Dairy Wastewater Research Articles

Reduced graphene oxide-nano zerovalent iron assisted anaerobic digestion of dairy wastewater: A potential strategy for CH4 enrichment

Efficient waste management and alternatives for waste reduction have been the prime factors in achieving sustainable development goals. Large quantities of waste biomass can be transformed to energy by anaerobic fermentation. This study focused on improving the electron transport and subsequent CH4 enrichment in the anaerobic digestion of dairy wastewater by adding reduced graphene oxide-nano zerovalent iron (RGO-NZVI) composite. Different ratios (wt/wt) of RGO and NZVI were added to the anaerobic digesters and monitored their effects on biogas volume, composition, COD removal and VFA accumulation. There was 86.27 ± 2.8% high CH4 and 47.37 ± 1.3% improved COD removal in the digester containing the conductive additive compared to control. Comparing different ratios of RGO-NZVI revealed that a proportion of 2:1 was beneficial for maximum CH4 generation. Further, it was found that higher concentrations of the conductive additives could be fatal for microbial metabolism. A ratio of 0.5:1 had minimal support on degradation and the composition of CH4 in this digester was 34.14 ± 1.5% less than control. The metagenomic analysis showed that the diversification of microbial community and switching of major mechanism to direct interspecies electron transfer caused higher CH4 generation.

Evaluation of Lemna minor phytoremediation performance for the treatment of dairy wastewater

Abstract The aim of the study was to evaluate the efficiency of Lemna minor to purify synthetic dairy wastewater (SDW) and real dairy wastewater (RDW), both diluted and undiluted. Results showed that Lemna significantly reduced electrical conductivity (EC); the removal efficiency for EC was 19.4% in RDW and 9.8% in SDW. Higher values were recorded for diluted real dairy wastewater (DRDW) (41%) and for diluted synthetic dairy wastewater (DSDW) (35.8%). Total suspended solids were slightly reduced in RDW (14%) and SDW (13.5%), compared to DSDW (25%) and DRDW (29%). Greater removing efficiency of chemical oxygen demand was recorded in DRDW (60%) and DSDW (55.5%) compared to RDW (27.6%) and SDW (27%). In RDW, nitrogen and phosphorus removal were 24.8 and 37.4% and in SDW were 25 and 48.6%, respectively, compared to much higher results in diluted effluents, and nitrogen removal was 65.4% in DRDW and 63.5% in DSDW, but the best results were recorded for phosphorus removal in DSDW (78.8%) and DRDW (87%). The higher elimination of all the parameters investigated in the units populated with duckweed compared to the control attests to the effectiveness of L. minor in the phytoremediation of dairy wastewater, especially when reducing the primary pollutant load.

Primary treatment with a natural coagulant improved the nanofiltration stage to recover dairy wastewater

AbstractBackgroundThe adequate management of dairy effluent is of prime importance to mitigate environmental damages. In addition, its adequate treatment could enable its reuse inside the dairy industry, contributing to a sustainable economy.ResultsThe optimization of the coagulation/ flocculation/ sedimentation stage through a Box–Behnken Design was proposed using real dairy effluent and natural coagulant of Moringa extracted with CaCl2. Then, nanofiltration with a NF 270 membrane was applied, using the raw wastewater and the wastewater pre‐treated with coagulation/ flocculation/ sedimentation, enabling apparent color and turbidity removals of >98% in the three studied conditions. A satisfactory chemical oxygen demand (COD) removal of 88.9% was obtained only with the combination of the pre‐treatment by coagulation/ flocculation/ sedimentation followed by nanofiltration. When the effluent was subjected to nanofiltration directly, the COD removal did not reach 61%. Besides improving the removal values, the pre‐treatment improved the transmembrane flow, reducing the fouling and the membrane total resistance when compared to the dairy wastewater directly subjected to nanofiltration.ConclusionWhen the wastewater was pre‐treated using the natural coagulant, the nanofiltration stage was improved because the membrane presented a lower fouling (~10%), lower total resistance and less calcium build‐up compared to direct nanofiltration of the wastewater (~60%). This indicates that the membrane lifespan can be extended when the pre‐treatment is applied. The quality evaluation of the treated effluent demonstrated that it presents the potential to be reused inside the dairy industry, which could greatly contribute to a sustainable and economic scenario. © 2023 Society of Chemical Industry (SCI).

