1

AGRICULTURAL WASTEWATER FILTRATION AND RE-IRRIGATION SYSTEM: AN

INNOVATION TOWARDS THE RE-INTRODUCTION OF ROTATIONAL CROP FARMING

A Research Capstone Project

Presented to the Faculty Members of Senior High School

San Agustin National High School

San Agustin, Naujan, Oriental Mindoro

In Partial Fulfillment

Of the Requirements for the Subject

RESEARCH CAPSTONE

Science, Technology, Engineering and Mathematics

Presented by

Canarias, Mary Jhoy

Herilla, Cassandra

Larios, Djohn Jared

Mauro, Jerome
 1

Chapter I

INTRODUCTION

Nature and Importance of the Study

The Philippines, being an agricultural country, uses around

42.52% of its total land area for the sole purpose of growing

agricultural products for its people1. These numbers reflect how

important agriculture is in the overall economy of the

Philippines, as it is a form of livelihood common among the

majority of Filipino citizens.

The MIMAROPA region alone enlists around 542.2 thousand

hectares. The region's total agricultural land area comprised

19.7% of the region's total land area.

Total area harvested for all rice ecosystems during April to

June 2022 in the MIMAROPA Region reached 53,757 hectares. Among

provinces, Oriental Mindoro recorded the largest area harvested

at 27,142 hectares.

Among the provinces of the MIMAROPA Region, Oriental Mindoro

boasts a total agricultural area of 169,603.34 hectares

1
The World Bank. (2023) Agriculture. Retrieved on March 13, 2023, from:
https://bit.ly/42VDSut.
 2

(419,099.0 acres). Based on agricultural statistics, 85,244

hectares (210,640 acres) are devoted to palay production2.

Agriculture plays a significant role in the Philippine

economy. Involving about 40% of Filipino workers, it contributes

an average of 20% to the Gross Domestic Product. This output

comes mainly from agribusiness, which in turn accounts for about

70% of the total agricultural output.

Such numbers prove that agriculture plays a vital role in

running the country’s economic sector. More than half of the

Philippines’ 100 million people live in rural areas, and more

than a third of them are poor. Agriculture is the primary source

of income for poor rural people, and the only source for many of

the poorest households. Most of them depend on subsistence

farming and fishing for their livelihoods3. As such, of the total

population of the Philippines, around 22.86% work on the

agricultural sector of the economy.

Having a large population rely on crop cultivation and

agriculture as a source of income, the Philippines has endeavored

to strengthen its efficiency, which opened to a lot of

innovations that are beneficial to the country’s farmers.

2
Philippine Statistics Authority (2022). Agriculture. Retrieved on March 11,
2023, from: https://bit.ly/3MBIYqJ.
3
International Fund for Agriculture Development (2021). Agriculture.
Retrieved on March 11, 2023, from: https://bit.ly/3O5Ni2s.
 3

As crop growth entails to the majority of the country’s

agriculture sector, irrigation systems are employed for farmers

to utilize in making full use of their lands’ productivity. The

majority of all these farmers and agricultural landowners use

individual irrigation systems which draw water from the nearby

water bodies; in the locality’s case, from the nearby river and

the watersheds and underground springs.

However, due to the recent developments in the value of

various locally-grown crops as brought by changes in law

enforcement, the prices of these grown crops have become unstable

and are unsustainable in terms of its economic worth. In fact,

the inflation rate only worsened the current status of

agriculture in the country as field maintenance and product price

does not align with the people’s needs value-wise.

The problem arises when the resources and services used to

cultivate and manage these crops also cost considerable amounts

of money.

Considering these factors, cultivating only one type of crop

can be a huge burden financially due to the intensifying

instability of its values, especially rice. Hence, the

researchers believe that the re-introduction of rotational crop

farming can resolve the current economic issue by expanding the

 4

product options of farmers and increase the value of commonly

grown crops.

Through rotational crop farming, less fertilizer is

required, and less pollution is emitted in field maintenance.

Crop rotation is one of the most important practices within

sustainable agriculture. It involves planting different crops in

the same area at different times of the year or in different

years. This method reduces pesticide and herbicide use, which can

bio-accumulate in species, especially predatory birds.

Assessing this issue, with its significance in the

development of the current status of the agricultural sector of

the country, can open new pathways to introducing sustainable

systems of crop farming. Hence, the researchers’ goal in this

project was to innovate an irrigation system where rotational

crop farming is encouraged by utilizing and recycling runoff

water from prior use.

In tackling this study, an irrigation system was modeled,

along with modifications for built-in water runoff filters and

water storage that utilized sprinklers and tunnels for transport.

The filtered runoff was measured in terms of specific

parameters; namely, salinity, pH level, and quality or toxicity

through various methods and assays. The amount of water was be

 5

calculated and compared to standards depending on the crops’

needs.

The current problem and its nature led the researchers to

innovate and devise a system that can manage crop irrigation

runoff and filter it for reuse in the growth of other crops.

Objectives of the Study

Generally, this study aimed to innovate an irrigation system

that would filter the agricultural runoff from prior use of water

in fields and reuse for the growth of other crops.

Specifically, it aimed to:

1. measure the water salinity of the filtered wastewater runoff

and compare to the acceptable standards;

2. measure the pH level of the filtered wastewater runoff compare

to the acceptable standards; and

3. test the filtered water’s quality and toxicity through the

lettuce seed bioassay.

The results of this project were then used to rectify if the

system can open up the re-introduction of rotational crop

farming.
 6

Significance of the Study

This study would be beneficial for the following.

Environment. The innovation this study will bring can help

manage the use of water resources in crop cultivation by using

less water in fields. This can also help utilize wastewater as a

sustainable resource as it can be used to support the growth of

other crops instead of contaminating nearby soil.

Economy. This study can help the economy by introducing a

crop growth system that utilizes rotational cultivation of crops

to ensure sustainability of the resources used. This will also

open pathways to resolving current economic value issues

regarding certain crops.

