INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)

ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue X October 2025

Quality Assessment of Effluent from A Typical Food Processing

Industry in Port Harcourt

^a*Brume J. Egere; ^bAnthony Okhifo

^aChemical Engineering Department; University of Port Harcourt, Rivers state, Nigeria.

^bChemistry Department, Maritime University, Okerenkoko, Delta state, Nigeria.

DOI: https://dx.doi.org/10.51244/IJRSI.2025.1210000316

Received: 02 October 2025; Accepted: 08 October 2025; Published: 21 November 2025

ABSTRACT

The study investigated the quality of effluent discharge from a food industry in a Port Harcourt suburb in Rivers

State, Nigeria. The food industry is engaged in noodle pasta and vegetable oil production. The discharged

effluent is channeled to a neighboring marshland about 220m away from the factory. The purpose of this study

is to analyze the critical parameters of the food industry effluent in order to determine its pollution potential, and

also assess its possible effect on the ecosystem. Standard test methods such as the APHA (American Public

Health Association) and ASTM (American Society for Testing and Materials) methods were used to conduct the

2-

3-

2-

tests. Parameters examined were pH, conductivity, BOD, COD, SO₄, Cl^-, PO₄, Oil and grease, NO₃,

Turbidity, Fe, Zn, Pb, Cu, Cr, Cd, Ni. The data obtained from these analyses were used in assessing compliance

with regulatory limits and identifying specific pollutants requiring targeted remediation. High values of oil and

grease content were recorded both in the effluent (700.5±53.2mg/l) and in the recipient soil (3107±137mg/l)

which were extremely above the WHO/NESREA acceptable limit of 10mg/l. The high values of the oil and

grease were attributed to the absence of oil-water separator in the effluent treatment process. The mean values

of BOD (34.42±9.7mg/l) and COD (153.4±42.4mg/l) were slightly higher than the WHO/NESREA acceptable

limit of 30 and 150mg/l respectively. The control was however within the acceptable limit with recorded values

as 28.0±5.4mg/l and 110±24.6 mg/l respectively. This indicates the presence of high organic load and a proof

that the recipient environment is impacted. All the heavy metals tested in the effluent except Fe (0.77±0.25mg/l)

were below the WHO/NESREA acceptable limit of ≤0.3mg/l. The discharged effluents were generally acidic

which was indicated by low pH values with a mean of 5.09±0.6. Turbidity mean values was 40.3±8.5 NTU and

these were above the regulatory limit of 5-10NTU. The general physical state of the effluent was turbid with

whitish suspension or translucent with oily suspension on the surface. This indicated a poor treatment of the

effluent. Effluent monitoring and treatment are necessary if the environment will be spared of the dangers. This

paper, therefore, recommends that the food processing industry should effectively treat its effluents before

disposal.

INTRODUCTION

The food processing industry plays a significant role in the economy of any nation because its operations enables

the conversion of raw agricultural products into finished food items with improved nutritional, textural and shelf

values. The production activity however is not without the consequent problem of environmental pollution

(Olaniyi et. al.,2012; Omuku et. al.,2024).

Over the years, the food processing industries have generated wastes which were considered less polluting in

comparison with the oil industry effluents. The consequences of focusing on economic growth at the expense of

environmental sustainability calls for serious concern (Tommaso, 2011; Asgharnejad et. al., 2021).

The food processing sector in Nigeria is of national significance owing to the number of industries engaged in

food production activities to meet the population needs (Owalude et. al., 2021). The implication of this is the

generation of large volumes of wastes which results in environmental pollution (Tommaso, 2011). The large

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ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue X October 2025

quantity of wastewater from food processing industries largely constitutes nuisance to the environment when

discharged without compliance to regulatory standards (Ribeiro & Naval, 2021; Owalude et. al., 2021).

The food industry generates effluents which are of significant environmental concern because of the large

amount of organic content and the large volume of water used during processing (Tommaso, 2011; Joudah &

Racoviteau, 2019). Human health and the aquatic ecosystem are subjected to considerable risks due to exposure

to these discharged effluents that contain high COD, BOD and non-biodegradable pollutants (Mostafaie et al,

2021; Mangotra & Singh, 2024).

A thorough evaluation of the physiochemical characteristics of effluent is necessary in order to understand its

potential ecological impact and to develop effective treatment strategies (Haddis & Devi, 2007; Singare &

Dhabarde, 2013).

Furthermore, the presence of heavy metals and other contaminants needs to be assessed so that the overall

toxicity and potential health risks associated with the effluent discharge can be determined (Andreeva, 2021;

Owalude et al., 2021; Ahmed et. al., 2022).

The enormous volume of wastewater generated by food processing industries are often discharged without

adequate treatment thus significantly contributing to environmental degradation and public health risk (Omuku

et. al., 2024; Kato & Kansha, 2024). A thorough characterization of food industry effluents is necessary in order

to develop a sustainable water management practice and mitigate effluent ecological footprint (Asgharnejad et.

al.,2021).

The negligence or limited attention to waste management and control by the food industry has left much to be

desired in the proper discharge of the effluent generated (Nkwocha et. al., 2013).

The food processing industry located in a Port Harcourt suburb is involved in vegetable oil and pasta noodle

production. The food industry generates wastes which are majorly in solid and liquid forms. The solid wastes

are generated from the flour mixing unit obtained as spills (crumbs and over burnt noodles) from the noodle

frying section, wrapping papers from the packaging unit and off specs (over and under fried noodles) from the

frying unit. However, the off specs are used as animal feed while the dry solid wastes like flour spills and waste

packaging materials are disposed of with the other domestic waste into municipal garbage systems (Bhatia,

2005).

Sources of waste water or effluent within the facility include cleaning of vegetable oil tanks, greasy floor

washings and cleaning of dough mixers. Also, machine repair floors also contribute to the effluents after

washings. (Noukeu & Ekodeck, 2016). OSI (2019) reported that one of the major problem food processing

industries encounter is the presence of spent oil in their wastewater stream. This oil in water usually come from

the leftover or spent oils used in processing the foods. The used oil is usually drained and re-used but some are

washed and flushed out during housekeeping and maintenance. This liquid effluent when discharged from the

industry without adequate treatment becomes a problem in the environment (OSI, 2019).