Psychrophilic and mesophilic anaerobic treatment of synthetic dairy wastewater with long chain fatty acids: Process performances and microbial community dynamics

Facilitating the anaerobic degradation of long chain fatty acids (LCFA) is the key to unlock the energy potential of lipids-rich wastewater. In this study, the feasibility of psychrophilic anaerobic treatment of LCFA-containing dairy wastewater was assessed and compared to mesophilic anaerobic treatment. The results showed that psychrophilic treatment at 15 ℃ was feasible for LCFA-containing dairy wastewater, with high removal rates of soluble COD (>90%) and LCFA (∼100%). However, efficient long-term treatment required prior acclimation of the biomass to psychrophilic temperatures. The microbial community analysis revealed that putative syntrophic fatty acid bacteria and Methanocorpusculum played a crucial role in LCFA degradation during both mesophilic and psychrophilic treatments. Additionally, a fungal-bacterial biofilm was found to be important during the psychrophilic treatment. Overall, these findings demonstrate the potential of psychrophilic anaerobic treatment for industrial wastewaters and highlight the importance of understanding the microbial communities involved in the process.

Biogas Production and Metagenomic Analysis in a New Hybrid Anaerobic Labyrinth-Flow Bioreactor Treating Dairy Wastewater

Increasing worldwide milk manufacturing and dairy processing resulted in producing more effluents, and thus effective management of wastewater is now the most important issue. This study used a new design of a pilot plant-scale hybrid anaerobic labyrinth-flow bioreactor (AL-FB) to increase the efficiency of anaerobic biodegradation and biogas productivity and improve anaerobic microflora performance. In addition, effluent recirculation was used to boost the treatment of dairy wastewater. Metagenomic analyses of the anaerobic microbial community were performed. It was found that an organic loading rate (OLR) of 4.0–8.0 g COD/L·d contributed to the highest CH4 yield of 0.18 ± 0.01–0.23 ± 0.02 L CH4/g COD removed, which corresponded to a high COD removal of 87.5 ± 2.8–94.1 ± 1.3%. The evenest distribution of the microorganisms’ phyla determined the highest biogas production. In all tested samples, Bacteroidetes and Firmicutes abundance was the highest, and Archaea accounted for about 4%. Metagenomic studies showed that methane was mainly produced in acetoclastic methanogenesis; however, higher OLRs were more favorable for enhanced hydrogenotrophic methanogenesis. Effluent recirculation enhanced the overall treatment. Thus, at OLR of 10.0 g COD/L·d, the highest COD removal was 89.2 ± 0.4%, and methane production yield achieved 0.20 ± 0.01 L CH4/g COD removed, which was higher by 25% compared to the achievements without recirculation.

Investigation of Different Pre-Treatment Techniques and 3D Printed Turbulence Promoter to Mitigate Membrane Fouling in Dairy Wastewater Module.

This study investigates the enhancement of dairy wastewater treatment using chemical and physical pre-treatments coupled with membrane separation techniques to reduce membrane fouling. Two mathematical models, namely the Hermia and resistance-in-series module, were utilized to comprehend the mechanisms of ultrafiltration (UF) membrane fouling. The predominant fouling mechanism was identified by fitting experimental data into four models. The study calculated and compared permeate flux, membrane rejection, and membrane reversible and irreversible resistance values. The gas formation was also evaluated as a post-treatment. The results showed that the pre-treatments improved UF efficiency for flux, retention, and resistance values compared to the control. Chemical pre-treatment was identified as the most effective approach to improve filtration efficiency. Physical treatments after microfiltration (MF) and UF showed better fluxes, retention, and resistance results than ultrasonic pre-treatment followed by UF. The efficacy of a three-dimensionally printed (3DP) turbulence promoter was also examined to mitigate membrane fouling. The integration of the 3DP turbulence promoter enhanced hydrodynamic conditions and increased the shear rate on the membrane surface, shortening filtration time and increasing permeate flux values. This study provides valuable insights into optimizing dairy wastewater treatment and membrane separation techniques, which can have significant implications for sustainable water resource management. The present outcomes clearly recommend the application of hybrid pre-, main- and post-treatments coupled with module-integrated turbulence promoters in dairy wastewater ultrafiltration membrane modules to increase membrane separation efficiencies.