Farmers. This study will help farmers by providing

alternative options crop options instead of cultivating only one

type. Through this, they can attain versatility in the products

they can offer and support environmentally friendly methods of

farming. This can also lessen their use of fertilizers and other

chemicals as the rotational crop farming sustains the soil’s

qualities.
 7

Future Researchers. The findings of this study can help fuel

other researchers to explore, improve, and expand this study to

serve a greater purpose in the community.

Scope and Limitations of the Study

This study aimed to innovate an irrigation system that would

filter the agricultural runoff from prior use of water in fields

and reuse for the growth of other crops.

The extent of this study was limited to the measurement of

the output water quality in terms of salinity, pH level, and

toxicity through various means and assays. The results were

compared to the standards provided by the International Rice

Research Institute and Department of Primary Industries.

This was conducted during the school year 2022-2023.

Definition of Terms

To prospect a clearer understanding of the study and its

concepts, the following terminologies were operationally and

conceptually defined.

Coconut Husk Fibers. Coconut fiber, obtained from unripe

coconut, is a natural fiber extracted from the husk of coconut.

The coconut is steeped in hot seawater, and subsequently, the

 8

fibers are removed from the shell by combing and crushing, the

same process as jute fiber4.

pH Level. The pH (pondus Hydrogenii) indicates a solution’s

acidity or alkalinity. The pH value generally varies between 0

and 14. pH value below 7.0 is considered acidic and pH value with

above 7.0 is considered basic; pH 7.0 is neutral. The pH of the

growing medium can be more acidic, basic or alkaline, or neutral;

so generally, plants thrive a water with a pH of about 5.5 to

7.55. In this study, the pH level of the filtered water was

measured.

Porous Concrete. Porous concrete is made by mixing large

aggregate material with mortar, creating lots of voids in the

cast concrete. Porous concrete is attractive because it traps

water and it can help route storm runoff and rain directly into

the soil, where it can nourish gardens and trickle down into the

water table6.

Rotational Crop Farming. In this study, rotational crop

farming refers to the simultaneous cultivation of a variety of

4
Yan, Y. (2016). Developments in Fibers for Technical Nonwovens. Woodhead
Publishing Series in Textiles. Retrieved on April 7, 2023, from:
https://rb.gy/67n2k
5
Department of Primary Industries (2013). Irrigation Water Quality. NSW
Government. Retrieved from: https://tinyurl.com/yj5zp34h
6
McMahon, M. (2023). What is Porous Concrete? About Mechanics. Retrieved on
April 8, 2023, from: https://rb.gy/gcdou
 9

crops in a certain area, utilizing a land area by growing crops

and switching each type across seasons.

Runoff. Runoff occurs when there is more water than land

can absorb. The excess liquid flows across the surface of the

land and into nearby creeks, streams, or ponds7. In this study,

the term runoff usually pertains to the runoff from agricultural

irrigation use.

Water Hyacinth Fibers. Water hyacinth fibers are the fibrous

materials obtained from the water hyacinth plant. This will be

used to create a water filter to be used in the water filtration

system. It is known for reducing the concentration of dyestuffs,

heavy metals and minimizing certain other physiochemical

parameters like TSS (total suspended solids), TDS (total

dissolved solids), COD (chemical oxygen demand) and BOD

(biological oxygen demand) in textile wastewater8.

Water Salinity. Salinity is the amount

of dissolved salts present in water. Salinity is typically

7
Rutledge, K., McDaniel, M., Teng, S., Hall, H., Ramroop, T., Sprout, E.,
Hunt, J., Bourdreau, D., Costa, H. (2022). Runoff. National Geographic.
Retrieved on April 7, 2023, from: https://rb.gy/2etvq
8
Priya Sanmuga, E., Selvan Senthamil, P. (2017). Water hyacinth (Eichhornia
crassipes) – An efficient and economic adsorbent for textile effluent
treatment – A Review. Arabian Journal of Chemistry Volume 10, Supplement 2.
Retrieved on April 9, 2023, from: https://rb.gy/ran7d
 10

measured with a salinometer, which calculates the amount or

weight of salt present in a specific volume of water9.

Water Toxicity. Water toxicity is the degree to which a

sample of water can damage an organism. Toxicity can refer to the

effect on a whole organism, such as an animal, bacterium, or

plant, as well as the effect on a substructure of the organism.

This is often caused by contamination of chemicals. In this

study, the toxicity was measured through the lettuce seed

bioassay10.

9
Ambulkar, A. (2019). Salinity. Britannica. Retrieved on April 9, 2023, from:
https://rb.gy/6yoga
10
Cornell University (2019). Toxicology: Why Use Lettuce Seeds as Bioassays?.
Environmental Inquiry. Retrieved from: https://bit.ly/42CltmS.
 11

Chapter II

REVIEW OF RELATED LITERATURE AND STUDIES

This section enlists the numerous literatures and researches

related to the concepts undermined in this study.

REVIEW OF RELATED LITERATURES

Agriculture in the Philippines

A vast majority of the Filipino populace relies on the

agricultural sectors as a form of livelihood. Around a quarter of

the entire Filipino citizens are currently employed within the

different sectors of agriculture. The Philippines, primarily

being an agricultural country and having a majority of its

citizens residing in rural areas, makes a hefty amount with the

products they provide through agricultural activities11.

11
Statista Research Department (2022). Share of Employed Persons in the
Philippines as of January 2022, by Sector. Retrieved on March 14, from:
https://bit.ly/42Cxfxl.
 12

Given the current status of the Philippine demographics, the

Gross Domestic Product (GDP) contribution of the agricultural

sector significantly increased in the past year. In summary, it

showed that the growth rate rocketed from 2.4% to 3.3% from July

to December 2022. It was also forecasted that the GDP growth

would continue its trend until 202512.

