Removal Of Suspended Solids Research Articles

Chitosan of blood cockle shell (Anadara granosa) as a natural coagulant for removal of total suspended solids (TSS) and turbidity of well-water

Blood clam or blood cockle (Anadara granosa) is a clam species with high calcium carbonate (CaCO3) and chitin content; these compounds are commonly used in coagulation water treatment. This study examined the capacity of blood cockle shells (BCS) as an innovative natural coagulant in the form of unmodified powder (BCSP) and chitosan extracted from the shells (BCSC) to reduce TSS and turbidity of well-water. SEM and FTIR analysis were conducted to analyse the characteristics of the media. The coagulant dose, pH of the water sample, and settling time were investigated using a jar test experiment to determine the optimum condition for each experimental system. Rapid mixing (1 min at 120 rpm) was followed by slow mixing (10 min at 60 rpm), followed by settling times ranging from 10 to 30 min. The optimum settling time was 30 min, after which 76% TSS and 76% turbidity were removed using 75 mg/l of BCSP at pH 4. The tests with BCSC resulted in 80% TSS and 81% turbidity removal with 200 mg/l of BCSC at pH 5 and a settling time of 30 min. The results were compared to the performance of alum (Al2(SO4)3·18H2O), a commercial chemical coagulant. Under similar dosage (200 mg/L) and pH (= 6) conditions, alum reduced turbidity and TSS by 95% and 97%, respectively. These results indicate that blood cockle shell-based coagulant is a promising environmental-friendly material that can compete and possibly replace conventional chemical coagulants in water treatment systems.

Selective removal of ultrafine suspended solids during organic pollutant degradation by a MoS2/graphene oxide sponge

Selective removal of ultrafine suspended solids during organic pollutant degradation by a MoS2/graphene oxide sponge

A comparison study of heat-assisted Fe2+/persulfate and powdered activated carbon/persulfate wastewater pre-treatment for membrane fouling alleviation

Heat/Fe2+/persulfate (PS) and heat/powdered activated carbon (PAC)/PS exhibit oxidation, coagulation, and adsorption effects, respectively. However, no studies have been conducted to discuss and compare the synergistic contribution to membrane fouling mitigation under thermal synergy. Herein, heat/Fe2+/PS and heat/PAC/PS systems were used to alleviate membrane fouling during municipal wastewater recycling in an aerobic granular sludge membrane bioreactor (AGMBR), and the effects of oxidation, coagulation, and adsorption on the membrane fouling mitigation were analyzed. The results showed that heat/Fe2+/PS and heat/PAC/PS effectively increased the filtration flux, decreased the fouling resistance, and maintained the membrane surface morphology. Compared to heat/PAC/PS, the heat/Fe2+/PS exhibited better control of membrane fouling owing to the generation of sulfate radicals and Fe3+. The non-radical effect is an important way to mitigate membrane fouling by heat/PAC/PS. Moreover, the pretreatment systems were effective in decomposition and removal of large-particle-size pollutants owing to their excellent oxidation capacity. According to the extended Derjaguin–Landau–Verwey–Overbeek theory, the heat/Fe2+/PS system had the higher energy barrier values of foulant–membrane (155.31 kT) and foulant–foulant (113.75 kT). The cake filtration and intermediate blocking models were the major mechanisms of membrane fouling, and efficient removal of chemical oxygen demand (R2>0.93) and suspended solids (R2>0.92) were beneficial to the membrane fouling mitigation. This study elucidates the differences in the mechanisms of heat/Fe2+/PS and heat/PAC/PS in mitigating AGMBR membrane fouling.

An Inexpensive, Reproducible Method to Quantify Activated Sludge Foaming Potential: Validation through Lab-Scale Studies and Year-Long Full-Scale Sampling Campaign.

