Nutrients in Wastewater

Can we survive without water? The answer to that question is no and that is why wastewater is a topic that should be of significance to everyone!

So where does wastewater come from?  There is a long list of answers; however frequent practices such as using the washing machine and flushing your toilet are activities that everyone can relate to. The creation of wastewater is inevitable, that is why it is vital to continuously develop wastewater treatment and reuse facilities. Nonetheless, we can help reduce the amount of wastewater being created. Here’s a fun fact for you, did you know that a tunnel car wash facility can wash from 100 to 1,000 cars a day, using an average of 80 gallons of water per car? That can potentially mean that 80,000 of gallons of water is used per day per facility! Wow!

(Image Source: Green, 2013)

Unfortunately, new constituents are contentiously being found in wastewater everyday hence making the treatment of wastewater more and more challenging. To ensure that wastewater is used efficiently and effectively, it is necessary to understand and identify the constituents of wastewater as much as possible and operate the treatment plants accordingly.

There are many constituents of wastewater that I do not know where to start from! Feces, hair, food and pathogens such as bacteria and viruses are constituents that are highly predictable. However, there is major concern on a certain constituent which is pharmaceuticals as they impact aquatic organisms but that is a story for another day.

My focus in this blog is towards the nutrients in wastewater and how we can make the most of them by using them beneficially.  Some valuable nutrients in wastewater are phosphorus, nitrogen, and potassium however these nutrients are lost from conventional wastewater treatment plants. Research in Germany is being conducted for regaining these nutrients in the form that can be used for agriculture as plants can’t grow without those nutrients (Fraunhofer-Gesellschaft, 2010).

In most cases, farmers usually use artificial fertilisers to supply their crops with the necessary nutrients but we can’t depend on these artificial fertilisers in the long-term! Why is that the case? Well due to the world’s growing population there is the need to progressively increase the supply of food which will consequently result in an increase in usage of fertilisers. You might ask what is the problem with global demand increase for food ? Unfortunately, the process of increasing productivity of food happens through the use of fertilisers and water which are limited in supply.

Image Source: (Osborne, 2012)

However, there should be huge concerns NOW as the deposits of rock phosphates required for producing phosphate fertilisers are becoming limited already (Fraunhofer-Gesellschaft, 2010). The research based in Germany in working on new and innovative methods to recover magnesium- ammonium- phosphate and organic phosphorus from wastewater. The aim and motivation behind this initiative is to offer these nutrients as a fully functional product that can be used in agriculture depending upon the properties of the cultivated plants and soils (Fraunhofer-Gesellschaft, 2010).

It’s something to ponder about isn’t it?

How about the developing countries that have limited resources and are unable to recover these nutrients? Can they benefit from these nutrients found in wastewater in a different way? Interestingly, I believe the answer to that question is a maybe. There are many question marks about the idea of using treated (and sometimes untreated as you will see later in this blog) wastewater for  irrigation purposes in agriculture. The obvious benefit is that the crops could gain those nutrients and enhance their growth but there could be too many health and environmental issues involved that can’t be manageable.

In my vlog I discuss the use of wastewater for irrigation purposes in agriculture and try to outline how the constituents of wastewater has a MAJOR impact on whether this action is possible or not. Watch my vlog below to get an idea of the importance of this matter!

To get a more thorough understanding of this interesting topic have a read about the Guidelines for wastewater irrigation.

After watching my vlog you would have got a solid idea of the use of wastewater for irrigation.

Many countries have fantastic wastewater treatment plants but unfortunately some places have a lack of financial resources at municipal and provincial levels for wastewater treatment. Pakistan is one of many countries where wastewater treatment schemes are limited and  the use of wastewater for irrigation purposes is a HUGE conundrum in Pakistan. Many (over 80%) Pakistani communities with a population of over 10,000 people use untreated wastewater for irrigation for many reasons mainly due the absence of another water source, due to the high nutrient value present and since farmers earn a higher income using wastewater compared to freshwater which in a lot of cases is vital for livelihood.

One of the health issues involved in the use of untreated wastewater in Pakistan were a high increase in hookworm infections with the people who used wastewater and  the commencement of heavy metal accumulation in soil and plant material in Faisalabad, a city with large scale industry.

Source: (Wastewater Use in Irrigated Agriculture)

Can you see why it’s a really significant problem?

There are many benefits but plenty of  health and environmental issues!

Untreated wastewater irrigation to vegetable crops in Pakistan.                                       Image Source ( Ayub et al, 2017).

Using more wastewater treatment schemes is currently not an option for such countries, so how can we manage the negative effects of wastewater in such cases? Regularly managing irrigation water, ground water and regular treatment of those exposed to wastewater have been discussed.

However, is that suitable and enough over the long-term? Definitely Not.

I would love to hear your opinions about this topic in the comments below

Thanks for reading!

Mo