Closed-Loop Water Remediation and Biomass System

Environmental Brief: Technical Design Considerations for [Ayni Bahay] Water Services Cooperative: Closed-Loop Water Remediation and Biomass System

Overview

This document outlines the technical framework and design for a water remediation system using phytoremediation principles with native reed species, wild rice cultivation, and water hyacinth biomass in a closed-loop cycle. The system will be designed to provide a sustainable source of clean water for 400 citizens in the Ayni Bahay Water Services Cooperative, located in the Philippines. The system incorporates water storage, rainwater harvesting, greywater recycling, and biomass management to produce biochar, compost, and terra preta for soil regeneration.

1. Core System Objectives

Clean Water Production: Supply sufficient potable water for washing, cleaning, cooking, showering, and laundry for 400 cooperative members.
Phytoremediation: Use of native Philippine plants (especially reed species) and water hyacinths for natural greywater filtration.
Biomass Management: Use the excess biomass from water hyacinth for composting, worm castings, and biochar production.
Sustainability: Create a circular system where water is continuously purified, and biomass production feeds soil improvement for gardens and agriculture.
Ecological Integrity: Promote the use of environmentally friendly soaps to protect the integrity of the filtration system.

2. System Components

2.1. Rainwater Harvesting and Storage

Input: Rainwater is collected from roofs and surfaces, stored in ponds or cisterns, and pumped into the filtration system.
Holding Ponds: Initial holding ponds collect the rainwater, and some water will be stored to balance dry seasons.
Capacity Calculation: Based on rainfall patterns in the Philippines, storage will need to handle variability, especially during the dry season.

2.2. Phytoremediation Ponds

Multiple Ponds: Water passes through a series of interconnected ponds where plants, gravel, sand, and biochar provide filtration.
Native Reed Species (Typha): Selected for their ability to remove nutrients, heavy metals, and toxins.
Wild Rice (Zizania latifolia): Grown in specific areas for food production, with dual benefits of phytoremediation and food supply.
Water Hyacinth (Eichhornia crassipes): Grown for its massive biomass production and filtration capabilities.

Water Hyacinth (Photo Credit Canva Pro / Getty)

Physical Filtration: Initial filtration using gravel, sand, and charcoal to remove sediment and particles.
Chemical Filtration: Activated biochar will absorb chemicals, while plants will uptake nutrients and toxins.

2.3. Circulation and Aeration

Gravity-Driven Flow: Water flows between ponds using natural slopes or small pumps, reducing the need for high-energy circulation.
Aeration: Introduce cascades or waterfalls between ponds to oxygenate water and encourage microbial activity.

2.4. Biomass Production and Management

Water Hyacinth Biomass:
- Harvested regularly for composting, worm castings, and biochar production.
- Biomass used for creating terra preta (a type of fertile soil) through biochar enrichment.
Biochar Production:
- Hyacinth and other organic matter are pyrolyzed at low oxygen levels to produce biochar.
- Biochar is added to soil, improving water retention, nutrient availability, and carbon sequestration.
Composting and Worm Castings:
- Excess biomass and plant material are composted to produce organic fertilizers.
- Worm castings help create nutrient-rich compost, which can be added to gardens and agricultural beds.

2.5. Water Recycling

Greywater Treatment: Greywater from washing and cleaning is returned to the system for filtration and phytoremediation.
Ecological Soaps: Participants must use biodegradable, eco-friendly soaps to prevent contamination with harmful chemicals.

3. Water Needs and Pond Sizing Calculations (for 400 persons)

3.1. Water Demand for 400 People

Daily Water Usage Per Person:
- Average water consumption for cleaning, washing, and cooking: 100 liters/person/day.
- Total water requirement: 100 liters/day x 400 people = 40,000 liters/day (40 cubic meters/day).

