Performance of Oyster Shell Powder Size on Methane Gas Generation in Two-Stage Anaerobic Digestion System

An anaerobic digester system is a sequence of process to digest biodegradable waste into biogas in the absence of oxygen. In two-stage anaerobic digestion system acid-forming steps or hydrolysis stage are separated from the methane forming steps. Although hydrolysis stage tends to get too acidic, addition of alkali substance can prevent pH from dropping too low so as to maintain good decomposition condition for microorganism. Oyster shell powder is a useful pH control additive containing CaCO3 at high percentage that can neutralize acid. In this study, the performances between industry-made fine oyster shell (IOS) powder (size 10.5 μm) and manually ground oyster shell (OS) powder (size < 1 mm) in methane generation yield were compared. NaOH, which is an alkali reagent for controlling pH, also used in comparison. The result showed that at the end of the hydrolysis stage, IOS powder increased pH up to 6.63, NaOH did almost the same (6.72), and OS powder was the lowest (6.1). In liquid residue, ratio of inorganic ash content with IOS treatment was the highest (2.1 %), but OS was the lowest (1.4 %). In the methanogenesis stage, CH4 concentration with NaOH treatment was the highest (80 %) compared to oyster shell powders: 74.33 % in IOS and 74.24 % in OS. Average methane yield over observation period of IOS treatment was the highest (533.9 mL/gVS), followed by alkali (487.3 mL/gVS) and OS (413.7 mL/gVS). Total CH4 from IOS treatment was 37 % and 8 % higher than OS and alkali treatment. Powder size of oyster shell greatly affected pH control, methane yield, and solid-liquid separation, but not methane concentration. Using IOS powder as pH control in hydrolysis of two-stage anaerobic system resulted in 78 % less cost than using NaOH

Helminth Eggs Parameter of Water Spinach Agriculture Field in Bandung

The high prevalence of helminth infection in Indonesia had encouraged the government to issue the Regulation of the Minister of Health concerning the Prevention of Soil-transmitted Helminths in 2017. Researches on the presence of helminth eggs in the environment, in soil and water as a media for transmitting the disease, are very few. Aim: The aim was conducted to investigate the potential presence of helminth eggs causing STH infections in two urban agricultural areas in northern and southern part of Bandung City. Methodology and results: Samples of water from the inlet and plantation area, as well as soil and water spinach produced by both regions, were collected and analyzed for the presence of helminth eggs using modified Bailinger methods. The number of helminth eggs of 1–119 eggs/L in water, soil, and vegetable samples. Conclusion, significance, and impact study: The results confirmed that the irrigation water used in both areas has been contaminated by feces. The average number of fecal coli exceeds the allowable value for the irrigation water source based on the Grade 4 of water quality criteria in Indonesia. Variations in the number of helminth eggs found in the samples can be caused by environmental conditions such as temperature, humidity, and soil types. The presence of helminth eggs in irrigation water and land samples exceeds the value recommended by WHO (2006) in the guidelines for the safe use of wastewater for agriculture. It can lead to an increased risk of helminth infection to consumers, agricultural workers, as well as residents around the farmland

Helminth eggs assessment of fecal sludge in urban area of Bandung, Indonesia

Soil-transmitted helminth eggs present to be non-excludable parameter for water quality and sanitation since they are linked to public health concern. Unfortunately, investigation of helminth eggs presence in wastewater is very limited in Indonesia. The result of previous study confirmed helminth eggs presence in irrigation water and land samples in agriculture field in urban area of Bandung. Inappropriate of wastewater treatment system and reuse of unsafe wastewater are the reason why helminth egg were found in agriculture area. Therefore, this study was conducted to get better understanding of helminth eggs presence in wastewater especially in fecal sludge of the city. Samples were collected from desludging trucks servicing residential and non-residential septic tanks from total 17 areas. Modification of US EPA method is used to analyse and enumerate the viable helminth eggs. There are big variations amount of helminth egg in samples from different area, from 4 eggs/L to 617 eggs/L. We found more than 10 species of helminth eggs. Hookworm egg counts were higher than those of Fasciola hepatica and Ascaris lumbricoides. This study also showed that septic tank inefficient for reducing helminth eggs presence in fecal sludge and for fulfilled recommendation of WHO for safe water reuse