Guide to wastewater recycling in tropical an subtropical regions.
How to plan, build and operate wastewater recycling facilities in warm climates.


Table of content

1.1. Who this Website is for
1.2. Background to Projects

2.0. What is wastewater recycling?
2.1. Inputs, Processes and Outputs
2.2. Possible Site Configurations
2.3. Different Models for Different Conditions

3.0. What is the financial value of wastewater recycling?
3.1. Fees Charged by State Water Agencies
3.2. Market Values of Products Produced on Site
3.3. Estimated Value of Ecosystems
3.4. Summary Calculations of Costs and Benefits

4.1. Project planning steps - getting started
4.2. Social Requirements
4.3. Financial Requirements
4.4. Preliminary Site Selection and Design

5.1. Designing
5.2. Before starting construction
5.3. Construction components (Part 01)
5.3. Construction components (Part 02)
5.3. Construction components (Part 03)
5.3. Construction components (Part 04)
5.4. Troubleshooting
5.5. Example of site layout

6.1. Process for deciding the type of operations
6.2. Products from operations
6.3. When do operations begin ?
6.4. Before you let wastewater in...
6.5. Water flow sequence
6.6. Pathways for solids
6.7. Components and how they work (Part 01)
6.7. Components and how they work (Part 02)
6.7. Components and how they work (Part 03)
6.8. Wildlife
6.9. Safety on site

7.1. Planning Stage (Part 01)
7.1. Planning Stage (Part 02)
7.1. Planning Stage (Part 03)
7.1. Planning Stage (Part 04)
7.1. Planning Stage (Part 05)
7.2. Construction
7.3. Operations Stage
7.4. List of legal documents
7.5. Community involvement and survey

8.0. Related Links

Who this guide is for:

  • Municipalities under-serviced by water companies
  • State water agencies that fail to meet regulatory standards
  • Farmers who need to improve productivity or reduce waste treatment costs
  • Agro-industries looking for byproducts from waste streams
  • Restaurants, hotels, and other complexes requiring wastewater facilities
  • Pollution control and public health agencies
  • Multilateral development agencies
  • Insurance companies looking to reduce liability of clients for pollution
  • Environmental organizations

This guide explains how to integrate wastewater treatment, recycling, and organic agriculture. It uses information from 'Guide to Wastewater Recycling in Tropical Regions', Hansen & Mulhall published by the European Commission in cooperation with Hamburger Umweltinstitut, O Instituto Ambiental, and Aquasol International Ltd. with experts in Brazil, China, Germany, South Africa, and Mauritius.

 For more information:

©Copyright 1998-2008 Aquasol International Ltd., Hamburger Umweltinstitut e.V. & O Instituto Ambiental
DISCLAIMER: This is a guide only - avoid constructing a wastewater recycling facility without expert help.


Actual Situation of the Biomass Project since its Creation in 1991

. 14

 1.   Introduction

Problems related to the inadequate disposal of insufficient treated or untreated wastewater in the environment are well know. Composition of wastewater, make of this a transport route of pathogen, nutrients and different kinds of pollutants. As a contradiction, the increasing worldwide agricultural demand of nutrients for fertilizers production is reaching a critical point due to the depletion of nutrients sources, especially Phosphorus. Intensive agriculture is highly dependent on fertilizers based on phosphate rock which due to its natural radioactivity makes questionable its use for this purpose. According to various scholars (Tweeten, 1989; Fixen, 2009; Smit et al., 2009), phosphate rock will be depleted quite soon, estimated year for depletion range from 2050 to 2100.

To face this situation, other nutrient sources should be considered. Domestic wastewater represents a nutrient source that has a high potential to meet the phosphorus and nitrogen demand for fertilizers manufacturing. In Germany, the Federal Environmental Agency have calculated that approximately 55% of the annual phosphorus demand for fertilizers production would be covered by the phosphorus contained in the sewage sludge (Umwelt Bundesamt, 2013).

Industrialized countries have developed technologies for wastewater treatment which simultaneously separate nutrients from other undesirable compounds seeking the reuse of these nutrients for fertilizers production. Hovewer, nutrient recovery technologies from wastewater need to be improved to achieve the technic and economic viability that allow its application in large scale.

For developing countries, a suitable treatment of wastewater already represent a challenge. Therefore, contemplate the implementation of specific technology for nutrients separation and subsequent disposition in fertilizers, is unreacheable. Moreover, in areas of extreme poverty, adquisición of fertilizers and acces to suitable water sources for irrigation is extremely difficult. Therefore, low-resource areas often draw on untreateed wastewater for irrigation purposes. For example, in Colombia approximately 25,000 ha are irrigated with untreated wastewater meanwhile in Peru 20,000 ha have been reported.