3.2. Pond Sizing

Rainwater Storage:
Given a mean annual rainfall in the Philippines (approximately 2,000–4,000 mm/year), we calculate the storage needed for dry seasons.
Assume a minimum storage capacity for 60 dry days: 40,000 liters/day x 30 days = 2,400,000 liters (2400 cubic meters).
Ponds for rainwater storage need to hold at least 2,400 m³ (ideally more for safety margins).
At 100 cm depth, this implies an area requirement of no less than 2400 square meters for the water. With paths, and space for a few trees .. a good target for 100 persons, is 4000 square meters of space for the water storage and remediation ponds system.

3.3. Filtration Pond Area

Phytoremediation Pond Size:
Based on studies of similar systems, phytoremediation typically requires 1-2 square meters of pond area per person.
For 400 people: 2 m²/person x 400 people = 800 m² of total phytoremediation area.
The filtration process requires multiple ponds in series, meaning this 800 m² would be distributed over perhaps 10 or 12 ponds for effective filtration.

3.4. Total System Area

Storage and Filtration: In addition to the filtration ponds (800 m²), we need space for the storage ponds, which could be 2400 m² for water storage (assuming an average depth of 1 meter for rainwater holding ponds).
Total Required Area: Approximately 4000 m² for water storage, filtration, and biomass growth. This does not include surrounding paths and infrastructure but covers the core pond system.

4. Circular Biomass and Biochar Production Cycle

4.1. Biomass Harvesting

Water Hyacinth: This fast-growing plant can produce up to 70-100 tons of biomass per hectare per year in tropical climates.
Harvested biomass is dried and processed for compost and biochar production.

4.2. Biochar Production

Pyrolysis Process: Excess hyacinth and plant material are placed in a low-oxygen pyrolysis kiln to create biochar. Biochar is then used to improve soil quality and act as a long-term carbon sink.
Application: Biochar is combined with compost or added directly to agricultural beds to create terra preta, boosting crop productivity, improving soil structure, and aiding water retention.
Other clean biomass which is found onsite or brought onsite can also be introduced into the biomass production system. leading to extensive terra preta production. This bio-char can be used for the remediation ponds, and may even be shared with community cooperative participants.

4.3. Composting and Soil Regeneration

Composting: Biomass from hyacinths, reeds, and food waste is composted to produce nutrient-rich organic matter.
Worm Castings: Worms are introduced to compost piles to produce highly fertile worm castings, which can be mixed into garden soil. This is a sub-operation which would benefit the overall system – another layer of symbiosis for the community – collaboration with the worms!

4.4. Soil Enhancement via Terra Preta

Terra Preta: This soil-enriching method combines biochar, compost, and natural soil, increasing the fertility of garden beds, improving microbial activity, and ensuring sustainable agricultural production.

5. Ecological Soap and System Health

5.1. Greywater Input

All participants must use biodegradable, ecological soaps and detergents to ensure that the greywater entering the system does not contain harmful chemicals or microplastics.

5.2. Phytoremediation Impact

With eco-friendly soap use, the plants and filtration media can effectively remove nutrients and toxins from greywater, ensuring the system maintains its effectiveness in treating wastewater.

6. Integrating Water Chestnuts into the Phytoremediation System

Water chestnuts (Eleocharis dulcis) present an exciting possibility as a core crop within the Ayni Bahay Water Services Cooperative’s water remediation system. Growing water chestnuts in the rainwater circulation ponds offers a dual benefit: producing a nutrient-dense, edible crop while contributing to the water purification process. Since we are dealing with rainwater with relatively low biological oxygen demand (BOD), the phytoremediation system primarily focuses on removing particulate matter, sediments, and minimal chemical contaminants. Water chestnuts, with their low nutrient requirements and adaptability, align well with this goal.

