Water treatment residual: potential amendment to a sandy soil
| dc.contributor.advisor | Clarke, Catherine E. | en_ZA |
| dc.contributor.advisor | Hardie-Pieters, Ailsa G. | en_ZA |
| dc.contributor.advisor | Stone, Wendy | en_ZA |
| dc.contributor.author | Steytler, Jan George | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of AgriSciences. Dept. of Soil Science. | en_ZA |
| dc.date.accessioned | 2021-02-26T14:02:47Z | |
| dc.date.accessioned | 2021-04-21T14:39:16Z | |
| dc.date.available | 2021-02-26T14:02:47Z | |
| dc.date.available | 2021-04-21T14:39:16Z | |
| dc.date.issued | 2021-03 | |
| dc.description | Thesis (MScAgric)--Stellenbosch University, 2021. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: Water treatment residual (WTR) is a waste product generated during the water treatment process. This study assesses the potential of using WTR as a potential amendment or co- amendment with commercial compost, to the sandy soils common in the Cape Town metropolitan area. The study set out to: i) characterise the Alum-WTR collected in 2019 and Ferric-WTR collected in 2018 and 2019, a sandy topsoil and compost through mineralogical and chemical characterization, ii) determine the soil-water interactions of Ferric-WTR (2018) single amendment and co-amendment with compost at application rates of 10% w/w (225 tons/ha) and 20% w/w (450 tons/ha), iii) conduct a greenhouse experiment on Swiss Chard (Beta vulgaris cicla.) growth in a sandy topsoil with 10% and 20% single amendments of compost and Ferric-WTR (2018) and a WTR-compost co-application (20%) under water and nutrient- induced stress, and iv) investigate the effect of the Ferric-WTR (2018) amended sandy topsoil on trace element plant availability and phytotoxicity. The properties of the Alum-WTR (2019), Ferric-WTR (2018 and 2019) samples was characterised in terms of morphology, mineralogy, specific surface area, EC, pH, aqua regia extractable elements, exchangeable cations and acidity and ammonium oxalate extractable Al, Mn and Fe. The adsorption of phosphate to the WTR was fitted to Langmuir and Freundlich isotherm models. The analysed WTRs exhibit irregular surface morphology and a large specific surface area (84.80 – 144.13 m²/g). The X-ray diffraction results showed that the crystalline phases from the raw water are quartz, muscovite, kaolinite and feldspar, while the Al and Fe derived from the treatment process is mainly held in poorly crystalline phases. The WTR from both water treatment plants (WTP) contained Al, Fe, Cr, Mn, Co, Ni, Cu, Zn, As, and Pb. The EC of the WTRs ranged between 0.24 -0.8 dS/m while the pH (KCl) ranged from 4.7 to 6.6 and the CEC of Ferric-WTR (2018) was the highest at 90 cmolc/kg, followed by 25 cmolc/kg for the Ferric WTR (2019) and 6 cmolc/kg for Alum-WTR (2019). The maximum P sorption was 12.62 mg/g and 12.01 mg/g for Ferric-WTR (2019) and Alum-WTR (2019), respectively. The soil water repellency (SWR) of the Ferric-WTR (2018), compost and WTR-compost co- application was investigated trough a Water Drop Penetration Time test (WDPT). The water retention characteristics of the amendment mixtures were determined with pressure plates. The SWR of the sandy topsoil was significantly reduced from 1661 seconds to 67 seconds by the 20% Ferric-WTR (2018) amendment. The Ferric-WTR (2018) amendment mixtures (10% and 20%) resulted in an upward shift in the water retention curve, without altering the retention curve shape. The 20% Ferric-WTR (2018) amendment resulted in a 