HANI SHUBAIL

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DEGREE PROJECT IN THE ENVIRONMENTAL ENGINEERING AND SUSTAINABLE INFRASTRUCTURE, SECOND CYCLE, 30 CREDITS STOCKHOLM, SWEDEN 2020

Assessment of on-site wastewater treatment systems in unsewered communities in Jordan

HANI SHUBAIL

KTH ROYAL INSTITUTE OF TECHNOLOGY

SCHOOL OF ARCHITECTURE AND THE BUILT ENVIRONMENT

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TRITA-ABE-MBT-20728

www.kth.s ewww.kth.s e

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Assessment of on-site wastewater treatment systems in unsewered communities in Jordan

Supervisor

Sahar Dalahmeh, PhD

Department of Energy and Technology, Swedish University of Agricultural Sciences

Email Sahar.Dalahmeh@slu.se

Elzbieta Plaza, (Prof.)

Water and Environmental Engineering,

Department of Sustainable Development, Environmental science, and Engineering (SEED),

School of Architecture and the Built Environment (ABE) KTH Royal Institute of Technology Stockholm, Sweden

Examiner

Elzbieta Plaza, (Prof.)

KTH ROYAL INSTITUTE OF TECHNOLOGY

SCHOOL OF ARCHITECTURE AND THE BUILT ENVIRONMENT

Department of Sustainable Development, Environmental Science, and Engineering SE-100 44 Stockholm, Sweden

Hani Shubail Shubail@kth.se

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Summary in Swedish

För att täcka centraliserade avloppsreningssystems drift och underhåll är det kapitalinsättningen av stor betydelse, förutom högkostnadsprogram, något som anses vara olämpligt för låginkomstländer. In-situ avloppsreningssystem verkar vara en lovande lösning till detta. För att dock säkerställa att dessa ej belastar den omgivande miljö och fungerar som det skall i förbehåll att dessa ständigt övervakas. Konstruerade våtmarker är en typ av in-situ vattenreningsteknik.

Dessa system är lämpliga för småstäder, bergiga och tätortsområden. Dessa system är kostnadseffektiva och flexibla vad dess implementering och hantering anbelangar. Två dylika system är i fokus av denna studie, nämligen två konstruerade våtmarker i Sakib - Jerash i Jordanien och i synnerhet utforskas dess prestanda, social acceptans i och dessutom utfördes en nyttokostnadsanalys. Båda våtmarkerna i denna rapport har konstruerats med ett vertikalt markflöde och är i drift sedan januari 2020 och juli 2015 respektive.

Dessa två system ger goda reduktioner med avseende på biokemiskt syrebehov och kemiskt syrebehov (BOD, COD), totalt suspenderat material (TSS), och effektivitet rörande patogen borttagning (TC och E. coli). Även om patogen borttagningseffektivitet i sig var hög förblev patogenhalt hög i det lokala direktivs avseende; de lokala förutsättningarna, nämligen designparameter och belastningsförhållanden, tillåter dock uppbyggande och drift av dessa två systemen som i fokus i detta studium. Beträffande borttagning av näringsämnen visade det sig att båda systemen har låg kväve- och fosforborttagningseffektivitet. Vissa förslag och rekommendationer föreslogs för att förbättra näringsämnen samt systemens effektivitet vad gäller patogenborttagning; i synnerhet dessa förslag beträffar pumpa ut slammet ur septiktanken, utbyte och backspolning av vattenfiltermedia, vattenväxterinförande eller tillägg av en extern kolkälla samt användning av en ytterligare aerobfiltreringsenhet vid utlopp. Det visade sig att det jordanska samhälle sätter käppar i hjulet vad gäller implementering av dessa våtmarker emedan dess förfarande är oacceptabelt. Dylika problem kan överbryggas genom full insyn, föredrag och workshops samt allmänhetens deltagande. Det sistnämnda gav upphov till en ökad känsla av äganderätt robust, något som ledde till ökat intresse för ansvar i drifts- och underhållsfrågor. Vad nyttokostnadsanalysen anbelangar visade det sig att implementering av ett dylikt system skulle vara fördelaktigt och värdefullt som alternativ för kluster på tätorts- och landsbygdsområden.

Avloppsvattenbehandlingen med lermineraler verkar hittills vara en lovande metod vid betraktande av tidigare studier. Det behöver dock göras ytterligare undersökningar för avloppsvattenbehandlingen med lermineraler vid bestämmande av den optimala lermineral koncentration och dess exponeringstid.

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Abstract

Centralized wastewater treatment systems need substantial funds besides high-cost operation and maintenance programs, which could be considered unsuitable for low-income developing countries. As a solution, it becomes the trend towards on-site wastewater treatment systems (OWTs) due to its cost-effectiveness and flexibility of implementation and management.

However, the keenness to implement these systems appropriately and monitor them continually is crucial to ensure that they do not impact the surrounding environment and human health.

Constructed wetland is one of the on-site wastewater treatment systems. These systems are comparatively affordable alternative technology, and adequate systems for small communities, rural, and hilly areas. In the present study, two constructed wetlands as on-site wastewater treatment systems in Sakib - Jerash Governorate, Jordan, were investigated regarding systems performance, social acceptance, and cost-benefit analysis. The first system is a vertical flow constructed wetland (VCW) that has been operating since January 2020. The second system is a recirculation vertical flow constructed wetland (RVCW) that has been in operation since July 2015.

The checking of the theoretical design parameter and the actual loading conditions of the septic tanks and wetlands in both systems showed that both implemented septic tanks and the wetlands are adequate and appropriate for the design goals. The wetlands’ treatment performance showed sufficient capability in organic matter removal efficiencies: Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD), and Total Suspended Solids (TSS) removal efficiency.