Water Chestnuts (Photo Credit: Canva Pro)

6.1. Benefits of Water Chestnuts in a Phytoremediation System

Water chestnuts provide a sustainable food source while acting as a natural water filter in the rainwater circulation ponds. Here’s how their integration enhances the system:

Food Production: Water chestnuts are a nutrient-rich crop that thrives in shallow, slow-moving water. They are a staple in many Asian cuisines and offer a reliable, calorie-dense source of carbohydrates, vitamins, and minerals to the cooperative members.
Low Nutrient Requirements: Unlike other crops that may require higher nutrient inputs, water chestnuts can thrive in the nutrient-depleted conditions of a rainwater-fed system, making them ideal for integration into a low-BOD water remediation pond.
Water Purification: Water chestnuts act as a living filter, improving water quality by absorbing nutrients like nitrogen and phosphorus. This reduces the risk of eutrophication (nutrient over-enrichment) and helps maintain a balanced aquatic ecosystem.
Symbiosis with Water Hyacinth: Water chestnuts can coexist with water hyacinth in the same phytoremediation ponds. While water hyacinth provides rapid biomass production for biochar, composting, and pollution uptake, water chestnuts contribute to the system’s food security. Together, they offer complementary functions: water hyacinth cleans the water more aggressively, while water chestnuts contribute to food production and water stabilization.

6.2. Water Chestnuts and Phytoremediation of Rainwater

Rainwater entering the system typically contains low levels of contaminants, such as particulates, atmospheric pollutants, and trace minerals. While these levels are lower than in greywater, phytoremediation is still necessary to ensure that the rainwater is clean and safe for consumption. Water chestnuts help purify rainwater by:

Sediment Capture: The dense root systems of water chestnuts trap suspended particulates and fine sediments, which may enter the water during rainfall or through runoff.
Pollutant Uptake: Water chestnuts absorb low levels of heavy metals, nitrogen, and phosphorus from the water. Their presence in the phytoremediation ponds prevents nutrient buildup, which could otherwise lead to water quality degradation.
Aeration and Oxygenation: Water chestnuts, along with other plants like water hyacinth, help improve the dissolved oxygen content of the ponds, enhancing the overall health of the aquatic ecosystem and contributing to more effective water remediation.

6.3. System Design for Water Chestnut Cultivation

Incorporating water chestnuts into the system requires thoughtful pond design:

Shallow Pond Areas: Water chestnuts thrive in shallow waters (approximately 0.5 to 1 meter deep), so sections of the rainwater circulation ponds should be designed with shallow beds to accommodate their growth.
Intercropping with Other Phytoremediating Plants: Water chestnuts can be intercropped with reeds, cattails, or water hyacinth in adjacent or interconnected pond areas. This ensures a balanced ecosystem where different plants fulfill different roles—some focused on food production, others on biomass generation or water purification.
Pond Rotation: To maintain soil health and prevent plant disease, the ponds may be designed with a rotation system, where some ponds are periodically drained, and plants are harvested, while others continue the remediation process.

By integrating water chestnuts into the rainwater-fed phytoremediation system, the Cooperative can enhance food security while ensuring a continuous supply of clean water for household and agricultural use.

7. Products Made from Water Hyacinth

The water hyacinth (Eichhornia crassipes), besides being a critical element in the water filtration and phytoremediation process, is a valuable resource for producing various eco-friendly products. Utilizing the hyacinth’s fast-growing and extensive biomass helps manage its invasive potential while turning it into productive outputs. This section outlines the different products that can be derived from water hyacinth within the Ayni Bahay Water Services Cooperative.

7.1. Biomass for Compost and Soil Amendment

Composting: Water hyacinth can be directly used as green matter in composting processes. The harvested plants decompose into nutrient-rich organic compost, which can be added to agricultural soil or garden beds. This supports the regenerative agricultural cycle by boosting soil fertility and microbial health.
Worm Castings: When combined with food waste and other organic matter, water hyacinth can be fed to composting worms (vermiculture). The worms break down the hyacinth and produce worm castings (vermicompost), a highly nutrient-dense organic fertilizer. This further enhances soil structure, water retention, and plant nutrient uptake.