Activated sludge is a conventional treatment process for biochemical oxygen demand (BOD) and total suspended solids (TSS) removal at water resource recovery facilities (WRRFs). Foaming events are a common operational issue in activated sludge and can lead to decreased treatment efficiency, maintenance issues, and potential environmental health risks. Stable foaming events are caused by biological and chemical drivers (i.e., microbes and surfactants) during the aeration process. However, foaming events are difficult to predict and quantify. We present an inexpensive and easy-to-use method that can be applied at WRRFs to quantify foaming potential. Subsequently, the method was applied over a year long full-scale study while data on microbial community composition and functional parameters associated with foaming potential were collected from activated sludge samples at South Shore Water Reclamation Facility (WRF) (Oak Creek, WI). Results from the development of the foaming potential method using linear alkylbenzene sulfonate (LAS) showed that the method was reproducible (relative standard deviation < 20%) and able to capture changes in foam inducing constituents. Using full-scale activated sludge samples, higher relative abundance values for the following genera were associated with foaming events: Zoogloea, Flavobacterium, Variovorx, and Bdellovibrio. This is the first report that Variovorx and Bdellovibrio relative abundance was correlated with foaming events in activated sludge. Furthermore, the foaming potential positively correlated (p ≤ 0.05) with soluble total nitrogen. Characterizing foaming events through frequent sampling, and monitoring of specific genera and functional parameters may allow for predictions and preemptive mitigation efforts to avoid negative consequences in the future.

Physico-chemical characteristics and biodegradability of primary effluent and particulate matter removed by microscreens.

In this study, the physical, chemical, and biological characteristics of raw wastewater were compared with the liquid and solid streams generated by a primary clarifier (PC), a rotating belt filter (RBF, 350 μm), and a drum filter (DF, 60 μm) and series (SER) combination of an RBF with a PC or a DF using pilot-scale primary treatment units. The RBF removed about 36% of the influent total suspended solids. The DF and PC yielded an influent total suspended solid removal of 47% to 55% in both individual (parallel) and SER configurations. The size fractionation and chemical characterizations of the liquid fractions indicated a significant change in the wastewater composition in both filter configurations with no variation in the biodegradability of liquid fractions. The solids recovered by RBF had a higher total solids (TS) concentration and a higher volatile solids (VS) content (0.92 g VS/g TS) than that of DF and PC treatments (0.58 to 0.84 g VS/g TS). DF and PC sludge demonstrated a higher biodegradability rate (k1 ; 0.11 d-1 < k1 < 0.20 d-1 ) than solids recovered by RBF (0.09 d-1 ). The retained solids in the SER configuration demonstrated a significantly lower theoretical biochemical methane potential than the parallel configuration, likely due to the presence of smaller particles with a significantly higher ratio of particulate chemical oxygen demand over volatile suspended solids (1.86 to 2.40 g chemical oxygen demand/g volatile suspended solids). These results indicated that the physical, chemical, and biological characteristics of liquid and solids from different filter configurations are required to determine design criteria to upgrade or retrofit water resource recovery facilities using an RBF or a DF. PRACTITIONER POINTS: A rotating belt filter (RBF) removed less solids than a drum filter (DF) or a primary clarifier (PC). A series configuration of an RBF with either a DF or PC resulted in an effluent with a lower proportion of slowly biodegradable organic matter than in a parallel configuration. Solids from an RBF, a DF, or a PC had similar theoretical biochemical methane potential.

Staircase Wetlands for the Treatment of Greywater and the Effect of Greywater on Soil Microbes

Fresh water is an increasingly scarce resource in both urban and rural development. As a response to this challenge, non-potable water reuse is on the rise. This research explored a potential off-grid system for water purification, consisting of a staircase wetland with terracotta pot plants working as a filter for greywater. This study further investigated the physicochemical properties of greywater and the soil before and after wetland purification. The removal of total suspended solids, total coliforms, fecal coliforms, etc., was always between 90 and 99%. Results show that the filtered water satisfied all requirements for water reuse, e.g., a pH of 7–7.5 and a turbidity &lt; 5 NTU. This research then uniquely investigated the effect of greywater on soil microbes and soil biomass using soil DNA extraction and the tea bag index testing method. The filtered greywater absorbed by soil decomposed the soil faster (66% for green tea) and stabilized it better compared to tap-water-absorbed soil or unfiltered greywater. DNA generation sequencing revealed no significant differences in alpha diversity between the control and treatment samples. The beta diversity differences were significant. This nature-based solution can lead to reduced loads on the sewage system, resulting in less wastewater generation.