12.5% increase in the total available-water holding capacity (TAWC). The increased water content at all matric potentials is related to water held in the micropores of the WTR. A 6 x 2 x 2 factorial ANOVA (6 amendment mixtures, 2 water levels and 2 fertiliser levels) on the water use efficiency (WUE) of Swiss Chard was conducted. The unfertilized treatment combinations were analysed colourimetrically for plant available P and N with a Mehlich-3 extract and a 2 M KCl solution and ammonium and nitrate test kits. The factorial ANOVA on WUE resulted in significant interaction. The treatment combinations were subsequently analysed by a single factor ANOVA. The WUE of the unfertilised water-unstressed WTR- compost co-application resulted in a 16-fold increase in WUE relative to the control. The WTR addition to the sandy soil reduced the plant availability of P. The WTR-compost co-application improves Swiss Chard biomass production and WUE under water and nutrient-limited conditions, and it outperformed both the control and the WTR single amendment. The plant-available trace elements of the unfertilized amendment mixtures was extracted in a Mehlich-3 extract. Both the unfertilised 20% Ferric-WTR (2018) single amendment and the WTR-compost co-amendment, WTR reduced the plant availability of As, Pb, Mo, Cu and Zn, while the Ferric-WTR is a source of Al, Cr, Mn, Fe, Co and Ni in comparison to the sandy topsoil. No treatment combination resulted in Pb, Ni, Mn, Cu and Zn exceeding the Mehlich-3 toxicity threshold. Land application of a WTR-compost co-application to a poor sandy soil is a viable conduit for diverting waste from landfill into agricultural potential. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Waterbehandelingsresidu (WTR) is 'n afvalproduk wat tydens die waterbehandelingsproses gegenereer word. Hierdie studie ondersoek die potensiaal van WTR as 'n moontlike aanvulling of mede-aanvulling te same met kommersieel beskikbare kompos tot die sanderige grond, algemeen in die groter metropool van Kaapstad. Die studie het ten doel gehad: i) om die Alum-WTR wat in 2019 versamel is, en Ferric-WTR wat in 2018 en 2019 versamel is, 'n sanderige bogrond en kompos deur fisiese en chemiese karakterisering te ontleed, ii) die grond-water-wisselwerking van Ferric-WTR (2018) as enkel aanvulling en mede-anvulling met kompos teen toedieningshoeveelhede van 10% w/w (225 ton/ha) en 20% w/w (450 ton/ha) te bepaal, iii) 'n kweekhuiseksperiment wat die groei van Swiss Chard (Beta vulgaris cicla.) in 'n sanderige bogrond met 10% en 20% enkel aanvullings van kompos en Ferric-WTR (2018) asook 'n WTR-kompos mede- anvulling onder water en nutrient spanning te ondersoek, en iv) om die effek van die Ferric-WTR (2018) aanvulling tot `n sanderige bogrond op die beskikbaarheid spoorelementplante en plant toksisiteit te ondersoek. Die eienskappe van die Alum-WTR (2019), Ferric-WTR (2018 en 2019) monsters is ontleed in terme van morfologie, mineralogie, spesifieke oppervlakte, EC, pH, aqua regia- oplosbare elemente, uitruilbare katione en suurheid en ammoniumoksalaat oplosbare Al, Mn en Fe. Die adsorpsie van fosfaat aan die WTR is gepas op Langmuir en Freundlich isotermmodelle. Die analiese van die WTRs toon onreëlmatige oppervlakmorfologie en 'n groot spesifieke oppervlak (84,80 - 144,13 m²/g). Die resultate van die X-straal diffraksie toon dat die kristallyne fases, kwarts, muskoviet, kaoliniet en veldspaat is van die rou water, terwyl die Al en Fe wat van die behandelingsproses afkomstig