These values reflect how important agriculture is to the

livelihood of Filipinos. While these figures show significant

positive outputs, farmers are still boggled with challenges

facing the current economy.

Multiple challenges that face the Philippine Agriculture

were named. One such hurdle is the slow growth of the

agricultural sector in the Philippines, which had been attributed

to the rampant conversion of arable lands to residential

subdivisions, industrial parks, and resorts. Of the 30 million

hectares of land area, only one-third is used for agricultural

activities13.

On top of that, the country’s geographical location makes it

volatile to natural disasters such as flooding and drought,

further contributing to the decrease in production. Investments

in technology and innovation are necessary steps to diversify and

12
Trading Economics (2022). Agriculture. Retrieved from:
https://bit.ly/42MGnzk.
13
Statista Research and Development (2022). Agriculture in the Philippines -
Statistics & Facts. Retrieved from: https://bit.ly/430oD3D.
 13

transform the country’s agricultural output, along with increased

production support and improved policies that prioritize the

needs of farmers.

Aside from these challenges, other aspects that hinder the

growth of Philippine agriculture are the decline in arable land,

labor, capital, risks involved, and the current issues regarding

trade policies were also identified14.

The decline in land revolves around the repurposing of

arable land and using it either as residential areas or urbanized

due to the growing population. It was estimated that the

country’s arable land at 12.44 million hectares (ha). Since the

rural population has been growing, farm sizes have also been

declining, hence, there is no room for growth in this factor15.

The decline in labor and capital revolves around the

mechanization of farming systems. Through the use of agricultural

machines such as harvesters, the number of laborers in

agriculture continues to decline. In line with this, the

mechanization of agriculture in the Philippines led to farmers

investing in formal financing options to cope with capital

requirements.

14
Briones, R. (2021). Philippine Agriculture: Current State, Challenges, and
Ways Forward. ISSN 2508-0865. Retrieved from: https://bit.ly/3Bp4Krh.
15
Food and Agriculture Organization (2020). Land Use in Agriculture by
Numbers. Retrieved from: https://bit.ly/3BubCUd.
 14

Other such challenges are the risks associated with

agriculture. Such factors include the instability of market

prices, natural calamities, and the overall uncertainty of

product quality as it is being cultivated.

Field Maintenance and Irrigation

Field maintenance in agriculture accounts for a field’s

extent of productivity in terms of its crops’ growth. In

cultivating crops, the maintenance of its quality is imperative

to making full use of the land area.

Aside from soil quality, the quality of water that irrigates

agricultural fields should also be considered. 25 L of water (4

standard watering cans) is required for each square meter of crop

every week. This equates to 250,000 L per hectare or roughly

100,000 L per acre16.

These amounts of water should also fall between water

salinity level of around up to 1.9 dS/m without loss of yield and

pH level revolving around 6 pH17.

These requirements are generally met as the water drawn in

the irrigation systems used locally is from watersheds and

16
Westerveld, S. (2016). Small Plot Irrigation: Are You Applying Enough? On
Specialty Crops.Retrieved from: https://bit.ly/3LWUACM.
17
International Rice Research Institute (2021). Water-Wise Rice Production.
Retrieved from: https://bit.ly/3W68uHB.
 15

rivers. This ensures that the quality of water used is clean

state and is free of toxic materials.

There are currently three available types of irrigation

systems used in the agricultural lands of the Philippines –

namely, national, communal, and private/individual systems. As

the majority of local farmers use individual or communal

irrigation systems, costs on the use of said systems align with

costs of crude oil prices, which usually cannot be resolved

without capital investment18.

Having such costs in running irrigation for crops led the

researchers to innovate a system which can reuse agricultural

wastewater runoff and introduce rotational crop farming.

Agricultural Wastewater Runoff

The effects of agricultural wastewater runoff to the

environment varies, but clearly revolve around the eutrophication

and contamination of groundwater through the eroded chemicals

used agriculturally in crop cultivation.

Agricultural wastewater is primarily the excess water that

runs off the field at the low end of furrows, border strips,

18
National Irrigation System. Construction of Irrigation System. Management
Information Division-CORPLAN. Retrieved from: https://bit.ly/3IbMB3E.
 16

basins, and flooded areas during surface irrigation. This

wastewater is also referred to as irrigation tailwater19.

A main problem in the locality is that agricultural

wastewater is either sent directly to nearby water bodies without

treatment or just left on agricultural land to fester and

dissipate or seep deeper into the ground. This causes major

environmental impacts such as groundwater springs, watersheds,

water bodies, and the soil will be degraded easily through the

contamination of chemicals.

Rotational Crop Farming

Crop rotation was integral to farming before the widespread

adoption of chemically intensive practices. Growers used it to

prevent soil erosion, suppress weeds, and occasionally even

combat pests and diseases. While the crop rotation system is not

commonly practiced nowadays, its ecological and agronomic

benefits are indisputable20.

Crop rotation involves growing various plants in a set order

on the same land, contrasting with mono-cropping or random

succession. The number of plants might range from two or three in

19
California Agricultural Water Stewardship Initiative (2021). Wastewater
Management. Retrieved from: https://bit.ly/453SgTx.
20
EOS Data Analytics (2022). Sustainable Agriculture Practices & Their
Management. Retrieved from: https://bit.ly/3M8graN.
 17

simple rotations to twelve or more in complex ones. The average

crop rotation cycle takes up to eight years.

The greater soil fertility, fewer pests and crop diseases,

and higher yields can be achieved through the rotation of crops.

This method isn’t without its flaws, though, requiring a high

level of knowledge and additional attention to detail during the

various stages of implementation.

Crop rotation also improves water use efficiency by

increasing the amount of organic matter in the soil, which can

improve soil structure and water-holding capacity. Also, this

method helps preserve moisture in deep soil layers, which plants

can use during droughts. This way, farmers can reduce irrigation

water usage.