7.2. Biochar Production

Pyrolysis: One of the primary uses for harvested water hyacinth biomass in this system is biochar production. Through a pyrolysis process, water hyacinth is burned in a low-oxygen environment, resulting in biochar that is rich in carbon and beneficial for long-term soil enrichment.
Biochar as Soil Conditioner: This biochar can be added to terra preta to enhance soil fertility. Its porous structure retains water and nutrients, fostering an environment rich in beneficial microbes that, in turn, improve the efficiency of phytoremediation plants and the overall water purification process.

7.3. Handicrafts and Textiles

Water hyacinth stems and fibers are widely recognized for their use in handicraft production. The plant’s tough, fibrous structure makes it ideal for weaving into durable, eco-friendly products, offering an economic opportunity for the cooperative:

Basket from Water Hyacinth (Photo Credit: Amazon)

Baskets and Mats: The dried fibers of water hyacinth are traditionally woven into various products like baskets, bags, mats, and furniture. These products can be sold as sustainable crafts, providing income for the community while promoting eco-friendly practices.
Textiles and Paper: The pulp of water hyacinth can also be processed into fiber for paper production or used to create coarse textiles. These eco-friendly materials can be further developed into value-added products like notebooks, packaging, or household items.

Artist Quality Paper from Water Hyacinth (Photo Credit: Amazon)

7.4. Biogas and Bioenergy Production

Anaerobic Digestion: Water hyacinth biomass can be processed in biogas digesters, producing methane that can be used for energy production (cooking gas or electricity generation). This helps to harness another renewable energy resource within the system, providing energy autonomy to the cooperative.
Biofuel: With proper technology, water hyacinth can be converted into bioethanol, contributing to energy needs while reducing reliance on fossil fuels.

7.5. Fiber Boards and Eco-Building Materials

Construction Materials: Water hyacinth fibers can be processed and compacted to form fiber boards, which are useful as low-cost, lightweight building materials for furniture, panels, or wall insulation. These materials are highly renewable and help reduce pressure on timber and other traditional resources.
Plywood Substitute: Water hyacinth pulp can be mixed with resin or natural binding agents to produce plywood alternatives, offering another form of sustainable construction material.

8. The Role of Terra Preta in Enhancing the System’s Circularity

Terra preta, or “dark earth,” is a highly fertile type of soil that originates from the Amazon basin. It is created by enriching soil with a combination of biochar, organic matter, and nutrient-rich compost. In the context of the Ayni Bahay Water Services Cooperative, terra preta plays a critical role in regenerating the phytoremediation ponds, improving plant health, and sustaining the system’s circular nutrient cycle. This section explains the key functions of terra preta and its importance in maintaining vibrant plant growth for clean water production.

8.1. Nutrient Retention and Bioavailability

Biochar’s Role in Terra Preta: Biochar is a core ingredient in terra preta, acting as a highly porous carbon structure that traps and holds nutrients, water, and organic compounds. By continuously replenishing the phytoremediation ponds with fresh biochar from the biomass of water hyacinth, terra preta helps maintain high levels of nutrient availability for the plants in the system.

Terra Preta Soil (Photo Credit: Canva Pro)

Increased Plant Growth: Terra preta promotes more vibrant plant growth by improving nutrient retention, which in turn increases the plants’ ability to uptake contaminants and nutrients from the water. This makes the phytoremediation process more effective, as healthier plants have higher metabolic activity and can process a greater volume of greywater.

8.2. Microbial Activity and Soil Health

Beneficial Microbes: Terra preta is rich in beneficial microorganisms that enhance soil fertility by breaking down organic matter and making nutrients more accessible to plants. These microbes play a vital role in the decomposition of toxins, facilitating the breakdown of organic pollutants in the water that enters the phytoremediation ponds.
Increased Biological Diversity: The addition of biochar to the soil creates a habitat for a diverse community of soil microorganisms, fungi, and bacteria. This increased biodiversity ensures that the soil remains healthy, which in turn leads to more resilient plant growth and better water filtration capacity.