Effect of Organic Loading Rates on Performance of Treating Dairy Wastewater in a Lab-Scale Sequencing Batch Reactor

This study aims to investigate, the effect of organic loading rates (OLRs), nutrient ratio addition, and sludge retention time (SRT) on treating dairy wastewater in a sequencing batch reactor (SBR) system. This investigation is verified by experiments conducted in 3 phases at 3 different OLRs (1.8, 1.2, and 0.9 kg/m3d, respectively). Urea ((NH2)2CO) is added to make a suitable (COD:N:P) ratio of (100:5:1) in dairy wastewater. The SRT is adjusted from 50 days to an appropriate value of 18 days. The obtained results show that the COD, TN, and TP removal efficiencies are increased with decreasing OLRs. Sludge concentration in the SBR tank is stable at 1100 mg/L after adding (NH2)2CO. In addition, the SBR operated at a suitable SRT (i.e. 18 days) helps the biomass stably, resulting in enhancement of COD, TN, and TP removal. The results are helpful to the design of SBR for treating dairy wastewater.

Voltammetric method for chemical oxygen demand in a dairy wastewater using homemade minimal instrumentation

This paper presents a voltammetric method for Chemical Oxygen Demand (COD) quantification in a dairy wastewater using homemade minimal electrochemical instrumentation. The working electrode was a carbon microdisc, the auxiliary electrode was a carbon rod, and a silver electrode was used as reference. A low-cost non-commercial potentiostat was employed. The linear working range was 1-20 g/L. Repeatability was evaluated on 10 sample quantifications, the coefficient of variation was 3.6%, lower than that obtained for the reference spectrophotometric method (8.2%). The voltammetric method did not require treatment of the sample. The trueness was evaluated by comparing the voltammetric results with the spectrophotometric method. Mean COD of 10 quantifications using low-cost voltammetry was 10.2 g/L, whereas for the spectrophotometric method it was 11.0 g/L. A Paired Sample t-Test did not show statistically significant differences between both. Detection limit was 0.6 g/L, and quantification limit was 1.8 g/L. Both are acceptable for the sample in which there is a high organic content.

Effective production of bacterial cellulose using acidic dairy industry by-products and agro wastes

The study aimed to evaluate the production of bacterial cellulose (BC) by specialized bacteria using raw acidic dairy wastewater and milk whey as well as evaluating the bioremediation ability of the tested bacteria for the purification of polluted wastewater. Raw dairy wastewater samples were collected from Milk Factory in Alexandria Governorate, Egypt. Three bacterial isolates were isolated from spoiled Tomato (T0) and Pomegranate (R01 &R02), and investigated as free-living and fixed individual and mixed cultures in batch mode bioassays. BC was extracted, determined and characterized. T0, R01 &R02 were molecularly identified as Bacillus velezensis strain FZB42 (T0), Klebsiella quasipneumoniae subsp. similipneumoniae strain 07A044 (R01 and R02). T0 achieved the maximum BC yield of 31.9 g/L compared to 13.18 g/L produced by the standard synthetic Hestrin-Schramm (HS) medium. It also showed the highest growth stimulation (7.78-fold higher density than its initial density). All strains showed the highest removals of the TSS, TDS, COD and BOD reaching residual concentrations (RCs) of 12, 2050, 75 and 25 mg/L, respectively, all of which were much lower levels than their limits stated by environmental laws (60, 5000, 80 and 60 mg/L, respectively). BC production by the tested bacteria grown in the raw dairy wastewater is considered an excellent achievement, feasible and value-added technology. The tested bacteria are remarkably efficient for the treatment of dairy effluents in a very short time. Therefore, it is highly recommended to use the proposed bacterial system for feasible BC production and purification of highly polluted dairy wastewater.

Комплексная биологическая очистка сточных вод предприятий мясо-молочной промышленности

About 200 enterprises producing meat product and more than 50 enterprises of the dairy industry operate in the Republic of Belarus. Up to 70 % of the water used in these industries is contaminated with fatty substances. At present, physicochemical methods (coagulation and flocculation) and biological treatment using microorganisms-destructors of fats and oils are most widely used for the treatment of fat-containing wastewater, it is advisable to use these treatment methods in combination. Recently, more and more attention has been paid to the complete or partial replacement of chemical flocculants by biological or microorganisms with flocculating ability. In this paper, the process of wastewater treatment of meat and dairy industry enterprises was studied using a consortium of flocculant microorganisms and the microbial preparation Antoil. The investigated microbial consortium was shown to be as active as the most common polyacrylamide-based synthetic flocculants used for wastewater treatment. The flocculating activity was 92-98 %. It has been established that the process of purification of the studied wastewater with the help pf the consortium of microorganisms used depends on the temperature and pH value of the effluents. Dairy and meat industry wastewater was treated with an efficiency of 60.9-98.0 % in 7 days in the temperature range of 10-40 °C and pH 4-9. It is shown that the use of a consortium of flocculant microorganisms makes it possible to achieve high rates of wastewater treatment of a cheese-making plant and a poultry farm not only in terms of suspended solids, but also in terms of COD. The effectiveness of the combined use of a consortium of flocculant microorganisms and the microbial preparation Antoil for the treatment of wastewater from poultry farms and maintaining the treatment efficiency at a high level (86.5-92.9 %) during burst discharges has been practically confirmed.