This, in line with the main goal of this study, which is to

reuse agricultural wastewater runoff to irrigate other crops,

served as the main basis of the introduction of rotational crop

farming in a local setting.

Water Recycling

Greywater use in agriculture, particularly in areas with

greater water shortages, can support water conservation efforts,

 18

the resilience of family farmed food systems, and food

security21.

Likewise, due to the potential financial and environmental

advantages, wastewater reuse in agriculture has been identified

as one of the most crucial management issues for the sustainable

use of the scarce fresh water supply, along with demand-oriented

water allocation and water desalination. Given that there are

more people on the planet and that there is a corresponding

increase in food consumption, as well as a steady increase in

population, and a corresponding decrease in water supply,

wastewater reuse initiatives must be started and supported on a

global scale22.

As it is possible to recycle water, different methods are

employed to recycle wastewater runoff. In this study, the

researchers innovated a system that utilized different materials

as filters to assess its water quality.

Water Filters

21
Silva, J., Borges, A., Fernandes, R., & Celeri, M. (2023). Greywater as a
Water Resource in Agriculture: The Acceptance and Perception from Brazilian
Agricultural Technicians. Science Direct-Agricultural Water Management Volume
280. Retrieved from: https://bit.ly/3o9BGAK.
22
Patel, S., & Pandya, S. (2022). Reuse of Reverse Osmosis Wastewater – A
Sustainable Solution for Agriculture. International Journal of Agricultural
Sciences. Volume 18 | OCAEBGD- 2022 | 57-61. Retrieved from:
https://bit.ly/3I75wN1.
 19

One of the water filters used is made from coconut coirs.

Coir fibers from coconut palm fruit hair are a by-product, if not

waste, of a sizable productive system that has significant added

value and can be used for a variety of purposes, particularly in

the food-related business. These fibers are thick, contain a lot

of lignin, and have microfibrillar angles that are close to 45°,

which supports their usage in geotextiles for soil amendment and

therefore in filters to purify both air and wastewater23 .

Another filter will be derived from water hyacinth fibers.

The uncontrollable growth of water hyacinth in water bodies has

led to reports that it is one of the most problematic plants in

the world. However, in its quest to absorb nutrients, it has made

it possible to use it in phytoremediation, along with a

combination of herbicidal control, integrated biological control,

and watershed management controlling nutrient supply to control

its growth24.

Also, by using this to treat wastewater in urban or

industrial regions, other beneficial byproducts can be created,

including ethanol, biogas, composting, animal and fish feed,

23
Cicconi, G., & Santulli, C. (2022). Use of Coir Fibers for Water and Air
Filter. Woodhead Publishing Series in Composites Science and Engineering. p.
345-359. Retrieved from: https://bit.ly/42EMvKg.
24
Rezania, S., Ponraj, M., Talaiekhozani, A., Mohamad, S., Din, N., Taib, S.,
Sabbagh, F., & Sairan, F. (2015). Perspectives of Phytoremediation Using
Water Hyacinth for Removal of Heavy Metals, Organic and Inorganic Pollutants
in Wastewater. Journal of Environmental Management. Volume 163, 1 November
2015, Pages 125-133. Retrieved from: https://bit.ly/42EMLZK.
 20

power plant energy (briquettes), and fiber board manufacturing.

The use of invasive plants in pollution abatement

phytotechnologies can undoubtedly help for their sustainable

management in treating wastewater, focusing on the future

features of phytoremediation.

Lastly, although unorthodox and inorganic, porous concrete

will be used as a filter for water. An innovative approach for

minimizing the amount of runoff from paved areas is the use of

porous concrete25.

Porous concrete has been utilized in riverbank-protecting

constructions in Japan as a novel sort of ecological material.

Some unique ecologically beneficial capabilities of porous

concrete, which has an internal honeycomb void structure that is

interconnected, include sound absorption, water permeability,

planting grass, and water quality purification26.

Parameters to be Measured

This study measured the factors of water quality which

affect the growth of standard crops – mainly water salinity, pH

level, and its toxicity.

25
Lange, A. (2015). Synthesis of Porous Carbon Monoliths by Using Porous
Concrete as Template. Part II: Investigations of Mechanical Properties. Wiley
Online Library. Retrieved from: https://bit.ly/3nZCTdV.
26
Zhang, R., Kanemaru, K., & Nakazawa T. (2015). Purification of River Water
Quality Using Precast Porous Concrete Products. Journal of Advanced Concrete
Technology. Retrieved from: https://bit.ly/4537pEi.
 21

Water salinity is the most important abiotic stress that

inhibits growth and productivity of crops, and it is one of the

world’s oldest and most widely distributed environmental

challenges. Additionally, salinity's impact on photosynthetic

rate is influenced by both plant species and salt content. There

is evidence that salinity may increase photosynthesis at low salt

concentrations. On past researches, it was noted that while

stomatal conductance remained unchanged at low salinity and

dropped at high salinity, photosynthetic rate increased at low

salinity and decreased at high salinity27.

Similarly, the use of saline irrigation water for

agricultural cultivation has a detrimental effect on the

interactions between the soil, water, and plants. Impact varies

depending on the salinity of the water; high salinity reactions

have a strong impact, whereas low salinity responses have a

minimal impact. Lower crop growth rates and significant yield

losses are caused by the effects of water salinity on the

connections between soil, water, and plants, which also leads to

lower-quality plant products28.

27
Safdar, H. (2019). A Review: Salinity on Plant Growth. Institute of Soil and
Environmental Sciences, University of Agriculture, Faisalabad, Pakistan.
Nature and Science 2019;17(1). Retrieved from: https://bit.ly/3MpCYB0
28
Pascale, S., Orsini, F., & Pardossi, A. (2013). Irrigation Water Quality
for Greenhouse Horticulture. Department of Agricultural Engineering and
Agronomy, University of Naples Federico II, Italy. Retrieved from:
https://bit.ly/3pIh6Io.
 22

The pH (pondus Hydrogenii), on the other hand, indicates a

solution’s acidity or alkalinity. The pH value generally varies

between 0 and 14. pH value below 7.0 is considered acidic and pH

value with above 7.0 is considered basic; pH 7.0 is neutral. The

pH of the growing medium can be more acidic, basic or alkaline,

or neutral; so generally, plants thrive a water with a pH of

about 5.5 to 6.529.