For pathogens: Total Coliform (TC) and Escherichia coli (E.coli), even though the removal efficiency was high, the effluents' values exceeded the local directive. Concerning nutrients removal, both systems showed low nitrogen and phosphorus removal efficiencies. Some suggestions and recommendations were proposed for improving nutrients removal and pathogen removal efficiencies. These recommendations were in desludging the septic tanks, replacing the filtering media, introduce plantation or add other carbon sources to the system, and using an additional aerobic filtration unit in the wetlands’ outlets. The study showed that the Jordanian society's nonacceptance of the on-site wastewater treatment systems could be handled through full transparency, educational workshops, and public participation. The latter contributed an increased sense of ownership robustly and increased concern of responsibilities on the operational and maintenance matters. Regarding the cost-benefit analysis, the study results demonstrated that the implementation of a constructed wetland as an on-site wastewater treatment system could be a beneficial and valuable alternative for clusters in rural areas and even in newly urbanized plans.

The promising method for the treated wastewater's disinfection using clay minerals needs further investigation to determine the optimum clay mineral concentration on treatment and the needed time for exposure.

Keywords

Constructed wetland — Decentralized wastewater treatment — Jordan — On-site wastewater treatment system.

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Acknowledgments

The author has to thank God Almighty, the Most Gracious, the Most Merciful, who deserves the praise for successfully and peacefully giving the author the ability to complete this dissertation.

First and foremost, the author has to express the sincerest gratitude to the supervisor, Dr. Sahar Dalahmeh, from the Swedish University of Agricultural Sciences (SLU), Department of Energy and Technology. Without Dr. Sahar's instructions and guidance throughout the entire thesis period, the author would not improve the research capability to get the outcomes of this dissertation. The continuous follow-up to all novelties during the study and endeavor to overcome all difficulties and obstacles faced by the author was real support and encouragement.

Likewise, the author expresses the gratefulness thanks to Prof. Elzbieta Plaza, Department of sustainable development, environmental science, and engineering (SEED), KTH, for granting the author the trust and the acceptance to examine this thesis.

The author presents appreciation for Dr. Moayied Assayed, Head of Division of Water Studies, Royal Scientific Society (RSS) for the helpful discussion, and insightful suggestions. Besides, for giving the author the chance to use the RSS physical and chemical laboratory to conduct the thesis's required tests. Special thanks to Eng. Mohammed Mashatleh, member of water studies division, RSS, for the continuous readiness to provide the author with the needed tools and instruments for sampling and carrying out laboratory testing. The tremendous support from Dr.

Moayied and Eng. Mohammed during experimentation, analysis, and characterizations was indescribable.

The sincere appreciation is given to Dr. Jwan H. Ibbini, Assistant Professor, Department of Land Management and Environment, Faculty of Natural Resources and Environment, Hashemite University (HU), and Dr. Jwan's assistant, Eng. Mais Thaher for, the real support and cooperation, to secure the author's access to the HU's biological laboratory to conduct the dissertation's biological tests. From Dr. Jwan and Eng. Mais, the author got continuous inspiration, care, and support.

Special thanks to the author's collage Spyridon Xenos for the contribution in translating summary into Swedish.

Finally, the author gives gratitude to beloved parents for continuous prayer throughout the study.

Finally, the author wants to admit that without the sincere support and sacrifices made by the lovely wife, Sarah Al-Serri, the author would not be the person the author is today.

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List of figures

Figure (1) Location of study cases of wastewater treatment systems of septic tank followed by wetland wastewater (Sakib 1 and Sakib 2) in Sakib village – Jerash- Jordan

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Figure (2) Illustration of wastewater treatment components in Sakib 1, which included the wetland (A), the septic tank (The modified septic tank previously) (B).

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Figure (3) The schematic diagram for the septic tank followed by CW in Sakib 1. 10 Figure (4) Illustration of wastewater treatment components in Sakib 2, which included the

wetland (A), the septic tank (B) the splitter (C) and the storage tank (D).

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Figure (5) The schematic diagram for the septic tank followed by RCW in Sakib 2. 12 Figure (6) The average concentration of (A) biochemical oxygen demand BOD5, (B)

chemical oxygen demand COD, and (C) total suspended solids TSS in the influent and effluent of wetlands in Sakib 1 and Sakib 2.

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Figure (7) The average concentration of (A) nitrate NO3, (B) total nitrogen TN, and (C) phosphorous PO4 in the influent and effluent of wetlands in Sakib 1 and Sakib 2.

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Figure (8) The E.coli average measurements for both systems' influent and effluent. 28

Figure (9) The HQ40D Portable multimeter. 41

Figure (10) The DR1900 Portable VIS Spectrophotometer. 42

Figure (11) The Digital Reactor Block 200 (DRB 200). 42

Figure (12) The BD 600 apparatus. 43

Figure (13) The Masterclave 528. 43

Figure (14) Sampling for laboratory tests. 61

Figure (15) A side of laboratory output. 62

List of tables

Table (1) The standard values for both reclaimed water for discharge into torrents, valleys, or bodies and water reuse for irrigation.

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Table (2) The laboratory measured parameters, test methods, kits names, standards methods, control solutions, and apparatus.

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Table (3) The calculated theoretical design parameter and actual loading conditions of the septic tanks and wetlands.

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Table (4) Summary of the measured laboratory tests for the system in Sakib 1. 20 Table (5) Summary of the measured laboratory tests for the system in Sakib 2. 20

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Table (6) Calculations of significant cost components. 30

Table (7) Calculations of significant monetary benefits. 31

Table (8) The operational characteristics of the HQ40D Portable multimeter. 41 Table (9) Test sample volumes and nitrification inhibitor dosage according to BOD5

range value.