The Biomass Project, launched in 1991, was developed as an innovative technology seeking to face the challenges of wastewater treatment exploiting simultaneously the nutrient content for agricultural and biomass production.  Managed by the Hamburger Umweltinstitut in Germany in coordination with the O Instituto Ambiental in Brasil, the project was partially financed by the European Community and was completed in 1998. The Project was initially implemented in four locations in Brasil and China.   

The project has been extended, and main goal of this report is to compile and analyze data of the actual status of the facilities. The information presented below summarizes the actual situation of the project since its implementation in 1991 in Brasil (Silva Jardim) to its current status in Haiti, Nicaragua and Dominican Republic.


2.   Status of the Biomass Project in Brazil, Haiti, Nicaragua and Dominican Republic

2.1. Stand: Silva Jardim - Rio de Janeiro - Brazil

 2.1.1. Location: Cidade Nova – Municipality Silva Jardim

           2.1.2  Technical Information of the Facility:

a)    Process Description: Facilities are designed depending on the objectives of the process, this means that depending on the effluent quality required, the standards of the treatment will be defined. In Silva Jardim the main goal is to use the nutrient content of wastewater for fertilization purposes in compliance with the specific effluent standards related to this use. In Silva Jardim the system consists of:

1.    Pre-treatment underground basin

2.    Biodigestor: Reduction of 70% of the organic material content, stabilization of the influent and biogas production.

3.    Biological filter systems: Retention and degradation of the remaining organic material from the biodigestor.

4.    Settlement/oxidation basins: Solids retention, algae production, nutrients conversion, neutralization of pathogens and BOD reduction. These basins may include aquaculture production.

5.    Macrophyte ponds: Nutrients conversion, shallow systems with higher exposure to sunlight and extent retention time which consequently would result in pathogens elimination.

6.    Garden areas produce agricultural products.

b)    Wastewater Characteristics: Some characteristics of the wastewater are used as indicators to monitor the adequate performance of the system. Variations in the quality and amount of the influent may affect the biological and biochemical processes involved in the treatment. With this purpose, basic data related to wastewater quality should be recorded. Such data include influent flow (m3/month), BOD5 (mg/l), COD (mg/l),  Ptotal (mg/l), Ntotal (mg/l), pH, OD (mg/l).

Some water quality data of the effluent was published in a video material of OIA (O Instituto Ambiental, 2018)

Table 1: Quality of the effluent in the facility Silva Jardim and such published by the European Community for Urban Waste Water Treatment Plants (Council Directive 91/271/EEC concerning urban waste water treatment)

Source BOD5 (mg/l) Ptotal (mg/l) Ntotal (mg/l)
Silva Jardim effluent 7 1.5 4
European Standards 25 2 15


      c)    Total population served: Monitoring the population size connected to the system is needed to have a clear idea about the stability of the system over time. An increase in population size may be a sign that the demand of the system have  increased, in which case, it would be possible to take the adequate measures to cover the new treatment demand. According to the available data in the HUI Portal (Chapter 3.1) approximately 800 inhabitants are benefit from the system and the amount of wastewater treated would be 4 200 m3/month. These are estimations based on the data of Sabesp (largest wastewater state agency in Brazil).


2.1.3. Stakeholders: Depending on the stage of the project the stakeholders may change. For Cidade Nova – Silva Jardim, a stakeholder’s structure are shown in figure 1.     




 Figure 1. Stakeholders of the Biomass Project performed in Cidade Nova – Municipality Silva Jardim - Brazil until 1998.


2.1.4.Benefits: Benefits achieved thanks to the Biomass Project may be grouped in:

·         Development and land use efficiency

·         Environment

·         Finance

·         Health

·         Science

Benefits related to the productivity of the system, whether productivity may be reported as biomass production or as net monetary benefits, may be used as tools to monitor the stability of the system. Once a facility has reached maturity, as the case observed in Silva Jardim, it should have accumulated sufficient statistical data to monitor productivity fluctuations. In case of productivity depletion, causes of it may be identified and appropriate strategies proposed seeking to achieve the sustainability of the system over time.

For Silva Jardim, summarized data are shown in the Hamburger Umweltinstitut Portal (Hamburger Umweltinstitut, 2018).

