Conditioning of Sewage Sludge with Physical, Chemical and Dual Methods to Improve Sewage Sludge Dewatering

The paper presents the impact of different methods of sewage sludge conditioning on the improvement of sludge dewatering during pressure filtration processes. The following conditioning methods were tested for sludge preparation: sonication, addition of organic and inorganic chemicals (Zetag 8180, PIX 113 and the combined action of both substances). The research covered: physical and chemical analysis of sewage sludge, measurement of capillary suction time as an indicator of sludge dewaterability, some technical parameters of sludge pressure filtration process and the analysis of filtrate to assess the degree of contamination. The results of the research showed that the final water content of the prepared sludge decreased, while the specific filtration resistance increased. Among the tested methods the best results of sludge dewatering effects were obtained for sonicated sludge and its preparation with inorganic coagulant PIX 113. The combined effect of sonication with the addition of chemicals Zetag 8180 and PIX113 to sludge allowed for the reduction of organic substances, ammonium nitrogen and phosphates in filtrate after sludge dewatering.

Experimental Determination and Modeling of Desorption Isotherms of the Tomato "Lycopersicum esculentum"

The aim of this work is to make a contribution to the drying of tomatoes. The purpose of this contribution is the experimental determination of the desorption isotherms of a variety of tomato (one of the most widespread on the Burkinabe market place) using the static gravimetric method at temperatures of 25°C, 40°C and 50°C. It is more specifically a question of validating a theoretical model based on these experimental studies. Sorption isotherms allow us to have information to establish the stability of food products and their storage conditions. These isotherms are curves which give valuable information on the hygroscopic balance of a product because they allow to know its range of stability after drying by determining the final water content.

Cherry Tomato Drying: Sun versus Convective Oven

Solar drying and convective oven drying of cherry tomatoes (Solanum lycopersicum) were compared. The changes in the chemical parameters of tomatoes and principal drying parameters were recorded during the drying process. Drying curves were fitted to several mathematical models, and the effects of air temperature during drying were evaluated by multiple regression analyses, comparing to previously reported models. Models for drying conditions indicated a final water content of 30% (semidry products) and 15% (dry products) was achieved, comparing sun-drying and convective oven drying at three different temperatures. After 26–28 h of sun drying, the tomato tissue had reached a moisture content of 15%. However, less drying time, about 10–11 h, was needed when starting with an initial moisture content of 92%. The tomato tissue had high ORAC and polyphenol content values after convective oven drying at 60 °C. The dried tomato samples had a satisfactory taste, color and antioxidant values.

Non-isothermal moisture migration in a GCL composite liner system

Geosynthetic Clay liners (GCLs) are used extensively in waste management facilities as part of hydraulic and gas barriers since the bentonite, active component of GCLs, possesses a low conductivity when well hydrated. GCL hydration occurs in the unsaturated regime following the water retention curve of the GCL and subsoil (wetting and drying path of the WRC of the GCL and subsoil, respectively). Moreover, the GCL hydration is controlled/governed by factors such as applied stress condition, subsoil characteristics, and weather condition (temperature). This paper numerically studied the influence of temperature in the GCL hydration. The models were conducted using Vadose/W and simulations were calibrated with experimental results and further practical scenarios were then predicted. Five temperature conditions that resemble average and extreme weather were used (5°C, 10°C, 20°C, 50°C, 70°C, respectively). Results indicate that temperature influence the GCL hydration rate and the final water content achievable, which affect the final performance of the GCL.

Colour variation in immature coffee dried under different dry bulb and dew point temperature conditions

This study evaluated colour variation as a function of the drying kinetics of immature coffee subjected to different drying conditions. Additionally, mathematical models were fitted to experimental data for green coffee berries dried in a thin layer under different drying conditions, besides the water reduction rate (WRR) was determined. Each of the drying environments was determined by the combination of three different dry bulb temperatures (Tdb) (35, 40 and 45 °C) and three different dew point temperatures (Tdp) (2.6, 10.8 and 16.2 °C). Coffee (Coffea arabica L.) berries of the Topázio Amarelo variety were collected manually and selectively with initial water content of 2.106 ± 0.05 kg.kg-1 (dry basis, db); they were processed by the dry-processing method and dried to a final water content of 0.124 ± 0.05 kg.kg-1 (db) in a fixed-bed dryer combined with a laboratory air conditioning system (LACS). Following this process, the samples were separated into two parts, one containing beans with black-green and sour defects and the other containing the remaining beans, and the colour was read for each group. For all drying combinations, the Midilli model best fit the experimental data. The lowest WRR was 0.063 kg.kg-1.h-1 and occurred in the combination with the Tdb of 35 °C and Tdp of 16.2 °C. In the portion of coffee without defects, among the treatments performed at the Tdb of 35 °C, the combination with the Tdp of 2.6 °C had the lowest luminance values. For the “a” coordinate, the lowest values were found in the combination of the Tdb of 35 °C and Tdp of 2.6 °C.