Turbidity removal and pH of raw water treated with natural coagulants

Concerns regarding water pollution and scarcity have led researchers to investigate new sustainable water treatment technologies, such as the use of natural coagulants, that can be used for water treatment in decentralized locations at small rural communities, as these materials can be used in compact water treatment plants. Thus, the present study evaluated the use of natural coagulants, drumstick tree seeds and tannins extracted from black acacia, in water treatment to remove turbidity. To determine the ideal coagulant dosage, jar tests were performed, followed by filtration to remove the formed sludge. pH and turbidity were analyzed to compare the coagulants efficiency. The natural coagulants achieved satisfactory removal of suspended solids, completely removed turbidity, and causing no significant changes in pH, unlike aluminum sulfate, hence, these natural materials can be used as an alternative to chemical coagulants.

Polymer-flooding produced water treatment using an electro-hybrid ozonation-coagulation system with novel cathode membranes targeting alternating filtration and in situ self-cleaning

Polymer-flooding produced water is more difficult to treat for reinjection compared with normal produced water because of the presence of residual hydrolyzed polyacrylamide (HPAM). A novel cathode membrane integrated electro-hybrid ozonation-coagulation (CM-E-HOC) process was proposed for the treatment of polymer-flooding produced water. This process achieved in situ self-cleaning by generated microbubbles in the cathode membrane. The CM-E-HOC process achieved a higher suspended solid (SS), turbidity and PAM removal efficiency than the CM-EC process. The SS in the CM-E-HOC effluent was ≤ 20 mg/L SS, which met the reinjection requirements of Longdong, Changqing Oilfield, China (Q/SYCQ 08,011–2019) at different current densities (3, 5 and 10 mA/cm2). The CM-E-HOC process greatly mitigated both reversible and irreversible membrane fouling. Therefore, excellent flux recovery was obtained at different in situ self-cleaning intervals during the CM-E-HOC process. Furthermore, alternating filtration achieved continuous water production during the CM-E-HOC process. On one hand, the effective removal of aromatic protein-like substances and an increase in oxygen-containing functional groups were achieved due to the enhanced oxidation ability of the CM-E-HOC process, which decreased membrane fouling. On the other hand, the CM-E-HOC process showed improved coagulation performance because of the increased oxygen-containing functional groups and polymeric Fe species. Therefore, larger flocs with higher fractal dimensions were generated, and a looser and more porous cake layer was formed on the membrane surface during the CM-E-HOC process. Consequently, the CM-E-HOC process exhibited better in situ self-cleaning performance and lower filtration resistance than the CM-EC process.

Pretreatment of Slaughterhouse Effluent Treatment Plant Sludge Using Electro-Fenton Process for Anaerobic Digestion

Sludge management is an integral process of an effluent treatment plant (ETP). This study aimed at using the electro-Fenton (EF) process for pretreatment of a cattle-based slaughterhouse ETP sludge to enhance biogas production from anaerobic digestion. EF-oxidation experiments were conducted in 0.5 L beakers with mild-steel electrodes, to study the effect of factors, viz., H2O2 concentration, current density and reaction time on soluble chemical oxygen demand (sCOD) concentration, soluble extracellular polymeric substances (sEPS) concentration and volatile suspended solids (VSS) removal efficiency. This was followed by the quantification of biogas production from the raw and pretreated sludge in anaerobic digestion (AD). Experimental conditions for the EF process were optimized using response surface methodology (RSM). At optimized experimental conditions, EF pretreatment resulted in an increase in sCOD and sEPS concentrations, from 0.91 g/L to 6.1 g/L and 0.18 g/L to 1.4 g/L, respectively. VSS removal efficiency was 68.1%. Batch anaerobic digestion studies demonstrated an enhancement in the specific biogas yield, from 110 NmL/g-VS to 460 NmL/g-VS.