 Table 2. Total Annual Productivity of the Silva Jardim Facility corresponding to the season 1997 - 1998

Total Annual Productivity of Site




Amortization and operation of a wastewater treatment facility 



Market values of products produced from the site 



Estimating values of ecosystem services 



Total Annual Productivity / ha


Table 3. Total Annual Site Costs expended in the Silva Jardim Facility during the season 1997 – 1998.   



Amortization – facility costs $ 30,000 to construct, amortized over a standard period of 10 years 3,000


Operator Salary and Benefits



Electricity, Maintenance, Equipment Replacement






Seeds & Supplies



Total Annual Site Costs

- 12,500

Leaving aside the estimating values of ecosystem services, as this not reedits cash benefits, the net monetary benefits produced per hectare per year was $ 4,823. Using monetary benefits to monitor the stability of the system would be less suitable than using biomass production. In Silva Jardim factors outside productivity did not let that the products obtained be translated into economic benefits. Domestic consumption and losses due to theft are some of these factors that not permit to reach real calculations of the potential economic benefits of this system.


 Below, data related to the status of the following projects were obtained in the OIA website (O Instituto Ambiental, 2018)


 2.2.        Actual Stand: Sertão do Carangola

 2.2.1.   Location: Sertão do Carangola – Petropolis – Rio de Janeiro

 2.2.2.   Technical Information:

a)    Total Population Served: 200 families, childcare facility and community center.

b)    Process Description:

·         Biogas produced is used for cooking in the community center.

·         The nutrient recycling system receives sewage of 200 families. After passing a screening system the sewage is discharged in an underground sedimentation tank (sewage stabilization). Two oxidation tanks continue the treatment with the support of microalgae. Effluent is discharged in a fish pond and after that five tanks of macrophytes provides the last uptake of nutrients that allowed the effluent to be discharged in an adjacent river. Macrophytes biomass is used for composting that finally benefits the vegetal production in garden.

 2.2.3.   Stakeholders:

  • Seop (Service for Education and Popular Organization)
  • Municipality of Petropolis
  • Association of Residents of Sertão do Carangola
  • Dr. João Carlos de Almeida Braga (Benefactor)
  • HUI – Hamburger Unweltinstitut e. V.
  • Aqua Sol International
  • European Community

 2.2.4.   Current Management: Actually, the facility operates under the responsibility of the residents.


 2.3.        Actual Stand: San André – Brasil

 2.3.1.   Location: Santo André - Distrito de Cabralia – Bahia - Brazil

 2.3.2.   Technical Information:

a)    Total population served: 90 school children and 800 persons as fluctuating population

 2.3.3.   Stakeholders:

  • Ecopavi
  • Local Entrepreneurs
  • Municipality of Cabrália
  • OIA

  2.4.        Actual Stand: Bituruna – Brazil

 2.4.1.   Location: Municipality of Bituruna – Parana – Brazil

 2.4.2.   Technical Information:

a.    Total population served: 100 inhabitants

b.    Process description: Biodigestor feed with sewage of 100 inhabitants. Biogas used for cooking. Effluent of the biodigestor discharges into a macrophyte pond. The biomass produced is used in composting to fertilize the municipal garden. Effluent of the macrophyte pond aimed for irrigation of tree shoots. 

 2.4.3.   Stakeholders:

  • Escola Família Agrícola (EFA) de Bituruna
  • Municipality of Bituruna
  • Municipality of Porto Vitória
  • União da Vitória University – Uniguacu
  • Emater Regional do PR.

 2.5.        Actual Stand: Araruama - Brazil

 2.5.1.   Location: Araruama - Rio de Janeiro - Brazil

 2.5.2.   Technical Information: The wastewater treatment plant Ponte dos Leites built during the 1990s works as an aeration basin complemented by the treatment capacity of a root wastewater treatment basin. OIA was consulted to provide its expertise in designing the structure of this complementary system, obtaining very good results thanks to by-products of the treatment process, stabilization of the treatment performance and a notable energy savings in relation to former consumption in the wastewater treatment plant.   

a.    Total population served: 125,000 Inhabitants

b.    Technical Information: Effluent from the aeration reactor discharges into different basins provided with 30 different species of plants which includes Cyperaceous and other macrophytes.

 2.5.3.   Stakeholders:

  • Sanitation Agency of Niteroi e Juturnaiba
  • OIA
  • Artisan local organizations

 2.5.4.   Benefits

  • Biogas production
  • Utilization of papyrus fibers in the manufacturing of craft products.
  • Commercial production of organic compost thanks to macrophytes biomass.
  • Before installation of the root wastewater treatment basins, a company provider of electric energy (ECONOMIZOU) invested in additional aerations systems to avoid the bad odor inherent to the insufficient performance of the wastewater treatment process. Once the plants basins were installed this energy consumption dropped approximately ten times.

