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The purpose of this paper is to present a comparative study between two low‐cost turbidimeter designs using a multi purpose Optical Fiber NIR System (OF‐NIRS), Optical Fiber NIR System‐Modified (OF‐NIRS‐M) and High Sensitivity NIR System (HS‐NIRS) conducted in the development of a turbidimeter by closely replicating the existing standard design guideline. Optical method is a typical measuring technique that has been applied intensively for the measurement of water turbidity.

Comprehensive guidelines for the development of turbidimeter have been stated by the United States Environmental Protection Agency (EPA Method 180.1) and the International Organization for Standardization (ISO 7027) and have been used as standards by instrument's manufacturers world wide, including the designs presented in this work. The development commonly does not only establish through physical instrumentation aspects, but also emphasizes on the physics of light‐matter interaction such as scattering and absorption that is embedded within the science of turbidity. The individual system design is the assembly of light emitting diode (LED) and photo detector with near infrared (NIR) band, amplifier, 12‐bit analogue to digital converter (ADC) and Basic Stamp 2pe microcontroller.

The measurement by OF‐NIRS produces coefficient of determination, R2=0.8881 with standard error of 20.33 NTU while HS‐NIRS produces higher precision result with R2=0.995 with standard error of 1.809 NTU. A modified version of OF‐NIRS (OF‐NIRS‐M) has been introduced and consists of direct emission of NIR radiation to the sample. OF‐NIRS‐M produces R2=0.9921 with standard error of 2.37 NTU, a high linearity result, comparable to HS‐NIRS.

This research introduced a fundamental design of a turbidimeter by following closely to the existing standards at much lower cost. This work presents a comparative study between two main designs that utilize different types of photo detector and amplification circuitry and enables related industry to develop their own in‐house turbidity monitoring system with flexible sensitivity.

This paper aims to present a review of the design and development of the turbidimeter for measuring the turbidity level in water. Monitoring the turbidity level of water is important because it is related to public health.

A precise and reliable turbidimeter can provide vital data that reveals the water condition level. Several turbidimeter units are discussed briefly. Three types of turbidimeter design – single beam, ratio and modulated four beams – are elaborated with some illustrations of the design concept. Various improvements and innovations for upgrading turbidimeter design are also discussed.

This paper elaborated on a new method of estimating the water turbidity level in water samples using an optical tomography system based on the independent component analysis method. The results showed that a tomography-based turbidimeter can measure slight changes in the level of turbidity when the volume of contaminants is changed slightly. The turbidimeter can also provide a profile of the distribution of the turbidity in the water sample.

A turbidimeter based on the optical tomography concept can be a valuable tool in determining the level of pollution in rivers, sea, etc.

Sediment measurement is usually accessible on a periodic or distinct basis. The measurement of sediment (suspended and bedload), especially in the field, is vital in keeping essential data of sediment transport and deposition. Various techniques for measuring sediment have been used over time each with its merits and demerits. The techniques discussed in this paper for suspended sediment include bottle, acoustic, pump, laser diffraction, nuclear and optical. Other techniques for bedload measurement are; River bedload trap (RBT), CSU/FU bedload trap, Helley–Smith, Polish Hydrological Services (PIHM) device, pit and trough, vortex tube, radioactive traces and bedload–surrogate technologies. However, the choice of technique depends on multiple factors ranging from budget constraint, availability of equipment, manpower and data requirement. The purpose of this paper is to present valuable information on selected techniques used in sediment measurement, to aid researchers/practitioners in the choice of sediment measurement technique.

This paper presents a general review of selected field techniques used in sediment measurement (suspended and bedload). Each techniques mode of operation, merits and demerits are discussed.

This paper highlights that each technique has its peculiar merits and demerits. However, two techniques are generally preferred over others; the bottle sampling and the Helley–Smith sampler for measuring suspended and bedload sediment. This is because the applicability of these techniques is quite widespread and time-tested.

This review paper provides an in-depth description and comparison of selected existing field sediment measurement techniques. The objective is to ease decision-making about the choice of technique, as well as to identify the suitability and applicability of the chosen technique.

Advancements in real-time water monitoring technologies permit rapid detection of water quality, and threats from waste loads. Water Framework Directive mandating the establishment of Member States’ water resources monitoring, presence of hazardous contaminants in effluents, and perception of vulnerability of water distribution system to attacks, have spurred technical and economic interests. The paper aims to discuss these issues.

As alternative to traditional analyzers, chemosensors, operate according to physical principles, without sample collection (online), and are capable of supplying parameter values continuously and in real-time. Their low selectivity and stability issues have been overcome by technological developments. This review paper contains a comprehensive survey of existing and expected online monitoring technologies for measurement/detection of pollutants in water.

The state-of-the-art in online water monitoring is presented. Application examples are reported. Monitoring costs will become a lesser part of a water utility budget due to the fact that automation and technological simplification will abate human cost factors, and reduce the complexity of laboratory procedures.

An overview of applicable instrumentation, and forthcoming developments, is given. Technological development in this field is very rapid, and astonishing advances are anticipated in several areas (fingerprinting, optochemical sensors, biosensors, molecular techniques). Online monitoring is becoming an ever-important tool not only for compliance control or plant management purposes, but also as a useful approach to pollution control and reduction, minimizing the environmental impact of discharges.