Evaluating the potential of a new reactor configuration to enhance simultaneous organic matter and nitrogen removal in dairy wastewater treatment

The dairy industry is a very productive sector worldwide and known for producing great volumes of wastewater that is rich in organic matter and nutrients. Apart from fat, the organic matter in such effluents is easily degradable, demanding an external carbon source for conventional denitrification. In this manner, new configurations of reactors promoting a suitable environment for more sustainable nitrogen removal are beyond required-they are paramount. Therefore, the performance of a structured-bed hybrid baffled reactor (SBHBR) with anaerobic and oxic/anoxic chambers was designed and assessed for treating different dairy wastewaters. A combination of baffled and biofilm-structured systems under intermittent aeration was the solution proposed to obtain a new method for nitrogen removal under low COD/TN ratios. The COD/TN ratios tested were 2.1 ± 0.6, 0.84 ± 0.5, and 0.35 ± 0.1 in the inlet of the O/A chambers for operational stages I, II, and III, respectively. The SBHBR provided COD removal efficiencies above 90% in all experimental stages. During stage III, the process had nitrification and denitrification efficiencies of 85.9 ± 17% and 85.2 ± 9%, respectively, resulting in a TN removal efficiency of 74.6 ± 14.7%. Stoichiometric calculations were used to corroborate the activity of bacteria that could perform the anammox pathways as their main mechanisms.

Advanced treatment of toluene emissions with a cutting-edge algal bacterial photo-bioreactor: Performance assessment in a circular economy perspective

A novel approach for the treatment of VOCs (by using toluene used as a model compound) and the simultaneous conversion of carbon dioxide into valuable biomass has been investigated by using a combination of an activated sludge moving bed bioreactor (MBBR) and an algal photo-bioreactor (PBR).The first unit (MBBR, R1) promoted toluene removal up to 99.9 % for inlet load (IL) of 119.91 g m−3 d−1. The CO2 resulting from the degradation of toluene was then fixed in PBR (R2), with a fixation rate up to 95.8 %. The CO2 uptake was promoted by algae, with average production of algal biomass in Stage VI of 1.3 g L−1 d−1. In the contest of the circular economy, alternative sources of nutrients have been assessed, using synthetic urban wastewater (UWW) and dairy wastewater (DWW) for liquid renewal. The produced biomass with DWW showed a high lipid content, with a maximum productivity of 450.25 mg of lipids L−1 d−1. The solution proposed may be thus regarded as a sustainable and profitable strategy for VOCs treatment in a circular economy perspective.

Microalgae: Nature’s Green System to Recycle Waste to Resource

Dairy wastewater management is a major concern for many milk-producing countries as it is a serious nuisance to the surroundings when disposed of untreated, increasing the organic load and foul smell. Microalgae remediation is an easy and cost-effective treatment to treat the effluent and simultaneously enhance a few agronomic traits. In this research, the phytoremediation technique was validated by treating dairy effluent using microalgal consortium and to study its impact on seed germination assay of Vigna mungo (Black gram). The results exhibited a significant increase in germination index, vigor index, and germination percentage when undiluted effluent was treated with microalgal consortium followed by other dilutions. Seedling growth was found maximum in 100% microalgal treated (TE100) undiluted effluent followed by 75% dilution (TE75), 50% dilution (TE50), 25% dilution (TE25), (TE0) treated effluent and compared with controls: water, effluent, fertilizer. So, we conclude that dairy effluent treated with suitable microalgae can be used directly for irrigation purposes to produce plants with high yield and significant biomass, indirectly making the industry a place of zero-waste discharge.

