Treatment and reuse of greywater for rye grass irrigation dissertation committee appointed by the scientific council of the discipline environmental engineering

POZNAŃ UNIVERSITY OF LIFE SCIENCES FACULTY OF ENVIRONMENTAL ENGINEERING AND SPATIAL MANAGEMENT MSc Eng Thanh Hung Nguyen TREATMENT AND REUSE OF GREYWATER FOR RYE-GRASS IRRIGATION (OCZYSZCZANIE I PONOWNE WYKORZYSTANIE ŚCIEKÓW SZARYCH DO NAWADNIANIA ŻYCICY TRWAŁEJ) Doctoral dissertation Supervisor: prof dr hab inż Ryszard Błażejewski Co-supervisor: dr hab Marcin Spychała Poznań 2019 TREATMENT AND REUSE OF GREYWATER FOR RYE-GRASS IRRIGATION (OCZYSZCZANIE I PONOWNE WYKORZYSTANIE ŚCIEKÓW SZARYCH DO NAWADNIANIA ŻYCICY TRWAŁEJ) Doctoral dissertation THANH HUNG NGUYEN Supervisor: prof dr hab inż Ryszard Błażejewski Faculty of Environmental Engineering and Spatial Management Co-supervisor: dr hab Marcin Spychała Faculty of Environmental Engineering and Spatial Management Dissertation Committee appointed by the Scientific Council of the Discipline: Environmental Engineering, Mining and Energy to be defended in public on Thursday 28 November 2019 at 11:00 a.m in Rada Wydzial room, Faculty of Environmental Engineering and Spatial Management Chairman: prof dr hab inż Jolanta Komisarek Faculty of Environmental Engineering and Spatial Management Reviewer: prof dr hab inż Janusz Łomotowski Wrocław University of Environmental and Life Sciences dr hab inż Joanna Jeż-Walkowiak Institute of Environmental Engineering Poznan University of Technology Acknowledgements I would like to extend my sincere thanks to my supervisor, Prof dr hab inż Ryszard Błażejewski, for his valuable support and supervision His advice, guidance, encouragement, and inspiration have been invaluable over the years Professor always keeps an open mind in every academic discussion I admire his critical eye for important research topics This dissertation would not have been completed without his guidance and support Additionally, I would like to thank dr hab Marcin Spychała, for supporting supervisor and his cooperative work He gave me valuable help whenever I asked for assistance I have learnt many useful things from him Further, I would like also to take this opportunity to thank the governments of Poland and Vietnam through Agreement between the Government of the Republic of Poland and the Government of Vietnam giving the opportunity to study in Poland and grant scholarships for my entire course The warmest thank to my colleagues at Department of Hydraulic and Sanitary Engineering, Poznań University of Life Sciences, for the stimulating discussions, supporting my works, and for providing the friendly environment in which we have learnt and grown during the past 4+ years Special thanks to Mrs Jolanta Zawadzka for her help in laboratory measurements Last but not least, I would like to thank my family and friends, for their constant love, encouragement, and limitless support throughout my life CONTENTS LIST OF FIGURES iv LIST OF TABLES .viii Abbreviation x ABSTRACT 1 INTRODUCTION 1.1 Background 1.2 Definitions of terms 1.3 Sustainable water resources management principles 1.4 Current and threatening water shortages 1.5 Importance of water reclamation and reuse 1.6 Justification for the study LITERATURE REVIEW 10 2.1 Composition of greywater 10 2.1.1 Quantity of greywater 10 2.1.2 Quality of greywater 12 2.1.3 Characterisation of greywater usability 13 2.2 Greywater treatment 15 2.3 Greywater reuse for irrigation 16 2.3.1 Standards and guidelines 16 2.3.2 Potential of greywater reuse for irrigation 19 2.3.3 Storage and diversion of greywater for reuse 21 2.3.4 Impacts of greywater reuse for irrigation 23 2.3.4.1 Human health 23 2.3.4.2 Soil 23 2.3.4.3 Groundwater 25 2.3.4.4 Yields 26 2.4 Economics of greywater reuse 27 2.5 Perennial ryegrass and its characteristics 29 2.6 Observed gaps in the literature 30 PURPOSE, SCOPE AND RESEARCH METHODS 31 i 3.1 Purpose and scope of the research 31 3.2 Hypotheses 31 3.3 Research methods 32 3.3.1 Material 35 3.3.2 Design of experimental with ryegrass 38 3.3.3 Research process 40 3.3.4 Experimental process on