Lastly, water toxicity is the evaluation of the toxicity of

wastewater, polluted sediments, and water streams is a crucial

component in monitoring environmental pollution. Rapid,

sensitive, and cost-effective evaluation of biological effects

can provide precise data for ecotoxicity assessment. In the

recent times, many biological tests based on higher and lower

creatures, including fish, invertebrates, plants, algal cells,

and microbial bioassays, have been employed to determine the

toxicity of substances30.

In this study, the water toxicity and quality will be

measured through the Lettuce seed bioassay. The said bioassay

29
Department of Primary Industries (2013). Irrigation Water Quality. NSW
Government. Retrieved from: https://tinyurl.com/yj5zp34h.
30
Hassan, S., Ginkel, S., Hussein, M., Abskharon, R., & Oh, S. (2016).
Toxicity Assessment Using Different Bioassays and Microbial Biosensors.
Environment International. Volumes 92–93, July–August 2016, Pages 106-118.
Retrieved from: https://bit.ly/3W0JrWt.
 23

involves the determination of a sample’s toxic material content

and its effect to the germination of lettuce seeds31.

RELATED STUDIES

This project hinges on the studies that follow as bases for

the conduct of this study.

32
The main basis of this study is G. Kratcha’s (2022) study

which aimed to determine ways to stop drainage water from eroding

nutrients and chemically treated soil into waterways, thereby

preventing eutrophication.

In their study, various strong base anion exchange resins

and crop residue-based filters were used. Through the simulation

of drainage tilling on tile platforms, they measured the pH

level, Salinity, and Nitrate and Phosphate content of the

filtered runoff. After said tests, they also conducted the

lettuce seed bioassay test to determine its toxicity.

Through their extensive procedures, the results showed that

strong base anion exchange resins were the best medium to use in

filtering the water runoff. Among the organic mediums they

31
Cornell University (2019). Toxicology: Why Use Lettuce Seeds as Bioassays?.
Environmental Inquiry. Retrieved from: https://bit.ly/42CltmS.
32
Kratcha, G. (2022). An Innovative Approach to Manage the Environmental
Impact of Agricultural Drainage Water. Hankinson Public School. Retrieved
from: https://bit.ly/42SzzAc.
 24

tested, coconut husk filters proved to be the best material to

use.

They concluded that the use of strong anion base exchange

resins and coconut husk filters could prevent eutrophication of

water and recovery of nutrients and contaminants in water. The

only variance in both materials’ performance hinged upon the

coconut husk filters’ longevity, which break down and release

nutrients into the water over time.

This study served as the basis for choosing the methods to

test in this study. The parameters measured, namely salinity, pH

level, and toxicity, were adapted from this study to prove its

capabilities on a local setting.

33
Another study used as foundation in this study was J.

Kerr, J. DePinto, D. McGrath, S. Sowa, and S. Swinton’s (2016)

study which revolved around proposing ways to manage the impacts

of agricultural irrigation and farming to the quality of the

water surrounding the Great Lakes Basin.

They emphasized in their paper that the “wastewaters should

and can be reused through conventional methods”. They proposed

creating water treatment plants near the water bodies and

33
Kerr, J., DePinto, J., McGrath, D., Sowa, S., & Swinton, S. (2016).
Sustainable Management of Great Lakes Watersheds Dominated by Agricultural
Land Use. Journal of Great Lakes Research. Volume 42, Issue 6, December 2016,
Pages 1252-1259. Retrieved from: https://bit.ly/3OabMYc/
 25

integral parts of the Great Lakes watershed areas to avoid

contamination and eutrophication.

Their efforts provided the researchers an idea to use a more

sustainable and plausible measure, primarily through rotational

crop farming, to compensate for the insufficiency of the

locality’s funds to support treatment plants.

34
In line with this, K. Shah, B. Modi, H. Pandey, A. Subedi,

G. Aryal, M. Pandey, and J. Shrestha concluded in their study

that diversified crop farming through rotational cultivation can

open long-term profitability and provide farmers flexibility on

the products they can provide.

Aside from this, the method can also ensure field fertility

and minimize environmental impacts of chemical use in fields as

the different crops help keep the soil refreshed.

SYNTHESIS

The presented literature and studies in this section

provided the founding bases for determining the core objective of

this study – to innovate an irrigation system that filter the

agricultural runoff from prior use of water in fields and reuse

for the growth of other crops.

34
Shah, K., Modi, B., Pandey, H., Subedi, B., Aryal, G., Pandey, M., &
Shrestha, J. (2021). Diversified Crop Rotation: An Approach for Sustainable
Agriculture Production. Volume 2021 | Article ID 8924087. Retrieved from:
https://bit.ly/3BrZrXZ.
 26

The main concept of this project was based upon G. Kratcha’s

study which aimed to determine ways to stop drainage water from

eroding nutrients and chemically treated soil into waterways,

thereby preventing eutrophication. The methodologies and

parameters tested in this study were also modeled after Kratcha’s

study, which generally measured the quality of filtered

wastewater.

The filters chosen for this study hinged upon the studies of

multiple researchers. The water hyacinth filter was chosen as it

showed feasibility of promising water filter capabilities as

suggested by I. N. Nwachukwu (2019). The coconut coir filter was

chosen based on the study of N. R. Wijesekara (2019). Lastly, the

porous concrete filter was chosen based on the study of S. V.

Hatzikiriakos (2015).

