Why Wastewater Treatment is Crucial in Our Society

Wastewater treatment is essential for maintaining proper balance throughout the world’s ecosystems. Wastewater contains toxic substances that harm wildlife and humans, including (and especially) aquatic life. This toxic water comes from a variety of sources, including sewage systems.

When organic matter enters a water source, like a river, aquatic lifeforms consume it as food. As the organic pollutants break down, the animals require more oxygen for the process. This leaves less oxygen in the water overall. When oxygen levels become dangerously low, animals in the water suffocate and die.

effluent-treatment-plant

Wastewater is toxic

Although some fish and other animals can break down toxins, toxic water is a serious risk to human health and is responsible for millions of deaths each year, mostly in developing nations.

Unclean water also causes diseases like cholera and schistosomiasis. Although these diseases generally occur in developing countries that don’t treat their wastewater, they can occur anywhere.

What is wastewater treatment? How does it work?

Wastewater treatment is the process of filtering contaminants out of water that has been previously used for another purpose. This process can occur both naturally and through manmade efforts.

Our ecosystem has a natural water treatment system that involves microorganisms that eat waste material, along with different layers of substrate and soil that filter the water as it absorbs into the earth. However, this process is too slow to efficiently filter the enormous amount of wastewater produced by humans. That’s where water treatment facilities come into play.

Water treatment plants are complex systems

What exactly happens at a wastewater treatment plant? While there are different methods, some of the systems use similar components. For example, the Four Rivers Sanitation Authority in Illinois treats wastewater by first pumping it to a higher elevation for gravity to pull the water through the first part of the treatment and filtering process.

The treatment process begins by filtering out the largest debris like plastic to prevent the pumps from becoming damaged. Debris that gets filtered out is then sent to a landfill.

Next, abrasive materials like sand and coffee grounds are filtered out of the wastewater. This grit is separated and sent to a landfill.

Settling tanks are then used to filter out fats, oils, and greases. These tanks also separate solids, most of which are sent to a separate processing facility. A small amount of solids are sent to the aeration tanks to maintain the proper environment required for microorganisms to devour the solids.

The water is then processed through a second set of settling tanks and is then disinfected with high-powered bleach. Sodium bisulfite is used to reduce the amount of chlorine in the water to make it less harmful to plant life when it’s discharged into the river.

What is in wastewater, exactly?

Since wastewater comes from human use, thousands of contaminants are present, although not all are present in every batch of water. In general, there are both inorganic and organic compounds found in wastewater.

sewage_sludge

Organic matter found in wastewater includes:

  • Proteins
  • Fats
  • Oils
  • Greases
  • Synthetic compounds from detergents
  • Carbohydrates

Inorganic matter found in wastewater includes:

  • Copper
  • Lead
  • Nickel
  • Magnesium
  • Potassium
  • Zinc
  • Sodium

Most of these contaminants come from industrial wastewater and aren’t easily broken down. When these inorganic compounds collect in water sources, they build up over time, making the water increasingly toxic to animals and humans.

Other matter found in wastewater includes:

  • Nutrients: High levels of nitrogen and phosphorous create “dead zones” by feeding large algae blooms. These blooms block sunlight, causing plants to die. Bacteria then proliferate by feeding on the dead plant matter.
  • Microorganisms: Harmful microorganisms include E. coli, parasites, and bacteria.
  • Pharmaceuticals: Pharmaceuticals enter wastewater through human waste and people flushing drugs down the toilet.

Wastewater treatment can help with water scarcity

There are many places across the world that experience droughts and water shortages on a regular basis. Without treating wastewater, drinking water sources become (and remain) contaminated. This includes rivers, lakes, and streams.

Treating wastewater in these areas would provide residents with a clean source of water to use for drinking, washing clothes, and bathing. After continually treating the wastewater, it would eventually bring the rivers, lakes, and streams back to a less-polluted state over a long period of time.

However, getting a treatment system set up takes money, time, and resources. The nations that need it the most can afford it the least. However, there are people and organizations working on solutions to this problem.

It’s not an overnight fix, but hopefully, one of those organizations will soon create a successful model that works for developing nations.

Things You Should Know About the Different Uses of Biochar

Biochar is a carbon-rich, fine-grained residue which can be produced either by ancient techniques (such as covering burning biomass with soil and allowing it to smoulder) or state-of-the-art modern biomass pyrolysis processes. Combustion and decomposition of woody biomass and agricultural residues results in the emission of a large amount of carbon dioxide. Biochar can store this CO2 in the soil leading to reduction in GHGs emission and enhancement of soil fertility.

Biochar holds the promise to tackle chronic human development issues like hunger and food insecurity, low agricultural productivity and soil depletion, deforestation and biodiversity loss, energy poverty, water pollution, air pollution and climate change. Let us have a close look at some of the most promising applications of biochar.

 

1. Use of biochar in animal farming

At present approx. 90% of the biochar used in Europe goes into animal farming. Different to its application to fields, a farmer will notice its effects within a few days. Whether used in feeding, litter or in slurry treatment, a farmer will quickly notice less smell. Used as a feed supplement, the incidence of diarrhoea rapidly decreases, feed intake is improved, allergies disappear, and the animals become calmer.

In Germany, researchers conducted a controlled experiment in a dairy that was experiencing a number of common health problems: reduced performance, movement disorder, fertility disorders, inflammation of the urinary bladder, viscous salivas, and diarrhoea. Animals were fed different combinations of charcoal, sauerkraut juice or humic acids over periods of 4 to 6 weeks.