 2.6.        Actual Stand: Viva Rio No Haiti

 2.6.1.   Location: Barrio de Belair – Port au Prince - Haiti

 2.6.2.   Technical Information: The brasilian NGO Viva Rio, which up until now still developing a project of cultural-socio-environmental integration in Port au Prince, invited OIA to participate in the implementation of the first biomass project in Haiti. Since the beginning of the project in 2009 until 2012, it has been reported 50 replicates of the system financed by the UN, purifying wastewater of approximately 100,000 inhabitants. Additional benefit of the replicates is the production of biogas.

a.    Total population served at the beginning of the project: 1000 inhabitants

b.    Process Description: Biodigestors, fish ponds and garden areas.

 2.6.3.   Stakeholders:

  • Viva Rio
  • Norwegian government
  • Local agents of development
  • OIA
  • Brazilian army

 2.6.4   Benefits

  • Biogas (50 m3 biogas / day / biodigestor) used for cooking in a community center.
  • Biolosids used in fertilization of forest garden.
  • Effluent used for garden irrigation and in toilets.
  • Micro-enterprises creation (composting, recycling and plant nursery companies) in the PauP region.

 2.6.5.   Current Management: Currently the facility operates independently of OIA (Viva Rio No Haiti, 2017)


   2.7. Actual Stand: Matagalpa – Jinotega - Managua

 2.7.1.   Location: Cities of Matagalpa, Jinotega and Managua in Nicaragua

 2.7.2.   Technical Information: Initially the project was designed to produce shade coffee in a sustainable manner. Actually, almost all the sewage of the hulling process is treated in biodigestors and the problem of the direct discharge of the effluent into rivers is solved.

·         Total population served: 1,000 households, approximately 5,000 inhabitants

·         Process description: Biodigestors treat sewage from the coffee hulling process of various coffee plantations.

 2.7.3.   Stakeholders:

·         State Street Coffee

·         State Street Nicaragua

·         Santa Emilia State

·         Farm “El Chile”

·         La Bastilla

·         Santa Rita

·         Pueblo Nuevo

·         University of Managua

 2.7.4.   Benefits:

  • Biogas production: 1,200 m3/day used in:
  • Electricity production
  • Cooking for the plantation workers


  2.8.        Actual Stand: Jarabacoa - Dominiquen Republic

 2.8.1.   Location: Jarabacoa - Dominiquen Republic

 2.8.2.   Technical Information: The States Agency for International Development (USAID) supported since 2003 local coffe producers to cultivate a better quality coffee based on environmental sanitation. In 2005 local authorities contacted OIA to implement an environmental program in Dominiquen Republic.

·         Total population served: No accurate data

·         Process Description:  Biodigestors treat sewage from coffee plantations.

 2.8.3.   Stakeholders:

·         Coffe producers - Cluster of Jarabacoa

·         USAID

·         State Street Nicaragua

 2.9.        Actual Stand: Caxixe - Brazil

 2.9.1.   Location: Caxixe - Venda Nova do Imigrante - Venda Nova - Espirito Santo - Brazil

 2.9.2.   Technical Information: This project is located in an ecoturist area in the Blue Stone region. Launched and funding  as a private company initiative was later gestioned by state and municipal goverments. The monitoring of the facility was in charge of FAESA University and OIA. The last phase of the project was financed by the program Petrobras Ambiental. Based on the last information published, the project management is carried out by the Prefeitura de Venda Nova do Imigrante.

·         Total population: Approximately 500 Inhabitants

·         Process Description: System is composed of two biodigestors of 40 m3 each one of them, one biofilter of 40 m3,  a root wastewater treatment basin of 125 m3, an algae pond of 60 m3, a fish pond of 1500 m3, nine macrophyte ponds of 180 m3 and a garden area with cultivation of fruit trees and Bambu.

 2.9.3.   Stakeholders:

·         Private company QUIMETAI

·         State secretary for agriculture and fishing

·         Municipality of Venda Nova do Imigrante

·         Association of Residents of Caxixe

·         FAESA University

 2.9.4.   Benefits:

  • Biogas used in a child care center
  • Effluent used in hydroponic crop irrigation, soil irrigation, fish pond.
  • A poultry farm associated to fish pond.