Recovery of cleaning agents from Clean-In-Place (CIP) wastewater using nanofiltration (NF) and direct contact membrane distillation (DCMD)

Increasing concerns about freshwater sources necessitate the management of wastewater, such as the wastewater generated from Clean-in-Place (CIP) operations. In this investigation, a membrane system composed of nanofiltration (NF) and direct contact membrane distillation (DCMD) was proposed to manage model dairy CIP wastewater that contained NaOH as an alkaline cleaning agent. During the NF step, prefiltration by a 4 kDa membrane or a 4 kDa membrane followed by a 200 Da membrane (4 kDa/200 Da) was used to remove the whey protein and lactose. With these two membranes in series of NF, the protein concentration was reduced by 92.4% and the lactose content was reduced to a non-detectable level when compared to the model CIP wastewater. Before concentrating the permeates from NF steps, three DCMD membranes (FR, Solupor, and ST) with different characteristics were evaluated to manage the NF permeates from 4 kDa or 200 Da NF. An increase in the feed temperature from 40 °C to 60 °C resulted in an increase in the water flux during DCMD operation, except for FR. In addition, it was found that ST generated the highest water flux when compared to the other membranes. Using ST and a feed temperature of 60 °C, the permeates from 4 kDa or 4 kDa/200 Da were continuously concentrated for 7 h with DCMD. During this concentration, there was no significant decline in flux. The cleaning effectiveness of the cleaning agent (NaOH) recovered by NF and DCMD was compared with a fresh cleaning solution using quartz crystal microbalance with dissipation (QCM-D). It was found that the cleaning agents recovered by 4 kDa/200 Da NF presented a statistically identical cleaning rate compared to fresh NaOH. This research highlights the potential of NF and DCMD to regenerate alkaline cleaning agents, while reclaiming water from dairy CIP wastewater.

Bioenergy production from bacteria (Methanogens)

The research deals with anaerobic fermentation and creating the conditions for bacteria (Methanogens) to carry out the process of hydration, acidification and production of methane gas. The study included the design of an anaerobic reactor made of thick glass (12) mm, with dimensions (of 35 x 35 x 35) cm, with a thermal heater inside it and a temperature set at (45) ℃, and then filled with Dairy wastewater. The Treatment period of the reactor reached two months, during which water samples were taken (72hrc) for laboratory tests (pH, COD). The laboratory tests began on 1/1/2021 and ended on 1/3/2021. COD removal of 87.12% was achieved with a neutral pH at the beginning of the second month of treatment. Biogas was obtained in this anaerobic reactor by fermentation and in the presence of bacteria (Methanogens), and its amount during the treatment period was 1.6 m3. Keywords: Bioenergy, Dairy waste Water, anaerobic reactor, Fermentation, bacteria (Methanogens)

Recovery of cleaning agents from clean-in-place (CIP) wastewater using nanofiltration (NF) and forward osmosis (FO)

This study proposed a Nanofiltration (NF) – Forward Osmosis (FO) membrane system to recover the cleaning agents from model dairy CIP wastewater. The NF steps consist of 4 kDa and 200 Da Nanofiltration (NF) membrane to reduce the lactose and whey protein before the forward osmosis (FO) concentration step. It was found that a series of NF filtration (4 kDa-200 Da) eliminated the lactose under detection level and protein by 96.3 %. The permeates from 4 kDa or 200 Da NF were further treated with FO. Two different FO membranes, cellulose triacetate (CTA) and thin-film composite (TFC). The increase of salts concentration from 0.5 M to 2.0 M increased the water flux from 17.8 LHM to 31.7 LHM when the TFC membrane was used. 4 times increase in the salts concentration did not result in the same magnitude increase in the water flux due to concentration polarization.. In addition, the TFC membrane was found to show an enhanced level of water flux compared to the CTA membrane over the same draw solution concentration due to improved water permeability. The TFC membrane with 2 M of NaCl was selected for further concentrating the NF permeates. Concentration using TFC FO membranes resulted in an increase the active alkali between 0.5% - 0.6%. The cleaning effectiveness of the recovered cleaning agents was assessed using Quartz Crystal Microbalance with Dissipation (QCM-D). The cleaning agents recovered by 4 kDa/200 Da NF and FO were found to present no significant difference as compared to fresh cleaning agents.

Dairy wastewater treatment using Monoraphidium sp. KMC4 and its potential as hydrothermal liquefaction feedstock

Monoraphidium sp. KMC4 was cultivated mixotrophically for simultaneous treatment of dairy wastewater and biomass production. The KMC4 was cultivated with varying chemical oxygen demand concentrations of simulated synthetic dairy wastewater. Monoraphidium sp. KMC4 outperformed in 50% strength with biomass concentration of 1.47 g L-1. A significant change in biomass of 3.69 g L-1 was achieved after maintaining the pH of algal culture. The nutrient consumption promoted microalgal growth in the form of biomass productivity (122 mg L-1 day−1), accumulation of carbohydrate (28.73±1.6 wt%), protein (48.50±1.3 wt%), and lipid (20.29±2.3 wt%). This strain showed efficacious performance in treating simulated synthetic dairy wastewater obtaining biomass for various applications. The algal biomass derived from wastewater reported a significant volatile matter content and higher heating value. The biomass demonstrates satisfactory thermal degradation behavior which reveals its feasibility as feedstock for thermochemical conversion to biocrude. The integration of biomass production in high-scale raceway pond along with biocrude production is a promising pathway toward the generation of green energy for replacing traditional fossil fuels..

