You need to design a treatment plant for flowback water from Marcellus Shale dri

Question

You need to design a treatment plant for flowback water from Marcellus Shale drilling. The well produces 1 MGD The water coming out of the plant contains 200 ppm ultimate BOD with a pH 6. The first step is to raise the pH of the water to precipitate some of the salts. You are going to mix the flowback water with another stream containing water at a pH of 12 in a CSTR. If you want the combined stream to have a pH of 9.5, calculate the flowrate of the incoming stream. Assume no reaction. (Hint: Do a material balance on OH (10 pts) 7. GPD 8. After treating the water you need to decrease the pH to 6. The water is held in a 100,000 gallon "pond" You have a 0.5 M acid solution with a pKa 8. How many mls of this solution are required to change the pH from 9.5 to 6? (10 pts)

Explanation / Answer

ss can be subdivided into the following four phases, each requiring its own characteristic group of micro-organisms: • Hydrolysis: conversion of non-soluble biopolymers to soluble organic compounds • Acidogenesis: conversion of soluble organic compounds to volatile fatty acids (VFA) and CO2 • Acetogenesis: conversion of volatile fatty acids to acetate and H2 • Methanogenesis: conversion of acetate and CO2 plus H2 to methane gas A simplified schematic representation of anaerobic degradation of organic matter is given as Figure 1. The acidogenic bacteria excrete enzymes for hydrolysis and convert soluble organics to volatile fatty acids and alcohols. Volatile fatty acids and alcohols are then converted by acetogenic bacteria into acetic acid or hydrogen and carbon dioxide. Methanogenic bacteria then use acetic acid or hydrogen and carbon dioxide to produce methane. For stable digestion to proceed it is vital that various biological conversions remain sufficiently coupled during the process, to prevent the accumulation of intermediate compounds. For example, an accumulation of volatile fatty acids will result in a decrease of pH under which conditions methanogenesis cannot occur anymore, which - 59 - Amino acids sugars Free long chain fatty acids + glycerol Volatile fatty acids, alcohol Methane carbon dioxide ammonia Hydrolysis Acidogenesis Acetogenesis Methanogenesis Acetic acid Suspended, colloidal organic matter protein carbohydrate lipid Hydrogen carbon dioxide

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.