 2.10.        Actual Stand: Sustainable management project of OIA to Mage - Brazil

 2.10.1.    Location: Mage - Baixada Fluminense of Rio de Janeiro

 2.10.2.    Technical information: The project signed in 2003 pursued the integration of the following ecological conservation areas:

·         Private Reserve of Natural Heritage: “Querencia” and “Nagual”

·         Environmental Protection Area: Petropolis

·         National Park: Sierra de Organos

·         Mangroves of Guanabara Bay

The proposal was provided by OIA and the funding by BID – IBAMA 

·         Total population: No accurate data

·         Process description: No description

 2.10.3.     Stakeholders:

·         Brazilian Environmental Ministery

·         BID / IBAMA Federal Goverment

·         OIA

·         Biol. José Carlos Marques (Project Manager)

·         Francisco Pontes de Miranda Ferreira (OIA - Broadcasting Director)

  2.11.     Actual Stand: Conceicao do Surui - Brazil

 2.11.1. Location: Surui - Baixada Fluminense - Nova Iguacu - Rio de Janeiro - Brazil

 2.11.2. Technical information: Facility constructed next to the Center of Integrated Agro Ecological Education (CEIA) - Agriculture School of Mage.

·         Total population: Aprox. 300 inhabitants

·          Process Description: System is composed of a biodigestor with a buffer tank, a biofilter, two oxidation ponds, a macrophyte pond and a garden area.

 2.11.3. Stakeholders:

·         Agricultural School of Mage

·         Secretary of State for Education of Rio de Janeiro

·         Geoscience Laboratory of the Federal University of Rio de Janeiro

·         OIA


  • Effluent used in crop and flower cultivation
  • Biogas used to illuminate the biodigestor area


 2.12.     Actual Stand: Multi Residential Project in Itaipava - Brazil

 2.12.1. Location: Residential area in Itaipava – Petropolis - Rio de Janeiro - Brazil

 2.12.2.Technical Information: Project proposed by the property owners of the residential area.

·         Total population: 400 Inhabitants

·         Process Description: System is composed of five biodigestors, a root wastewater treatment basin, a macrophyte pond, a fish pond and a garden area.

 2.12.3. Stakeholders:

  • Owners of a residential area in Itaipava
  • OIA


  • Biogas is used as principal energy source for cooking
  • Effluent used in garden area.
  • Protection of the Manga Larga River Basin, which is the second principal spring in Itaipava and at the same time, is interconnected with the natural reserve of Araras.  


Details of the following project are taken from a press source published on the OIA website (O Instituto Ambiental, 2009).

 2.13.     Actual Stand: Bonfin Community - Brazil

 2.13.1. Location: Bonfim Community - Petropolis - Rio de Janeiro - Brazil

 2.13.2. Technical Information: The project started in 2006 thanks to private initiative and the OIA participation. According to the publication the company Aguas del Emperador was the main found provider and the project was designed to treat domestic wastewater. The case of Bonfin Community is exposed in this section but it is worth to mention that up to 2009 this system has been extended to treat the wastewater of approximately 10,000 inhabitants in Petropolis. A further emerging aspect is that according to Aguas del Emperador, which invested around $139,269 in 32 biodigestors, no economic return was recorded for the company.

·         Total population: 500 Inhabitants

·         Process description: Two biodigestors

 2.13.4. Stakeholders:

  • Company Aguas del Emperador
  • OIA
  • Bonfin Community

 2.13.5. Benefits:

  • Sanitary benefits related to wastewater treatment. According to the Prefecture of Petropolis, from the installation of this biodigestors, hepatitis cases in this area decreased in 30%.   
  • Biogas provides a household with energy for cooking.


  3.   Conclusions

The initial project, designed to serve to 600 inhabitants, provided the basis for the project implementation in Dominiquen Republic, Haiti, Nicaragua and other locations in Brazil. Actually, after 27 years of its fundation, a total population served of approximately 138,000 inhabitants may be estimated.

This expansion capacity appears encouraging for future implementations but other data besides the spread of facilities is also necessary to know how effectively these installations pursued its goals.

As was previously described, goals of the Biomass Project were the treatment of domestic wastewater in an Integrated System able to harmonize the production of crops and livestock. From these goals, some indicators of effective functioning may arise. Whether the production of crops, livestock or biogas as well as the performance of the treatment process may serve as points of reference related to the proper functioning and sustainability of the project. A deeper evaluation of this indicators still remains for the future.


 4. References





  • Umwelt Bundesamt. (2013). Klärschlammentsorgung in der Bundesrepublik Deutschland. Dessau-Roßlau: Umweltbundesamt (UBA).