Government policies on environmental issues must be clearly stated if measures designed to protect the

environment will be effective. This is very important because no amount of technological (or scientific device)

or design can effectively protect the environment without the legal system to sustain them (Okorodudu & Fubara,

1988). The attention of the Nigeria government was first drawn to environmental issue after the incident of toxic

waste dump at Koko, Delta in 1987. Following the incident, the Federal environmental protection agency

(FEPA) was created. Its mandate was to formulate policies and coordinate activities that manage environmental

issues. In 1999, FEPA was restructured to become the Federal ministry of Environment (FMENV). FMENV

lacked powers to enforce these laws. This led to the creation of the National environmental standards and

regulation enforcement agency (NESREA) in 2007. The agency is saddled with the responsibility of monitoring

industries and enforcing environmental laws in the country (Ogbodo & Gozie, 2009). The key environmental

challenges associated with the food processing industries are the management of waste water and solid wastes

generated in the various stages. The absence of an efficient effluent monitoring system especially in most food

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ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue X October 2025

processing industry especially in the developing countries has have left much to be desired with respect to

pollution mitigation and control (Nkwocha et al, 2013)

Alamm et al (2007) reported that waste water from food industries studied showed high iron concentrations as

well as high BODs. Bhatia (2005) observed that, though the food industries are not as polluting as some sectors

such as metal, leather, oil and gas industries, they also contribute to air, water and soil pollution through the

emission of particulate matter and unpleasant odour, discharge of liquid effluent with high organic content and

large quantities of sludge. However, waste water is the primary area of concern in the food processing industry.

If the effluents are contaminated with toxic metals, it will adversely affect human health as well as flora and

fauna.

Environmental problems have increased in geometric proportion over the last three decades, with improper and

inadequate management practices being largely responsible for the gross pollution of the aquatic environment

(Osibanjo and Adie, 2007). Amabye (2013) noted that environmental pollution is caused to a large extent by

aqueous discharges produced during industrial manufacturing processes which includes the food industry. In

developing countries like Nigeria, pollution has continued to generate unpleasant consequences in health and

economic development. The waste generated from food production can lead to surface and ground water

contamination and as well stress the terrestrial wet land ecosystem if not adequately managed because of the

presence of heavy metals, oil and grease in water and sludge discharged to land.

Most of the organic substances from industrial sources found in water can cause death or reproductive defects

in aquatic fauna. The harmful substances discharged into aquatic habitat accumulate in animal tissues, sediment

and find their way into drinking water supplies thus becoming a long-term health risk to humans (Alamm et al,

2007).

Although industries are expected to treat their effluents prior to discharge, most industries fail to meet the

required standard for disposal due to lack of adequate treatment technology, infrastructure and selfish drive to

make profit at the expense of best practices. This has resulted in the buildup of deleterious materials/ substances

in the environment upon discharge. Proper treatment and monitoring of effluent are key to human and

environmental survival (Bhatia, 2005).

The food industry operators take advantage of the fact that the pollution from their industry is often overlooked

because of the focus on pollution from the oil and gas industry. This has made some of the operators of the food

industry to carry out their operations and discharge effluents without treatment. This study thus assessed the

quality of discharged effluent from a typical food industry on a recipient environment and it is hoped that this

will spur further studies related to this study. In a bid to comply with statutory requirement for pollution control

in Nigeria, the industry under study discharge its effluent on land rather than on surface water. Verbal inquiries

revealed that this food industry initially channeled their effluent directly into the nearby river but had to stop due

to community agitations against the practice which made the management resort to discharge on land.

MATERIALS AND METHODS

Sample Collection

The effluent from a noodle pasta production factory in Port Harcourt, South-south, Nigeria was collected outside

the factory. The effluent / waste water was monitored for three months between April and June (twice a month).

Effluents were discharged into a dug-out channel leading to neighboring marshland. Samples were collected

from three points along the channel. The grab sample method was used for collection of the sample. Clean wide

necked 1 litre sample bottles were used. These were properly labeled indicating sample name and date of

collection. The field sampling and data acquisition were carried out using the following among others; glass

sampling bottles, plastic sampling bottles, Hanna pH meter, conductivity, and turbidity field test meters.

The effluent waste water was sampled twice monthly for three months (April to June, 2022) while the sediment

from recipient soil was sampled once each month. Effluent samples were obtained from three points along an

approximately 220 metres stretch of a 2m wide by 1.5m deep dug- out trench channel created for effluent

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INTERNATIONAL JOURNAL OF RESEARCH AND SCIENTIFIC INNOVATION (IJRSI)

ISSN No. 2321-2705 | DOI: 10.51244/IJRSI |Volume XII Issue X October 2025

discharged. The sampling point were designated as follows; SPT (source point), which is nearest to where

effluent leaves the factory; MPT (midpoint), the point approximately equidistant between the marsh land and

effluent source while the EPT (end point) is the marshland area where the effluent largely accumulates and

spreads. The control sample was collected from an open field area within a university campus 3 kilometres away

from the sampling location. The soil and accumulated rainfall water were sampled as control. In sample handling

and collection, wide necked sample bottles were used to collect samples. The sample bottles were thoroughly

washed using mild detergent and water. Glassware brush was used to remove oil, dirt or dust that might have

adhered to the walls of the container. Samples for oil and grease test were collected using glass bottles. The

sample bottles were filled to the mouth to ensure no air space was left in order to prevent oxidation reaction.

Testing Methods

2-

3-

Standard methods recommended by APHA and ASTM were used to determine COD, BOD₅, SO ₄, Cl^-,PO₄,

NO₃^2-(ASTM, 1995). pH was determined using the HANNA digital pH meter. Metals were determined using

Atomic Absorption spectrophotometer (AAnalyst 200). SO₄,PO₄and NO₃were determined using the

thermo spectronic genesys 20 spectrometer.

2-

3-

2-

Determination of chlorides content:

Standard solution of NaCl was prepared by dissolving 8.24g of oven dried NaCl in distilled water and made up

to 500cm³. 50cm³of the resulting solution was diluted to 1000cm³. Each 1cm³of the new solution contained

0.500mg Cl^-. Standard AgNO₃solution was also prepared by dissolving 2.396g AgNO₃in 1 litre of distilled

water. The resulting solution is equivalent to 0.500mg Cl^-. This was standardized against standard NaCl solution.

The potassium chromate indicator used was prepared by dissolving 8g of K₂CrO₄in 100cm³distilled water.

10cm³of the sample was transferred into a beaker. Few drops of K₂CrO₄indicator added. This was titrated

against AgNO₃solution. The appearance of a red brick color indicated the end point.

