Develop an integrating coagulation and RO systems to treat highly turbid water using synthesized coagulants

In the present study coagulation process was used as pretreatment for the RO membrane with turbid raw water collected from Bisalpur Dam, Rajasthan, India. To optimize coagulation performance, three kinds of coagulants, namely, Alum (commercially available), synthesized inorganic polymeric coagulant-medium basicity (IPC-M), and inorganic polymeric coagulant-ultra high basicity (IPC-UH) were examined for turbidity removal with varying operating parameters. It was observed that in the optimum pH range of 6–7, the IPC-UH resulted as the best performing coagulant with 0.99 mg/L equivalent Al2O3 dose revealing 2 NTU residual turbidity and residual aluminium of 0.001 mg/L. Moreover, Langelier saturation index and Ryznar stability index values were evaluated at optimum conditions of all the three coagulants proclaiming negligible scaling potential. Furthermore, the coagulant-treated water (100 L) was fed to the RO membrane, and the performance was noted in terms of flux, pressure, and TDS. It was observed that IPC-UH has the lowest reduction in permeate flux of 0.78 L/min/m2 compared to commercially available coagulant alum (0.90 L/min/m2). Also, the increased feed pressure was observed for all the coagulants treated water with the lowest value of 2.3 kg/cm2 for IPC-UH, which was 2.5 kg/cm2 for Alum (commercially available coagulant). Henceforth, integration of coagulation before the RO system resulted in effective pretreatment of turbid water with very minute scaling.

Assessment of Moringa oleifera Seeds as a Natural Coagulant in Treating Low Turbid Water

This research examined the coagulating potential of Moringa oleifera seeds in treating low turbid water. The active ingredient of the seeds was extracted using Soxhlet Apparatus with hexane as the solvent, after which the coagulant was dosed from 0.03g/L to 0.4g/L and used to treat a water sample with a low Turbidity of 18.4NTU, yielding an optimum value of 4.90NTU, an optimum dose of 0.03g/L and a turbidity reduction of 100% when compared with the World Health Organization (WHO) standard which is 5NTU. The study affirms Moringa oleifera as an effective natural coagulant in low turbid water treatment and it is recommended for household water treatments. Keywords— Hexane, Low turbid water, Moringa oleifera, Natural coagulant, Soxhlet apparatus

Effects of storage of Moringa oleifera seed powder on turbidity removal from medium turbid water

No Abstract.

Turbid Water Treatment Using Deshelled Carica papaya Seed: Analysis Via Factorial Design

Natural coagulants are proven to be a good alternative to conventional coagulants with the removal of various pollutants and are environmentally friendly. Despite its advantages, the least studies were carried out on local agro-wastes such as papaya seeds as natural coagulants concerning different operational factors. The study analyzes the main and interactions effect between the coagulant dosage, initial turbidity, and pH on deshelled Carica papaya seeds for turbid water treatment. A 2-level factorial design was used to investigate the main and interaction effects of the main operational factors, viz. coagulant dosage (50-200 mg/L), pH (3-7), and initial turbidity (100-500 NTU) on the turbidity removal of the synthetic turbid water. Based on individual performance, the results suggested that initial turbidity and pH are the most significant factors among the investigated operational factors. In combination, all interactions are significant, but the interaction between initial turbidity and pH is most significant, with 97.2% turbidity removal. Upon application of Carica papaya seed as a natural coagulant in water and wastewater treatment, these operating variables and their interactions are best to be considered.

EVALUATION OF DELONIX REGIA SEEDS AS A NATURAL COAGULANT IN THE TREATMENT OF LOW TURBID WATER

This research aims at evaluating the effectiveness of Delonix regia as a natural coagulant in treating low turbid water. The active ingredient of the coagulant was extracted using Soxhlet Apparatus with Hexane as the solvent. The water sample was obtained from the famous Ala river in Akure, Ondo state. The water from this river is oftentimes used by the residents without treatment because it appears clean to them, this river had a turbidity of 18.4NTU which is above the standard (5NTU) required by the World Health Organization (WHO) for safe usage. After treating with different doses (0.03g/L to 0.4g/L) of the coagulant, an optimum value of 6.12NTU at an optimum dose of 0.03g/L and a turbidity reduction of was obtained 66.74%, alongside an improvement in other water parameters such as Conductivity, dissolved oxygen and total dissolved solids. This result proves the effectiveness of Delonix regia as a natural coagulant in treating low turbid water. However, treatment with Delonix regia is not sufficient to improve the quality of low turbid water to WHO acceptable limits for potable water.

Underwater Light Characteristics of Turbid Coral Reefs of the Inner Central Great Barrier Reef

Hyper-spectral and multi-spectral light sensors were used to examine the effects of elevated suspended sediment concentration (SSC) on the quantity and quality (spectral changes) of underwater downwelling irradiance in the turbid-zone coral reef communities of the inner, central Great Barrier Reef (GBR). Under elevated SSCs the shorter blue wavelengths were preferentially attenuated which together with attenuation of longer red wavelengths by pure water shifted the peak in the underwater irradiance spectrum ~100 nm to the less photosynthetically useful green-yellow waveband (peaking at ~575 nm). The spectral changes were attributed to mineral and detrital content of the terrestrially-derived coastal sediments as opposed to chromophoric (coloured) dissolved organic matter (CDOM). A simple blue to green (B/G, λ455:555 nm) ratio was shown to be useful in detecting sediment (turbidity) related decreases in underwater light as opposed to those associated with clouds which acted as neutral density filters. From a series of vertical profiles through turbid water, a simple, multiple component empirical optical model was developed that could accurately predict the light reduction and associated spectral changes as a function of SSC and water depth for a turbid-zone coral reef community of the inner GBR. The relationship was used to assess the response of a light sensitive coral, Pocillopora verrucosa in a 28-d exposure laboratory-based exposure study to a daily light integral of 1 or 6 mol quanta m2. PAR with either a broad spectrum or a green-yellow shifted spectrum. Light reduction resulted in a loss of the algal symbionts (zooxanthellae) of the corals (bleaching) and significant reduction in growth and lipid content. The 6 mol quanta m2 d−1 PAR treatment with a green-yellow spectrum also resulted in a reduction in the algal density, Chl a content per cm2, lipids and growth compared to the same PAR daily light integral under a broad spectrum. Turbid zone coral reef communities are naturally light limited and given the frequency of sediment resuspension events that occur, spectral shifts are a common and previously unrecognised circumstance. Dedicated underwater light monitoring programs and further assessment of the spectral shifts by suspended sediments are essential for contextualising and further understanding the risk of enhanced sediment run-off to the inshore turbid water communities.