Experimenters found that oral application of charcoal (from 200 to 400 g/day), sauerkraut juice and humic acids influenced the antibody levels to C. botulinum, indicating reduced gastrointestinal neurotoxin burden. They found that when the feed supplements were ended, antibody levels increased, indicating that regular feeding of charcoal and other supplements had a tonic effect on cow health.

2. Biochar as soil conditioner

In certain poor soils (mainly in the tropics), positive effects on soil fertility were seen when applying untreated biochar. These include the higher capacity of the soil to store water, aeration of the soil and the release of nutrients through raising the soil’s pH value. In temperate climates, soils tend to have humus content of over 1.5%, meaning that such effects only play a secondary role.

Indeed, fresh biochar may adsorb nutrients in the soil, causing at least in the short and medium term – a negative effect on plant growth. These are the reasons why in temperate climates biochar should only be used when first loaded with nutrients and when the char surfaces have been activated through microbial oxidation.

The best method of loading nutrients is to co-compost the char. This involves adding 10–30% biochar (by volume) to the biomass to be composted. Co-composting improves both the biochar and the compost. The resulting compost can be used as a highly efficient substitute for peat in potting soil, greenhouses, nurseries and other special cultures.

Because biochar serves as a carrier for plant nutrients, it can produce organic carbon-based fertilizers by mixing biochar with such organic waste as wool, molasses, ash, slurry and pomace. These are at least as efficient as conventional fertilizers, and have the advantage of not having the well-known adverse effects on the ecosystem. Such fertilizers prevent the leaching of nutrients, a negative aspect of conventional fertilizers. The nutrients are available as and when the plants need them. Through the stimulation of microbial symbiosis, the plant takes up the nutrients stored in the porous carbon structure and on its surfaces.

A range of organic chemicals are produced during pyrolysis. Some of these remain stuck to the pores and surfaces of the biochar and may have a role in stimulating a plant’s internal immune system, thereby increasing its resistance to pathogens. The effect on plant defence mechanisms was mainly observed when using low temperature biochars (pyrolysed at 350° to 450°C). This potential use is, however, only just now being developed and still requires a lot of research effort.

3. Biochar as construction material

The two interesting properties of biochar are its extremely low thermal conductivity and its ability to absorb water up to 6 times its weight. These properties mean that biochar is just the right material for insulating buildings and regulating humidity. In combination with clay, but also with lime and cement mortar, biochar can be added to clay at a ratio of up to 50% and replace sand in lime and cement mortars. This creates indoor plasters with excellent insulation and breathing properties, able to maintain humidity levels in a room at 45–70% in both summer and winter. This in turn prevents not just dry air, which can lead to respiratory disorders and allergies, but also dampness and air condensing on the walls, which can lead to mould developing.

As per study by the Ithaka Institute’s biochar-plaster wine cellar and seminar rooms in the Ithaka Journal. Such biochar-mud plaster adsorbs smells and toxins, a property not just benefiting smokers. Biochar-mud plasters can improve working conditions in libraries, schools, warehouses, factories and agricultural buildings.

Biochar is an efficient adsorber of electromagnetic radiation, meaning that biochar-mud plaster can prevent “electrosmog”. Biochar can also be applied to the outside walls of a building by jet-spray technique mixing it with lime. Applied at thicknesses of up to 20 cm, it is a substitute for Styrofoam insulation. Houses insulated this way become carbon sinks, while at the same time having a more healthy indoor climate. Should such a house be demolished at a later date, the biochar-mud or biochar-lime plaster can be recycled as a valuable compost additive.

4. Biochar as decontaminant

As a soil additive for soil remediation – for use in particular on former mine-works, military bases and landfill sites.

Soil substrates – Highly adsorbing and effective for plantation soil substrates for use in cleaning wastewater; in particular urban wastewater contaminated by heavy metals.

A barrier preventing pesticides getting into surface water – berms around fields and ponds can be equipped with 30-50 cm deep barriers made of biochar for filtering out pesticides.

Treating pond and lake water – biochar is good for adsorbing pesticides and fertilizers, as well as for improving water aeration.

5. Use of biochar in wastewater treatment – Our Project

The biochar grounded to a particle size of less than 1.5 mm and surface area of 600 – 1000 m2/g. The figure below is the basic representation of production of biochar for wastewater treatment.

We conducted a study for municipal wastewater which was obtained from a local municipal treatment plant. The municipal wastewater was tested for its physicochemical parameters including pH, chemical oxygen demand (COD), total suspended solids (TSS), total phosphates (TP) and total Kjeldahl nitrogen (TKN) using the APHA (2005) standard methods.

Bio filtration of the municipal wastewater with biochar acting as the bio adsorbent was allowed to take place over a 5 day period noting the changes in the wastewater parameters. The municipal wastewater and the treated effluent physicochemical.

The COD concentration in the municipal wastewater decreased by 90% upon treatment with bio-char. The decrease in the COD was attributed to the enhanced removal of bio contaminants as they were passed through the biochar due to the biochar’s adsorption properties as well as the high surface area of the bio char. An 89% reduction in the TSS was observed as the bio filtration process with bio char increased from one day to five days

The TKN concentration in the wastewater decreased by 64% upon treatment with bio char as a bio filter. The TP in the wastewater decreased by 78% as the bio filtration time with biochar increase. The wastewater pH changed from being alkaline to neutral during the treatment with biochar over the 5 day period

6. Use of Biochar in Textiles

In Japan and China bamboo-based biochar are already being woven into textiles to gain better thermal and breathing properties and to reduce the development of odours through sweat. The same aim is pursued through the inclusion of biochar in shoe soles and socks.