Through the findings of the aforementioned studies, the

researchers were able to grasp the concept which surrounds the

project at hand. Using the adapted methodologies and literatures

which serve as bases, the results of this study were rectified as

to whether the output system had the capability to assist the

agricultural sector.
 27

Chapter III

METHODOLOGY

Materials and Equipment

This study utilized a model system which requires a pump,

storage/reservoir, and water filters. The water filters used are

drawn from coconut husk fibers, water hyacinth fibers (water

lily), and porous concrete.

Model Diagram

This study utilized the following model design.

Water
Storage
 28

Irrigated Field 1 Irrigated Field 2

(Rice Crops) (Other Crops)

Water
Filters

Figure 1. Proposed Agricultural Wastewater Filtration and Re-

Irrigation Model Diagram

The model roughly shows how this system worked. The model

encouraged the use of rotational crop farming through division of

an agricultural area into sectors where different crops can be

grown.

However, for the sake of convenience an experimental model

was designed and used for the purpose of testing the parameters

in this study. The experimental model is described as follows.

Water
Storage
 29

Water Pump

Filter A
Field

Filter B Filter C

Figure 2. Agricultural Wastewater Filtration and Re-Irrigation

Experimental Set-up Model Diagram

General Procedure

First, the field was irrigated with clean water. As the

field is designated for rice crops, the soil was treated with

fertilizers and other chemicals to ensure development of the

crops. This ensured that the water runoff used in irrigating the

field would be contaminated with chemicals.

In order to fully utilize the water runoff, the water was

filtered using different materials. In this study, the chosen

materials were coconut coir fibers, live water hyacinth, and

porous concrete filters as these materials exhibit

characteristics suitable to filtering wastewater.

These filters were then attached to the sides of the field

where the runoff will be accumulated and filtered.

 30

Figure 3. Agricultural Wastewater Filtration and Re-Irrigation

Experimental Set-up

Quantification Methods

As per the general process of water filtration and

irrigation discussed prior to this section, certain parameters

were measured in order to acquire the needed results for this

study.

Some of these parameters were water salinity and water

toxicity. These parameters were associated with factors

concerning water that affect the growth of crops. In this study,

these parameters were measured to ensure that the quality of

water was suitable to the growth of crops. Other factors such as

water toxicity level and the amount of filtered water were also

measured.

The methodologies to the measurement of said parameters were

discussed as follows.
 31

Measuring the Water Salinity

The water salinity was measured using a digital tester in a

sample of collected filtered runoff. This was conducted for 5

trials and averaged. The results were then compared to the

standards issued by the International Rice Research Institute

(IRRI) for the growth of rice crops which need a water salinity

of less than 1.9 dS/m.

Measuring the pH Level

The water pH level will be measured by using a digital

tester in a sample of collected filtered runoff. This will be

conducted for 10 trials and will be averaged. The results will

then be compared to the standards issued by the International

Rice Research Institute (IRRI) for the growth of rice crops which

need a pH level of 6 pH or 15-30 μM.

Testing Water Quality and Toxicity

Another parameter measured was the water quality and

toxicity. This measure was quite complicated to quantify, but

through the use of various assays, the measurement of the

sample’s toxicity was possible.

The water toxicity was measured using the Lettuce Seed

Bioassay, where a lettuce seed was exposed to the water sample

 32

for a certain amount of time. In this assay, lettuce seeds were

doused in bleach for 15-20 minutes to eliminate impurities that

may affect the germination of the seed. The seeds were then

placed in a plate lined with tissue paper and watered with the

corresponding water samples and were left to grow for 2 days. The

seed’s germination and growth after the time period determined

the water toxicity of the sample runoff water.

The listed methodologies were employed in order to test the

capabilities and potential of the agricultural wastewater runoff

filtration and irrigation system.

Chapter IV

RESULTS AND DISCUSSION

The subsequent information delineates the findings of the

investigation conducted by the researchers, wherein they examined

the salinity, pH level, toxicity, and quality of the filtered

runoff. The ensuing findings are as follows:

1. Salinity Measurement of the Filtered Wastewater Runoff

Table 1 displays the findings obtained from measuring the

salinity of the water derived from the runoff, which was filtered
 33

through coconut husk. The average measurement of water salinity

recorded in this study is 0.651 dS/m.

As per the guidelines set forth by the International Rice

Research Institute (IRRI), a water salinity measurement of less

than 1.9 dS/m is considered acceptable for supporting crop

growth.

Therefore, the concentration of dissolved salts observed in

the filtered runoff, which amounts to 0.651 dS/m, falls below

this threshold. Consequently, it adheres to the standards

established by the IRRI, indicating that the filtered runoff can

be reused for the cultivation of plants.

Table 1. Water Salinity Test Results of the Filtered Wastewater

Runoff Using Coconut Husk Fiber Filter

SAMPLES WATER SALINITY

1 0.676 dS/m
2 0.655 dS/m
3 0.634 dS/m
4 0.636 dS/m
5 0.667 dS/m
AVERAGE 0.653 dS/m
 34

Figure 4: Water Salinity Test Results of Filtered Water Samples

Using Coconut Husk Fibers
Table 2 presents the findings acquired through the

measurement of water salinity in the runoff, which underwent

filtration using water hyacinth fibers.

The study records an average water salinity measurement of

0.653 dS/m. It is worth noting that this result complies with the

prescribed benchmarks set by the International Rice Research

Institute (IRRI), as it remains below the threshold of 1.9 dS/m.

This implies that the water hyacinth filter exhibited superior

efficiency compared to the other filters, as it successfully

reduced the salinity of the runoff to the greatest extent.

Consequently, this discovery suggests that the filtered runoff,

treated by the water hyacinth, is suitable for reuse in

agricultural practices such as crop cultivation.