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Table (10) The Idexx tables for quantifying bacteria indicators (TC, E. coli, and Pseudomonasaeruginosa).

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Table (11) The Microbial test calculations' and results' tables on 04/03/2020. 53 Table (12) The Microbial test calculations' and results' tables on 08/03/2020. 53 Table (13) The Microbial test calculations' and results' tables on 16/03/2020. 54 Table (14) The contractor pricing on the systems' tendering. 54

List of abbreviations and symbols

BOD5 Biochemical oxygen demand COD chemical oxygen demand CWs Constructed wetlands EC Electric conductivity E. coli Escherichia coli DO Dissolved oxygen

HFCW Horizontal flow constructed wetland HLR Hydraulic loading rate

HRT Hydraulic retention time HU Hashemite University

KM Kilometer

KTH Royal Institute for technology MPN Most probable number NO3- Nitrate

OLR Organic loading rate

OWTs On-site wastewater treatment systems PE People Equivalent

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VIII PO4- Phosphorous

RSS Royal Scientific Society

RVFCW Recirculation vertical flow constructed wetland SLU Swedish University of Agricultural Sciences

SEED Department of sustainable development, environmental science, and engineering TSS Total suspended solids

UHR Ultimate high range ULR Ultimate low range

USEPA United States Environmental Protection Agency VFCW Vertical flow constructed wetland

TC Total coliform TN Total nitrogen TP Total phosphorus

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1. Introduction

Lack of sanitation services leads to many diseases that affect public health. Nearly 40% of the world's population lacks basic sanitation (Ritchie & Roser, 2019), and usually, the rural areas have a potential shortage in such services compared to urban areas (Massoud et al., 2009). About 82% of the rural population in developing countries are affected by this issue (WHO, 2015).

According to Van Afferden et al. (2010), any area or settlement has less than 5000 population considers as rural (Van Afferden et al., 2010).

The conventional centralized wastewater treatment systems need adequate funding and appropriate local expertise, making them challenge to be provided in rural areas due to the low population density and dispersion of housing. Consequently, the trend towards decentralized wastewater treatment systems or on-site wastewater treatment systems (OWTs) grows and develops due to its cost-effectiveness and flexibility of implementation and management (Massoud et al., 2009). Furthermore, decentralized wastewater treatment systems are an attractive option in arid countries suffering from drought and limited water resources.

According to different perspectives, several studies provide different definitions for decentralized wastewater treatments or on-site wastewater treatment systems. Van Afferden et al. (2015) defined the decentralized wastewater treatment as a system that collects, treats, and reuses/disposes the treated effluent at its point of generation vicinity (Van Afferden et al., 2015).

The OWTs could be defined as systems that collect the wastewater and do the treatment then discharge the treated wastewater for a property or facility inhabited by 20 persons (Oakley et al., 2010). Another definition by Massoud et al. (2009) that the on-site wastewater treatment system as that decentralized systems which is less resource-intensive. Moreover, it has a more ecologically sustainable form of sanitation that receives wastewater from a house, a cluster, a small commercial facility, and whose wastewater output limits are unknown. These systems are usually simple and low-cost systems that require less maintenance and monitoring. Such simple and cost-effective systems are suitable for small and isolated settlements or villages with low population densities (Massoud et al., 2009).

The OWTs serve to meet the needs of wastewater treatment and facilitate the on-site reuse such as irrigation and work to prevent environmental pollution and related health problems as a result of direct discharge of untreated wastewater to the surrounding environment (Lienhoop et al., 2014).

Van Afferden et al. (2015) added that decentralized wastewater treatment systems allow high flexibility in dealing with growing urban sprawl situations and are considered suitable solutions for challenging topographical conditions (Van Afferden et al., 2015). However, the reliance on OWTs is often needed in areas that depend on domestic drinking water wells, making these treatment systems linked to the spread of several diseases that threaten human life like infection and diarrheal disease. Moreover, the effect on aquatic systems (Schaider et al., 2017), where OWTS is one of the most commonly doubtful sources of fecal pollution of water resources (Carroll et al., 2005). In this sense, the keenness to implement these systems appropriately and under constant monitoring is crucial to ensure that they are persistent and not impacting the surrounding environment and human health (Bradley et al., 2002).

As aforementioned, due to the earnest water scarcity experienced by many countries in the world, water management experts and specialists' concern shifted towards the reuse of treated wastewater for irrigation purposes. More accurately, this shifting has to be at its maximum levels to become a

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valuable alternative than using other water resources and a priority to adapt to the current global situation (Nelson et al., 2008). Thus, this contributes not only to minimize the impacts on the environment and public health instead maximize the farthest reuse of the water as well (Massoud et al., 2009). It is crucial to ensure the quality of the treated wastewater particularly, in countries that suffer from water scarcity, have limited water resources, and consequently use treated wastewater for irrigation (Iasur-Kruh et al., 2010).

Redder et al. (2010) believe that the tendency to reuse the treated wastewater for irrigation is essential wherever there is a shortage of water like in arid subtropical areas of the world.

However, these applications could comprise epidemiological risks, particularly in developing countries that lack the needed financial ability to implement them properly (Redder et al., 2010).

Risks from reliance on the OWTs were associated with either the design's, operating's, or maintenance's programs for these systems, i.e., failing to choose the appropriate technology for the specific wastewater characteristics or the failure of these systems in some processes of treatment (e.g., removal of nutrients or pathogens). Furthermore, the 2002 report of the United States environmental protection agency explained one of the essential reasons for the OWTs performance variance. The responsibility for operating and maintaining the system is often assigned to inexperienced and uninformed owners. Consequently, it could lead to most system failures. Such examples of system failures due to the lack of experience are the accumulation of sludge in the tanks and hydraulic overloading (USEPA, 2002).