The potential of decentralised wastewater treatment in urban and rural sanitation in South Africa: lessons learnt from a demonstration-scale DEWATS within the eThekwini Municipality

The design principles of decentralised wastewater treatment systems (DEWATS) make them a practical sanitation option for municipalities to adopt in fast-growing cities in South Africa. Since 2014, a demonstration-scale DEWATS with a modular design consisting of a settler, anaerobic baffled reactor (ABR), anaerobic filter (AF), vertical down-flow constructed wetland (VFCW) and horizontal flow constructed wetland (HFCW) has been in operation in eThekwini. A performance evaluation after the long-term operation was undertaken in 2019 by comparing the final effluent with national regulatory requirements. Despite limitations in characterising the raw wastewater, a comparison of the settler and final effluent quality indicated high (≥ 85%) removal efficiencies of total chemical oxygen demand (CODt), ammonium-N (NH4-N) and orthophosphate-P (PO4-P), 75% removal of total suspended solids (TSS) and 83.3% log10 removal of Escherichia coli. Lack of exogenous and endogenous carbon and high dissolved oxygen (DO) concentrations (&gt; 0.5 mg‧L−1) inhibited denitrification in the HFCW, resulting in 12.5% of the effluent samples achieving compliance for nitrate-N (NO3-N). Moreover, mixed aggregate media and low residence times in the HFCW may have also contributed to poor NO3-N removal. During the COVID-19 lockdown, an unexpected shutdown and subsequent resumption of flow to the DEWATS indicated a 16-week recovery time based on achieving full nitrification in the HFCW. Although design modifications are necessary for the HFCW, the installation of urine diversion flushing toilets at the household will reduce the nutrient loading to the DEWATS and potentially achieve fully compliant effluent. Alternatively, the application of two-stage vertical flow constructed wetlands to improve denitrification should also be explored in the South African context. With an improved design, DEWATS has the potential to fill the gap in both urban and rural sanitation in South Africa, where waterborne sanitation is still desired but connections to conventional wastewater treatment works (WWTWs) are not possible.

Management proposal of a naturally occurring wetland modeled as a constructed wetland

Environmental management and restoration aim to accelerate the recovery of ecosystems that have been affected by human activities. This paper presents the diagnosis and management proposal for the Valsequillo wetland, Puebla, Mexico. The study site is a natural wetland dominated by water hyacinth (Eichhornia crassipes) which performs a biofiltration process by reducing the pollutant load of the water. To increase the efficiency of the wetland, an annual harvest plan is proposed in this work. However, the ideal amount of biomass to harvest is unknown. In order determine the optimal annual harvest plan, this natural wetland was modeled as if it were a surface flow wetland by using the equations described. A total of 48 surface water samples were collected in three different seasons of the year (dry, rainy, and winter) and 34 water quality physicochemical parameters were measured. Additionally, two water quality indices were determined, namely: Overall Index Pollution (OIP) and Heavy Metal Evaluation Index (HEI) to determine the degree of contamination in different zones of the study area. The model results showed that in order to achieve the desired removal of total phosphorus (TP) or chemical oxygen demand (COD), 274 ha or 306 ha of aquatic plants must be harvested, respectively. The results of the modeling showed that this action will optimize the function of the wetland by improving the removal of total suspended solids (TSS, 6%), total nitrogen (TN, 24%) TP (31%), chemical oxygen demand (COD, 11%) and biochemical oxygen demand (BOD5, 101%).

Application of Centrifugation and Soilless Filtration Technologies in the Beer Production Process and Empirical Research on Their Impact on Beer Quality