AgNO3 titrated 1000 0.5

Chloride content (mg/l) =

……………….(1)

Determination of chemical oxygen demand (COD) by dichromate method:

Chemical oxygen demand (COD) of each of the effluent samples was determined using the dichromate. 10cm³

of the sample was poured into an Erlenmeyer flask. 1cm³20% H₂SO₄and 1cm³KMnO₄was added to the sample

including blank. These were incubated at 27⁰C for 4 hours. The change in colour was monitored and noted and

at such instance, 1cm³more of reagent was added taking note of such addition. After four hours, 10% KI was

added to the sample and this was titrated with 0.0125N Na₂SiO₃using starch indicator. The results for blank and

sample readings were recorded. 0.0125N KMnO4 was prepared by first diluting 125cm³of 0.1N KMnO₄

solution, with distilled water to make up to 1000cm³of 0.0125N Na₂SiO₃solution, and making up to 1000cm³

distilled water. 20% v/v H2SO4 was prepared by dissolving 20cm³H₂SO₄Analar in 100cm³distilled water. 1%

starch solution was prepared by dissolving 1g of solid starch in 100cm³. 10% KI was prepared by dissolving

10% KI in distilled water. Hence, in calculation;

For 1cm³,

)

COD(mg/l)= ⁽

……………………(2)

−

1000

Determination of Biochemical Oxygen Demand (BOD):

The BODs of samples were determined by winkler method. Manganese sulphate solution was prepared by

dissolving 40.0g MnSO₄.H₂O in 25cm³of distilled water in a beaker. This was transferred to a 100cm³

volumetric flask and made up to mark. Alkaline potassium iodide reagent was prepared by dissolving 70g KOH

and 15g KI in 75cm³distilled water. The solution was cooled and made up to 100cm³. Starch solution was

prepared by adding a pinch of soluble starch to about 20cm³water; the solution was boiled and cooled. 0.025N

sodium thiosulphate, Na₂S₂O₃.5H₂0 solution was prepared by diluting 12.5cm³of stock solution and diluting to

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500cm³with distilled water. 0.613g K₂CrO₇(dried at 25⁰C) was dissolved in 500cm³distilled water.

Standardization of K₂CrO₇was done by titrating against 0.025N Na₂S₂O₃.5H₂0. Using a pipette, 10cm³sample

was transferred into the amber bottle and made up with distilled water. A clear bottle was also filled with distilled

water only. The contents of both bottles were then transferred into a conical flask. From the resulting mixture in

the flask, both bottles were refilled again. Using a pipette, 0.5N MnSO₄solution of 0.5N KOH and 0.5N KI

solution were added into the clear bottles and amber bottles. Concentrated H₂SO₄was added and 2.5cm³portion

was taken. Starch indicator was added and this was titrated against 0.025N Na₂S₂O₃.5H₂0. A Blue Black colour

change indicated the end point. The result obtained represented the initial dissolved oxygen value; D.O₁. The

amber bottle sample was kept in a dark place and incubated at room temperature for five days after which titration

was repeated as above to determine D.O₂. Hence,

BOD (mg/l) =^{(D.O1−D.O2)}………………………………………….…(3)

Where D.O₁= D.O value of diluted sample 15 minutes after dilution. D.O₂= D.O value of diluted sample after

five days incubation.

P = Fraction of sample expressed as (

) …………..(4)

Determination of sulphate concentration:

Standard solution was prepared by pipetting 25cm³of the sulphate stock solution and transferring into a 500cm³

volumetric flask. Sulphate stock solution was prepared by weighing 453.4mg K₂SO₄and drying at 105⁰C. serial

dilution volume was determined using the dilution equation,

C₁V₁=C₂V₂…………………………………………(5)

10cm³of sample was transferred into a test tube and a pinch amount of BaCl₂was added. This was allowed to

stand for some time until turbid appearance was observed. Blank was determined using distilled water in a

cuvette. 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0cm³of the standard solution were respectively transferred into 50cm³

volumetric flasks and were made up to mark. The absorbances of the concentrations were determined and a

graph of concentration against absorbance was plotted. The value obtained as the slope was used to determine

corresponding slopes of concentration. Thus, sulphate concentration (mg/l)= 114.578 x absorbance value

obtained.

Determination of phosphate concentration:

The phosphate concentration in water sample was determined using a mixed reagent comprising of ammonium

molybdate , ascorbic, potassium antimony tartrate and hydrogen tetraoxosulphate VI acid. Ammonium

molybdate, (NH₄)₆Mo.4H₂0 solution was prepared by dissolving 4g in 100cm³distilled water. Ascorbic acid

was prepared by dissolving 1.76g in 100cm³potassium antimony tartrate, K(SbO)C₄H₄.¹H₂O solution was

2

prepared by dissolving 0.28g in 100cm³distilled water. 5N H₂SO₄was prepared by measuring 140cm³conc.

H₂SO₄and made up to 1 litre in a volumetric flask. A combined reagent was prepared by mixing 5cm³of 5N

H₂SO₄, 0.5cm³of potassium antimony tartrate, 1.5cm³of ammonium molybdate solution, and 3cm³of ascorbic

acid in the order listed. 0.8cm³of the combined reagent was added to 5cm³of sample in a test tube. This was

observed for thirty minutes, for colour change; which indicate presence of phosphates. Phosphates concentration

was determined using the filter photo colorimeter. Absorbance was measured at 880nm using the combined

reagent with distilled water as blank or reference solution. 5cm³of distilled water was used for the reference

instead of 5cm³of the sample. The absorbance of the sample was then determined (APHA, 1985).

Calculation,

∑P = Absorbance X 10……………………………… ….(6)

Standard phosphate solution was prepared by dissolving 219.5mg KH₂PO₄and diluted to 1000cm³,

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1.00cm³= 50.0µg PO₄= 0.05mg PO₄………………………(7)

Then using the dilution equation,

C₁V₁= C₂V₂

Where C₁= concentration of standard phosphate solution= 0.05mg/l

V₁= volume of standard phosphate solution required= ?

C₂= Concentration of diluted phosphate solution=0.0001mg/l

V₂= (0.0001 x 50)/0.05 =0.1cm³,

To obtain a 0.001mg/l phosphate solution, 0.1cm³of the standard solution was diluted to 50cm³in a volumetric

flask. Series of concentration were obtained following the same procedure above. Thus, 0.002, 0.003, 0.004,

0.005, 0.006mg/l PO₄solution were prepared. Their corresponding absorbance was determined using the filter

photometer at 470nm. The curve was obtained by plotting concentration against absorbance. The slope obtained

gave the multiplying factor used to determine PO₄concentration of sample from absorbance (APHA, 1985).

Determination of nitrate concentration:

25% brucine reagent was prepared by dissolving 2.5g of brucine sulphate in 100cm³glacial acetic acid. The

reagent was stored in the dark. Care was taken in handling the reagent due to its toxicity. 50mg/l of standard

NO₃solution was prepared by dissolving 1.1805g of KNO₃in 500cm³of the extracting solution. 0.5cm³

chloroform was added as a a preservative. From the stock solution, various nitrate standard: 0.001, 0.003, 0.005,

0.007, and 0.010 were prepared. 0.5cm³of the brucine reagent and 0.2cm³conc. H₂SO₄was added to 10cm³of

the sample in a beaker. The mixture was then heated on a heating block until a colour change was observed. This

was then air-cooled for 15min. and absorbance was measured using the genesis 20 spectrometer.