ryegrass 40 3.3.5 Collecting data and analysis 44 RESULTS OF THE STUDY 46 4.1 Study on greywater reuse for ryegrass irrigation without fertilizer supply 46 4.1.1 Balance of substances in all treatment combinations 46 4.1.2 Main and interaction effects among factors influencing the dry mass yield of ryegrass without fertilizer supply 49 4.1.2.1 Total dry mass of ryegrass after harvests without fertilizer supply 49 4.1.2.2 Total dry mass of ryegrass after harvest without fertilizer supply 57 4.1.3 Regression model for dry mass yield of ryegrass 64 4.1.4 Effect of irrigation water factors on soil pH 65 4.1.5 Effect of irrigation water factors on soil EC 70 4.1.6 Potential contaminant removal from greywater by planted ryegrass 75 4.2 Study on greywater reuse for ryegrass with fertilizer supply 79 4.2.1 Main and interaction effects among factors of irrigation water on dry mass yield of ryegrass with fertilizer supply 79 4.2.1.1 Total dry mass of ryegrass after harvests with fertilizer supply 79 4.2.1.2 Total dry mass of ryegrass after harvests with fertilizer supply 82 4.2.2 Effect of irrigation water factors on soil pH 87 4.2.3 Effect of irrigation water factors on soil EC 90 DISCUSSION 95 5.1 Effect factors on total dry mass yield of ryegrass 95 5.2 The leachate quality 97 ii 5.3 Effect factors on the change in soil pH and EC 98 5.4 Selecting factor settings for yield efficiency and reducing risk for planted soil irrigated with tap and greywater 100 CONCLUSIONS AND FUTURE RESEARCH 112 6.1 Conclusions 112 6.2 Future research 113 References 114 iii LIST OF FIGURES Figure 1.1 Overview of greywater terms Figure 2.1 Choosing methods for greywater treatment to reuse 16 Figure 3.1 Photo of experimental ryegrass in laboratory 33 Figure 3.2 The process of conducting the research 34 Figure 3.3 Compositions of raw and treated greywater used for irrigation 35 Figure 3.4 The lab-scale stand for greywater treatment 36 Figure 3.5 Particle size distribution of planted soil (sand) 37 Figure 3.6 The pot for experiment 37 Figure 3.7 Scheme of investigation with three factors (A, B, C) 38 Figure 3.8 The whole process of the study 40 Figure 3.9 Flowchart describing the entire experimental process on ryegrass 41 Figure 3.10 Schedule of experiment: (a) without fertilizer supply (Stage II); (b) with fertilizer supply (Stage III) 43 Figure 3.11 Flowchart for analysis from experimental design of the study 45 Figure 4.1 Balance of COD mass on all treatment combinations from irrigation water (Total mass matter = Uptake + Outlet) 46 Figure 4.2 Balance of total nitrogen mass on all treatment combinations from irrigation water 47 Figure 4.3 Balance of total phosphorus mass on all treatment combinations from irrigation water 48 Figure 4.4 Total dry mass yields of ryegrass after harvests of all treatment combinations without fertilizer supply 50 Figure 4.5 Effect of the main factors on the total dry mass yield of ryegrass after harvests without fertilizer supply 52 Figure 4.6 Two-way interaction of two factors affecting the total dry mass yield of ryegrass after harvests (83 days) without fertilizer supply 53 iv Figure 4.7 The two-way interaction effects of the factors in the low and the high level of another factor after harvests without fertilizer supply 54 Figure 4.8 Response surface as a function: (a) of tap water and treated greywater (at raw greywater mm/week); (b) of tap water and treated greywater (at raw greywater 15 mm/week); (c) of tap water and raw greywater (at treated greywater mm/week); (d) of tap water and raw greywater (at treated greywater 15 mm/week); (e) of treated greywater and raw greywater (at tap water mm/week); (f) of treated greywater and raw greywater (at tap water 15 mm/week) 56 Figure 4.9 Total dry mass yield of ryegrass after harvests for all treatment combinations without fertilizer supply 57 Figure 4.10 Effect of the main factors on the total dry mass yield of ryegrass after harvests (179 days) without fertilizer supply 60 Figure 4.11 Two-way interaction of two factors on the effects of the total dry mass yield of ryegrass after harvests (179 days) without