The purpose of this paper is to investigate the performance of biochar and fine filtralite as a polishing filter material in further removing organic matter, phosphorous, nitrogen, turbidity and indicator microorganisms from effluents of a compact greywater treatment plant (GWTP).

A filtration experiment was carried out using columns filled with biochar and fine filtralite as filter material and unfilled column as a control. The effluent from the GWTP was pumped using a peristaltic pump at a rate of 280 l/m2-d and was fed in upward flow into the columns. The quality parameters of the raw greywater, effluents from the GWTP and the polishing columns were studied for six months of operation period.

The results indicate that the process of polishing considerably improved the effluent quality of the system. Biochar performed best in removing organic matter, total N, turbidity and odor. Filtralite was superior in removing P. The contribution of the polishing step in removing total coliform bacteria (TCB) and Escherichia coli (E. coli) was remarkable. Additional log reduction of 2.18, 2.26 and 1.81 for TCB and 2.26, 2.70 and 2.01 for E. coli was obtained compared to the GWTP due to biochar, filtralite and control column, respectively.

This study demonstrates the opportunities for improving the performance of decentralized greywater treatment systems by integrating locally available polishing materials to achieve a better quality effluent.

The present study identifies efficient polishing system for decentralized and compacted greywater treatment system. The recommended polishing materials potentially improve the quality of effluents and add social, economic and environmental values.

States that the presence of Cryptosporidium oocysts in potable water supplies continues to be a high profile problem in the UK and the USA, causing concern among public health officials and those responsible for water treatment. Reviews the current status of knowledge about this troublesome parasite and considers water treatment options.

Biofilms are bacterial communities embedded in exopolysaccharide, enhancing the difficulty of detaching bacterial cells from surfaces. Due to structural properties, it is difficult to detach biofilms. Many removal methods have been developed, but there are still some limitations such as sample size and reproducibility. “Spindle” was developed, producing a higher quality suspension which can be used for further study. The paper aims to discuss these issues.

The authors compared the enumeration of biofilm-forming cells detached from the spindle and stomacher in various surfaces. First, the authors chose stainless steel and polyvinyl chloride to attach biofilms and to be subjected to stomacher and spindle for up to 2 min. Also, the authors evaluated the efficiency of detachment from vegetable surfaces.

In a comparative experiment of abiotic surfaces, the spindle showed identical effectiveness for detaching biofilm-forming cells compared to the stomacher, recovering the population by 8-log for Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes. The spindle also showed no significant difference from the stomacher in the number of recovered cells which is 4-log from vegetable surfaces. However, turbidity after spinach was subjected to spindle was 4.37 NTU, while it was 99 NTU for stomacher, which was in accord with visual result about clearance.

This study demonstrated that the spindle is a useful to separate biofilms from surfaces without destructing structure, and thus it can be used for analysis in food laboratories as well as utilized for vegetable washing step in the food industry.

Optoacoustic spectroscopy is a completely new technique for the examination of solid and liquid samples and a system for this is now commercially available in the UK in the form of EDT's Model OAS 400 Opto‐Acoustic Spectrometer. This attrac‐tive instrument has been developed at EDT Research, 14 Trading Estate Road, London NW10 7LU, with the backing of the National Research Development Corporation from the pioneering work in the field by Dr G. F. Kirkbright of Imperial College, London. The principles of OAS rest on the fact that light absorbed by a solid sample is converted to heat with the sample. If the sample is sealed in a small cell containing a gas e.g. air or nitrogen the heat will be transferred to the gas and cause it to expand. If the incident light beam is now chopped at a steady rate, the gas in the cell will be alternately heated and cooled leading to a series of pressure pulses which can be detected by microphone. Scanning the wave‐length of the light and recording the associated sound amplitude leads to an absorption spectrum analogous to that of more conventional methods of spectrometry. The advantages of OAS lie in the fact that spectra of opaque substances, powders, polymers, suspensions and slurries can be made without difficulties arising from lack of transmission, scattering or reflection.

Coag-flocculation behavior of Brachystegia eurycoma coagulant (BEC) in respect of pH variation in coal washery effluent has been investigated at room temperature using various dosages of unblended BEC. Coag-flocculation parameters such as order of reaction α, rate constant (K and Ks), coagulation period, τ_1/2 e.t.c were determined. Turbidity measurement was employed using the single angle nephelometric method while BEC processing was based on work reported by Adebowale and Adebowale. Maximum parameter values are recorded at K of 6.6667×10^-3m³/kg.s; dosage of (0.2 and 0.4kg/m³), pH2 and τ_1/2 of 1.7293s while the minimum values are recorded at 5.00×10^-4m³/kg.s, dosage of 0.3kg/m³, pH 6 and τ_1/2 of 23.0572s. Minimum value of coag-flocculation efficiency is >98%; thus establishing BEC as a potential effective coag-flocculant. Parameters obtained lie within the range of previous works and confirm that the theory of perikinetics holds for coag-flocculation of the coal washery effluent using BEC at the experimental conditions.