Regarding Sweden in this context, Wallin et al. (2013) illustrate that Sweden relies on on-site wastewater treatment systems for around 700,000 permanent rustic residential buildings. Today, half of these on-site wastewater treatment systems are poorly performing compared to environmental and health current legislation. The aging of OWTs in Sweden is one of the significant sources of nutrient loads and water pollution sources where those systems were constructed from the 70s decade and earlier. It is considered that 15% of phosphorus loads to the environment are the result of OWTs. Furthermore, the total emissions of nutrients from OWTs are equal to those from urban wastewater treatment plants, although the number of Swedes who are still dependent on OWTs represents only a seventh of Sweden's total population. In other words, despite the continuous decrease in the Swedish rural population every year, these loads steadily increase from these systems (Wallin et al., 2013).

2. Aim and objectives

The inductive research question for this thesis was, " Could the on-site wastewater treatment systems be an effective alternative to centralized wastewater treatments in low-income countries with limited resources?". For this question to be investigated, the thesis aimed to assess two on-site wastewater treatment systems consist of septic tanks followed with a vertical flow constructed wetlands (CWs). The systems under investigation located in Sakib village in the city of Jerash - Jordan. The first system (Sakib 1) is a vertical flow constructed wetland (VCW) operating since January 2020 as a new system, and its operating's results represent the time- limited performance assessment. The second system (Sakib 2) is a recirculation vertical flow constructed wetland (RVCW) in operation since July 2015. The results achieved from this system represent long-term performance assessment.

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Aspects of assessment in this thesis included the systems performance and operation aspect, the social aspect, and the economic aspect. Accordingly, the objectives of the study were determined as follows:

1. To assess the design adequacy of the septic tanks built in Sakib - Jerash, Jordan, in terms of volumes, sludge storage capacities, and loading rates of the treatment systems.

2. To assess the treatment performance of the two constructed wetlands built in Sakib - Jerash, Jordan.

3. To study the social acceptance of the two constructed wetlands in Sakib - Jerash, Jordan.

4. To analyze the cost-benefit of the two constructed wetlands in Sakib - Jerash, Jordan.

3. Study borders and delimitations

The targeted geographic areas in this thesis were small-scale communities with dispersed dwelling housing systems in Sakib village in the city of Jerash – Jordan. The community is representative of community that are directly dependent on the OWTs due to the financial and technical difficulties related to linking them with the centralized wastewater treatment plants. Due to the limited time of the study period and to ensure having representative samples of the treated wastewater to investigate the treatment quality, the analysis had been intensified and done on a daily basis. Furthermore, the assessment's results will be within the present, and for the near- future time horizon.

The main three delimitations in this thesis will be:

- The assessment is considered a short-term assessment during the spring season. The seasonal variations, temperature differences, and effects of precipitation were not included.

- This study was limited to the assessment of the quality of wastewater treated in the wetland, which effluent was used for irrigation. However, the effects of reusing the treated water on quality of soil, and effects on irrigated crops were not analyzed within the study.

- The parameters included in the wastewater quality analysis were limited to these types which had available reagents, test kits and apparatus.

- The change in the stability of the assessed system's performance under various seasonal conditions and operational modes (hydraulic and organic loads) were not included in the current study.

4. Theoretical background

People living in rural, semi-urban areas, and new dispersed settlements rely on the conventional system (cesspools or cesspits) to discharge wastewater from their properties. Reliance on cesspools/cesspits causes many environmental and health problems besides its impact on the quality of life as a result of:

- When the cesspit is not adequately sealed, wastewater leaks through soil and rock layers and contaminates the groundwater.

- The cesspool needs continuous discharge when constructed on an impermeable rock layer. Moreover, when there is no financial ability to do this, the cesspool is left to overflow, causing odors and spreading of diseases.

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- When tankers draw the cesspool, it is impossible to ensure that this wastewater will be discharged to the places designated for it, as some tankers illegally empty it into the valleys (Lienhoop et al., 2014).

OWTs, as an alternative, have proven effective by providing the necessary service and efficiency, which emulates the efficiency of centralized wastewater treatment systems. Consequently, it becomes indisputably, reliable technology all over the world.

Several treatment technologies could be considered as OWTs. Primary technology, secondary technology, treatment/disposal technology, and dry sanitation systems classify those technologies.

Simple septic tank and Imhoff tank systems are counted as examples of primary on-site wastewater treatment technology. The secondary on-site wastewater treatment technologies like facultative lagoons, anaerobic or aerobic lagoons, sequencing batch reactors, and constructed wetlands (CWs). Subsurface infiltration, trenches, and beds, seepage pits, mounds, and fills are systems that represent the treatment/disposal technology. The composting toilet is an application of a dry sanitation system (Massoud et al., 2009).

Constructed wetlands (CWs) are one of the on-site wastewater treatment systems. These systems are comparatively new and affordable alternative technology in the wastewater treatment field.

CWs are adequate systems for small communities, rural or hilly areas, where centralized wastewater treatment systems are not financially and technically feasible. CWs provide several advantages such as they often use renewable energy sources, usually the mechanical parts not needed, and could be run out with minimum construction, operation, and maintenance costs (Stefanakis et al., 2009; Hang et al., 2016).