Calculation,

∑N = Absorbance x 1.6 …………………………………………………………….(8)

Determination of heavy metal concentration:

Heavy metal concentrations of effluents and sediments were determined only after sample digestion have been

carried out. For effluent sample, 50cm³sample was vaporized. 5cm³perchloric acid and 5cm³nitric acid was

added.. these were now transferred into sample bottles in preparation for analyses. The atomic absorption

spectrophotometer (AAS), perkin elmer AAnalyst 200 was used to analyse the samples. For sediment samples,

the samples were air-dried and then heated in an oven at 100⁰C. This was then ground and then sieved with a 1

millipore sieve to remove coarse particles. 2.0g of the fine sample was weighed. Perchloric acid and concentrated

HNO₃in ratio 1:3 was added. In a 100cm³beaker, the mixture was heated for 15 minutes until gases evolved.

50cm³of distilled water was then added. This was finally transferred into sample bottle for storage preparation

for analysis. Analysis was carried out using Perkin Elmer Aanalyst 200 AAS

Determination of turbidity:

50cm³of effluent sample was transferred into the turbidimeter tube. This was shaken to disperse any solid and

left to stand until all air bubbles have dispersed. The sample was decanted into the cuvettte of the turbidimeter

and the cuvette was transferred into the hack 310 turbidimeter. Turbidity was read directly from the scale and

recorded in nephelometric turbidity unit (NTU). (ASTM,1995).

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RESULTS

The data on tables 1 and 2 below are the results obtained for the food effluent and the recipient soil. These are

presented as follows;

Table 1: Physicochemical characteristics of food industry effluent and regulatory limits

SPT

MPT

EPT

OVERALL

MEAN

WHO/

PARAMETER MEAN

MEAN

CONTROL NESREA

pH

5.05±0.75

69.5±18.3

431.2±11.5

26.8±4.5

159±5.1

4.95±0.76

71.0±31.3

516±24.3

32.5±4.47

151.8±5.8

81.3±4.7

103.5±7.4

36.5±6.5

57±6

5.27±0.49

80.0±26

1154±77.0

43.9±10.3

149.5±6.8

93.2±6.5

103.5±7.1

39.5±6.60

63±3

5.09±0.60

73.5±22.9

6.05±0.25

17.5±5.2

6.0-9.0

≤1000

10-20

≤30

EC, µs/cm

Oil & grease

BOD,mg/l

COD, mg/l

700.5±53.2 1.58±0.4

34.42±4.4

153.4±9.7

91.9±5.5

97.06±5.7

40.3±8.5

51.3±5.7

0.77±0.25

2.8±0.54

11.0±2.6

8.26±1.97

8.0±2.3

≤150

≤500

≤600

≤5-10

≤30

Sulphates,mg/l 101.2±5.8

Chlorides,mg/l 84.2±4.7

Turbidity,NTU 44.9±12.1

21.0±4.3

16.5±1.8

0.19±0.03

0.05±0.01

TOC, mg/l

Fe, mg/l

Zn. mg/l

Pb, mg/l

Cu, mg/l

Cr, mg/l

Cd, mg/l

Ni, mg/l

34±8

0.67±0.21

0.077±0.04

0.05±0.002

0.89±0.18

1.17±0.08

≤1.0

0.087±0.013 0.153±0.014 0.08±0.04

≤1.0

0.053±0.0067 0.053±0.006 0.05±0.002 0.001±0.0

≤0.1

0.067±0.007 0.077±0.0081 0.06±0.002 0.072±0.008 0.06±0.01

≤1.0

0.06±0.00

0.01±0.00

0.063±0.01

0.06±0.00

0.01±0.00

0.06±0.00

0.01±0.00

0.06±0.00

0.01±0.00

0.01±0.001 ≤0.1

0.001±0.0

≤0.01

≤0.2

0.087±0.011 0.067±0.003 0.075±0.013 0.03±0.01

The data on Table 1 above represent results from tests carried out on effluent samples collected from each

designated sampling points (i.e SPT, MPT, EPT) along the dug-out channel. The average at each point is

presented and the overall mean was determined from the values obtained at the three points for each parameter.

The pH values of the effluent at SPT, MPT, EPT were 5.05, 4.95, 5.27 respectively giving a mean of 5.09±0.60.

Electrical conductivity (EC), values at SPT, MPT, EPT were 69.5, 71.0, 80.0µs/cm respectively with a mean of

73.5±22.9µs/cm. Oil & grease values SPT, MPT, EPT were 431.2, 516, 1154mg/l with a mean of 700.5±53.2.

BOD values at SPT, MPT, EPT were 26.8, 32.5, 43.9mg/l giving a mean of 34.42±9.7mg/l. COD values at SPT,

MPT, EPT were respectively 159, 151.8, 149.5mg/l with a mean of 153.4±4.4mg/l. sulphates concentration

values at SPT, MPT, EPT were 101.2, 81.3, 93.2mg/l respectively giving a mean of 91.9±5.5mg/l. Chlorides

concentration values at SPT, MPT, EPT were respectively 84.2, 103.5, 103.5mg/l and had a mean of

97.06±5.7mg/l. Turbidity values at SPT, MPT, EPT were 44.9, 36.5, 39.5NTU respectively with a mean of

40.3±8.5NTU. TOC values at SPT, MPT, EPT were 34, 57, 63mg/l with a mean of 16.5±1.8mg/l.

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Fe values at SPT, MPT, EPT were 0.67, 0.89, 1.17mg/l with a mean of 0.77±0.25mg/l. Zn values at SPT, MPT,

EPT were 0.077, 0.087, 0.153mg/l with a mean of 0.08±0.04mg/l. Pb values at SPT, MPT, EPT were 0.05, 0.053,

0.053mg/l with a mean 0.05±0.002mg/l. Cu values at SPT, MPT, EPT were0.067, 0.077, 0.06mg/l respectively

with a mean of 0.072±0.008mg/l. Cr values at SPT, MPT, EPT all recorded 0.06mg/l giving the mean as the

same value. Cd values at SPT, MPT, EPT were 0.01mg/l at all point giving a mean of the same value. Ni values

at SPT, MPT, EPT 0.063, 0.087, 0.067mg/l giving a mean of 0.075±0.013mg/l.