By delving into the centrifugation and diatomaceous earth-free filtration techniques in various crucial aspects of beer production, this study aims to quantify their impacts on beer quality and environmental sustainability. Firstly, the effectiveness of these techniques in enhancing beer clarity and stability is compared through experiments, with a detailed analysis of their precision and chemical mechanisms in removing suspended particles. Additionally, their advantages in regulating beer taste and retaining flavor compounds are explored through sensory evaluation and chemical composition analysis. Most importantly, the focus is on sustainability and environmental friendliness, revealing the advantages of diatomaceous earth-free filtration techniques in reducing environmental burdens and carbon footprints through a comparison of filter material usage, waste generation, and energy efficiency. The results provide essential scientific evidence for the brewing industry to support its transition towards a more sustainable and eco-friendly direction. Centrifugation and diatomaceous earth-free filtration are two important innovations in modern brewing industry, playing a critical role in improving beer quality and production efficiency. In traditional beer production, the removal of suspended solids and liquid separation are crucial steps, and centrifugation and diatomaceous earth-free filtration technologies provide brewers with more precise and controllable tools. Centrifugation, as an efficient solid-liquid separation device, has been widely applied in the beer production process. It separates suspended yeast, proteins, and impurities from the fermenting liquid through centrifugal force, significantly enhancing beer clarity and stability. Furthermore, centrifugation can be used to control yeast concentration, thus influencing the flavor characteristics of beer, offering brewers more options for process control. Meanwhile, diatomaceous earth-free filtration is a revolutionary process that eliminates the use of traditional filter aids like silica or bone char, opting for more environmentally friendly and sustainable alternatives. This technology employs microfiltration membranes, nanomaterials, or other efficient filtration media to effectively remove suspended solids while retaining yeast and other beneficial components, thereby preserving beer’s texture and flavor characteristics.

EFFICIENT REMOVAL OF MAGENTA DYE FROM WATER BY BOTH NATURAL AND CHEMICAL COAGULANTS

Reactive magenta dye (RMD) has been removed from the aqueous solution by different coagulants such as natural coagulants Moringaoleifera (MO), Strychnos potatotrum (SP), and Alum chemical coagulants (AC) respectively. All these three coagulants were studied with various parameters to optimize the maximum removal %, like coagulant dosage from 10 ml to 60 ml, RMD concentration range of 100 mg/L to 500 mg/L, contact time between 10 min to 60 min, and pH kept neutral. The maximum percentage removal was achieved by SP coagulant at 60 min contact time, 100 mg/L dye concentration, and 60 ml coagulant dosage whereas MO and Alum achieved the maximum of 93% and 85% respectively. The results showed that MO seeds, SP seeds, and AC coagulants performed well in the removal of suspended solids and dye color. Furthermore, this research validated the preparation of low-cost eco-friendly coagulants and effective jar test methods for treating reactive dyes which are present in real textile water.

A Sustainable Approach for Removing Organic Pollutants from Food Processing Effluents Using Unmodified Cocopeat as an Adsorbent

Food production (chips) uses raw materials such as tapioca, cassava, banana, and many more, which contribute to excessive pollutants in the water. Thus, there is a need to treat effluent sufficiently to prevent undesired pollutants from being released into the receiving water bodies, such as rivers and agricultural drainage systems. This study aims to investigate the effectiveness of cocopeat in removing targeted parameters such as suspended solids (SS), chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), and total phosphorus (TP) from the chips processing effluent. Batch experiments were conducted to determine optimum operating parameters, including the adsorbent dosage, contact time, and shaking speed. This was done to identify the best removal rates of SS, COD, NH3-N and TP from effluent food processing samples taken from two different discharge points based on their usages. The experimental results show that at the optimum conditions of pH 7, cocopeat dosages of 800 mg/L, contact time of 30 minutes, and shaking speeds of 200 rpm, the unmodified cocopeat achieved 17.3% and 19.8% of SS removal, 35.5% and 28.9% of COD removal, 40.7% and 30.5% of NH3-N removal, and 53.5% and 59.2% of TP removal, from Point A and Point B effluent, respectively. Besides, the maximum adsorption capacity achieved by unmodified cocopeat towards SS (1.5-14.0 mg/g), COD (16.88-17.75 mg/g), NH3-N (0.31-0.32 mg/g) and TP (1.46-1.50 mg/g) are comparable to the adsorption capacities reported by previous researchers. This finding suggests that cocopeat could potentially replace the commercially developed adsorbents for the treatment. Furthermore, this study gave insights into the feasibility of sustainable treatment using cocopeat as an adsorbent for medium-strength effluent. However, it is suggested that further alteration of the cocopeat characteristics, either by chemical or physical modifications, and its sludge disposal methodcould be explored further to enhance the treatment performance.