The CW system primarily consists of a septic tank and the wetland. The septic tank is used to collect the wastewater and works as a primary treatment unit where it acts as an anaerobic bioreactor or digester for the retained organic matter. Besides, it removes most of the settleable (sludge) and floatable materials (scum) before the influent redirects to the constructed wetland (USEPA, 2002; Leverenz et al., 2010). The partial digestion of the organic solids in the septic tank reduces the sludge and scum volume up to 40% and adjusts the wastewater by hydrolyzing organic molecules for subsequent treatments (USEPA, 2002). For achieving good sedimentation in the septic tank, it is needed to provide a convenient wastewater residence time with quiescent conditions in the tank known as the hydraulic retention time. The septic tank volume, geometry, and compartmentalization are the design considerations to obtain these conditions (Ibid). During the passage and treatment of the wastewater in the septic tank over the years, the layers of sludge thicken and gradually reduce the amount of space available for sewage. Septic tanks should be pumped every 3 to 5 years, depending on the size of the tank and the number of people served to ensure proper system performance and reduce the risk of hydraulic failure (Ibid). Furthermore, for ensuring efficient performance of pretreatment in the septic tank, regular maintenance has to be made. Cleaning of floatable materials and pumping of the sludge is the only septic tank maintenance requirements.

The wetland is the primary unit for treatment, consisting of a specific land area (according to the type of the constructed wetland and proposed objectives of the treatment) containing the filter media. The filter media is divided into layers (mostly three to four layers) of different gravel sizes.

The effluent comes out from the wetland through the installed outlet pipe within the last layer in the filtration media. Two or four vertical pipes installed from the base of the filter media to the top of the wetland known as ventilation risers, which work to facilitate the air penetration into the

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drainage system and the filter media (Nivala et al., 2013). For higher nutrient removal, wetlands could be constructed as a planted system on the filter media's top surface. The effluent from the septic tank, which is the influent to the wetland, is distributed into the wetland through perforated surface or subsurface pipes. By gravity, the water is transported in the system to filter and complete the treatment steps by exposing it to the oxygen and media's bacteria (Leverenz et al., 2010). If the treated effluent is to be used for irrigation, the system's outlet is connected directly to the irrigation distribution pipes or stored in storage tanks for future use. Otherwise, discharged to the nearest surface water source or valleys.

According to their hydrology, there are two central systems of CWs: the free water surface or subsurface. Similarly, according to the water flow direction, the subsurface constructed wetlands could be classified as horizontal (HFCW), vertical (VFCW), or hybrid. Hybrid systems consist of several types of CWs associated respectively to reach higher treatment results and more intricate treatment efficiency, especially for nitrogen and phosphorus removal. The most common hybrid systems comprise VFCW and HFCW systems arranged in a staged path (Vymazal, 2010). CWs of the same types could vary in their features, e.g., planted roots density, hydraulic conductivity, and influent wastewater characteristics according to the constructed wetlands' designated objectives and the prediction of the removal processes (Wu et al., 2016).

The CW's depend on a series of several mechanisms to execute the treatment processes, including sedimentation, filtration, precipitation, adsorption, volatilization, and plant uptake. However, the bacterial/microbial activity is the primary mechanism for the most contaminant removal due to its ability to work under aerobic and anaerobic circumstances (Meng et al., 2014). The bacteria stick with the surface of the CW's media particles and the roots of the plants (if planted constructed wetland), forming a biofilm that works on the essential decomposition and disintegration of contaminants in the wastewater (Iasur-Kruh et al., 2010).

The wetlands' effectiveness in treating the domestic wastewater for the reduction of biochemical oxygen demand, suspended solids has been proven in several studies and could be compared to the conventional centralized treatment (Redder et al., 2010). The limited dissolved oxygen (DO) concentration in the CW's filtration beds represents anaerobic conditions that enhance organic compounds' degradation through microbial degradation. Wetlands have a better rate of biological activity than most ecosystems. This feature is attained by the advantage of the wetland's land area, with the sun's underlying natural environmental energies, media/soil, wind, animals, and plants.

These factors help these systems require minimal energy and chemicals to be operated and meet treatment objectives (Vymazal, 2010).

An efficient wetland system’s design is required to ensure producing high-quality effluent water.

The gravel material used for the filtration media besides the hydraulic flow rate are two significant parameters in CW's design (Iasur-Kruh et al., 2010). Meng P. et al. (2014) illustrated in their study that the media used as filtration beds in the constructed wetland is a vital component not only because of its adsorption capacity for contaminants but also it provides the ideal conditions for microbial growth and plants settlement (if available). The gravel properties, including particle size, surface area, porosity, hydraulic conductivity, pH, and organic matter content, contribute to the microbial mediated processes.

Gravel with a bigger grain size in the upper layer in constructed wetland beds is the significant parameter affecting the performance in suspended solids retention and the mass transformation rate of the oxygen. However, depending on extremely large-sized media should be avoided as the

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top coarse layer's surface area becomes insufficient for the biofilm's growth. Similarly, using too small grains of gravel, e.g., organic soil, can provide a higher specific surface area for biofilm formation. Thus, the exceedingly narrow pore diameters may result in the joining of surface aggregations and pore blocking. The porous media may offer a larger surface area for biofilm growth and increase the interaction area with contaminants in wastewater. Furthermore, using materials rich in organic matter in the filtration beds can supply the needed carbon source to enhance the constructed wetland's microbial processes (Meng et al., 2014).

Zeolitic volcanic tuff is one of the most used media in the constructed wetlands in Jordan. The solidification of ash and other sediments coming out of volcanic vents is what creates the volcanic tuff. Tuff comparatively is a porous rock whose mineral composition is predominantly glass (Geology Science, 2020). The zeolitic volcanic tuff is a soft, lightweight aggregate with a specific gravity of 1.89 kg/m³. The zeolitic volcanic tuff has a good porosity with a value of 60.5%, and the water absorption of 8.7% (Al Dwairi et al., 2018). Volcanic tuff is available widely in the Jordanian land. However, it varies on its mineral content and quantity associated with zeolites based on the weathering rate and zeolitization processes from one location to another (Ibid).