Table 2: Physicochemical Characteristics of the recipient soil over a Three- month period

SPT

MPT

EPT

OVERALL

MEAN

WHO/

PARAMETER MEAN

MEAN

CONTROL NESREA

Ph

5.98±0.21

6.44±0.14 6.17±0.09 6.20±0.15

6.63±0.09

9.0±0.6

6.0-8.5

1˂4000

1˂50

EC, µS/cm

88.5±17.67 173.5±0.71 140.5±9.19 134.2±8.8

Oil& Gr, mg/kg 3854±122

3180±136 2288±143 3107±137

126±14

Sulphates, mg/l 60.55±2.94 124.6±6.6 68.9±2.8

Chlorides,

84.67±4.11 8.26±0.64

˂500

mg/kg

410±41.4

31.4±0.87

14.4±1.5

2.5±0.21

526±54

31.6±2.7

10.6±0.7

2.3±0.4

538.5±44

33.6±2.0

10.8±0.9

3.5±0.4

491.5±49

32.2±0.63

11.9±1.3

2.77±0.34

20±1.6

˂250

˂100

˂50

∑P, mg/kg

∑N, mg/kg

TOC,%

16.3±0.13

7.0±0.1

1.24±0.4

NA

Fe, mg/kg

Zn, mg/kg

Pb, mg/kg

Cu, mg/kg

Cr, mg/kg

Cd, mg/kg

Ni, mg/kg

13.11±2.46 36.03±0.42 20.5±1.27 23.2±0.76

13.16±0.36 ˂50

1.02±0.01 ˂140

0.33±0.011 ˂50

4.49±0.19

1.3±0.00

11.8±1.4

0.56±0.0

0.1±0.0

4.12±0.21 3.65±0.21 4.09±0.20

1.63±0.177 1.76±0.176 1.56±0.21

19.9±0.5

0.6±0.00

14.6±1.8

0.65±0.0

15.4±1.7

0.6±0.0

4.4±0.12

0.03±0.0

0.02±0.0

˂100

˂10

0.21±0.28 0.11±0.013 0.14±0.03

˂1.0

˂50

1.15±0.11

3.85±0.78 4.45±0.16 3.15±0.056 0.01±0.00

The pH values of the recipient soil at SPT, MPT, EPT were 5.98, 6.44, 6.17 respectively giving a mean of

6.20±0.15. Electrical conductivity (EC), values at SPT, MPT, EPT were 88.5, 173.5, 140µs/cm respectively with

a mean of 134.2±8.8µs/cm. Oil & grease values SPT, MPT, EPT were 3854, 3180, 2288mg/kg with a mean of

3107±137mg/kg. Sulphates concentration values at SPT, MPT, EPT were 60.55, 124.6, 68.9mg/kg respectively

giving a mean of 84.67±14.6mg/kg. Chloride concentration values at SPT, MPT, EPT were respectively 410,

526, 538.5mg/kg and had a mean of 491.5±49mg/kg. Total Phosphates (∑N) values at SPT, MPT, EPT were

31.4, 31.6, 33.6mg/kg respectively with a mean of 32.2±0.63mg/kg. Total nitrates (∑N) at SPT, MPT, EPT were

14.4, 10.6, 10.8mg/kg with a mean value of 11.9±1.3mg/kg. TOC values at SPT, MPT, EPT were 10.5, 10.3,

13.5% with a mean 11.2±3.4%.

Fe values at SPT, MPT, EPT were 13.11, 36.03, 20.5mg/kg with a mean of 23.2±0.76mg/kg. Zn values at SPT,

MPT, EPT were 4.49, 4.12, 3.65mg/kg with a mean of 4.09±0.20mg/kg. Pb values at SPT, MPT, EPT were 1.3,

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1.63, 1.76mg/kg with a mean 1.56±0.21mg/kg. Cu values at SPT, MPT, EPT were 1.18, 1.99, 1.46mg/l

respectively with a mean of 1.54±0.17mg/kg. Cr values at SPT, MPT, EPT all recorded 0.56, 0.6, 0.65mg/kg

giving the mean value of 0.60mg/kg. Cd values at SPT, MPT, EPT were 0.10, 0.21, 0.11 mg/kg with a mean

value 0.14±0.03mg/kg. Ni values at SPT, MPT, EPT 1.15, 3.85, 4.45mg/kg giving a mean of 3.15±0.056mg/kg.

DISCUSSION

The tables of results are analyzed in two sections; the effluent and the recipient soil. These are discussed as

follows;

Effluent

pH

From the data in Table 1, the pH of the food processing industry effluent ranged from 4.95 to 5.27and is below

the WHO/NESREA permissible limits which is indicative of acidity. The ascidity of the effluent may be due to

the use of acid, production of acidic byproduct. Also, it could be due to industrial emissions. The chemical

changes in water influences its pH. It is significant that none of the effluent pH fell within the regulatory limit

of 6-9. However, the control pH (6.05) is within the permissible limit. Qasim and Mane (2013) reported pH of

7.10, 5.64 and 6.25 for the effluents from dairy, sweet-snack and ice-cream processing industries respectively.

Siyanbola et al (2011) investigated the effluent from five different food industries and reported pH of 3.03, 1.36,

1.61, 1.71 and 4.91. The pH of the effluent under study was more acidic than pH values reported by Qasim and

Mane (2013) but less acidic than that reported by Siyanbola et al (2011). Nwosu et al (2014) reported a pH range

of 2.91-5.62 for three food processing industries. These pH results obtained showed that the effluents were not

properly treated and also indicated a possible poor in house treatment of effluents by the industry. The mean pH

of the effluent (5.09±0.60) is below the range of 6.0-9.0. This is indicating potential environmental concerns.

This may suggest that the neutralization process was not carried out or poorly carried out on the effluent. Emodi

(2020) analyzed effluents from an industrial area in Enugu and obtained pH as 8.6. This is higher than the pH of

the effluent under study and within the limit. Also, Abrha & Chen (2017) analyzed effluents from different

Beverage Industry in Ethiopia and recorded pH in the range 5.21-12.37. The effluents from the beverage industry

were either acidic or alkaline depending on the composition of each food industry effluent. The food industry

effluent was on the acidic range. This acidic pH values observed may potentially impact biological treatment

efficiency thus necessitating neutralization steps prior to further treatment processes.

Electrical Conductivity

Electrical conductivity measures the ease with which a solution allows electric charge or heat to pass through

it. The presence of ionizable solutes in effluent contributes to its conductivity (Bhatia, 2005). The conductivity

of control sample (17.5±5.2, µS/cm) was lower than the mean conductivity value of the effluent samples

(73.5±22.9µS/cm) indicating the presence of ionizable salts in the discharged wastewater. High electrical

conductivity value is an indication of contamination and may lead to corrosion of equipment and pipes. This

might be from the dissolved salts washed off with the effluents. The highest value obtained for conductivity was

80±26us/cm at EPT while the lowest value of 69.5±18.3µs/cm was recorded at SPT. The conductivity values

were however generally below the permissible limit of 1000µs/cm.