8.3. Water Retention and Climate Resilience

Improved Water Retention: Terra preta significantly improves the water retention capacity of soil, which is particularly important in a tropical climate like the Philippines, where alternating periods of heavy rain and drought occur. The high porosity of biochar allows the soil to hold more water during rainy periods, ensuring that the plants have access to water during drier spells.
Buffer Against Drought: With better water retention, the phytoremediation system becomes more resilient to climatic fluctuations, maintaining plant vitality and consistent water purification even during extended dry periods.

8.4. Long-Term Carbon Sequestration

Carbon Capture: One of the defining features of terra preta is its ability to act as a carbon sink. By continually adding biochar from water hyacinth pyrolysis, the system locks away carbon in the soil for thousands of years, effectively reducing the Cooperative’s carbon footprint and contributing to climate change mitigation.
Sustainable Biomass Cycle: The biomass produced from the phytoremediation ponds is transformed into biochar, which is then returned to the soil, creating a self-sustaining nutrient cycle. This constant regeneration of the soil ensures that the plants used for water filtration remain healthy and effective in the long term.

8.5. Role in Phytoremediation

Enhanced Plant Health: Terra preta, enriched with biochar, provides optimal growing conditions for phytoremediation plants like reeds and water hyacinth, as well as for food crops like wild rice. Healthy, nutrient-rich soil increases the growth rate and vigor of these plants, improving their ability to absorb toxins and nutrients from the water.
Cleaner Water: As the plants in the phytoremediation ponds thrive in the nutrient-rich environment of terra preta, they are able to more effectively remove pollutants from the greywater. This results in cleaner water at the end of the filtration cycle, reducing the need for additional mechanical or chemical treatments.

9. Integrated System: Circular Process of Biomass, Biochar, and Terra Preta

The combination of biomass production, biochar generation, and terra preta creation forms the backbone of the Ayni Bahay Water Services Cooperative’s water remediation system. This circular process ensures that the system is self-sustaining, regenerative, and highly efficient in both water purification and soil fertility.

9.1. Biomass Harvesting

Water hyacinth and other phytoremediation plants are harvested regularly from the ponds.
Biomass is processed either through composting or pyrolysis to produce biochar.

9.2. Biochar Production

Pyrolysis: The harvested biomass is heated in a low-oxygen environment, producing biochar while capturing energy as biogas or heat.
Biochar is added back into the system, either mixed into the soil as a soil amendment or used to enrich terra preta.

9.3. Terra Preta Creation

Terra preta is created by mixing biochar with compost, organic waste, and existing soil, creating a highly fertile soil that supports vigorous plant growth.
Terra preta is periodically applied to the phytoremediation ponds to replenish the growing medium for the water filtration plants.

9.4. Enhanced Phytoremediation

The vibrant, healthy plants in the terra preta-enriched soil filter the greywater, absorbing toxins, nutrients, and contaminants.
The cleaner water is then recirculated back into the system, providing clean water for washing, cooking, and cleaning.

10. Community Benefits of Cooperation Around Water Infrastructure

At the heart of the Ayni Bahay Water Services Cooperative’s mission is the principle of symbiosis—between people, nature, and infrastructure. Water is not only essential for physical health but also for building community well-being. A cooperative approach to water infrastructure, where everyone has a role in managing, maintaining, and benefiting from the system, fosters a deeper sense of shared responsibility and mutual support. This section highlights the broader community benefits of such a system, with water at its core.

10.1. Health and Wellness: Clean Water as a Foundation

The most immediate benefit of a community-managed water system is access to safe, clean water. This improves overall community health by reducing the incidence of waterborne diseases, ensuring that water is available for drinking, cooking, cleaning, and sanitation.