Table 2. Water Salinity Test Results of the Filtered Wastewater

Runoff Using Water Hyacinth Fiber Filter

SAMPLES WATER SALINITY

1 0.645 dS/m
2 0.648 dS/m
3 0.643 dS/m
4 0.616 dS/m
 35

5 0.626 dS/m
AVERAGE 0.636 dS/m

Figure 5: Water Salinity Test Results of Filtered Water Samples

Using Water Hyacinth
The tabulated data furnished herein presents the outcomes

obtained from the assessment of water salinity within the runoff,

subsequent to its filtration by means of pervious concrete.

According to the information disclosed in the table, the

study reveals an average measurement of water salinity at 0.658

dS/m. It is crucial to emphasize that this recorded value aligns

with the established benchmarks stipulated by the International

Rice Research Institute (IRRI), as it remains notably below the

specified threshold of 1.9 dS/m.

Accordingly, this significant discovery signifies that the

runoff water, subsequent to undergoing filtration through porous

concrete, attains a state of suitability for subsequent

employment in agricultural practices, including the cultivation

of other crops.

Table 3. Water Salinity Test Results of the Filtered Wastewater

 36

Runoff Using Pervious Concrete Filter

SAMPLES WATER SALINITY

1 0.658 dS/m
2 0.674 dS/m
3 0.641 dS/m
4 0.648 dS/m
5 0.668 dS/m
AVERAGE 0.658 dS/m

Figure 6: Water Salinity Test Results of Filtered Water Samples

Using Water Hyacinth

2. pH Level Measurement of the Filtered Wastewater Runoff

Table 4 shows the recorded pH level measurements for

individual samples of filtered water runoff, which underwent

filtration using coconut husk.

Every individual sample exhibits an elevated pH level, and

this is further evidenced by the calculated average pH value of

7.92. As outlined by the Department of Primary Industries (2013),

optimal conditions for plant growth typically necessitate a pH

range between 5.5 and 7.5 in the water. The average pH level
 37

obtained from the tests conducted falls outside this optimal

range, albeit in close proximity. This alkaline nature of the

water may potentially hinder plant growth.

Table 4. pH Level Test Results of the Filtered Wastewater Runoff

Using Coconut Husk Fiber Filter

SAMPLES pH LEVEL
1 7.96
2 7.92
3 7.96
4 8.08
5 7.70
AVERAGE 7.92

Figure 7: pH Level Test Results of Filtered Water Samples Using

Coconut Husk Fibers
Table 5 presents the recorded pH level measurements for

individual samples of filtered water runoff, which underwent

filtration using water hyacinth.

It can be inferred from the table below that the average pH

level of the filtered wastewater runoff through water hyacinth is

9.09. This also fails to adhere to the standards for the pH level

for plant growth which is the 5.5 to 7.5 range. Unfortunately,

 38

based on the recorded average pH level observed in the samples

treated with water hyacinth filtration, it appears that the water

might be excessively alkaline and inadequately filtered to

facilitate the growth of alternative crops.

Table 5. pH Level Test Results of the Filtered Wastewater Runoff

Using Water Hyacinth FIber Filter

SAMPLES pH LEVEL
1 8.64
2 8.46
3 8.87
4 9.08
5 9.09
AVERAGE 8.82

Figure 8: pH Level Test Results of Filtered Water Samples Using

Pervious COncrete
Table 5 illustrates the pH level measurements obtained from

distinct samples of filtered water runoff, which underwent

pervious concrete filtration.

 39

The data presented in the table reveals that the average pH

level of the filtered wastewater runoff, utilizing pervious

concrete as a filtration medium, is recorded as 8.01. Notably,

this average pH level deviates from the established standards for

optimal plant growth, which typically fall within the pH range of

5.5 to 7.5.

Regrettably, based on the average pH level recorded in the

samples treated with pervious concrete filtration, it suggests

that the water may possess excessive alkalinity and inadequate

filtration efficiency, thereby posing limitations on its

suitability for cultivating alternative crops.

Table 6. pH Level Test Results of the Filtered Wastewater Runoff

Using Pervious Concrete Filter

SAMPLES pH LEVEL
1 7.92
2 8.10
3 7.90
4 8.12
5 7.99
AVERAGE 8.01
 40

Figure 9: pH Level Test Results of Filtered Water Samples Using

Pervious COncrete
3. Water Toxicity Test Results through Lettuce Seed Bioassay

Table 7 presents the results of the water toxicity test of

the water samples collected using coconut husk fiber through the

lettuce seed bioassay.

It was observed that all the seeds exposed in all five

samples of filtered water using the coconut husk fiber failed to

germinate within 48 hours at normal conditions.

Based on the previous observations involving the water

samples’ pH and salinity levels, it was revealed that the high

alkalinity of the water affected the germination of the seeds.

After careful observation and further research, it can be

concluded that the high pH levels of the water samples inhibited

the germination of the seeds, which may have caused nutrient

deficiency and damage to the development of the root’s cell

membranes.
 41

Table 7. Water Toxicity Test Results of the Filtered Wastewater

Runoff Using Coconut Husk Fiber Filter through Lettuce
Seed Bioassay

SAMPLES SEED GERMINATION

1 Failed to Germinate
2 Failed to Germinate
3 Failed to Germinate
4 Failed to Germinate
5 Failed to Germinate

The results of the water toxicity test conducted on the

water samples collected using water hyacinth and assessed through

the lettuce seed bioassay are presented in Table 7.

The findings revealed that none of the seeds exposed to any

of the five filtered water samples using water hyacinth were able

to germinate within 48 hours under normal conditions.

In all samples, regardless of the filtration method used

(coconut husk fibers, water hyacinth fibers, or pervious

concrete), none of the seeds showed signs of germination within a

48-hour period under normal conditions. Further examination and

research indicated that the high pH levels in the water samples

hindered seed germination by potentially causing nutrient

deficiency and damaging the development of the root's cell

membranes.
 42

Table 8. Water Toxicity Test Results of the Filtered Wastewater

Runoff Using Water Hyacinth Fiber Filter through
Lettuce Seed Bioassay

SAMPLES SEED GERMINATION

1 Failed to Germinate
2 Failed to Germinate
3 Failed to Germinate
4 Failed to Germinate
5 Failed to Germinate

Table 8 displays the outcomes of the water toxicity test

conducted on the water samples collected using pervious concrete

and evaluated through the lettuce seed bioassay.