Effect of Different Operational Conditions on the Treatment Performance of Milk Processing Wastewater (MPW) Using a Single Stage Flexible Fibre Biofilm Reactor (SS-FFBR)

The performance of a biofilm system, single-stage flexible fibre biofilm reactor (SS-FFBR) treating milk processing wastewater (MPW) is evaluated under various process and operational conditions. The system behavior is analyzed with different biological and physical parameters. Results show that the high COD removal efficiency of 95% is obtained at a low CODin concentration of 809 mg/L. However, the COD removal is slightly decreased to 91.7% once the CODin concentration incremented to nearly 4000 mg/L. The effect of organic loading rate (OLR) on the SS-FFBR performance is examined as total suspended solids removal efficiency, dissolved oxygen, and turbidity. The SS-FFBR showed considerable performance, so that 89.9% and 89.7% removal efficiencies in terms of COD and TSS removals, respectively, obtained at the highest OLR of 11.7 kg COD/m3d. TSS removal efficiency of 96.7% is obtained at a low OLR of 1.145 kg COD/m3d. A linear relationship between the OLR and COD removal rate was revealed. The COD removal rate was incremented from 1.08 to 10.68 kg COD/m3d as the OLR increased from 1.145 to 11.7 kg COD/m3d. Finally, the operating system is a promising technique recommended to treat various industrial wastewaters with high OLR.

Performance of sand filter with disc and screen filters in irrigation with rainbow trout fish effluent

AbstractDrip irrigation is the most suitable system for reusing effluents in agriculture, but emitter clogging is still its major drawback. Adequate filtration is needed to prevent emitter clogging, but little information is available about the performance of different filter types when using fish farm effluent. The purpose of this study was to evaluate the performance of three filtration treatments for rainbow trout effluent in drip irrigation systems: (1) sand filter (T1), (2) sand filter followed by a disc filter (T2) and (3) sand filter followed by a screen filter (T3). The treatments were tested with a constant discharge of 14.4 m3 h−1 at two working pressures of 300 and 150 kPa until reaching the backwashing threshold. For each filter, the following were computed: filtered volume per cross‐section until reaching the backwashing threshold (VB), filtered volume per cross‐section unit and head loss (V10), suspended solids removal efficiency (EF) and filter mass retention (q). T2 at 300 kPa had a significantly (p &lt; 0.01) higher VB, whereas T1 and T3 only showed a VB of 53% and 45% at 300 kPa and 48% and 47% at 150 kPa, respectively, higher than that obtained by T2. The results suggest that using a combination of sand and disc filters at an operation pressure of 300 kPa is the best option when using rainbow trout effluent.

Coagulation-Flocculation Process of Nutrient-Rich Suspended Solids from Aquaculture Effluent Using Bioflocculant

Due to the growth and development of the aquaculture industry, appropriate wastewater treatment is needed to reduce uncontrolled pollution and environmental impacts. Therefore, this research uses green technology method, which is the coagulation-flocculation process to treat aquaculture wastewater. Natural flocculants have been the focus of research of many research due to the negative impact from using chemical flocculant. In this study, the potentiality of local plants of moringa leaves and seed (Moringa oleifera), banana pith (Musa), neem leave (Azadirachta indica) and Pandan leave (Pandanus amaryllifolius) as bioflocculant were studied. This study also focuses on nutrient recovery. The potential of sludge obtained through the coagulation-flocculation process as fertilizer was investigated in comparison with commercial fertilizer. Through this study, it is shown that Moringa oleifera seed recorded the highest rate of suspended solid removal from synthetic kaolin water at 36.7% and highest turbidity removal rate at 34.8%. Previous studies have shown that aquaculture sludge contains 1.27 % of nitrate, 0.32 % of phosphorus and 0.65 % of potassium. The characteristics of sludge produced through the process of coagulation-flocculation resembles organic fertilizer. This shows that treated aquaculture sludge has potential to be used as an organic fertilizer. With this, it can promote the use of sustainable green technology for effective aquaculture wastewater treatment.

