s the difference between a septic tank and a CWTP? So, we`ll try our best to make it as simple as possible
A septic is generally composed of two chambers. The wastewaters from your house collect into the first chamber. Oil & grease (if you don`t have a grease trap) accumulates at the top, while the heavy particles settle at the bottom. The middle layer is composed of wastewater with suspended solids.
The water (middle layer) then overflows into the second chamber by the help of a tee shaped pipe. This prevents the top scum layer to get into the 2nd chamber. In this 2nd section further settling will take place and clear water exits at the top to percolate the soil or is spread over a leaching field.
Two main treatment processes take place in a septic tank; namely, sedimentation and anaerobic degradation. A septic system shall provide enough residence time to allow settlement of 70 % of suspended particles, between 25 and 30 % degradation of organic matter and treatment of approximately 9 % of organic nitrogen.
Compact Wastewater Treatment Plants
The main difference between a CWTP and a septic tank, is that the 2nd chamber of a CWTP acts as an biological reactor. It is interesting to note that some new models of CWTP are comprised of only one aeration chamber (biological reactor) – no septic section.
Another difference is also in the system design, but this won`t be discussed here as this includes complex calculations and different CWTP manufacturers follow guidelines available in their country. There are mainly 2 different types of biological reactors which will be briefly discussed below.
The 2 most common type of biological reactors
The 2 most commercialized CWTP are the Sequenced Batch Reactor (SBR) and the Submerged Aerated Fixed Film (SAFF). Although both systems use oxygen supplied by an air blower to degrade organic matter and for nitrification, they differ a lot in the way they treat the wastewater.
In the SBR system, the organic matter is degraded by aerobic microorganisms in suspension while in the SAFF system, the organic matter is degraded by aerobic microorganisms attached to fixed supports. In the SBR plant, the wastewater is treated in batches whereas in a SAFF reactor, the water is treated continuously.
Compared to the SAFF, the SBR includes more mechanical components. But the SBR can be automated in various ways and if well maintained produces water of better quality.
One important advantage of the SBR technology, is that, if your septic system provides enough space (600 L per person), then it is possible to adapt the system (which comes in the form of a kit) to your septic tank.
Some SBR suppliers also propose a double chamber tank (or even single chamber) where all the wastewater is aerated simultaneously; this technique helps to reduce odor nuisances cause by septic water and also reduce the frequency of septic tank desludging.
Note: This article is meant to give you some basic knowledge of Compact Wastewater Treatment Plants, we won`t go further with complex technical details at this stage.
Objectives of the Treatment
The main target is to treat the water so as it reaches at least irrigation norms as per WHO guidelines. However, to be able to reuse the water, it needs to be stored in an additional tank and disinfected either by chlorine or ultraviolet radiations prior to reuse. The water can be further treated (by using combinations of filtration techniques) for other recycling options – toilet flushing, car & floor washing.
It is good to note that in some regions where water is readily available and the water table (ground water level) is high, CWTP is an ideal investment to avoid contamination of underground water by sewage.
NOTE: Recycling water is essential. Building dams & extensive pumping of river water affect aquatic life and don`t forget that rivers and lakes are sources of food. Its easy to say we must capture more water but don`t forget that we live in an ecosystem and animals need it too.
On average an individual consumes 175 liters per day. If out of it we can reuse 30 % of the overall daily consumed water, then it is 30% less water that we will take from natural courses.
Wastewater recycling coupled with rainwater harvesting can help you become completely autonomous in your daily water consumption. Also, why not think to become autonomous in energy also by producing your own electricity from solar panels – who knows maybe in future years this mode of living will become a must for human survival!