Access to Potable Water: The closed-loop, phytoremediation-based water system guarantees a steady supply of potable water, free from contaminants. This means fewer illnesses related to poor water quality, reduced healthcare costs, and a healthier population.
Safe Greywater Management: Greywater from household use is effectively recycled through the system, minimizing pollution and ensuring that water is not wasted. The system encourages the use of environmentally friendly soaps and cleaners, reducing chemical pollutants and ensuring the long-term sustainability of the water cycle.

10.2. Food Security: Water Infrastructure Supporting Agriculture

Beyond water, the system’s integration with food crops—like water chestnuts—helps ensure local food security. Phytoremediation plants, besides purifying water, also provide opportunities for growing crops that are nutritious and abundant.

Water Chestnut Cultivation: By incorporating water chestnuts and other crops into the pond system, the cooperative not only addresses water needs but also produces sustainable food sources that benefit the entire community.
Local Food Production: The cooperative model promotes the use of community-managed land and water resources for growing food, ensuring that the community has direct access to fresh, locally grown produce. This reduces dependency on external food sources and fosters a resilient local food economy.

10.3. Economic Benefits: Job Creation and Product Development

The cooperative water system also serves as a catalyst for economic activities:

Job Creation: Managing the water filtration system, harvesting biomass (such as water hyacinth and water chestnuts), and producing byproducts like biochar or handicrafts from water hyacinth fibers creates jobs within the community.
Handicrafts and Eco-Products: Water hyacinth, in particular, is valuable for producing sustainable handicrafts, furniture, and textiles, offering economic opportunities for artisans and craftspeople within the cooperative.

10.4. Environmental Benefits: Symbiosis with Nature

By focusing on natural processes such as phytoremediation, the cooperative system promotes environmental stewardship. This ensures that the water system not only serves human needs but also enhances the local ecosystem.

Biodiversity Support: The integration of native plant species, including water chestnuts and reeds, supports local biodiversity and provides a habitat for wildlife, including aquatic species, birds, and beneficial insects.
Carbon Sequestration: The production and use of biochar not only improves soil health but also acts as a long-term method of carbon sequestration, contributing to climate change mitigation.

10.5. Social Cohesion: Water as a Symbol of Shared Responsibility

One of the most powerful effects of a cooperative water system is its ability to foster a sense of social cohesion. Water, as a shared resource, becomes a symbol of community interdependence and trust.

Cooperative Participation: Involving all members of the cooperative in the management and upkeep of the system encourages shared responsibility. This creates a sense of ownership and pride in the community’s ability to sustain itself.
Psychological Well-being: Access to clean water, a regenerative environment, and a stable food supply contributes to the psychological well-being of the community members. Knowing that their basic needs are met through cooperative effort provides a sense of security and mutual support.
Education and Empowerment: The cooperative model emphasizes education and the sharing of knowledge, ensuring that community members understand the processes behind water management, food production, and environmental care. This empowers individuals to take an active role in the long-term health of their community.

10.6. Holistic Well-being: Water as the Basis for a Symbiotic Community

Ultimately, the water remediation system serves as more than just infrastructure—it is the central pillar of a symbiotic community. By addressing both the physical (clean water, food security) and psychological (social cohesion, environmental harmony) needs of its members, the cooperative achieves a holistic model of well-being. This aligns with the principles of Ayni—reciprocity and balance between human beings and nature.

Rufous Hornbill, part of the Phillipines rich biodiversity and world-heritage (Photo Credit: Canva Pro)

Conclusions

By integrating water chestnuts into the rainwater circulation ponds, the Ayni Bahay Water Services Cooperative establishes a more resilient, food-producing water system, strengthening its self-sufficiency and contributing to the community’s health and economy. Together with a cooperative management structure, this system becomes a model for how community-driven water infrastructure can lay the foundation for sustainable living, ecological health, and community well-being.