Although CW systems prove their effectiveness in achieving the required treatment, however, they have some secondary cons, such as the need for a relatively large surface area (3–5m² / population equivalent) to be constructed, which makes them not suitable for all conditions (Moelants et al., 2008). Tanner et al. (2012) estimate an area of (4–8 m² per person equivalent) to construct a horizontal constructed wetland (Tanner et al., 2012). Furthermore, the limited aeration and the need for intermittent alternating through media beds to prevent the surface's blocking limit the ingrained usage of these systems (Sklarz et al., 2009). HFCWs are predominantly anaerobic systems as oxygen transportation through the saturated media is limited where transportation is occurring through the planted macrophyte roots in relatively small amounts (Tanner et al., 2012;

Nivala et al., 2013). As a result, the efficiency in eliminating nitrogenous compounds in HFCWs is relatively low (García-Pérez et al., 2009). The trend to the VFCWs enhances the oxygen transfer rate and consequently increases the effectiveness of removing the organic matter and nitrification (García-Pérez et al., 2009; Sklarz et al., 2009). VFCWs have high redox chances to support aerobic microbial processes. On the one hand, a notable higher BOD removal and nitrification results could be gained from VFCWs. On the other hand, lower denitrification has been noticed in VFCWs compared with HFCWs (Meng et al., 2014).

Depending on area topography to use gravity instead of pumping in CWs considering the proper design of the wetland's sidewalls to avoid the overflow is called a passive CW system. Using extensive/passive and natural CW systems, perform better and more robust options than compact/active CW systems. As they require fewer or non-mechanical parts, less energy will be used, and little maintenance will be needed (Moelants et al., 2008; Nelson et al., 2008; Oakley et al., 2010).

For constructed wetlands' performance enhancement, the recirculation had been introduced to the systems to increase both nitrification (via multiple infiltration through the unsaturated beds) and denitrification (via added dosage with carbon-rich influent) (Tanner et al., 2012).

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5. Study area

Jordan is a developing country suffering from severe water scarcity (Van Afferden et al., 2010;

Mayrhauser, 2012). The country ranks as the fifth nation to have the highest water shortage, where rainfall is less than 5 centimeters each year (Whitman, 2019). Climate change (Ibid) and the steady influx of refugees from Syria since 2011 are factors that elevate this problem (Alshoubaki & Harris, 2017; Whitman, 2019).

Jordan had a high population growth rate until recently. Jordan's population growth rate between 2000 and 2019 was within the range of 1.37% and 5.00%. However, 1.00% is the current population growth rate (World Population Review, 2020).

Van Afferden et al. (2010) epitomize in their study the wastewater situation in Jordan in several fundamental points as follows:

- The yearly available water consumption in Jordan is less than (200 m³/capita), one of the lowest worldwide.

- Some studies estimated daily water consumption between 77L to 83L/capita in the Jordanian northern urban areas. Where for the rural areas, it was between 20L to 28L/capita.

- Approximately 0.52 million people living in Jordanian rural areas principally depend on cesspools or planted ditches to discharge their wastewater as they do not have sewer systems or are not connected to central wastewater treatment systems. Mostly improperly sealed cesspools infiltrate through fractured rock and cause considerable groundwater pollution. Furthermore, some sewage tankers which suck those cesspools dump wastewater illegally into valleys. As a result, the robust need to establish decentralized wastewater treatment systems and reuse treated wastewater is essential.

- According to the Jordan National Water Master Plan, the planned amount of treated wastewater for reuse starting from 2020 has to be (101×10⁶m³/year). This quantity represents 15% of the available total renewable water resources.

- In the new water strategy (2009–2022) prepared by the “Royal Commission on Water”, the decentralized treatment systems should serve the semi-urban, rural communities, and even new urban settlements (Van Afferden et al., 2010).

Lienhoop et al. (2014) believe that Jordan has a lot of entirely unexploited water sources from the wastewater. 38% of the population (mostly in rural areas) is not connected to sewer systems, and accordingly, their wastewater does not treat in the centralized wastewater treatment plants for reuse purposes (Lienhoop et al., 2014). Attention to OWTs is a crucial issue that must be taken to protect the surface and groundwater besides protecting agricultural production in this country (Lienhoop et al., 2012; Lienhoop et al., 2014). Consequently, the reuse of the treated water is crucial to extenuating the physical, social, and economic stresses generated from this water scarcity (Van Afferden et al., 2015).

The on-site wastewater treatment Jordanian standards number 863/2006 approved by the Board of Directors of the Standards and Metrology Institution at its session No. 6/2006, held on 13/06/2006, is the Jordanian directive in use for on-site wastewater treatment systems evaluation.

The directive contains several sections that clarify general requirements, standard requirements, quality control, and evaluation mechanisms for reclaimed domestic wastewater. Table (1) summarizes the maximum standard values for the reclaimed water for discharge into torrents,

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valleys, or bodies of water and the maximum standard values for the reclaimed water reuse for irrigation.

Table (1): The standard values for both reclaimed water for discharge into torrents, valleys, or bodies and water reuse for irrigation.

Standards

Max. directive value for Reclaimed water for

discharge into torrents, valleys, or bodies of water

Reclaimed water reuse for irrigation

Biochemical oxygen demand (BOD5) 60 200

chemical oxygen demand (COD) 150 500

Dissolved oxygen (DO) > 1 -

Total suspended solids (TSS) 60 200

Power of hydrogen (pH) 6 - 9 6 - 9

Nitrate (NO3) 80 45

Total nitrogen (TN) 70 70

phosphorus (PO4) 15 30

Escherichia coli (E. coli) < 1000 < 1000

5-1. Jerash.