Oil & Grease

The Oil & Grease values were significantly high, having a mean of 700.5± mg/l, which far exceeds the ≤10 mg/l

regulatory limit. The value suggests a considerable organic load presence. This is likely due to grease trap and

oil skimmer overload due to high oil and grease content in raw effluent. There was an insignificant presence of

oil and grease in the control having a value of 1.58±mg/l. The elevated levels of oil and grease, as depicted in

the effluent result, not only contribute to the high organic load of the effluent but also present specific challenges

in wastewater treatment due to their immiscibility and tendency to foul treatment equipment. This necessitates

a comprehensive treatment approach that includes effective pre-treatment stages to remove these components.

Oil-water skimmers, separator or centrifuge should be effectively used to remove floating oil mass. Also,

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coagulants should be added to the effluent to break emulsions and facilitate removal of oil. Biological treatment

using microorganism could be employed to biodegrade oil and grease. Finally, advanced tertiary treatments such

as membrane filtration could also be employed to ensure compliance with stringent environmental regulations.

BOD & COD

Biochemical oxygen demand (BOD) measures the amount of dissolved oxygen required by aerobic organisms

for the decomposition of organic matter present in a given aquatic medium (Bartram, 2005). It defines the extent

of pollution of the water while chemical oxygen demand (COD) measures all chemically oxidizable matter

present in water. The mean BOD value was 34.42±4.7 mg/l which is slightly above the ≤30 mg/l regulatory

limit. This indicated that there is a high demand for oxygen by microorganisms to break down organic matter in

the effluent. The control recorded BOD value of 18±3.4mg/l. The COD recorded mean value of 153±9.7mg/l

and the control COD value was 54.6±4.6mg/l. Effluent samples from two top Nigerian food industries (biscuit

and beverage production) were investigated, the biscuit industry recorded higher BOD and COD values than the

beverage industry effluent (Osho et. al, 2010). Noukeu et. al. (2016) characterized the effluent from food

processing industries and observed that biscuit factory recorded a BOD value of 1126±27.6mg/l. This value was

far higher than the effluent of the food industry under study. There is the need to evaluate the adsorption capacity

of various treatment methods for these pollutants, as demonstrated in studies where significant reductions in

BOD and COD were achieved (Kholif et al, 2023). This highlights the effectiveness of such approaches in

enhancing water quality. Specifically, orthophosphoric acid-modified rice husk activated carbon has shown

substantial efficacy in treating fast-food wastewater, leading to significant reductions in BOD and COD, thereby

minimizing environmental impact (Omuku et al., 2024). The high levels of organic matter, particularly reflected

in the COD and BOD values, suggest a possible pollution potential thus this necessitates using robust wastewater

treatment strategies before discharge. The BOD can be improved through anaerobic digestion which would aid

the breakdown of organic matter. To improve COD, membrane filtration or absorption can be used including

processes like flocculation and coagulation.

Turbidity

The turbidity of water describes the extent of non-clarity of the water due the presence of particles not readily

visible to the naked eye. It attests to the quality of water. Turbidity value for the effluent ranged from 36.5-44.9

NTU. The turbidity value ranged from 36.5 to 44.9NTU with a mean value of 40.3±8.5NTU. The effluent

turbidity value which is above the ≤5-10 NTU standard limit suggest a high concentration of suspended solids.

This can affect penetration of light thereby negatively affecting aquatic plants. The effluent can be treated by

physical processes such as filtration, centrifugation and sedimentation. Chemical treatment process such as

flocculation and coagulation can also be applied to reduce turbidity by removing suspended solids. Also,

activated sludge and trickling filters can be used to biologically treat the wastewater. Natural coagulants obtained

from biomass have shown effectiveness in the reduction of turbidity in wastewater.

Total Organic Carbon (TOC)

Total organic carbon (TOC) is the measure of the organic molecules or contaminants present in a given sample

of water. TOC value helps to assess if the water is fit for use in a desired process. All water contain carbon to

differing extent. The permissible level for TOC is 30mg/l. The mean value (51.3±5.7mg/l) is above the ≤30 mg/l

standard and is above the control value of 6.05±1.8mg/l. This indicates a moderate level of organic matter. When

TOC level is high, it can lead to oxygen level depletion in water bodies. Thus, there is need to further treat the

effluent to reduce TOC level to comply with regulatory standards. The organic compounds can be removed

through activated carbon adsorption. Also, advanced oxidation such as the use of Fenton’s reagent, Ultra violet

and ozone can help oxidize organic compounds. Biological treatment can be applied in which the organic matter

would be biodegraded using aerobic or anaerobic processes.

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Sulphates

Sulphates are the salts of sulphuric acid. They are inorganic ions that are found in nature and can be synthesized

for industry. Sulphates are surfactants that enables surface tension of water to break up, hence, their use as active

ingredients in the production of cleaning agents.

Sulphate concentration in the effluent were generally below the limit with the sixth week effluent recording

highest value of 101.2±5.8mg/l at SPT and 81.3±4.7mg/l being the lowest value obtained at MPT. The mean

TOC value was 91.9±5.5mg/l. This value is below the regulatory limit of ≤500mg/l. The control recorded

8.26±1.97mg/l which is far less than the value of the mean sulphate concentration of the effluent. This suggests

that the effluent would be less harmful in th environment due to low sulphate concentration.

Chlorides

Chlorides are salts resulting from the reaction of chlorine gas and a metal. Some common chlorides are sodium

chloride and magnesium chlorides. Chlorides are harmless at low concentration but at high concentration they

are harmful to plants if used for irrigation or any agricultural purpose. Chloride concentration measured were all

below acceptable limits of ≤600mg/l. The highest value for chloride concentration were recorded at MPT and

SPT with values of 103.5±7.4mg/l and 103.5±7.1mg/l respectively. High chlorides content in effluent affects

aquatic life and water quality. It can also be a major source of corrosion and equipment damage.

Heavy Metals

Heavy metals are naturally occurring elements with densities above 5g/cm³. They possess high atomic weight

and are toxic to plant, animals and humans even at low concentration. They are non-biodegradable and are thus

persistent in the environment. They are known to bioaccumulate in living systems causing irreparable damage.

The mean values of Iron, Zinc, Lead, Copper, Chromium, Cadmium, and Nickel were 0.77±0.25, 0.08±0.04,

0.05±0.02, 0.072±0.008, 0.06±0.00, 0.01±0.00, 0.075±0.013mg/l and they are within their respective

permissible limits. However, their values are higher than the control values. High concentration of toxic metals

result to accumulation in organisms, causing stunted growth, reproductive damage and even death. Discharge of

untreated effluent with high heavy metal concentration into surface waters contaminate the water and exposure

to this lead to bioaccumulation in aquatic organisms and may end up being consumed by humans leading to

organ failure, cancer or neurological disorder. The environmental concerns of some specific toxic metals are as

follows; chromium and nickel are carcinogenic and toxic while lead and cadmium are carcinogenic, nephrotoxic

and neurotoxic. The effluent showed minimal presence of the toxic metals indicating a possible effectiveness in

treatment

Recipient Soil

The data in Table 2, showing the physicochemical characteristics of the recipient soil, also indicates significant

impact from the effluent:

pH

pH responds to any change in chemically composition of the aqueous solution. The mean pH of the soil

(6.20±0.15) is within the acceptable range of 6.0-8.5. the control pH was 6.63±0.09. It is interesting to note that

the pH of the recipient soil improved and was within the standard limit. This could be due to the buffering

capacity of the soil which enables it to resist changes in pH. Soil minerals can react with acidic compounds

giving rise to improved pH. Microbial activity can result to break down of organic matter which can buffer pH

changes.