fertilizer supply 60 Figure 4.12 The two-way interaction effects of the factors in the low and the high level of another factor after harvests without fertilizer supply 61 Figure 4.13 Response surface of total dry mass yield of ryegrass as a function: (a) of tap water and treated greywater (at raw greywater mm/week); (b) of tap water and treated greywater (at raw greywater 15 mm/week); (c) of tap water and raw greywater (at treated greywater mm/week); (d) of tap water and raw greywater (at treated greywater 15 mm/week); (e) of treated greywater and raw greywater (at tap water mm/week); (f) of treated greywater and raw greywater (at tap water 15 mm/week) 63 Figure 4.14 Correlation between irrigation water and total dry mass yield of ryegrass 64 Figure 4.15 pH of soil before initial and after experiment for all treatment combinations without fertilizer supply 66 Figure 4.16 Effect of main factors on soil pH without fertilizer supply 68 Figure 4.17 The two-way interaction of two factors on effect of the change in soil pH after finishing experiment (179 days) without fertilizers‘ supply 69 v Figure 4.18 Two-way interaction for all combinations of levels for the two factors on effect of the change in the soil pH after finishing experiment without fertilizer supply 70 Figure 4.19 Soil EC of all treatment combinations before initial and after conducted experiment 71 Figure 4.20 Effect of main factors on the change in soil EC 73 Figure 4.21 The two-way interaction of two factors influencing soil EC after finishing experiment (179 days) without fertilizer supply 73 Figure 4.22 Two-way interaction for all combinations of levels for the two factors on change in the soil EC after finishing experiment 74 Figure 4.23 The average pH of irrigation water and leachate of all treatment combinations during experiment 75 Figure 4.24 The average EC of irrigation water and leachate of all treatment combinations during experiment 76 Figure 4.25 COD of leachate from all treatment combinations for mean COD influent of raw greywater and treated greywater were 320 and 120 mg dm-3, respectively 77 Figure 4.26 Total nitrogen concentration of leachate from all treatment combinations 78 Figure 4.27 Total phosphorus concentrations of leachate from all treatment combinations 78 Figure 4.28 Total dry mass yield of ryegrass after harvests of all treatment combinations with fertilizer supply 80 Figure 4.29 Main factors affect on the total dry mass yield of ryegrass after three harvest times with fertilizer supply 81 Figure 4.30 The two-way interaction of two factors on the total dry mass yield of ryegrass after three harvest times with fertilizer supply 82 Figure 4.31 Total dry mass yield of ryegrass after six harvests for all treatment combinations 83 vi Figure 4.32 Main factors affect on the total dry mass yield of ryegrass after six harvests with fertilizer supply 85 Figure 4.33 The two-way interaction of two factors on the total dry mass yield of ryegrass after six harvests with fertilizer supply 86 Figure 4.34 Two-way interaction for all combinations of levels for the two factors on the total dry mass yield of ryegrass with fertilizer supply 86 Figure 4.35 Soil pH for all treatment combinations after experiment with fertilizer supply 87 Figure 4.36 Two-way interaction of two factors on the change in soil pH after six harvests with fertilizer supply 89 Figure 4.37 Two-way interaction for all combinations of levels for two factors soil pH with fertilizer supply 89 Figure 4.38 Soil EC for all treatment combinations before and after finishing experiment with fertilizer supply 90 Figure 4.39 Main effects of factors influencing soil EC 92 Figure 4.40 Two-way interaction of two factors influencing soil EC after six harvests with fertilizer supply 93 Figure 4.41 Two-way interaction impact for all combinations of levels for two factors on change in the soil EC with fertilizer supply 94 vii that using tap water and raw greywater during 83 days (3 harvests) as three separate categories of irrigation water without fertilizer supply (T.C9, 10, 11) However, after 183 days with harvests the yield