Ключевые слова: above, aerial, biology, biomass, circle, city, clean, cleaning, construction, dirty, down, ecology, environment, environmental, facility, factory, farm, flow, green, health, hong, industrial, industry, kong, outdoors, over, plant, pollution, processing, purification, purified, purity, recycle, recycled, recycling, sewage, sha tin, smell, storage, tank, top, top down, treatment, view, waste, wastewater, water,