The two systems under assessment lie in the Sakib area in Jerash governorate, as can be seen in figure (1). Jerash governorate locates 53 km north of the Jordanian capital, Amman. The city lies at an altitude of 648 meters above sea level. According to the Köppen-Geiger system, Jerash's local climate is classified as Csa (Mediterranean hot summer climates) with occasional short and light freezing conditions in winters. Jerash has moderate to warm weather with an average temperature of 17.5 °C. The warmest month is August, with 25.2 °C. The coldest month is January, with 8.5 °C. Average annual precipitation is estimated at 393 mm, and more precipitation in the winter than the summer season. The driest month is June, with an average of 0 precipitations. The most rained month is January, with 92 mm precipitation (climate-data.org, ND).

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Figure 1. Location of study cases of wastewater treatment systems of septic tank followed by wetland wastewater (Sakib 1 and Sakib 2) in Sakib village – Jerash- Jordan

5-1-1. The vertical flow constructed wetland (VFCW) - Sakib 1.

This system was executed in July 2015 to treat the wastewater from a cluster consisting of five dwellings with an average flow rate of 290 L/day/house by a modified septic tank system. The modified septic tank system failed to comply with the designed targeted treatment purposes due to the lack of operational experience and shortage in the necessary maintenance. The septic tank system was upgraded lately to include a non-planted VFCW, which was put in service in January 2020. The upgraded system (modified septic tank and VFCW) currently serves a cluster of seven dwellings and thirty-six persons with an average flow rate of approximately 1.5 m³/day. The wastewater collects from each house to the built sewer chambers then directed to the septic tank (the modified septic tank previously). The septic tank was used as a pretreatment stage before pumping the wastewater to the wetland with a designed detention time of 3-4 days. The septic tank has a net inner dimension of 7.3 m length, 1.2 m width, and 1.20 m depth and divided into four chambers (three sedimentation chambers and a pumping chamber).

The wetland has a dimension of 10.0 m length, 4.0 m width, and 0.95 m depth. The wetland's walls were built with 20 cm concrete blocks and painted from outside by bituminous paint. From inside (for all walls and the wetland's base), covered and lined by a geotextile waterproofing membrane. The treatment media used was the zeolitic volcanic tuff and divided into three layers.

The top layer of the media (filter layer) was 65 cm and used an 8-16 mm gravel size, the second layer (transit layer) was 10 cm and used a 4-8 mm sand, and the base layer (drainage layer) used a 16-20 mm gravel size. The wastewater is fed to the wetland via a distribution network (perforated pipes) lies on the surface of the upper wetland's bed and covered with a shed, which is a halfpipe for aesthetic purposes. For aeration condition enhancement, two ventilators rise on the wetland surface where the first ventilator is connected to a 4-inch perforated pipe within the top layer and the other connected with the outlet drainage pipe in the bottom layer. The treated water flows from the wetland to the outlet concrete chamber. A submersible pump with an automatic float was placed in the feeding (pumping) chamber in the septic tank and based on the water height at the septic tank, the water to be pumped to the constructed wetland.

The effluent from the system currently discharges to the valley. However, the landlord where the constructed wetland was built is planning to store the treated water in a storage tank to be used

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soon to irrigate his farm. Figure (2) shows the different parts of the constructed wetland in Sakib 1, and figure (3) shows the schematic diagram for the septic tank followed by CW in Sakib 1.

(A) (B)

Figure (2): Illustration of wastewater treatment components in Sakib 1, which included the wetland (A), the septic tank (The modified septic tank previously) (B) .

Figure (3): The schematic diagram for the septic tank followed by CW in Sakib 1.

5-1-2. The recirculating vertical flow constructed wetland (RVFCW) - Sakib 2.

This system serves a cluster consisting of four dwellings and a total of twenty-four persons and an average flow rate of 1 m³/day. The recirculating constructed wetland's design parameters are based on EPA guidelines (1993). The wastewater is collected from each house to the built sewer chambers then directed to the septic tank. The septic tank was designed as a pretreatment to hold the wastewater with a designed detention time of 3-4 days, before pumping the wastewater to the wetland. The septic tank has a net inner dimension of 3.6 m length, 1.2 m width, and 1.6 m depth and divided into three chambers (two sedimentation chambers and dosing chamber). The wetland has dimensions of 7.5 m length, 5.5 m width, and 1 m depth. The wetland's walls were plastered and lined using polyethylene lining sheets with 6-8 µm diameters. The treatment media used was the zeolitic volcanic tuff and divided evenly to two layers 50 cm each. The top layer of the media (treatment layer) used a 4-8 mm gravel size, where the second layer (discharge layer) used a 16-20 mm gravel size. The wastewater feeds the wetland via a distribution manifold (perforated pipes) lies on the surface of the wetland's upper bed and covered with a shed, which is a halfpipe for aesthetic purposes. For nitrification and denitrification enhancement purposes, the

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treated water discharges from the wetland to a splitter chamber for recirculation. The splitter concrete chamber was built with a dimension of 1.40 × 0.6 × 0.35 m. The splitter was constructed to split the water from the constructed wetland into two volumes, i.e., 1/3 directed to the irrigation tank and 2/3 redirected to the septic tank. A submersible pump with an automatic float was placed in the septic tank and based on the water height at the septic tank, the water to be pumped to the constructed wetland.