Kajian Proses Pengeringan Pinang Muda (Areca catechu L) Menggunakan Bahan Bakar Biomassa Kayu : Studi Kasus PT. Areca Agro Aceh

Abstrak. Pengeringan pinang muda menggunakan bahan bakar biomassa kayu dapat dilakukan dengan cara pengovenan. Pengeringan dilakukan sebanyak 3 kali pengulangan pada suhu 60oC, perhitungan masa pinang diukur tiap 3 jam untuk 24 jam pertama, tiap 6 jam untuk hari ke-2 sampai sampai massa bahan konstan. Parameter penelitian untuk mengetahui pinang kering berdasarkan perubahan bobot bahan dan kadar air meliputi laju pengeringan, kecepatan aliran udara, kelembaban udara, suhu dan perubahan berat bahan.Hasil penelitian pada PT. Areca Agro Aceh dalam proses pengeringan pinang muda kering dengan menggunakan bahan bakar biomassa kayu menghasilkan rata-rata kelembaban udara sebesar 56% dengan kecepatan aliran udara rata-rata sebesar 2,22 m/s. Untuk mendapatkan berat pinang muda kering yang konstan, pengeringan ulangan 1 dan ulangan 2 membutuhkan waktu sampai 90 jam sedangkan ulangan 3 membutuhkan waktu pengeringan sampai 96 jam dengan ulangan 1 kadar air awal pinang muda adalah 74,4%. Perubahan mulai terjadi pada jam ke 24 sampai jam ke 90 dengan kadar air akhir pinang muda adalah 22,4% sedangkan pada ulangan 2 kadar air awal pinang muda adalah 74,0% selama 90 jam pengeringan menghasilkan kadar akhir sebesar 21,1%. Pengeringan pinang muda pada ulangan 3 kadar air awalnya sebesar 74,2% menghasilkan kadar air akhir sebesar 21,8% selama 96 jam pengeringan. Laju pengeringan rata-rata selama proses pengeringan sebesar 0,04 bk/jam. Peningkatan laju pengeringan terjadi pada jam ke 21. Study of Batel Nut (Areca catechu L) Drying Process Using Wood Biomass Fuel: A Case Study of PT. Areca Agro AcehAbstract. Drying young areca nut using wood biomass fuel can be done by covenant. Drying is done 3 times repetition at a temperature of 60oC, calculation of areca nut mass is measured every 3 hours for the first 24 hours, every 6 hours for the 2nd day until the mass of material is constant. Research parameters to determine the dry areca nut based on changes in material weight and moisture content include drying rate, air flow velocity, air humidity, temperature and material weight change.The results of research at PT. Areca Agro Aceh in the process of drying areca nut dry using wood biomass fuel produces an average air humidity of 56% with an average air flow velocity of 2.22 m / s. To get a constant weight of dry young areca nut, drying repetition 1 and repetition 2 takes up to 90 hours while repetition 3 requires drying time up to 96 hours with repetition 1 The initial water content of young areca nut is 74.4%. Changes began to occur at the 24th hour to the 90th hour with the final water content of young areca nut being 22.4% while in Repeat 2 the initial water content of the areca nut was 74.0% for 90 hours of drying resulting in a final content of 21.1%. Drying young areca nut on replicate 3, the initial water content of 74.2% produced a final water content of 21.8% for 96 hours of drying. The average drying rate during the drying process is 0.04 bk / hour. Increased drying rate occurs at 21 hours.