Integration of microalgae cultivation and anaerobic co-digestion with dairy wastewater to enhance bioenergy and biochemicals production

A sequential anaerobic digestion and phycoremediation process was employed to recover nutrients and remove pollutants from dairy wastewater (DW), while simultaneously producing biomethane and biochemicals. Anaerobic digestion of 100% DW achieved a methane content and production rate of 53.7% and 0.17 L/L/d, respectively. This was accompanied by the removal of 65.5% chemical oxygen demand (COD), 86% total solid (TS), and 92.8% volatile fatty acids (VFAs). The anaerobic digestate was then used to grow Chlorella sorokiniana SU-1. Using 25% diluted digestate as the medium, SU-1 could reach 4.64 g/L biomass concentration, with total nitrogen (TN), total phosphorus (TP) and COD removal efficiencies of 77.6%, 87.1% and 70.4%, respectively. The obtained microalgal biomass (contained 38.5% carbohydrates, 24.9% proteins, 8.8% lipids) was used to co-digest with DW, resulting in good methane production performance. Co-digestion with 25% (w/v) algal biomass obtained a higher CH4 content (65.2%) and production rate (0.16 L/L/d) than other ratios.

Continuous-Flow Aerobic Granular Sludge Treatment of Dairy Wastewater

The authors conducted a study on treating synthetic dairy wastewater using aerobic granular sludge (AGS) in a laboratory-scale continuous flow reactor (CFR) system. The system consisted of an anaerobic reactor, an aerobic reactor, and a settling sedimentation tank, with different hydraulic retention times tested over a 90-day period. The study monitored sludge characteristics and effluent treatment performance and found that the system achieved excellent removal rates for chemical oxygen demand and total carbon, exceeding 90%. As a result, the effluent met Portuguese laws for direct release into the water environment. Moreover, the study found that the AGS system improved the sludge sedimentation capacity from 272 to 80 mL/g, demonstrating its effectiveness as a viable treatment alternative for this type of effluent.

Effects of wastewater pre-treatment on clogging of an intermittent sand filter

Intermittent sand filters (ISFs) are widely used in rural areas to treat domestic and dilute agricultural wastewater due to their simplicity, efficacy and relative low cost. However, filter clogging reduces their operational lifetime and sustainability. To reduce the potential of filter clogging, this study examined pre-treatment of dairy wastewater (DWW) by coagulation with ferric chloride (FeCl3) prior to treatment in replicated, pilot-scale ISFs. Over the study duration and at the end of the study, the extent of clogging across hybrid coagulation-ISFs was quantified, and the results were compared to ISFs treating raw DWW without a coagulation pre-treatment, but otherwise operated under the same conditions. During operation, ISFs receiving raw DWW recorded higher volumetric moisture content (θv) than ISFs treating pre-treated DWW, which indicated that biomass growth and clogging rate was higher in ISFs treating raw DWW, which were fully clogged after 280 days of operation. The hybrid coagulation-ISFs remained fully operational until the end of the study. Examination of the field-saturated hydraulic conductivity (Kfs) showed that ISFs treating raw DWW lost approximately 85 % of their infiltration capacity in the uppermost layer due to biomass build-up versus 40 % loss for hybrid coagulation-ISFs. Furthermore, loss on ignition (LOI) results indicated that conventional ISFs developed five times the organic matter (OM) in the uppermost layer compared to ISFs treating pre-treated DWW. Similar trends were observed for phosphorus, nitrogen and sulphur, where proportionally higher values were observed for raw DWW ISFs than pre-treated DWW ISFs, with values decreasing with depth. Scanning electron microscopy (SEM) showed a clogging biofilm layer on the surface of raw DWW ISFs, while pre-treated ISFs maintained distinguishable sand grains on the surface. Overall, hybrid coagulation-ISFs are likely to sustain infiltration capacity for a longer period than filters treating raw wastewater; therefore, requiring smaller surface area for treatment and minimal maintenance.