Environmental Engineering

At 1-1, for \mathrm{R}_{3}
\begin{aligned} \mathrm{Q}_{3} & =\mathrm{Q}_{1}+\mathrm{Q}_{2} \\ & =5+15=20 \mathrm{~m}^{2} / \mathrm{sec} \\ \mathrm{C}_{3} & =\frac{\mathrm{Q}_{1} \mathrm{C}_{1}+\mathrm{Q}_{2} \mathrm{C}_{2}}{\mathrm{Q}_{1}+\mathrm{Q}_{2}} \\ &=\frac{5 \times 8+15 \times 12}{5+15} \\ & =11 \mathrm{Kg} / \mathrm{m}^{3} \end{aligned}

At 2-2, For \mathrm{R}_{5}
\mathrm{Q}_{5}=\mathrm{Q}_{3} \mathrm{Q}_{4}=10-3=17 \mathrm{~m}^{3} / \mathrm{sec}
\mathrm{C}_{5}=\mathrm{C}_{3}=11 \mathrm{Kg} / \mathrm{m}^{3}

At 3-3 for \mathrm{R}_{7}
\begin{aligned} \mathrm{Q}_{7} & =\mathrm{Q}_{6}+\mathrm{Q}_{5}=17+8=25 \mathrm{~m}^{3} / \mathrm{sec} \\ \mathrm{C}_{7} & =\frac{\mathrm{Q}_{6} \mathrm{C}_{6}+\mathrm{Q}_{6} \mathrm{C}_{5}}{\mathrm{Q}_{6}+\mathrm{Q}_{5}} \\ & =\frac{8 \times 10+17 \times 11}{8+17}=10.68 \mathrm{Kg} / \mathrm{m}^{3} \end{aligned}
Answer : 10.6 \mathrm{~kg} / \mathrm{m}^{3}.

Calculation of B O D_{s} :
\mathrm{C}_{5} \mathrm{H}_{7} \mathrm{O}_{2} \mathrm{~N}+5 \mathrm{O}_{2} \rightarrow 5 \mathrm{CO}_{2}+\mathrm{NH}_{3}+2 \mathrm{H}_{2} \mathrm{O}
Considering 1 mole of biomass
\mathrm{BOD}_{4}=160 \mathrm{gm} / \mathrm{mol}
\therefore \quad \mathrm{BOD}_{5}=\mathrm{BOD}_{4}\left(1-\mathrm{e}^{-\mathrm{k}_{0} \mathrm{t}}\right)
=160\left(1-e^{-0.23 \times 5}\right)
=160 \times 0.6833
=109.34 \mathrm{gm} / \mathrm{mol}

Calculation of TOC:
\mathrm{TOC}=\frac{12 \times 5}{113} \times 113=60 \mathrm{gm} / \mathrm{mol}
( \because 1 mole biomass is considered)
\therefore Required Ratio =\frac{109.34}{60}=1.82

A bulking agent (wood ships shredded leaves or types) is intended to support the structure of sludge by increasing its porosity to encourage effective aeration.

In-vessel composting systems can be divided into plug flow and agitated bed modes. In plug flow mode, the relationship between particles in the composting mass stays the same through the process and the system operates on first-in, first-out principle. In an agitated bed system, composting material is mixed mechanically during the processing.

The heat produced in aquatic composting cause any surplus moisture to be extracted as water vapour and hence no leachate is produced.

Actinomycetes are aerobic, spore forming positive bacteria. These are thermophilic species and their development depends on aerobic conditions, temperature and water content. The heat produced in aerobic composting helps support the growth of these species.

Leachate can generated from vegetable wastes.

Total dissolved solids comprise of inorganic salts, principally calcium, magnesium, potassium, sodium bicarbonates, chlorides, sulfates and some small amount of organic matter that are dissolved in water.
Hardness is due to presence of multivalent cations. In most cases, it is due to the presence of soluble bicarbonates, chlorides and sulfates of calcium and magnesium.
Too much phosphorous can cause increased growth of algae and large aquatic plants. It can result in decreased levels of dissolved oxygen and the process is called 'Eutrophication'.
Ammonia creates a large chlorine demand, as the ammonia is converted to nitrogen gas and the chlorine becomes chloride during disinfection of water by chlorination.
Presence of particulate matter decreases the effectiveness of UV disinfection or chlorine disinfection by shielding the targeted microorganisms.

Aromatic hydrocarbons such as 3, 4benzpyrene, other polycyclic organic compounds which are originated due to incomplete combustion of hydrocarbons are considered to be carcinogenic agents. These are responsible for cancer.
Sulphur dioxide \left(\mathrm{SO}_{2}\right) : It is an irritant gas which effects mucous membrane when inhaled. It leads to bronchial spasms. Asthma patients are badly affected.
Carbon Monoxide (CO) : Carbon monoxide has a strong affinity for combining with the haemoglobin of the blood to form carboxyhemoglobin, \mathrm{COHb}. This reduces the ability of the haemoglobin to carry oxygen to the body tissues. CO has about two hundred time the affinity of oxygen for attaching itself to the haemoglobin, so that low levels of CO can still result in high levels of \mathrm{COHb}. Carbon monoxide also affects the central nervous system.
Ozone \left(\mathrm{O}_{3}\right) can damage the tissue of the respiratory tract, causing inflammation and irritation, and result in symptoms such as coughing, chest tightness and worsening of asthma symptoms. In addition, ozone causes substantial damage to crops, forests and native plants.