was not significantly different from pots irrigated with raw greywater and treated greywater, only the pots irrigated with tap water gave significantly lower yield When ryegrass was supplied with fertilizer sufficiency, there were not significantly different total cumulative yields after 83 days and 179 days in respect to the three separate categories of irrigation water Many studies were conducted to compare effect of different types of irrigation water (tap water, treated greywater, raw greywater) Some studies concluded that biomass of plant irrigated with tap water was higher than when irrigated with treated greywater, however, there were also other conclusive studies (Mzini and Winter 2015) The resulting study of Alfiya (2012) supposed that treated greywater provided significantly higher than yield of ryegrass comparing to tap water and raw greywater, when irrigated with treated greywater from effluent of rotating biological contactor (RBC) and supplied with fertilizer after 111 days with harvests (Alfiya et al., 2012) On the contrary Pinto (2010) concluded that raw greywater was not significant in respect to biomass of silver beet (Pinto et al 2010) comparing to tap water irrigation or diluted 50% raw greywater with 50% tap water Moreover, the study reported that greywater reuse for grass irrigation in landscape gave higher than 160% biomass comparing to that irrigated by tap water (Laaffat et al., 2019) Garland (2000) supported the claim that surfactant in the raw greywater has inhibitory potential in the rhizosphere which may damage health of plants (Garland et al 2000) 5.2 The leachate quality Leachate from pots was collected to determine pH and EC (n = 27 samples) during the second stage of samples for experiment COD, total nitrogen, phosphorus were analyzed on the day of 28, 51, 100, 134 after start of the irrigation regime of experiment T.C1 did not produce any leachate pH and EC were calculated as the averages in irrigation water and leachate based on all collecting samples 97 Average pH of leachate was higher than that of irrigation water in all pots; pH of irrigation water fluctuated from 8.3 to 8.6 for all treatment combinations in the stage II Some authors suggested that pH of irrigation greywater should be lower than because it causes loss macronutrient during the plant growth (Christova-Boal et al., 1996, Siggins et al., 2016) Average pH of leachate fluctuated around that means it was slightly higher (from 0.4 to 0.7) as compared to irrigation water This result is similar to those of the study by Misra and Sivongxay (2009), Mohamed (2011), or Alfiya (2012) Average EC of irrigation water in all treatment combination ranged from 953 to 1059 S/cm According ANZECC and ARMCANZ (2000), EC of irrigation water can be accepted range from 650 to 1300 S/cm All average EC of leachate were higher than those of irrigation water EC of leachate in pots with low water depth was higher than in pots with higher water depth, although EC of irrigation water was not high difference among all treatment combinations The relevant study showed the EC increase from 959 S/cm (inflow) to 2638 S/cm (leachate) in experiment on grass planted in sand without any fertilizers (Mohamed 2011) 5.3 Effect factors on the change in soil pH and EC Soil pH and EC increased after finishing experiment both without fertilizer supply and with fertilizer supply of comparing with the initial soil pH of experiments, except for soil pH in T.C9 without fertilizer supply Sand-soil has low buffering capacity, so soil pH is easily changed by organic from irrigation water (Siggins et al., 2016) Soil EC is increased by greywater irrigation that means the soil is less able to support plant growth due to salinity and sodicity (Rodda et al., 2011) The result of increasing soil pH and EC, reported by Pinto and Maheshwari (2010) was explained by increased soil alkalinity and accumulated salts by detergents in greywater Moreover, Sawadogo (2014) explained that nutrients supply to soil is provided from irrigation water containing detergents Soil pH after finishing experiment without fertilizer