Incorporating water hyacinth biomass, biochar production, and terra preta into the Ayni Bahay Water Services Cooperative creates a highly efficient, circular system that enhances both water purification and agricultural productivity. This closed-loop system not only provides clean, usable water for the cooperative’s members but also generates valuable products such as compost, biochar, sustainable construction materials, and handicrafts. By continuously recycling nutrients and biomass through the phytoremediation ponds, the system ensures its own sustainability, resilience, and capacity to support the local ecosystem.

The water remediation and biomass management system for Ayni Bahay is a closed-loop, sustainable solution. It provides clean, usable water for 100 people through a carefully engineered phytoremediation process using native and regionally appropriate plants like reeds and water hyacinths. The excess biomass is harvested and processed into biochar, compost, and terra preta, enhancing soil fertility and promoting a regenerative cycle that benefits the community garden and local agriculture.

This system supports the Cooperative’s goals of water independence, ecological integrity, and soil regeneration, ensuring long-term sustainability for the community.

Next Steps

Detailed engineering design of pond layouts, pump systems, and circulation paths.
Plant species selection and sourcing based on local climate and phytoremediation needs.
Community training on ecological soap use and system maintenance.

General References for Further Reading

Phytoremediation and Water Management

Salt, D. E., Smith, R. D., & Raskin, I. (1998). Phytoremediation: Annual Review of Plant Physiology and Plant Molecular Biology. 49, 643–668.
Macek, T., Macková, M., & Kas, J. (2000). Exploitation of plants for the removal of organics in environmental remediation. Biotechnology Advances, 18(1), 23-34.
Reddy, K. R., & DeBusk, W. F. (1985). Nutrient removal potential of selected aquatic macrophytes. Journal of Environmental Quality, 14(4), 459-462.
Vymazal, J. (2007). Removal of nutrients in various types of constructed wetlands. Science of the Total Environment, 380(1-3), 48-65.

Biochar, Terra Preta, and Soil Regeneration

Lehmann, J., & Joseph, S. (Eds.). (2015). Biochar for Environmental Management: Science, Technology and Implementation (2nd ed.). Earthscan.
Glaser, B., Lehmann, J., & Zech, W. (2002). Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal – a review. Biology and Fertility of Soils, 35(4), 219-230.
Steiner, C., Teixeira, W. G., Lehmann, J., & Zech, W. (2004). Long-term effects of manure, charcoal, and mineral fertilization on crop production and fertility on a highly weathered Central Amazonian upland soil. Plant and Soil, 265(1-2), 1-12.
Schmidt, H. P., Pandit, B. H., Martinsen, V., Cornelissen, G., & Conte, P. (2020). Terra Preta: The Role of Biochar in Carbon Fertility Management in the Amazon. Geoderma, 379, 114638.

Aquaculture, Hydroponics, and Reeds in Water Filtration

Rakocy, J. E., Masser, M. P., & Losordo, T. M. (2006). Recirculating Aquaculture Tank Production Systems: Aquaponics—Integrating Fish and Plant Culture. Southern Regional Aquaculture Center, Publication No. 454.
Capon, S. J., & Brock, M. A. (2006). Flooding, soil seed bank dynamics and vegetation resilience of a hydrologically variable desert floodplain. Wetlands Ecology and Management, 14(5), 479-493.
Cronk, J. K., & Fennessy, M. S. (2001). Wetland Plants: Biology and Ecology. CRC Press.
Tronstad, L. M., & Hall, R. O. (2007). Aquatic Macrophytes Control Benthic and Hyporheic Metabolism in a Floodplain River. Limnology and Oceanography, 52(6), 2340-2351.

Water Systems and Community Management

Falkenmark, M., & Rockström, J. (2004). Balancing Water for Humans and Nature: The New Approach in Ecohydrology. Earthscan.
Bell, S., & Morse, S. (2008). Sustainability Indicators: Measuring the Immeasurable? Earthscan.
Blanco-Canqui, H., & Rattan, L. (Eds.). (2015). Principles of Soil Conservation and Management. Springer.