is, hoofsaaklik in swak kristallyne fases gehou word. Die WTR van beide waterbehandelingsaanlegte (WTP) bevat Al, Fe, Cr, Mn, Co, Ni, Cu, Zn, As en Pb. Die EC van die WTR's het gewissel tussen 0,24 -0,8 dS/m, terwyl die pH (KCl) van 4,7 tot 6,6 wissel en die CEC van Ferric-WTR (2018) die hoogste was met 90 cmolc/kg, gevolg deur 25 cmolc/kg vir die Ferric WTR (2019) en 6 cmolc/kg vir Alum-WTR (2019). Die maksimum fosfaat sorpsie was onderskeidelik 12,62 mg/g en 12,01 mg/g vir Ferric-WTR (2019) en Alum- WTR (2019). Die water hidrophobisteit eienskappe (SWR) van die Ferric-WTR (2018), kompos en WTR- kompos mede- aanvulling is ondersoek deur 'n waterdruppel penetrasie-toets (WDPT). Die water retensie-eienskappe van die aanvulling kombenaies is met drukplate bepaal. Die SWR van die sanderige bogrond is aansienlik verminder van 1661 sekondes tot 67 sekondes deur die 20% Ferric-WTR (2018) aanvulling. Die Ferric-WTR (2018) aanvulling kombenasies (10% en 20%) het gelei tot 'n opwaartse skuif van die waterretensie-kurwe, sonder om die vorm van die retensie-kurwe te verander. Die Ferric-WTR (20%) aanvulling het gelei tot 'n toename van 12,5% in die totale beskikbare waterhouvermoë (TAWC). Die verhoogde waterinhoud by alle matriekspotensiale hou verband met water wat in die mikropore van die WTR gehou word. 'n 6 x 2 x 2 ANOVA (6 aanvulling kombenasies , 2 water tedienings en 2 kunsmis aanvullings) op die water gebruikseffektiwiteit (WUE) van Swiss Chard is uitgevoer. Die behandelings kombinasies sonder kompos toediening is geanaliseer vir plant beskikbaar P en N met 'n Mehlich-3 uittreksel en 'n 2 M KCl oplossing met ammonium en nitraat toetsstelle. Die faktoriale ANOVA op WUE het beduidende interaksie tot gevolg gehad. Die behandelingskombinasies is vervolgens deur 'n enkele faktor ANOVA geanaliseer. Die WUE van die kunsmis- en water-arm WTR-kompos-toediening het gelei tot 'n 16-voudige toename in WUE in vergelyking met die kontrole. Die toevoeging van WTR tot die sanderige grond het die beskikbaarheid van P verminder. Die WTR-kompos-toediening verbeter die produksie van Swiss Chard-biomassa en WUE onder water- en voedings beperkte toestande, en dit het beter gevaar as die enkele aanvulling van WTR en die kontrole. Die plantbeskikbare spoorelemente van die kunsmis arm aanvulling kombenasies is met 'n Mehlich-3-ekstrak onttrek. Beide die onbemeste 20% Ferric-WTR (2018) enkel aanvulling en die WTR-kompos mede- anvulling, het WTR die plantbeskikbaarheid van As, Pb, Mo, Cu en Zn verminder, terwyl die Ferric-WTR 'n bron is van Al, Cr, Mn, Fe, Co en Ni is in vergelyking met die sanderige bogrond. Geen behandelingskombinasie het daartoe gelei dat Pb, Ni, Mn, Cu en Zn die Mehlich-3 toksisiteitsdrempel oorskry het nie. Grondtoediening van 'n WTR-kompos mede-aanvulling, op 'n swak sanderige grond is 'n lewensvatbare alternatief tot stortingsterrein berging, en kan `n afvalproduk omskep in landboupotensiaal. | af_ZA |
| dc.description.version | Masters | en_ZA |
| dc.format.extent | xvi, 126 pages : illustrations, maps | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/110078 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Water treatment residual | en_ZA |
| dc.subject | Soil amendments | en_ZA |
| dc.subject | Sandy soils -- South Africa -- Western Cape | en_ZA |
| dc.subject | Compost | en_ZA |
| dc.subject | Waste product | en_ZA |
| dc.subject | UCTD | en_ZA |
| dc.title | Water treatment residual: potential amendment to a sandy soil | en_ZA |
| dc.type | Thesis | en_ZA |