supply among treatment combinations of full factorial experiment were not significantly different, however, they were higher than soil pH in the initial and in soil irrigated only tap water This result is consistent with the explanations in previous studies (Sawadogo et al., 2014, Travis et al., 2010) Moreover, Mzini and Winter (2015) reported that sandy 98 loam soil, irrigated with freshwater for a year, did not significantly change the initial soil pH The results show that tap water in the combined irrigation water was a effect factor decreasing soil pH when increasing its level, while treated greywater and interaction between treated greywater and tap water were the increasing factors They have significant effects on the change in soil pH In the combined effect of main effects, treated greywater is the most important factor, followed by tap water However, soil pH in all pots after finishing experiment with fertilizer supply was not significantly different from the initial value The only interaction between tap water and raw greywater has significantly had effect on the change in soil pH All main factors were not significant effect on the change in soil pH In addition, there were not significantly different soil pH value after finishing experiment among three controls irrigated by only tap water, treated greywater, raw greywater Soil EC after finishing experiment was significantly increased in T.C1 both without and with fertilizer supply That was effect of salt accumulation in the soil caused by irrigation without leachate in T.C1, and by raw greywater applied in T.C11 Soil EC has decreasing trend when increasing irrigation water depth Tap water was the most important factor in combined irrigation water without fertilizer supply during 179 days of experiment, the most next important factor was treated greywater, and raw greywater was the least main factor affected the soil EC However, all main factors and their interaction have significant effect on soil EC Soil EC in treatment combinations after finishing experiment were higher than the initial soil EC and fluctuated from 75 to 150 µS/cm, excepting T.C1 in which EC was higher than 250 µS/cm due to no leachate from these pots This result fits to that reported by Alley (2009) that the soil EC is not only depending on irrigation water, organic matter level, subsoil characteristics, salinity but also on soil texture and drainage condition Moreover, irrigation strategy or a ratio of combined dose components have potential to reduce the risk of salinity in soil (Pinto et al., 2010) Indeed, the combined irrigation water with fertilizer supply during cultivation of ryegrass in pots has shown that although the tap water was still the most important factor on the change in soil EC, the next important was the treated greywater However, the amplitude of magnitudes among main factors influencing the soil EC was relatively narrow 99 Therefore, hypothesis H4 regarding soil pH should be fully accepted in experiments with fertilizer supply and partly rejected in experiment without fertilizer supply the exceptions are T.C2 and T.C6 due to high share of tap water Hypothesis H4 regarding to soil EC should be fully rejected for experiment without fertilizer supply, and for experiment with fertilizer supply four combinations has confirmed H4 and four combinations did not 5.4 Selecting factor settings for yield efficiency and reducing risk for planted soil irrigated with tap and greywater The yield efficiency and the change in soil EC and pH irrigated tap water, treated and raw greywater are described in table 5.1 From table 5.1 one can choose an optimal irrigation strategy For example to achieved the maximum yield it would be recommended T.C3 of water depth 25 mm/week (5/ 15/ mm/week of tap water/ treated/ raw greywater) with fertilizer supply 100 Table 5.1 Matrix for selecting factor settings for yield efficiency for ryegrass and reducing risk of planted soil (for only main factors) Factor for combination Harvesting after 83 days Stage II Objective Maximum average yield Minimum average yield Minimum soil pH in the range 6