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Conductivity

Conductivity is the measure of the ability of a medium to conduct electricity and it is related to the presence of

ions in solution. Conductivity of soil recorded highest value of 140.5±9.19 EPT while the lowest value for soil

conductivity was 88.5±7.67µs/cm. The conductivity values were higher than effluent values. The NESREA

permissible limit for conductivity in sediment is 4000 µs/cm. Conductivity in sediment is definitely due to many

factors making it not-assessable. However, setting limit ensures soil health and plant growth are not affected by

excessive salinity.

Oil and Grease

Oil and grease include the fats, oils, waxes and other related constituents found mostly in wastewater. It can also

be termed as any substance present in wastewater and recoverable by solubility in solvent. Oil and grease had

its highest value of 3854±122mg/kg at SPT while the lowest value is 2288±143mg/kg. the overall mean oil and

grease value was 3107±137mg/kg. The discharge of oily wastewater on land is a major source of land pollution.

The aerobic condition of the soil is affected due to reduction in the oxygen content of the soil. This unusually

high value for oil and grease suggested a discharge of wholly untreated effluent containing accumulated fats,

grease and oil. However, none of the values obtained fell within the regulatory limit of 30mg/l. the control

sample had a value of 126±14mg/kg. The non-compliance of the effluent samples confirmed that the effluent

was not treated. The mean concentration of Oil & Grease in the recipient soil (3107± mg/kg) is exceedingly

higher than the control (126± mg/kg) and the WHO/NESREA limit (˂50 mg/kg). This indicates severe

contamination of the soil with organic pollutants from the effluent and a result of accumulation over the period.

TOC

The mean TOC (2.77±0.34%) is notably higher than the control (1.24±0.4%). This is above the 1-2% limit

range for agricultural soils. There is no set limit for TOC in soils. However, the value obtained points to

organic matter accumulation. High TOC value range from 2-5%.

Sulphates

Much of the Sulphur containing fuels end up in soils as sulphates which react with soil water to form sulphuric

acid. Most sulphates result from the oxidation of sulphuric acid (Bhatia, 2005). The range value of sulphate

concentration in sediment was 60.55±2.94 to 124.6±6.6mg/kg which is however low when compared to

permissible limit of less than 500mg/kg. Soils get enormous quantities of waste products each year which mainly

include sewage effluent and unlimited varieties of industrial liquid wastes. The control sample for soil was

significantly less (8.26mg/kg). It can also be observed that the sulphate values in soil were slightly lower in

effluent. This could indicate the reason for the more acidic pH of effluent compared to the soil.

Chlorides

The mean chloride level (491.5± mg/kg) is significantly higher than the control (20 mg/kg) and exceeds the

WHO/NESREA limit (˂250 mg/kg). The Chlorides concentration measured were generally below the regulatory

limits of 600mg/kg. The highest value for chloride concentration was 538.5±44mg/kg recorded at EPT while the

lowest value was 410mg/kg recorded at SPT. The values for chlorides concentration obtained for sediment were

far above values obtained for effluent samples.

Phosphates

The mean phosphorus content (32.2±0.63 mg/kg) is higher than the control (16.3± 0.13mg/kg), although, within

the WHO/NESREA limit (˂100 mg/kg). Phosphate in soil can improve fertility of soil but when in excess, it

can affect plant growth. This is because high phosphate in soil affects its pH and nutrient availability

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Nitrates

The mean total Nitrogen (∑N) in the soil is 11.9±1.3mg/kg is higher than the control value of 7.0±0.1mg/kg. the

nitrate concentration is adequate for agricultural soil as it fell within the 10-50mg/kg. Nitrate is ideal in moderate

concentration but can be detrimental to plants in concentration.

Heavy Metal

The concentration of heavy metals in soil was compared with the NESREA standard limits. Iron at SPT, MPT

and EPT were 13.11±2.46, 36.03±0.42, 20.5±1.27mg/kg respectively with a mean of 23.2±0.76mg/kg and the

control value was 13.16±0.36mg/kg. Iron was below the regulatory limit of ≤100mg/kg. Iron deficiency can be

detrimental to plants at low concentration and it can be toxic to plants at high concentration. The availability of

iron also determines phosphorus and other nutrient availability.

The concentration of zinc metal in soil was compared with the NESREA standard limits. Zinc at SPT, MPT and

EPT were 4.47±0.19, 4.12±0.21, 3.65±0.21mg/kg respectively with a mean of 4.09±0.20mg/kg and the control

value was 1.02±0.01mg/kg. Zinc was below the regulatory limit of ≤100mg/kg. Zinc was within WHO/NESREA

limits and showed higher values compared to the control, indicating some level of impact. It is however observed

that the values for heavy metal concentration for effluent were far less than those of the soil. This may suggest

a possible accumulation of heavy metals in the soil as a result of continual discharge of production process

effluent on recipient land. This may however, not to be the only cause because other sources may be responsible

for the accumulation.

The concentration of lead metal in soil was compared with the NESREA standard limits. Lead at SPT, MPT and

EPT were 1.3±0.00, 1.63±0.18, 1.76±0.18mg/kg respectively with a mean of 1.56±0.0.50mg/kg and the control

value was 0.33±0.18mg/kg.

The mean cadmium level (0.14±0.03mg/kg) is well above the control (0.02±0.00 mg/kg) and exceedingly below

the WHO/NESREA limit (˂3mg/kg), suggesting limited heavy metal accumulation in the soil. The mean nickel

concentration (3.15±0.056 mg/kg) is significantly higher than the control (0.01± mg/kg), and still within the

WHO/NESREA limit (˂50 mg/kg). Lead, Copper, and Chromium levels were also at elevated compared to the

control, but remain within WHO/NESREA limits.

CONCLUSION

The study investigated the food industry effluent and compared the result with that obtained from the recipient

soil. The study revealed the presence of significant level of some contaminants in both the effluent and the

recipient soil. The effluent itself consistently shows high levels of oil & grease, turbidity, and acidity (low pH)

exceeding regulatory standards. The poorly treated effluent resulted to considerable pollution of the soil,

particularly with very high concentrations of oil & grease. While some other parameters in the soil remain within

standard limits, their elevated levels compared to the control indicate a clear impact from the industrial discharge.