The role of heat/powdered activated carbon/persulfate in membrane fouling control in a coupled aerobic granular sludge–membrane system for municipal wastewater reclamation

This study proposed and applied an innovative heat/powdered activated carbon (PAC)/persulfate (PS) pre-treatment system for the first time in an aerobic granular sludge–membrane system (AGSMS). We examined the effects of the heat/PAC/PS system on membrane fouling mitigation and contaminant removal and qualitatively evaluated the contribution of adsorption and oxidation to membrane fouling control. Compared to other pre-treatment systems, the heat/PAC/PS system could enhance the removal of pollutants, reduce fouling resistance, and delay the decline of permeation flux, resulting in low foulant content on the membrane surface and formation of a loose and porous cake layer. According to radical scavenging experiments, the excellent heat/PAC/PS system pre-treatment performance was attributed to the PAC adsorption capacity and non-radical oxidation pathway. Thermal synergy played a significant role in promoting adsorption and oxidation abilities. The extended Derjaguin–Landau–Verwey–Overbeek theory indicated that the high-energy barrier in the heat/PAC/PS system was an important factor in inhibiting the adhesion of foulants to the membrane surface. Furthermore, the correlation analysis suggested that membrane fouling control should focus on the removal of chemical oxygen demand and suspended solids. This study provides a new approach for membrane fouling mitigation through AGSMS in municipal wastewater treatment.

Municipal wastewater treatment with corrugated PVC carrier anaerobic baffled reactor.

The anaerobic baffled reactor (ABR) is a promising solution for decentralized wastewater treatment due to its low operation cost as compared to the activated sludge process, but it requires comparatively higher hydraulic retention time (HRT). This ultimately increases land requirement, capital and construction cost of treatment plant. This study investigates performance of ABR using polyvinyl chloride (PVC) corrugated pipe as carrier media to improve biomass retention capacity and treatment performance of reactor with the aim to reduce HRT. Comparative performance of two ABRs with and without carrier media was analyzed under mesophilic conditions (35 ± 1 °C) for organics and total suspended solids (TSS) removal at HRTs of 24, 18, 12, 8, 6 and 4 h. Results showed that at HRTs of 24-08 h, the organics removal performance of the carrier anaerobic baffled reactor (CABR) was better than ABR and was in the range of 77-81% for CABR as compared to 64-70% for ABR. However, on further decrease in HRT to 6 h, CABR sustained the treatment with organics removal of 80%, while ABR performance reduced to 58%, creating a performance difference of 38%. Average total suspended solids (TSS) removal was in the range of 76-83% at all HRTs for both reactors. Therefore, this study identified CABR with PVC carrier media as an effective low-HRT reactor for organics and SS removal with less land area requirement.

Development of an improved solids-liquid separation reactor for floatable & settleable solids in DAF slurry of a slaughterhouse

The dissolved air flotation (DAF) is used widely for wastewater treatment as a primary treatment unit to remove suspended solids (SS) and oil & grease (O & G). However, the less studied part is the management of concentrated slurry from the DAF operation that exhibit both settling and floating nature. It is a common practise so far to further dewater the DAF slurry by decanting centrifuge. This study addresses the problems of dewatering the DAF slurry by developing a simple yet novel solid-liquid separation unit on a pilot scale and its implementation on a full-scale. The DAF slurry (SS:9100 ± 830 mg/L) contained settled and floating or suspended solids (SS) layers of 125 ± 9 and 130 ± 11 mL/L, respectively, and a distinct clear water zone of 744 ± 16 mL/L sandwiched between two. The solid-liquid separation was achieved using two reactors in series. In the first reactor, the settleable solids are separated and the overflow containing floatable suspended solids are taken to the second unit and clear water was recovered from the bottom of the reactor. The SS removal efficiency was ~95 % and the volume reduction of sluryy was 70 % at an overall hydraulic retention time (HRT) of 2 h. The rest of the thickened slurry has SS concentration of 32,174 to 33,866 mg/L indicating effective thickening. As a result of volume reduction, the operation time of decanting centrifuge was also reduced by 70 % and hence a total power saving of 77 to 117 kW/day (for slurry volume of 10 to 15 m3/day).