The landlord of the land where the constructed wetland was built stores the treated water in a storage tank—the storage tank connected to an irrigation network extending over his farm's surface. Figure (4) shows the different parts of the constructed wetland in Sakib 2, and figure (5) shows the schematic diagram for the septic tank followed by recirculating constructed wetland in Sakib 2.

(A) (B)

(C) (D)

Figure (4): Illustration of wastewater treatment components in Sakib 2, which included the wetland (A), the septic tank (B) the splitter (C) and the storage tank (D).

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Figure (5): The schematic diagram for the septic tank followed by RCW in Sakib 2.

6. Methodology

6-1. Assessment of design parameters and actual loading conditions of the septic tanks and wetlands.

For assessing the design adequacy of the septic tanks and the wetlands, the actual operating parameters and loading conditions of the system were calculated. Specifically, actual People Equivalent (PE) of the systems, wastewater liquid volumes, hydraulic retention time (HRT), sludge volume, the required septic tanks volumes had been done.

The PE is the used term to describe the size of the wastewater treatment system. In practice, at average water consumption of (150 to 180) l/capita/day, it was assumed that this capita produces 54 grams of Biochemical oxygen demand (BOD) per 24 hours. The Actual People Equivalent (PE) was calculated according to equation (1).

Actual People Equivalent (PE) = BOD5 concentration × volume of wastewater / number of the people ………. Eq.(1)

The mean HRT was defined as the average time the wastewater stays inside the septic tank. HRT is a very crucial parameter for hydrogen and methane production within this time. The fermented hydrogen may shift to methanogenic one when HRT is prolonged (David et al., 2019). HRT was calculated according to equation (2).

Hydraulic retention time = volume of the tank / flow rate………. Eq.(2)

The sludge volume is the amount of the sludge accumulation per day in the tank and was calculated according to equation (3).

Sludge volume = sludge accumulation rate × number of people connected ………. Eq.(3) Where, the sludge accumulation rate is 0.234 l/capita/d (Gray, 1995).

The required septic tank volume for the system is the adequate volume for both daily wastewater liquid volume and the stored sludge until desludging. According to Franceys et al.

(1992), the required sludge storage capacity was calculated according to equation (4).

B = P × N × F × S………. Eq.(4) Where,

B = Required sludge storage capacity in liters.

P = Number of people connected to the tank.

N = Number of years between desludging.

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F = A factor which relates the sludge digestion rate to temperature and the desludging interval, (For N = 5 and Temperature between 10 – 20 ^oC, F = 1).

S = Rate of sludge accumulation that may be taken as 25 liters per person per year for tanks receiving WC waste only, and 40 liters per person per year for tanks receiving WC waste and sullage (Franceys et al.,1992).

For the wetlands, the hydraulic loading rate (HLR) and organic loading rate (OLR) had been calculated.

The HLR of the wetland is the volume of wastewater applied to one m² of the wetland per time.

The hydraulic loading rate was calculated according to equation (5).

Hydraulic loading rate = flow rate / area of wetland………. Eq.(5)

The OLR of the wetland is the amount of organic material per one m² of the wetland per time.

The Organic loading rate was calculated according to equation (6).

Organic loading rate = concentration of BOD5 × Hydraulic loading rate………. Eq.(6) 6-2. Treatment performance of the wetlands.

6-2-1. Wastewater sampling and analyses.

For evaluating the treatment performance of the wetlands, grab samples of wastewaters were collected at the wetland’s entry points and the wetland’s outlet. For Sakib 1, the inflow collection point to the wetland was located at the effluent of the septic tank (Figure 2b). For Sakib 2, the inflow to the wetland was located at the pumping compartment in the septic tank, and it included wastewater coming from the septic tank and recirculated effluent from the RVFW (Figure 4b).

Within two weeks, three samples were collected for Sakib 1 influent and effluent (Table 4). For Sakib 2, were two samples under the same period (Table 5). The inflow of the septic tank was not included in the sampling plan as the targeted treatment performance evaluation is for the wetlands. However, the results of previous measurements by RSS at the construction period were used for the wastewater BOD5 and TSS concentrations. The septic tanks will be evaluated regarding design parameters (volumes, sludge storage capacities, and hydraulic loading rates).

6-2-2. Laboratory tests and analysis.

For assessing the treatment performance of the two wetlands, several physical and chemical measurements and laboratory tests were conducted and analyzed for the wetlands' influents and effluents. The physical and chemical measures included pH, dissolved oxygen (DO), electric conductivity (EC), biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids (TSS), and nutrients values expressed by phosphorous (PO4-

), nitrate (NO3-

) and total nitrogen (N). Furthermore, some of the biological tests carried out to measure influents' and effluents' total coliform (TC), Escherichia coli (E.coli), and Pseudomonas Aeruginosa (P.

Aeruginosa).

The measured parameters were determined using chemical kits and according to methods shown in Table 2. The procedures for the determination of each of the test parameters were described in the manuals provided by the supplier and are briefly described in Appendix A.

The analytical quality was ensured by using control solutions with known concentrations of the substance for every measurement series (specified in Table 2).

HANI SHUBAIL

Assessment of on-site wastewater treatment systems in unsewered communities in Jordan

HANI SHUBAIL

Assessment of on-site wastewater treatment systems in unsewered communities in Jordan

Supervisor

Sahar Dalahmeh, PhD

Elzbieta Plaza, (Prof.)

Examiner

Elzbieta Plaza, (Prof.)

Hani Shubail Shubail@kth.se

Summary in Swedish

Abstract

Keywords

Acknowledgments

Table of contents

List of figures

List of tables

List of abbreviations and symbols

1. Introduction

2. Aim and objectives

3. Study borders and delimitations

4. Theoretical background

5. Study area

6. Methodology