This data strongly supports the need for effective wastewater treatment before discharge to mitigate

environmental degradation.

The results obtained from the study showed that the quality of effluent from the food industry was not

satisfactory. Oil and grease particularly had an extremely high value which points to prove that the food industry

did not treat their effluent before discharge. This fact can be confirmed by the values obtained for other

parameters such as the pH, BOD, COD and turbidity values. The turbidity values were all above acceptable

limits. COD values recorded several values above acceptable limits indicating the presence of chemically

oxidizable matter in the wastewater. A comparison of the wastewater with the control sample further confirmed

poor effluent quality as the control parameters fared better than the wastewater when both were compared with

the regulatory values.

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RECOMMENDATION

The disposal of quality effluent is very important if the recipient environment will be protected. It is therefore

advised that the concentration of base required for neutralization in the treatment process be determined by

carrying out a pilot study of the effluent to be treated. Also, an oil skimmer/ separator system such as described

by OSI (2019) should be put in place to take care of oil and grease contents of the discharged effluent. The

regulatory authority should generally ensure that industries embark on efficient treatment of their effluent and

also routine monitoring of the effluent before and after discharge. It was also noted that effluent was poorly

treated before discharged. Specialized waste management personnel should be involved to co-ordinate waste

management plan of the factory. The use of effluent from food industry as an alternative substrate source for bio

ethanaol production can be economically beneficial as it can reduce the need for treatment and discharge of the

effluent (Ratanapongleka et al, 2010).

The environmental challenges identified in the effluent analysis of the food industry in Port Harcourt, a three-

dimensional approach which should combine technological remediation, regulatory reform, and industry

accountability is recommended.

With the high concentrations of oil, grease, BOD, COD, and turbidity observed in the effluent samples,

appropriate remediation technologies should be adopted in the treatment of the effluent. Oil-Water Separators

systems should be installed. This is essential for removing fats, oils, and grease from wastewater. The coalescing

plate separators and dissolved air flotation units mostly used in food processing environments should be

installed. These are capable of reducing oil concentrations to less than 0.1 ppm and thus improve downstream

treatment efficiency. Early removal of oil in the treatment process improves water quality and reduces

maintenance needs in food processing plants (OSI, 2022).

Organic pollutants should be biologically treated from the food effluent using Bioreactors such as Membrane

Bioreactors. Sequencing Batch Reactors and aerobic reactors. These offer high-treatment efficiency. These

systems are ideal for the treatment of food industry effluents that has varying composition and they can be scaled

to meet different production volumes. Membrane Bioreactors are increasingly adopted in food factories due to

their ability to handle fluctuating wastewater composition and meet stringent discharge standards (Sperta

Systems, 2021). The system ensures high removal efficiency for BOD, COD, and nutrients and it is suitable for

water reuse applications.

Constructed Wetlands could be engineered from wetlands to provide a sustainable, low-maintenance solution

for nutrient and organic matter removal. The aerated subsurface flow wetlands are particularly effective in

reducing BOD and suspended solids while enhancing ecological aesthetics (Salah-Tazdaït & Tazdaït, 2023;

Odedra & Patel, 2022). Salah-Tazdaït & Tazdaït (2023) emphasized that aerated constructed wetlands can

significantly reduce organic pollutants in food industry wastewater, offering a sustainable alternative to

conventional treatment methods. These technologies should be adopted to meet specific effluent profile

treatment. This can then be integrated into an elaborate Environmental Management System (EMS) to ensure

consistent in performance and regulatory compliance.

The study showed that an effective compliance enforcement mechanism was lacking in Port Harcourt. There is

therefore the need to strengthen regulatory enforcement to improve compliance. Regulatory agencies such as

NESREA should be equipped with adequate resources for regular inspections and real-time monitoring. The

Penalties for non-compliance should be revised to serve as effective deterrents. Industries should be mandated

to publicly disclose effluent data to ensure transparency and community oversight. Also, it is necessary to reform

policies and introduce industry incentives to close existing policy gaps: Adoption of sustainable practices by

industries should attract incentives through tax breaks, green certifications, and public recognition for adopting

sustainable practices.

Effluent discharge standards should be updated to reflect current scientific benchmarks and should also include

emerging pollutants. A clear mechanism for accountability should be integrated into environmental policies to

define roles and responsibilities. Public enlightenment, engagement and education should be initiated to

encourage a culture of accountability and commitment to environmental matters. The Local communities should

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be empowered to participate in environmental monitoring and advocacy. This integrated approach would not

only address the technical deficiencies observed in the Port Harcourt case study but would also lay the

groundwork for scalable, sustainable solutions across Nigeria’s food processing sector.

The findings from the effluent analysis of the noodle pasta and vegetable oil production industry in Port Harcourt

reveal significant environmental degradation, characterized by elevated levels of oil, grease, Biological Oxygen

Demand (BOD), Chemical Oxygen Demand (COD), turbidity, and acidity. These indicators point to inadequate

wastewater treatment and poor adherence to environmental standards. However, the persistence of such pollution

is not merely a technical failure. It reflects deeper systemic challenges in enforcement, policy, and industry

accountability.

Enforcement Deficiencies

Environmental compliance enforcement is with a lack-lustre attitude despite the existence of regulatory agencies

such as NESREA. Regular inspections with real-time monitoring is absent making the industries to discharge

untreated effluents with minimal fear of sanctions. The absence of an oil-water separator in the studied facility,

which should be the primary pollution mitigation device suggests that regulatory monitoring is either ineffective

or absent. Finally, it is likely that due to the influence these industries have on the economy of the region, there

is limited transparency and political interference in the enforcement of compliance.

Policy and Regulatory Gaps

Environmental policies in Nigeria often lack effective mechanisms for accountability and integration because

outdated effluent standards fail to address emerging pollutants or reflect current ecological risks. The absence of

seasonal sampling in the study also underscores the need for more comprehensive regulatory frameworks that

mandate longitudinal data collection.

Implications for Policy and Practice

This study mirrors the challenges facing environmental monitoring and control in Nigeria’s industrial sectors.

These issues require a multi-dimensional approach such as updating regulatory standards, fostering community

engagement, strengthening institutional capacity, and incentivizing industry compliance. With these reforms, the

public health and ecological risks posed by untreated effluents will be effectively checked.

Finally, proper pollution management/ abatement practices should be implemented to ensure the preservation of

other uses of water. Thus, an in-house treatment of effluents from industries should be the paramount part of the

food production industry’s operations and the regulatory authority must take an uncompromising stand in

ensuring compliance. This is more so, if environmental sustainability is to be achieved.

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