Page 127 - AJWEP-22-6

Plantain waste for lab water cleanup

The banana fruit, an agricultural commodity valued at 100-micron mesh to obtain uniform powdered material.
USD 63.6 billion, has a projected global production of For chemical activation, the pseudo-stem powder was
127.3 million tons. 22,24 India, accounting for 29% of treated with 5% acetic acid (Sigma-Aldrich, India) at
global production, is the largest producer of bananas, 60°C for 2 h to enhance its porosity and surface area
followed by China and the Philippines. Notably, 60–80 (Figure 1).
tons of plantain stems per hectare are produced during Laboratory wastewater was collected using sterile
fruit harvesting. 26,27 The plantain stem is the heaviest 5 L polyethene containers (Tarsons, India) placed
component of the banana plant, while the plantain beneath a laboratory sink during peak usage hours.
pseudo-stem is hard, fibrous, and non-edible. 7,13,28 Composite samples were obtained over a 3-h period
In India, banana trees are integral to many auspicious to account for variability in discharge. The collected
rituals, particularly in South India, resulting in the samples were immediately stored at 4°C and analyzed
widespread availability of plantain pseudo-stems. Once within 24 h.
the fruit ripens and is harvested, the pseudo-stem—no
longer functional—is chopped and often converted into 2.2. Laboratory wastewater treatment with raw
waste biomass. While plantain stems are utilized for plantain pseudo-stem (RPPS)
their therapeutic properties, the pseudo-stem is typically Chopped RPPS was added at a concentration of
discarded. 29-31 Both the pseudo-stem and the stem play 50 g/L to inert glass containers (Borosil, India), each
a crucial role in the transport of nutrients from the soil containing 1 L aliquots of the untreated laboratory
to the fruit. After harvest, the banana plant ceases to wastewater samples (S1–S5), Table 1. Each mixture
be useful, and the pseudo-stems are often burned or was left undisturbed for 24 h at room temperature (25
disposed of in rivers and lakes. 32,33 ± 2°C). No pH adjustment was performed, and natural
Due to their high cellulose content and hygroscopic pH (5.5–6.8) was retained to reflect real laboratory
properties, banana stems are effective as a porous conditions.
medium. The stem filter media is capable of After treatment, the supernatant was decanted and
34
significantly lowering chemical oxygen demand (COD), filtered, yielding first-stage filtrate, referred to as F1.
total suspended solids levels, and turbidity during This process was repeated using fresh RPPS for up
wastewater treatment processes. 35,36 Furthermore, to four treatment cycles, producing sequential filtrates
chemical pre-treatments can reduce energy usage by F2 through F4. F2–F3 are considered intermediate-
improving the fibrillation of cellulose materials, altering stage treated water, while F4 is the final-stage treated
the adsorbent surface, and boosting its capacity for ion water.
adsorption. 22,37-39 For each stage, the following parameters were
Chemicals used in laboratories are often disposed of measured: pH, TDS, turbidity, conductivity, COD,
as waste. However, improper disposal practices result in biological oxygen demand 5 days (BOD ), and
5
the discharge of water with persistence of hardness and metal concentrations (lead, cadmium, mercury,
other contaminants, leading to high oxygen demand, iron, and copper). Digital pH meters (Systronics,
heavy metal accumulation, and environmental pollution.
The high cost of wastewater treatment, especially under
resource constraints, poses a significant challenge.
This study examines the use of accessible and cost-
effective pseudo-stems as a potential adsorbent for the
purification of laboratory wastewater.

2. Materials and methods

2.1. Materials
The pseudo-stems were sourced from local vegetable
markets in Chennai, India. The raw pseudo-stems were
thoroughly cleaned with distilled water to remove dirt
and debris, and then chopped into small fragments.
These fragments were oven-dried at 120°C for 4 h, Figure 1. Photos of raw and powdered plantain
ground using a high-speed grinder, and sieved through a pseudo-stem (RPPS and PPPS)

Volume 22 Issue 6 (2025) 121 doi: 10.36922/AJWEP025110078