The results indicated that none of the seeds exposed to any

of the five filtered water samples utilizing water hyacinth were

capable of germinating within 48 hours under normal

circumstances.

Upon careful examination of the previous observations

pertaining to the pH and salinity levels of the water samples, it

became apparent that the heightened alkalinity of the water had

an adverse effect on seed germination. Further investigation and

analysis revealed that the elevated pH levels in the water

samples hindered seed germination by potentially inducing

nutrient deficiencies and impairing the development of the root's

cell membranes.
 43

Table 9. Water Toxicity Test Results of the Filtered Wastewater

Runoff Using Pervious Concrete Filter through Lettuce
Seed Bioassay

SAMPLES SEED GERMINATION

1 Failed to Germinate
2 Failed to Germinate
3 Failed to Germinate
4 Failed to Germinate
5 Failed to Germinate
 44

Chapter V
SUMMARY OF FINDINGS, CONCLUSION, AND RECOMMENDATIONS

This chapter presents a thorough summary of the research's

findings, conclusions, and recommendations. It encapsulates the

significant insights and implications derived from the data

analysis.

SUMMARY OF FINDINGS

1. Measurement of Water Salinity of the Filtered Wastewater

Runoff and Comparison to IRRI Standards

The salinity levels of the filtered runoff were evaluated in

three distinct treatments: wastewater runoff filtered through

coconut husk fiber, wastewater runoff filtered through water

hyacinth, and wastewater runoff filtered through pervious

concrete. Each treatment comprised five individual samples and

averaged.

In the first treatment, it was determined that the average

concentration of dissolved salts in the filtered wastewater

runoff was 0.651 dS/m. For the wastewater runoff filtered by

 45

water hyacinth, the average water salinity of the five samples

was 0.636 dS/m, which was the lowest among the other treatments.

Lastly, for the wastewater runoff filtered by pervious concrete,

the average water salinity was 0.658 dS/m.

All of the average salinity levels of the filtered

wastewater runoff in each treatment met the standards established

by the International Rice Research Institute (IRRI) since they

were all below 1.9 dS/m.

2. Measurement of pH Level of the Filtered Wastewater Runoff and

Comparison to Acceptable Standards

The pH levels of the filtered runoff were assessed in three

distinct treatments: coconut husk fiber filtration, water

hyacinth filtration, and pervious concrete filtration of

wastewater runoff. Each treatment consisted of five individual

samples, and their average pH levels were determined.

The average pH level of the wastewater filtered through

coconut husk fiber was found to be 7.92, which was the closest to

the recommended pH range for optimal plant growth (5.5-7.5)

 46

according to the Department of Primary Industries (2013).

Conversely, the wastewater runoff filtered through water hyacinth

exhibited an average pH level of 8.97. Lastly, the wastewater

runoff filtered through pervious concrete had an average pH level

of 8.01.

It is noteworthy that all average pH levels observed in each

treatment failed to meet the standards outlined by the Department

of Primary Industries, and they were excessively alkaline to

support the growth of another batch of plants.

3. Water Toxicity Test Results through Lettuce Seed Bioassay

The study evaluated the water toxicity of filtered runoff

using three treatments: coconut husk fiber filtration, water

hyacinth fiber filtration, and pervious concrete filtration of

wastewater runoff. Each treatment consisted of five individual

samples, and the germination of lettuce seeds was monitored.

In all samples, regardless of the filtration method used

(coconut husk fibers, water hyacinth, or pervious concrete), none

of the seeds showed signs of germination within a 48-hour period

under normal conditions.

 47

Subsequent examination unveiled that elevated pH levels in

the water samples impeded seed germination, possibly resulting in

nutrient inadequacy and harm to the cell membranes of growing

roots.

CONCLUSIONS

Based on the findings of the study, the following

conclusions were drawn:

1. Coconut husk fiber, water hyacinth, and pervious concrete

exhibit potential as viable filtration options to reduce

salinity in wastewater runoff and adhere to the salinity

standards set by the IRRI.

2. Although coconut husk fiber filtration demonstrated

potential in approaching pH levels within the recommended

range, none of the three filtration treatments met the pH

standards set by the Department of Primary Industries for

supporting optimal plant growth. Consequently, the

suitability of these filtration methods, including coconut

husk fiber filtration, for rotational crop farming may be

questionable.

3. The observed inhibition of seed germination could be

attributed to potential nutrient deficiency and damage to

 48

the development of root cell membranes caused by the

elevated pH levels of the filtered wastewater runoff.

RECOMMENDATIONS

Given the conclusions and results obtained, the subsequent

suggestions were proffered:

1. Utilizing water hyacinth fibers as a filtration medium

for wastewater runoff can effectively reduce salinity levels

and meet the standards set by the International Rice

Research Institute (IRRI), making it a favorable option for

water treatment in agricultural practices, including

rotational crop farming.

2. It is advised to consider modifying the filters,

particularly the coconut husk filter, or to investigate

alternative filtration methods or treatments capable of

effectively reducing the alkalinity of wastewater runoff to

facilitate plant growth.

3. Address the high pH levels in the filtered runoff

samples from the different filtration treatments (coconut

husk fiber, water hyacinth fiber, and pervious concrete).

This can be achieved through appropriate adjustments or

treatments to reduce pH levels, allowing for improved seed

 49

germination by preventing nutrient deficiency and protecting

the development of root cell membranes.

4.For future researchers, it is important to note that while

the proposed system is operational, it may not be the most

optimal design for practical and real-life implementation.

Therefore, it is recommended that a more adaptable and

versatile model be developed to cater to the diverse

applications of this study in the future.

 50

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