Kajian Keseragaman Kualitas Pengeringan Cabai Merah dengan Menggunakan Alat Pengering Tipe Hohenheim

Hasil penelitian pengeringan cabai merah menunjukkan bahwa pada perlakuan tanpa blansir terdapat suhu rata-rata dalam ruang alat pengering pada hari pertama yaitu sebesar 54°C dan pada hari kedua yaitu sebesar 46,6°C,sedangkan suhu rata-rata pada perlakuan diblansir yaitu sebesar 58,6°C. Kelembaban relatif rata-rata dala ruang alat pengering pada perlakuan tanpa blansir pada hari pertama yaitu sebesar 40,2% dan kelembaban relatif rata-rata pada hari kedua yaitu sebesar 51%, sedangkan kelembaban relatif rata-rata pada perlakuan di blansir yaitu sebesar 35,7%. Kadar air akhir pada cabai merah kering dengan perlakuan tanpa blansir yaitu =9,84%, =10,50%, =10,06%, =9,84%,=10,28% dan =9,62%. Sedangkan Kadar air akhir pada cabai merah kering dengan perlakuan diblansir yaitu =9,74%, =9,74%, =10,36%, =10,15%,=9,74% dan =9,53%. Kandungan vitamin C didapat pada cabai merah kering dengan perlakuan tanpa blansir yaitu =39,33%, =43%, =45,6%, =44,93%,=41,27% dan =37,73%. Sedangkan kandungan vitamin C akhir pada cabai merah kering dengan perlakuan diblansir yaitu =34,13%, =37,4%,=40,8%, =38,87%,=36,07% dan =33,36%.Uji organoleptik Cabai merah kering menunjukkan bahwa panelis lebih banyak menyukai dengan perlakuan diblansir.Study The Uniformity Of Drying Quality Of Red Peppers Using Hohenheim Type DryersAbstract. From the results of red pepper cultivation research showed that on treatment without blancing there is average temperature in the dryer room on the first day that is equal to 54%°C and on the second day that is equal to 46,6°C, while the average temperature at the blancing treatment that is equal to 58,6°C. The average relative humidity in the drying chamber on the bluffing treatment on the first day is 40,2% and the average relative humidity on the second day is 51%, while the average relative humidity at the blancing treatment is 35,7%. The final water content of dried red pepper with bluff treatment is P1 = 9,84%, P2=10,50%, P3=10,06%, P4=9,84%, P5=10,28% and P6=9,62%. While the final water content of dried red pepper with blancing treatment is P1=9,74%, P2=9,74%, P3=10,36%, P4=10,15%, P5=9,74% and P6=9.53%. The content of vitamin C was found in dry red chilli with the treatment without blancing that is P1=39,33%, P2=43%, P3=45,6%, P4=44,93%, P5=41,27% and P6=37,73%. While the final vitamin C content of dried red pepper with blancing treatment is P1=34,13%, P2=37,4%, P3=40,8%, P4=38,87%, P5=36,07% and P6=33.36%. The red pepper organoleptic test showed that the panelists preferred the treatment in blancing.

Drying kinetics of ‘babassu’ mesocarp

ABSTRACT ‘Babassu’ mesocarp flour has been used by the pharmaceutical, human food and animal feed industries. However, there is lack of standardization in the production, as well as absence of information on the management of the product’s quality. Thus, the objective of this study was to dry the ‘babassu’ mesocarp in forced-air oven and solar dryer, adjust different mathematical models to the experimental data, as well as to quantify the levels of proteins and crude fiber of the produced flour. The criteria for the adjustment were the coefficient of determination, magnitude of the mean relative error, standard deviation of estimate and the residual distribution trend. Drying in the shortest time occurred in oven at 60 °C (370 min), leading to water content of 4.62%, while in the solar dryer the final water content was 8.07% in 6 days. The mathematical model Two Terms showed the best fit to the experimental data for oven drying and the Midilli model showed the best fit in solar dryer. There was an increase in protein content with the drying in solar dryer and oven at 40, 50 and 60 °C (1.36, 1.33, 1.15 and 1.37%, respectively) in relation to fresh mesocarp (0.88%). Drying in both oven and solar dryer promoted increase of protein in the flour.

Study on the Sludge Dewatering Based on the Filtration Characteristic of Geotextiles

The dehydration and minimization of sludge depended on filtering technology of geotextile is a hot issue in environmental project. By studying related process, the types, weaving forms, weaving structures and pore sizes of geotextile were tested. CPAM was the optimal flocculant with the dose of 90-110 mg/L and twill weaving geotextile with pore size of 0.5 mm was best. The final water content of sludge could drop to 40 %.